How to determine the optimal proximal fusion level for Scheuermann kyphosis.

OBJECTIVE: To determine optimal proximal fusion levels for instrumented spinal fusion for Scheuermann kyphosis. METHODS: We reviewed 86 patients (33 women) who underwent corrective instrumented spinal fusion for Scheuermann kyphosis. All patients had long-cassette upright lateral radiographs taken preoperatively, postoperatively, and at 2 years and the last follow-up. Demographic, radiographic, and surgical parameters were compared between patients with and without PJK. RESULTS: PJK occurred in 28 patients (32%). The mean maximum Cobb angle was 85.8° ± 11.7° preoperatively, 54.8° ± 14.2° postoperatively, and 59.7° ± 16.8° at the last follow-up. Age and sex did not differ between the PJK and non-PJK groups (P > 0.05). The preoperative curve characteristics, fusion levels, and corrective ratio were similar in both groups (P > 0.05). The maximal Cobb angle at 2 years and the last follow-up significantly differed between the 2 groups (P < 0.05). The proportion of patients with the uppermost instrumented vertebra (UIV) at or above the proximal end vertebra (PEV) was similar in both groups (P > 0.05). The proportion of patients with UIV at or above T2 was significantly greater in the non-PJK group (P < 0.05). PJK was significantly associated with a C7 plumb line (C7PL)-sacrum distance ≥ 50 mm (P < 0.05). CONCLUSION: PJK is the main cause of postoperative correction loss. Proper fusion-level selection can reduce PJK occurrence. We recommend having the UIV at T2 or above, especially when the C7PL-sacrum distance ≥ 50 mm.

Geometric analysis of pedicle subtraction osteotomy (PSO) for Kyphosis correction: anterior lengthening may occur at the osteotomized body as well as at the discs above and below.

OBJECTIVE: To validate the authors kyphosis correction formula for pedicle subtraction osteotomy (PSO) cases. Additionally, to use the formula to evaluate the safety of PSO by determining if there is anterior lengthening. METHODS: Twenty-two patients with primarily kyphosis corrected by PSO and with clear landmarks on preoperative and postoperative x-rays were selected. Several anatomical lines and angle measurements were utilized as depicted previously in the Vertebral Column Resection formula (see below). Two approximations were calculated: the geometric approximation (G) = (tanG°*2 + 1)*15° and the rough approximation (R) which is about the same amount of actual shortening (x), if parallel length (y) ≥ 40; twice of x, if y < 40. For each patient, the change of segmental kyphosis angle (K°) was measured and compared with G° and R°, and the correlation between each value was analyzed. RESULTS: The absolute Mean ± SE for K - G and K - R was 2.33° ± 0.34 and 6.09° ± 0.58, respectively. K - G is < 3° (p = 0.03). K - R is < 8° (p = 0.001). In other words, K was close to G and R and thus can be predicted by these approximations. Average posterior shortening, anterior shortening, and kyphosis correction at each level were 20.8 ± 2.0 mm, - 3.64 ± 1.5 mm (which equates to anterior lengthening), and 31.05° ± 2.0, respectively. Anterior lengthening occurred in 13 cases (in 4 cases, both at the body as well as at the disc above and below.) The correlation between posterior and anterior shortening was 0.03 (p = 0.88). There were 3 cage insertion cases: 1 had anterior lengthening, while 2 had anterior shortening even with the cage. CONCLUSION: This study validated the geometric and rough approximations originally used in PVCR patients, for PSO patients. Additionally, this study found that anterior lengthening may occur in PSOs usually at the discs, but occasionally at the osteotomized body.

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.

Deformity Angular Ratio Describes the Severity of Spinal Deformity and Predicts the Risk of Neurologic Deficit in Posterior Vertebral Column Resection Surgery.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To assess the value of the deformity angular ratio (DAR, maximum Cobb measurement divided by number of vertebrae involved) in evaluating the severity of spinal deformity, and predicting the risk of neurologic deficit in posterior vertebral column resection (PVCR). SUMMARY OF BACKGROUND DATA: Although the literature has demonstrated that PVCR in spinal deformity patients has achieved excellent outcomes, it is still high risk neurologically. This study, to our knowledge, is the largest series of PVCR patients from a single center, evaluating deformity severity, and potential neurologic deficit risk. METHODS: A total of 202 consecutive pediatric and adult patients undergoing PVCRs from November 2002 to September 2014 were reviewed. The DAR (coronal DAR, sagittal DAR, and total DAR) was used to evaluate the complexity of the deformity. RESULTS: The incidence of spinal cord monitoring (SCM) events was 20.5%. Eight patients (4.0%) had new neurologic deficits. Patients with a high total DAR (≥25) were significantly younger (20.3 vs. 29.0 yr, P = 0.001), had more severe coronal and sagittal deformities, were more myelopathic (33.3% vs. 11.7%, P = 0.000), needed larger vertebral resections (1.8 vs. 1.3, P = 0.000), and had a significantly higher rate of SCM events than seen in the low total DAR (<25) patients (41.1% vs. 10.8%; P = 0.000). Patients with a high sagittal DAR (≥15) also had a significantly higher rate of SCM events (34.0% vs. 15.1%, P = 0.005) and a greater chance of neurologic deficits postoperatively (12.5% vs. 0, P = 0.000). CONCLUSION: For patients undergoing a PVCR, the DAR can be used to quantify the angularity of the spinal deformity, which is strongly correlated to the risk of neurologic deficits. Patients with a total DAR greater than or equal to 25 or sagittal DAR greater than or equal to 15 are at much higher risk for intraoperative SCM events and new neurologic deficits. LEVEL OF EVIDENCE: 3.

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.

Comparison of Anteroposterior to Posterior-Only Correction of Scheuermann's Kyphosis: A Matched-Pair Radiographic Analysis of 92 Patients.

STUDY DESIGN: Retrospective radiographic benchmark study. OBJECTIVE: To evaluate the amount of instrumented correction obtained from a combined anterior/posterior (A/P) versus posterior-only (post-only) approach for Scheuermann's kyphosis. SUMMARY OF BACKGROUND DATA: An A/P approach was thought to optimize correction; however, instrumentation advances using pedicle screws allow treatment through an all-posterior approach. METHODS: A total of 166 Scheuermann's kyphosis patients were treated between 2 centers: 90 by combined A/P approach at 1 center and 76 by post-only at the second center. From the 166 patients, a matched cohort of 92 (46 from each) was established according to preoperative sagittal (±10°) and hyperextension (HE) Cobb (±10°) measurements and matched for age and gender. RESULTS: In the matched-pair group, average preoperative sagittal Cobb angles were 75.9° for the A/P group versus 78.8° for the post-only group (p = .2). The HE Cobb angles were similar (52.4° vs. 51.1°; p = .6). They showed similar corrections (33.7° vs. 30.6°; p = .3) and postoperative Cobb measurements (43.4° vs. 47.1°; p = .2) as well. The number of fusion levels was 9 in the A/P group and 12 in the post-only group; the difference yielded significance (p = .02). CONCLUSIONS: The A/P and post-only approaches averaged similar degrees of correction. The A/P patients were likely to correct more than their preoperative HE sagittal Cobb measurement, whereas the post-only group corrected close to their preoperative HE measurement. The number of fusion levels was larger with the post-only group.

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.

Can Intraoperative Spinal Cord Monitoring Reliably Help Prevent Paraplegia During Posterior Vertebral Column Resection Surgery?

STUDY DESIGN: Retrospective case series. OBJECTIVE: Analyze patients who underwent posterior vertebral column resection (PVCR) above the conus medullaris with intraoperative spinal cord monitoring (SCM) data loss. SUMMARY OF BACKGROUND DATA: PVCR is a powerful technique for treating severe spinal deformity but carries a high risk for major spinal cord deficits. METHODS: We assessed clinical, radiographic, and electrophysiologic monitoring and operative records of 90 consecutive adult and pediatric patients (mean age, 24.8 years; range, 7.5-76.8) who underwent PVCR above the conus medullaris for severe spinal deformity performed from 2002 to 2010 by one surgeon at one institution. RESULTS: Fifteen of 90 patients (16.7%) (10 male/5 female; mean age, 15 years) lost SCM (n = 13) or had data degradation meeting warning criteria (n = 2). Diagnoses were kyphoscoliosis (n = 8), angular kyphosis (n = 3), global kyphosis (n = 2), and severe scoliosis (n = 2). Seven were revisions. The average pre-/postoperative scolioses were 99° (range, 32°-152°) and 43° (range, 6°-76°), respectively. The average pre-/postoperative kyphoses were +100° (range, 60°-170°) and +54° (range, 28°-100°), respectively. SCM fluctuated during osteotomy on nine occasions, stabilizing with elevation of blood pressure in addition to anterior spinal cord decompression in four, correction of subluxation in one, and traction reduction in one. Seven patients had SCM changes during rod compression. Three required partial release of correction, two larger cage insertion, one subluxation correction, and one pedicle screw removal. One experienced changes during rod placement/removal, and another, as a result of hypothermia. Data returned in all after prompt intervention (mean, 10.1 minutes; range, 1-60) and all awoke with intact lower extremity function. CONCLUSION: The prevalence of SCM changes during PVCR above the conus medullaris was 16.7%, mostly during osteotomy and rod/screw compression. Data returned with prompt intervention and all had intact lower extremity motor function postoperatively. These SCM "saves" strongly emphasize the importance of multimodality neurophysiologic monitoring during high-risk cases, minimizing postoperative complications.

Progressive Myelopathy Patients Who Lack Spinal Cord Monitoring Data Have the Highest Rate of Spinal Cord Deficits Following Posterior Vertebral Column Resection Surgery.

OBJECTIVES: The authors analyzed patients who underwent posterior vertebral column resection (PVCR). All patients had spinal cord monitoring (SCM) attempted but some did not have predictable and usable tracings. SUMMARY OF BACKGROUND DATA: Posterior vertebral column resection is a powerful technique to correct severe spinal deformities but it has the potential for major neurologic complications. Spinal cord monitoring is extremely helpful in managing these difficult patients. METHODS: Spinal cord monitoring data, operative reports, charts, and radiographs of 112 consecutive adult and pediatric patients (mean age, 23.5 years; range, 5.8-74.0 years) who underwent PVCR were reviewed. All surgical procedures were performed between 2002 and 2010 by 1 surgeon at a single institution. RESULTS: Twenty patients (11 male, 9 female; mean age, 15.9 years) of 112 (17.9%) did not have detectable SCM tracings during surgery. Average preoperative and postoperative scoliosis for these 20 patients was 79.2° and 41.3°, respectively. Average preoperative and postoperative kyphosis was 106.6° and 59.8°, respectively. Thirteen of the 20 were revisions. Preoperative neurologic status included acute progressive myelopathy (n = 9), no lower extremity function (n = 6), chronic weak lower extremities (n = 2), chronic quadriparesis (n = 1), and normal (n = 2). Four of 9 patients with acute progressive myelopathy developed transient paraplegia postoperatively. They had angular kyphosis (mean, 116.3°) and 3 were revisions. Compared with the 92 patients who had obtainable intraoperative SCM and no spinal cord deficits, the risk of developing postoperative paraplegia in patients who had no SCM tracings was statistically higher (p = .0008). All 4 with spinal cord deficits after surgery regained varying degrees of lower extremity function and resumed ambulatory status at most recent follow-up. CONCLUSIONS: The prevalence of unobtainable intraoperative SCM during PVCR was 17.9% (20 of 112). Postoperative transient paraplegia occurred exclusively in patients with no monitorable data as a result of angular kyphosis with acute progressive myelopathy. The rate of transient spinal cord deficits was significantly higher when there was no obtainable SCM (4 of 20 vs. 0 of 92 with SCM; p = .0008).

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.

Risk factors for and assessment of symptomatic pseudarthrosis after lumbar pedicle subtraction osteotomy in adult spinal deformity.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To assess the prevalence, risk factors, and clinical outcomes for pseudarthrosis after a lumbar pedicle subtraction osteotomy (PSO). SUMMARY OF BACKGROUND DATA: There exists no large series that examines pseudarthrosis rates of PSOs. METHODS: Data of 171 consecutive patients with adult deformity who underwent a lumbar PSO by 2 surgeons at a single institution with a minimum 2-year follow-up were analyzed. Pseudarthrosis diagnosed through sagittal malalignment and instrumentation failure noted on radiograph was confirmed intraoperatively. RESULTS: Eighteen (10.5%) of 171 patients developed pseudarthrosis after a PSO. Eleven of the 18 patients (6.4% of all patients, 61.1% of the 18 patients with pseudarthrosis) had pseudarthrosis at the PSO site, L3 being the most common; other locations included the lumbosacral junction (4/18), thoracolumbar junction (2/18), and upper thoracic spine (1/18). Preoperative pseudarthrosis level was a predictor of the postoperative level of pseudarthrosis (93%). Fifteen of the 18 patients (83%) had no interbody fusion directly above or below the PSO site, 16 (88%) had a history of pseudarthrosis at the time of PSO surgery and 2 of 3 patients who had prior radiation to the lumbar region developed pseudarthrosis. Most pseudarthroses occurred within the first 2 years (n = 13/18), between 2 and 5 years (n = 3/18), and more than 5 years (n = 2/18) postoperatively. Prior pseudarthrosis (P < 0.0001), pseudarthrosis at the PSO site (P < 0.0001), prior decompression in the lumbar region (P = 0.0037), prior radiation to the lumbar region (P < 0.0001), and presence of inflammatory/neurological disorders (P < 0.0036) were identified as risk factors. All 18 patients with pseudarthroses required revision surgery (posterior-only surgery, n = 12; anteroposterior surgery, n = 6) due to loss of sagittal alignment and pain. The mean pre-revision Scoliosis Research Society score was 85, post-revision score was 95 (P = 0.0166), and the mean pre-revision Oswestry Disability Index score was 42.5, post-revision score was 34.5 (P = 0.0203). CONCLUSION: The overall prevalence of pseudarthrosis was 10.5% of which 61% occurred at the actual PSO site and Scoliosis Research Society and Oswestry Disability Index scores improved significantly after pseudarthrosis repair. LEVEL OF EVIDENCE: 4.

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.

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.

Does preoperative narcotic use adversely affect outcomes and complications after spinal deformity surgery? A comparison of nonnarcotic- with narcotic-using groups.

BACKGROUND CONTEXT: The role of preoperative (preop) narcotic use and its influence on outcomes after spinal deformity surgery are unknown. It is important to determine which patient factors and comorbidities can affect the success of spinal deformity surgery, a challenging surgery with high rates of complications at baseline. PURPOSE: To evaluate if preop narcotic use persists after spinal deformity surgery and whether the outcomes are adversely affected by preop narcotic use. STUDY DESIGN/SETTING: Retrospective evaluation of prospectively collected data. PATIENT SAMPLE: Two hundred fifty-three adult patients (230 females/23 males) undergoing primary spinal deformity surgery were enrolled from 2000 to 2009. OUTCOME MEASURES: Preoperative and postoperative (postop) narcotic use and changes in Oswestry Disability Index (ODI), Scoliosis Research Society (SRS) pain, and SRS total scores. METHODS: Preoperative, 2-year postop, and latest follow-up pain medication use were collected along with ODI, SRS pain, and SRS scores. Preoperative insurance status, surgical and hospitalization demographics, and complications were collected. All patients had a minimum 2-year follow-up (average 47.4 months). RESULTS: One hundred sixty-eight nonnarcotic (NoNarc) patients were taking no pain meds or only nonsteroidal anti-inflammatories preoperatively. Eighty-five patients were taking mild/moderate/heavy narcotics before surgery. The average age was 48.2 years for the NoNarc group versus 53.6 years for the Narc group (p<.005). There were significantly more patients with degenerative than adult scoliosis in the Narc group (47 vs. 28, p<.001; mild 19 vs. 24, p<.02; moderate 6 vs. 14, p<.0003; heavy 3 vs. 10, p<.0002). Insurance status (private/Medicare/Medicaid) was similar between the groups (p=.39). At latest follow-up, 137/156 (88%) prior NoNarc patients were still not taking narcotics whereas 48/79 (61%) prior narcotic patients were now off narcotics (p<.001). Significant postop improvements were seen in Narc versus NoNarc groups with regard to ODI (26-15 vs. 44-30.3, p<.001), SRS pain (3.36-3.9 vs. 2.3-3.38, p<.001), and overall SRS outcome (3.36-4 vs. 2.78-3.68, p<.001) scores. A comparison of change in outcome scores between the two groups showed a higher improvement in SRS pain scores for the Narc versus NoNarc group (p<.001). CONCLUSIONS: In adults with degenerative scoliosis taking narcotics a significant decrease in pain medication use was noted after surgery. All outcome scores significantly improved postop in both groups. However, the Narc group had significantly greater improvements in SRS pain scores versus the NoNarc group.

The prevalence of abnormal preoperative neurological examination in Scheuermann kyphosis: correlation with X-ray, magnetic resonance imaging, and surgical outcome.

STUDY DESIGN: Retrospective. OBJECTIVE: The purpose of this study was to report the prevalence of abnormal neurological findings detected by physical examination in Scheuermann kyphosis and to correlate it to radiographs, magnetic resonance imaging (MRI) findings, and results of operative treatment. SUMMARY OF BACKGROUND DATA: There have been sporadic reports about abnormal neurological findings in patients with Scheuermann kyphosis. METHODS: Among 82 patients with Scheuermann kyphosis who underwent corrective surgery, 69 primary cases were selected. Patients' charts were reviewed retrospectively in terms of pre and postoperative neurological examinations. Sensory or motor change was defined as an abnormal neurological examination. Their duration, associated problems, and various parameters on preoperative radiographs and MRI examinations were also measured to search for any atypical findings associated with an abnormal neurological examination. RESULTS: There were 6 cases (9%) (group AbN), with an abnormal neurological examination ranging from severe myelopathy to a subtle change (e.g., sensory paresthesias on trunk). Five patients recovered to a normal neurological examination after corrective surgery. The remaining 1 patient with severe myelopathy also showed marked improvement and was ambulatory unassisted by 2-year follow-up. In patients with a normal neurological examination (group N, n = 63), only 1 patient had neurological sequelae because of anterior spinal artery syndrome after combined anterior-posterior correction. No preoperative radiographical parameters were significantly different between groups. Average age was 21.3 (AbN) and 18.6 (N) years (P = 0.55). Average preoperative T5-12 kyphosis was 69.0° (AbN) and 72.5° (N) (P = 0.61). Forty-two magnetic resonance images were obtained and all showed typical findings of Scheuermann kyphosis. Five patients in the AbN group (1 patient underwent computed tomography/myelography) and 37 patients in the N group underwent an MRI. CONCLUSION: The prevalence of abnormal neurological findings in Scheuermann kyphosis was 9%, emphasizing the importance of performing a detailed preoperative neurological examination. If congenital stenosis or a herniated thoracic disc is present, myelopathy can occur. No radiographical findings correlated with the abnormal preoperative neurological examinations. A normal MRI can exist in the face of an abnormal neurological examination, and conversely, a normal neurological examination can be seen with an abnormal MRI. Surgery was successful in alleviating abnormal neurological issues. LEVEL OF EVIDENCE: 4.

Does correction of preoperative coronal imbalance make a difference in outcomes of adult patients with deformity?

STUDY DESIGN: Retrospective study with prospectively collected outcomes data. OBJECTIVE: Determine the significance of coronal balance on spinal deformity surgery outcomes. SUMMARY OF BACKGROUND DATA: Sagittal balance has been confirmed as an important radiographic parameter correlating with adult deformity treatment outcomes. The significance of coronal balance on functional outcomes is less clear. METHODS: Eighty-five patients with more than 4 cm of coronal imbalance who underwent reconstructive spinal surgery were evaluated to determine the significance of coronal balance on functional outcomes as measured with the Oswestry Disability Index (ODI) and Scoliosis Research Society outcomes questionnaires. Sixty-two patients had combined coronal (>4 cm) and sagittal imbalance (>5 cm), while 23 patients had coronal imbalance alone. RESULTS: Postoperatively, 85% of patients demonstrated improved coronal balance. The mean improvement in the coronal C7 plumb line was 26 mm for a mean correction of 42%. The mean preoperative sagittal C7 plumb line in patients with combined coronal and sagittal imbalance was 118 mm (range, 50-310 mm) and improved to a mean 49 mm. The mean preoperative and postoperative ODI scores were 42 (range, 0-90) and 27 (range, 0-78), for a mean improvement of 15 (36%) (P = 0.00001; 95% CI, 12-20). The mean Scoliosis Research Society scores improved by 17 points (29%) (P = 0.00). Younger age (P = 0.008) and improvement in sagittal balance (P = 0.014) were positive predictors for improved ODI scores. Improvement in sagittal balance (P = 0.010) was a positive predictor for improved Scoliosis Research Society scores. In patients with combined coronal and sagittal imbalance, improvement in sagittal balance was the most significant predictor for improved ODI scores (P = 0.009). In patients with preoperative coronal imbalance alone, improvement in coronal balance trended toward, but was not a significant predictor for improved ODI (P = 0.092). CONCLUSION: Sagittal balance improvement is the strongest predictor of improved outcomes in patients with combined coronal and sagittal imbalance. In patients with coronal imbalance alone, improvement in coronal balance was not a factor for predicting improved functional outcomes.

Comparison of TLIF with rhBMP-2 versus no TLIF and higher posterolateral rhBMP-2 dose at L5-S1 for long fusions to the sacrum with sacropelvic fixation in patients with primary adult deformity.

STUDY DESIGN: Comparvative case series. Data was prospectively entered and retrospectively analyzed. OBJECTIVE: To evaluate the need for distal lumbar interbody fusion when sufficient recombinant human bone morphogenetic protein-2 (rhBMP-2) is used posterolaterally at L5-S1 in long spinal constructs for adult deformity via costs and radiographical and patient-reported outcome comparisons. SUMMARY OF BACKGROUND DATA: Many authors and investigators have suggested that an interbody fusion is mandatory at L5-S1 with long fusion to the sacrum with sacropelvic fixation. Past studies have shown competitive fusion rates using rhBMP-2 versus iliac crest bone graft for long fusions. There are various advocates for anterior lumbar interbody fusion versus posterior lumbar interbody fusion versus transforaminal lumbar interbody fusion (TLIF). The optimal strategy remains elusive. METHODS: Fifty-seven patients were studied at one institution. Thirty-one patients had no interbody fusion (NI group) with 20 mg of rhBMP-2 posterolaterally on 10 mL of carrier and 26 patients had TLIF at L5-S1 (TLIF group) with 6 mg of rhBMP-2 in the interbody space along with local bone graft and 6 mg of rhBMP-2 on carrier posterolaterally at L5-S1. Patients were followed for 24 to 87 months (mean follow-up, 3.92 yr). Demographics of the 2 groups were similar. RESULTS: There were no detected nonunions at L5-S1 in either group. By our limited cost analysis, the expense of performing a TLIF at L5-S1 is higher than that of using extra rhBMP-2 posterolaterally at that segment. Improvement in outcomes scores, namely Scoliosis Research Society-22 and Oswestry Disability Index, were the same statistically in both groups. Blood loss was greater in the TLIF group than the NI group. There were no identified rhBMP-2 adverse events in either group. CONCLUSION: Utilization of 20 mg of rhBMP-2 at L5-S1 has the potential to be less expensive than an interbody fusion in most patients having a primary long fusion for adult spinal deformity. The apparent fusion rates at L5-S1 were identical in both groups. Both strategies were successful in regard to improving patient outcomes and achieving apparent solid arthrodesis at the lumbosacral junction, which was the focus of this study. LEVEL OF EVIDENCE: 2.

Matched Cohort Analysis of Posterior-Only Vertebral Column Resection Versus Combined Anterior/Posterior Vertebrectomy for Severe Spinal Deformity.

STUDY DESIGN: Retrospective matched cohort analysis. SUMMARY OF BACKGROUND DATA: Posterior-only vertebral column resection (P-VCR) is a potential alternative to combined anterior/posterior vertebrectomy (A-P/VCR) for the treatment of severe spinal deformity. OBJECTIVE: To examine a matched cohort of adult and pediatric patients with severe spinal deformity treated with A/P-VCR versus P-VCR. METHODS: Databases of 2 spine surgeons at 1 institution from 1994 to 2007 were reviewed. Patients were matched based on age at surgery (within 10 years), diagnosis, curve pattern, vertebrae resected (within 1), levels of vertebrae resected (within 2), levels fused (within 5), and minimum 2-year follow-up. A total of 34 P-VCR patients were identified who appropriately matched 34 A/P-VCR patients. The etiology of the deformity and type of curve were matched directly so that they were identical for each matched pair. The remainder of the inclusion parameters was matched as closely as possible between the 2 groups according to the criteria listed above. RESULTS: Final coronal Cobb correction P-VCR versus A/P-VCR showed that 52.6% versus 53.9% (p = .8) was similar, whereas P-VCR final sagittal Cobb correction was superior: 53.0% versus 40.0% (p = .017). The P-VCR group had a significantly shorter total operative time (p = .002) and total length of stay (p = .003). Complications rates were similar and relatively infrequent for both P-VCR and A/P-VCR, including wound infections requiring operative intervention, subsequent revision surgery, and transient motor deficits. Total Scoliosis Research Society scores improved from preoperative to final follow-up for both P-VCR (p = .007) and A/P-VCR (p = .07) groups. CONCLUSIONS: Posterior-only vertebral column resection is a challenging yet safe and effective means of treating severe scoliosis and/or kyphosis. Compared with an A/P-VCR for severe spinal deformity, P-VCR demonstrated shorter operative time and hospital stay, as well as improved sagittal correction and Scoliosis Research Society scores.

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.