Adolescent Idiopathic Scoliosis Treated by Posterior Spinal Segmental Instrumented Fusion : When Is Fusion to L3 Stable?

OBJECTIVE: The purpose of this study was to identify risk factors for distal adding on (AO) or distal junctional kyphosis (DJK) in adolescent idiopathic scoliosis (AIS) treated by posterior spinal fusion (PSF) to L3 with a minimum 2-year follow-up. METHODS: AIS patients undergoing PSF to L3 by two senior surgeons from 2000-2010 were analyzed. Distal AO and DJK were deemed poor radiographic results and defined as >3 cm of deviation from L3 to the center sacral vertical line (CSVL), or >10° angle at L3-4 on the posterior anterior- or lateral X-ray at ultimate follow-up. New stable vertebra (SV) and neutral vertebra (NV) scores were defined for this study. The total stability (TS) score was the sum of the SV and NV scores. RESULTS: Ten of 76 patients (13.1%) were included in the poor radiographic outcome group. The other 66 patients were included in the good radiographic outcome group. Lower Risser grade, more SV-3 (CSVL doesn't touch the lowest instrumented vertebra [LIV]) on standing and side bending films, lesser NV and TS score, rigid L3-4 disc, more rotation and deviation of L3 were identified risk factors for AO or DJK. Age, number of fused vertebrae, curve correction, preoperative coronal/sagittal L3-4 disc angle did not differ significantly between the two groups. Multiple logistic regression results indicated that preoperative Risser grade 0, 1 (odds ratio [OR], 1.8), SV-3 at L3 in standing and side benders (OR, 2.1 and 2.8, respectively), TS score -5, -6 at L3 (OR, 4.4), rigid disc at L3-4 (OR, 3.1), LIV rotation >15° (OR, 2.9), and LIV deviation >2 cm from CSVL (OR, 2.2) were independent predictive factors. Although there was significant improvement of the of Scoliosis Research Society-22 average scores only in the good radiographic outcome group, there was no significant difference in the scores between the groups. CONCLUSION: The prevalence of AO or DJK at ultimate follow-up for AIS with LIV at L3 was 13.1%. To prevent AO or DJK following fusion to L3, we recommend that the CSVL touch L3 in both standing and side bending, TS score is -4 or less, the L3/4 disc is flexible, L3 is neutral (<15°) and ≤2 cm from the midline and the patient is ≥ Risser 2.

The Incidence of Adding-On or Distal Junctional Kyphosis in Adolescent Idiopathic Scoliosis Treated by Anterior Spinal Fusion to L3 Was Significantly Higher Than by Posterior Spinal Fusion to L3.

OBJECTIVE: To compare and identify risk factors for distal adding-on (AO) or distal junctional kyphosis (DJK) in adolescent idiopathic scoliosis (AIS) treated by anterior- (ASF) and posterior spinal fusion (PSF) to L3. METHODS: AIS patients undergoing ASF versus PSF to L3 from 2000-2010 were analyzed. Distal AO and DJK were deemed poor radiographic results. New stable (SV) and neutral vertebra (NV) scores were defined for this study. The total stability (TS) score was the sum of the SV and NV scores. RESULTS: Twenty of 42 (ASF group: 47.6%) and 8 of 72 patients (PSF group: 11.1%) showed poor radiographic outcome. Fused vertebrae, correction rate of main curve, coronal reduction rate of L3 were significantly higher in PSF group. Multiple logistic regression results indicated that preoperative SV-3 at L3 in standing and side benders (odds ratio [OR], 2.7 and 3.7, respectively), TS score -5, -6 at L3 (OR, 4.9), rigid disc at L3-4 (OR, 3.7), lowest instrumented vertebra (LIV) rotation > 15° (OR, 3.3), LIV deviation > 2 cm from center sacral vertical line (OR, 3.1) and ASF (OR, 13.4; p < 0.001) were independent predictive factors. There was significant improvement of the Scoliosis Research Society (SRS)-22 average scores only in PSF group. Furthermore, the ultimate scores of PSF group were significantly superior to ASF group. CONCLUSION: The prevalence of AO or DJK at ultimate follow-up for AIS with LIV at L3 was significantly higher in ASF group. Ultimate SRS-22 scores were significantly better in PSF group.

Selecting the "Touched Vertebra" as the Lowest Instrumented Vertebra in Patients with Lenke Type-1 and 2 Curves: Radiographic Results After a Minimum 5-Year Follow-up.

BACKGROUND: The selection of the lowest instrumented vertebra (LIV) in patients with adolescent idiopathic scoliosis (AIS) is still controversial. Although multiple radiographic methods have been proposed, there is no universally accepted guideline for appropriate selection of the LIV. We developed a simple and reproducible method for selection of the LIV in patients with Lenke type-1 (main thoracic) and 2 (double thoracic) curves and investigated its effectiveness in producing optimal positioning of the LIV at 5 years of follow-up. METHODS: The radiographs for 299 patients with Lenke type-1 or 2 AIS curves that were included in a multicenter database were evaluated after a minimum duration of follow-up of 5 years. The "touched vertebra" (TV) was selected on preoperative radiographs by 2 independent examiners. The LIV on postoperative radiographs was compared with the preoperative TV. The final LIV position in relation to the center sacral vertical line (CSVL) was assessed. The CSVL-LIV distance and coronal balance in patients who had fusion to the TV were compared with those in patients who had fusion cephalad and caudad to the TV. The sagittal plane was also reviewed. RESULTS: In 86.6% of patients, the LIV was selected at or immediately adjacent to the TV. Among patients with an "A" lumbar modifier, those who had fusion cephalad to the TV had a significantly greater CSVL-LIV distance than those who had fusion to the TV (p = 0.006) or caudad to the TV (p = 0.002). In the groups with "B" (p = 0.424) and "C" (p = 0.326) lumbar modifiers, there were no differences among the TV groups. CONCLUSIONS: We recommend the TV rule as a third modifier in the Lenke AIS classification system. Selecting the TV as the LIV in patients with Lenke type-1 and 2 curves provides acceptable positioning of the LIV at long-term follow-up. The position of the LIV was not different when fusion was performed caudad to the TV but came at the expense of fewer motion segments. Patients with lumbar modifier "A" who had fusion cephalad to the TV had greater translation of the LIV, putting these patients at risk for poor long-term outcomes. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Minimum five-year follow-up of posterior-only pedicle screw constructs for thoracic and thoracolumbar kyphosis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To review/report 5-year follow-up data on patients diagnosed with thoracic and thoracolumbar kyphosis (TK/TLK) treated with posterior-only spinal fusion. TK/TLK was initially treated with combined anterior/posterior spinal fusion, evolving into widespread treatment with posterior-only spinal fusion. METHODS: Forty-three patients who underwent a posterior-only spinal fusion for a primary diagnosis of TK/TLK from 1999 to 2009 with > 5-year follow-up were identified. Preoperative/postoperative/final follow-up measurements were recorded from full-length standing radiographs. Prospectively collected outcome scores were reviewed for the same time points, and charts were examined for complications. RESULTS: Patient age averaged 33 years (range 13-77), and follow-up averaged 5.6 years (range 5-12.2). Diagnoses included Scheuermann's disease (N = 15, 35%), idiopathic (N = 10, 23%), pseudarthrosis (N = 6, 14%), iatrogenic (N = 4, 9%), degenerative (N = 3, 7%), post-traumatic (N = 3, 7%), and congenital kyphosis (N = 2, 5%). Average correction of 44.3° (46%; 92.8° preoperatively vs 48.5° postoperatively) was achieved through posterior-only surgery. Loss of correction averaged only 1° in the instrumented segments at final follow-up. Eleven patients had a complication; proximal junctional kyphosis was the most common (N = 3, 7%). One patient lost intraoperative monitoring and one had temporary neurological deterioration postoperatively, but there was no permanent deficit. No pseudarthroses occurred. ODI scores improved 17.2 points on average (p = 0.01). SRS scores improved in all domains (average 0.79, p < 0.001). CONCLUSION: Pedicle screw constructs permit effective posterior-only correction of TK/TLK that is maintained at the 5-year follow-up time point. Patients report improvement, via outcome questionnaires, at the same follow-up time points. These slides can be retrieved under Electronic Supplementary Material.

Comparison of Single-Level Versus Multilevel Vertebral Column Resection Surgery for Pediatric Patients With Severe Spinal Deformities.

STUDY DESIGN: Retrospective cohort of pediatric patients (younger than 21 years) with severe spinal deformities who underwent vertebral column resection (VCR) surgery. OBJECTIVE: To compare patients who underwent single- versus multilevel VCR surgery in terms of radiographic correction and perioperative complications. SUMMARY OF BACKGROUND DATA: There are few studies comparing single- to multilevel VCR surgery regarding the efficacy and safety of the procedures. METHODS: Eighty-two pediatric patients who underwent a VCR for severe spinal deformity between 2002 and 2012 by one surgeon were included. A single-level VCR was performed in 45 patients with an average of 4.7-year follow-up, and multilevel VCR in 37 patients with an average of 4.6-year follow-up. RESULTS: Coronal Cobb corrections were not different between groups (single level: 63%, multilevel: 58%, P = 0.146). Correction loss at final follow-up did not differ (3.1° vs. 0.3°, P = 0.132). Patients in the single-level group had shorter operation times (9.2 vs. 10.5 hours, P = 0.046), whereas estimated blood loss did not differ between the two groups (1061 vs. 1200 mL, P = 0.181). The rate of spinal cord monitoring events was 20% (8/40) and 30% (9/30), respectively. No patient in the single-level group had a postoperative neurologic deficit, whereas three patients in the multilevel group experienced a temporary deficit postoperatively (0/45 vs. 3/37, P = 0.088). CONCLUSION: There was no difference in radiographic correction between the single- and multilevel VCR groups. The multilevel VCR patients had longer operative times, and although the differences were not statistically significant due to low sample size, the multilevel VCR group also had an increased rate of postoperative neurologic deficits. We would recommend single-level VCRs unless there is an absolute indication for multilevel resection as in necessary decompression for spinal cord impingement. LEVEL OF EVIDENCE: 4.

Clinical and Radiographic Outcomes After Posterior Vertebral Column Resection for Severe Spinal Deformity with Five-Year Follow-up.

BACKGROUND: Short-term studies have shown improved outcomes and alignment after posterior vertebral column resection for severe spinal deformity. Our goal was to report long-term changes in radiographic and health-related quality-of-life measures in a consecutive series of pediatric and adult patients undergoing posterior vertebral column resection with a minimum follow-up of 5 years. METHODS: We reviewed all patients undergoing posterior vertebral column resection by a single surgeon prior to January 1, 2010, at a single institution. Standard preoperative and perioperative data were collected, including the Scoliosis Research Society (SRS)-22/24 instrument. Radiographic and health-related quality-of-life measures changes were evaluated at a minimum follow-up of 5 years. RESULTS: One hundred and nine patients underwent posterior vertebral column resection prior to January 2010, and 54 patients (49.5%) were available for analysis: 31 (57.4%) were pediatric patients, and 23 (42.6%) were adult patients. The mean age (and standard deviation) was 12.5 ± 3 years for the pediatric cohort and 39.3 ± 20 years for the adult cohort. Improvements in the mean major Cobb angle at a minimum follow-up of 5 years were seen: 61.6% correction for the pediatric cohort and 53.9% correction for the adult cohort. The rates of proximal junctional kyphosis, defined as proximal junctional kyphosis of >10°, were 16.1% for the pediatric cohort and 34.8% for the adult cohort, but none underwent a revision surgical procedure for symptomatic proximal junctional kyphosis. Of the 54 patients, 30 (55.6%) sustained complications, 5 (9.3%) experienced postoperative neurological deficits, and 7 (13.0%) required a revision by 5 years postoperatively. Significant improvements were observed in the SRS-Self Image with regard to the pediatric cohort at 0.9 (p = 0.017) and the adult cohort at 1.3 (p = 0.002) and in the SRS-Satisfaction with regard to the pediatric cohort at 1.8 (p = 0.008) and the adult cohort at 1.3 (p = 0.005). CONCLUSIONS: Posterior vertebral column resection offers substantial, sustained improvements in global radiographic alignment and patient outcome scores at 5 years. The major radiographic deformity was reduced by 61.6% in the pediatric cohort and by 53.9% in the adult cohort. Despite the high rate of complications, patients experienced significant improvement in the SRS-Self Image and SRS-Satisfaction domains. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The cranial sagittal vertical axis (CrSVA) is a better radiographic measure to predict clinical outcomes in adult spinal deformity surgery than the C7 SVA: a monocentric study.

PURPOSE: Our study aimed to confirm the correlation between the Cranial Sagittal Vertical Axis (CrSVA) and patient-reported outcomes and to compare clinical correlation between CrSVA and C7 SVA in adult spinal deformity (ASD) patients. METHODS: 108 consecutive ASD patients were evaluated using the EOS® 2D/3D radio-imaging device. A vertical plumb line from the cranial center was utilized to measure the distance to the posterior corner of S1 (CrSVA-S), and to the centers of the hip (CrSVA-H), the knee (CrSVA-K), and ankle (CrSVA-A), as well as measuring the standard C7 SVA. We analyzed the correlation between each CrSVA parameter with the Oswestry Disability Index (ODI) and Scoliosis Research Society form (SRS-22r). RESULTS: All 4 CrSVA measures demonstrated strong correlation with the ODI and SRS-22r total score and the pain, self-image, and function subscores. Of note, CrSVA-A (Global SVA) also strongly correlated with the SRS satisfaction subscore. Univariate linear regression showed similar results. The strongest predictor of outcomes was CrSVA, not C7 SVA; (CrSVA-H for ODI, SRS total score, and the pain, self-image, and function subscores; and Global SVA for satisfaction and mental health subscores). CONCLUSIONS: The clinical correlation effect of outcome scores to the CrSVA measures is validated. Global SVA has an especially strong correlation with ODI and all the SRS subscores. Our study confirms that CrSVA is a stronger predictor of preoperative clinical outcomes than the C7 SVA in adult deformity patients.

Results of Revision Surgery for Proximal Junctional Kyphosis Following Posterior Segmental Instrumentation: Minimum 2-Year Postrevision Follow-Up.

STUDY DESIGN: A retrospective cohort study. OBJECTIVES: The aim of this study was to evaluate radiographic and patient-reported outcomes at minimum 2 years after revision surgery for proximal junctional kyphosis (PJK), correlating these results with PJK etiology. SUMMARY OF BACKGROUND DATA: There are no studies detailing the results of revision surgery for PJK following posterior segmental instrumentation. METHODS: Thirty-two consecutive patients treated with revision surgery after PJK above posterior fusions (25 women/7 men, average age at surgery 60.6 yrs) were reviewed for radiographic and patient-reported outcomes (mean follow-up, 4.5 yrs; range, 2-10 yrs). Patients were subdivided into fracture (F) and nonfracture (NF) groups on the basis of PJK etiology. RESULTS: Radiographic severity of PJK improved significantly with revision surgery and was maintained at ultimate follow-up (P < 0.001). However, initial sagittal vertical axis (SVA) correction was not maintained through ultimate follow-up (P = 0.04). There were significant postrevision improvements in mean Oswestry scores (P < 0.001) and SRS total scores (P < 0.001) in all patients. In patients with pelvic incidence-lumbar lordosis (PI-LL) mismatch < 11°, final PJK measurement was smaller than in patients with mismatch ≥11° (9.4° vs. 19.8°, P = 0.009). Six patients (19%) developed new postrevision PJK, with two (6%) requiring additional surgery. Patients who sustained PJK through a fracture had greater improvements in Oswestry (P = 0.004), total SRS (P = 0.04), pain (P < 0.001), and satisfaction (P = 0.05) scores, although the fracture patients had less maintained SVA correction (P = 0.002). CONCLUSION: Revision surgery for PJK following posterior instrumentation achieved acceptable radiographic and clinical outcomes at minimum 2-year follow-up. Patients with PI-LL mismatch <11° experienced more ultimate PJK correction than patients with mismatch ≥11°. Although the NF group experienced more sustained correction of sagittal balance, the F group reported greater improvements in patient-reported outcomes. Ultimate clinical outcomes after revision surgery for PJK were similar between patients with and without compression fractures. LEVEL OF EVIDENCE: 3.

Long-term radiographic outcomes of a central hook-rod construct for osteotomy closure: minimum 5-year follow-up.

STUDY DESIGN: Retrospective study. OBJECTIVE: To evaluate long-term effectiveness of central hook-rod constructs for posterior spinal osteotomy closure. SUMMARY OF BACKGROUND DATA: During osteotomy site closure various techniques are used, including patient positioning, rod cantilevering, extending fixation points, and compressing through pedicle fixation points. All add premature stress on fixation points and may lead to loosening/eventual fixation failure. To avoid this, we often use a central compression hook-rod construct for osteotomy closure. METHODS: Fifty-six consecutive patients with fixed sagittal imbalance were treated with multilevel posterior column osteotomies (N = 19), pedicle subtraction osteotomy (N = 31), or vertebral column resection (N = 6). All 56 patients had undergone osteotomy closure using central compression hook-rod constructs and were analyzed at a follow-up of 5 years or more. Compression hooks were inserted into the fusion mass or lamina above/below the osteotomy and centrally attached to a short rod connected to pedicle screw-based rods via a cross-link. Diagnoses included sagittal imbalance associated with scoliosis (N = 39), degenerative sagittal imbalance (N = 14), ankylosing spondylitis (N = 2), and Scheuermann's kyphosis (N = 1). There were 55 revision cases and 1 primary. Radiographic/clinical analysis was performed to evaluate the efficacy/complications of this technique. RESULTS: Overall lumbar lordosis increased an average of 31.7° and local lordosis through the osteotomy site increased an average of 29.3°. Sagittal balance improved by an average of 92 mm. In all cases, osteotomy closures were performed without screw loosening or loss of correction intraoperatively. At a follow-up of 5 years or more, no failures of the hook-rod construct were seen, but there were 3 patients with partial implant failure; however, no symptomatic pseudarthroses at the osteotomy sites occurred. Seven patients developed pseudarthrosis below the central hook-rod construct. CONCLUSION: A central hook-rod construct is safe, controlled, and effective for applying compressive forces to close various spinal osteotomies without fixation failure or pseudarthrosis at the osteotomy site noted at a follow-up of 5 or more years. It adds fixation strength to the overall construct avoiding undue stress on pedicle screws. LEVEL OF EVIDENCE: 3.

Predicting Kyphosis Correction During Posterior-Only Vertebral Column Resection by the Amount of Spinal Column Shortening.

STUDY DESIGN: Retrospective. OBJECTIVE: To investigate the relationship between the amount of correction achieved (K°) and extent of vertebral column shortening (mm) with posterior vertebral column resection (PVCR). SUMMARY OF BACKGROUND DATA: There is no scientific reference to the correlation between K° and column shortening (mm) with PVCR. METHODS: Based on simple geometry, we tested the hypothesis that we could predict the amount of actual kyphosis correction (K°) by calculation on 26 kyphotic PVCR patients. Using multiple linear measurements (mm), two angular approximations (°) were calculated: the geometric approximation (G°) using the geometric calculation (G-cal), and the rough approximation (R°) by more simplistic calculation (R-cal). Both G° and R° were compared against K° as measured on the pre- and postoperative radiographs. If calculated G° and R° is close to measured K°, we can use the calculations (G-cal and R-cal) in the clinical situation. RESULTS: The mean correction of K° was 38°. K°-G° and K°-R° were not significantly greater than 3° and 6°, respectively. As K° was very close to G° and R°, K° can replace G° and R°. Therefore, we can use G-cal and R-cal in the clinical setting and we can determine how much posterior shortening and what cage size is required to obtain a certain amount of K°. CONCLUSIONS: With two calculations (G-cal & R-cal), we can determine how much vertebral column shortening (mm) we need during PVCR to obtain the amount of kyphosis correction desired (K°). In order to obtain K°, using the formula deduced from G-cal and R-cal, we can determine the shortening between the upper and lower pedicle screws and cage size.

Comparison of standard 2-rod constructs to multiple-rod constructs for fixation across 3-column spinal osteotomies.

STUDY DESIGN: Retrospective matched-cohort comparative study. OBJECTIVE: Compare radiographical outcomes after the use of a standard 2-rod construct (2-RC) versus a multiple-rod construct (multi-RC) across 3-column osteotomy sites in a matched cohort with severe kyphosis and/or scoliosis with minimum 2-year follow-up. SUMMARY OF BACKGROUND DATA: Three-column osteotomies are used for treating severe spinal deformities, typically with a standard 2-RC across the highly unstable osteotomy site. METHODS: Between 1996 and 2010, patients undergoing a 3-column osteotomy by a single surgeon were matched for age/diagnosis/vertebra(e) resected/levels fused and curve magnitude. Sixty-six control patients with a 2-RC were identified and appropriately matched to 66 consecutive patients with a multi-RC across the 3-column osteotomy site. Each group included 50 patients with lumbar pedicle subtraction osteotomy and 16 patients with vertebral column resection. Radiographs were measured using standard adult deformity criteria. RESULTS: Averages were compared for 2-RC versus multi-RC demonstrating no statistical differences in mean age at surgery, vertebrae resected, levels fused, bone morphogenetic protein used (patients), or average preoperative Cobb magnitude. There were significant differences in the occurrence of rod breakage and revision surgery for pseudarthroses at the 3-column osteotomy site (rod breakage: 2-RC: 11 vs. multi-RC: 2, P=0.002; and revision: 2-RC: 6 vs. multi-RC: 0, P=0.011). There was no complete implant failure in the multi-RC group but 2 patients had partial implant failure without symptomatic pseudarthrosis. Eight patients in each group (12%) developed a pseudarthrosis above or below the osteotomy site. CONCLUSION: The use of a multi-RC is a safe, simple, and effective method to provide increased stability across 3-column osteotomy sites to significantly prevent implant failure and symptomatic pseudarthrosis versus a standard 2-RC. We strongly recommend using a multi-RC to stabilize 3-column osteotomies of the thoracic and lumbar spine. LEVEL OF EVIDENCE: 3.

Results of revision surgery after pedicle subtraction osteotomy for fixed sagittal imbalance with pseudarthrosis at the prior osteotomy site or elsewhere: minimum 5 years post-revision.

STUDY DESIGN: Retrospective review of pedicle subtraction osteotomy (PSO) cases. OBJECTIVE: To report our results, radiographic and clinical outcomes at a minimum 5 years following revision surgery for pseudarthrosis after a PSO. SUMMARY OF BACKGROUND DATA: To our knowledge, there is no report on the results of revision surgery for pseudarthrosis after a PSO. METHODS: Eighteen consecutive patients with pseudarthrosis after PSO (16 females/2 males; average age at surgery, 49.8 yr) treated with revision surgery at one institution were analyzed (average follow-up, 6.5 yr; range, 5-12 yr). Radiographic and clinical outcomes analysis was performed. RESULTS: Sagittal vertical axis (SVA) and lumbar lordosis (LL) improved significantly after revision surgery (SVA, P = 0.000; LL, P = 0.024) and were maintained until ultimate post-revision follow-up (SVA, P = 0.170; LL, P = 0.729). Proximal junctional angle (P = 0.828), thoracic kyphosis (P = 0.828), and PSO angle (P = 0.717) achieved by the primary surgery were also maintained until ultimate post-revision. We increased the number of rods and/or changed them to 6.35-mm diameter in all patients. There were significant improvements post-revision in Oswestry Disability Index (45 vs. 37.9, P = 0.041) and Scoliosis Research Society pain subscale (2.6 vs. 3.1, P = 0.047) but not in Scoliosis Research Society total score or other subscales. Pelvic incidence greater than 60° demonstrated a trend toward poorer Oswestry Disability Index and Scoliosis Research Society scores (P > 0.05), but there were no significant differences between SVA greater or less than 11 cm. CONCLUSION: Revision surgery for pseudarthrosis after PSO can provide acceptable radiographic and clinical outcomes at a minimum 5 years post-revision. Successful surgical outcomes may be achieved by using an increased number or size of implants and ample bone graft for complete fusion after revision surgery. LEVEL OF EVIDENCE: 4.

Complications after 147 consecutive vertebral column resections for severe pediatric spinal deformity: a multicenter analysis.

STUDY DESIGN: Retrospective multicenter review. OBJECTIVE: Determine the definition, indications, results, and outcomes, focusing on complications of vertebral column resection (VCR) for severe pediatric spinal deformity. SUMMARY OF BACKGROUND DATA: The strict definition of the VCR procedure, indications, results, outcomes, and the numerous, potentially serious complications are unknown or controversial, and a large multicenter review has never been performed. METHODS: A total of 147 patients treated by 7 pediatric spinal deformity surgeons were reviewed-seventy-four females and 73 males, with an average age of 13.7 years, an average of 1.6 (range, 1-5) vertebrae resected, and an average follow-up of 17 months (range, 0.5-64 mo). The strict definition of VCR used was a "3-column circumferential vertebral osteotomy creating a segmental defect with sufficient instability to require provisional instrumentation." RESULTS: Indications for a VCR were divided into 5 diagnostic categories: kyphoscoliosis (n = 52), severe scoliosis (n = 37), congenital deformity (n = 28), global kyphosis (n = 17), and angular kyphosis (n = 13). Eighty-four primary and 63 revision patients with 174 operative procedures, 127 posterior-only (17 staged), and 20 patients combined anterior-posterior (10 staged) were reviewed. Average preoperative upright, flexibility, and postoperative Cobb measures (% correction or average kyphosis decrease) were kyphoscoliosis: 91°, 65°, 44° (51% coronal), 104°, 81°, and 47° (decrease, 57° sagittal); severe scoliosis: 104°, 78°, and 33° (67%); congenital deformity: 47°, 38°, 22° (46% coronal), 56°, 48°, and 32° (decrease, 24° sagittal); global kyphosis: 101°, 79°, and 47° (decrease, 54°); and angular kyphosis: 88°, 90°, and 38° (decrease, 50°), respectively. Operative time averaged 545 minutes (range, 204-1355 min) and estimated blood loss averaged 1610 mL (range, 50-8244 mL) for an average 65% blood volume loss (range, 6%-316%). Eighty-six patients (59%) developed a complication, 39 patients (27%) having an intraoperative neurological event (spinal cord monitoring change or failed wake-up test); however, no patient had complete permanent paraplegia. CONCLUSION: A total of 147 consecutive pediatric VCRs performed by 7 surgeons demonstrated excellent radiographical correction. However, these complex reconstructions were associated with a 59% complication rate, thus emphasizing the challenging nature of these patients and procedures.

Rapidly progressive Scheuermann's disease in an adolescent after pectus bar placement treated with posterior vertebral-column resection: case report and review of the literature.

STUDY DESIGN: Case report and review of the literature. OBJECTIVE: This case illustrates the importance of the costosternal complex in maintaining the stability and alignment of the thoracic spine. The patient was iatrogenically destabilized by placement of a pectus bar leading to rapid symptomatic progression of his Scheuermann's kyphosis, ultimately requiring surgical correction. SUMMARY OF BACKGROUND DATA: Scheuermann's kyphosis is a disease process defined by strict radiographical and clinical criteria. Surgical treatment is generally recommended for curves greater than 75°. This case demonstrates the critical role of the costosternal complex in maintaining the stability of the thoracic spine. The patient described in this report underwent placement of a pectus bar for correction of symptomatic pectus excavatum. He subsequently developed a progressive symptomatic Scheuermann's kyphosis as a result of the destabilization of his costosternal complex. This patient ultimately required removal of the pectus bar and posterior instrumented kyphosis correction. METHODS: Progressive symptomatic Scheuermann's kyphosis (105°) corrected by removal of the pectus bar, T11 posterior vertebral-column resection and T4-L3 instrumented posterior spinal fusion. RESULTS: The patient had an uneventful immediate postoperative course. He was discharged neurologically intact with dramatic kyphosis correction and significant symptomatic improvement. Radiographs obtained 3 years postoperatively reveal stable thoracolumbar correction. CONCLUSION: The costosternal complex plays a critically important role in the intrinsic stability of the thoracic spine. Iatrogenic disruption of the costosternal complex can result in rapid progression of thoracic/thoracolumbar kyphosis in the setting of Scheuermann's disease.

Vertebral column resection for the treatment of severe spinal deformity.

UNLABELLED: The ability to treat severe pediatric and adult spinal deformities through an all-posterior vertebral column resection (VCR) has obviated the need for a circumferential approach in primary and revision surgery, but there is limited literature evaluating this new approach. Our purpose was therefore to provide further support of this technique. We reviewed 43 patients who underwent a posterior-only VCR using pedicle screws, anteriorly positioned cages, and intraoperative spinal cord monitoring between 2002 and 2006. Diagnoses included severe scoliosis, global kyphosis, angular kyphosis, or kyphoscoliosis. Forty (93%) procedures were performed at L1 or cephalad in the spinal cord (SC) territory. Seven patients (18%) lost intraoperative neurogenic monitoring evoked potentials (NMEPs) data during correction with data returning to baseline after prompt surgical intervention. All patients after surgery were at their baseline or showed improved SC function, whereas no one worsened. Two patients had nerve root palsies postoperatively, which resolved spontaneously at 6 months and 2 weeks. Spinal cord monitoring (specifically NMEP) is mandatory to prevent neurologic complications. Although technically challenging, a single-stage approach offers dramatic correction in both primary and revision surgery of severe spinal deformities. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Posterior vertebral column resection for severe pediatric deformity: minimum two-year follow-up of thirty-five consecutive patients.

STUDY DESIGN: Retrospective review of a prospectively accrued patient cohort. OBJECTIVE: The ability to treat severe pediatric spinal deformity through an all-posterior vertebral column resection (VCR) has obviated the need for a circumferential approach in both primary and revision settings. We examined indications, correction rates, and complications of this challenging procedure in the pediatric population. SUMMARY OF BACKGROUND DATA: Traditionally, severe pediatric spinal deformities were treated through a combined anterior/posterior spinal fusion. METHODS: Between 2000 and 2005, 35 consecutive patients underwent a posterior-only VCR by 1 of 2 surgeons at a single institution. Patients were divided into 5 diagnostic categories: (1) severe scoliosis (S) (n = 2; mean, 115 degrees; range, 79-150 degrees; average flexibility, 12%); (2) global kyphosis (GK) (n = 3; mean, 101 degrees; range, 91-113 degrees; average flexibility, 16%); (3) angular kyphosis (AK) (n = 10; mean, 86 degrees; range, 45-135 degrees, average flexibility, 23%); (4) kyphoscoliosis (KS) (n = 8; mean kyphosis, 103 degrees/scoliosis 87 degrees; mean combined, 190 degrees; range, 144-237 degrees); (5) congenital scoliosis (CS) (n = 12; mean, 43 degrees; range, 23-69 degrees; average flexibility, 20%). There were 20 primary/15 revision surgeries. There were 20 one-level, 11 two-level, and 4 three-level resections. RESULTS: The major curve correction averaged: Group S = 61 degrees/51%, Group GK = 56 degrees/55%, Group AK = 51 degrees/58%, Group KS = 98 degrees/54%, and Group CS = 24 degrees/60%. The average OR time was 460 minutes (range, 210-822), with an average EBL of 691 mL (range, 125-2200). There were no spinal cord-related complications; however, 2 patients (8.5%) lost intraoperative neuromonitoring data during correction with data returning to baseline following prompt surgical intervention. Two patients had implant revisions, 1 for a delayed deep infection at 2 years and the other for implant prominence at 3-year follow-up. CONCLUSION: A posterior-based VCR is a safe but challenging technique to treat severe primary or revision pediatric spinal deformities. Intraoperative SCM (especially motor-evoked potentials) is mandatory to prevent spinal cord-related neurologic complications. Dramatic radiographic and clinical correction of these deformities can be obtained via a posterior-only approach.

Comparison of Scheuermann kyphosis correction by posterior-only thoracic pedicle screw fixation versus combined anterior/posterior fusion.

STUDY DESIGN: Retrospective comparison review. OBJECTIVE: Compare posterior-only treatment results with segmental thoracic pedicle screw constructs versus combined anterior/posterior fusion in patients with Scheuermann kyphosis. SUMMARY OF BACKGROUND DATA: Traditionally, operative Scheuermann kyphosis has been treated with combined anterior/posterior spinal fusion, with the anterior portion being performed via an open thoracotomy or a video-assisted thoracoscopic approach. METHODS: There were 18 patients with Scheuermann kyphosis who underwent a posterior-only thoracic pedicle screw (P/TPS) fusion and 21 who underwent an anterior/posterior fusion who were followed for a 2-year minimum. The 2 groups were well matched according to average age (anterior/posterior fusion 18.0 degrees and P/TPS 17.3 degrees; P = 0.60), maximum preoperative kyphosis (anterior/posterior fusion 89.1 degrees and P/TPS 84.4 degrees; P = 0.21), flexibility index (anterior/posterior fusion 0.408 degrees and P/TPS 0.407 degrees; P > 0.99), and posterior fusion levels (anterior/posterior fusion 12.1 degrees and P/TPS 12.2 degrees; P = 0.95). Of 21 patients with anterior/posterior fusions, zero versus 12 of 18 (67%) patients in the P/TPS group underwent apical Smith-Petersen osteotomies. Fixation in the anterior/posterior fusion group was achieved with hybrid hook/screw constructs. Posterior fixation in the P/TPS group was performed using segmental thoracic pedicle screw constructs. Both groups had posterior iliac bone autografting. Operating time and blood loss were noted, and radiographs were evaluated before surgery, after surgery, and at final follow-up. At final follow up, Scoliosis Research Society-30 questionnaire data and complications were recorded. RESULTS: At surgery, operating time and blood loss were significantly less in the P/TPS group (P = 0.009 and P = 0.05, respectively). The mean residual kyphosis of the P/TPS group averaged 38.2 degrees after surgery and 40.4 degrees at final follow-up versus anterior/posterior fusion group (51.9 degrees and 58.0 degrees, P < 0.001 and P = 0.001, respectively). Even without an anterior release, kyphosis correction in the P/TPS group averaged 54.2% after surgery and 51.8% at final follow-up versus the anterior/posterior fusion group (41.2% and 38.5%, P = 0.001 and P < 0.001, respectively). Scoliosis Research Society-30 outcome scores at final follow-up were comparable between the 2 groups (P/TPS = 120 and anterior/posterior fusion = 128; P = 0.14). The anterior/posterior fusion group had 8/21 (38%) patients with complications, including paraplegia in 1, proximal junctional kyphosis in 1, proximal hook pullout in 1, and infection in 2. The P/TPS group had no complications (P = 0.003). CONCLUSIONS: With less operating time and intraoperative blood loss, posterior-only Scheuermann kyphosis treatment with thoracic pedicle screws achieved and maintained better correction, and had significantly less complications than with circumferential fusion.

Analysis of the lowest instrumented vertebra following anterior spinal fusion of thoracolumbar/lumbar adolescent idiopathic scoliosis: can we predict postoperative disc wedging?

STUDY DESIGN: A retrospective radiographic study. OBJECTIVES: To investigate which radiographic parameters correlate best to ultimate lowest instrumented vertebra (LIV) position and subjacent disc wedging following anterior spinal fusion (ASF) for thoracolumbar/lumbar (TL/L) adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: In an ASF of TL/L AIS, part of the operative goals are often to horizontalize and centralize the LIV, or potentially minimize subjacent disc wedging after surgery. To our knowledge, no study has investigated the specific radiographic parameters involved with obtaining these goals. METHODS: Sixty-one patients with TL/L AIS were treated with an instrumented ASF with a minimum 2-year follow-up. Preoperative and postoperative radiographs were examined measuring various radiographic parameters of the curve itself along with the LIV and subjacent disc. Specific correlation of these parameters to the coronal disc angle immediately below the LIV (disc angle), LIV translation, and global coronal balance (C7-CSVL distance) at 2 years postoperative was analyzed, respectively. RESULTS: The preoperative disc angle was 4.49 degrees +/- 5.48 and postoperative -5.85 degrees +/- 4.37. The change of the disc angle was significantly correlated to the LIV level relative to the preoperative lower end vertebra (LEV) (P < 0.006). Regressive analysis demonstrated the correlative parameters to the postoperative disc angle to be: preoperative upright disc angle; preoperative apex-LIV distance; and preoperative T12-LIV lordosis (P < 0.0001, r2 = 0.51). The correlative parameters to postoperative LIV translation were preoperative LIV translation and preoperative LIV rotation (P = 0.002, r2 = 0.2). The correlative parameter to postoperative C7-CSVL distance was only preoperative C7-CSVL distance (P < 0.0001, r2 = 0.3). CONCLUSIONS: Postoperative subjacent disc wedging occurs most often when the preoperative subjacent disc is nearly parallel and when a shorter fusion excluding the LEV is performed. Preoperative LIV rotation significantly correlates to postoperative LIV translation. Surgeons should note these preoperative predictive factors to optimize radiographic results of the operative treatment of TL/L AIS.

Prospective pulmonary function comparison of open versus endoscopic anterior fusion combined with posterior fusion in adolescent idiopathic scoliosis.

STUDY DESIGN: Prospective clinical study. OBJECTIVE: To evaluate pulmonary function tests at a minimum 2-year follow-up in patients with adolescent idiopathic scoliosis (AIS) undergoing either an endoscopic versus open anterior fusion along with posterior segmental fixation and fusion. METHODS: A total of 21 patients with AIS underwent a video-assisted thoracoscopic (VAT group) release/fusion followed by a posterior spinal fusion (PSF) and segmental spinal fixation were compared to 16 patients who underwent an open thoracotomy (Open group) followed by a PSF. The mean preoperative thoracic Cobb was 70 degrees in the VAT group versus 75 degrees in the Open group. All patients had preoperative and a minimum 2-year postoperative pulmonary function tests consisting of forced vital capacity (FVC) forced expiratory volume in one second (FEV-1). RESULTS: The average thoracic Cobb correction was to 27 degrees (61%) in the VAT group versus 36 degrees (52%) in the Open group. Preoperative and 2-year postoperative FVC in the VAT group averaged 2.48 L and 2.85 L, respectively (P = 0.006). The Open group corresponding results were 1.97 L and 2.43 L, respectively (P = 0.001). Preoperative and minimum 2-year postoperative FEV-1 in the VAT group averaged 2.06 L and 2.37 L, respectively (P = 0.005). Values for the Open group were 1.65 L and 2.08 L, respectively (P = 0.001). Although both groups had pulmonary function test parameters that were statistically improved postoperative versus preoperative, there were no significant differences comparing the VAT group to the Open group (P > 0.05) CONCLUSIONS: VAT versus Open release/anterior fusion in association with a PSF for select AIS curves requiring circumferential treatment both demonstrated similar radiographic and pulmonary function test improvement at 2 years postoperative, with no significant differences seen between the groups.

Evaluation of ventilatory efficiency during exercise in patients with idiopathic scoliosis undergoing spinal fusion.

STUDY DESIGN: A prospective evaluation of ventilatory function following spinal fusion in adolescent idiopathic scoliosis. OBJECTIVES: To prospectively evaluate pulmonary function, maximal oxygen uptake, and ventilatory efficiency during exercise in patients with adolescent idiopathic scoliosis before surgery and a minimum of 2 years postoperation. SUMMARY OF BACKGROUND DATA: For reasons that are unclear, patients with untreated adolescent idiopathic scoliosis tend to avoid aerobic exercise. Their reluctance may be the result of low ventilatory efficiency, as they often approach their ventilatory ceiling at maximum oxygen uptake despite forced vital capacities that are near normal. This inefficiency of ventilation with exercise may explain the reluctance of patients with scoliosis to pursue aerobic fitness. No study has evaluated the effect spinal fusion has on the ventilatory function of patients with scoliosis during exercise. METHODS: Forty-two patients with adolescent idiopathic scoliosis (36 female and 6 male) at an average age of 14 +/- 3 years (range 10-18 years) underwent spinal fusion. Twenty patients underwent a posterior spinal fusion alone, 20 an anterior spinal fusion alone, and 2 an anterior spinal fusion and posterior spinal fusion. The average Cobb measurement was 55 degrees (range 40-85 degrees). Pulmonary function values (forced vital capacity, total lung capacity, maximum voluntary ventilation), maximum oxygen uptake (VO2max), and ventilatory efficiency were obtained before surgery and a minimum of 2 years postoperation. RESULTS: For all patients, forced vital capacity percent predicted decreased from 88.1% to 81.4% (P < 0.0001). Total lung capacity also declined from 90.5% to 88.5% but was not statistically significant (P = 0.189). Percent predicted maximum oxygen uptake (VO2max) declined from 93.6% to 85.1% (P = 0.00029). Ventilatory efficiency, as measured by VEmax/maximum voluntary ventilation, improved from 0.76 to 0.68 (P = 0.005), whereas measured by VEmax/FEV1 x 40 was unchanged from 0.69 to 0.70 (P = 0.172) postoperation. The choice of operative approach [anterior (n = 20) versus posterior (n = 20)] or whether rib graft was harvested (n = 33) versus iliac crest graft (n = 7) did not change these results. CONCLUSION: Improvement in ventilatory efficiency during exercise does not occur in the majority of patients with adolescent idiopathic scoliosis following spinal fusion and thus cannot be relied on to foster increases in aerobic activity.