Nassr, Ahmad N

BACKGROUND AND OBJECTIVES: Transforaminal lumbar interbody fusion (TLIF) allows for direct and indirect decompression and segmental lordosis in sagittal plane correction. This study compares the effectiveness of “Bullet” type and “Banana” type devices for sagittal plane correction. METHODS: Patients who underwent 1-level or 2-level TLIF for degenerative pathology at a single tertiary care center were identified. Details were extracted on demographics, interbody dimensions, and preoperative and postoperative lumbopelvic parameters from upright radiographs. Cages were categorized as “Bullet” or “Banana” type based on morphology and manufacturer description of optimal position. Univariable comparisons between levels treated with “Bullet” and “Banana” type interbodies were performed. Multivariable linear regression was performed to identify independent predictors of postoperative segmental lordosis and change in segmental lordosis. RESULTS: One hundred and ninety eight unique patients (median 66.6 years; [IQR 59.5, 73.7]; 56.6% female) were included with 241 levels treated, of which 114 (52.7%) were treated with “Banana” type interbodies and 127 (47.3%) with “Bullet” type. “Banana” type interbodies afforded both greater postoperative segmental lordosis (8.1 [6.2, 10.7] vs 7.5 [5.2, 9.6]; P = .048) and greater increase in segmental lordosis (3.3 [0.7, 7.0] vs 2.3 [0.1, 4.2]; P = .015). On multivariable linear regression, only preoperative segmental lordosis (β = 0.322 per degree; [0.244, 0.399]; P < .001), implant listed lordosis (β = 0.146 per degree; 95% CI [0.048, 0.244]; P = .004), preoperative pelvic incidence (0.072 per degree; [0.034, 0.111]; P < .001), and use of bilateral TLIF windows (β = 3.133; [1.213, 5.053]; P = .001) were predictive of postoperative segmental lordosis. CONCLUSION: The present analysis suggests that baseline lumbopelvic anatomy, interbody lordosis, and the use of bilateral TLIF windows are the most important predictors of postoperative segmental lordosis. Use of “Banana” vs “Bullet” type interbodies was not predictive of segmental lordosis achieved on immediate postoperative upright radiographs. Further work is merited to determine whether the 2 interbody types demonstrate differences regarding subsidence risk or maintenance of correction.

Background: The purpose of this study was to report on 2-year results of vertebral body tethering (VBT), performed under a Food and Drug Administration protocol, to obtain insight into outcomes and complications. Methods: Forty prospectively enrolled patients with adolescent idiopathic scoliosis (AIS) who had a Sanders score of ≤4 or a Risser score of ≤2 underwent VBT for curves between 40° and 70°. Surgical, radiographic, and patient-reported outcomes were reviewed at a minimum 2-year follow-up. Results: Mean age at surgery was 13 (range, 10 to 16) years. The 40 patients were 90% female; 95% White, 2.5% other, and 2.5% unreported; and 92.5% non-Hispanic, 5% Hispanic, and 2.5% unreported. A mean of 8 (range, 5 to 12) levels were instrumented. Most patients were at Sanders 4 (65%) and Risser 0 (63%). Mean length of stay was 3 ± 1 days, estimated blood loss was 236 ± 158 (range, 25 to 740) mL, and operative time was 4.4 ± 1.4 hours. Mean correction of the major curve was 44% (range, 22% to 95%) on the 3-month standing radiograph, 49% at 1 year, and 46% (range, −10% to 93%) at 2 years. The mean major Cobb angle improved from 51° ± 8° (range, 40° to 70°) preoperatively to 27° ± 11° (range, 3° to 56°) at 2 years. Success at 2 years, defined by a Cobb angle of <35° and no reoperation, was seen in 30 patients (75%) and was associated with a mean Cobb angle of <35° on the first postoperative standing radiograph (p < 0.001). Twelve patients (30%) demonstrated improvement in the curve with growth. By 2 years, 2 (5%) of the patients underwent repeat surgery (1 release for overcorrection, 1 lumbar VBT for lumbar curve progression after thoracic VBT). The Scoliosis Research Society (SRS) satisfaction score improved 2 years following surgery (p < 0.001), but other SRS domains only remained stable over time. Beyond 2 years, 1 additional lumbar tether was required after thoracic VBT, 1 implant was removed, and 3 fusions were performed, for a 10% fusion rate and overall 20% reoperation rate at a mean of 3.8 ± 1.1 years of follow-up. The rate of cord breakage in the study population was 20%. Conclusions: In skeletally immature patients treated in the U.S. under a prospective Investigational Device Exemption, there was a 75% rate of successful outcomes at 2 years. Most correction was obtained at the time of surgery, and inadequate intraoperative curve correction was associated with a higher Cobb angle on the first postoperative standing radiograph and failure by 2 years. Level of Evidence: Therapeutic Level II . See Instructions for Authors for a complete description of levels of evidence.

Background: The comparative effectiveness of decompression plus lumbar facet arthroplasty versus decompression plus instrumented lumbar spinal fusion in patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis is unknown. Methods: In this randomized, controlled, Food and Drug Administration Investigational Device Exemption trial, we assigned patients who had single-level lumbar spinal stenosis and grade-I degenerative spondylolisthesis to undergo decompression plus lumbar facet arthroplasty (arthroplasty group) or decompression plus fusion (fusion group). The primary outcome was a predetermined composite clinical success score. Secondary outcomes included the Oswestry Disability Index (ODI), visual analog scale (VAS) back and leg pain, Zurich Claudication Questionnaire (ZCQ), Short Form (SF)-12, radiographic parameters, surgical variables, and complications. Results: A total of 321 adult patients were randomized in a 2:1 fashion, with 219 patients assigned to undergo facet arthroplasty and 102 patients assigned to undergo fusion. Of these, 113 patients (51.6%) in the arthroplasty group and 47 (46.1%) in the fusion group who had either reached 24 months of postoperative follow-up or were deemed early clinical failures were included in the primary outcome analysis. The arthroplasty group had a higher proportion of patients who achieved composite clinical success than did the fusion group (73.5% versus 25.5%; p < 0.001), equating to a between-group difference of 47.9% (95% confidence interval, 33.0% to 62.8%). The arthroplasty group outperformed the fusion group in most patient-reported outcome measures (including the ODI, VAS back pain, and all ZCQ component scores) at 24 months postoperatively. There were no significant differences between groups in surgical variables or complications, except that the fusion group had a higher rate of developing symptomatic adjacent segment degeneration. Conclusions: Among patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis, lumbar facet arthroplasty was associated with a higher rate of composite clinical success than fusion was at 24 months postoperatively. Level of Evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Background: Pedicle subtraction osteotomy (PSO) is a powerful tool for sagittal plane correction in patients with rigid adult spinal deformity (ASD); however, it is associated with high intraoperative blood loss and the increased risk of durotomy. The objective of the present study was to identify intraoperative techniques and baseline patient factors capable of predicting intraoperative durotomy. Methods: A tri-institutional database was retrospectively queried for all patients who underwent PSO for ASD. Data on baseline comorbidities, surgical history, surgeon characteristics and intraoperative maneuvers were gathered. PSO aggressiveness was defined as conventional (Schwab 3 PSO) or an extended PSO (Schwab type 4). The primary outcome of the study was the occurrence of durotomy intraoperatively. Univariable analyses were performed with Mann–Whitney U tests, Chi-squared analyses, and Fisher’s exact tests. Statistical significance was defined by p < 0.05. Results: One hundred and sixteen patients were identified (mean age 61.9 ± 12.6 yr; 44.8% male), of whom 51 (44.0%) experienced intraoperative durotomy. There were no significant differences in baseline comorbidities between those who did and did not experience durotomy, with the exception that baseline weight and body mass index were higher in patients who did not suffer durotomy. Prior surgery (OR 2.73; 95% CI [1.13, 6.58]; p = 0.03) and, more specifically, prior decompression at the PSO level (OR 4.23; 95% CI [1.92, 9.34]; p < 0.001) was predictive of durotomy. A comparison of surgeon training showed no statistically significant difference in durotomy rate between fellowship and non-fellowship trained surgeons, or between orthopedic surgeons and neurosurgeons. The PSO level, PSO aggressiveness, the presence of stenosis at the PSO level, nor the surgical instrument used predicted the odds of durotomy occurrence. Those experiencing durotomy had similar hospitalization durations, rates of reoperation and rates of nonroutine discharge. Conclusions: In this large multisite series, a history of prior decompression at the PSO level was associated with a four-fold increase in intraoperative durotomy risk. Notably the use of extended (versus) standard PSO, surgical technique, nor baseline patient characteristics predicted durotomy. Durotomies occurred in 44% of patients and may prolong operative times. Additional prospective investigations are merited.

Case: A 71-year-old woman sustained C1 lateral mass and type 2 odontoid fractures 3 years after C2-T2 anterior-posterior fusion. She was treated with C1-C4 instrumentation without fusion for 9 months followed by instrumentation removal to restore atlantoaxial motion. After instrumentation removal, she maintained clinically relevant cervical lateral bending, rotation, and flexion and extension. Conclusion: The loss of upper cervical motion after C1-C2 instrumented fusion may be debilitating for patients in the setting of previous subaxial cervical fusion. Temporary instrumentation without fusion may allow for preservation of upper cervical motion in patients with concomitant C1 and C2 fractures above a previous cervical fusion.

Case: A 41-year-old man sustained occipitocervical dislocation (OCD) and atlantoaxial dislocation (AAD) injuries in a motor vehicle collision. These injuries were treated nonoperatively with a hard cervical collar and activity restrictions with an excellent result at 4-year follow-up. Conclusion: OCD and AAD injuries require prompt diagnosis and immobilization. Standard of care for coexisting injuries is occipitocervical fusion; however, some patients have coexisting injuries which may prevent operative treatment. These polytrauma patients require a creative nonoperative approach with close follow-up to avoid neurologic decline.