Introduction to the Lumbar Fusion GuidelinesAs scientific understanding of the pathophysiology ofdegenerative disease of t...
computerized literature searches), evaluation and classifi-cation of the quality of evidence provided by the literature,in...
RecommendationsStandards. It is recommended that functional outcomebe measured in patients treated for low-back pain due t...
and 2003 was performed. A search using the subject head-ing “lumbar fusion” yielded 3708 citations. The followingsubject h...
J. Neurosurg: Spine / Volume 2 / June, 2005Functional Outcome641TABLE1Evidentiarytablesummarizingpublishedstudiesinvolving...
D. K. Resnick, et al.642 J. Neurosurg: Spine / Volume 2 / June, 2005TABLE1ContinuedAuthors&YearClassDescriptionResultsConc...
J. Neurosurg: Spine / Volume 2 / June, 2005Functional Outcome643internal consistency was greater than 0.90. Self-assess-me...
and Waddell–Main scales. Despite a statement that exter-nal reliability was studied, no mention was made of thestatistical...
responsiveness. The validity of satisfaction measures hasbeen examined but their external reliability has not.Slosar and c...
ability Index, Roland-Morris Disability Questionnaire, andShort-Form 36. Spine 28:1601–1607, 200316. Greenough CG, Fraser ...
RecommendationsStandards. There is insufficient evidence to recommenda standard for assessment of economic outcome followi...
parison,” or “cost effectiveness” resulted in 58 matches.Titles and abstracts of the articles were reviewed. Clinicalserie...
J. Neurosurg: Spine / Volume 2 / June, 2005Economic Outcome649TABLE1Summaryofstudiesinvolvingassessmentofeconomicoutcomeaf...
associated with higher risk for complications than lumbarsurgery without fusion.Katz and colleagues10completed a prospecti...
come questionnaires and return-to-work status. In an over-all assessment, 63% in the surgical group indicated theywere bet...
for posterolateral spinal fusion: randomized clinical study witha 5-year follow-up. Spine 27:1269–1277, 20023. Davis H: In...
RecommendationsStandards. Static lumbar radiographs are not recom-mended as a stand-alone means to assess fusion status fo...
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine
Upcoming SlideShare
Loading in …5
×

Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine

1,245 views

Published on

Published in: Health & Medicine
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
1,245
On SlideShare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
24
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Guidelines for the preformance of fusion procedures for degenerative disease of the lumbar spine

  1. 1. Introduction to the Lumbar Fusion GuidelinesAs scientific understanding of the pathophysiology ofdegenerative disease of the lumbar spine has increased, thepossibilities for correcting the underlying problem and theresulting improvement in clinical function have expandedexponentially. Fueled by advances in material technologyand surgical technique, treatment of greater numbers ofindividuals suffering from lumbar spinal disease has prolif-erated. Using data from the National Hospital DischargeSurvey, Deyo and colleagues4described a 200% increase inthe frequency of lumbar fusion procedures in the 1980s.Davis3observed that the age-adjusted rate of hospitaliza-tion for lumbar surgery and lumbar fusion increased greaterthan 33% and greater than 60%, respectively, from 1979to 1990. Lumbar fusion has been described as a treatmentof symptomatic degenerative disc disease, spinal stenosis,spondylolisthesis, and degenerative scoliosis. Lumbar fu-sion has been performed to treat acute and chronic low-back pain, radiculopathy, and spinal instability.As practitioners have become caught up in the excite-ment of what can be accomplished, there are increasingquestions regarding what should be done and how. Thesequestions are being addressed in this current document,Guidelines for the Performance of Fusion Procedures forDegenerative Disease of the Lumbar Spine.In January 2003, a group was formed at the request ofthe leadership of the CNS by the executive committee ofthe American Association of Neurological Surgeons/CNSJoint Section on Disorders of the Spine and PeripheralNerves to perform an evidence-based review of the litera-ture on lumbar fusion procedures for degenerative diseaseof the lumbar spine and to formulate treatment recom-mendations based on this review. In March 2003, thisgroup was convened. Invitations were extended to approx-imately 12 orthopedic and neurosurgical spine surgeonsactive in the Joint Section or in the North American SpineSociety to ensure participation of nonneurosurgical spinesurgeons. The 50 recommendations that follow this intro-duction represent the product of the work of the group,with input from the Guidelines Committee of the Ameri-can Association of Neurological Surgeons/CNS and theClinical Guidelines Committee of North American SpineSociety.The first few papers in this series deal with the meth-odology of guideline formation and the assessment ofoutcomes following lumbar fusion. The next series of rec-ommendations involve the diagnostic modalities helpfulfor the pre- and postoperative evaluation of patients con-sidered candidates for or treated with lumbar fusion, fol-lowed by recommendations dealing with specific patientpopulations. Finally, several surgical adjuncts, includingpedicle screws, intraoperative monitoring, and bone graftsubstitutes are discussed, and recommendations are madefor their use.MethodologyThe development of practice parameters, guidelines, orrecommendations is an onerous and time-consuming pro-cess. It consists of literature gathering (primarily throughJ. Neurosurg: Spine / Volume 2 / June, 2005J Neurosurg: Spine 2:637–638, 2005Guidelines for the performance of fusion proceduresfor degenerative disease of the lumbar spine.Part 1: introduction and methodologyDANIEL K. RESNICK, M.D., TANVIR F. CHOUDHRI, M.D., ANDREW T. DAILEY, M.D.,MICHAEL W. GROFF, M.D., LARRY KHOO, M.D., PAUL G. MATZ, M.D.,PRAVEEN MUMMANENI, M.D., WILLIAM C. WATTERS III, M.D., JEFFREY WANG, M.D.,BEVERLY C. WALTERS, M.D., M.P.H., AND MARK N. HADLEY, M.D.Department of Neurosurgery, University of Wisconsin, Madison, Wisconsin; Department ofNeurosurgery, Mount Sinai Medical School, New York, New York; Department of Neurosurgery,University of Washington, Seattle, Washington; Department of Neurosurgery, Indiana University,Indianapolis, Indiana; Departments of Orthopedic Surgery and Neurosurgery, University ofCalifornia at Los Angeles, California; Department of Neurosurgery, University of Alabama atBirmingham, Alabama; Department of Neurosurgery, Emory University, Atlanta, Georgia;Bone and Joint Clinic of Houston, Texas; and Department of Neurosurgery, Brown University,Providence, Rhode IslandKEY WORDS • fusion • lumbar spine • practice guidelines • treatment outcome637Abbreviation used in this paper: CNS = Congress of Neurologi-cal Surgeons.SpineJune2005 5/24/05 10:42 AM Page 637
  2. 2. computerized literature searches), evaluation and classifi-cation of the quality of evidence provided by the literature,interpretation of this evidence to draw meaningful conclu-sions, and formulation of recommendations based on thisprocess. The process is meant to be clear, and the reader isencouraged to read the entire document as opposed to therecommendations alone.Guideline development within the specialty of neuro-surgery has followed a rigorous process delineated early onin the advent of specialty-specific guidelines.5Followingrecommendations proposed by other specialty societies,the process used in neurosurgical guideline developmentdivides the types of literature into classes depending on thescientific strength of the study design.6Because the publi-cation of the ground-breaking and exemplary Guidelinesfor the Management of Severe Head Injury,1,2an effort hasbeen made to adhere to these strict criteria for practice rec-ommendations. The definitions of classes of evidence fortherapeutic effectiveness are as follows: Class I, evidencefrom one or more well-designed, randomized controlledclinical trials, including overviews of such trials; Class II,evidence from one or more well-designed comparative cli-nical studies, such as nonrandomized cohort studies, case-control studies, and other comparable studies, includingless well-designed randomized controlled trials; and ClassIII, evidence from case series, comparative studies withhistorical controls, case reports, and expert opinion as wellas significantly flawed randomized controlled trials. Fordiagnostic tests, and clinical assessment, other study de-signs are used, and therefore the classification systems areslightly different, but still result in Classes I, II, and III evi-dence. This is reviewed in detail elsewhere.6Class I evidence is used to support treatment recom-mendations of the strongest type, called practice standards,reflecting a high degree of clinical certainty. Class II evi-dence is used to support recommendations called guidelines,reflecting a moderate degree of clinical certainty. Othersources of information, including observational studies suchas case series and expert opinion, as well as fatally flawedrandomized controlled trials (Class III evidence), supportpractice options reflecting unclear clinical certainty.On the surface, this appears to be a fairly straightfor-ward task, but within the process the most difficult aspectis evaluating the quality of the evidence in each type.Disappointingly, studies in which evidence should be con-sidered Class I or II because of study type have to bedowngraded to a lower class of evidence due to method-ological flaws that could cause false conclusions to bedrawn from the evidence. This is discussed extensivelywithin each topic, and all cited evidence is listed in outlineform in the evidentiary tables, so as to ensure transparen-cy of the development process.The group culled through literally thousands of refer-ences to identify the most scientifically robust citationsavailable concerning each individual topic. Not every ref-erence identified is cited. In general, if high-quality (ClassI or II) medical evidence was available on a particulartopic, poorer-quality evidence was only briefly summa-rized and rarely included in the evidentiary tables. If nohigh-quality evidence existed, or if there was significantdisagreement between similarly classified evidence sourc-es, then the Class III and supporting medical evidencewere discussed in greater detail. If multiple reports wereavailable that provided similar information, a few werechosen as illustrative examples.A consistent finding during the exploration of many ofthese topics was that many investigators reported studies inwhich the designs were unsophisticated. The use of invalidoutcome measures, the lack of an appropriate power analy-sis, and the failure to identify distinct patient populations forstudy inhibited our ability to draw meaningful conclusionsfrom many reports. Specific examples are provided in thetext of each topic. Suggestions for future research are madeat the conclusion of each paper. We, as spine surgeons, mustimprove the quality of our research practices to provide con-vincing evidence that the therapies we strongly believe inare safe, effective, and make economic sense.During the development of these guidelines, the authorsoften found that their preconceived ideas regarding theproper treatment of patients with chronic low-back painwere founded on poor-quality or controversial medical evi-dence. Some recommendations have resulted in changes inthe authors’ practice patterns after every effort was made toclassify the evidence and to interpret the results of the vari-ous studies in a scientifically rigorous fashion. Many rec-ommendations are made at the lowest level, meaning thatdefinitive evidence is lacking to support the recommenda-tion but that evidence exists at some level. Some readerswill undoubtedly disagree with one or more of our recom-mendations or with the level of a given recommendation.The justification for all of the recommendations is includedin the scientific foundation portion and the summary sectionof each guideline. If the job has been done correctly, the rea-soning behind the recommendation should be clear.It is our hope, as well as that of the participating orga-nizations, that these guidelines will help to elucidate thecurrent knowledge on the topic of lumbar fusion and willstimulate the development of more rigorous scientific evi-dence justifying or refining—or, if appropriate, eliminat-ing—aspects of this form of treatment.References1. Bullock R, Chesnut RM, Clifton G, et al: Guidelines for themanagement of severe head injury. Brain Trauma Foundation.J Neurotrauma 13:639–734, 19962. Bullock R, Chesnut, RM, Clifton G, et al: Guidelines for themanagement of severe traumatic brain injury. J Neurotrauma17:451–627, 20003. Davis H: Increasing rates of cervical and lumbar spine surgeryin the United States, 1979–1990. Spine 19:1117–1124, 19944. Deyo RA, Cherkin D, Conrad D, et al: Cost, controversy, crisis:low back pain and the health of the public. Annu Rev PublicHealth 12:141–156, 19915. Rosenberg J, Greenberg MK: Practice parameters: strategies forsurvival into the nineties. Neurology 42:1110–1115, 19926. Walters BC: Clinical practice parameter development, in BeanJR (ed): Neurosurgery in Transition. Baltimore: Williams &Wilkins, 1998, pp 99–111Manuscript received December 7, 2004.Accepted in final form February 18, 2005.Address reprint requests to: Daniel K. Resnick, M.D., Depart-ment of Neurological Surgery, University of Wisconsin MedicalSchool, K4/834 Clinical Science Center, 600 Highland Avenue,Madison, Wisconsin 53792. email: Resnick@neurosurg.wisc.edu.D. K. Resnick, et al.638 J. Neurosurg: Spine / Volume 2 / June, 2005SpineJune2005 5/24/05 10:42 AM Page 638
  3. 3. RecommendationsStandards. It is recommended that functional outcomebe measured in patients treated for low-back pain due todegenerative disease of the lumbar spine by using reliable,valid, and responsive scales. Examples of these scales inthe low-back pain population include the following: TheSpinal Stenosis Survey of Stucki, Waddell–Main Ques-tionnaire, RMDQ, DPQ, QPDS, SIP, Million Scale, LBPRScale, ODI, the Short Form–12, the JOA system, theCBSQ, and the North American Spine Society LumbarSpine Outcome Assessment Instrument.Guidelines. There is insufficient evidence to recom-mend a guideline for assessment of functional outcomefollowing fusion for lumbar degenerative disease.Options. Patient satisfaction scales are recommendedfor use as outcome measures in retrospective case series,where better alternatives are not available. Patient satis-faction scales are not reliable for the assessment of out-come following intervention for low-back pain.RationaleLumbar spinal fusion is an increasingly common pro-cedure performed as an adjunct in the surgical manage-ment of patients with degenerative lumbar disease andinstability. As the frequency and complexity of lumbarfusion surgery increases, there is a tendency for costs andcomplication rates to increase as well.20With fewer hospi-tal resources available, the ability to assess objectively thefunctional outcome following lumbar fusion and to corre-late patient outcome with the economic consequences oftreatment is important.Various assessment tools are available for measuringfunctional outcomes in patients who have undergone lum-bar fusion. These outcomes may vary widely in the samepopulation depending on whether subjective or objectivemeasures have been used.17Examples of objective outcomemeasures include physiological, anatomical, economic,health-related QOL, and mortality measurements.10Objec-tive outcome measures may be classified into functionalquestionnaires, global ratings (satisfaction), economic fac-tors (employment, disability, and cost), and physical factors(activities).21The purpose of this review was to identifyvalid, reliable, and responsive measures of functional out-comes after lumbar fusion for degenerative disease.Search CriteriaA computerized search of the National Library of Me-dicine database of the literature published between 1966J. Neurosurg: Spine / Volume 2 / June, 2005J Neurosurg: Spine 2:639–646, 2005Guidelines for the performance of fusion proceduresfor degenerative disease of the lumbar spine.Part 2: assessment of functional outcomeDANIEL K. RESNICK, M.D., TANVIR F. CHOUDHRI, M.D., ANDREW T. DAILEY, M.D.,MICHAEL W. GROFF, M.D., LARRY KHOO, M.D., PAUL G. MATZ, M.D.,PRAVEEN MUMMANENI, M.D., WILLIAM C. WATTERS III, M.D., JEFFREY WANG, M.D.,BEVERLY C. WALTERS, M.D., M.P.H., AND MARK N. HADLEY, M.D.Department of Neurosurgery, University of Wisconsin, Madison, Wisconsin; Department ofNeurosurgery, Mount Sinai Medical School, New York, New York; Department of Neurosurgery,University of Washington, Seattle, Washington; Department of Neurosurgery, Indiana University,Indianapolis, Indiana; Departments of Orthopedic Surgery and Neurosurgery, University ofCalifornia at Los Angeles, California; Department of Neurosurgery, University of Alabama atBirmingham, Alabama; Department of Neurosurgery, Emory University, Atlanta, Georgia;Bone and Joint Clinic of Houston, Texas; and Department of Neurosurgery, Brown University,Providence, Rhode IslandKEY WORDS • fusion • lumbar spine • practice guidelines • treatment outcome639Abbreviations used in this paper: CBSQ = Curtain BackScreening Questionnaire; DPQ = Dallas Pain Questionnaire; DRI =Disability Rating Index; FSQ = Functional Status Questionnaire;JOA = Japanese Orthopaedic Association; LBPR = Low Back PainRating; ODI = Oswestry Disability Index; QOL = quality of life;QPDS = Quebec Pain Disability Scale; RMDQ = Roland–MorrisDisability Questionnaire; SF-36 = Short-Form–36; SIP = SicknessImpact Profile; VAS = visual analog scale.SpineJune2005 5/24/05 10:42 AM Page 639
  4. 4. and 2003 was performed. A search using the subject head-ing “lumbar fusion” yielded 3708 citations. The followingsubject headings were combined: “lumbar fusion and out-comes.” Approximately 204 citations were acquired. Onlycitations in English were selected. A search of this set ofpublications with the key words “functional outcome” and“satisfaction” resulted in 107 matches. Alternative search-es included each disability index by name. Titles and ab-stracts of the articles were reviewed and clinical seriesdealing with adult patients treated with lumbar fusion fordegenerative lumbar disease were selected for detailed an-alysis. Additional references were culled from the ref-erence lists of remaining articles. Among the articlesreviewed, 30 studies were included that dealt with lum-bar fusion, functional outcomes, and satisfaction surveys.Nineteen of these articles were studies in which the au-thors examined the reliability of functional outcome mea-sures. In another seven articles investigators examined theutility of these functional outcome measures in the settingof lumbar fusion. Two articles were overviews on func-tional outcome and lumbar degenerative disease. All pa-pers providing Class I medical evidence are summarizedin the evidentiary table (Table 1).Scientific FoundationAssessment of Functional OutcomeTo assess outcome following treatment properly, afunctional instrument must fulfill three criteria.11,21First, itmust be reliable.10,11Repetition of the functional assess-ment should be consistent within (internal reliability) andbetween (external reliability) observers. If a functional in-strument contains multiple domains, each should correlatewith the final outcome (internal consistency). Second, afunctional instrument must be valid.21It should measure theproperty intended. For example, an instrument assessingdysfunction due to leg pain would be expected to correlatewith a reduction in the ability to walk a given distance.Finally, the instrument should be responsive.21The instru-ment should be able to detect differences in severity amongpopulations. If an instrument measures low-back pain andthis pain improves with physical therapy, the instrumentshould reflect that improvement quantitatively. When eval-uating the utility of a functional tool, the initial assessmentshould emphasize reliability. If a functional instrumentdoes not produce reliable results, its validity and respon-siveness are irrelevant.In terms of grading the quality of outcomes instruments,␬ and ␣ values are used. The ␬ value refers to the degreeof correlation of interrater observations (reliability). Inpatient-based assessments, it indicates consistency in res-ponse at a given time point. The ␣ value, often calculatedusing the Cronbach ␣ test, reflects the degree to whicheach domain of a multidomain outcome measure corre-lates with the final result.7For example, an assessmenttool for pain may contain physical, psychological, and so-cial domains. Each domain score should correlate with thefinal score. For a study to provide Class I medical evi-dence regarding functional outcomes, the outcomes toolused must have a ␬ value greater than 0.8. Class II med-ical evidence requires an outcomes tool to have a ␬ greaterthan 0.6. Any outcome scale with a ␬ value less than 0.6is considered to provide Class III medical evidence for theassessment of outcomes following an intervention.18Roland and Morris30,31followed 230 patients of whom193 were studied up to 4 weeks after their initial presenta-tion. Functional disability was assessed using a 24-itemdisability questionnaire (the RMDQ) with statements de-rived from the SIP and relating to the lower back. Re-liability was ascertained in 20 patients with an externalreliability greater than 0.91. Internal consistency appearedto be greater than 0.8. Validity was confirmed after com-parisons to a six-point pain rating scale and physical signsascertained by an examining physician.31In this group,60% of patients appeared to improve over the 4-weekperiod, whereas 20% worsened. Absence from work ap-peared to correlate less well with disability, as only 8%of the employed were unable to work.30Using the ODI,Fairbank and colleagues12followed 25 patients with acutelow-back pain in whom a reasonable prognosis was ex-pected. The questionnaire has 10 categories with six gra-dations each, for a total score of 50. It was completed atweekly intervals over a period of 3 weeks. Reliability(␬ Ͼ 0.95) was confirmed in 22 patients who repeated thequestionnaire over 2 days. Validity was demonstrated aspatients improved over 3 weeks. Paired t-tests revealed asignificant improvement in ODI scores during this timeperiod (p Ͻ 0.005).Leclaire and colleagues24observed patients who pre-sented with acute low-back pain alone (100 cases) or ac-companied by radiculopathy (100 cases). The cohort wasfollowed using the RMDQ and ODI questionnaires. In theradiculopathy group, ODI and RMDQ scores were signif-icantly more severe (higher) than in the low-back pain–alone group (p Ͻ 0.0001). The two scales had a moderatecorrelation to each other in each subgroup (r = 0.72 [ra-diculopathy]; r = 0.66 [lumbago]; p Ͻ 0.0001). In a cohortof patients with low-back pain, the JOA score was used asa psychometric measure. External reliability was strong(␬ Ͼ 0.90) when 15 patients reassessed their status withno change in their symptomatology. Interobserver externalreliability among physicians was also sound (␬ Ͼ 0.90) in30 patients reassessed using the JOA. Validity was estab-lished by a strong correlation to the RMDQ, ODI, and theSF-36.15In several different groups with lumbar degener-ative disease, the North American Spine Society LumbarSpine Outcome Assessment tool was used to assesspatients who had undergone conservative or decompres-sive therapy.8In this study, 136 of 206 questionnaires weresuccessfully completed. External reliability was assessedin 64 patients. Both internal and external reliability wasstrong (␬ Ͼ 0.90). The test was determined to be a validmeasure compared with existing instruments.The SIP is a traditional general functional outcomemeasure, with 136 items in 12 categories, that has beenevaluated in the general populace for a variety of condi-tions. It has been applied to patients with low-back painand degenerative lumbar disease. Bergner, et al.,1exam-ined the use of this general health instrument in 1108 pa-tients with multiple medical problems including rheuma-toid arthritis and hip osteoarthritis.1Simultaneous withthis questionnaire were a clinician’s assessment of physi-cal function and patients’ self-assessment of the severityof sickness and dysfunction. In this setting, the test–retest(external) reliability of SIP was greater than 0.90, and itsD. K. Resnick, et al.640 J. Neurosurg: Spine / Volume 2 / June, 2005SpineJune2005 5/24/05 10:42 AM Page 640
  5. 5. J. Neurosurg: Spine / Volume 2 / June, 2005Functional Outcome641TABLE1EvidentiarytablesummarizingpublishedstudiesinvolvingClassImedicaldata*Authors&YearClassDescriptionResultsConclusionsFairbank,etal.,1980I25patientsw/acuteLBP&reasonableprognosiswereTest–retestreliabilitywas␬Ͼ0.95(pϽ0.001)inTheODIisareliable&validmeasureindetectingstudiedatwklyintervalsfor3wksw/afunctional22patients.Overthe3-wkinterval,significantim-changesintheLBP&itsfunctionalseverity.disabilitysurvey.TheODIhas10categorieseachprovementwasnotedclinically&wasdetectedw/6responsesgraded0–5.Atotalof50pointsareusingtheODI.Apairedt-testrevealedasignificantpossible.improvementontheODIover3wks(pϽ0.05).Bergner,etal.,1981I1108patientsinageneralpopulacew/multipleprob-Externalreliabilityw/in&btwnobserverswasSIPmeasuresindependentfunction,physicalwellness,lemsincludingRA&hiposteoarthritis.Patients␬Ͼ0.90.Internalconsistencywas␣Ͼ0.90.&psychosocialwellness.Itisreliable&valid.Rea-wereevaluatedusingtheSIP.AssessmentwasdoneSelf-assessmentofsickness&dysfunctionhadsonablemeasurestouseforoutcomeareSIP&self-byaclinicianforphysicalmeasures.Self-assess-areliabilityof␬Ͼ0.60.TheSIPappearedtocor-assessmentofsickness&dysfunction.mentwascompletedforseverityofsickness&relatew/theself-assessmentofsickness&dys-dysfunction.function(correlationϾ0.50).Million,etal.,1982I19patientsw/chronicLBP.TheirfunctionaldisabilityExternalreliabilitywasstrongbtwn&w/inobserversTheMillionScaleisareliableindicatoroftheseveritywasstudiedusingtheMillionScalewhichwasa␬Ͼ0.90.Asavaliditymeasure,theMillionoflumbago&isresponsiveintheearlyphaseofVASexamining15subjectivevariablesreflectingScaleappearedtoreflectchangesinphysicalmea-treatment.Itsresponsivenessappearsbetterthanthattheseverityoflumbago.Asoftcorsetw/&w/osurements.At4&8wksafterrigidbracing,pa-ofobjectivemeasurementsincludinglumbarmotionsupportwasusedtotesttheresponsivenessofthetientsimprovedclinically,&thisresponsiveness&straightlegraising.MillionScale.wasdetectedbytheMillionScale(pϽ0.05at4wks&pϽ0.01at8wks).Roland&Morris,1983I230patientsw/acutelumbago;193werestudiedat0,Externalreliabilitywas␬Ͼ0.90&internalconsist-TheRMDQisreliableforassessmentofacuteLBP.1,&4wksaftertheepisode.Test–testreliabilityency␣Ͼ0.80.Constructvaliditydemonstratedwasdoneon20/230patients.TheconstructvaliditythattheRoland–Morrisquestionnairewasabletowasqualitativelyassessedbycomparingthisfunc-detectqualitativelypatientsw/pooreroutcomestionalquestionnairetothepainratingscale.fromacutelumbago;however,nospecificanaly-siswasdone.Roland&Morris,1983I230patientsw/acutelumbagowhowerestudiedat0,Ͼ60%ofpatientshadimprovementoverthe4-wkNospecificstatisticstestedthecorrelationinthisstudy.1,&4wks.Thedisabilityquestionnairewasad-period,whereas20%hadanincreaseindisability.TheRMDQisreliablebutthismanuscriptdidnotministered&completedatalltimeintervalsin193Thesechangesappearedtobereflectedinthedis-assessitsresponsivenesstoastandardmeasureinsta-patients.Correlationwasqualitativelydonew/abilityquestionnaire.Absencefromworkappear-tisticalfashion.back-to-workstatus.edtocorrelatelesswellasonly8%ofemployedwereunabletowork4wksafteracutelumbago.Waddell&Main,1984I160patientsw/12wksoflumbago(chronic)w/se-DisabilityasdeterminedbyfunctionaloutcomeonWaddellScaledescribesfunctionaldisabilityw/chron-veritystudiedbya9-categorydisabilityindex&questionnairehadareliabilityϾ0.80&correlatedicLBP.All9scalescorrelatew/finalscore(contentphysicalcharacteristics.Reliabilitydeterminedus-w/theODI(r=0.70).Forphysicalcharacteristicsvalidity)&thescaleisreliable.Italsohasconstructingasubgroupof30patients.(lumbarflexion,straightlegraising,rootcompres-validityasitcorrelatesw/ODI.sionsigns)reliabilitywasϾ0.90.Deyo,1986I136patientswhowereexaminedinaclinicforachiefReliabilityforbothscaleswas␬Ͼ0.80inpatientsTheSIP&themodifiedRMDQ(shorter)arereliablecomplaintoflumbago.Evaluationwasdoneusing(10)whohadnochangeinpain.Forpatientswhoscalesfortheassessmentoflumbago,whichseemtoSIP&themodifiedRMDQScale(shortenedver-didnotresumefullactivity(47),thereliabilityfollowthephysicaldimensionoffunctionaldisability.sionofSIP)initially&3wkslater.was␣Ͼ0.60.AstrongcorrelationexistedbtwnThemodifiedRMDQislesswellsuitedtofollowthethescales(r=0.85)&betweenthephysicaldi-psychosocialdimensionoffunctionaldisability.mensionoftheSIP&themodifiedRMDQ(r=0.89).ThemodifiedRMDQcorrelatedlesswellw/thepsychosocialdimensionoftheSIP(r=0.56).Lawlis,etal.,1989I143patientsoverall(24normal,15chroniclumbagoExternalreliabilitywas␬Ͼ0.90.ConstructvalidityTheDPQisareliabletestinassessingchronicLBP&butworking,104chroniclumbagoundergoingin-wasshownbycorrelationofthe1st2categoriesappearsresponsiveindefiningdifferencesbtwnpatienttherapy).FunctionalassessmentperformedofDPQw/functionalcapacityscoresrelatingtopatientsw/chroniclumbago&thosew/o.usingtheDPQwhichassessesdailyactivities,workthephysicaldemandsofwork.Responsivenesswas&leisureactivities,anxiety/depression,&socialassessedbycomparingDPQscoresinthe104interest.Reliabilitytestedon15chronicpainpatientschroniclumbagopatientstothe24normalpatients.&13normalpatients.DPQscoresweresignificantlyhigherintheformer.continuedSpineJune2005 5/24/05 10:42 AM Page 641
  6. 6. D. K. Resnick, et al.642 J. Neurosurg: Spine / Volume 2 / June, 2005TABLE1ContinuedAuthors&YearClassDescriptionResultsConclusionsManniche,etal.,1994I58patientswhounderwentlumbardiscopweresur-TheLBPRscalecomprised60pointsforpain,30forTheLBPRScalecombineselementsofphysicalfunc-veyed14–60mospostop.Theassessmentwasanleveloffunction,&40forphysicalimpairment.tion,painintensity,&overalldisability.ItisareliableLBPRscalethatexaminedphysicalimpairment,dis-Interraterreliabilitywas␬Ͼ0.95.Usingcontin-indicatorofdysfunction&appearsvalidcomparedw/ability,&painintensity.Comparisonwasdonegencytables,thescalecorrelatedwiththedoctor’sobjectivemeasures(doctor’sassessment)&subjec-againstadoctor’sglobalassessment&apatient’sassessmentandpatient’sassessment(pϽ0.00005).tive/satisfactionmeasures(patient’sassessment).globalassessment.Ruta,etal.,1994I354patientsw/lumbagoinitiallyexaminedinclinic&183patientshadnoclinicalchanges&underwentThisLBPscaleisareliable&validindicatorofthesurveyedshortlythereaftertoassessfunctionaldis-externalreliabilitytesting(␬Ͼ0.90).Thequestion-functionaldisabilityrelatingtolumbago.Nousageability.273patientswereretestedforreliabilityofnairecorrelatedwellw/all8domainsoftheSF-36describedinthesettingoflumbarfusion.Noacuitywhom183reportednochangeinclinicalseverity.usinglinearregression(pϽ0.001)&w/percep-givenforthelumbago.CorrelationtotheSF-36generalhealthprofilewastionsofdiseaseseverity.doneforconstructvalidity.Salen,etal.,1994I1445patientsweredividedinto3groups:1092vol-ExternalreliabilityfortheDRIwas␬Ͼ0.80.ThereTheDRIisareliable,valid,&responsivemeasureinunteercontrols,306w/axialskeletalpain,&47w/wasacorrelationtotheFSQ.TheDRIwasres-patientsw/axialskeletalpain.jointpain.PatientswereevaluatedusingtheDRIponsiveindetectingimprovementafterjointre-&anFSQ.placement.Harper,etal.,1995I150patientsweredividedinto3groups(GroupI:Externalreliabilityinall3groupswas␬Ͼ0.90.In-TheCBSQisareliable&validmeasurefordeterminingchroniclumbagoϾ4wks/disabled;GroupII:acuteternalreliabilitywas␣Ͼ0.80.TherewasastrongthefunctionaldisabilityassociatedwithLBP.Nolumbago/working;GroupIII:normal).EvaluationofcorrelationbtwneachcategoryinCBSQ&itssim-testingofresponsivenesswasundertaken.functionaldisabilitywasdoneusingtheCBSQ&ilarcategoryintheSIP(r=0.56–0.72).Finally,theSIP.TheCBSQtests11categoriesoffunctionalCBSQscoresappearedresponsivew/higherscoresdisability.Test–retestcorrelation&correlationbtwninthemoreseverelyaffectedgroups.tCBSQandSIPwasdoneusingthePearsoncor-relationtest.Kopec,etal.,1995I242patientswithahistoryoflumbagoinQuebec.80%Externalreliabilitywas␬Ͼ0.90w/internalconsis-TheQPDSissuitableforthereliablefunctionalmea-hadpriorlumbagow/29%receivingcompensation.tencyof␣Ͼ0.90.ConstructvaliditywasshownsurementofLBP.Patientswereassessedforfunctionaldisabilityus-byastrongcorrelationinthisfunctionalindexw/ingtheQPDS.Reliabilitywasexaminedina98-theODI(r=0.80),RMDQ(r=0.77),&SF-36patientsamplew/in1–14daysafterinitialsurvey.(r=0.72).ConstructvaliditywasdonebycomparingresultstofunctionalscalesofODI,RMDQ,&SF-36.Daltroy,etal.,1996I206patientsin6orthopedicpracticeswereevaluated.External&internalreliabilitywerestrong(␬Ͼ0.90)TheNASSLSOAisavalid&reliableoutcomemeasurePatientswereinseveralcategoriesincludingthosewhenassessedin64patients.Themeasurewasforfunctionalevaluationofthelumbarspine.w/LBP&sciatica.Alsoincludedwerepatientswhovalidcomparedw/knowninstruments.underwentlumbardecompressionbutnotfusion.Stucki,etal.,1996I193patientsw/lumbardegenerativestenosisundergo-23/193studiedforreliabilityw/␬Ͼ0.80.InternalThisoutcomequestionnairewasreliableinlumbarsten-ingdecompression.Prospectivemulticenterstudyofconsistency␣Ͼ0.80;130/193studiedforrespon-osispatientswhounderwentop&hadconstructvalid-self-administeredoutcomemeasureassessedw/insiveness.Responsive&validover6mostodetectitycomparedw/establishedscale&wasresponsive6mos.Likertresponsescalesusedindomainsofimprovementpostop.indetectionofdifferencesw/in6mosforfunctionalphysicaldysfunction,symptomseverity,&satisfac-improvement.tion.Resultscomparedw/SIP&VAS.Fujiwara,etal.,2003I97patientsobservedclinicallyw/LBP&followedTest–retestreliabilitywas␬Ͼ0.90whenpatientsTheJOAisareliable&validindicatorofLBP.usingJOA,ODI,andRMDQ.Correlationwascal-(15)orphysicians(30)didrepeatmeasurements.culatedbtwnthesemeasures&externalreliabilityStrongcorrelationwasobservedbtwnJOA&wasassessedbyrepeatedphysician&patientob-ODI&RMDQ.servation.Luo,etal.,2003I2520patientsw/LBP;506patientsassessedover3–6ExternalreliabilityoftheSF-12wasperformedbyTheSF-12iscapableofassessing&followingLBPmos.SF-12surveywasused&comparedw/subjec-Ware,etal.,inadifferentpatientgroup;however,reliably.tivequantificationofLBPintensity.internalreliability&responsivenesswasfoundinthisstudy.*LBP=low-backpain;NASSLSOA=NorthAmericanSpineSocietyLumbarSpineOutcomeAssessment;RA=rheumatoidarthritis.SpineJune2005 5/24/05 10:42 AM Page 642
  7. 7. J. Neurosurg: Spine / Volume 2 / June, 2005Functional Outcome643internal consistency was greater than 0.90. Self-assess-ment of sickness and dysfunction had a reliability greaterthan 0.60. The SIP appeared to correlate (Ͼ 0.50) with theself-assessment of sickness and dysfunction. Deyo9usedthe SIP and a modified RMDQ when evaluating 136 pa-tients with a chief complaint of low-back pain at an initialindex visit and 3 weeks later. Reliability was examined in10 patients who claimed no interval improvement in painand in 47 patients who did not resume full activity. Forpatients with no change in pain, the correlation was great-er than 0.80. In those patients who may have improved butdid not resume normal activity, reliability was greater than0.60. A strong correlation was observed between the SIPand the modified RMDQ (r = 0.85). The physical dimen-sion of the SIP (r = 0.89) correlated more strongly with theRMDQ than the psychosocial dimension (r = 0.56). TheSIP appears to be a reliable and valid measure of the se-verity of low-back pain in the acute phase.Million and colleagues27assessed 19 patients with chron-ic low-back pain by using a VAS examining 15 subjectivevariables reflecting its severity. External reliability amongand within observers was greater than 0.90. To determinevalidity, they compared their results with physical mea-surements of spinal movements and straight leg raising.These objective assessments had a reliability greater than0.90 and correlated with the Million Scale. After bracingwith a rigid support, low-back pain improved clinicallyand this responsiveness was detected by the Million Scale.The Waddell–Main Disability Index was used to evaluatechronic low-back pain (duration Ͼ 12 weeks) in a 160-pa-tient cohort.37Reliability in this study was evaluated in arandom subgroup of 30 patients. Measures were also ob-tained of objective physical characteristics including lum-bar flexion, straight leg raising, and root compression signs.The external reliability on the Waddell–Main Disability In-dex was greater than 0.80, and its validity was establishedby a strong correlation with the ODI (r = 0.70). The physi-cal characteristics, when evaluated for objective reliability,had a correlation greater than 0.80.Using the DPQ, Lawlis and colleagues23studied 143 pa-tients of whom 119 had chronic low-back pain. Fifteenpatients in this group were working, whereas the remain-ing 104 were undergoing inpatient therapy. Twenty-fourhealthy volunteers served as controls. The DPQ was usedto assess daily activities, work/leisure activities, anxiety/depression, and social interest. Reliability was tested in 15patients with chronic back pain and 13 controls. Externalreliability was greater than 0.90. Construct validity wasshown through a positive correlation to other assessmentsof functional capacity relating to the physical demands ofwork. The DPQ was responsive to differences betweenpatients with chronic low-back pain and controls.Ruta, et al.,32devised an outcome measure based onquestions commonly used in the clinical assessment ofpatients with low-back pain. A total of 354 patients withlow-back pain seen by primary and specialty practitionerswere studied. Within this group, 273 patients were testedfor reliability. One hundred eighty-three reported no clin-ical changes over a 2-week interval. External reliabilitywas tested in these 183 patients with correlations greaterthan 0.90. Validity was demonstrated by a strong correla-tion (p Ͻ 0.001 on regression) with the SF-36 generalhealth assessment. Harper and colleagues19examined 150patients in three subgroups (chronic low-back pain [50cases], acute lumbago [49 cases], and control [51 cases]).They employed the CBSQ, which evaluated 11 categoriesof functional disability and compared results with those ofthe SIP. External reliability for the CBSQ was greater than0.90, with internal reliability greater than 0.80. A strongcorrelation was observed between each category in theCBSQ and its similar category in the SIP (r = 0.56–72), andthe CBSQ appeared responsive in distinguishing the sever-ity of dysfunction among the three groups of patients.Several other groups undertook studies on the functionalassessment of chronic low-back pain. Using the QPDS,Kopec, et al.,22analyzed 242 patients with a history ofchronic low-back pain. Twenty-nine percent of this groupwere disabled and receiving compensation. This scale con-tains 48 items assessing the difficulty in simple daily activ-ities pertaining to domains relevant to low-back pain. Re-liability was gauged using a random sample (98 cases) whowere retested after 14 days. External reliability was greaterthan 0.90, with an internal consistency coefficient greaterthan 0.90. Construct validity was determined by a strongcorrelation with the ODI (r = 0.80), RMDQ (r = 0.77), andSF-36 (r = 0.72) Scales. Using the LBPR scale, Mannicheand colleagues26surveyed 58 patients 14 to 60 monthsafter they underwent lumbar disc surgery. This scale com-prises 60 points for back and leg pain, 30 points for levelof function, and 40 points for physical impairment. Exter-nal reliability had a coefficient greater than 0.95. Validitywas determined by dichotomizing the scale into good andbad outcomes. The mean score of the study population was39, and therefore a value greater than 39 implied greaterdysfunction than the mean. The results on the LBPR Scalecorrelated (p Ͻ 0.00005) with a Global Assessment Scale(a graded evaluation tool) performed by both patient andphysician.Stucki, et al.,35evaluated 193 patients with degenerativelumbar stenosis from multiple centers who were to under-go lumbar decompression. A functional survey was under-taken preoperatively and 6 months after surgery. Interob-server reliability was studied in a random sample of 23patients. Correlation (␬) was greater than 0.80 in this group.Internal consistency was greater than 0.80. This lumbaroutcome scale was responsive to functional improvementin this cohort of patients when reassessed 6 months follow-ing surgery. Comparison to the SIP and the VAS for painconfirmed the validity of this instrument in detecting over-all dysfunction associated with lumbar stenosis.Bernstein and colleagues2followed 291 patients withchronic low-back pain by using the 90-item SymptomChecklist, which measures psychological dysfunction. Ithas nine major scales with one common factor—generalpsychological discomfort. The somatization scale coversgeneral physical discomfort. The reliability of this check-list was not reported in this study, but validity was ascer-tained by comparison with the Minnesota Multiphasic In-ventory and the McGill Pain Inventory. In this group ofpatients, the scale had a high correlation with the Minne-sota Multiphasic Inventory and McGill Inventory scalesfor detecting general discomfort; however, external relia-bility was not reported. In a 5-year period, Greenough andFraser16studied 300 patients with low-back pain by usinga Low-Back Outcome Score that examined 13 functionalfactors related to pain. Comparison was made to the ODISpineJune2005 5/24/05 10:42 AM Page 643
  8. 8. and Waddell–Main scales. Despite a statement that exter-nal reliability was studied, no mention was made of thestatistical analysis in their study. This scale had a high cor-relation with the ODI (Ϫ0.87; p Ͻ 0.001) and Waddell–Main scale (Ϫ0.74; p Ͻ 0.001). Moffroid and colleagues28assessed 115 patients undergoing physical therapy refer-red for low-back pain, 112 asymptomatic volunteers wereused as a control group. The physical capabilities of bothgroups were quantified using the National Institute for Oc-cupational Safety and Health Low Back Atlas score. Al-though external reliability was described, it was not spe-cifically reported in this study. The authors did find clustersof patients with imbalances in muscle strength and symme-try. Those patients were more apt to suffer from low-backpain.General health may be measured in addition to low-back pain. In addition to the use of the SIP as a generalhealth measure, Brazier and colleagues3studied the SF-36Scale in 1582 patients in a general medical practice. TheSF-36 Scale focuses on functional status, general well-ness, and an overall assessment of health in eight domainsby asking 36 questions. Results were compared for valid-ity with the Nottingham Scale. In the general population,the external reliability coefficient was greater than 0.60.Construct validity was determined through a correlationwith the Nottingham Scale (r Ͼ 0.50). Ware and col-leagues38used regression methods to shorten the SF-36 toa 12-item format (SF-12) focusing on physical and mentalaspects. Reliability in an initial evaluation of two differentsets of patients was strong (␬ Ͼ 0.80). Luo and col-leagues25used the SF-12 in 2520 patients with low-backpain. Although no external reliability was performed inthis setting, internal consistency was sound, and the SF-12appeared valid and responsive to changes in patients withlow-back pain.Salen, et al.,33assessed 1092 healthy volunteers andcompared observation with 306 patients with axial skele-tal pain or 47 with joint pain by using a DRI. External reli-ability for this group was greater than 0.80. The DRI wasvalid with correlation to the FSQ. The DRI was respon-sive in detecting improvement after joint replacement.Examples of the Application of Functional Assessments toLumbar FusionThe appropriateness of an outcome instrument designedto assess low-back pain does not necessarily generalizeto the assessment of patients treated with lumbar spinalfusion procedures. Despite this fact, these same outcomemeasures have been used to assess outcome followinglumbar fusion procedures. In an attempt to correct thisapparent deficiency, many investigators have used multi-ple outcome instruments for correlation.Several groups have used more formalized methods ofassessing patient outcome. Moller and Hedlund29studied111 patients with isthmic spondylolisthesis and a 1-yearhistory of back or leg pain. Patients were randomized tosurgery (80 cases) or exercise (34 cases). Evaluation wascompleted at 1 and 2 years by using the DRI and a patientassessment survey involving broad categories (much bet-ter, better, unchanged, or worse). In this patient popula-tion, the DRI appeared responsive with improvement inthe surgical group at 12 and 24 months (p Ͻ 0.0001,Mann–Whitney U-test). Similarly, the broad patient assess-ment survey revealed that a higher proportion of “good”responses occurred in the surgery group (p Ͻ 0.01). In asimilar cohort study, Christensen and colleagues6followed129 patients with chronic low-back pain and either isthmicspondylolisthesis, primary lumbar degeneration, or second-ary lumbar degeneration. Comparison was made betweenposterior fusion with and without instrumentation by usingthe DPQ and LBPR Scale in a 5-year period. Patients inboth groups improved significantly from their preopera-tive status on the DPQ during this period. With the excep-tion of patients with isthmic spondylolisthesis, no differ-ences were observed between groups when using the DPQor LBPR Scale. For patients with isthmic spondylolisthe-sis, fusion without instrumentation resulted in significant-ly better results as measured by the DPQ.In a different cohort study, Fritzell and colleagues14studied 294 patients with L4–S1 disc degeneration andlow-back pain who underwent surgical (222) or expectant(72) management during a 6-year period. Evaluation wascompleted at 6, 12, and 24 months by using the ODI,Million, and General Function Score Scales. Disabilitysignificantly decreased in the surgical group over a 2-yearperiod when assessed using all of these scales (p Ͻ 0.02).Using a general, subjective assessment, 63% in the surgi-cal group indicated they were better or much better com-pared with 29% in the nonsurgical group (p Ͻ 0.0001).Burkus, et al.,4reported on 46 patients randomized toanterior interbody fusion with or without bone morpho-genetic protein–2. Outcome was recorded over a 24-monthperiod by using the ODI, SF-36, and satisfaction scales.Neurological function, satisfaction, and general healthmeasures were no different between groups. The ODIscore indicated an improvement in the bone morphogen-etic protein–2 group as early as 3 months after surgery.These outcome measures were responsive to low-backpain after lumbar fusion, and the use of multiple outcomemeasures conferred apparent validity.Other Outcome MeasuresTurner and colleagues36undertook a metaanalysis of alllumbar fusion Medline literature published between 1966and 1991. Studies were required to have a minimum 1-year follow-up period and classification of clinical out-come as satisfactory or unsatisfactory in at least 30 patients.Forty-seven articles met their inclusion criteria. No ran-domized trials were identified at that time. A mean of 68%of the patients had a satisfactory outcome (range 16–95%).Substratification revealed outcomes of excellent/good in66% (range 16–93%), fair in 22% (range 5–68%), and poorin 13% (range 2–54%). No defined criteria were reportedfor external reliability. Their analysis demonstrates thatoutcomes may be dichotomized into broad categories toassess overall outcome following lumbar fusion.Patient satisfaction has been used as an outcome mea-sure for patients undergoing lumbar fusion. Patient satis-faction surveys are frequently used in the setting of retro-spective series because preintervention data may not beavailable. Patient satisfaction is easily surveyed but isdependent on multiple external factors independent of thesurgical procedure. Furthermore, satisfaction outcomemeasures are hampered by the inherent inability to measureD. K. Resnick, et al.644 J. Neurosurg: Spine / Volume 2 / June, 2005SpineJune2005 5/24/05 10:42 AM Page 644
  9. 9. responsiveness. The validity of satisfaction measures hasbeen examined but their external reliability has not.Slosar and colleagues34followed 141 patients who un-derwent circumferential lumbar fusion. A satisfaction sur-vey was used as a follow-up instrument, as was return toemployment. Patients were asked if: 1) surgery met theirexpectations; 2) surgery improved their condition; 3) sur-gery improved their condition but they would not repeat it;and 4) surgery worsened their condition. One hundred thir-ty-three patients were followed for more than 37 months.The outcomes were classified as follows: 10.5% in Cate-gory 1, 51.1% in Category 2, 19.5% in Category 3, and18.8% in Category 4. Christensen and colleagues5followed148 patients who underwent posterior lumbar fusion withor without supplemental anterior interbody fusion. Satis-faction surveys and the DPQ and LBPR Scale were used.In addition to improvements on the LBPR Scale and DPQ,satisfaction was high in both groups, with 77% of patientsin the posterior fusion group and 79% of patients in the cir-cumferential fusion group stating they would undergo sur-gery again if indicated.In a study of 388 Workers’ Compensation patients inWashington state, Franklin and colleagues13undertook anassessment of broad satisfaction surveys. Simple surveysexamined back and leg pain, QOL, and the decision to un-dergo surgery at 2 years following lumbar fusion. Patientswere dichotomized into two outcome groups: poor (re-ceiving Workers’ Compensation) and good (not receivingWorkers’ Compensation) at 2 years. There was a higher in-cidence of poor outcomes among those who stated thatback or leg pain was worse than expected (76% comparedwith 54%; p Ͻ 0.0003) and in those whose QOL was nobetter or worse than expected (69% compared with 34%;p Ͻ 0.0001). There was a lower incidence of poor out-comes in patients who would undergo surgery again for thesame indications (52% compared with 80%; p Ͻ 0.0001).Although patient satisfaction surveys are easy and areintuitively valuable, they have never been validated andthe responsiveness of such measures cannot be measured.Furthermore, wide discrepancies exist when results ofpatient satisfaction surveys are compared with validatedoutcome measures. These inadequacies limit their abilityto provide high-quality medical evidence for or againstany treatment modality.SummaryFunctional disability secondary to acute low-back pain,chronic low-back pain, lumbar stenosis, and lumbar discdisease may be reliably and validly assessed using func-tional outcome surveys that are valid, reliable, and respon-sive. Outcome instruments supported by Class I and ClassII medical evidence for the evaluation of low-back paininclude the Spinal Stenosis Survey of Stucki, Waddell–Main, RMDQ, DPQ, QPDS, SIP, Million Scale, LBPRScale, ODI, and CBSQ. Many of these outcome measureshave been applied to patients who have been treated withlumbar fusion for degenerative lumbar disease and haveproven to be valid and responsive; however, the reliabilityof these instruments has never been specifically assessed inthe lumbar fusion patient population. Patient satisfactionsurveys have been used to measure outcome followinglumbar fusion. Their usefulness resides in their insight in-to patient attitudes toward the treatment experience but islimited because of their inability to measure responsive-ness and the lack of information on their reliability.Key Issues for Future InvestigationAlthough the functional outcome instruments discussedin this review appear valid and responsive in the low-backpain patient population, their external reliability has notbeen confirmed in the clinical setting of lumbar fusion.This may be important for the comparison of differentlumbar fusion techniques. Another key issue appears to bethe timing of administration of the outcomes instruments.The aforementioned functional outcome measures appearto be responsive both initially and over a few years. Whet-her the benefits associated with any sort of interventionfor low-back pain are durable beyond this period has notbeen established.References1. Bergner M, Bobbitt RA, Carter WB, et al: The Sickness ImpactProfile: development and final revision of a health status mea-sure. Med Care 19:787–805, 19812. Bernstein IH, Jaremko ME, Hinkley BS: On the utility of theSCL-90-R with low-back pain patients. Spine 19:42–48, 19943. Brazier JE, Harper R, Jones NM, et al: Validating the SF-36health survey questionnaire: new outcome measure for primarycare. BMJ 305:160–164, 19924. Burkus JK, Transfeldt EE, Kitchel SH, et al: Clinical and radio-graphic outcomes of anterior lumbar interbody fusion using re-combinant human bone morphogenetic protein-2. Spine 27:2396–2408, 20025. Christensen FB, Hansen E, Eiskjaer SP, et al: Circumferentiallumbar spinal fusion with Brantigan cage versus posterolateralfusion with titanium Cotrel-Dubousset instrumentation: a pros-pective, randomized clinical study of 146 patients. Spine 27:2674–2683, 20026. Christensen FB, Hansen ES, Laursen M, et al: Long-term func-tional outcome of pedicle screw instrumentation as a supportfor posterolateral spinal fusion. Spine 27:1269–1277, 20027. Cronbach LJ: Coefficient alpha and the internal structure oftests. Psychometrika 16:297–334, 19518. Daltroy LH, Cats-Baril W, Katz JN, et al: The North AmericanSpine Society Lumbar Spine Outcome Assessment Instrument:Reliability and Validity Tests. Spine 21:741–748, 19969. Deyo RA: Comparative validity of the sickness impact profileand shorter scales for functional assessment in low-back pain.Spine 11:951–954, 198610. Deyo RA, Andersson G, Bombardier C, et al: Outcome mea-sures for studying patients with low back pain. Spine 19 (18Suppl):S2032–S2036, 199411. Deyo RA, Diehr P, Patrick DL: Reproducibility and responsive-ness of health status measures. Statistics and strategies for evalu-ation. Control Clin Trials 12 (4 Suppl):S142–S158, 199112. Fairbank JC, Couper J, Davies JB, et al: The Oswestry low backpain disability questionnaire. Physiotherapy 66:271–273, 198013. Franklin GM, Haug J, Heyer NJ, et al: Outcome of lumbar fu-sion in Washington State workers’ compensation. Spine 19:1897–1904, 199414. Fritzell P, Hagg O, Wessberg P, et al: 2001 Volvo Award Win-ner in Clinical Studies: Lumbar fusion versus nonsurgical treat-ment for chronic low back pain: a multicenter randomizedcontrolled trial from the Swedish Lumbar Spine Study Group.Spine 26:2521–2534, 200115. Fujiwara A, Kobayashi N, Saiki K, et al: Association of the Jap-anese Orthopaedic Association score with the Oswestry Dis-J. Neurosurg: Spine / Volume 2 / June, 2005Functional Outcome645SpineJune2005 5/24/05 10:42 AM Page 645
  10. 10. ability Index, Roland-Morris Disability Questionnaire, andShort-Form 36. Spine 28:1601–1607, 200316. Greenough CG, Fraser RD: Assessment of outcome in patientswith low-back pain. Spine 17:36–41, 199217. Greenough CG, Peterson MD, Hadlow S, et al: Instrumentedposterolateral lumbar fusion. Results and comparison with ante-rior interbody fusion. Spine 23:479–486, 199818. Hadley MN, Walters BC, Grabb PA: Guidelines for the man-agement of acute cervical spine and spinal cord injuries. Neu-rosurgery 50 (Suppl):S2–S6, 200219. Harper AC, Harper DA, Lambert LJ, et al: Development andvalidation of the Curtin Back Screening Questionnaire (CBSQ):a discriminative disability measure. Pain 60:73–81, 199520. Katz JN: Lumbar spinal fusion. Surgical rates, costs, and com-plications. Spine 20 (24 Suppl):S78S–S83, 199521. Kopec JA, Esdaile J: Functional disability scales for back pain.Spine 20:1943–1949, 199522. Kopec JA, Esdaile J, Abrahamowicz M, et al: The Quebec BackPain Disability Scale. Measurement properties. Spine 20:341–352,199523. Lawlis GF, Cuencas R, Selby D, et al: The development of theDallas Pain Questionnaire. An assessment of the impact ofspinal pain on behavior. Spine 14:511–516, 198924. Leclaire R, Blier F, Fortin L, et al: A cross-sectional study com-paring the Oswestry and Roland-Morris Functional Disabilityscales in two populations of patients with low back pain of dif-ferent levels of severity. Spine 22:68–71, 199725. Luo X, Lynn George M, Kakouras I, et al: Reliability, validity,and responsiveness of the short form 12-item survey (SF-12) inpatients with back pain. Spine 28:1739–1745, 200326. Manniche C, Asmussen K, Lauritsen B, et al: Low Back PainRating scale: validation of a tool for assessment of low backpain. Pain 57:317–326, 199427. Million R, Hall W, Nilsen KH, et al: Assessment of the progressof the back-pain patient. 1981 Volvo Award in Clinical Scien-ces. Spine 7:204–208, 198228. Moffroid MT, Haugh LD, Henry SM, et al: Distinguishablegroups of musculoskeletal low back pain patients and asymptom-atic control subjects based on physical measures of the NIOSHLow Back Atlas. Spine 19:1350–1358, 1994 (Erratum in Spine19:2137, 1994)29. Moller H, Hedlund R: Surgery versus conservative managementin adult isthmic spondylolisthesis—a prospective, randomizedstudy: part 1. Spine 25:1711–1715, 200030. Roland M, Morris R: A study of the natural history of back pain.Part I: development of a reliable and sensitive measure of dis-ability in low-back pain. Spine 8:141–144, 198331. Roland M, Morris R: A study of the natural history of low-backpain. Part II: development of guidelines for trials of treatmentin primary care. Spine 8:145–150, 198332. Ruta DA, Garratt AM, Wardlaw D, Russell IT: Developing avalid and reliable measure of health outcome for patients withlow back pain. Spine 19:1887–1896, 199433. Salen BA, Spangfort EV, Nygren AL, et al: The DisabilityRating Index: an instrument for the assessment of disability inclinical settings. J Clin Epidemiol 47:1423–1435, 199434. Slosar PJ, Reynolds JB, Schofferman J, et al: Patient satisfactionafter circumferential lumbar fusion. Spine 25:722–726, 200035. Stucki G, Daltroy L, Liang MH, et al: Measurement propertiesof a self-administered outcome measure in lumbar spinal steno-sis. Spine 21:796–803, 199636. Turner JA, Ersek M, Herron L, et al: Patient outcomes afterlumbar spinal fusions. JAMA 268:907–911, 199237. Waddell G, Main CJ: Assessment of severity in low-back dis-orders. Spine 9:204–208, 198438. Ware JE, Kosinski M, Keller SD: A 12-Item Short-Form HealthSurvey: construction of scales and preliminary tests of reliabil-ity and validity. Med Care 34:220–233, 1996Manuscript received December 7, 2004.Accepted in final form March 22, 2005.Address reprint requests to: Daniel K. Resnick, M.D., Depart-ment of Neurological Surgery, University of Wisconsin MedicalSchool, K4/834 Clinical Science Center, 600 Highland Avenue,Madison, Wisconsin 53792. email: Resnick@neurosurg.wisc.edu.D. K. Resnick, et al.646 J. Neurosurg: Spine / Volume 2 / June, 2005SpineJune2005 5/24/05 10:42 AM Page 646
  11. 11. RecommendationsStandards. There is insufficient evidence to recommenda standard for assessment of economic outcome followinglumbar fusion for degenerative disease.Guidelines. There is insufficient evidence to recom-mend a guideline for assessment of economic outcomefollowing lumbar fusion for degenerative disease.Options. It is recommended that valid and responsiveeconomic outcome measures be included in the assess-ment of outcomes following lumbar fusion surgery fordegenerative disease. Return-to-work rates and termina-tion of disability compensation are two such measures. Itis recommended that cost analyses related to lumbarspinal fusion include perioperative expenses as well as ex-penses associated with long-term care, including thoseincurred in both the operative and nonoperative settings.RationaleLumbar fusion is commonly performed as an adjunct tothe surgical treatment of patients with low-back pain dueto degenerative lumbar disease. Using data from the Na-tional Hospital Discharge Survey, both Deyo, et al.,4andDavis3observed a dramatic increase in the frequency oflumbar fusion procedures in the 1980s. Lumbar fusion hasbeen undertaken in the setting of degenerative disc disease,spinal stenosis, spondylolisthesis, and degenerative scolio-sis and is commonly supplemented with internal fixationinvolving a variety of devices. As the frequency and com-plexity of lumbar fusion surgery increases, there is a ten-dency for costs and complication rates to follow.9In a timeof contracting hospital resources, it is important to under-stand the economic impact of lumbar fusion. The purposeof this review is to examine the economic impact of lum-bar fusion for degenerative lumbar spine disease asassessed by cost, complication rates, and rates of reopera-tion. These expenses of lumbar fusion must be contrastedwith the return-to-work rate and the potential for im-proved productivity following treatment. These end pointswill be examined as economic outcome measures follow-ing lumbar fusion.Search CriteriaA computerized search of the National Library of Me-dicine database of the literature published between 1966and 2001 was performed. A search using the subject head-ing “lumbar fusion” yielded 3708 citations. The followingsubject headings were combined: “lumbar fusion and out-comes.” Approximately 204 citations were acquired. Onlycitations in English were selected. A search of this setof publications with the key words “employment status,”“mortality,” “medical care costs,” “cost containment/com-J. Neurosurg: Spine / Volume 2 / June, 2005J Neurosurg: Spine 2:647–652, 2005Guidelines for the performance of fusion proceduresfor degenerative disease of the lumbar spine.Part 3: assessment of economic outcomeDANIEL K. RESNICK, M.D., TANVIR F. CHOUDHRI, M.D., ANDREW T. DAILEY, M.D.,MICHAEL W. GROFF, M.D., LARRY KHOO, M.D., PAUL G. MATZ, M.D.,PRAVEEN MUMMANENI, M.D., WILLIAM C. WATTERS III, M.D., JEFFREY WANG, M.D.,BEVERLY C. WALTERS, M.D., M.P.H., AND MARK N. HADLEY, M.D.Department of Neurosurgery, University of Wisconsin, Madison, Wisconsin; Department ofNeurosurgery, Mount Sinai Medical School, New York, New York; Department of Neurosurgery,University of Washington, Seattle, Washington; Department of Neurosurgery, Indiana University,Indianapolis, Indiana; Departments of Orthopedic Surgery and Neurosurgery, University ofCalifornia at Los Angeles, California; Department of Neurosurgery, University of Alabama atBirmingham, Alabama; Department of Neurosurgery, Emory University, Atlanta, Georgia;Bone and Joint Clinic of Houston, Texas; and Department of Neurosurgery, Brown University,Providence, Rhode IslandKEY WORDS • fusion • lumbar spine • practice guidelines • treatment outcome •economic outcome647Abbreviations used in this paper: CI = confidence interval;LOS = length of stay; QOL = quality of life; RR = relative risk.SpineJune2005 5/24/05 10:42 AM Page 647
  12. 12. parison,” or “cost effectiveness” resulted in 58 matches.Titles and abstracts of the articles were reviewed. Clinicalseries dealing with adult patients who had lumbar fusionfor degenerative disease were selected. Additional refer-ences were culled from the reference lists of remainingarticles.Among the articles reviewed, 13 studies were includedthat dealt with lumbar fusion, complication rates, reopera-tion rates, and costs. Six of these articles were cohort stud-ies that examined the economic impact of lumbar fusioncompared with surgery for degenerative lumbar diseasethat did not involve fusion. One article was a cohort studyinvestigating fusion with and without fixation. Two stud-ies examined the cost benefit or cost effectiveness of lum-bar fusion compared with decompression alone. The re-maining study examined the responsiveness of returningto work as an economic indicator in a large series. Thesearticles are summarized in Table 1.Scientific FoundationOne of the more difficult results to ascertain followinga medical or surgical treatment is economic outcome. Typ-ical medical economic analyses seek to ascertain whethera given treatment-related benefit accrues in light of theexpenditures required to provide that treatment. With re-gard to lumbar fusion procedures, benefits from treatmentmay include an overall improvement in low-back pain andfunction, an increased return-to-work rate, and/or improv-ed patient satisfaction. The expenses of the procedures arethe measured costs of the surgery, the devices implanted,and operative time. Other measurable outlays include thecost of complications and time and expenses associatedwith reoperation. Deyo and colleagues4examined dataconcerning lumbar spinal disease and lumbar spinal fu-sion from the National Hospital Discharge Survey be-tween 1979 and 1987. In addition to a 200% increase inspinal fusion procedures performed during this period,the authors reported significant regional variations in theperformance of lumbar fusion procedures as reflected bya ninefold regional variation in frequency between thenortheastern US (four/100,000) and the western US (35/100,000). Because of the increasing incidence of lumbarfusion procedures in the treatment of degenerative spinedisease, it is important to examine the economic impact oflumbar fusion as a specific outcome measure.Costs, Complications, Hospitalizations, and ReoperationsMalter and colleagues12performed a population-basedstudy of patients who underwent lumbar surgery for de-generative disease in Washington state in 1988. The studywas not prospective, nor was it clear that all patients wereeligible for all therapies. Using diagnosis and procedurecodes from the Washington State Department of Health’scomputerized system, the authors obtained data on 6376patients of whom 1041 underwent lumbar fusion. Rates ofreoperation, complications, and associated costs (in 1988US dollars) were examined through the next 5 years. Thecomplication rates associated with lumbar arthrodesis pro-cedures were 18% compared with a 7% complication ratefollowing lumbar surgery without arthrodesis (chi-squaretest, p Ͻ 0.001). The LOS was significantly longer forfusion-treated patients (7 days compared with 5.1 days;p Ͻ 0.001). In 1988 dollars, hospital costs averaged $7101per patient treated with fusion and $4161 per patient treat-ed without fusion (p Ͻ 0.001). These authors examinedreoperation rates to determine if fusion reduced the needfor repeated lumbar surgery within 5 years. Reoperationrates were similar between those treated with fusion (RR1.1; 95% CI 0.9–1.3) and those not. Because the indica-tions for surgery were not examined, the only conclusionsthat could be drawn from this study were that lumbarfusion procedures are associated with increased costs andcomplications.Using similar methods and a hospital discharge registryin Washington state, Deyo and colleagues5examined18,122 hospitalizations for lumbar surgery between 1986and 1988. The majority (84%) of cases requiring surgeryinvolved spinal stenosis or disc displacement. Excludedwere cases involving malignant lesions, infection, or frac-tures. Approximately 15% of patients in this cohort under-went arthrodesis in addition to decompression. The report-ed mortality rate was less than 1%. The complication ratewas 17.4% among patients treated with fusion comparedwith a 7.6% rate for those with lumbar disease treated sur-gically without fusion (chi square test, p Ͻ 0.0005). TheLOS among patients who were treated with fusion wasapproximately 7.6 days compared with 5.4 days for thosewho did not undergo fusion (p Ͻ 0.0005). In 1986 to 1988dollars, the cost of hospitalization was $6491 for fusion-treated patients compared with $3793 for patients treatedsurgically without fusion (p = 0.0005). Logistic-regres-sion models were used to examine the risk of complica-tions or prolonged hospitalization and indicated that theRR for a complication or prolonged hospitalization withany type of lumbar fusion procedure was 2.7 (95% CI1.5–4.9). The lack of information regarding the indica-tions for surgery and the clinical outcome followingsurgery limit the usefulness of this information.Deyo, et al.,6examined lumbar surgery data for 1985obtained from the Health Care Financing Administrationfor all Medicare recipients, excluding those on Medicarefor chronic renal failure or Social Security Disability.Using ICD-9-CM diagnosis and procedure codes, datawere accrued on the frequency of lumbar surgery per-formed with or without fusion and the incidence of asso-ciated complications. The study was not undertaken pros-pectively nor was it certain that all patients were eligiblefor all therapies. Specific data were obtained for 6-weekmortality rates, requirements for assisted living, and theneed for blood transfusion. An economic analysis wascompleted for LOS and cost. These data were comparedwith similar data from 1 year prior to 4 years after thestudy date. A study population of 27,111 patients wasobtained of whom 1524 (5.6%) underwent lumbar fusion.For patients treated surgically with fusion, the mean hos-pital costs (1985 US dollars) were $10,091 compared with$6754 for patients treated without fusion (chi-square test,p Ͻ 0.0005). A logistic regression was completed to deter-mine RR and (95%) CIs for several variables. In the fu-sion group, the RR was 1.9 (95% CI 1.6–2.2) for the pres-ence of complications, 5.8 for blood transfusion (5.2–6.6),2.0 for 6-week mortality (1.2–3.4), and 2.2 for dischargeto a nursing home (1.7–3.0). This cohort study revealedthat lumbar surgery with fusion was more expensive andD. K. Resnick, et al.648 J. Neurosurg: Spine / Volume 2 / June, 2005SpineJune2005 5/24/05 10:42 AM Page 648
  13. 13. J. Neurosurg: Spine / Volume 2 / June, 2005Economic Outcome649TABLE1Summaryofstudiesinvolvingassessmentofeconomicoutcomeafterlumbarspinalsurgery*Authors&YearClassDescriptionResultsConclusionsTunturi,etal.,1979III133patientsunderwentlumbosacralfusionw/118FUsThecost/benefitratioforlumbosacralfusionwas1:2.9Lumbosacralfusioninaselectedpopulationhasaincluding2deaths.Costswerecalculatedin1976w/thecostin1976USdollarsas$5569&benefitaspositivecost/benefitratio.USdollarsbasedonperiophospitalization&FUs.$16,075.BenefitwasdefinedasthetimeoverthemeanFU(4.8yrs)forwhichthepatientwasemployed&wascalculatedbasedonmeansalaryduringthisperiod.Deyo,etal.,1991IIIAllMedicarerecipientsundergoinglumbaropin1985.Forthefusiongroup,RRw/95%CIforcomplicationsAgreatereconomiccostoffusionintheMedicareDataprovidedfromHCFAonthesepatientsfromwas1.9(1.6–2.2),bloodtransfusion5.8(5.2–6.6),population.Lumbarfusionisassociatedw/great-1yrpreopto4yrspostop.27,111patientswerestud-6-wkmortality2.0(1.2–3.4),assistedliving2.2(1.7–ermorbidity,mortality,&useofhospitalresourcesiedofwhom5.6%(1524)receivedlumbarfusion.3.0)(pϽ0.05).Theseresultswereconsistentbtwninolderadults.Noclearcohortoflumbardegen-Hospitalizationsexaminedforcomplications,mortal-spinalstenosis&spondylolisthesisw/hospitalcostserativepopulationdefinedforcostcomparison.ityat6wks,needforbloodtransfusion,&require-of$10,091(fusion)vs$6754(w/o)in1985dollarsmentsforassistedliving.Economicanalysiswas&asignificantlyshorterLOS(pϽ0.05ineachcate-completeforLOS&costs.gory).Deyo,etal.,1992III18,122hospitalizationsforlumbarspineop(84%in-~15%ofpatientsunderwentarthrodesis.Thecomplica-Patientswhoundergofusioninabroadpopulationvolvedspinalstenosisordiscdisplacement)fromtionratewas17.4%w/fusion&7.6%w/o(pϽaremoreapttohavelongerLOSsw/greatercom-1986–1988.15,280surgeriesw/oarthrodesis&0.0005).TheLOSwas7.6daysw/fusion&5.4w/oplicationrates&utilizationofhealthcareresourc-2785includedarthrodesis.Hospitalizationsexamin-(pϽ0.0005).Thecostin1986–1988dollarswas$6491es.Noclearcohortoflumbarfusionpopulationedforcomplications.Economicanalysiswascom-w/fusion&$3793w/o(pϽ0.0005).Nodetailsweredefinedforcostcomparison.pleteforLOS&costs.givenformortality.Franklin,etal.,1994III388patientsinWorkers’CompensationsysteminEmploymentwas16,32,&49%over1,2,&3yrs.ItEmploymentasaneconomicindicatormaybeusedWashingtonstate(1986–1987)whounderwentfu-waslesslikelytooccurinthiscohortthanhistoricalasanoutcomemeasurebutothercontrolgroupssion.Patientsatisfactionstudiedalongw/economiccontrols(RR=0.66,0.88,&0.93)at1,2,&3yrs;shouldbeconsidered.recoverybypatient.Simplesatisfactionsurveyexam-23%requiredreop&instrumentationdoubledthisrisk.inedback/legpain,QOL,decisiontoundergoop,&employmentat2yrs.Katz,etal.,1997III272patientsw/degenerativelumbarstenosis.Surgery:Individualsurgeonwaspredictorforarthrodesis.Hospi-Hospitalcostsofarthrodesis/fixationarehighestw/decompression(194),decompressionw/arthrode-talcostswere$12,615(noarthrodesis),$18,495(arth-nocleardefinedbenefit.Arthrodesisalonesis(37),&decompressionw/arthrodesis/fixationrodesis),$25,914(arthrodesis/fixation)(pϽ0.0001).showedimprovedreliefoflumbagoat6&24(41).Outcomesassessedw/respecttowalkingca-Noreliabilitygivenforwalking,satisfaction,orhealthmosw/oreliability.Significantvariabilityintro-pacity,back/legpain,satisfaction,healthstatusstatus.ducedbysurgeonchoiceforarthrodesis.(SF-36),&hospitalcost.Malter,etal.,1998III6376patientshadopforlumbardegenerativediseaseComplicationrate:18%(arthrodesis)to7%(none)(pϽTheeconomiccostsoflumbararthrodesisintheset-(1041foropincludingarthrodesis,5335foropw/o0.001).Hospitalcostsgreaterw/fusion($7101&tingofstenosis,discdisplacement,spondylolis-arthrodesis).Economicanalysisofhospitalization.$4161in1988dollars)(pϽ0.001).Reopratesimilarthesis,&degenerationaregreater.Noclearcohortbtwngroups,RR1.1(95%CI0.9–1.3).oflumbardegenerativepatientsusedforcomparison.Kuntz,etal.,2000IIIAcost-effectivenessstudyoflaminectomy,laminec-TheQALYs&costswerecalculated&foundtobeLumbarlaminectomyw/noninstrumentedfusioncom-tomyw/noninstrumentedfusion,&laminectomy$56,500forlaminectomyw/noninstrumentedfusionparedfavorablyw/decompression.Notenoughw/instrumentedfusion.Outcomewasassessedatcomparedw/laminectomyalone.Instrumentedfusiondataexistedonoutcomew/fixationtopresentit6mos&longterm&basedonpriorreports.Peri-wassubstantiallyhigher($3,112,800).Improvedout-positivelyonaneconomicscale.opcomplications&costs&reoprateswereallcomew/instrumentation(90vs80%)reducedtherel-basedonpriorreports.ativecostoffixation.Moller&Hedlund,2000II111patientsw/spondylolisthesiswhounderwentfu-Thefusion&exercisegroupshadsimilarnumbersofpa-RTEappearstobeanindicatorofimprovement.Asion(77)orexercise(34).Patientswererandom-tientsondisabilityat2yrs(46vs45%);however,thesatisfactionsurveywasnotreliablystudiedbutizedtothesegroupsiftheyhadՆ1yrofpain/sci-overallreductionwasgreaterforfusion(pϽ0.0001)didappeartobearesponsiveindicatorforout-atica.Evaluationwascompletedat1&2yrsusingcomparedw/exercise(p=0.23).Thesatisfactionsur-come&satsfactionhadimprovedmoreaftertheDRI,asatisfactionsurvey(muchbetter,better,veyshowedgoodresponsestobesignificantlyhigherfusion.unchanged,worse;wouldyourepeatop?),&RTE.intheopgroup(pϽ0.01).ContinuedSpineJune2005 5/24/05 10:42 AM Page 649
  14. 14. associated with higher risk for complications than lumbarsurgery without fusion.Katz and colleagues10completed a prospective observa-tional study of 272 patients with radiographically and clin-ically documented lumbar stenosis. Patients were treated atfour centers by eight surgeons over a 4-year period. Sur-gical treatment included decompression (194 cases), de-compression with fusion (37 cases), or decompression withfusion and internal fixation (41 cases). Patients were fol-lowed for 24 months and assessed for walking capacity,back and leg pain, satisfaction, and health status based onthe Sickness Impact Profile. Internal reliability was calcu-lated for the walking, pain, and satisfaction scales. Hospitalcosts were analyzed for each group. The individual sur-geon, in this study, was the greatest predictor for the per-formance of a fusion, with an RR of more than 10 based onlogistic regression. At 6 and 24 months, decompressionand fusion without internal fixation resulted in better reliefof back pain (p Ͻ 0.004 at 6 months; p Ͻ 0.01 at 24months) compared with the other treatment groups. Withmultivariate analysis, a trend was evident but did not reachstatistical significance. The reoperation rates were similarin all three groups (p = 0.15). Mean hospital costs were$12,615 per patient for decompression without fusion,$18,495 per patient for decompression with fusion, and$25,914 per patient for decompression with fusion and in-ternal fixation (p Ͻ 0.0001). This study indicated that in-creased costs for lumbar fusion may be offset by significantfunctional gains in the patients who undergo fusion withoutinstrumentation. The medical evidence cited in this report isconsidered Class III because of the retrospective nature ofthe study and selection bias by the operating surgeons as towhich patients were treated with internal fixation.Return to EmploymentTwo studies described resumption of employmentamong patients with low-back pain and compared thosetreated with lumbar fusion with those treated nonopera-tively. Moller and Hedlund13examined 111 patients overa 5-year period who had chronic low-back pain or sciati-ca for a minimum of 1 year as a result of isthmic spondy-lolisthesis. Treatments included arthrodesis with internalfixation (37 cases), arthrodesis without internal fixation(40 cases), or exercise (34 cases). Evaluation was per-formed at 1 and 2 years by using a Disability Rating In-dex, a satisfaction survey, and return-to-work rates. In thefusion and exercise groups there were similar numbers ofpatients receiving disability payments at 2 years (46 and45%, respectively); however, the surgical group had agreater degree of improvement (75 and 46%, respective-ly; p Ͻ 0.0001) compared with the exercise group (61 and45%, respectively; p = 0.23). Fritzell, et al.,8reported astudy of 294 patients with lumbar degenerative diseaseinvolving chronic lumbago of at least 2 years’ durationdue to L4–5 and/or L5–S18 disc degeneration. Patientswere randomized to surgical or nonsurgical groups. Pa-tients in the surgical group underwent posterolateral fu-sion (73 cases), posterolateral fusion with internal fixation(74 cases), or interbody fusion with internal fixation (75cases). Seventy-two patients received medical manage-ment including physical therapy. Evaluation was accom-plished at 6, 12, and 24 months by using functional out-D. K. Resnick, et al.650 J. Neurosurg: Spine / Volume 2 / June, 2005TABLE1ContinuedAuthors&YearClassDescriptionResultsConclusionsSlosar,etal.,2000III141patientsunderwentcircumferentiallumbarinstru-133FUpatients(10.5%=1,51.1%=2,19.5%=3,&Satisfactionappearstobearesponsiveoutcomemea-mentedfusion,eitherprimary(31%)orsecondary18.8%=4).RTEoccurredin38%ofpatients;itwassureat37mos;however,itsreproducibilitywas(69%).FUaveraged37mos&wasdonebyabasicmorelikelyinthosenotinvolvedw/Workers’Com-nottested.RTEisaresponsivemeasure&im-satisfactionsurvey:1)opmetexpectations;2)oppensation(57vs22%;pϽ0.001).Therewasa20%provesinthenoncompensationpatients.Acom-improvedmycondition;3)opimprovedbutwouldcomplicationrateincludedtransientweakness,infec-plicationrateof20%wasseen,suggestinganega-notredo;4)opworsenedcondition.tion,&graftextrusion.tiveeconomicimpact.Fritzell,etal.,2001II294patientsw/L4–S1discdegeneration&LBPwhow/overallassessment,63%intheopgroupindicatedSatisfactionsurveysseemtoberesponsiveovertheunderwentop(222)orexpectant(72)managementtheywerebetterormuchbettercomparedw/29%sametimeinterval,&RTEindicatesresponsive-overa6-yrperiod.Evaluationwascompletedat6,inthenonopgroup(pϽ0.0001).ThenetRTEratenessat24mos.12,&24mosusingtheODI,Million,&generalwashigherintheopgroup(36%)thanthenonopfunctionscorealongw/patientassessment.RTEgroup(13%,pϽ0.002).wasalsomonitored.Christensen,etal.,2002III148patientsunderwentlumbarfusionw/73inPLFRTEwassimilarinbothgroupsbutimprovedfrom24%RTEdidnotappeartoworkasaresponsiveindica-groupand75inALIF/PLFgroup.Threepatientsto36%(nostatisticsusedtoanalyze)w/nodifferencetorofimprovement,&RTEseemedtocorrelatewerelosttoFU.RTEwasalsofollowedat2years.btwnsubgroups.w/animprovementinDPQscore.NocontrolsFUperformedat0,1,&2yrs.wereused.Christensen,etal.,2002II129patientsw/chronicLBP&isthmicspondylolis-Theinstrumentedgrouphada28%reopratecomparedMedicaloutcomebyreop&optimemaybeares-thesis,primarydegeneration,orsecondarydegener-w/14%forthenoninstrumentedgroup(pϽ0.03).Opponsiveindicatorw/in5yrsoflumbarfusionsw/ationwhounderwentinstrumentedornoninstru-time212vs127min(pϽ0.0001)w/greaterperiopinstrumentation.mentedfusion.Outcomeat5yrswasdoneusingbloodloss(pϽ0.01).functionalquestionnairesalongwithratesofRTE&reop.*ALIF=anteriorlumbarinterbodyfusion;DPQ=DallasPainQuestionnaire;FU=followup;HCFA=HealthCareFinancingAdministration;LBP=low-backpain;ODI=OswestryDisabilityIndex;PLF=posterolateralfusion;QALY=quality-adjustedlifeyear;QOL=qualityoflife;RTE=returntoemployment;SF-36=ShortForm–36.SpineJune2005 5/24/05 10:42 AM Page 650
  15. 15. come questionnaires and return-to-work status. In an over-all assessment, 63% in the surgical group indicated theywere better or much better following treatment comparedwith 29% in the nonsurgical group (p Ͻ 0.0001). The netreturn-to-work rate was 39% in the surgical group andonly 23% in the nonsurgical group (p Ͻ 0.05). These twostudies suggest that the resumption of employment is aresponsive economic outcome measure for patients withlow-back pain who may be considered surgical candi-dates.In the study by Franklin and colleagues7of Workers’Compensation patients, the end of total disability wasmonitored in patients who underwent lumbar fusion be-tween 1986 and 1987. The termination of total disability asan end point occurred in 16% of treated patients at 1 year,32% at 2 years, and 49% at 3 years; however, comparedwith historical controls for Workers’ Compensation pa-tients, the RR of ending total disability was less likelyamong patients treated with lumbar fusion (0.66 at 1 year,0.88 at 2 years, and 0.93 at 3 years) compared with Work-ers’ Compensation patients as a whole. In contrast, Chris-tensen, et al.,1examined 148 patients who underwent lum-bar fusion over a 3-year period: posterolateral fusion (73cases) or a combination of posterolateral and anterior inter-body fusion procedures (75 cases). Outcome was assessedover 2 years. Overall improvement was greatest in the cir-cumferential treatment group, with a lower reoperation rate(22% compared with 7%, p Ͻ 0.009). The return-to-workrate improved in both groups from 24 to 36% with no dif-ference between subgroups. No statistical analyses wereused to assess the overall return-to-work rate. Slosar, etal.,14reported on 133 patients who underwent circumferen-tial fusion during a 2-year follow-up period. In this group,50 patients (38%) returned to work; 16 (22%) of the 73injured workers resumed work compared with 34 (57%) ofthe 60 patients who were not receiving Workers’ Com-pensation (chi-square test, p Ͻ 0.001). These studies indi-cated that return to work and/or termination of disabilitypayment are responsive measures for economic outcomeafter lumbar fusion procedures. They further indicate thatthe presence of a compensable injury is associated with alower rate of return to work.Cost–Benefit AnalysisKuntz and colleagues11undertook a cost-effectivenessanalysis of lumbar fusion by constructing a hypotheticalmodel based on historical reports in prior clinical studies.They examined lumbar laminectomy, laminectomy withnoninstrumented fusion, and laminectomy with instru-mented fusion. Rates of clinical improvement and returnto employment were culled from series reported in the lit-erature as were costs, complication rates, fusion rates, re-operation rates, and the incidence of clinical worsening.Each negative and positive outcome was assigned a rela-tive value pertaining to quality of life, which the authorsadjusted according to hypothetical outcomes.The authors determined that laminectomy with non-instrumented fusion cost $56,500 per quality-adjustedyear of life compared with laminectomy alone.11The addi-tion of instrumentation to lumbar fusion procedure cost$3,112,800 per quality-adjusted year of life. The authorsconcluded that laminectomy with noninstrumented fusioncompared favorably with decompression alone; however,improvement in outcome associated with instrumentationwas not well defined enough to accrue a benefit. Theauthors noted that a hypothetical rate of 90% symptomrelief for patients treated with instrumented fusion com-pared with 80% for noninstrumented patients would re-duce the quality-adjusted year of life cost to $82,400.Tunturi and colleagues15analyzed 133 consecutive pa-tients who underwent lumbosacral fusion between 1968and 1975. Results were reported for 116 patients in whomthe mean follow-up period was 4.8 years. These authorscalculated the mean expense of the hospital stay and post-operative visits in 1976 dollars. Economic benefits werecalculated based on return-to-employment rates comparedwith the costs of continued disability. The rate of return toemployment was approximately 31%. The mean cost in1976 US dollars for a lumbosacral fusion was $5569. Themean economic benefit in 1976 US dollars for the sameperiod was $16,075. The calculated cost/benefit ratio wastherefore 1:2.9 for lumbosacral arthrodesis. The authorsconcluded that lumbosacral fusion had a positive cost–be-nefit ratio when return-to-employment status and the ter-mination of disability payment were considered as indicesof economic outcome.SummaryLumbar fusion may be associated with a high short-term cost, especially if instrumentation is placed; how-ever, there appear to be long-term economic benefits as-sociated with lumbar fusion including resumption ofemployment. To describe the economic impact of lumbarfusion for degenerative disease adequately, it is importantto define the patient population treated with fusion and tocompare efficacy as well as the costs of other treatmentalternatives. Any such analysis should include both short-and long-term costs and benefits.Key Issues for Future InvestigationThe application of valid and reliable outcome measuresin conjunction with a complete short- and long-term eco-nomic analysis will be necessary to assess fully theeconomic impact of lumbar fusion. To reach meaningfulconclusions, it is imperative to compare the economic out-comes of patients treated with lumbar fusion with those inpatients with similar disease treated without fusion and toinclude all relevant costs. This analysis should include sub-sequent operative and nonoperative medical care, ongoingdisability costs, and the costs of loss of productivity. Mea-sures such as return-to-work status and quality-adjusted lifeyears must be included in to allow the development ofmeaningful data.References1. Christensen FB, Hansen ES, Eiskjaer SP, et al: Circumferentiallumbar spinal fusion with Brantigan cage versus posterolateralfusion with titanium Cotrel-Dubousset instrumentation: a pros-pective, randomized clinical study of 146 patients. Spine 27:2674–2683, 20022. Christensen FB, Hansen ES, Laursen M, et al: Long-term func-tional outcome of pedicle screw instrumentation as a supportJ. Neurosurg: Spine / Volume 2 / June, 2005Economic Outcome651SpineJune2005 5/24/05 10:42 AM Page 651
  16. 16. for posterolateral spinal fusion: randomized clinical study witha 5-year follow-up. Spine 27:1269–1277, 20023. Davis H: Increasing rates of cervical and lumbar spine surgeryin the United States, 1979–1990. Spine 19:1117–1124, 19944. Deyo RA, Cherkin D, Conrad D, et al: Cost, controversy, crisis:low back pain and the health of the public. Annu Rev PublicHealth 12:141–156, 19915. Deyo RA, Cherkin D, Loeser JD, et al: Morbidity and mortali-ty in association with operations on the lumbar spine. The influ-ence of age, diagnosis, and procedure. J Bone Joint Surg Am74:536–543, 19926. Deyo RA, Ciol MA, Cherkin DC, et al: Lumbar spinal fusion.A cohort study of complications, reoperations, and resource usein the Medicare population. Spine 18:1463–1470, 19937. Franklin GM, Haug J, Heyer NJ, et al: Outcome of lumbarfusion in Washington State workers’ compensation. Spine 19:1897–1904, 19948. Fritzell P, Hagg O, Wessberg P, et al: 2001 Volvo AwardWinner in Clinical Studies: Lumbar fusion versus nonsurgicaltreatment for chronic low back pain: a multicenter randomizedcontrolled trial from the Swedish Lumbar Spine Study Group.Spine 26:2521–2534, 20019. Katz JN: Lumbar spinal fusion. Surgical rates, costs, and com-plications. Spine 20 (24 Suppl):S78–S83, 199510. Katz JN, Lipson SJ, Lew RA, et al: Lumbar laminectomy aloneor with instrumented or noninstrumented arthrodesis in degen-erative lumbar spinal stenosis. Patient selection, costs, and sur-gical outcomes. Spine 22:1123–1131, 199711. Kuntz KM, Snider RK, Weinstein JN, et al: Cost-effectivenessof fusion with and without instrumentation for patients with de-generative spondylolisthesis and spinal stenosis. Spine 25:1132–1139, 200012. Malter AD, McNeney B, Loeser JD, et al: 5-year reoperationrates after different types of lumbar spine surgery. Spine 23:814–820, 199813. Moller H, Hedlund R: Surgery versus conservative manage-ment in adult isthmic spondylolisthesis—a prospective, ran-domized study: part 1. Spine 25:1711–1715, 200014. Slosar PJ, Reynolds JB, Schofferman J, et al: Patient satisfac-tion after circumferential lumbar fusion. Spine 25:722–726,200015. Tunturi T, Niemela P, Laurinkari J, et al: Cost-benefit analysisof posterior fusion of the lumbosacral spine. Acta OrthopScand 50:427–432, 1979Manuscript received December 7, 2004.Accepted in final form March 22, 2005.Address reprint requests to: Daniel K. Resnick, M.D., Depart-ment of Neurological Surgery, University of Wisconsin MedicalSchool, K4/834 Clinical Science Center, 600 Highland Avenue,Madison, Wisconsin 53792. email: Resnick@neurosurg.wisc.edu.D. K. Resnick, et al.652 J. Neurosurg: Spine / Volume 2 / June, 2005SpineJune2005 5/24/05 10:42 AM Page 652
  17. 17. RecommendationsStandards. Static lumbar radiographs are not recom-mended as a stand-alone means to assess fusion status fol-lowing lumbar arthrodesis surgery.Guidelines. 1) Lateral flexion and extension radiogra-phy is recommended as an adjunct to determine the pres-ence of lumbar fusion postoperatively. The lack of motionbetween vertebrae, in the absence of rigid instrumenta-tion, is highly suggestive of successful fusion. 2) Tech-netium-99 bone scanning is not recommended as a meansto assess lumbar fusion.Options. Several radiographic techniques, including sta-tic radiography, lateral flexion–extension radiography, and/or CT scanning, often in combination, are recommendedas assessment modality options for the noninvasive evalu-ation of symptomatic patients in whom failed lumbar fu-sion is suspected.RationaleLumbar fusion is performed in patients with pain due tolumbar degenerative disease. An outcome measure fre-quently cited in studies evaluating lumbar fusion tech-niques is the “radiographic fusion rate;” however, radio-graphic fusion is not consistently defined throughout theliterature. The purpose of this review is to examine the lit-erature regarding the ability of various diagnostic tech-niques to assess fusion status after lumbar fusion is per-formed to treat degenerative disease.Search CriteriaA computerized search of the database of the NationalLibrary of Medicine between 1966 and July 2003 was con-ducted using the search terms “lumbar spine fusion assess-ment,” “lumbar spine pseudoarthrosis,” or “lumbar spinefusion outcome.” The search was restricted to references inthe English language involving humans. This yielded a to-tal of 1076 references. The titles and abstracts of each ofthese references were reviewed. Only papers concernedwith the assessment of fusion status following arthrodesisprocedures for degenerative lumbar disease were included.Additional articles were obtained from the bibliographiesof the selected articles. Forty-five references were identi-fied that provided either direct or supporting evidence rele-vant to the radiographic assessment of lumbar fusion status.Reports involving Class III or better medical evidence arelisted in Table 1. Supportive data are provided by addition-al references listed in the bibliography.Scientific FoundationOpen surgical exploration is the only method that al-lows direct inspection of fusion integrity. This procedureJ. Neurosurg: Spine / Volume 2 / June, 2005J Neurosurg: Spine 2:653–657, 2005Guidelines for the performance of fusion proceduresfor degenerative disease of the lumbar spine.Part 4: radiographic assessment of fusionDANIEL K. RESNICK, M.D., TANVIR F. CHOUDHRI, M.D., ANDREW T. DAILEY, M.D.,MICHAEL W. GROFF, M.D., LARRY KHOO, M.D., PAUL G. MATZ, M.D.,PRAVEEN MUMMANENI, M.D., WILLIAM C. WATTERS III, M.D., JEFFREY WANG, M.D.,BEVERLY C. WALTERS, M.D., M.P.H., AND MARK N. HADLEY, M.D.Department of Neurosurgery, University of Wisconsin, Madison, Wisconsin; Department ofNeurosurgery, Mount Sinai Medical School, New York, New York; Department of Neurosurgery,University of Washington, Seattle, Washington; Department of Neurosurgery, Indiana University,Indianapolis, Indiana; Departments of Orthopedic Surgery and Neurosurgery, University ofCalifornia at Los Angeles, California; Department of Neurosurgery, University of Alabama atBirmingham, Alabama; Department of Neurosurgery, Emory University, Atlanta, Georgia;Bone and Joint Clinic of Houston, Texas; and Department of Neurosurgery, Brown University,Providence, Rhode IslandKEY WORDS • lumbar spine • fusion • radiography • treatment outcome •practice guidelines653Abbreviations used in this paper: CT = computerized tomogra-phy; NPV = negative predictive value; PPV = positive predictivevalue; RSA = roentgen stereophotogrammetric analysis.SpineJune2005 5/24/05 10:42 AM Page 653

×