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.

Use of the Global Alignment and Proportion score to predict postoperative health-related quality of life in adult spinal deformity surgery.

OBJECTIVE: The purpose of this study was to validate the Global Alignment and Proportion (GAP) score as a predictor of health-related quality of life (HRQOL) outcomes for patients undergoing adult spinal deformity (ASD) surgery. METHODS: This was a retrospective cohort study of patients with ASD undergoing long-segment spine fusions (≥ 5 vertebrae fused) at a single institution over a 2-year period (n = 85). Radiographic parameters were measured at preoperative, 6-week postoperative, 1-year postoperative, and 2-year postoperative visits. GAP scores were calculated using 4 sagittal parameters: relative pelvic version, relative lumbar lordosis, lordosis distribution index, and relative spinopelvic alignment. Patients were stratified into 3 GAP categories at each time point: proportioned (score 0-2), moderately disproportioned (score 3-6), and severely disproportioned (score ≥ 7). HRQOL outcomes were collected at preoperative, 1-year postoperative, and 2-year postoperative visits; these measures included patient self-reported outcome measures (i.e., PROMIS), Scoliosis Research Society-22 spinal deformity questionnaire (SRS-22), and Oswestry Disability Index (ODI) scores. RESULTS: Overall, 42% of cases were revision surgeries and 96.5% of patients underwent fusion to the sacrum. The mean preoperative GAP score significantly improved from preoperative (7.84) to immediate postoperative (3.31) assessment (p < 0.001). Similarly, the percentage of patients categorized as proportioned improved from 9.4% at preoperative to 45.9% at immediate postoperative evaluation. The preoperative GAP score or category was not significantly associated with any preoperative HRQOL outcome metrics. The immediate postoperative GAP score was not correlated with any 1-year HRQOL outcomes. However, the immediate postoperative GAP score was significantly associated with 2-year SRS-22 outcomes, including SRS-22 function (r = -0.35, p < 0.01), self-image (r = -0.27, p = 0.044), and subtotal (r = -0.35, p < 0.01) scores. As compared to severely disproportioned patients, proportioned patients had better SRS-22 pain (4.08 vs 3.17, p = 0.04), satisfaction (4.40 vs 3.50, p = 0.02), and subtotal (4.01 vs 3.27, p = 0.036) scores. The immediate postoperative GAP score was also significantly associated with 2-year PROMIS outcomes, including PROMIS pain (r = 0.31, p = 0.023) and physical function (r = -0.35, p < 0.01) scores. As compared to severely disproportioned patients, proportioned patients had better PROMIS pain (53.18 vs 63.60, p = 0.025) and physical function (41.66 vs 34.18, p = 0.017) scores. Postoperative GAP score or category did not predict any ODI outcomes. CONCLUSIONS: The postoperative GAP score is a predictor of long-term HRQOL outcomes following ASD surgery, and proportioned patients are more likely to have less pain and be satisfied with their surgery. However, the postoperative GAP score does not predict outcomes as measured by ODI.

Surgical outcomes of severe spinal deformities exceeding 100° or treated by vertebral column resection (VCR). Does implant density matter?: an observational study of deformity groupings.

STUDY DESIGN: Prospective multicenter international observational study. OBJECTIVE: To investigate the effect of implant density on clinical outcomes in complex pediatric spine reconstruction. Implant density in spine deformity surgery has been a subject of much debate with some authors advocating higher density for better correction. Few studies have looked at the effect of implant density on severe curves > 100 deg or treated with vertebral column resection (VCR). METHODS: 250/311 pts with 2-year f/u enrolled in the FOX pediatric database from 17 international sites were queried for the impact of implant density and surgical outcomes. Patients were grouped into three implant density categories for comparative analysis Group 1 (density ≤ 1), Group 2 (1 < density < 1.5) and Group 3 (density; 1.5-2). RESULTS: 250 pts: 47 (Grp1)/99 (Grp2) /104 (Grp3); Pre-op age and etiology and curve types were similar in all groups, but body mass index (BMI) was higher in Grp3. Grps 1 and 2 had significantly higher sagittal deformity angular ratio (S-DAR) compared to Grp 3 (p < 0.001). Pre-op Halo Gravity Traction (HGT) was used in 55.3%/44.4%/31.7%, p = 0.017; Grp1/Grp2/Grp3, respectively. Average duration of surgery (min) was higher in Grp3 relative to Grp1 only: 352.5/456.5/515.0, p = 0.0029. Blood loss was similar in all Grps. Rate of VCR, PSO and SPO was similar in all Grps. Pre-op Coronal Cobb avg 96.1/83.6/88.6, p = 0.2342, attained similar correction after HGT (24.6%/27.2%/23.2%, p = 0.4864. Coronal Cobb corrections at 2-year follow-up (FU) were (37.1%/40.3%/53.5%, p = 0.0004). Pre-op sagittal Cobb was (105.4/101.9/75.9, p < 0.01.), achieved similar %correction in HGT (19.1%/22.3%/22.5%, p = 0.6851) and at 2-year FU (39.6%/41.4%/29.8%, p = 0.1916). After adjusting for C-DAR, S-DAR, pre-op coronal and sagittal Cobb, etiology, curve types, age, BMI and number of rods in multivariate analysis, the odds of developing post-operative implant complication was 11 times greater in group 1 compared to group 3 (OR = 11.17,95% CI 2.34-53.32). There was significant improvement in SRS scores in all Grps at 2-year FU. CONCLUSION: Although higher implant density was observed to be associated with greater curve correction and lower rates of post-operative implant-related complication and revision in heterogeneous case groups, the results may not imply causality of implant density on the outcomes in severe pediatric spine reconstruction.

New neurologic deficit and recovery rates in the treatment of complex pediatric spine deformities exceeding 100 degrees or treated by vertebral column resection (VCR).

STUDY DESIGN: Prospective multicenter international observational study. OBJECTIVE: To investigate incidence of new neurologic deficit (NND) and the long-term recovery patterns following complex pediatric spine deformity surgery. The SRS M&M reports identify pediatric patients as having higher rate of new neurologic deficit compared with adults, while congenital and neuromuscular deformities are associated with higher new neurologic risks. Very few studies have had the large numbers of pediatric patients with curves exceeding 100 deg to ascertain the new neurologic deficit (NND) rates and recovery patterns as it relates to curve laterality and diagnosis. METHOD: The FOX pediatric database from 17 international sites was queried for New Neurologic Deficit (NND) as characterized by change in American Spinal Injury Association (ASIA) Lower or Upper Extremity Motor Score. Recovery rates at specific intervals were recorded and related to the curve type and etiology. RESULTS: Data of 286 consecutive patients with normal pre-operative neurologic exams were reviewed. There were 160 females vs 125 males with an average age of 14.6 years. NND occurred in 27 patients (9.4%) in the immediate post-operative period. Diagnostic categories included idiopathic scoliosis (3 patients); idiopathic kyphoscoliosis(5 patients); congenital scoliosis (7 patients); congenital kyphoscoliosis (4 patients); congenital kyphosis (6 patients), other kyphosis (1 patient) and syndromic (1 patient). 1 patient was lost to follow-up (f/u) after discharge; 1 had chronic deficits at the first post-operative erect visit (from discharge to 9 months f/u) and was subsequently lost to follow-up; 2 patients were improving at 1-year f/u but lost to subsequent f/u. 16 patients had normal neurologic function by the time of the first post-operative erect visit, 21 patients at 1-year f/u and 21 patients at the 2-year f/u. 2 patients (0.69%) had improved NND at 2-year mark. CONCLUSION: A significant proportion of patients with complex spine deformity experience NND. However, significant improvement in neurologic function can be expected over time as seen in this study without additional surgical intervention in most cases. Congenital deformities accounted for 63% of the patients experiencing NND.

Does thoracoplasty adversely affect lung function in complex pediatric spine deformity? A 2-year follow-up review.

STUDY DESIGN: Retrospective review of prospective multi-center cohort. OBJECTIVE: To investigate the impact of thoracoplasty on pulmonary function at 2-year follow-up among complex pediatric spine deformity patients. Complex pediatric spine deformities may be associated with significant rib prominence causing body image concerns. Surgical correction of spine deformity may include thoracoplasty to correct the rotational prominence. Some surgeons refrain from performing thoracoplasty due to its purported negative effect on pulmonary function. There is paucity of literature on the effect of thoracoplasty on pulmonary function at 2-year follow-up in pediatric patients with complex spine deformity. METHODS: We reviewed data of 312 patients (> 100°, with or without vertebral column resection (VCR)) or (< 100° with VCR)) from an international multicenter database. Data of 106 patients with complete radiographic and pulmonary function test (PFT) assessment with a minimum of 2-year follow-up was analyzed. Paired t test was performed to compare pre-op and 2-year PFT results. PFT comparison was stratified based on thoracoplasty status (thoracoplasty: Group 1 vs. no thoracoplasty: Group 2). RESULTS: 106 patients (61 patients Group 1 vs. 45 in Group 2). The average age and gender ratio were similar in both groups (p > 0.05). Group 1 had significantly lower body mass index (BMI) compared to Group 2 (18.4 kg m-2 ± 2.8 vs. 19.9 kg m-2 ± 4.8, p = 0.0351). The average baseline coronal and sagittal Cobbs were larger for Group 1 relative to Group 2 (p  < 0.05). The distribution of deformity etiology and curve types, and apices were similar between the two groups (p  >  0.05). The rate of pre-op utilization of halo gravity traction (HGT) was 52.5% vs. 26.7% (p  =  0.008), at an average duration of 103 days vs. 47 days, p  =  0.0001. The rate of surgical osteotomies was similar in both groups. Estimated blood volume (EBV) loss was greater in Group 1 (63.1% vs. 43.1%, p  =  0.0012). Post-op coronal and sagittal Cobb correction was similar in both groups. The incidence of post-op pulmonary complication was similar in both groups (8.2% vs. 8.9%, p  =  0.899). Baseline and 2-year follow-up PFT did not differ significantly between and within the groups. Vertebral column resection (VCR) did not negatively affect PFT in both groups. CONCLUSION: Despite higher curve magnitudes in patients undergoing surgical correction and thoracoplasty for complex pediatric spine deformity, our findings revealed that thoracoplasty does not negatively affect pulmonary function at 2-year follow-up.

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.

Relationship of the character of rod fractures on outcomes following long thoracolumbar fusion to the sacrum for adult spinal deformity.

BACKGROUND CONTEXT: Rod fractures (RF) and pseudarthrosis are a frequent occurrence after adult spinal deformity (ASD) surgery and may be problematic. However, not all RF signal nonunion and cause clinical concern. An improved understanding of the sequelae after RF occurrence is valuable for further management. PURPOSE: To characterize the radiographic findings, clinical outcomes, and revision rates between patients who developed unilateral RF (URF) and bilateral RF (BRF) following thoracolumbar posterior spinal fusions to the sacrum for ASD and identify patient characteristics associated with clinically significant RF that lead to subsequent revision surgeries and detection of nonunion. STUDY DESIGN/SETTING: A retrospective single-center cohort study was performed. PATIENT SAMPLE: Patients undergoing long-construct posterior spinal fusions to the sacrum performed at a single institution from 2004 to 2014 and developed a RF postoperatively were included. OUTCOME MEASURES: Patient demographics, radiographic parameters, surgical data, Oswestry Disability Index (ODI), Scoliosis Research Society-22 (SRS-22), and revision rates. METHODS: Inclusion criteria were ASD patients age >18 who had ≥5 vertebrae instrumented and fused posteriorly to the sacrum and development of RF. Data were compared among patients: who developed unilateral-nondisplaced RF (UNRF), unilateral-displaced RF (UDRF), bilateral-nondisplaced RF and bilateral-displaced RF (BDRF) at baseline and follow-up. ODI and SRS-22 scores were assessed at baseline, 1 year postoperatively, the time of RF occurrence, and latest follow-up. RESULTS: Of 526 patients who met inclusion criteria, 96 (18.3%) developed RF (URF n=70 [73%]; BRF n=26 [27%]). Preoperative demographics and surgical parameters were similar between the groups. BRF patients had substantial loss of sagittal correction from 1-year postoperatively to the time of RF, including loss of sagittal vertical axis (4.8 cm vs. 2.2 cm; p<.001), loss of lumbar lordosis (14.8° vs. 4.9°; p=.010) and loss of pelvic incidence minus lumbar lordosis mismatch (PI-LL) mismatch (5.0° vs. 14.6°; p=.020) compared with those of URF patients. The BDRF group had more loss of ODI scores (13.4 vs. 4.2; p=.013), SRS pain score (0.8 vs. 0.2; p=.024), SRS function score (0.3 vs. 0; p=.020) and SRS subscore (0.4 vs. 0.1; p=.148) from 1-year postoperatively to the time of RF and underwent revision surgery more often than the UNRF group (87.5% vs. 4.8%; p<.0001). At final follow-up (median 2.8 years, range 1-10.3 years after RF detection), URF patients who did not undergo revision surgeries still maintained equivalent sagittal alignment correction (sagittal vertical axis, LL and PI-LL; all p>.05) and had similar, not worse, mean ODI scores, SRS Subscore and SRS pain compared with the time at RF and 1-year follow-up. CONCLUSIONS: RF are not uncommon after ASD operations. Asymptomatic, UNRF in our study did not jeopardize clinical outcomes or radiographic alignment parameters and, in most cases, did not represent a nonunion, as opposed to BRF. BRF patients exhibited loss of sagittal correction, loss of clinical outcome improvements, as measured by ODI, SRS pain and SRS Subscore at the time of RF, and were revised more often than URF patients.

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.

Cervical and Cervicothoracic Sagittal Alignment According to Roussouly Thoracolumbar Subtypes.

STUDY DESIGN: Cross-sectional cohort. OBJECTIVE: To determine normative radiographic sagittal cervical alignment in asymptomatic volunteers based on Roussouly thoracolumbar sagittal alignment subtypes. SUMMARY OF BACKGROUND DATA: Comprehension of differences in cervicothoracic alignment with respect to variations in thoracolumbar alignment is limited. METHODS: Asymptomatic adults were recruited and the following parameters measured: PI, PT, SS, LL, orbital tilt, orbital slope, occipital slope and incidence, occiput-C2 lordosis, C2-7 lordosis, occiput-C7 lordosis, CBVA, T1 slope, cervicothoracic alignment, T2-5 kyphosis, and C2-C7 sagittal vertebral alignment (SVA). Each was classified into one of Roussouly's four thoracolumbar subtypes and cervical alignment parameters were compared between groups. RESULTS: Eighty-seven individuals [male-23; female-64; average age 49 ±â€Š16 yr (22-77 yr)] were included for analysis. The four groups were not different by age, sex, and body mass index (BMI). Lumbopelvic parameters (PI, SS, PT, LL) were different between Roussouly types. Average values for all patients included: CBVA (-1 ±â€Š9°), occiput-C2 lordosis (28 ±â€Š9°), occiput-C7 lordosis (39 ±â€Š14°), C2-7 lordosis (11 ±â€Š14°), C2-7 SVA (21 ±â€Š9 mm), T1 slope (25 ±â€Š9°), C6-T4 angle (5 ±â€Š8°), T2-5 angle (16 ±â€Š7°), thoracic kyphosis (47 ±â€Š13°). No sagittal radiographic alignment measurements of the cervical spine and cervicothoracic junction were different between groups, except for the global cervical lordosis (occiput-C7 Cobb), which was found to be lowest for Roussouly type 2 (35 ±â€Š14°) and highest for type 4 (48 ±â€Š14°) (P = 0.01). Mean C2-C7 sagittal Cobb, T2-T5 sagittal Cobb, and T1 slope were not different between groups. CONCLUSIONS: In asymptomatic volunteers, normative sagittal alignment parameters of the cervical spine, cervicothoracic junction, and thoracic spine based on variations in thoracolumbar sagittal alignment, as proposed by Roussouly, are established. These data may guide surgical correction of cervicothoracic deformities to ensure appropriate restoration of normal cervicothoracic parameters to maintain good horizontal gaze and overall sagittal plane alignment. LEVEL OF EVIDENCE: 3.

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.

Rod fracture in adult spinal deformity surgery fused to the sacrum: prevalence, risk factors, and impact on health-related quality of life in 526 patients.

BACKGROUND CONTEXT: Risk factors associated with rod fracture (RF) following adult spinal deformity (ASD) surgery fused to the sacrum remain debatable, and the impact of RF on patient-reported outcomes (PROs) after ASD surgery has not been investigated. PURPOSE: We aimed to evaluate the prevalence of and risk factors for RF and determine PROs changes associated with RF after ASD surgery fused to the sacrum. STUDY DESIGN/SETTING: A retrospective single-center cohort study was performed. PATIENT SAMPLE: Patients undergoing long-construct posterior spinal fusions to the sacrum performed at a single institution by two senior spine surgeons from 2004 to 2014 were included. OUTCOME MEASURES: Patient demographics, radiographic parameters, and surgical factors were assessed for risk factors associated with RF. Oswestry Disability Index (ODI) and Scoliosis Research Society-30 (SRS-30) scores were assessed at baseline, 1 year postoperatively, and latest follow-up. METHODS: Inclusion criteria were ASD patients age >18 who had ≥5 vertebrae instrumented and fused posteriorly to the sacrum and either development of RF or no development of RF with minimum 2-year follow-up. Patient characteristics, operative data, radiographic parameters, and PROs were analyzed at baseline and follow-up. Separate Cox proportional hazard models based on rod material and diameter were used to determine factors associated with RF. RESULTS: Five hundred twenty-six patients (80%) were available for analysis. RF occurred in 97 (18.4%) patients (unilateral RF n=61 [63%]; bilateral RF n=36 [37%]). Risk factors for fracture of 5.5 mm cobalt chromium (CC) instrumentation (CC 5.5 model) included preoperative sagittal vertical axis (hazard ratio [HR] 1.07, 95% confidence interval [95% CI] 1.02-1.14 per 1-cm increase), preoperative thoracolumbar kyphosis (HR 1.02, 95% CI 1.01-1.04 per 1-degree increase), and number of levels fused for patients who received rhBMP-2 <12 mg per level fused (HR 1.48, 95% CI 1.20-1.82 per 1-level increase). Implants that were 5.5-mm CC constructs were at a higher risk for fracture than 6.35-mm stainless steel (SS) constructs (HR 8.49, 95% CI 4.26-16.89). The RF group had less overall improvement in SRS Satisfaction (0.93 vs. 1.32; p=.007) and SRS Self-image domain scores (0.72 vs. 1.02; p=.01). The bilateral RF group had less overall improvement in ODI (8.1 vs. 15.8; p=.02), SRS Subscore (0.51 vs. 0.85; p=.03), and SRS Pain domain scores (0.48 vs. 0.95; p=.02) compared with the non-RF group at final follow-up. CONCLUSIONS: The prevalence of all RF after index procedures was 18.4%, 37% for bilateral RF. Greater preoperative sagittal vertical axis, greater preoperative thoracolumbar kyphosis, increased number of vertebrae fused for patients who received rhBMP-2 <12 mg per level fused, and CC 5.5-mm rod were associated with RF. Less improvement in patient satisfaction and self-image was noted in the RF group. Furthermore, bilateral RF significantly affected PROs as measured by ODI and SRS Subscore at final follow-up.

Variations in Sagittal Alignment Parameters Based on Age: A Prospective Study of Asymptomatic Volunteers Using Full-Body Radiographs.

STUDY DESIGN: Cross-sectional cohort study. OBJECTIVE: Describe age-stratified normative values of traditional and novel sagittal alignment parameters. SUMMARY OF BACKGROUND DATA: Full-body radiographic techniques can capture coronal and sagittal standing images from the occiput to the foot without stitching or vertical distortion. This provides an ideal method to evaluate measures of global alignment. METHODS: Adults with no back or neck symptoms were recruited. Age, body mass index, Neck Disability Index, and Oswestry Disability Index scores were recorded. The following parameters were measured: center sacral vertebral line, Occiput-C2 (O-C2) lordosis, cervical lordosis (C2-C7, CL), thoracic kyphosis (T2-12, TK), T2-T5 kyphosis, T5-T12 kyphosis, thoracolumbar kyphosis (T10-L2), lumbar lordosis (L1-S1, LL), sacral slope, pelvic tilt, pelvic incidence (PI), knee flexion angle, global sagittal angle, T1-pelvis angle, C2-S1 sagittal vertical axis (SVA), C7-S1 SVA, Basion-C7 SVA, B-S1 SVA and Basion to the center of the femoral head SVA and PI minus LL. Comparisons of sagittal alignment parameters between different age groups were performed. A Pearson correlation was used to determine relationships. RESULTS: One hundred fifteen volunteers had imaging suitable for analysis; average age as 50.1 years (range 22-78), average body mass index was 28, average Neck Disability Index was 3.4 ±â€Š4.4, and average Oswestry Disability Index was 1.7 ±â€Š4.9. CL (r = -0.34, P = 0.001), T1-pelvis angle (r = 0.44, P < 0.001), knee flexion angle (r = 0.42, P < 0.001), global sagittal angle (r = 0.56, P < 0.001), and C7 SVA (r = 0.46, P < 0.001) all increased with age. LL decreased with age (r = 0.212, P = 0.039). We were able to establish a chain of correlation extending from the toes to the occiput and report age-based normative values for all parameters. CONCLUSION: We describe age-based normative sagittal alignment parameters in the adult spine with complete visualization from the occiput to the feet. We describe compensatory changes that occur to maintain sagittal balance. These values may be used as a reference for future studies. LEVEL OF EVIDENCE: 4.

Variations in Occipitocervical and Cervicothoracic Alignment Parameters Based on Age: A Prospective Study of Asymptomatic Volunteers Using Full-Body Radiographs.

STUDY DESIGN: Cross-Sectional Cohort Study OBJECTIVE.: To describe age-stratified normative values of novel occipitocervical, cervical, and cervicothoracic alignment parameters. SUMMARY OF BACKGROUND DATA: Full-body radiographic images obtained without stitching or vertical distortion represent an ideal method to evaluate occipitocervical alignment and horizontal gaze. METHODS: One hundred twenty adults with no back or neck symptoms were recruited. Age, sex, body mass index, Neck Disability Index (NDI), and Oswestry Disability Index scores were recorded. Radiographic parameters measured included: center sacral vertebral line, chin brow vertical angle (CBVA), orbital tilt (OrT), orbital slope, occipital slope (OS), occipital incidence, occiput-C2 (O-C2) lordosis, cervical lordosis (C2-C7, CL), T1 slope (TS), neck tilt, thoracic inlet angle (TIA), cervicothoracic kyphosis (C6-T4), and C2-C7 sagittal vertical axis (C2-7 SVA). Interobserver reliability was calculated for all measurements (intraclass correlation coefficient, ICC). A Pearson correlation was used to determine relationships between variables. RESULTS: A total of 115 patients were analyzed; average age as 50.1 years (range 22-78). All measured variables had an ICC >0.6. CL (r = -0.33, P < 0.001), TS (r = 0.42, P < 0.001), TIA (r = 0.24, P = 0.010), and C7 SVA (r = 0.48, P < 0.001) all increased with age. OrT (r = -0.88, P < 0.001) and OS (r = 0.73, P < 0.001) were both strongly correlated with CBVA and each other (r = -0.83, P ≤ 0.001). Both measures were also correlated with the C2-C7 SVA (OrT, r = 0.41, P < 0.001; OS, r = -0.29, P = 0.002) and O-C2 angle (OrT, r = 0.46, P < 0.001; OS, r = -0.28, P = 0.003). C6-T4 angulations was negatively correlated with NDI scores in this population (r = -0.25, P = 0.007). CONCLUSION: We present age-based normative values for occipitocervical, cervicothoracic, and cervical alignment parameters using a novel biplanar radiographic imaging technique. We introduce measures of craniocervical alignment that might provide surgeons with an intuitive way to account for the position of the orbit when planning cervical deformity correction. LEVEL OF EVIDENCE: 4.

Pulmonary function following adult spinal deformity surgery: minimum two-year follow-up.

BACKGROUND: The literature regarding pulmonary function in adult patients with spinal deformity is limited, and the effect of spinal deformity surgery on pulmonary function has not been clearly understood. We hypothesized that adult patients with spinal deformity who had preoperative pulmonary impairment (a percent-predicted value of <65% forced expiratory volume in one second [FEV1] as measured by pulmonary function test) or who were undergoing revision surgery may be at risk for exacerbated decline in pulmonary function. METHODS: Pulmonary function test results were prospectively collected for 164 adult patients with spinal deformity (mean age, 45.9 years) who underwent surgical treatment at a single institution and were followed for a minimum of two years (mean, 2.8 years). One hundred (61%) of the patients underwent primary surgery, and sixty-four (39%) of the patients had revision surgery. For the majority of patients (77%), a posterior-only surgical approach was used. Radiographs for 154 patients were analyzed for major thoracic and sagittal T5-T12 curve magnitude/correction. RESULTS: For all patients, we noted a significant change in major thoracic Cobb angle, from a mean of 47.4° to 24.9°(p < 0.001), and in sagittal Cobb angle, from a mean of 35.5° to 30.0°(p < 0.001), as well as a significant decline in absolute and percent-predicted pulmonary function values, with percent-predicted FEV1 and percent-predicted forced vital capacity (FVC) decreasing 5.3% (p < 0.001) and 5.7% (p < 0.001), respectively. A clinically significant decline (a decline of ≥10% in percent-predicted FEV1) was observed in 27% of the patients. The number of patients with pulmonary impairment increased nonsignificantly from seventeen (10%) preoperatively to twenty-three (14%) after surgery (p = 0.31). Patients with preoperative pulmonary impairment demonstrated a significant improvement in absolute and percent-predicted FEV1 after surgery compared with those without preoperative impairment (2.7% compared with -6.2%; p < 0.001). Patients who underwent revision surgery did not differ from primary surgery patients in terms of postoperative percent-predicted results. However, revision surgery more frequently resulted in a significant decline in pulmonary function (twenty-three patients [36%] compared with twenty-two [22%]; p = 0.05). There was no difference in pulmonary function when comparing surgical approaches (anterior/combined anterior-posterior or posterior-only) or when comparing results by upper-instrumented vertebra (UIV). CONCLUSIONS: We found a significant decline in absolute and percent-predicted results of pulmonary function tests following surgical correction for spinal deformity in adults.

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.

Radiographical and Clinical Outcomes of Posterior Column Osteotomies in Spinal Deformity Correction.

STUDY DESIGN: Prospectively enrolled, retrospectively analyzed case series. OBJECTIVE: To evaluate a large series of pediatric patients/patients with adult spinal deformity undergoing surgery with posterior column osteotomies (PCOs). SUMMARY OF BACKGROUND DATA: Osteotomies of the posterior column (Smith-Petersen or Ponté) are used to reduce kyphosis, increase lordosis, or increase spinal flexibility. However, little focused evidence exists regarding the efficacy and safety of this technique. METHODS: A total of 128 consecutive patients underwent posterior spinal fusion with PCOs with minimum 2-year follow-up. Seventy-five were primary surgical procedures; 53 were revisions. Data were collected from hospital charts, clinic notes, radiographs, and standardized questionnaires (Scoliosis Research Society-30 and Oswestry Disability Index). RESULTS: A total of 128 patients aged 37.6 ± 21 years underwent 518 PCOs (mean, 4.0 ± 2.2 yr) with 14.4 ± 3 mean instrumentation levels, with 3-year (range, 2-6.8 yr) average follow-up. PCOs were used for kyphosis correction in 49%, scoliosis correction at the apex of a curve in 13%, and both in 38%. One hundred six patients had complete radiographical data available for evaluation. Mean kyphosis correction per PCO was 8.8° ± 7.2°, varying with patient age (10.2° for those younger than 21 yr vs. 7.7° for those 21 yr or older, P < 0.0001) and region of the spine: thoracolumbar (T10-L2) 11.6°, lumbar (L2-S1) 9.4°, midthoracic (T6-T10) 7.2° and proximal thoracic (T1-T6) 3.6°. With PCOs at the apex of a curve, the maximum coronal Cobb decreased from 66° ± 21° to 31° ± 14° (P < 0.0001). Average estimated blood loss was 1419 ± 887 mL, correlating with greater age (P < 0.0001) and more instrumented levels (P < 0.0001), but not with the number of PCOs (P = 0.32). Complications occurred in 31 (24.2%) patients, including 4 radiculopathies (none attributable to PCOs). Complications did not correlate with the number of PCOs (P = 0.5). Six (4.7%) patients had loss of spinal cord monitoring or a failed wake-up test that could be attributed to overcorrection with PCOs, but none had postoperative deficits. Oswestry Disability Index scores improved (34.4 ± 17 to 23.6 ± 18, P < 0.0001), as did normalized Scoliosis Research Society-30 scores (63.7 ± 13 to 76.4 ± 15, P < 0.0001). CONCLUSION: Patients in this series undergoing posterior spinal fusion with PCOs achieved overall favorable outcomes for spinal deformity correction. The number of PCOs did not correlate with increased estimated blood loss or complications. The main technical concern was overcorrection, but neurological consequences associated with overcorrection were identified by intraoperative spinal cord monitoring and wake-up tests, and no patients experienced permanent neurological deficits related to PCOs. LEVEL OF EVIDENCE: 4.

Pulmonary function improvement after vertebral column resection for severe spinal deformity.

STUDY DESIGN: Retrospective review of prospectively accrued cohorts. OBJECTIVE: We hypothesized that posterior-only vertebral column resection (PVCR) would result in improved postoperative pulmonary function, avoiding pulmonary insults from combined anterior/posterior approaches. SUMMARY OF BACKGROUND DATA: Pulmonary function after PVCR for severe spinal deformity has not been previously studied. Previous studies have demonstrated impaired pulmonary performance after combined anterior/posterior fusions. METHODS: Serial pulmonary function testing (PFTs) in 49 patients (27 pediatric, 22 adult) who underwent PVCR at a single institution was reviewed. Mean age at surgery was 28.7 years (range, 8-74 yr), and mean follow-up was 32 months (range, 23-64 mo). Thoracic PVCRs (T5-T11) were performed in 31 patients and thoracolumbar PVCRs (T12-L5) in 18 patients. RESULTS: Pediatric patients who underwent PVCR experienced both increased mean forced vital capacity (FVC) (2.10-2.43 L, P = 0.0005) and forced expiratory volume in 1 second (FEV1) (1.71-1.98 L, P = 0.001). There were no significant differences in percent-predicted values for FVC (69%-66%, P = 0.51) or FEV1 (64%-63%, P = 0.77). In adult patients, there were no significant changes in FVC (2.73-2.61 L, P = 0.35) or FEV1 (2.22-2.07 L, P = 0.51) after PVCR; also, changes in adult percent-predicted values for FVC (79%-76%, P = 0.47) and FEV1 (78%-74%, P = 0.40) were not significant. In pediatric patients who underwent PVCR, improved PFTs were correlated with younger age (P = 0.02), diagnosis of angular kyphosis (P ≤ 0.0001), no previous spine surgery (P = 0.04), and preoperative halo-gravity traction (P = 0.02). Comparison of PFT changes between patients who underwent PVCR and a control group who underwent combined anterior/posterior approaches revealed no significant differences. CONCLUSION: In pediatric patients, PVCR resulted in small but significant improvements in postoperative FVC and FEV1. In adult patients, no significant increases in PFTs were found. Patients who have the greatest potential for lung and thoracic cage growth after spinal correction are most likely to have improved pulmonary function after PVCR.

Transforaminal versus anterior lumbar interbody fusion in long deformity constructs: a matched cohort analysis.

STUDY DESIGN: Prospectively enrolled, retrospectively analyzed matched cohort analysis. OBJECTIVE: Evaluate the relative merits of transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) when performed in long deformity constructs. SUMMARY OF BACKGROUND DATA: Interbody fusion is frequently used at the caudal levels of long-segment spinal deformity instrumentation constructs to protect the sacral implants and enhance fusion rates. However, there is a paucity of literature regarding which technique is more efficacious. METHODS: Forty-two patients who underwent TLIF and 42 patients who underwent ALIF were matched with respect to age, sex, comorbidities, curve magnitude, fusion length, and ALIF/TLIF level. Radiographs and clinical outcomes were compared at minimum 2-year follow-up. RESULTS: Age averaged 54.0 years and instrumented vertebrae averaged 13.6. TLIFs had less operative time (481 vs. 595 min, P = 0.0007), but greater blood loss (2011 vs. 1281 mL, P = 0.0002). Overall complications (TLIF, 12/42 vs. ALIF, 15/42) and neurological complications (TLIF, 4/42 vs. ALIF, 3/42) did not differ. One pseudarthrosis occurred at an ALIF level, with none at TLIF levels. Patients who underwent ALIF began with lower SRS scores but showed more improvement (44.4 to 70.7 vs. 58.6 to 70.6, P = 0.0043). ODI scores in both groups improved similarly. Regionally, ALIFs engendered more lordosis than TLIFs at L3-S1 (gain of 6.9° vs. -2.6°, P < 0.0001) but not T12-S1 (gain of 11.5° vs. 7.9°, P = 0.29). Locally, ALIFs created more lordosis at L4-L5 (gain of 5.6° vs. -1.7°, P < 0.0001) and L5-S1 (gain of 2.5° vs. -1.4°, P = 0.022), but not at L3-L4 (gain of 5.3° vs. 4.0°, P = 0.65). Patients who underwent TLIF obtained greater correction of anteroposterior Cobb angles in lumbar (reduction of 22.4° vs. 9.9°, P < 0.0001) and lumbosacral curves (reduction of 10.3° vs. 3.4°, P < 0.0001). CONCLUSION: Spinal deformity surgery used TLIFs rather than ALIFs resulted in shorter operative time with no difference in complication rates. ALIFs provided more segmental lordosis, whereas TLIFs afforded better correction of scoliotic curves.

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.

Major complications and comparison between 3-column osteotomy techniques in 105 consecutive spinal deformity procedures.

STUDY DESIGN: A retrospective review. OBJECTIVE: To characterize the risk factors for the development of major complications in 3-column osteotomies and determine whether the presence of a major complication affects ultimate clinical outcomes. SUMMARY OF BACKGROUND DATA: Three-column spinal osteotomies, including pedicle subtraction osteotomy (PSO) and vertebral column resection (VCR), are common techniques to correct severe and/or rigid spinal deformities. METHODS: Two hundred forty consecutive PSO (n = 156) and VCR (n = 84) procedures in 237 patients were performed at a single institution between 1995 and 2008. Of these, 105 patients (87 PSOs, 18 VCRs) had complete preoperative and minimum 2-year postoperative clinical outcomes data available for analysis. Using established criteria, we reported complications as major or minor and further stratified complications as surgical versus medical and permanent versus transient. Risk factors for complications and their effect on Scoliosis Research Society (SRS) clinical outcomes at baseline and at 2 years or more were assessed. RESULTS: Major medical and surgical complications occurred at similar rates in both PSOs and VCRs (38%, 33 of 87 vs. 22%, 4 of 18; P = 0.28). Overall, 24.8% (26 of 105) experienced major surgical complications (3 permanent) and 15.2% (16 of 105) experienced major medical complications (4 permanent). Patients with PSO were older (53 vs. 29 yr; P < 0.001), had greater estimated blood loss (1867 vs. 1278 mL; P = 0.02), and showed a trend toward fewer fused levels (10.1 vs. 12.2; P = 0.06). Risk factors for major complications included preoperative sagittal imbalance of 40 mm or more (P = 0.01), age 60 years and older (P = 0.01), and the presence of 3 or more medical comorbidities (P = 0.04). Both groups improved significantly from baseline in SRS subscores; however, patients with PSO started off worse but improved more than VCRs in both the pain (+1.0 vs. +0.1; P < 0.001) and function (+0.6 vs. +0.2; P = 0.01) domains, with no differences in final satisfaction (4.1 vs. 4.3; P = 0.54). PSO and VCR patients with no complications had slightly higher satisfaction scores than patients with minor-only complications, major transient complications, and major permanent complications. There were no significant differences among the groups with respect to change in SRS subscores from baseline, and all complication groups improved significantly from baseline (P = 0.04). CONCLUSION: Major complications occurred in 35% of 3-column osteotomies and at similar rates for both PSO (38%) and VCR (22%) procedures. The presence of a major complication did not affect the ultimate clinical outcomes at 2 years or more.