Brenda A. Sides

Comparative analysis of pedicle screw versus hook instrumentation in posterior spinal fusion of adolescent idiopathic scoliosis.

Study Design. A retrospective matched cohort study. Objective. To comprehensively compare the 2-year postoperative results of posterior correction and fusion with segmental pedicle screw instrumentation versus with hybrid (proximal hooks and distal pedicle screws) constructs in adolescent idiopathic scoliosis (AIS) treated at a single institution. Summary of Background Data. Despite the reports of satisfactory correction and maintenance of scoliotic curves by pedicle screw instrumentation, there have been no reports on the comprehensive comparison of AIS treatment after segmental pedicle screw instrumentation versus hybrid instrumentation. Materials and Methods. A total of 58 AIS patients that underwent posterior fusion with hybrid instrumentation (29) or pedicle screw (29) instrumentation at a single institution were sorted and matched according to four criteria: similar patient age, fusion levels, identical Lenke curve type, and identical operative methods. Patients were compared at 2-year follow-up according to radiographic changes, operative time, intraoperative blood loss, pulmonary function tests, and SRS-24 outcome scores. Results. The two cohorts were well matched. The preoperative major Cobb angle averaged 62° in the screw group and 60° in the hybrid group. Average major curve correction was 70% in the screw group and 56% in the hybrid group (P = 0.001). At 2-year follow-up, major curve correction was 65% and 46%, respectively (P < 0.001). At 2-year follow-up, thoracic sagittal Cobb angle changes between T5 and T12 were 9.0° decrease in the screw group and 2.4° decrease in the hybrid group compared with preoperative (P = 0.024). There were no differences in the lowest instrumented vertebra below the lower end vertebra (P = 0.56), operative time (P = 0.14), and average estimated blood loss (P = 0.54). Two years following surgery, the screw group demonstrated improved percent predicted pulmonary function values compared with that of the hybrid group (FVC; 81% → 81% in screw group vs. 85% → 79% in hybrid group P = 0.08, FEV1; 73% → 79% in screw group vs. 79% → 75% in hybrid group, P = 0.006). Postoperative total SRS-24 scores were similar in both groups (hybrid group: 99 vs. screw group: 95) (P = 0.19). There were no neurologic complications related to hybrid or pedicle screw instrumentation. Conclusion. Pedicle screw instrumentation offers a significantly better major curve correction and postoperative pulmonary function values without neurologic problems compared with hybrid constructs. Both instrumentation methods offer similar junctional change, lowest instrumented vertebra, operative time, and postoperative SRS-24 outcome scores in the operative treatment of AIS.

Posterior Vertebral Column Resection for Severe Pediatric Deformity : Minimum Two-Year Follow-up of Thirty-Five Consecutive Patients

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

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.

Surgical Revision Rates of Hooks versus Hybrid versus Screws versus Combined Anteroposterior Spinal Fusion for Adolescent Idiopathic Scoliosis

Study Design. Multi-institution retrospective review. Objective. To determine the surgical revision rates of hook, hybrid, anteroposterior, and total pedicle screw constructs for adolescent idiopathic scoliosis (AIS). Summary of Background Data. Much debate continues on the safety, efficacy, and cost of thoracic pedicle screws. Nonetheless, there are no large series that have evaluated the revision rate of various constructs in AIS to determine the need for repeat surgery, and therefore, the added indirect costs and risks of additional procedures. Methods. We retrospectively reviewed the surgical case logs of 1428 patients with AIS at 2 institutions from 1990 to 2004, and the clinical records and radiographs of revision cases. Patients were classified into 1 of 4 groups: hook, hybrid hook and screw, all pedicle screw, and combined anteroposterior fusion constructs. Overall, there were 65 (4.6%) returns to the operating room, or 55 (3.9%) cases after excluding infections without concomitant pseudarthrosis. Results. Of the 65 revision cases, there were 52 females and 13 males, at an average age at first surgery of 13.9 years (range, 9–18 years), and an average age at revision of 14.7 years (range, 12–23 years). For the revision cases, the average initial Cobb was 61.9° (range 44°–110°), and this was not statistically different within the cohorts (P > 0.05). In terms of revision rate, all hook constructs had a higher revision rate secondary to instrumentation failure when compared with screws, while both hook and hybrid constructs had an overall higher surgical revision rate when compared with screw constructs or anteroposterior constructs (all P ≤ 0.05). The pseudarthrosis rate trended toward, but did not meet, statistical significance between these same groups. Conclusion. All pedicle screw and anteroposterior constructs have a lower surgical revision rate when compared with hook and hybrid constructs. The hidden patient and financial costs of these findings should be considered when evaluating overall instrumentation efficacy.

Revision rates following primary adult spinal deformity surgery: six hundred forty-three consecutive patients followed-up to twenty-two years postoperative.

Study Design. Retrospective study. Objective. To analyze the prevalence of and reasons for unanticipated revision surgery in an adult spinal deformity population treated at one institution. Summary of Background Data. No recent studies exist that analyze the rate or reason for unanticipated revision surgery for adult spinal deformity patients over a long period. Methods. All patients presenting for primary instrumented spinal fusion with a diagnosis of adult deformity at a single institution from 1985 to 2008 were reviewed using a prospectively acquired database. All surgical patients with instrumented fusion of ≥5 levels using hooks, hybrid, or screw-only constructs were identified. Patient charts and radiographs were reviewed to provide information as to the indication for initial and any subsequent reoperation. A total of 643 patients underwent primary instrumented fusion for a diagnosis of adult idiopathic scoliosis (n = 432), de novo degenerative scoliosis (n = 104), adult kyphotic disease (n = 63), or neuromuscular scoliosis (n = 45). The mean age was 37.9 years (range, 18–84). Mean follow-up for the entire cohort was 4.7 years, and 8.2 years for the subset of the cohort requiring reoperation (range, 1 month–22.3 years). Results. A total of 58 of 643 patients (9.0%) underwent at least one revision surgery and 15 of 643 (2.3%) had more than one revision (mean 1.3; range, 1–3). The mean time to the first revision was 4.0 years (range, 1 week–19.7 years). The most common reasons for revision were pseudarthrosis (24/643 = 3.7%; 24/58 = 41.4%), curve progression (13/643 = 2.0%; 13/58 = 20.7%), infection (9/643 = 1.4%; 9/58 = 15.5%), and painful/prominent implants (4/643 = 0.6%; 4/58 = 6.9%). Uncommon reasons consisted of adjacent segment degeneration (3), implant failure (3), neurologic deficit (1), and coronal imbalance (1). Revision rates over the follow-up period were: 0 to 2 years (26/58 = 44.8%), 2 to 5 years (17/58 = 29.3%), 5 to 10 years (7/58 = 12.1%), >10 years (8/58 = 13.8%). Conclusion. Repeat surgical intervention following definitive spinal instrumented fusion for primary adult deformity performed at a single institution demonstrated a relatively low rate of 9.0%. The most common reasons for revision were predictable and included pseudarthrosis, proximal or distal curve progression, and infection.

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

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

Pedicle Screw Instrumentation for Adult Idiopathic Scoliosis : An Improvement Over Hook/Hybrid Fixation

Study Design. A matched cohort comparison of adult idiopathic scoliosis (AdIS) patients treated with all pedicle screw constructs compared to hook/hybrid constructs. Objective. To compare clinical and radiographic results of AdIS treatment using all pedicle screw constructs versus hook/hybrid constructs. Summary of Background Data. Pedicle screw instrumentation has demonstrated excellent clinical efficacy in the treatment of pediatric spinal deformity. No prior reports have compared the outcomes of pedicle screw only constructs to hook/hybrid constructs in the treatment of AdIS. Methods. We analyzed 34 consecutive patients undergoing posterior-only correction for AdIS, using pedicle screw instrumentation at minimum 2-year follow-up. Thirty-four matching patients (11 with anterior releases) were selected from a cohort of 58 patients treated with hook/hybrid constructs based on similar age, curve type, magnitude, and fusion levels. Results. Significantly greater curve correction was seen in the pedicle screw compared to the hook/hybrid group (56 vs. 40%, P < 0.01). Coronal and sagittal imbalance were equivalent between the groups (P = 0.91 and 0.23, respectively). Thoracic kyphosis (T5–T12) was maintained in the pedicle screw patients but significantly increased in the hybrid/hook patients over time (P < 0.05). Scoliosis Research Society outcome scores significantly improved in both groups. Blood loss was equivalent but operative time was longer in the hook/hybrid patients. No pedicle screw patients were revised for instrumentation complications with 1 lumbosacral nonunion revised at 5 years postoperative (3% revision rate). Eight of 58 patients among the hook/hybrid cohort underwent 9 revisions for instrumentation failure (n = 3) or nonunion (n = 6) (14% revision rate; P = 0.04). Conclusion. Pedicle screw correction of AdIS is safe and effective. Compared to hook/hybrid constructs, these patients displayed significantly improved correction of the major curve (even in the absence of anterior releases), maintenance of thoracic kyphosis, and a lower revision rate. Similar SRS scores and blood loss were noted. The hook/hybrid patients had significantly longer operative times. The use of BMP-2 in 7 patients and TLIF/ALIF also in 7 of the pedicle screw patients may have decreased the need for revision surgery up to the latest follow-up.

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.

Prospective Pulmonary Function Comparison of Open Versus Endoscopic Anterior Fusion Combined With Posterior Fusion in Adolescent Idiopathic Scoliosis

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

Comparison of surgical treatment in Lenke 5C adolescent idiopathic scoliosis: anterior dual rod versus posterior pedicle fixation surgery: a comparison of two practices.

Study Design. Multicenter analysis of 2 groups of patients surgically treated for Lenke 5C adolescent idiopathic scoliosis (AIS). Objective. Compare patients with Lenke 5C scoliosis surgically treated with anterior spinal fusion with dual rod instrumentation and anterior column support with patients surgically treated with posterior release and pedicle screw instrumentation. Summary of Background Data. Treatment of single, structural, lumbar, and thoracolumbar curves in patients with AIS has been the subject of some debate. Advocates of the anterior approach assert that their technique spares posterior musculature and may save distal fusion levels, and that with dual rods and anterior column support the issues with nonunion and kyphosis have been obviated. Advocates of the posterior approach assert that with the change to posterior pedicle screw based instrumentation that correction and levels are equivalent, and the posterior approach avoids the issues with nonunion and kyphosis. This report directly compares the results of posterior versus anterior instrumented fusions in the operative treatment of adolescent idiopathic Lenke 5C curves. Methods. We analyzed 62 patients with Lenke 5C based on radiographic and clinical data at 2 institutions: 31 patients treated with posterior, pedicle-screw instrumented fusions at 1 institution (group PSF); and 31 patients with anterior, dual-rod instrumented fusions at another institution (group ASF). Multiple clinical and radiographic parameters were evaluated and compared. Results. The mean age, preoperative major curve magnitude, and preoperative lowest instrumented vertebral (LIV) tilt were similar in both groups (age: PSF = 15.5 years, ASF = 15.6 years; curve size: PSF = 50.3° ± 7.0°, ASF = 49.0° ± 6.6°; LIV tilt: PSF = 27.5° ± 6.5°, ASF = 27.8° ± 6.2°). After surgery, the major curve corrected to an average of 6.3° ± 3.2° (87.6% ± 5.8%) in the PSF group, compared with 12.1° ± 7.4° (75.7% ± 14.8%) in the ASF group (P < 0.01). At final follow-up, the major curve measured 8.0° ± 3.0° (84.2% ± 5.8% correction) in the PSF group, compared with 15.9° ± 9.0° (66.6% ± 17.9%) in the ASF group (P = 0.01). This represented a loss of correction of 1.7° ± 1.9° (3.4% ± 3.7%) in the PSF group, and 3.8° ± 4.2° (9.4% ± 10.7%) in the ASF group (P = 0.028). The LIV tilt decreased to 4.1° ± 3.4° after surgery in the PSF group, and 4.5° ± 3.7° in the ASF group. At final follow-up, the LIV tilt was 5.1° ± 3.5° in the PSF group, and 4.5° ± 3.7° in the ASF group. EBL was identical in both groups, and length of hospital stay was significantly (P < 0.01) shorter in the PSF group (4.8 vs. 6.1 days). There were no complications in either group which extended hospital stay or required an unplanned second surgery. Conclusion. At a minimum of 2-year follow-up, adolescents with Lenke 5C curves demonstrated statistically significantly better curve correction, less loss of correction over time, and shorter hospital stays when treated with a posterior release with pedicle screw instrumented fusion compared with an anterior instrumented fusion with dual rods for similar patient populations.