The Association Between the Utilization of Traction and Postoperative Complications Following Growing Rod Instrumentation for Early-onset Scoliosis.

BACKGROUND: Preoperative and/or intraoperative traction have been proposed as adjunctive methods to limit complications associated with growth-friendly instrumentation for early-onset scoliosis (EOS). By gradually correcting the deformity before instrumentation, traction can, theoretically, allow for better overall correction without the complications associated with the immediate intraoperative correction. The purpose of this multicenter study was to investigate the association between preoperative/intraoperative traction and complications following growth-friendly instrumentation for EOS. METHODS: Patients with EOS who underwent growth rod instrumentation before 2017 were identified from 2 registries. Patients were divided into 2 groups: preoperative traction group versus no preoperative traction group. A subgroup analysis was done to compare intraoperative traction only versus no traction. Data was collected on any postoperative complication from implantation to up to 2 years postimplantation. RESULTS: Of 381 patients identified, 57 (15%) and 69 (18%) patients received preoperative and intraoperative traction, respectively. After adjusting for etiology and degree of kyphosis, there was no evidence to suggest that preoperative halo traction reduced the risk of any complication following surgical intervention. Although not statistically significant, a subgroup analysis of patients with severe curves demonstrated a trend toward a markedly reduced hardware failure rate in patients undergoing preoperative halo traction [preoperative traction: 1 (3.1%) vs. no preoperative traction: 11 (14.7%), P=0.083]. Nonidiopathic, hyperkyphotic patients treated with intraoperative traction were 61% less likely to experience any postoperative complication (P=0.067) and were 74% (P=0.091) less likely to experience an unplanned return to the operating room when compared with patients treated without traction. CONCLUSIONS: This multicenter study with a large sample size provides the best evidence to date of the association between the use of traction and postoperative complications. Our results justify the need for future Level I studies aimed at characterizing the complete benefit and risk profile for the use of traction in surgical intervention for EOS. LEVEL OF EVIDENCE: Level III.

Serial Casting in Neuromuscular and Syndromic Early-onset Scoliosis (EOS) Can Delay Surgery Over 2 Years.

BACKGROUND: The primary goal in managing early-onset scoliosis (EOS) is delaying/preventing surgical intervention while allowing improved spinal growth and chest wall and lung development to improve life expectancy. The effectiveness of serial casting for patients with neuromuscular and syndromic EOS is unclear. METHODS: Patients from 2 multicenter registries who underwent serial casting for nonidiopathic scoliosis (NIS) were reviewed retrospectively. Comparisons were made between precasting and postcasting major and compensatory curves and spine height. The need for surgical intervention and any treatment complications were documented. Risk factors for major curve progression from baseline to casting cessation were evaluated via univariate analysis. RESULTS: Forty-four patients (23 females; 21 males) with NIS (26 syndromic, 18 neuromuscular) and a mean age of 3.2 years at baseline were included. Mean follow-up and casting duration was 3.9 and 2.0 years, respectively. There were no statistically significant differences between mean precasting and postcasting major curve (55 vs. 60 degrees; P=0.348), minor curve (31 vs. 33 degrees; P=0.510), or rib-vertebra angle difference (18 vs. 29 degrees; P=0.840). However, thoracic height (15.5 vs. 16.8 cm; P=0.031) and lumbar height (8.9 vs. 9.8 cm; P=0.013) were significantly greater upon casting cessation. Currently, 13 patients (30%) have had successful casting (improvement of major curve ≥10 degrees) while 24 patients (55%) experienced major curve progression (worsening), and 19 patients (43%) required surgical intervention. Mean time from first casting to surgery was 34.5±15.1 months. There were no statistically significant predictors for major curve progression on univariate analysis. CONCLUSIONS: Spinal deformity progression despite casting and the subsequent need for surgical intervention for NIS were significantly higher compared with those reported for idiopathic EOS. However, serial casting did afford a substantial delay in surgical intervention. Ultimately, serial casting for neuromuscular or syndromic EOS is an effective strategy for delaying surgical intervention, despite suboptimal radiographic outcomes. LEVEL OF EVIDENCE: Level III.

Serial Mehta Cast Utilization in Infantile Idiopathic Scoliosis: Evaluation of Radiographic Predictors.

BACKGROUND: Mehta cast utilization has gained a considerable momentum as a nonoperative treatment modality for the initial management of infantile idiopathic scoliosis (IIS). Despite its acceptance, there is paucity of data that characterize the radiographic parameters associated with Mehta casting and the factors correlated with a sustained curve correction. METHODS: A retrospective review of IIS patients who underwent Mehta casting was performed with a mean 2-year follow-up. X-rays were evaluated at each visit for the Cobb angle, focal deformity, rib-vertebral angle difference, and height of concavity and convexity of the apical 3 vertebrae. Concave-to-convex height ratios were calculated and tracked for each patient. Radiographic parameters were compared from precasting to after final casting, and from final casting to most recent follow-up. RESULTS: A total of 45 patients were identified, of whom 18 (40%) were male and 27 (60%) were female, with a mean age of 18.8±9.5 months at first casting and a mean follow-up of 37.7±19.7 months. Following final casting, the mean Cobb angle (25.6 vs. 52.7 degrees), focal deformity (17.4 vs. 30.5 degrees), rib-vertebral angle difference (18 vs. 32.3 degrees), and the concave-to-convex height ratios improved relative to precast parameters, respectively (P<0.001). At final follow-up, mean Cobb angle (16.2 vs. 25.6 degrees) and concave-to-convex height ratios progressively improved when compared with final cast measurements, respectively (P<0.001). Five (11%) patients did not demonstrate sustained curve correction at final follow-up, whereas 4 (9%) required growing-rod placement. Lastly, the regression analysis demonstrated improvements in the focal deformity (17.4 vs. 30.5) and the concave-to-convex height ratios of the +1 and -1 apical vertebrae from the precast to last cast periods (P<0.001). These findings were correlated with sustained Cobb angle correction from cast removal to the most recent follow-up. CONCLUSIONS: Radiographic parameters associated with control of progressive deformity for IIS include improvements in focal deformity and concave-to-convex height ratios for +1 and -1 apical vertebrae after final casting. Mehta casting is an effective treatment for symptomatic IIS and continues to provide IIS patients with significant curve correction. LEVEL OF EVIDENCE: Level IV.

The efficacy of preoperative halo-gravity traction in pediatric spinal deformity the effect of traction duration.

STUDY DESIGN: Retrospective case review OBJECTIVE: To assess the appropriate length of halo-gravity traction that provides the most preoperative correction and minimizes halo associated complications. SUMMARY OF BACKGROUND: Rapid correction of severe scoliosis increases the risk of neurological compromise. To minimize complications, some patients undergo preoperative halo traction providing gradual correction before definitive management. The appropriate length of traction to provide the most preoperative correction is unknown. METHODS: Twenty pediatric patients (age: range, 220 y, average 11.2 y) with severe operative scoliosis, kyphoscoliosis, or kyphosis were retrospectively studied. The major structural coronal curves before traction (n = 11 patients, 19 curves, range 44128 degrees, average 84.7 degrees) or immediately after anterior release (n = 7 patients, 10 curves, range 3598 degrees, average 67.7 degrees) were measured as well as weekly during traction and postoperatively at 1 year. Sagittal kyphosis (n = 12 patients, range 60143 degrees, average 97.6 degrees) was measured at the same time intervals. Patients in traction(maximum traction weight range 15.5% to 46.5% of bodyweight, average 32.9%) for a duration of at least 3 weeks (range 310.5 wk, average 4.6 wk) were included. Patients with prior surgical fusion were excluded; however, patients who under went a stage anterior-posterior were included. Halo-traction related complications were noted in each case. RESULTS: The major coronal and sagittal curve corrected 66.3% and 62.7% (change in curve per week/total change in curve), respectively at 2 weeks (n = 29, 12 curves), 21.7% and 24.3% at 3 weeks (n = 29, 12), and 7.5% and 15.9% at 4 weeks (n = 14,6). Traction-related complications during the traction duration included 2 cases of ileus, 1 respiratory complication, 2 pin loosening, and 1 superficial pin infection. CONCLUSION: The treatment of severe scoliosis can be very challenging. The use of long-term halo traction preoperatively can assist in the surgical correction. The majority of correction occurs during the first 2 weeks of traction. No permanent neurological complications occurred during traction.

Subclavian vein thrombosis after application of body cast.

Mehta-Cotrel body casting is a well-recognized and effective technique for the treatment of progressive infantile scoliosis. The treatment can be challenging to execute given the commitment required by the patient's family and treatment team, and is not without complications. In this report, we detail the occurrence of a subclavian vein thrombosis after the placement of a Mehta-Cotrel cast for the treatment of progressive infantile kyphoscoliosis. To date, this is a previously unreported complication after body casting. Expeditious and accurate diagnosis of this complication leads to effective treatment without further morbidity. Therefore, clinicians using body casting for the treatment of scoliosis should be aware of the possibility of this complication and know how to quickly diagnose and treat it.

Challenges of spine surgery in patients with chondrodysplasia punctata.

BACKGROUND: Chondrodysplasia punctata (CDP) is a common manifestation of an etiologically heterogenous group of disorders. There is very little data regarding the development and management of spinal deformity in patients with CDP. The purpose of this study was to present a multicenter series of CDP, to describe the surgical outcomes of spinal deformities in CDP patients and to emphasize important considerations that may influence choice of surgical treatment of spinal deformity in this patient population. METHODS: The medical records and spinal radiographs of patients with the diagnosis of CDP followed in 2 centers between 1975 and 2011 were retrospectively reviewed. Epiphyseal stippling was present on radiographs in all patients who fulfilled the clinical criteria. RESULTS: Among the 17 patients who were diagnosed with CDP, 13 had spinal deformities. The mean age at diagnosis of spinal deformity was 14.6 months (range, 1 wk to 9 y). Males and females were close to equally represented (10 males and 7 females). Twelve patients (92%) required surgery to correct spinal deformity. Patients were followed for a median of 8.4 years (range, 2.8 to 19.5 y). The total number of surgical procedures performed was 17 averaging 1.5 per patient. Four patients required >1 procedure. Eighty percent of the patients who required >1 surgical procedure were females with probable diagnosis of X-linked dominant CDP. Revision surgery was indicated in 50% of the patients treated with combined anterior and posterior fusion and 20% of the patients treated with posterior fusion alone. CONCLUSIONS: Spinal deformity in CPD patients may range from significant kyphoscoliosis to minimal deformity that does not require any treatment. For those patients in whom spine surgery was indicated, a high incidence of revision surgery and curve progression after fusion was recorded. Female patients with probable diagnosis of X-linked dominant CDP were more likely to require a second surgical procedure. Isolated posterior fusion showed less favorable results compared with combined anteroposterior fusion in terms of revision surgery. LEVEL OF EVIDENCE: Level IV-therapeutic study.

Intraoperative techniques to reduce the potential of set-screw loosening in long spinal constructs: a static and fatigue biomechanical investigation.

STUDY DESIGN: The purpose of this study was to investigate the effects of implant selection and set-screw tightening technique on the loosening torques in long scoliosis constructs after long-term biaxial fatigue loading. SUMMARY OF BACKGROUND DATA: Expanded use of pedicle screws in the correction of long scoliotic curves and the mechanical demands on segmental fixation systems requires surgeon awareness of revisiting set screws to ensure full screw/rod engagement and minimize the potential of set-screw loosening and/or rod slippage postoperatively. METHODS: Biomechanical tests were performed to evaluate the effect of set-screw tightening techniques and rod approximation on screw/rod interface strength. RESULTS: Rod reduction test shows the force required to approximate a rod to a pedicle screw is statistically lower with uniplanar or polyaxial screws, when compared with monoaxial screws. This ease of approximation in both polyaxial and uniplanar screws directly correlate to improvement in the axial slippage resistance. In the simulated spinal model construct, rod/screw securement can vary based on the number of tightening torques applied to the system. CONCLUSIONS: Sequential revisiting of sets crews in long scoliosis constructs resulted in a statistically significant increase in loosening torque for monoaxial and polyaxial screw systems. Intraoperative securement assessment of set screws is recommended. The use of polyaxial and uniplanar screws at the distal ends in long constructs is recommended to increase the screw/rod interface strength.

Iatrogenic thoracic outlet syndrome secondary to vertical expandable prosthetic titanium rib expansion thoracoplasty: pathogenesis and strategies for prevention/treatment.

BACKGROUND: An innovative treatment for thoracic insufficiency syndrome involves a vertical expansion of the chest wall through a horizontal chest wall osteotomy maintained by a distraction device (vertical expandable prosthetic titanium rib or VEPTR). Upper-extremity neurovascular dysfunction has been reported after expansion. The purposes of this study are to identify potential etiologies for compression of the brachial plexus after expansion thoracoplasty and to suggest strategies to reduce the incidence of this complication. METHODS: A simulated VEPTR procedure was performed on 8 fresh cadaveric specimens. Manometric measurements were taken in the 3 anatomic regions of the thoracic outlet after thoracotomy and rib distraction were performed. Confirmation of the location of compression was performed by placing barium-impregnated putty along the course of the brachial plexus and evaluating the effect of expansion using video fluoroscopy. A midclavicular osteotomy was then performed and video fluoroscopy repeated. RESULTS: A 20% increase in pressure was seen in the costoclavicular region of the thoracic outlet after expansion. Constriction of the midclavicular region of the thoracic outlet between the first rib and clavicle was confirmed using the putty model. Midclavicular osteotomy alleviated this region of compression. CONCLUSIONS: Expansion thoracoplasty with the VEPTR procedure causes increased pressure in the costoclavicular region of the thoracic outlet. A midclavicular osteotomy may be one method to alleviate thoracic outlet narrowing after VEPTR procedure, although the short- and long-term effects of this is procedure is not known. CLINICAL RELEVANCE: Our model supports an iatrogenic thoracic outlet syndrome caused by expansion thoracoplasty. Based on our data as well as a review of the literature, we recommend intraoperative neurologic monitoring of the ipsilateral upper extremity during the VEPTR procedure.

Effects of Spinal Fusion for Idiopathic Scoliosis on Lower Body Kinematics During Gait.

STUDY DESIGN: Prospective. OBJECTIVES: The purpose of this study was to compare gait among patients with scoliosis undergoing posterior spinal fusion and instrumentation (PSFI) to typically developing subjects and determine if the location of the lowest instrumented vertebra impacted results. SUMMARY OF BACKGROUND DATA: PSFI is the standard of care for correcting spine deformities, allowing the preservation of body equilibrium while maintaining as many mobile spinal segments as possible. The effect of surgery on joint motion distal to the spine must also be considered. Very few studies have addressed the effect of PSFI on activities such as walking and even fewer address how surgical choice of the lowest instrumented vertebra (LIV) influences possible motion reduction. METHODS: Individuals with scoliosis undergoing PSFI (n = 38) completed gait analysis preoperatively and at postoperative years 1 and 2 along with a control group (n = 24). Comparisons were made with the control group at each time point and between patients fused at L2 and above (L2+) versus L3 and below (L3-). RESULTS: The kinematic results of the AIS group showed some differences when compared to the Control Group, most notably decreased range of motion (ROM) in pelvic tilt and trunk lateral bending. When comparing the LIV groups, only minor differences were observed, and the results showed decreased coronal trunk and pelvis ROM at the one-year visit and decreased hip rotation ROM at the two-year visit in the L3- group. CONCLUSIONS: Patients with AIS showed decreased ROM preoperatively with further decreases postoperatively. These changes remained relatively consistent following the two-year visit, indicating that most kinematic changes occurred in the first year following surgery. Limited functional differences between the two LIV groups may be due to the lack of full ROM used during normal gait, and future work could address tasks that use greater ROM. LEVEL OF EVIDENCE: Level II.

Paper #13: Early Onset Scoliosis: Results of Cotrel Mehta Casting from a Single Institution.

Early onset scoliosis can lead to significant chest wall deformity resulting in severe restrictive pulmonary disease and premature demise. Treatment of the spinal deformity should control the curvature but allow for continued growth of the spine and thorax. Serial derotational casting can potentially preserve and redirect spinal growth to achieve curve correction.

Effect of Surgical Fusion on Volitional Weight-Shifting in Individuals With Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Prospective. OBJECTIVES: The goals of this study were to (1) evaluate the differences in weightbearing symmetry between individuals with adolescent idiopathic scoliosis (AIS) and typically developing controls; (2) observe the effect of posterior spinal fusion and instrumentation (PSFI) on volitional weight-shifting at 1 and 2 years postoperatively; and (3) evaluate whether lowest instrumented fusion level (ie, lowest instrumented vertebra [LIV]) in PSFI has an effect on volitional weight-shifting. SUMMARY OF BACKGROUND DATA: Previous studies have conflicting findings with regard to the effect of scoliosis on postural control tasks as well as the effect of surgery. They have also noted an inconsistent effect of PSFI at different LIVs, with more distal LIVs exhibiting greater reductions in postoperative range of motion. METHODS: The study was designed with an AIS group of 41 patients (8 males and 33 females) with AIS who underwent PSFI, along with a Control Group of 24 age-matched typically developing participants (12 male and 12 female). Both groups performed postural control tasks (static balance and volitional weight-shifting), with the AIS group repeating the tasks at 1 and 2 years postoperatively. RESULTS: At baseline, the AIS group showed increased weightbearing asymmetry than the Control Group (p = .01). The AIS group showed improvements in volitional weight-shifting at 2 years over baseline (p < .01). There was no effect of LIV on volitional weight-shifting by the second postoperative year. CONCLUSIONS: Individuals with AIS have greater weightbearing asymmetry but improved volitional weight-shifting over typically developing controls. PSFI improves volitional weight-shifting beyond preoperative baseline but does not differ significantly by LIV.

Serial Derotational Casting in Idiopathic and Non-Idiopathic Progressive Early-Onset Scoliosis.

INTRODUCTION: Serial derotational casting has been used as a definitive treatment or as delaying strategy in progressive idiopathic (IS) and non-idiopathic (NIS) early-onset scoliosis (EOS). METHODS: Retrospective chart and radiographic review of patients who underwent serial casting for progressive EOS between 2005 and 2012 at a single institution. RESULTS: A total of 74 consecutive patients entered serial cast treatment. Twenty-eight were currently being casted, 30 completed cast treatment and were converted to thoracolumbosacral orthosis (TLSO), 9 were treated surgically, 6 were lost to follow-up, and 1 had no further treatment. The researchers diagnosed IS in 41 patients; 33 had NIS. At presentation the IS group had an average Cobb angle (CA) of 49° and a rib vertebral angle difference (RVAD) of 37°. The NIS group had a CA of 51° (p = .69) and RVAD of 37° (p = .94). In patients currently being casted, 19 IS patients had a decreased CA, from 47° to 27°. The 9 NIS patients had a decreased CA, from 62° to 57° (p = .0002). Cobb angle improvement was significantly better in IS (p = .0005). In the TLSO group the 17 IS patients had a decreased average CA, from 46° to 18°, after serial casting and the 13 NIS patients decreased CA from 42° to 32°. Patients with IS had better improvement in CA than the NIS group (p < .001). At last follow-up, this was reduced to 11° in the IS group and maintained at 32° in the NIS. In the IS group, 5 of 41 patients were converted to growth constructs, and 4 of 26 in the NIS group. Casting initiated before age 2 years yielded better curve correction for IS (p < .01) compared with NIS. CONCLUSIONS: Progressive idiopathic scoliosis patients had better curve correction with casting than NIS patients. Casting in IS patients before age 24 months yielded better curve correction. Patients who required surgery had a higher age and Cobb angle at presentation than those who transitioned to a TLSO. The surgical group was observed for a similar duration of time and there was no significant statistical difference. Although RVAD is a predictor of progression in infantile IS, it did not show a predictive value in the response to casting of either the IS or NIS groups.

Behavior of scoliosis during growth in children with osteogenesis imperfecta.

BACKGROUND: Spinal deformities are common in patients with osteogenesis imperfecta, a heritable disorder that causes bone fragility. The purpose of this study was to describe the behavior of spinal curvature during growth in patients with osteogenesis imperfecta and establish its relationship to disease severity and medical treatment with bisphosphonates. METHODS: The medical records and radiographs of 316 patients with osteogenesis imperfecta were retrospectively reviewed. The severity of osteogenesis imperfecta was classified with the modified Sillence classification. Serial curve measurements were recorded throughout the follow-up period for each patient with scoliosis. Regression analysis was used to determine the effect of disease severity (Sillence type), patient age, and bisphosphonate treatment on the progression of scoliosis as measured with the Cobb method. RESULTS: Of the 316 patients with osteogenesis imperfecta, 157 had associated scoliosis, a prevalence of 50%. Scoliosis prevalence (68%) and mean progression rate (6° per year) were the highest in the group of patients with the most severe osteogenesis imperfecta (modified Sillence type III). A group with intermediate osteogenesis imperfecta severity, modified Sillence type IV, demonstrated intermediate scoliosis values (54%, 4° per year). The patient group with the mildest form of osteogenesis imperfecta, modified Sillence type I, had the lowest scoliosis prevalence (39%) and rate of progression (1° per year). Early treatment-before the patient reached the age of six years-of type-III osteogenesis imperfecta with bisphosphonate therapy decreased the curve progression rate by 3.8° per year, which was a significant decrease. Bisphosphonate treatment had no demonstrated beneficial effect on curve behavior in patients with other types of osteogenesis imperfecta or in patients of older age. CONCLUSIONS: The prevalence of scoliosis in association with osteogenesis imperfecta is high. Progression rates of scoliosis in children with osteogenesis imperfecta are variable, depending on the Sillence type of osteogenesis imperfecta. High rates of scoliosis progression in type-III and type-IV osteogenesis imperfecta contrast with a benign course in type I. Bisphosphonate therapy initiated before the patient reaches the age of six years can modulate curve progression in type-III osteogenesis imperfecta.

Effect of Lowest Instrumented Vertebra on Trunk Mobility in Patients With Adolescent Idiopathic Scoliosis Undergoing a Posterior Spinal Fusion.

STUDY DESIGN: Prospective. OBJECTIVES: The goal of this study was to evaluate the effect of posterior spinal fusion surgery terminating at different lowest instrumented vertebrae (LIV) on trunk mobility in individuals with adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Posterior spinal fusion with instrumentation is the standard surgical technique employed in AIS for correcting spine deformities with Cobb angles exceeding 50°. Surgical correction of curve deformity reduces trunk mobility and range of motion. However, conflicting findings from previous studies investigating the impact of different LIV levels on the reduction in trunk mobility after surgery have been reported. METHODS: The study was designed as a prospective study with 47 patients (7 males and 40 females) with AIS who underwent posterior spinal fusion. Patients were classified into 5 groups based on their surgical LIV level (ie, T12, L1, L2, L3, and L4). Trunk flexion-extension (sagittal plane), lateral bending (coronal plane), and axial rotation (transverse plane) kinematics were assessed during preoperative, 1 year postoperative, and 2 years postoperative evaluation visits. RESULTS: There were postoperative reductions of 41%, 51%, and 59% in trunk range of motion in the sagittal, coronal, and transverse planes, respectively (p < .0001). A trend toward greater postoperative reductions in peak forward flexion at more distal LIVs was observed (p = .04). CONCLUSIONS: Fusion reduces trunk mobility in the sagittal, coronal, and transverse planes. More distal LIV fusions limit peak forward flexion to a greater extent which is considered clinically significant. After fusion, the reductions seen in axial rotation, lateral bending, and backward extension do not differ significantly at more distal LIVs.

Convex hemiepiphysiodesis: the limits of vertebral stapling.

STUDY DESIGN: We performed a retrospective chart review of patients with nonadolescent idiopathic scoliosis who underwent open vertebral stapling for treatment of spinal deformity. OBJECTIVE: The objective of this study was to determine the efficacy of vertebral stapling in patients with scoliosis. Measurements included initial deformity correction and maintenance of correction. SUMMARY OF BACKGROUND DATA: Growth modulation has become a topic of interest recently in the spinal deformity literature. It refers to the tethering of growth on one side of the spine to allow for compensatory growth on the contralateral side, and, in theory, correction of scoliosis. Recent studies on endoscopic vertebral stapling have shown promising early results in adolescents with idiopathic scoliosis. Little is known about its applicability in patients with more "malignant" types of scoliosis. METHODS: The medical records and radiographs of 11 children who underwent open vertebral stapling between June 2003 and August 2004 were reviewed. Patients with adolescent idiopathic scoliosis (AIS) were excluded. RESULTS.: Diagnoses included myelodysplasia, congenital scoliosis, juvenile, and infantile idiopathic scoliosis, Marfan syndrome, paralytic scoliosis, and neuromuscular scoliosis. The average age at surgery was 6 + 11 year. All patients were skeletally immature. Preoperative curves averaged 68° (22°-105°). Of the 11, six thoracic curves and five thoracolumbar curves were stapled. Four patients had minor curves, which were not stapled. Initial postoperative radiographs averaged 45° (24°-88°). Average follow-up was 22 month for our series (16-28 month). At final follow-up, scoliosis averaged 69° (36°-107°). Five of the 11 patients have subsequently undergone secondary surgical procedures for progression of scoliosis, including growing rod insertion in three, combined anterior/posterior spinal fusion in another, and bilateral vertical expandable prosthetic titanium rib insertion in a patient with myelodysplasia. Three of the remaining six patients are scheduled for secondary surgery. CONCLUSION: More than half of the patients in our series have undergone or are scheduled to undergo further spinal surgery, at an average of 2 year after anterior vertebral stapling. It is unclear if progression may be related to the young age at surgery, the relatively severe average preoperative curve magnitude, the nature of the underlying scoliosis, or a combination of these.

Infection after spinal fusion for pediatric spinal deformity: thirty years of experience at a single institution.

STUDY DESIGN: A retrospective, consecutive case study of 1571 pediatric patients who underwent spinal deformity surgery and had minimum 2-year follow-up. OBJECTIVE: To identify (1) the rate of infection after pediatric spinal deformity surgery; (2) the number of surgeries required to treat a postoperative infection after a pediatric spinal deformity surgery; (3) the percentage of patients with a postoperative infection after pediatric spinal deformity surgery who require implant removal to quantify the effect of removal on the deformity; and (4) the microbiology of postoperative infections after pediatric spinal deformity surgery. SUMMARY OF BACKGROUND DATA: Several previous reports have discussed the rates of infection after spinal surgery for pediatric spinal deformity. No previous reports have quantified the rate and magnitude of deformity progression after infection in pediatric spinal deformity surgery. METHODS: A retrospective review was performed of the medical records and radiographs of all children undergoing surgery for spinal deformity at the Shriners Hospital for Children in Chicago from January 1, 1975, to June 1, 2005. RESULTS: The rate of infection varied based on underlying diagnosis: idiopathic scoliosis 0.5%, myelomeningocele 19.2%, myopathies 4.3%, and cerebral palsy 11.2%. On average, 2 surgeries were required to eradicate the infection. Approximately half of the patients required removal of the instrumentation to treat their infection. Forty-four percent of patients who developed an infection had significant progression of their deformity, with an average increase in deformity magnitude of 27 degrees. Implant removal predisposed patients to progression of deformity. The 3 most common organisms in order were Staphylococcus aureus, S. epidermidis, and Pseudomonas aeruginosa. CONCLUSION: Infection after spinal deformity in idiopathic scoliosis is rare but is relatively common in neuromuscular conditions. Eradication of infection can be expected, but implant removal is often required. Should implants be totally removed, significant progression of the deformity is possible.

New concepts on the pathogenesis and classification of spondylolisthesis.

STUDY DESIGN: A review of the literature in the English language pertaining to the pathogenesis and classification of spondylolisthesis. OBJECTIVE: To review the morphology and biomechanics of the lumbosacral junction as it relates to spondylolisthesis. To present contemporary theories of the development and progression of spondylolisthesis and an etiology-based classification system. SUMMARY OF BACKGROUND DATA: The proper treatment of spondylolisthesis is dependent on recognizing the type of slip and its natural history. Although a number of clinical and radiographic features have been identified as risk factors, their role as primary causative factors or secondary adaptive changes is not clear. In particular, confusion persists over the classification of slips with "isthmic defects." The early identification of spondylolisthesis that will progress to a high grade without intervention remains elusive. METHODS: A review of English language literature regarding the pathogenesis and classification of spondylolisthesis. RESULTS.: Current literature suggests that spinopelvic parameters, in addition to the morphology and biomechanics of the lumbosacral junction, play a causative role in the development of spondylolisthesis. Progression of developmental slips may be due to growth deficiencies of the anterosuperior sacrum, analogous to Blount's disease at the knee. The Marchetti-Bartolozzi classification system emphasizes the distinction between developmental dysplastic slips and acquired laminar stress fractures, both of which may have isthmic defects. These two types of spondylolisthesis have significantly different natural histories, suggesting the need for different treatment strategies. The Marchetti-Bartolozzi system also allows for the classification of postsurgical, pathologic, and degenerative forms of spondylolisthesis. CONCLUSIONS: The morphology of the lumbosacral junction resists high shear and compressive forces. The loss of the posterior restraint through an incompetent bony hook may result in the forward displacement of one vertebra on the subjacent vertebra. The spinopelvic parameters, such as pelvic incidence, may be greater determinants of development and progression than previously appreciated. The Marchetti-Bartolozzi classification system is applicable to all forms of lumbar spondylolisthesis,and seems to be clinically relevant in terms of treatment decisions. Their system emphasizes the distinction between developmental spondylolisthesis with lysis and acquired spondylitic spondylolisthesis, which have been included together in previous classification systems and caused confusion over natural history and treatment. Developmental slips have a greater propensity toward progression, which may be secondary to growth deficiencies of the upper sacrum. Further study is required to confirm these observations.

Evaluation and management of high-grade spondylolisthesis in adults.

STUDY DESIGN: A retrospective review was performed on 21 adult patients surgically treated with high-grade spondylolisthesis (Grade III, IV, or V). Additionally, the natural history, classification, and surgical alternatives for high-grade spondylolisthesis in the adult are discussed through literature review. OBJECTIVES: The purpose of this article is to review the clinical and radiographic outcomes of surgical treatment of high-grade spondylolisthesis in the adult from a single institution. The natural history and treatment options for these adults are described in this review. SUMMARY OF BACKGROUND DATA: High-grade spondylolisthesis is typically diagnosed and treated in the child or adolescent. Most patients with high-grade spondylolisthesis received surgical treatment during their adolescence. Some patients, however, remain minimally symptomatic for life without surgery. Little has been written on the natural history or treatment of adults with high grades of spondylolisthesis. Most of the published reports on the surgical treatment of high-grade spondylolisthesis pertain to skeletally immature patients and maybe include a few adults in their series. Nonetheless, the different techniques of surgical treatment for high-grade spondylolisthesis that have been described in these studies can help the spinal surgeon in treatment options for this rare but difficult spinal deformity. METHODS: A literature review of the published manuscripts on the treatment of high-grade spondylolisthesis was performed with particular attention to the natural history and surgical treatment involving adult patients. Adult patients (older than 21 years) with high-grade spondylolisthesis treated surgically were retrospectively reviewed. Patients' clinical charts and radiographs were reviewed before and after surgery. Determination of fusion success, clinical outcome, and complications were performed. RESULTS: Twenty-one consecutive adults with high-grade spondylolisthesis who underwent lumbar spinal surgery were review retrospectively between 1990 and 2004. There were 13 females and 8 males with an average age of 35 years (range, 21-68 years). The average follow-up was 6.6 years. There were 11 Grade III, 6 Grade IV, and 4 Grade V slips, including 4 acquired and 17 developmental spondylolistheses. There were no pseudarthroses or significant instrumentation failures. There was 1 case of a complete cauda equina syndrome on a patient with preoperative symptoms of an incomplete cauda equina syndrome. CONCLUSIONS: Adult patients with high-grade spondylolisthesis not responding to nonoperative treatment can be stabilized in situ with posterior instrumentation from L4 to S1. The use of adjunctive fixation with iliac screws and/or transvertebral screws is recommended for the adult patient, particularly in revision or unstable cases. Reduction of the slipped vertebrae remains controversial for all grades of spondylolisthesis and more so for the adult patient. Partial reduction of the slip angle, decreasing the lumbosacral kyphosis, should be considered if significant sagittal malalignment is present or to improve arthrodesis success. Anterior column support should be performed, particularly when reduction has been obtained. Anterior column support can be performed, anteriorly or posteriorly, either by using inter vertebral body structural strut support or with a transsacral fibular dowel to improve stability and success of arthrodesis.

Selective anterior fusion and instrumentation for the treatment of neuromuscular scoliosis.

STUDY DESIGN: A retrospective cohort study was conducted. OBJECTIVE: To evaluate the results of anterior spinal fusion with anterior instrumentation alone in selected patients with neuromuscular scoliosis. SUMMARY OF BACKGROUND DATA: Traditionally posterior spinal fusion with instrumentation has been done, usually to the pelvis, to achieve correction of neuromuscular scoliosis. However, certain selected patients might benefit from shorter fusion segment to preserve some motion and yet still achieve good correction of the curve. This may serve to improve or preserve various functional abilities that might be adversely affected by a long fusion. METHOD: Patients who had anterior spinal fusion (ASF) with anterior instrumentation (AI) alone were selected from an entire group of patients with neuromuscular spinal deformity who had surgery at Shriners Hospital for Children-Chicago since January of 1988. The charts and radiographs of these patients were examined and various radiographic parameters were measured pre- and after surgery and at final follow-up. Additionally, functional level of the patients included, ambulatory status was obtained from the medical records. RESULTS: In these 21 patients excellent results were obtained with regard to primary and secondary curve correction as well as the pelvic obliquity without significant deterioration at final follow-up. Ambulatory status was not changed after surgery. This cohort of patients had various neuromuscular diseases. However, the majority of them had myelomeningocele. Few complications occurred which resulted in the reoperation of several patients who had progression of the curve around the instrumented segment which itself remained unchanged when the complication was recognized. One infection occurred requiring irrigation and debridement. CONCLUSIONS: In selected patients with neuromuscular scoliosis, even that associated with pelvic obliquity, excellent correction and maintenance correction can be obtained fusing a relatively short segment of the spine with ASF and AI rather than a long construct posteriorly to the pelvis. Maintenance of the correction of the primary curve as well as the pelvic obliquity was maintained over the period of follow-up. This approach for selected patients should be offered as a way of limiting the extend of the surgery, preserving motion segments and maintaining orenhancing functions such as activities of daily living.

Long structural allografts in the treatment of anterior spinal column defects.

A retrospective study of 41 patients who had anterior spinal column reconstruction using long-segment allografts between 1983 and 1998 is reported. A long-segment allograft was defined as an allograft strut that replaces a vertebral body or approximates the height of the adjacent vertebral body for the thoracolumbar or lumbar spine, or more than two vertebral bodies for the cervical or cervicothoracic spine. Forty of the 41 patients had successful anterior strut grafting with radiographic evidence of allograft incorporation at the last followup with the majority of patients having radiographic evidence of incorporation by 6 months. There where three early complications related to the allograft (two end plate fractures and one repeated cervical spine allograft dislodgment) and one late complication associated with the posterior adjunct instrumentation unrelated to the allograft (degenerative lumbar stenosis). The only procedural complication was a deep venous thrombosis and a resultant nonfatal pulmonary embolus. No allografts fractured or collapsed. These data suggest that long-segment anterior allografts work exceptionally well in maintaining vertebral height and structural integrity in numerous pathologic deformities including traumatic and infectious etiologies.