OBJECTIVE:Adult spinal deformity (ASD) surgery patients maintain upright posture by using numerous compensatory mechanisms. The distribution of this compensation throughout the skeleton has not been fully investigated. METHODS:Patients with lumbar deformity curves undergoing fusion from T10 to the pelvis were included. Groups were stratified by Scoliosis Research Society (SRS)-Schwab sagittal deformity severity (mild, moderate, and severe). Compensation was determined based on the published values of asymptomatic individuals by Bao et al. (2018), with patients outside 1 standard deviation of the mean values deemed to be compensating. Adequate deformity correction was determined based on matching published sagittal age-adjusted score (SAAS) criteria. Means comparisons tests assessed differences between cohorts at each time point. RESULTS:In total, 379 ASD patients were included (mean age 66.7 ± 10.2 years, body mass index 28.4 ± 5.4 kg/m2, Charlson Comorbidity Index 1.20 ± 1.73). In total, 23.8% of patients had mild deformity, 19.2% moderate, and 57% severe. The severe deformity cohort generally demonstrated the highest rates of compensation across all regions at different time points. At baseline, the severe and moderate cohorts demonstrated predominantly lower limb-dominant compensation, with the highest frequencies of compensation seen at the knee and pelvis. In the mild cohort, knee compensation was relieved by 1 year when adequate correction was achieved. For the moderate cohort, hip and pelvic compensation were relieved first, with knee compensatory relief occurring by 2 years. For the severe cohort, pelvic compensation was relieved first, with global lower limb and thoracic compensation subsequently occurring. CONCLUSIONS:There is notable variation in how ASD patients compensate as the severity of their deformity progresses. There is also variation in how these patterns are altered postoperatively.
Background:Anterior lumbar interbody fusion (ALIF) is a common surgical procedure for treating degenerative discs in the lumbar spine. The popularity of ALIF continues to rise due to favorable reported outcomes, leading to the introduction of the oblique lumbar interbody fusion (OLIF) approach, which yields similar outcomes with less morbidity. Designs of cages are also evolving to improve fusion rate and optimize clinical outcomes. This study aims to evaluate the performance and safety of SPIRA cages (Camber Spine Technologies, King of Prussia, PA, USA), which are designed and constructed using a novel patented three-dimensional (3D)-printed titanium open-arch architecture design. Methods:This was a single center, ambispective study of consecutive patients previously treated with lumbar open-arch cages at L4-5 and/or L5-S1, with or without supplemental fixation. Prospective lumbar computed tomography (CT) scan at minimum 12 months postoperatively was used to define the primary study objectives, interbody fusion, and implant subsidence. The secondary objectives were to evaluate safety from the retrospective medical data, including adverse events (AEs) related to the device or procedure and any consequential follow-up operations/revisions. Study inclusion criteria selected patients with intractable back and/or leg pain having clinical and radiological evidence of lumbar degenerative disc at L4-5 and/or L5-S1 who failed 6 months of conservative treatment and had OLIF or ALIF surgeries from an oblique approach. The patients were at least 18 years of age and were able to provide informed consent to participate per study protocol. Results:A total of 33 subjects with 39 L4-5 and/or L5-S1 levels were included in the study. The cohort had a mean age of 57 years, a mean body mass index (BMI) of 32 kg/m2, and they were 60.6% female. All of the subjects had at least one comorbidity, and 78.8% (26/33) of subjects presented with two or more. Considering levels treated, L4-5 and L5-S1 were 43.6% (17/39) and 56.4% (22/39), respectively. The mean follow-up was 30 months. The interbody fusion rate was 97.44% and the occurrence of implant subsidence was 12.82% in the treated levels. There were no device-related complications reported, and a third of subjects experienced probable or direct procedure-related complications. The revision rate at the index level was 9.0%. Conclusions:Surgeons have many options when selecting an interbody cage for treating a degenerative disc. While surgical technique is fundamental to interbody fusion efficacy and safety, the cage design has been shown to influence these factors since the cage design itself can promote bone growth and reduce the risk of subsidence. The current study reporting fusion and subsidence rates for the open-arch designed cages supports this novel design's efficacy and safety. The results of this study support the efficacy of the open-arch cage design, which has focused on promoting interbody fusion and minimizing subsidence while maintaining implant safety.
STUDY DESIGN:Retrospective analysis of prospectively collected database. OBJECTIVE:Adult spinal deformity (ASD) has increasingly been treated with minimally invasive surgical (MIS) techniques. The authors sought to identify factors associated with delayed deterioration of ODI between 1 and 2 years postoperatively following minimally invasive surgery (MIS) for adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA:Coronal malalignment is known to be associated with patient disability but the extent to which coronal alignment is associated with delayed deterioration after circumferential MIS surgery for ASD is unknown. METHODS:A retrospective analysis of prospectively collected data from the Minimally Invasive Surgery International Spine Study Group (MIS-ISSG) was conducted, including 67 patients who underwent circumferential MIS for ASD with one and two-year follow-ups. The patient cohort was dichotomized by identifying patients who reported higher ODI scores at 2 years than 1 year (somewhat improved) and compared with patients who reported stable or improved ODI over the same time course (very improved). Preoperative and postoperative factors influencing ODI changes were analyzed, focusing on radiographic outcomes and complications. RESULTS:Of the 67 patients, 31 reported an increase in ODI at two years compared with one year but these patients continued to show an improvement in ODI compared to preoperative baseline. Statistical analyses revealed no significant differences in baseline demographic, surgical, or preoperative characteristics between the "somewhat improved" (2-year ODI>1-year ODI) and "very improved" (2 y ODI≤1 y ODI) cohorts (P>0.05). However, the somewhat improved group had a significantly higher mean central sacral vertical line (CSVL) at all follow-up intervals (6-week CSVL mean 36.26 mm in the Somewhat improved group versus 22.8 mm in the very improved group, P=0.01). CONCLUSION:Early post-operative coronal malalignment is associated with delayed changes in functional outcomes following MIS for ASD.
BACKGROUND CONTEXT Cervical disc replacement has emerged as an alternative to fusion for 1- and 2-level disease. Periprosthetic bone loss is a recognized radiographic finding, though its clinical significance remains unclear. PURPOSE To evaluate the association between periprosthetic bone changes and clinical outcomes, including patient-reported outcomes and index level revision. STUDY DESIGN/SETTING Subanalysis of FDA IDE trials with mid- and long-term follow-up. PATIENT SAMPLE Patients treated with PEEK-on-ceramic cervical disc replacement at 1 level (n=146) or 2 levels (n=178). OUTCOME MEASURES NDI, neck pain, arm pain, SF-12, and index level revision. METHODS Radiographs were evaluated for anterior bone loss and cystic changes. Patient-reported outcomes were compared with preoperative values through 5 years. Associations were analyzed using general linear mixed models. RESULTS No significant association was found between bone changes and clinical outcomes, including NDI, pain scores, or SF-12 measures. Index level revision rates were similar regardless of bone changes. CONCLUSIONS Periprosthetic bone changes were not associated with clinical outcomes for 5 years. These findings suggest limited aggregate clinical impact, though long-term follow-up is ongoing. FDA Device/Drug Status Simplify Cervical Disc (Approved for this indication)
BACKGROUND AND OBJECTIVES:Circumferential minimally invasive surgery (cMIS) techniques in adult spinal deformity (ASD) surgery may reduce physiological burden compared with open technique, but their utility in octogenarians has not been previously assessed. METHODS:Operative ASD patients aged 80 years or older with complete baseline (BL) and 2-year postoperative radiographic and health-related quality of life data were assessed and compared by surgical technique: open vs cMIS. Propensity score matching aligned groups by BL Charlson Comorbidity Index (CCI), C7-S1 sagittal vertical axis, pelvic incidence minus lumbar lordosis mismatch, and C7 plumb line. BL and peri/postoperative factors were assessed using analysis of variance and Bonferroni-adjusted analysis of covariance while controlling for BL CCI and posterior fusion length. RESULTS:Thirty-four octogenarian ASD patients met inclusion criteria, of whom 29.4% underwent cMIS and 70.6% underwent open correction. cMIS patients were less likely to require surgical intensive care unit (10% vs 75%, P < .001) and had shorter hospital stays (4.6 vs 10.1 days, P = .013). Open patients reported higher Scoliosis Research Society-22 Appearance and Mental domain scores (both P < .005) and more frequently reached minimal clinically important difference in both domains by 2 years (P = .025, .024). cMIS patients more often required reoperation for radiographic sagittal imbalance by 2 years when controlling for CCI and levels fused (20.0% vs 8.3%, P < .001). No deaths occurred in either group by 2 years. CONCLUSION:In octogenarians undergoing ASD surgery, cMIS reduced physiological burden but had higher reoperation rates, whereas open surgery showed greater durability.
