Intraoperative neuromonitoring predicts postoperative deficits in severe pediatric spinal deformity patients.

PURPOSE: To evaluate intraoperative monitoring (IOM) alerts and neurologic deficits during severe pediatric spinal deformity surgery. METHODS: Patients with a minimum Cobb angle of 100° in any plane or a scheduled vertebral column resection (VCR) with minimum 2-year follow-up were prospectively evaluated (n = 243). Preoperative, immediate postoperative, and 2-year postoperative neurologic status were reported. Radiographic data included preoperative and 2-year postoperative coronal and sagittal Cobb angles and deformity angular ratios (DAR). IOM alert type and triggering event were recorded. SRS-22r scores were collected preoperatively and 2-years postoperatively. RESULTS: IOM alerts occurred in 37% of procedures with three-column osteotomy (n = 36) and correction maneuver (n = 32) as most common triggering events. Patients with IOM alerts had greater maximum kyphosis (101.4° vs. 87.5°) and sagittal DAR (16.8 vs. 12.7) (p < 0.01). Multivariate regression demonstrated that sagittal DAR independently predicted IOM alerts (OR 1.05, 95% CI 1.02-1.08) with moderate sensitivity (60.2%) and specificity (64.8%) using a threshold value of 14.3 (p < 0.01). IOM alerts occurred more frequently in procedures with new postoperative neurologic deficits (17/24), and alerts with both SSEP and TCeMEP signals were associated with new postoperative deficits (p < 0.01). Most patients with new deficits experienced resolution at 2 years (16/20) and had equivalent postoperative SRS-22r scores. However, patients with persistent deficits had worse SRS-22r total score (3.8 vs. 4.2), self-image subscore (3.5 vs. 4.1), and function subscore (3.8 vs. 4.3) (p ≤ 0.04). CONCLUSION: Multimodal IOM alerts are associated with sagittal kyphosis, and predict postoperative neurologic deficits. Most patients with new deficits experience resolution of their symptoms and have equivalent 2-year outcomes. LEVEL OF EVIDENCE: II.

Perioperative Complications and Health-related Quality of Life Outcomes in Severe Pediatric Spinal Deformity.

STUDY DESIGN: Prospective multicenter cohort study. OBJECTIVE: To evaluate perioperative complications and mid-term outcomes for severe pediatric spinal deformity. SUMMARY OF BACKGROUND DATA: Few studies have evaluated the impact of complications on health-related quality of life (HRQoL) outcomes in severe pediatric spinal deformity. METHODS: Patients from a prospective, multicenter database with severe pediatric spinal deformity (minimum of 100 degree curve in any plane or planned vertebral column resection (VCR)) with a minimum of 2-years follow-up were evaluated (n=231). SRS-22r scores were collected preoperatively and at 2-years postoperatively. Complications were categorized as intraoperative, early postoperative (within 90-days of surgery), major, or minor. Perioperative complication rate was evaluated between patients with and without VCR. Additionally, SRS-22r scores were compared between patients with and without complications. RESULTS: Perioperative complications occurred in 135 (58%) patients, and major complications occurred in 53 (23%) patients. Patients that underwent VCR had a higher incidence of early postoperative complications than patients without VCR (28.9% vs. 16.2%, P =0.02). Complications resolved in 126/135 (93.3%) patients with a mean time to resolution of 91.63 days. Unresolved major complications included motor deficit (n=4), spinal cord deficit (n=1), nerve root deficit (n=1), compartment syndrome (n=1), and motor weakness due to recurrent intradural tumor (n=1). Patients with complications, major complications, or multiple complications had equivalent postoperative SRS-22r scores. Patients with motor deficits had lower postoperative satisfaction subscore (4.32 vs. 4.51, P =0.03), but patients with resolved motor deficits had equivalent postoperative scores in all domains. Patients with unresolved complications had lower postoperative satisfaction subscore (3.94 vs. 4.47, P =0.03) and less postoperative improvement in self-image subscore (0.64 vs. 1.42, P =0.03) as compared to patients with resolved complications. CONCLUSION: Most perioperative complications for severe pediatric spinal deformity resolve within 2-years postoperatively and do not result in adverse HRQoL outcomes. However, patients with unresolved complications have decreased HRQoL outcomes.

Late Infection After Spinal Fusion for Adolescent Idiopathic Scoliosis: Implant Exchange Versus Removal.

BACKGROUND: Late infection after posterior spinal arthrodesis for adolescent idiopathic scoliosis (AIS) is the leading cause of late revision. While implant removal and antibiotic therapy are usually curative, patients may experience deformity progression. The goal of this study was to compare outcomes after implant exchange (IE) or removal (IR) to treat late-onset (≥1 y postoperative) deep surgical site infection (SSI) after spinal arthrodesis in patients with AIS. METHODS: Using a multicenter AIS registry, patients who underwent posterior spinal fusion between 2005 and 2019 and developed late deep SSI treated with IE or IR were identified. Radiographic, surgical, clinical, and patient-reported outcomes at most recent follow-up were compared. RESULTS: Of 3,705 patients, 47 (1.3%) developed late infection 3.8±2.2 years (range 1 to 9.7 y) after index surgery. Mean follow-up after index surgery was 6.1 years, with 2.8 years (range 25 to 120 mo) of follow-up after revision surgery. Twenty-one patients were treated with IE and 26 with IR. At the latest follow-up, average major-curve loss of correction (1° vs 9°, P <0.001) and increase in kyphosis (1° vs. 8°, P =0.04) were smaller in the IE group than in the IR group. Two IR patients but no IE patients had reoperation. Patients who underwent IE had higher Scoliosis Research Society 22-Item Patient Questionnaire (SRS-22) total scores (4.38 vs. 3.81, P =0.02) as well as better subscores for self-image, function, and satisfaction at the latest follow-up than those who underwent IR only. There were no significant between-group differences in operative duration, estimated blood loss, length of hospital stay, or changes in SRS-22 total scores. No patient had a subsequent infection during the follow-up period. CONCLUSIONS: When treating late-onset deep SSI after posterior spinal fusion for AIS, single-stage IE is associated with better maintenance of major curve correction, sagittal profile, and patient-reported outcomes and fewer reoperations compared with IR, with no significant differences in blood loss, operative duration, or length of stay. No time interval from index surgery to IR was observed where the corrected deformity remained stable. Both techniques were curative of infection. LEVEL OF EVIDENCE: Level III.

Late spinal infections following posterior spinal fusion in pediatric deformities: treatment using single-stage titanium implant exchange.

PURPOSE: Late infection following posterior spinal fusion (PSF) for deformity is a leading cause of revision. The purpose of this study is to evaluate clinical and radiographic outcomes following a single-stage debridement and exchange of spinal implants with titanium in adolescent patients with late-onset infections following PSF METHODS: A retrospective review of prospectively collected data of adolescent patients with spinal deformity, who were surgically treated with PSF was collected. Patients were included for the study if they developed late arising infection (> 1 year after index posterior fusion for the deformity) from 2006-2019. Treatment consisted of irrigation, debridement, implant exchange with titanium screws and rods, and antibiotics. Parameters evaluated include radiographic Cobb angles, operative data, and clinical data, all at minimum 2-year follow-up. RESULTS: 31 patients (29 with AIS and 2 with Scheuermann's kyphosis) developed late spinal infections. Mean age was 11.4 ± 2.3 years, 84% female, mean time from index surgery was 52.5 months. 25 had all stainless steel implants and 6 had cobalt chrome during the index procedure. Positive cultures were obtained in 5 patients (2 Staphylococcus Aureus, 1 Staphylococcus epidermidis, 1 Peptostreptococcus, 1 Pseudomonas aeruginosa) with cultures followed till 7 days post-operatively. At 2-years following the exchange, there was no change in coronal and sagittal alignment. Three (9%) patients developed subsequent infection necessitating implant removal. CONCLUSION: A single-stage procedure consisting of implant removal, irrigation, and debridement, and replacement with all titanium implants is an effective treatment strategy in patients developing late wound infection following PSF with regards to maintenance of curve correction and minimizing recurrent infections.

Restoration of Thoracic Kyphosis in Adolescent Idiopathic Scoliosis Over a Twenty-year Period: Are We Getting Better?

STUDY DESIGN: A multicenter, prospectively collected database of 20 years of operatively treated adolescent idiopathic scoliosis (AIS) was utilized to retrospectively examine pre- and postoperative thoracic kyphosis at 2-year follow-up. OBJECTIVE: To determine if the adoption of advanced three-dimensional correction techniques has led to improved thoracic kyphosis correction in AIS. SUMMARY OF BACKGROUND DATA: Over the past 20 years, there has been an evolution of operative treatment for AIS, with more emphasis on sagittal and axial planes. Thoracic hypokyphosis was well treated with an anterior approach, but this was not addressed sufficiently in early posterior approaches. We hypothesized that patients with preoperative thoracic hypokyphosis prior to 2000 would have superior thoracic kyphosis restoration, but the learning curve with pedicle screws would reflect initially inferior restoration and eventual improvement. METHODS: From 1995 to 2015, 1063 patients with preoperative thoracic hypokyphosis (<10°) were identified. A validated formula for assessing three-dimensional sagittal alignment using two-dimensional kyphosis and thoracic Cobb angle was applied. Patients were divided into 1995-2000 (Period 1, primarily anterior), 2001-2009 (Period 2, early thoracic pedicle screws), and 2010-2015 (Period 3, modern posterior) cohorts. Two-way repeated measures analysis of variance and post-hoc Bonferroni corrections were utilized with P < 0.05 considered significant. RESULTS: Significant differences were demonstrated. Period 1 had excellent restoration of thoracic kyphosis, which worsened in Period 2 and improved to near Period 1 levels during Period 3. Period 3 had superior thoracic kyphosis restoration compared with Period 2. CONCLUSION: Although the shift from anterior to posterior approaches in AIS was initially associated with worse thoracic kyphosis restoration, this improved with time. The proportion of patients restored to >20° kyphosis with a contemporary posterior approach has steadily improved to that of the era when anterior approaches were more common. LEVEL OF EVIDENCE: 3.

Delayed quadriparesis after posterior spinal fusion for scoliosis: a case series.

STUDY DESIGN: A multicenter retrospective IRB exempt case series analyzing clinical and radiographical data of patients treated by three surgeons over the past two decades was conducted. OBJECTIVE: To examine the factors involved in the development of quadriparesis in patients who underwent posterior spinal fusion for scoliosis. Delayed spinal cord infarcts usually present at the region of instrumentation according to reports from the Scoliosis Research Society. Nonetheless, there is a lack of data regarding factors associated with delayed quadriparesis following posterior spinal fusion METHODS: Evaluated variables were age, Cobb angle, blood loss, and curve correction percentage. Postoperative imaging was also evaluated to determine factors indicative of the etiology of the quadriparesis. RESULTS: Eight patients presented delayed postoperative quadriparesis. All patients had a postoperative examination equal to that of baseline. The first patient deteriorated at 6 h postoperatively and the most delayed patient presented 4 days postoperatively. Six patients had neuromuscular disorders and 2 had adolescent idiopathic scoliosis. Mean age was 13.7, mean curve magnitude was 78.7°, mean percent curve correction was 71% and the mean estimated blood loss was 1185 cc. Seven of eight patients had documented peri- or postoperative hypotension. CONCLUSIONS: Cervical infarction is the likely cause of delayed quadriparesis after posterior spinal fusion. Even though the underlying etiology continues to be unclear, postoperative hypotension, curve magnitude, percent curve correction, and the presence of cervical kyphosis/stenosis may be contributory and need to be closely evaluated. LEVEL OF EVIDENCE: IV, Case Series.

Ponte Osteotomies Increase the Risk of Neuromonitoring Alerts in Adolescent Idiopathic Scoliosis Correction Surgery.

STUDY DESIGN: Observational cohort study of prospective database registry. OBJECTIVE: To determine the incidence of neurological complications in AIS patients undergoing surgical treatment with PO. SUMMARY OF BACKGROUND DATA: Despite the widespread use of Ponte Osteotomies (PO) in adolescent idiopathic scoliosis (AIS) correction, outcomes and complications in patients treated with this technique have not been well characterized. METHODS: A multicenter prospective registry of patients undergoing surgical correction of AIS was queried at 2-year follow-up for patient demographics, surgical data, deformity characteristics, and peri-operative complications. A neurological complication was defined as perioperative nerve root or spinal cord injury as identified by the surgeon. Patients were divided into those who underwent peri-apical PO and those without, and further stratified by Lenke curve classification into 3 groups (I-types 1 and 2, II-types 3, 4, 6, and III-type 5). Patients with- and without neurological complications were compared with respect to baseline demographics, surgical variables, curve types, fusion construct types (screws vs. hybrid), curve magnitude (coronal and sagittal Cobb), apical vertebral translation, and coronal-deformity angular ratios (C-DAR). RESULTS: Of 2210 patients included in the study, 1611 underwent PO. Peri-operative neurological complications occurred in 7 patients, with 6 in the PO group (0.37%) and 1 in non-PO group (0.17%) though this was not a statistically significant risk factor for peri-operative neurological injury (P = 0.45). Neuromonitoring alerts were recorded in 168 patients (7.6%: 9.3% PO group; 4.2% no-PO group (P < 0.001)). Multivariate logistic regression analysis found PO and curve magnitude to be independent risk factors for intraoperative neuromonitoring alerts (P < 0.01). CONCLUSION: PO and curve magnitude were independent risk factors for intraoperative neuromonitoring alerts in surgical AIS correction. The effect of Ponte osteotomy on neurological complications remains unknown due to the low incidence of these complications. LEVEL OF EVIDENCE: 3.

Disc Degeneration in Unfused Caudal Motion Segments Ten Years Following Surgery for Adolescent Idiopathic Scoliosis.

HYPOTHESIS: The frequency of disc degeneration (DD) in the distal mobile segments will increase over time following surgery for adolescent idiopathic scoliosis (AIS). DESIGN: Retrospective review of a prospective AIS registry. INTRODUCTION: Durability of surgical outcomes is essential for maintenance of quality of life as well as for family decision making and for assessment of the value of a healthcare intervention. We assessed DD, its risk factors, and association with health-related quality of life 10 years after AIS surgery. METHODS: Five radiographic indicators of DD, previously validated, were evaluated preoperatively and 1 month, 2, 5, and 10 years postoperatively by a radiologist in operative AIS patients. A composite radiographic score (CRS; range 0-10) was calculated using the sum of each of the DD indicators. The severity of CRS in relation to the time point after surgery and various risk factors were assessed using linear regression or Pearson χ2 test. CRS ≥3 was chosen to indicate significant DD. Association of CRS with SRS-22 outcome was evaluated by linear regression. RESULTS: 193 consecutive patients (mean age at surgery 14.4 years; 86% female) were assessed. Surgical approach included 102 posterior and 91 anterior fusions. Contributors to maximum CRS at 10 years were Schmorl's nodes (7.3% of patients), osteophytes (40.4%), sclerosis (29%), and irregular endplate (8.3%). CRS ≥3 occurred in 1.6%, 0.54%, 3.7%, 6.8%, and 7.3% of patients at the various time points (r2=0.83, p=.0313), respectively. More than 50% of DD occurred at the second (35.5%) and third (20%) disc caudal to the LIV. LIV of L4 compared with more cephalad LIV had the highest risk of developing significant DD (27.3%; p=.0267). It was found that disc wedging subjacent to the LIV (≥5°) and LIV translation (≥2 cm) lead to a sixfold increase in significant DD (odds ratio=6.71 and 6.13, respectively). Severity of DD was not associated with the number of levels fused (p=.2131), the surgical approach (p=.8245), or the construct type (p=.2922). No significant association was established between 10-year CRS and SRS-22 scores. CONCLUSION: In the first study of its kind, we found that only 7.3% of patients had significant DD 10 years after surgical correction of AIS. Rates of DD increased over time. Our data provide evidence to support recommendations to save as many caudal motion segments as possible, to avoid fusing to L4, and maintain the LIV tilt angle below 5° and LIV translation less than 2 cm.

Reciprocal Changes in Sagittal Alignment With Operative Treatment of Adolescent Scheuermann Kyphosis-Prospective Evaluation of 96 Patients.

INTRODUCTION: Sagittal alignment abnormalities in Scheuermann kyphosis (SK) strongly correlate with quality of life measures. The changes in spinopelvic parameters after posterior spinal fusion have not been adequately studied. This study is to evaluate the reciprocal changes in spinopelvic parameters following surgical correction for SK. METHODS: Ninety-six operative SK patients (65% male; age 16 years) with minimum 2-year follow-up were identified in the prospective multicenter study. Changes in spinopelvic parameters and the incidence of proximal (PJK) and distal (DJK) junctional kyphosis were assessed as were changes in Scoliosis Research Society-22 (SRS-22) questionnaire scores. RESULTS: Maximum kyphosis improved from 74.4° to 46.1° (p < .0001), and lumbar lordosis was reduced by 10° (-63.3° to -53.3°; p < .0001) at 2-year postoperation. Pelvic tilt, sacral slope, and sagittal vertical axis remained unchanged. PJK and DJK incidence were 24.2% and 0%, respectively. In patients with PI <45°, patients who developed PJK had greater postoperative T2-T12 (54.8° vs. 44.2°, p = .0019), and postoperative maximum kyphosis (56.4° vs. 44.6°, p = .0005) than those without PJK. In patients with PI ≥45°, patients with PJK had less postoperative T5-T12 than those without (23.6° vs. 32.9°, p = .019). Thoracic and lumbar apices migrated closer to the gravity line after surgery (-10.06 to -4.87 mm, p < .0001, and 2.28 to 2.10 mm, p = .001, respectively). Apex location was normalized to between T5-T8 in 68.5% of patients with a preoperative apex caudal to T8, whereas 90% of patients with a preoperative apex between T5 and T8 remained unchanged. Changes in thoracic apex location and lumbar apex translation were associated with improvements in the SRS function domain. CONCLUSION: PJK occurred in 1 in 4 patients, a lower incidence than previously reported perhaps because of improved techniques and planning. Both thoracic and lumbar apices migrated closer to the gravity line, and preoperative apices caudal to T8 normalized in more than two-thirds of patients, resulting in improved postoperative function. Individualizing kyphosis correction to prevent kyphosis and PI mismatch may be protective against PJK.

A Detailed Comparative Analysis of Anterior Versus Posterior Approach to Lenke 5C Curves.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To prospectively compare radiographic, perioperative, and functional outcomes between anterior spinal instrumentation and fusion (ASIF) and posterior spinal instrumentation and fusion (PSIF) in Lenke 5C curves. SUMMARY OF BACKGROUND DATA: Historically, ASIF has been the treatment of choice for treatment of thoracolumbar adolescent idiopathic scoliosis. More recently, PSIF has gained popularity for its ease, versatility, and amount of correction achieved. Current literature lacks a prospective comparative analysis between these two approaches to better aid treating surgeons in decision making when treating Lenke 5C curves. METHODS: A prospective, longitudinal multicenter adolescent idiopathic scoliosis database was used to identify 161 consecutive patients with Lenke 5C curves treated by ASIF with a dual rod system, or PSIF with a pedicle screw-rod construct. Pre- and 2-year postoperative radiographic data, Scoliosis Research Society outcome scores, and perioperative comparisons were made between the two approaches. RESULTS: A total of 69 patients were treated with ASIF and 92 patients with PSIF. Curve extent, magnitude, stable, and end vertebrae distribution before surgery were similar between the two groups. At 2-year follow-up, there were no significant differences in percentage correction of the main curve (ASIF: 59.1%, PSIF: 59.6%), C7 decompensation (ASIF: -0.6 ±â€Š1.2, PSIF: -0.3 ±â€Š1.4 cm), length of hospital stay (ASIF: 5.6 days, PSIF: 5.7 days), postoperative day conversion to oral pain medication (ASIF: 3.2 days, PSIF: 3.2 days), and SRS outcome scores (P = 0.560) between the two groups. The number of levels fused was significantly lower in ASIF group (ASIF: 4.7, PSIF: 6.3; P < 0.001), but PSIF resulted in significantly less disc angulation below lowest instrumented vertebrae (ASIF: 3.4°, PSIF: 1.7°; P = 0.011), greater lumbar lordosis (P < 0.001), and greater % correction of lumbar prominence (P = 0.017). CONCLUSION: The amount of correction achieved was similar between ASIF and PSIF. ASIF resulted in shorter fusions (average 1.6 levels) compared with PSIF. This was at the expense of increased disc angulation below the lowest instrumented vertebrae, less lumbar lordosis, and a lower % correction of the lumbar prominence than PSIF. LEVEL OF EVIDENCE: 2.

Evolution of Surgery for Adolescent Idiopathic Scoliosis Over 20 Years: Have Outcomes Improved?

STUDY DESIGN: Retrospective review of a prospective adolescent idiopathic scoliosis (AIS) registry. OBJECTIVE: To study the evolution of the operative approach, outcomes, and complication rates in AIS surgery over the past 20 years. SUMMARY OF BACKGROUND DATA: Surgical techniques in AIS surgery have evolved considerably over the past 20 years. We study the trends in the operative management of AIS over this period and their impact on perioperative outcomes. METHODS: A total of 1819 AIS patients (1995-2013) with 2-year F/U were studied. Operative approach, perioperative parameters, major complication rates, and SRS outcomes were assessed. Linear regression was used to assess the trend of changes over 5-year quartiles. RESULTS: Mean age at surgery was 14.6 ±â€Š2.1 years, 80.2% were females, and this remained consistent throughout. Operative time, EBL/level, and LOS decreased over the 20 years (P < 0.0001). The use of antifibrinolytic (AF) increased from 6.7% to 68.8% in the past 10 years (P < 0.0001). Number of levels fused increased and LIV was more distal (in relation to stable vertebrae) over time in Lenke 1 and 2 curves (levels fused 7.97-9.94, P < 0.0001 and 9.8-11.0, P=0.0134, respectively). Anterior spinal fusion (ASF) in Lenke 1 curves decreased from 81% in the first quartile to 0% in the last (P = 0.0429). ASF for Lenke 5 curves evolved from 78% in the second quartile to 0 in the last. Thoracoplasty performance decreased from 76% to 20.3% (P = 0.1632). All screw constructs in PSF cases increased from 0% to 98.4% (P = 0.0095). Two-year major complication rates decreased over time (18.7%-5.1%; P = 0.0173). Increased improvement in SRS scores were observed in pain, image, function, and total domains. CONCLUSION: Evolution of surgical technique in AIS over the past 20 years has resulted in a cessation of anterior only surgery, increasing use of all screw constructs, less blood loss, greater use of AF, shorter operative times and LOS, lower major complications rates, and greater improvements in SRS scores. LEVEL OF EVIDENCE: 2.

Resource Utilization in Adolescent Idiopathic Scoliosis Surgery: Is There Opportunity for Standardization?

INTRODUCTION: Recent healthcare reforms have raised the importance of cost and value in the management of disease. Value is a function of benefit and cost. Understanding variability in resources utilized by individual surgeons to achieve similar outcomes may provide an opportunity for cutting costs though greater standardization. The purpose of this study is to evaluate differences in use of implants and hospital resources among surgeons performing adolescent idiopathic scoliosis (AIS) surgery. METHODS: A multicenter prospective AIS operative database was queried. Patients were matched for Lenke curve type and curve magnitude, resulting in 5 surgeons and 35 matched groups (N = 175). Mean patient age was 14.9 years and curve magnitude 50°. Parameters of interest were compared between surgeons via ANOVA and Bonferroni pairwise comparison. RESULTS: There was no significant difference in percentage curve correction or levels fused between surgeons. Significant differences between surgeons were found for percentage posterior approach, operative time, length of stay (LOS), estimated blood loss (EBL), cell saver transfused, rod material, screw density, number of screws, use of antifibrinolytics, and cessation of intravenous analgesics. Despite differences in EBL and cell saver transfused, there were no differences in allogenic blood (blood bank) use. CONCLUSION: Significant variability in resource utilization was noted between surgeons performing AIS operations, although radiographic results were uniform. Standardization of resource utilization and cost containment opportunities include implant usage, rod material, LOS, and transition to oral analgesics, as these factors are the largest contributors to cost in AIS surgery.

Risk Factors of Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis-The Pelvis and Other Considerations.

STUDY DESIGN: Prospective multicenter database study. OBJECTIVES: To assess the incidence of proximal junctional kyphosis (PJK) in operative adolescent idiopathic scoliosis (AIS) using contemporary surgical techniques and to identify risk factors for PJK. SUMMARY OF BACKGROUND DATA: The incidence of PJK has been reported as high as 46% in AIS. Factors associated with PJK have been incompletely explored. METHODS: Prospectively enrolled 851 AIS patients (2000-2011, 78.5% female, average 14.4 years) were evaluated 2 years postoperatively. Radiographic and sagittal spinopelvic parameters and rod contour angle (RCA), a new measure that reflects the proximal contouring of the rod, were independently evaluated for association with PJK based on Lenke type. Multivariate logistic regression with backward elimination was performed to identify risk factors for PJK. RESULTS: Overall PJK incidence was 7.05% and varies based on Lenke type (Lenke 1, 6.35%; Lenke 2 and 4, 4.39%; Lenke 3 and 6, 11.64%; and Lenke 5, 8.49%; p = .06). Among patients with Lenke 1 curves, risk factors for PJK were loss of kyphosis after surgery, and stopping caudal to the upper end vertebra (UEV). The risk of developing PJK increases by 7.1% with each lost degree of kyphosis compared with preoperation that occurs after the instrumentation is placed. For Lenke 2 and 4 curves, loss of kyphosis and more lordotic (negative) RCA were risk factors for PJK. For Lenke 3 and 6 curves, larger preoperative T5-T12 kyphosis was the only significant risk factor for PJK. Upper instrumented vertebra (UIV) at or cephalad to the UEV was associated with increased risk of PJK in Lenke 5 curves, which was contrary to the finding for Lenke 1 curves. No significant correlation was found between sagittal pelvic parameters and developing PJK. CONCLUSION: The incidence of PJK in patients after surgery for AIS is 7.05% and varies based on Lenke type. Loss of kyphosis, larger preoperative kyphosis, UIV caudal to the proximal UEV (Lenke 1), UIV at or cephalad to the UEV (Lenke 5), and decreased RCA were the major risk factors for PJK in AIS. LEVEL OF EVIDENCE: Level II.

MRI Screening in Operative Scheuermann Kyphosis: Is it Necessary?

STUDY DESIGN: Patients with preoperative spine magnetic resonance imaging (MRI) studies from a prospective multicenter study of operative adolescent Scheuermann kyphosis (SK). OBJECTIVES: To investigate the usefulness of MRI screening in operative planning for SK surgeries. SUMMARY OF BACKGROUND DATA: Neural axis abnormalities in operative SK have not been previously studied with MRI screening, despite its use. METHODS: One orthopedic surgeon and two radiologists evaluated all images retrospectively. Radiographs were evaluated for kyphosis apex and magnitude. MRIs were evaluated for spinal cord abnormalities, epidural lipomatosis, location and number of vertebral wedging, Schmorl nodes and posterior disc herniations, frequency of spondylolysis, etc. The relationship of these pathologies to the kyphosis apex was explored. This group was compared to a surgical SK group without preoperative MRIs. RESULTS: Eighty-six patients with MRIs, mean age 16.3 years, 64% male, and a mean preoperative kyphosis of 75.9° were evaluated. There were 17 spinal cord abnormalities. Low-lying conus was found in 2 patients, and syrinx in 15 (no Chiari malformations). Epidural lipomatosis was found in 49 patients, average of 5.7 levels. Anterior vertebral wedging occurred in all (mean 4.7 levels). Posterior disc herniations averaged 5.2 levels/patient and 1.8 levels caudad to the apex. Spondylolysis was reported in 8.1%. Four cases (4.7%) had the operative plan changed as a result of the preoperative MRI: two due to neural compression, one due to disc herniation and one due to a spinal cord draped over the apex. Thirty-one patients did not receive an MRI; there were no significant differences between the two groups. The rate of postoperative neurologic change was 3.5% in the MRI group and 3.2% in the no-MRI group. CONCLUSIONS: Based on 4.7% of cases requiring a change in the operative plan as a result of preoperative MRI, the authors recommend considering performing screening MRI in operative SK patients.

Factors affecting the outcome in appearance of AIS surgery in terms of the minimal clinically important difference.

PURPOSE: The minimal clinically important difference (MCID) of the Appearance domain of the SRS-22 questionnaire is an increase ≥1.0 in surgically treated patients with adolescent idiopathic scoliosis (AIS). However, no study has sought to identify the factors associated with an SRS-22 Appearance score increase greater than the MCID at 2 years. METHODS: A retrospective analysis was performed on a prospectively collected multicenter database of 1020 surgically treated AIS patients with a minimum 2-year follow-up. Patients were divided into two cohorts: "I" = Improved after surgery (Δ Appearance ≥1.0) and "NI" = Not improved after surgery (Δ Appearance <1.0). Univariate regression was used to find a significant difference between the cohorts for individual measures. Multivariate logistic regression was used to find continuous predictors. RESULTS: 663 (65%) patients were improved greater than the MCID, and 357 were not improved (35%). The improved cohort trended toward a greater percentage of underweight patients (p = 0.074) with lower preoperative SRS Appearance scores (p < 0.001) and larger preoperative trunk shifts (p = 0.033). Postoperatively, those patients with greater percent correction of thoracic (p = 0.021) and lumbar (p = 0.003) Cobb angles, smaller apical lumbar translation (p = 0.006), and a greater correction in trunk shift (p = 0.003) were most likely to attain the MCID. CONCLUSION: Several factors influence which patients are most likely to attain the MCID following surgery for AIS. Factors such as preoperative appearance scores and body weight are patient specific; other factors such as percent correction of the thoracic and lumbar Cobb angles, trunk shift, and lumbar apical translation may be influenced by the surgeon. LEVEL OF EVIDENCE: II.

Posterior convex release and interbody fusion for thoracic scoliosis: technical note.

Anterior release and fusion is sometimes required in pediatric patients with thoracic scoliosis. Typically, a formal anterior approach is performed through open thoracotomy or video-assisted thoracoscopic surgery. The authors recently developed a technique for anterior release and fusion in thoracic scoliosis referred to as "posterior convex release and interbody fusion" (PCRIF). This technique is performed via the posterior-only approach typically used for posterior instrumentation and fusion and thus avoids a formal anterior approach. In this article the authors describe the technique and its use in 9 patients-to prevent a crankshaft phenomenon in 3 patients and to optimize the correction in 6 patients with a severe thoracic curve showing poor reducibility. After Ponte osteotomies at the levels requiring anterior release and fusion, intervertebral discs are approached from the convex side of the scoliosis. The annulus on the convex side of the scoliosis is incised from the lateral border of the pedicle to the lateral annulus while visualizing and protecting the pleura and spinal cord. The annulus in contact with the pleura and the anterior longitudinal ligament are removed before completing the discectomies and preparing the endplates. The PCRIF was performed at 3 levels in 4 patients and at 4 levels in 5 patients. Mean correction of the main thoracic curve, blood loss, and length of stay were 74.9%, 1290 ml, and 7.6 days, respectively. No neurological deficit, implant failure, or pseudarthrosis was observed at the last follow-up. Two patients had pleural effusion postoperatively, with 1 of them requiring placement of a chest tube. One patient had pulmonary edema secondary to fluid overload, while another patient underwent reoperation for a deep wound infection 3 weeks after the initial surgery. The technique is primarily indicated in skeletally immature patients with open triradiate cartilage and/or severe scoliosis. It can be particularly useful if there is significant vertebral rotation because access to the disc and anterior longitudinal ligament from the convex side will become safer. The PCRIF is an alternative to the formal anterior approach and does not require repositioning between the anterior and posterior stages, which prolongs the surgery and can be associated with an increased complication rate. The procedure can be done in the presence of preexisting pulmonary morbidity such as pleural adhesions and decreased pulmonary function because it does not require mobilization of the lung or single-lung ventilation. However, PCRIF can still be associated with pulmonary complications such as a pleural effusion, and care should be taken to avoid iatrogenic injury to the pleura. Placement of a deep wound drain at the level of the PCRIF is strongly recommended if postoperative bleeding is anticipated, to decrease the risk of pleural effusion.

Are S1 Screws a Useful Adjunct to Iliac Screws in Long Fusions to the Sacrum in Cerebral Palsy?

STUDY DESIGN: Multicenter prospective database review of patients with cerebral palsy (CP) and spinal deformity. OBJECTIVE: To determine if the type of distal fixation is associated with improved correction of coronal deformity or pelvic obliquity (PO) at 2 years in long posterior fusions to the sacrum. SUMMARY OF BACKGROUND DATA: Multiple techniques are utilized for distal fixation in patients with CP. Although there is emerging evidence that the augmentation of iliac screws with S1 screws may be beneficial, this remains controversial. METHODS: A prospective, multicenter database was used to identify patients with CP who underwent long posterior fusions to the sacrum. Eighty-eight patients were included, 52 with iliac screws (I) and 36 with iliac and S1 screws (IS) for distal fixation. Preoperative, first erect, and 2-year follow-up radiographs and complications were analyzed. Statistical analysis was performed using ANOVA and repeated measures ANOVA with significance set at P < 0.05. RESULTS: Scoliosis was the primary deformity in greater than 90% of patients in both groups (P=0.84). Preoperative coronal deformity was similar (I = 83°, IS = 87°, P = 0.49), but correction was better with the use of S1 screws on the first erect radiograph and at 2 years (I = 35°, IS = 22°, P = 0.001), reflecting correction of 58% and 74% for iliac and iliac-S1 screws, respectively (P < 0.001). Preoperative PO was similar (I = 29°, IS = 30°, P = 0.71) and was noted to improve more in the iliac-S1 group by 2 years (I = 11°, IS = 5°, P = 0.004), representing correction of 60% and 77% for the iliac and iliac-S1 groups, respectively (P = 0.018). There was no difference in the rate of major (P = 0.27) or minor (P = 0.65) complications in either group. CONCLUSION: Bilateral S1 and iliac screws are associated with improved spinal deformity and PO correction at 2 years in the CP population. Two points of distal fixation, S1, and ilium should be considered for this population. LEVEL OF EVIDENCE: 3.

Sagittal Spinopelvic Parameters in Scheuermann's Kyphosis: A Preliminary Study.

STUDY DESIGN: Retrospective, controlled, clinical study. OBJECTIVES: To define the average values for sagittal spinopelvic parameters including pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) in Scheuermann's kyphosis (SK); evaluate the differences in spinopelvic parameters among patients with SK and unaffected normal controls; and evaluate the correlation of various sagittal spinopelvic parameters to each other in SK and normal controls. METHODS: Prospectively collected radiographic data from a study on SK were compared with those from previously published series of unaffected patients. Measures were made according to standard, defined measurement methods. Parameters measured included PT, PI, SS, thoracic kyphosis, lumbar lordosis, and radiographic sagittal alignment. Values were compared using independent-samples t test. Pearson correlation coefficient was used to analyze relationships between variables. RESULTS: A total of 47 patients with SK and 50 control patients, mean age 16.1 and 13.5 years, respectively, were included. In SK, average PI was 42°, average PT was 7°, and average SS was 35°. These values were not different from those of normal controls (PI, 46° [p = .084]; PT, 8° [p = .476]; SS, 37° [p = .162]). Pelvic incidence directly correlated with lordosis in both groups (p < .005). T5-12 kyphosis correlated with lordosis in normal controls (p ≤ .05) but not in the SK group. Kyphosis in SK as quantified by greatest measurable Cobb angle did not correlate with PI or lordosis. CONCLUSIONS: Sagittal pelvic alignment in patients with SK is not different from that in normal subjects. Furthermore, in SK thoracic kyphosis did not correlate with any distal region of the spine (lumbar or pelvic). Further understanding of the relationship between sagittal spinopelvic alignment in various conditions causing spinal deformity will lead to better treatment of these conditions.