The document discusses the Appropriateness Criteria for evaluating back pain, noting that acute low back pain is a leading cause of disability. While most cases are self-limiting, imaging may be warranted to identify red flags like trauma, weight loss, or neurological deficits. Common imaging modalities for back pain are listed along with their strengths and limitations. Plain films are inexpensive but MRI provides the best soft tissue contrast. Imaging correlates best with outcomes when combined with clinical examination, and is usually not needed for uncomplicated back pain without red flags.

1. Appropriateness Criteria in the evaluation of back pain Edgar Colón Negrón, MD Angel GómezCintrón, MD, MPH Diagnostic Radiology UPR-RCM

2. www.acr.org

5. UNIVERSITY OF PUERTO RICO · SCHOOL OF MEDICINE ·DIAGNOSTIC RADIOLOGY

11. Introduction Acute low back pain is the leading cause of disability for persons younger than 45 in the US High prevalence and high cost in dealing with this problem After multiple studies it is clear that uncomplicated LBP is a benign self-limited condition that does not warrant any imaging studies Vast majority of patients are back to their usual activities in 30 days The challenge for the clinician is to distinguish who should be evaluated to exclude a more serious problem

12. Indicationsforradiographicevaluationofthespine Red Flags: Significant trauma, ormilderifage >50 Unexplainedweightloss Unexplainedfever Immunosuppression HistoryofCancer IV Drug use Osteoporosis, prolonged use ofsteroids Age > 70 Focal neurologicdeficitordisablingsymptoms Durationlongerthan 6 weeks

13. Imaging Modalities Plain films Bone scintigraphy CT MRI Myelography

14. Plain films Inexpensive Available Screening ( trauma ) Assessment of subluxation and alignment

15. Normal AP, Lat, Obl and Swimmer’s view of cervical spine Look for alignment, vertebral body shape, posterior elements and prever tebral soft tissues. Examination must include C7. Oblique views for evaluation of uncovertebral joints, neural foramina stenosis and facet alignment

16. Legend: 1, v. body 2, transverse process 3, posterior arch atlas 4, 5 facet joints 6, lamina 7, spinous process 8, uncinate process 10, disc space 11, articular facet joint 12, left neural foramina 14, pars interarticularis 15, pedicle

18. Indicationsforradiographicevaluationofthespine Red Flags: Significant trauma, ormilderifage >50 Unexplainedweightloss Unexplainedfever Immunosuppression HistoryofCancer IV Drug use Osteoporosis, prolonged use ofsteroids Age > 70 Focal neurologicdeficitordisablingsymptoms Durationlongerthan 6 weeks

20. IsotopeBone Scan Moderatelysensitiveforthepresenceoftumors, infectionoroccult fractures; notspecific Bonescintigraphywith SPECT followedwith CT is more sensitive in the diagnosis ofspondylolysisthan MR SPECT may localizethesourceofpain in patientswith articular facet OA

22. CT of the spine Superior bone detail, not as useful as MR in depicting disc protrusions CT is useful in depicting spondylolysis Poor visualization of the cord, intrathecal contrast needed. Great technique for the assessment of pseudoarthosis, scoliosis, post surgical evaluation of bone graft integrity, surgical fusion and instrumentation

31. MRI Examination of choice in complicated LBP Multidisciplinary agreement on terminology facilitates reporting of MR findings No radiation Excellent contrast resolution Multiplanarcapabilities Great visualization of the spinal cord Higher soft tissue contrast than CT

32. MR in low back pain Acute back painwith radiculopathy suggeststhepresenceofdemonstrablenerverootcompressionon MR MR findingsofModicendplatechanges, anterolisthesis or disk extrusion are more stronglyassociatedwithlow back painthan disk changeswithoutendplatechanges Particularlyefficacious in thedetectionof red flags diagnosis Post operativepatientsenhanced MR allowsdistinctionbetweendiscandscartissue

33. T1 (left) and T2 (right) weighted images of a normal dorsal spine

34. T2 weighted images of the lumbar spine. Extreme parasagital views demonstrating root foraminas dorsal root ganglion

35. T2 T1 Normal Lumbar Spine

36. CT vs MRI

37. Imaging in the diagnosis of spinal diseases

38. Degenerative diseases and back pain; epidemiologic facts Affects 5% of the adult population per year with a lifetime incidence of 70%-80% 90% of patients recover within 3 months 286,000 surgeries per year The estimated cost of this entity to the society is between 16 – 60B, with 10B in direct medical care alone 2B in MRI alone Modic MT, MRI Clinics of North Amer, Aug 1999

39. Spinal Degeneration Normal consequence of the aging process, that can be predisposed or accelerated by developmental and acquired factors Two major degenerations; Osteochondral which affects the intervertebral disc ( synchondral articulation) Osteoarthritic affecting the synovial joints (uncovertebral joints in the cervical spine and the facet joints)

40. Sagital fluid sensitive Pulse sequences Multisegmental degenerative osteochondral changes Normal sagital fluid sensitive Pulse sequence

42. T2 T1 annular fissure

43. Spinal canal stenosis

45. Degenerative osteoarthritic changes to the right uncovertebral joint of the cervical spine with nerve root foramina narrowing

46. Annular displacement

47. Displacement of the nucleus pulposus (disc herniations) Due to degeneration of the annular fibers Displacement can be superior, inferior or most commonly posterior Definition Protrusion: within the annulus, annular fissure Extrusion: beyond the annulus but contained by the PLL Sequestrum = free fragment

48. A-C normal variants, D protruded , E extruded, F and G free fragments

49. Degenerative osteochondral changes in the with resultant end plate herniations (Schmorl’s nodes)

50. Protruded disc

51. T1 T2 small annular fissures

52. Central extruded disc limited by the posterior Longitudinal ligament

53. Free fragment

54. Correlation of symptoms The three most important for localization and causal differential are: Pain Sensory changes Weakness

55. Patients more likely to have a favorable outcome from surgery should have; - A clear history of sciatica - Straight leg raising of less than 30 - Objective neurologic signs - Imaging evidence of a disc herniation that corresponds with the anatomical area of concern

57. Degenerative segmental instability

58. Bulging discs

60. Axial T1WI pre and post gadolinium injection demonstrating scar at surgical site Contrast enhancement is needed for all post op patients.

61. RelativeRadiationLevel “Thereispotentialforadversehealtheffectsassociatedwithradiationexposure, thereforeitisanimportant factor toconsiderwhenorderingimagingstudies.” RRL isusedtoestimatepopulation total radiationriskassociatedwithanimagingprocedure.

62. The bottom line Imaging correlates with outcome only when combined with clinical data Most patients with low back pain will go into clinical response and may not need imaging procedures unless a red flag is raised Knowing of the red flags is important in order to perform the most appropriate imaging procedure, when needed Back pain will continue to be an important clinical topic in the near future due to its economic implications.

63. RemembertheRED FLAGS Significant trauma, ormilderifage >50 Unexplainedweightloss Unexplainedfever Immunosuppression HistoryofCancer IV Drug use Osteoporosis, prolonged use ofsteroids Age > 70 Focal neruologicdeficitordisablingsymptoms Durationlongerthan 6 weeks

64. Reference ACR AppropriatenessCriteria © acr.org