CURRENT ISSUES                                                   Congenital Scoliosis                                     ...
J Pediatr Orthop   & Volume 27, Number 1, January/February 2007                          Congenital Scoliosis: A Review an...
Hedequist and Emans                                            J Pediatr Orthop   & Volume 27, Number 1, January/February ...
J Pediatr Orthop   & Volume 27, Number 1, January/February 2007                          Congenital Scoliosis: A Review an...
Hedequist and Emans                                            J Pediatr Orthop   & Volume 27, Number 1, January/February ...
J Pediatr Orthop   & Volume 27, Number 1, January/February 2007                          Congenital Scoliosis: A Review an...
Hedequist and Emans                                           J Pediatr Orthop   & Volume 27, Number 1, January/February 2...
J Pediatr Orthop   & Volume 27, Number 1, January/February 2007                          Congenital Scoliosis: A Review an...
Hedequist and Emans                                             J Pediatr Orthop   & Volume 27, Number 1, January/February...
J Pediatr Orthop       & Volume 27, Number 1, January/February 2007                                          Congenital Sc...
Hedequist and Emans                                                               J Pediatr Orthop    & Volume 27, Number ...
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Cong scoliosis

  1. 1. CURRENT ISSUES Congenital Scoliosis A Review and Update Daniel Hedequist, MD and John Emans, MD concert with congenital scoliosis are at risk of severeAbstract: Vertebral anomalies causing congenital scoliosis are restrictive lung disease and of thoracic insufficiency.13classified on the basis of failures of formation, segmentation, or both. Expansion thoracoplasty and placement of vertical expansionThe natural history depends on the type of anomaly and the location prosthetic titanium rib (VEPTR) devices have evolved into aof anomaly. Patient evaluation focuses on the history and physical treatment option for children with the most difficult problems.examination, followed by appropriate imaging modalities. The The purpose of this article is to serve as a review and updatehallmark of surgical treatment is early intervention before the of congenital scoliosis.development of large curvatures. The surgical treatment of acongenital deformity mandates the use of neurological monitoring tominimize the risk of perioperative neurological deficit. Modern CLASSIFICATIONsurgical techniques have evolved to include the routine use of spinal Vertebral anomalies causing congenital scoliosis mayinstrumentation. Patients with associated chest wall deformities or be caused by a failure of formation, by failure of segmenta-large compensatory curves may be candidates for vertical expansion tion, or by a combination of these 2 factors, resulting in aprosthetic titanium rib placement or growing rods insertion to mixed deformity.14 An incomplete failure of formation leadsmaximize growth. to a wedge vertebra (Fig. 1). A wedge vertebra has asymmetry in height, with 1 side being hypoplastic; however, there areKey Words: congenital scoliosis, surgical treatment, VEPTR bilateral pedicles. Complete failure of formation results in a(J Pediatr Orthop 2007;27:106Y116) hemivertebra, with the absence of 1 pedicle and a region of vertebral body. Hemivertebra may be further classified on the basis of the presence or the absence of fusion to the vertebral bodies above and/or below.15 An unsegmented hemivertebraT he prevalence rate of congenital scoliosis is thought to be approximately 1 in 1000 live births.1,2 There is currentlyno known cause for the development of a congenital vertebral is fused to the vertebral body above and below; a partially segmented hemivertebra is fused to the vertebral body either above or below; and a fully segmented hemivertebra isanomaly. Strong evidence based on basic science research in separated from the body above and below by disk space.mice suggests that maternal exposure to toxins, such as Hemivertebra may occur at ipsilateral adjacent levels of thecarbon monoxide exposure, may cause congenital scolio- spine, which produces significantly asymmetrical spinesis.3,4 Associations with maternal diabetes and ingestion of growth, or a hemivertebra may be counterbalanced by aantiepileptic drugs during pregnancy have also been postu- hemivertebra on the contralateral side of the spine in the samelated as possible causes.5,6 Genetic inheritance has been region, separated by 1 or several healthy vertebrae (this isshown responsible for some congenital vertebral anomalies; termed a hemimetameric shift).16however, there is no clear-cut genetic etiology of congenital The defects of segmentation are characterized byscoliosis to date.2,7,8 Although fetal imaging modalities, such abnormal bony connections between vertebrae (Fig. 2).as magnetic resonance imaging (MRI) and ultrasound, have These bony connections may be bilateral and symmetrical,improved our ability to diagnose vertebral anomalies in utero, resulting in a block vertebra. Segmentation defects caused bythey do not have any therapeutic role in the clinical unilateral bony fusions are termed bars and may act as asetting.9,10 The goal of treatment of congenital scoliosis is unilateral growth tether. Occasionally, a segmentation defectearly diagnosis and treatment, if indicated. Modern imaging may span an ipsilateral formation defect, resulting in amodalities have improved our diagnostic capabilities and our unilateral bar and a contralateral hemivertebra.17ability to screen for spinal dysraphism.11,12 Surgical treat- Mixed deformities are common and may be difficult toment revolves around early arthrodesis for progressive define, given the abnormal anatomy and the resultant occa-deformities and has evolved to include the routine use of sionally severe deformity.18 Scoliosis caused by multiplespinal instrumentation. Patients with congenital rib fusions in vertebral anomalies may also be associated with rib abnorm- alities; this may be associated with severe stunting of thoracic volume and a restriction of pulmonary function.13,19From the Childrens Hospital Boston, Harvard Medical School, Boston, MA.The authors state that they no proprietary interest in the products named in this article. NATURAL HISTORYReprints: Daniel Hedequist, MD, Childrens Hospital Boston, 300 Longwood Ave, Department of Orthopedics, Hunnewell 2, Boston, MA 02114. E-mail: The progression of congenital scoliosis depends on both the type and the location of the vertebral anomaly.18 CurveCopyright * 2007 by Lippincott Williams & Wilkins progression is caused by unbalanced growth of 1 side of the106 J Pediatr Orthop & Volume 27, Number 1, January/February 2007 Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
  2. 2. J Pediatr Orthop & Volume 27, Number 1, January/February 2007 Congenital Scoliosis: A Review and UpdateFIGURE 1. Schematic representation of formation failures. A,Wedge vertebra. B, Fully segmented hemivertebra. C, Partiallysegmented hemivertebra. D, Unsegmented hemivertebra.Reproduced with permission from Hedequist and Emans.14spine relative to the other. Radiographically, definable diskssignify the presence of vertebral growth plates and, whenasymmetrical or more present on 1 side of the spine than onthe other, have potential for asymmetrical growth in that areaof the spine. Thus, fully segmented hemivertebra withhealthy, definable disks above and below have much morepotential to cause curvature compared with an unsegmentedhemivertebra, which is fused to the vertebra above andbelow.15 Likewise, the asymmetrical tethering of the spineleads to curvature with growth, as is seen with bars or rib FIGURE 3. Radiograph, taken from an adolescent patient,fusions on the concavity of a curve. of an untreated lumbar hemivertebra causing progressive The rate of curve progression depends on the type of deformity.anomaly, the age of the patient, and the location of the curve(Fig. 3). Curve progression occurs more rapidly during the than those seen at other areas of the spine. The anomaly mostfirst 5 years of life and, again, during the adolescent growth probable to produce the most severe scoliosis is the unilateralperiod of puberty; these 2 periods represent the most rapid bar with contralateral hemivertebra, followed by a unilateralstages of spine growth.20 Anomalies at the cervicothoracic bar, a hemivertebra, a wedge vertebra, and, finally, the mostand lumbosacral junctions produce more visible deformities benign of all anomaliesVthe block vertebra.18 Mixed deformities are unpredictable, and their severity depends on the amount of unbalanced growth potential. PATIENT EVALUATION The evaluation of a patient with congenital scoliosis focuses on the physical examination, the search for other anomalies, and radiographic evaluation. The physical exam- ination should start with the height and the weight of the patient, given that growth plays a significant role in curve progression. The skin needs to be evaluated for any evidence of spinal dysraphism, such as abnormal pigmentation, hairy patches, or skin tags over the cutaneous region of the spine. Spinal dysraphism may also manifest itself in the lower extremities, and signs would include asymmetrical calves, cavus feet, clubfeet, vertical tali, and abnormal neurological findings. The spinal examination itself focuses on any evidence of truncal or pelvic imbalance. Rib cage deformities and anomalies need to be evaluated, as does the inspiratoryFIGURE 2. Schematic representations of failures of and expiratory capacity of the chest wall, given the possibilitysegmentation. A, Block vertebra. B, Bar. C, Bar with of any associated restrictive lung disease. Spinal balance incontralateral hemivertebra. Reproduced with permission both the coronal and the sagittal planes needs to be evaluated.from Hedequist and Emans.14 Truncal imbalance, head tilt, shoulder inequality, and pelvic* 2007 Lippincott Williams & Wilkins 107 Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
  3. 3. Hedequist and Emans J Pediatr Orthop & Volume 27, Number 1, January/February 2007balance all need to be addressed and recorded. Given theassociation of neural axis abnormalities and the possibility ofneurological compromise in congenital spine deformities, athorough neurological examination of strength, sensation, andreflexes, including abdominal reflexes, becomes mandatory. ASSOCIATED ANOMALIES Neural axis abnormalities are present in up to 35% ofpatients, as detected with MRI.21 These abnormalities include(but are not limited to) diastematomyelia (split cord), cordtethering, Chiari malformations, and intradural lipomas. Theabsence of cutaneous signs of dysraphism and the absence ofneurological deficit do not rule out an intraspinal dysraphism. Congenital heart disease is observed in up to 25% ofpatients with congenital scoliosis.22 The abnormalities maybe benign and may be detected during a routine preoperativeappointment; however, they may be severe, and the child mayhave an already extensive cardiac history. The cardiac defectsrange from atrial and ventricular septal defects, which are themost common abnormalities, to complex congenital heartdefects, such as tetralogy of Fallot and transposition of thegreat vessels. Patients who are undergoing an operation for acongenital spine deformity need a screening echocardiogram, FIGURE 4. Three-dimensional CT scan showing the anatomicalwith referral to a cardiologist if indicated. detail of a lumbar partially segmented hemivertebra. Genitourinary anomalies are observed in up to 20% of radiation that children receive during CT examination, andpatients with congenital scoliosis.22 The abnormalities may surgeons should urge that these protocols be used. The abilitybe asymptomatic and may be detected on a routine screening to create 3-dimensional images is software based and does nottest, or they may be significant enough to have already been require additional radiation exposure. Hedequist anddiagnosed and have required treatment. Anomalies may Emans,11 in a retrospective study comparing the findings ataffect the kidneys, ureters, bladder, or urethra. These include operation compared with the findings seen on preoperativehorseshoe kidney, renal aplasia, duplicate ureters, and radiographs and CT scans, concluded that CT scans werehypospadias. A renal ultrasound remains to be the criterion 100% accurate in defining the anatomy and the unrecognizedstandard for urological screening in these patients, and an anomalies not seen on plain films. Newton et al27 found thatabnormal ultrasound result demands a referral to a urologist. in 17 of 31 patients with congenital spine deformities, CT Musculoskeletal anomalies occur frequently in associa- scanning with image reformatting allowed for the identifica-tion with congenital spine anomalies. Disorders, such as tion of unrecognized malformations not seen on plain filmsclubfeet, Sprengel deformity, Klippel-Feil deformity, devel- alone. Preoperative CT scans help in clearly defining theopmental dysplasia of the hip, and upper and lower limb anatomy and avoid any unexpected encounters with posteriordeformities, need to be evaluated and treated appropriately if element deficiencies at the time of surgical intervention.present in these patients. Computed tomography scans that include the chest and ribs are useful for the evaluation of chest wall deformity and IMAGING lung volume in congenital deformities with chest wall anoma- Plain radiographs remain a reliable standard for lies, chest deformity, or thoracic insufficiency. Smith et al61diagnosis of congenital anomalies and for following curve were able to use 3-dimensional CT data to define lung volumesprogression.23 The details of vertebral anomalies may be in patients who were too young for pulmonary function tests;particularly evident on plain x-ray results of the infant. The subsequently, they were able to use this data as a measure ofadvent of computed tomography (CT) and MRI have improvement in lung function after expansion thoracoplasty.improved our ability to study spinal anatomy and to screen Others have used this tool to measure improvements in chestfor spinal dysraphism.11,21,24 wall, lung volume, and spinal growth measurements after We routinely use CT with 3-dimensional reconstruc- expansion thoracoplasty.29,30tions for preoperative assessment and evaluation of complex Magnetic resonance imaging has replaced myelogramdeformities, but not for routine observation or serial as the procedure of choice in detecting occult spinaldocumentation11 (Fig. 4). Concern exists regarding the dysraphism. The efficacy of MRI has been widely studiedsignificant radiation exposure during CT examination.25,26 and documented in patients with congenital scoliosis.12,21Tube current (in milliamperes), kilovoltage, and, particularly, The prevalence rate of spinal dysraphism detected using MRIslice thickness all contribute to the amount of radiation that a approaches 30% in patients with congenital spine deformi-patient receives in the CT scanner.11,25 Most probably, ties. We do not routinely instruct to perform an MRI on allinstitutions do have written protocols in place to minimize the patients with congenital spine deformities; however, patients108 * 2007 Lippincott Williams & Wilkins Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
  4. 4. J Pediatr Orthop & Volume 27, Number 1, January/February 2007 Congenital Scoliosis: A Review and Update the same time as the deformity surgery; however, this depends on the magnitude of each procedure and the opinion of the neurosurgeon.32 Early and aggressive treatment of deformities before they become severe helps in minimizing the risk to the patient. The avoidance of lengthening the spinal cord intraoperatively by avoiding intraoperative distraction and by using shortening procedures during surgery also mini- mizes the chance of a perioperative neurological deficit. The use of controlled hypotension to minimize blood loss should be monitored carefully to minimize the occurrence of unwanted cord ischemia, especially during any corrective maneuvers. Motor- and sensory-evoked potential monitoring is suggested whenever possible for any surgical case. There is an increased risk of a perioperative neurological injury when baseline monitoring cannot be established.33 The intraopera- tive changes in neurological monitoring that do not return to baseline may be investigated further by performing a wake- up test.34,35 At our institution, we also perform a wake-up test at the end of each deformity case to minimize any chance of a neurological deficit. The ability to perform wake-up tests even on younger patients has been shown effective.36 The postoperative monitoring of a patient`s neurological status also remains paramount, given that paraplegia after deformity surgery may present in a delayed fashion, especially in theFIGURE 5. A, Preoperative MRI scan taken from a patient with first 72 hours.35,37congenital kyphoscoliosis causing cord compression (arrow)and myelopathy. B, Postoperative MRI scan showing the SPINAL INSTRUMENTATIONdecompression of the spinal cord after partial apical The use of spinal instrumentation for congenital spinevertebral resection (arrow). deformities has evolved since the description by Hall et al38 in 1981. Newer, downsized implants are available, whereas titanium implants have allowed for increased MRI compat-with progressive deformities, major extremity anomalies, ibility. Hedequist et al39 studied the use of downsizedabnormal reflexes, or neurological deficits are best evaluated instrumentation in patients with congenital spine deformities.with a spinal MRI. We have also found magnetic resonance In that series, the average patient was aged 3.3 years, with aimaging helpful in documenting any canal stenosis or cord preoperative Cobb measurement of 41 degrees; all patientsimpingement in patients with kyphoscoliosis, both as a were treated with an instrumented fusion. There were nopreoperative and a postoperative measure to determine the neurological complications; the implant maintained correc-efficacy of decompression (Fig. 5). tion in the coronal plane and, at follow-up after more than Patients undergoing operative treatment of their spinal 2 years, there were no pseudarthroses. They concludeddeformity may benefit from specialized radiographs before that instrumentation was safe and effective in congenitalsurgery to determine the flexibility of the spine. These scoliosis even in the youngest of patients. This data wasradiographs include traction views, push-prone views, supine further elucidated in a study of 103 patients with congenitalbending films, and films over a bolster. These curves help spine deformities treated with instrumentation at an agedetermine flexibility and help determine the stable vertebra younger than 18 years. In this series, the pseudarthrosisfor instrumentation. rate and the curve correction were similar to those in the previously described series, with no reported neurological SURGICAL PRINCIPLES abnormalities.40 Surgical treatment of patients with congenital spinal The efficacy of instrumentation in congenital deformitydeformities carry a risk of neurological injury greater than surgery was supported by Ruf and Harms41 who studiedthat of patients with idiopathic spinal deformity.31 The newer generation implants in younger patients during poste-occurrence of a perioperative neurological deficit may be rior-only hemivertebra resection. They found that instrumen-minimized in multiple ways, the first being the routine use of tation could be safely used in this population. They furtherMRI evaluation of the spinal cord. The risk of neurological studied spinal implants in younger patients by looking at theinjury from surgical manipulation of a congenital spine efficacy of pedicle screws in patients younger than 2 years.42deformity with an associated spinal cord anomaly may be Screw insertion was safe and feasible in 1-year-old patients;reduced by earlier treatment of the spinal cord anomaly. in addition, they found no instances of canal stenosisOccasionally, neurosurgical treatment may be performed at associated with instrumentation crossing the neurocentral* 2007 Lippincott Williams & Wilkins 109 Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
  5. 5. Hedequist and Emans J Pediatr Orthop & Volume 27, Number 1, January/February 2007synchondrosis. Kim et al,43 in a study of patients with achieved acutely at the time of the initial procedure using acongenital kyphosis, found that the use of spinal implants corrective postoperative cast. The total correction obtained byincreased union rate and maintained curve correction bet- performing a convex hemiepiphysiodesis varies because theter than in the case of uninstrumented patients. Thus, we younger the child at the time of the operation, the morerecommend that newer, downsized implants be safely used potential that exists for correction over time. In general, thisin patients with congenital spine deformities. We also procedure should be reserved for patients younger than 5 yearsrecommend that implants, if at all possible, should be who have modest deformity, given that the long-term resultstitanium, given the increased use of MRI for monitoring not yield less than 15 degrees of total correction, with someonly spinal dysraphism but also cardiac disease and patients obtaining no correction.51 Possibly more predictablegenitourinary anomalies.44 alternatives to convex hemiepiphysiodesis include hemiver- tebra resection or wedge resection, when the deformity FUSION IN SITU involves a short segment of spine, and growth-oriented proce- In situ fusion is a safe technique and a good choice for dures, such as VEPTR placement or growing rods insertion,many progressive curves with minimal deformity involving a when a longer segment of spine is involved.relatively short section of the spine.45 Prophylactic in situfusion may be justified for fully segmented hemivertebra, HEMIVERTEBRA EXCISIONgiven that the rates of progression for these deformities are Hemivertebra excision remains a safe and effective toolextremely high.15 In situ arthrodesis over a short segment of for treating an isolated hemivertebra that produces curvethe spine for these types of deformity is associated with only progression and causes truncal imbalance. The options of inlimited loss in spinal height and good long-term results, even situ fusion and convex epiphysiodesis have been shownwhen performed in younger children.46 Successful arthrod- reliable at obtaining a growth arrest and stopping curveesis is based on thorough facet resection, decortication, and progression; however, they afford no correction of deformityplacement of abundant bone graft. The use of spinal and truncal imbalance.51,52 The optimal indication forinstrumentation has been shown safe and efficacious in hemivertebra resection remains the same: a patient youngeryounger children with congenital scoliosis, probably than 5 years with a thoracolumbar, lumbar, or lumbosacralincreases the fusion rate, and may diminish the time needed hemivertebra and associated truncal imbalance. The surgicalin a brace or a cast.39 Given the paucity of graft available technique of hemivertebra excision varies from stagedfrom the iliac crest in smaller children, allograft is an anterior and posterior procedures to isolated posteriorattractive alternative and has been shown effective in wedge resections, with the decision based on the experienceobtaining fusion.40 and preference of the surgeon.53,54 The need for an anterior fusion with disk excision and a The excision of a hemivertebra may be performed byposterior in situ fusion and arthrodesis depends on the growth using combined anterior and posterior procedures. Thispotential of disks viewed anteriorly, the amount of growth technique allows for the circumferential exposure of theremaining, and the magnitude and direction of curvature. The spine, with the ability to obtain a complete excision of thedisk quality and, by inference, the growth potential of the disks above and below the hemivertebra. Anterior andadjacent vertebral endplates may be evaluated using plain posterior exposure of the spine may be performed asradiographs and preoperative MRI and CT scans. Although sequential procedures under a single anesthetic. Althoughthe disk spaces are frequently small remnants, the failure to this affords excellent visualization, the operative time tendsperform an anterior procedure in the face of healthy disks to be longer, given the magnitude of the surgery and the needmay lead to the crankshaft phenomena, with progression of to reposition and drape the patient.55 Anterior and posteriorcurvature in the face of a solid posterior arthrodesis.47,48 In exposure has been shown effective for hemivertebra excisionlordotic deformities, anterior-only in situ fusion may be when performed as simultaneous procedures. Hedequist etpreferable and sufficient to arrest progression. Kyphotic al56 reported on their series of 18 patients treated by means ofdeformities may profit most from posterior-only fusion, with simultaneous exposures with excision and instrumentation.anticipated anterior growth and slow deformity improvement The average age of the patients was 3 years, with an averageoccurring relative to a posteriorly created tether. The anterior curve correction of 70%. There were no neurologicalprocedure may be performed either through an anterior, open complications, and all patients obtained fusion from thetechnique, thoracoscopically, or through a posterior approach index operation.via the pedicles, depending on the location of the anomaly Posterior-only hemivertebra excision in growing chil-and the preference of the surgeon.49,50 dren has recently been reported with successful results.54,57 We have found the ideal indication to be the hemivertebra CONVEX HEMIEPIPHYSIODESIS located at the thoracolumbar junction or in the lumbar spine, Convex hemiepiphysiodesis, as the name implies, is a with some associated kyphosis. Ruf and Harms54 reportedpartial growth arrest procedure. For this procedure to be their results on hemivertebra excision using posterior-onlyeffective, little or no concave growth potential. Thus, failures approach and segmental transpedicular instrumentation. Theyof segmentation with no little or no growth potential cannot reported excellent results in patients younger than 6 years,be successfully treated this way. The most common with an average Cobb measurement of 45 degrees. At 3.5 yearsindication is a unilateral failure of formation, a hemivertebra. follow-up, the Cobb measurement had been maintained atMuch of the correction associated with this procedure is 14 degrees, with no patient having a neurological complication.110 * 2007 Lippincott Williams & Wilkins Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
  6. 6. J Pediatr Orthop & Volume 27, Number 1, January/February 2007 Congenital Scoliosis: A Review and UpdateShono et al58 reported on their experience involving 12 pa- studies and has significant remaining growth; this patienttients treated with hemivertebra excision and segmental may be at risk of crankshaft and should have either an openinstrumentation during adolescence. Their correction rate was or a thoracoscopic anterior release and fusion.47 (2) The64%, with all patients obtaining fusion and no patient having patient has a moderately sized deformity, has well-defineda neurological deficit. The posterior resection of hemivertebra disks on imaging studies, and has less flexibility as revealedis a demanding procedure that may be performed safely by by bending radiographs. An anterior procedure withexperienced hands with good correction rate and minimal discectomies and bone grafting performed in these patientsneurological risk. aids in obtaining a well-balanced spine and aids in helping obtain fusion. The correction of more severe deformities may be CORRECTION AND FUSION WITH significantly more challenging with a greater prevalence of INSTRUMENTATION neurological compromise. Osteotomies of vertebral congeni- Partial or complete correction of a congenital spine tal fusions and bars may aid in correction but are also fraughtdeformity may be possible by means of arthrodesis and with more risks associated with either direct or indirect cordinstrumentation. The partial or complete correction of a injury and significant intraoperative hemorrhage.57,59 Thedeformity is based on the congenital anomaly itself, the surgery for these deformities may be either combined anteriordegree of deformity, and the magnitude of surgery. The stable and posterior procedures or posterior-only procedures withzones of operation may be defined by the standing spinal instrumentation (Fig. 6). Anterior surgery for more severeradiographs, with additional information regarding the deformities should be performed as an open procedure, withflexibility of the anomaly and the adjacent spine deemed by discectomies and osteotomies at a single level or multiplebending x-rays or traction x-rays. levels being performed, depending on the degree of Congenital anomalies associated with relatively normal deformity. The addition of anterior surgery to a posteriorsegmentation, flexibility (as revealed by radiographs), and procedure may be conducted at the same anesthetic or as aless severe truncal deformity may be managed by means of separate procedure, depending on the magnitude of surgery.standard posterior arthrodesis and instrumentation. The use Posterior-only procedures, such as pedicle subtractionof modern neurological monitoring techniques and good osteotomies or vertebral column resection, offer correction ofsurgical technique allows this to be a relatively safe surgical severe deformities without a separate anterior surgicaloption for mild to moderate deformities.39,40 The addition of approach. These procedures are technically demanding andanterior surgery in these cases may be done in 2 situations are associated with significant blood loss and neurological(1) The patient has well-defined disk spaces seen on imaging risk. The use of pedicle subtraction techniques as used inFIGURE 6. A, Plain radiograph depicting significant coronal imbalance in a patient with multiple congenital anomalies(arrows). B and C, Postoperative radiographs depicting coronal and sagittal balance after anteroposterior surgery with osteotomiesand instrumentation.* 2007 Lippincott Williams & Wilkins 111 Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
  7. 7. Hedequist and Emans J Pediatr Orthop & Volume 27, Number 1, January/February 2007adults for kyphotic deformity may be beneficial.57,59 The series of 16 patients treated in this manner for congenitaldisadvantages of posterior-only procedures include the kyphosis. Vertebral resection or osteotomies were performeddifficulty with anterior column visualization during any using a costotransversectomy approach, with satisfactoryperiod of significant blood loss, the need for spinal cord and results in 13 of 16 patients. In their series, the mean kyphosisdural manipulation, and the potential for perioperative was corrected from 65 to 34 degrees, and instrumentation wasdisplacement at the osteotomy site. Planning of circumfer- used in all but 1 patient. The authors concluded that forential osteotomies should be conducted preoperatively by complex kyphotic deformities of the thoracic spine, costo-using 3-dimensional CT to understand the deformity and to transversectomy should be considered.anticipate the anomalous anatomy. As with any procedurebeing performed on the spine, the planned osteotomy should TRACTIONbe one that shortens the spinal column and relies on Congenital spine deformities occasionally present ascompression rather than on distraction and lengthening. rigid, severe curves, which may be impossible to correct Anterior access to the spinal column may be most using standard instrumentation techniques. The safety ofreadily managed by using a posterior approach when there is traction in congenital spine deformities, particularly in casesan associated kyphosis or extreme degrees of rotation.57,59Y61 involving preexisting neurological deficits, has been ques-A patient with congenital kyphosis or congenital kyphosco- tioned in the past reports by MacEwen et al31 with regard toliosis may require circumferential treatment for curve the risk of traction-induced paraplegia in congenital defor-correction and/or decompression. Given the kyphotic nature mities. Recently, the use of traction has been popularized forof some deformities and the posterior positioning of the apex, severe deformities, including congenital deformities.62,63 Thean anterior surgery may be technically unfeasible, given the use of halo gravity traction has been reported on by Sinkdifficulty of access in a thoracotomy (Fig. 7). Access to the et al62 and then expanded on by Rinella et al63; both series hadanterior column may be provided through a costotransverse- no permanent neurological deficits. Halo gravity tractionctomy, which allows access to the anterior portion of the allows patients to have gradual weight applied to the halo ringspine through a posterior incision. Smith et al61 reported on a either while in bed or while in a wheelchair or walker device. Weight is applied daily until partial curve correction is attained; any evidence of neurological demise calls for decreasing the traction weight. This technique allows for some gradual curve correction before an operation. It may be used before or after an associated anterior release. Halo-femoral traction has recently been described by Mehlman et al.64 They used this method of traction after an associated spinal release and described the technique they used on 24 patients, with an average pretraction radiograph of 95 degrees and a posttraction radiograph of 44 degrees. The patients were maintained in traction at an average of 54% of body weight. The final curve correction was 71% with no permanent neurological deficits. FUSIONLESS SURGERY Patients younger than 5 years who have congenital deformities involving long sections of the spine or with large compensatory curves in normally segmented regions present a great challenge for treatment. In the past, the early arthrodesis of the spine was thought to be beneficial and to have a tolerable effect on sitting and trunk height.46 However, recent studies have shown that early arthrodesis over a section of the thoracic spine before the age of 5 years may be associated with a significant reduction in pulmonary function.65 The growth of the spine is greatest during the first 5 years of life as sitting height reaches two thirds of the adult level by age 5, whereas the thorax has achieved less of its adult volume. Congenital scoliosis is associated with short stature and diminished trunk height. Long fusions performed onFIGURE 7. Preoperative 3-dimensional CT scan, taken from apatient with congenital kyphoscoliosis, depicting the potential younger children may have a further deleterious effect ondifficulty in obtaining apical access through an anterior trunk height and thoracic volume, leading to thoracicapproach. This patient was treated with a decompression insufficiency. In the absence of congenital rib fusions, treatingprocedure via costotransversectomy and fusion with spinal patients with early progressive deformities may best beinstrumentation. conducted by using a growing rod technique.112 * 2007 Lippincott Williams & Wilkins Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
  8. 8. J Pediatr Orthop & Volume 27, Number 1, January/February 2007 Congenital Scoliosis: A Review and Update Surgically, the treatment of deformity by way of proximally and distally after subperiosteal dissection and addinstrumentation without fusion was first pioneered by Paul bone graft to obtain fusion at the anchor sites. Dual rods,Harrington66 in the 1960s. His experiences led him to believe connected to the anchor points, are placed deep to thethat a definitive fusion should not be performed before age 10 muscular fascia to obtain partial correction, and thenand that instrumentation without fusion should be considered lengthened every 4 to 6 months. We have found this usefulin younger patients. Moe et al67 then reported their technique in occasional patients with congenital spine deformities.of limited exposure in the placement of implants, with Preoperative evaluation via plain film and 3-dimensional CTresultant growth seen in the instrumented areas of the spine. scanning has been useful to determine whether the anatomySeveral authors have continued to study this technique and, will allow for the placement of proximal and distal anchors.recently, Blakemore et al68 reported on the technique they In general, the technique is most useful in patients who haveused on a heterogeneous group of patients with newer compensatory curves in normally segmented regions abovegeneration implants. They reported improvement on Cobb and below the congenital anomalies, allowing for anchorangles and sagittal contouring in the patients, although the placement and relying on growth through more normallyfinal growth measurements were not reported. segmented areas (Fig. 8). The problems associated with a single-rod implant, For a patient with progressive curves that either haveincluding hook dislodgement and rod breakage, have led congenital anomalies that will not allow for anchor placementAkbarnia et al69 to report their series of a dual growing rod or have associated congenital rib fusions that requireconstruct. This is performed by subperiosteal dissection of the thoracostomy, we will choose expansion thoracostomy andanchor sites proximally and distally and by placement of claw VEPTR.constructs. Rods are then placed subcutaneously on each sideand joined with tandem connectors placed at the thoraco- EXPANSION THORACOPLASTY AND VEPTRlumbar junction, where the lengthening may occur. Their Congenital spine deformities with rib fusions may bepatients had an average Cobb angle improvement from 82 to associated with a constricted thorax, leading to poor thoracic38 degrees at follow-up and an average growth of the T1-S1 and lung parenchymal growth and to thoracic insufficiency.segment of 1.2 cm per year. Thompson et al70 have reported This term has been coined by Dr Robert Campbell to describefurther on this technique, with encouraging results on dual a continuum of problems associated with spine and chestrods without apical fusion. Although these reports have not growth that lead to the inability to support normal lungbeen about homogenous groups of patients and include function and growth.13 The tethering effect of congenital riblimited numbers of patients with congenital scoliosis, the fusions add to the scoliotic effect of the spine to produce aresults are interesting and the technique merits attention. concave, constricted hemithorax, which is diminished in For patients with congenital deformities involving long height and function.19 Campbell has also described theregions of the spine, we have thought that this procedure is a Bwindswept thorax,[ in which progressive thoracic scoliosisgood surgical option. At our institution, we place anchors and rotation lead to a foreshortened hemithorax on the concave side and a collapsed hemithorax on the convex side of the severe scoliosis. The growth of the lung, respiratory branches, and alveoli is greatest in the first 8 years of life. Fifty percent of the thoracic volume is obtained by age 10; thus, early fusions may have an even more profound effect on thoracic development than on spine height.20 The possible effect of early spinal fusion on thoracic development may compound the preexisting thoracic insufficiency associated with congenital scoliosis and fused ribs.13 This interdepen- dent relationship of the spine and the chest wall has led to the development of expansion thoracoplasty and VEPTR place- ment as a possible treatment of congenital spine deformities with associated chest wall anomalies.71,72 The evaluation of these patients is similar to that of all patients with congenital spine deformities; however, they need additional studies to document lung volumes and pulmonary function tests. Younger children are not able to reliably perform pulmonary function tests; however, their pulmonary function can be gleamed from the data obtained by 3-dimensional CT scanning.28,73 Gollogly et al28 published a series on younger patients with thoracic insufficiency whoFIGURE 8. A, Preoperative radiograph taken from a 2-year-oldpatient with congenital scoliosis and rib fusions (arrows). Note were being treated with expansion thoracoplasty. Theirthe hypoplastic right hemithorax, B, Postoperative radiograph results indicated that measurements of lung volumes couldfrom the same patient after expansion thoracoplasty predictably be performed using data obtained from the 3-and VEPTR placement. Note the improvement in the volume dimensional reconstruction of CT scan data. These studiesof the right hemithorax. could also be conducted postoperatively to quantify an* 2007 Lippincott Williams & Wilkins 113 Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
  9. 9. Hedequist and Emans J Pediatr Orthop & Volume 27, Number 1, January/February 2007 to those patients with congenital scoliosis and chest wall deformities that require surgical intervention to control both deformities and to allow growth. SUMMARY The treatment of congenital scoliosis focuses on early diagnosis and appropriate surgical management before the development of large curves. Vertebral anomalies that have a natural history of progression need to be managed aggres- sively. All patients with the diagnosis of congenital scoliosis need a preoperative screening MRI of the spinal axis and a screening evaluation for renal and cardiac anomalies. The hallmark of treatment remains to be the early diagnosis before the development of a large curve. The surgical treatment options include in situ fusion procedures and convex hemiepiphysiodesis in those cases where a progressive curve is present in the face of minimal or no deformity. Moderate deformities may be partially corrected throughFIGURE 9. A, Radiograph taken from a 4-year-old patient with instrumentation and arthrodesis, whereas more severea lumbosacral hemivertebra and lumbar congenital vertebral deformities may be managed by corresponding osteotomiesanomalies (arrows). Note the large amount of curvature or vertebrectomies. Surgical correction of congenital spinalthrough normally segmented spine. B, Postoperative deformity carries significant risk of neurological injury,radiograph from the same patient after the insertion of bilateral making early, simple treatment preferable. Thoracic insuffi-growing rods with upper thoracic and pelvic anchors. ciency syndrome associated with congenital scoliosis and fused ribs is perhaps best managed during growth byincrease in the volume of lung parenchyma after expansion expansion thoracostomy and insertion of expandablethoracoplasty. VEPTR devices. Growing rods may be used in younger Expansion thoracoplasty is a technique that involves patients with severe curves involving long areas of normallythe expansion of the hemithorax by osteotomizing the segmented spine. The use of neurological monitoring issegments of congenitally fused ribs or the areas of rib paramount during any surgical procedure because the goaladhesions between anomalous sections of ribs.72 The surgical remains the same: to achieve a balanced spine with notechnique involves a standard thoracotomy incision with resultant neurological deficit.division of the latissimus and the serratus. Once exposed, theareas on constriction may be isolated and then osteotomized REFERENCESby using a rongeur and a craniotome. Once the osteotomy or 1. Shands AR Jr, Bundens WD. Congenital deformities of the spine: anlysis of adhesions is done, the area may be opened with analysis of the roentgenograms of 700 children. Bull Hosp Jt Dis.lamina spreaders. 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Maisenbacher MK, Han JS, O`Brien ML, et al. Molecular analysis ofwith thoracic insufficiency and fused ribs; they found that the congenital scoliosis: a candidate gene approach. Hum Genet. 2005;growth of the thoracic spine after expansion was similar to 116:416Y419.that in healthy controls. They also found that the increased 9. von Koch CS, Glenn OA, Goldstein RB, et al. Fetal magnetic resonance imaging enhances detection of spinal cord anomalies in patients withvolume of the constricted hemithorax and the total lung sonographically detected bony anomalies of the spine. J Ultrasoundvolumes obtained during expansion were maintained at Med. 2005;24:781Y789.follow-up. In general, we have found this treatment beneficial 10. Griffiths PD, Paley MN, Widjaja E, et al. In utero magnetic resonance114 * 2007 Lippincott Williams & Wilkins Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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J Bone Joint Surg Am. 2006;88:1043Y1052. 2003;85-A:409Y420. 56. Hedequist DJ, Hall JE, Emans JB. Hemivertebra excision in children via31. MacEwen GD, Bunnell WP, Sriram K. Acute neurological complications simultaneous anterior and posterior exposures. J Pediatr Orthop. in the treatment of scoliosis. A report of the Scoliosis Research Society. 2005;25:60Y63. J Bone Joint Surg Am. 1975;57:404Y408. 57. Shimode M, Kojima T, Sowa K. Spinal wedge osteotomy by a single32. Talu U, Gogus A, Tezer M, et al. Simultaneous surgical treatment for posterior approach for correction of severe and rigid kyphosis or congenital scoliosis or kyphosis and intramedullary abnormalities [paper kyphoscoliosis. Spine. 2002;27:2260Y2267. 68]. Presented at: Scoliosis Research Society Annual Meeting; 58. Shono Y, Abumi K, Kaneda K. One-stage posterior hemivertebra September 10Y13, 2003; Quebec City, Canada. resection and correction using segmental posterior instrumentation.33. 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  11. 11. Hedequist and Emans J Pediatr Orthop & Volume 27, Number 1, January/February 2007 deformity: follow-up period longer than ten years. Spine. 2002;27: curvature problems in young children. Clin Orthop Relat Res. 1984: 110Y115. 35Y45.61. Smith JT, Gollogly S, Dunn HK. Simultaneous anterior-posterior 68. Blakemore LC, Scoles PV, Poe-Kochert C, et al. Submuscular Isola approach through a costotransversectomy for the treatment of congenital rod with or without limited apical fusion in the management of severe kyphosis and acquired kyphoscoliotic deformities. J Bone Joint Surg Am. spinal deformities in young children: preliminary report. Spine. 2001; 2005;87:2281Y2289. 26:2044Y2048.62. Sink EL, Karol LA, Sanders J, et al. Efficacy of perioperative 69. Akbarnia BA, Marks DS, Boachie-Adjei O, et al. Dual growing rod halo-gravity traction in the treatment of severe scoliosis in children. technique for the treatment of progressive early-onset scoliosis: a J Pediatr Orthop. 2001;21:519Y524. multicenter study. Spine. 2005;30:S46YS57.63. Rinella A, Lenke L, Whitaker C, et al. Perioperative halo-gravity traction in 70. Thompson GH, Akbarnia BA, Kostial P, et al. Comparison of single and the treatment of severe scoliosis and kyphosis. Spine. 2005;30:475Y482. dual growing rod techniques followed through definitive surgery: a64. Mehlman CT, Al-Sayyad MJ, Crawford AH. Effectiveness of spinal preliminary study. Spine. 2005;30:2039Y2044. release and halo-femoral traction in the management of severe spinal 71. Campbell RM Jr, Smith MD, Mayes TC, et al. The effect of opening deformity. J Pediatr Orthop. 2004;24:667Y673. wedge thoracostomy on thoracic insufficiency syndrome associated with65. Emans JB, Kassab F, Caubet JF, et al. Earlier and more extensive fused ribs and congenital scoliosis. J Bone Joint Surg Am. 2004;86-A: thoracic fusion is associated with diminished pulmonary function. 1659Y1674. Outcome after spinal fusion of 4 or more thoracic spinal segments before 72. Campbell RM Jr, Smith MD, Hell-Vocke AK. Expansion thoracoplasty: age 5 [paper 101]. Presented at: Scoliosis Research Society Annual the surgical technique of opening-wedge thoracostomy. Surgical Meeting; September 6Y9, 2004; Buenos Aires, Argentina. technique. J Bone Joint Surg Am. 2004;86-A(suppl 1):51Y64.66. Harrington PR. Scoliosis in the growing spine. Pediatr Clin North Am. 73. Gollogly S, Smith JT, White SK, et al. The volume of lung parenchyma 1963;10:225Y245. as a function of age: a review of 1050 normal CT scans of the chest with67. Moe JH, Kharrat K, Winter RB, et al. Harrington instrumentation without three-dimensional volumetric reconstruction of the pulmonary system. fusion plus external orthotic support for the treatment of difficult Spine. 2004;29:2061Y2066.116 * 2007 Lippincott Williams & Wilkins Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.