BACKGROUND CONTEXT Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) remain common mechanical complications after long-segment adult spinal deformity (ASD) surgery. Although global sagittal alignment targets guide deformity correction, they may overlook localized biomechanical variations at the thoracolumbar junction (TLJ), particularly in lower thoracic constructs extending to the pelvis. PURPOSE To identify TLJ-specific alignment thresholds associated with PJF after lower thoracic to pelvis fusion in ASD using decision-tree analysis. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE Adult ASD patients (≥18 years) undergoing long-segment fusion from upper instrumented vertebrae T9–T12 to the pelvis. OUTCOME MEASURES PJK and PJF. PJF was defined as proximal junctional angle (PJA) ≥28° with ΔPJA ≥22°, UIV/UIV+1 fracture, implant failure, or revision with proximal extension. PJK was defined as PJA ≥10° with ΔPJA ≥10°. METHODS Standing full-length radiographs were analyzed pre- and postoperatively. TLJ parameters included T10–L2 Cobb angle (CA), thoracolumbar slope (TLS), upper instrumented vertebra slope (UIVS), and UIV pelvic angle (UIVPA), along with perioperative changes. Additional metrics included changes in T4–L1PA, T4–UIVPA, and UIV–L1PA mismatch. Classification and Regression Tree (CART) and Chi-square Automated Interaction Detection (CHAID) algorithms were used to identify alignment thresholds associated with PJF. Significant variables were entered into multivariable logistic regression with demographic covariates. RESULTS A total of 135 patients were included (mean age 66.3±8.4 years; 27% male; BMI 26.5±5.6 kg/m2; pelvic incidence 52.4±11.4°). Decision-tree analysis identified TLJ thresholds associated with increased PJF risk: postoperative UIVS >16.5°, L1PA correction >4.25°, T10–L2 CA change ≤−6.95°, and postoperative TLS >20.3°. The CART model demonstrated 83% accuracy (95% CI 75.5–88.9), sensitivity 42%, specificity 78%, and AUC 0.72. The CHAID model demonstrated 81% accuracy, sensitivity 90%, specificity 48%, and AUC 0.71. Multivariable regression identified increased PJF risk with older age (OR 1.09 per year, p=0.04), L1PA correction >4.25° (OR 9.6, p<0.01), postoperative TLS >20.3° (OR 4.3, p=0.03), and postoperative T10–L2 CA >5.4° (OR 8.2, p=0.04). CONCLUSIONS TLJ-specific alignment parameters are strongly associated with PJF following lower thoracic to pelvis fusion in ASD. Overcorrection beyond regional biomechanical thresholds, particularly in older patients, may increase failure risk. Incorporating TLJ-specific alignment targets into surgical planning may improve construct durability by avoiding region-specific overcorrection not captured by global alignment metrics. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs.

Abstract Background Accurate underlying cause of death (CoD) data is critical for informing public health policy, but inaccurate CoD assignment, here called garbage code (GC) deaths, compromise CoD research and monitoring. Since 1997, GCs have consistently made up over 20% of all underlying CoDs in Sweden, but the distribution of GC deaths by sociodemographic status of the deceased remains poorly understood. Methods We used the Swedish Cause of Death Register containing 2.50 million death records from 1997 to 2023. We mapped each record to the Global Burden of Disease (GBD) project cause list and categorized GC deaths by disease groups. We calculated the fraction of deaths that were GCs by individual age, sex, region of death, and highest educational attainment. We performed redistribution of GCs onto well-defined CoDs and assessed the odds of GC assignment with a binomial logistic regression. Results Since 1997, Sweden has coded at least 23% of deaths to GCs each year with 25.5% coded to GCs in 2023. The lowest educated consistently received more GC deaths, with 45.8% more GC deaths relative to non-GC deaths between ages 20 and 39 compared to the highest educated, and there were more GC deaths in (1) infections, (2) blood and endocrine diseases, (3) injuries, (4) cancers, and (5) maternal, neonatal, and congenital (MNC) diseases in 2023. GC deaths among the highest educated have continued to increase in infections, injuries, cardiovascular, digestive, and MNC diseases. After redistribution, well-defined death counts among the lowest educated increased by over 20% in 13 of the leading 20 CoDs in Sweden. Our model suggested low education increased the likelihood of having a GC by 12.8% (11.4%-14.2%) compared to the highest educated. This was second to point estimates of standardized age at death (25.2% [24.8%-25.6%]) and exceeded sex (12.1% [11.4%-12.8%] increase for males) and region (at most 7.3% [6.6%-8.1%] decrease for death outside of Stockholm). Conclusions We found consistent trends of high GC level in Sweden with doctors assigning more GCs to the lowest educated. Our results reveal stark sociodemographic disparities in CoD coding in Sweden and it is probable that similar disparities would be found elsewhere. This underscores the need for improving procedures and national guidelines in CoD assignment to correctly represent all social groups in research.

BACKGROUND CONTEXT Over the past decade, increased emphasis on preoperative optimization, multidisciplinary protocols, and enhanced postoperative care has aimed to reduce morbidity after adult spinal deformity (ASD) reconstruction. Whether these efforts have resulted in sustained reductions in postoperative medical complications remains uncertain. PURPOSE To evaluate temporal trends in postoperative medical complications following ASD surgery. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE Adults aged ≥18 years undergoing ≥5-level fusion to the pelvis for spinal deformity between 2017 and 2023, excluding cases of trauma, tumor, or infection. OUTCOME MEASURES Postoperative medical complications classified using the ISSG-AO system. METHODS Surgical invasiveness was quantified using the ASD–Surgical and Radiographical (ASD-SR) score and analyzed as both a continuous variable and stratified into low- and high-risk groups based on the cohort median. Annual complication rates were assessed using linear regression and the Cochran–Armitage trend test. Multivariable logistic regression identified factors associated with complications, adjusting for age, comorbidities, and surgical invasiveness. RESULTS A total of 311 patients were included (median age 68 years; low ASD-SR: n=157, high ASD-SR: n=154). Baseline demographics, BMI, and Charlson Comorbidity Index were similar between groups. The high ASD-SR group had greater fusion levels (10.9 vs 8.1, p<0.001), more osteotomies (95% vs 48.4%, p<0.001), and higher blood loss (1296.7 vs 964.3 mL, p=0.003), with similar rates of primary surgery (p=0.9). The overall medical complication rate decreased by 2.5% annually (p=0.01), driven by a 1.4% annual reduction in cardiopulmonary events (p=0.01), while gastrointestinal and renal complications remained stable (p>0.05). Complication rates were similar between low and high ASD-SR groups (16.7% vs 17.3%, p=1), regardless of complication type or timing. Baseline comorbidity burden and surgical invasiveness remained stable over time (p=0.4). Overall, medical complications occurred in 17% of patients, most commonly gastrointestinal (7.7%) and cardiopulmonary (5.1%), followed by renal (1.3%), with other complications being rare. Multivariable analysis identified year of surgery (OR 0.80, p=0.002) and age (OR 0.97 per year, p=0.03) as associated with lower odds of complications, with no interaction between year and ASD-SR group. CONCLUSIONS Medical complications after ASD reconstruction have steadily declined over seven years despite stable patient risk profiles and surgical complexity. These findings suggest that advancements in perioperative care and system-level safety initiatives have improved surgical outcomes, supporting continued investment in multidisciplinary perioperative management strategies. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs.

Older men may be at particular risk for skeletal complications following orthopaedic procedures but seldom have bone health evaluated. This prospective study investigated bone quality and risk of complications in men undergoing spine fusion. Older age, revisions, procedures involving > 5 vertebrae, and abnormal microarchitecture increased the risk of postoperative skeletal complications. Perioperative bone health is seldom evaluated in male patients. Older men, in particular, may be at elevated risk for skeletal complications following orthopaedic procedures such as spine fusion; however, few studies have evaluated preoperative skeletal health or risk factors for postoperative complications in this population. This prospective cohort study investigated relationships between preoperative bone health and postoperative outcomes in older men having spine fusion. We hypothesized that men with preoperative skeletal deficits would have higher rates of postoperative complications. Preoperative skeletal evaluation included DXA, lumbar spine QCT, and high-resolution peripheral CT (HR-pQCT). Postoperative complications were assessed by radiographs and CTs. Among 63 men enrolled (mean age 66 ± 8 years), only one had osteoporosis based upon the lowest DXA T-score (spine, hip, or wrist) and 15

STUDY DESIGN:Biomechanical cadaveric study. OBJECTIVE:Assess the accuracy and precision of robotically placed cervical pedicle screws (CPS). SUMMARY OF BACKGROUND DATA:Posterior cervical fusion (PCF) can be performed using lateral mass screws or pedicle screws. Although pedicle screw trajectories are longer and allow for the placement of larger screws, these screws must be placed accurately as they traverse a narrow corridor bordered by critical neurovascular structures. Robotic technology may have the potential to improve the safety and accuracy of CPS, which could facilitate the routine use of these biomechanically favorable screws in PCF. METHODS:A cadaveric study was performed to assess the accuracy of subaxial CPS placement using robotic-assisted navigation in 3 cadavers. Computed tomography (CT) scans were performed preoperatively, and trajectories were planned in Mimics software. Intraoperative fluoroscopic registration was performed, and bilateral pedicle screws were drilled and placed through the robotic end-effector from C3-C7. Postoperative CT scans were performed. Accuracy was defined as the mean absolute error (MAE), precision was defined as 2 SD, and systematic error was defined as the signed mean error (SME) when comparing the planned versus placed pedicle screw positions. An automated computer vision algorithm that measures postoperative deviation from the preoperative plan was used to assess the final tip, tail, and mid-pedicle screw position in 3 dimensions. RESULTS:A total of 30 screws were successfully placed without registration failures. When compared with the planned screw trajectory, the accuracy/deviation of the tail in the ML and SI dimensions was 1.76 mm and 1.53 mm, respectively. Accuracy of the mid-pedicle position in the ML and SI dimensions was 1.06 and 1.17. Accuracy of the tip in the ML and SI dimensions was 0.67 and 0.87 mm, respectively. Angular deviation was 3.50 degrees. CONCLUSIONS:Robotic-assisted posterior cervical pedicle screw placement is highly accurate.

This study compares the range of motion (ROM) in all three planes in patients with Scheuermann kyphosis (SK) to healthy controls using surface topographic (ST) scanning. SK patients and healthy controls between 11–21 years old were recruited prospectively. Patients underwent ST scanning in maximal forward bend, twist to the right and left, and side-bend to the right and left. Sagittal, axial, and coronal ROM were computed using an automated pathway. An analysis of variance was used to determine significant differences in the ROM (coronal, axial, and sagittal) and asymmetry (coronal and axial) of SK patients versus controls. Scoliosis Research Society (SRS) 22r total, self-image, pain and function, as well as Patient-Reported Outcome Measurement Information System (PROMIS) mobility, physical activity and pain interference scores, and HSS Pedi-FABS were collected for all patients. 23 patients with SK and 98 controls were analyzed. SK group was 78.3

STUDY DESIGN:Retrospective analysis. OBJECTIVE:To characterize recovery trajectory after anterior cervical discectomy and fusion (ACDF) by identifying recovery phases and their inflection timepoints. SUMMARY OF BACKGROUND CONTEXT:Understanding how the number of fused levels influences recovery is essential for tailoring surgical decisions and postoperative management. MATERIALS AND METHODS:This study included patients who underwent primary ACDF for degenerative cervical disease. Outcome measures included the Neck Disability Index (NDI), and numeric rating scale (NRS) for neck and arm pain, collected longitudinally. Segmented regression modeling was employed to predict recovery trajectories by phase-specific slopes, and inflection timepoints between phases. RESULTS:A total of 290 patients were included. Segmented regression identified three improvement phases of NDI: early improvement phase (EIP), late improvement phase (LIP), and plateau phase (PP), with two inflection timepoints between phases (EIP to LIP: day 43.4±6.7; LIP to PP: day 100.7±13.1). During EIP, the 1-level group demonstrated significantly steeper improvement slopes (-0.44 points/day in NDI) compared to ≥2-level (-0.35 points/day; P=0.001). The models for NRS for neck and arm pain detected two phases: the improvement phase and PP. Neck pain improved until day 24.1±2.6, while arm pain improved until day 10.6±2.0. Level specific model showed that the breakpoint for NRS neck occurred faster in 1-level compared to ≥2-level (18.0 ± 3.0 vs. 28.2 ± 4.0 d; P = 0.042). CONCLUSION:The recovery trajectory of disability following ACDF was characterized by three phases: rapid improvement until 4-6 weeks, slower improvement until 3-4 months, followed by symptom plateau after 4 months. A greater number of fused levels slows early disability recovery and delays neck‑pain relief. These findings are informative to tailor peri‑operative expectations and rehabilitation protocols to fusion length. LEVEL OF EVIDENCE:3.

Background:Aging is a major risk factor for IVD degeneration and chronic lower back pain. Comparing degenerative patterns in human and mice, a commonly used pre-clinical model, is crucial for validating it in preclinical mechanistic research. The goal of the study was to compare the effect of age and spine level on degeneration in human and mouse lumbar IVDs. Methods:T2-weighted MRI images of human lumbar spine were graded using the Pfirrmann system. H&E-stained mid-coronal sections of mouse lumbar IVDs were scored using the Melgoza and Chenna system. Age, gender, IVD level, and lumbar IVD degeneration scores, respectively, were used for statistical analysis in each species. Linear regression and one-way ANOVA with post hoc Tukey analysis were used to compare regression slopes and intercepts. Age conversion from mouse to human was performed according to the Jackson Laboratory's outline of mouse age and its human equivalents. Generalized estimating equations (GEE) were used to model continuous degeneration scores, accounting for intra-subject correlation due to multiple IVD levels per subject. Main effects included sex, IVD level (L1-S1), and age, with an interaction term assessing the impact of age across levels. An autoregressive correlation structure was specified. Results:Age significantly correlated with IVD degeneration in humans (p < 0.0001) and mice (p < 0.0002). And the IVD level predicted degeneration in both species (L5-S1 in human, and L6-S1 in mice). Normalizing age and pathology revealed an earlier onset of degeneration in humans than in mice. Conclusions:Age and spinal IVD level influence lumbar IVD degeneration in both human and mice with a higher rate of degeneration at the lumbosacral junction in both species. These findings suggest that mice are a suitable model for studying the cellular and molecular basis of IVD degeneration and associated neurological symptoms, with the L6-S1 level being the most relevant.

Study Design.Systematic review. Objective.To describe the various definitions of PJK and PJF used in spinal deformity literature and their utility over time. Summary of Background Data.Proximal junctional kyphosis or failure (PJK/PJF) is among the most common complications after long-segment fusions, but there is no consensus on their definitions. This presents challenges in understanding risk factors, management, and prevention strategies. Methods.A systematic literature review was performed on studies specifying a definition of PJK and/or PJF. PJK definitions were categorized as radiographic versus nonradiographic, and data were collected on PJK criteria, including the threshold for proximal junctional angle (PJA), change in PJA, vertebra selection for PJA measurement, and follow-up time points. PJF definitions were categorized as structural failure, need for revision, symptomatic failure, and radiographic (angular). Results.A total of 359 studies defining PJK and/or PJF were identified. While 56% of studies used the definition PJA>10 degrees and PJA change from baseline>10 degrees, the remainder expressed significant heterogeneity with respect to criteria for the magnitude of PJA and degree of PJA change. The most common vertebrae assessed were UIV/UIV+2 (74%), and the most common minimum follow-up (mFU) listed was two years (60%). Mean FUs for studies varied considerably even in studies with the same mFU, from 2.1 to 8.9 years (2-yr mFU) and 1.1 to 4.0 years (1-yr mFU). PJF definitions were most commonly structural (58%) or defined as a need for revision (48%), with a much less common use of PJA thresholds (23%). Conclusions.The challenges faced in preventing proximal junctional complications are mired in the heterogenous groundwork by which PJK and PJF are defined. Most definitions of PJK use radiographic thresholds without consideration of clinical relevance and variations in individual alignment. Conversely, definitions of PJF are based on clinical criteria, which are often subjective. Future research should focus on understanding the mechanisms of PJK/PJF, as only then will we be able to accurately define and prevent these complications.

To describe the temporal evolution of the main causes of mortality in Minas Gerais (MG), Brazil, and to verify the association with socioeconomic indicators. This is a mixed ecological study in which age-standardized mortality rates were calculated per 100,000 inhabitants due to noncommunicable diseases (NCDs), communicable, neonatal and nutritional diseases (NNDs) and external causes (ECs) for 853 municipalities in MG, according to data from the Global Burden of Disease (GBD) study, in the three-year periods 2000 to 2002 (T1), 2009 to 2011 (T2) and 2016 to 2018 (T3). Between T1 and T3, mortality due to NCDs predominated; there was a 22.4% decrease in the rates for NCDs (553.6 to 429.9) and a 29% decrease in the rates for NCDs (83 to 58.9), and a 3.5% increase in EC (62.2 to 64.4). The correlation coefficients were positive (R > 0.70; p < 0.05) and higher mortality rates were found in areas with worse socioeconomic status.

Study Design Retrospective cohort study. Objectives Severe neck pain has traditionally been considered a relative contraindication for cervical disc replacement (CDR) due to risk of persistent neck pain from the remaining mobile segment. However, recent studies suggest potential for neck pain improvement with CDR. This study aimed to compare postoperative improvements in neck pain and disability between patients undergoing anterior cervical discectomy and fusion (ACDF) and CDR. Methods Predominant neck pain was defined as neck pain equal to or greater than arm pain preoperatively (visual analog scale [VAS]) and neck disability index (NDI) > 20. Patients with predominant neck pain who underwent 1- or 2-level ACDF or CDR for radiculopathy between 2017 and 2023 were included. Patient-reported outcomes (NDI, VAS) were assessed up to 1 year postoperatively. Inverse probability of treatment weighting (IPTW) was used to control for confounders. Linear mixed-effect models were applied to compare postoperative outcomes. Results A total of 179 patients (105 ACDF, 74 CDR) were included. Both groups showed significant improvement in NDI and VAS neck scores from baseline to 1 year (NDI: β = −1.81, P < .001; VAS neck: β = −.26, P < .001). After IPTW, no significant differences were found between ACDF and CDR across all PROMs up to 1 year (NDI: β = −0.44, P = .09; VAS neck: β = −.07, P = .10). Conclusion CDR was associated with postoperative improvements in neck pain and disability comparable to those observed with ACDF in patients with predominant neck pain and radiculopathy. These findings suggest that CDR may be a reasonable treatment option for selected patients.

Study DesignRetrospective cohort study.ObjectiveTo quantify and compare the carbon footprint (CF) of open and MIS microdiscectomy.MethodsThe study included 161 patients undergoing primary 1 level open or minimally invasive surgery (MIS) for lumbar disc herniation between 2018 and 2022. Life cycle assessment (LCA) modeling was used to calculate the CF produced during the distribution, use and waste phases of each item used during surgery. Independent samples t-tests and Chi square or Fischer's exact tests were used to compare the CF of open and MIS procedures.ResultsThere were 161 cases (100 MIS, 61 Open). MIS had a significantly higher overall CF (114.67 ± 60.06 kg-CO2e) vs open surgery (95.15 ± 45.45 kg-CO2e, P = 0.021). Key contributors included disposable surgical supplies, energy-intensive OR equipment, and anesthetic gases. Only the waste phase had a significant difference in CF, with MIS producing more waste (MIS: 31.50 ± 25.67; Open: 18.18 ± 10.25; kg-CO2e; P < 0.001) and consuming more energy, especially for heating, ventilation, and air conditioning systems and fluoroscopy.ConclusionsMIS microdiscectomy results in higher CF and environmental costs compared to open procedures, highlighting the need for sustainable practices, especially waste reduction, use of reusable materials and optimized energy use in ORs. A multifaceted approach is crucial to mitigate the environmental impact of spine surgeries and should be applied to both MIS and open techniques.

Cadaveric study. Compare the accuracy and precision of robotic navigation (RAN), freehand (FH) and freehand navigation (NAV) techniques for pedicle screw placement. Three cadavers were assigned to the FH, NAV, and RAN methods. Cadavers were CT scanned preoperatively, then underwent bilateral T1-L5 screw planning. RAN and NAV screws were placed by one surgeon, while the FH screws were placed by a second surgeon. Automated computer vision techniques were used to assess the tip, tail, and mid-pedicle screw positions compared to the preoperative plan along three axes on postoperative CT scans. Systematic error, precision, and accuracy were defined by signed mean error, two standard deviations (SDs), and mean absolute error (MAE), respectively. A factorial ANOVA with pairwise comparisons was used with post-hoc t-tests using Bonferroni corrections. Eighty-seven screws were placed in three cadavers (24 RAN, 29 NAV, 34 FH). Fifteen screws were skipped due to registration difficulties (10 RAN, 5 NAV). RAN outperformed NAV and FH in regard to MAE angular deviation from planned screw trajectory (p < 0.001), the mid-pedicle in the superior-inferior direction (p = 0.002), and at the screw tip in all planes (p < 0.05), with a maximum error of 1.29 mm and 1.98° (vs. 2.29 mm and 5.23° for NAV and 5.67 mm and 11.18° for FH). No RAN screws had medial breach (1 (3.4

Background/Objectives: Sagittal spinal alignment goals for adult spinal deformity (ASD) surgery are predominantly derived from standing radiographs, despite the biomechanical relevance of sitting posture. Existing studies on sitting alignment involve young, healthy cohorts, which poorly represent ASD patients. This study assessed posture-dependent changes in spinopelvic parameters, including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and lumbar lordosis (LL), and examined how age, BMI, and gender influence these changes. Methods: In this retrospective cohort study, sitting and standing lateral radiographs of 1447 patients were evaluated. Spinopelvic parameters were measured, and changes (ΔPI, ΔPT, ΔSS, and ΔLL) were calculated. Multiple regression analysis was used to determine associations between these changes and age, BMI, and gender. Results: All parameters differed significantly between positions (p < 0.001); PT and PI increased in sitting (ΔPT = −19.20°; ΔPI = −4.52°), while SS and LL increased in standing (ΔSS = 14.67°; ΔLL = 18.44°). Older age correlated with increased ΔPT (p < 0.001) and ΔPI (p = 0.049) but reduced ΔLL and ΔSS (p < 0.001). Higher BMI was associated with decreased ΔPI, ΔPT, and ΔLL (p < 0.001, 0.003, and 0.025). Females showed greater ΔPT (p = 0.013) but smaller ΔPI, ΔSS, and ΔLL (p = 0.043, <0.001, and 0.001). Conclusions: Spinopelvic parameters vary significantly between sitting and standing positions, affected by age, BMI, and gender. The observed PI change suggests SIJ involvement, highlighting the need for posture-specific and demographic-adjusted alignment goals in ASD surgery to optimize outcomes.

BACKGROUND CONTEXT:Given the rising global prevalence of obesity, it is imperative to understand its effects on spine surgery outcomes. The influence of BMI on outcomes after adult spinal deformity (ASD) reconstruction has varied based on the center. The findings of this study may assist in the risk stratification process and informed patient surgeon counseling for ASD surgery. PURPOSE:The aim of this study was to perform a systematic review and meta-analysis to describe the impact of body mass index (BMI) on clinical and radiographic outcomes after ASD correction surgery. STUDY DESIGN/SETTING:A systematic review and meta-analysis. METHODS:This study followed the preferred reporting items for systematic reviews and meta-analyses guidelines (PRISMA). Studies reporting complication rates, sagittal alignment parameters, and PROMs for patients stratified by BMI that underwent spinal fusion procedures for the treatment of ASD were included. Pooled meta-analyses reporting odds ratios were performed for any complication, mechanical complication, medical complication, and infection variables. Pooled meta-analyses reporting standard mean differences were performed for pelvic incidence-lumbar lordosis (PI-LL) mismatch and sagittal vertebral axis (SVA) parameters in both preoperative and late postoperative settings. A qualitative analysis of PROMs data was conducted. RESULTS:The literature search identified 11 studies that compared outcomes of interest between low and high BMI cohorts, with a total of 3,150 patients. High BMI patient cohorts demonstrated significantly greater odds of developing any complication and mechanical complications. Despite a lack of difference in preoperative radiographic alignment, high BMI patient cohorts demonstrated significantly greater sagittal vertebral axis (SVA) and PI-LL mismatch at the final postoperative timepoint. Odds of pseudoarthrosis, revision, infection, and medical complications were not increased by high BMI. Estimated blood loss and operative time demonstrated no significant mean differences between the high and low BMI cohorts. High BMI cohorts reported higher postoperative ODI and VAS-legs scores compared to low BMI. No significant differences were reported in other PROMs measures. CONCLUSIONS:These findings suggest that high BMI patients have an increased risk of developing mechanical complications and worse postoperative sagittal alignment in comparison to low BMI cohorts following ASD correction.

Study DesignRetrospective cohort study.ObjectiveIn patients with multilevel degenerative lumbar pathology, the decision to extend fusion across all decompressed levels remains a subject of debate. While fusion provides stability in cases of instability or deformity, its necessity for adjacent levels without specific fusion indications is unclear. This study evaluates whether decompression alone at levels without clear fusion indications can achieve similar outcomes compared to spanning the entire decompression with fusion.MethodsThe present study is a retrospective cohort study. Patients who underwent one-level decompression and fusion with 2 level decompression (SLF) were propensity score matched with patients who underwent two-level decompression and fusion (DLF) for degenerative conditions of the lumbar spine. Patient-reported outcome measures (PROMs), complication rates, revision surgeries, and recovery kinetics were compared between the cohorts.ResultsAfter propensity score matching a total of 43 SLF patients were compared with 43 DLF patients. Early follow-up (<6 months) showed significantly higher SF-12 PCS scores in the SLF group (P = .042) and greater achievement of VAS-leg MCID (88.9% vs 59.4%, P = .012). Long-term outcomes (≥6 months) demonstrated no significant differences in ODI, VAS-back, VAS-leg, or SF-12 PCS scores between groups. There were no differences in intraoperative or perioperative complications. The postoperative complication rate was significantly higher in the DLF group (25.6% vs 7%, P = .019) including 4 DLF patients that underwent revision surgery while no SLF patients required revision during their follow up time.ConclusionSLF resulted in similar long-term outcomes compared to DLF with fewer revisions and adjacent segment symptoms. These findings suggest that "saving" a fusion level in cases without a specific fusion indication at the adjacent level may be warranted to optimize longevity of the construct. Further research is necessary to refine patient selection for fusion levels in degenerative lumbar disease.

INTRODUCTION:After posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS), there is alteration in trunk range of motion (ROM) in the coronal, sagittal and axial planes. Previous studies have shown that ROM decreases with increased number of levels fused, which may affect the ROM between patients who undergo non-selective thoracic fusion (NSF) and selective thoracic fusion (STF) patient groups. This study sought to longitudinally evaluate the ROM of the trunk in patients with AIS who underwent posterior spinal fusion, using surface topography, comparing STF and NSF patient motion at multiple time points postoperatively. METHODS:A retrospective review of data from a single-center prospective registry was conducted. Inclusion criteria required subjects to span 11-21 years of age at surgery, a diagnosis of AIS, and valid ROM measurements obtained via ST scanning. Axial, sagittal and coronal ROM was performed at six timepoints: preoperative, 6 weeks, 3, 6, 12, and 24 months postoperative. All patients had an upper instrumented vertebra (UIV) of T2, T3 or T4, and a lower instrumented vertebra (LIV) of T12, L1, L2 or L3. STF was defined as an LIV of T12 or L1, and NSF as LIV as L2 or L3. SRS22r was collected at all time points. Generalized estimation equation modeling across timepoints were conducted. RESULTS:54 patients were evaluated: 40 patients in the NSF group (average preoperative Cobb angle of 56.4 ± 12.3°) and 14 in the STF group (average preoperative Cobb angle of 57.4° ± 6.7°). In the NSF group, ROM in the coronal and axial planes decreased significantly postoperatively and remained significantly decreased at 24 months postoperatively (25% decrease in the axial plane, 20% in the coronal plane). Sagittal ROM had significant decrease in ROM at all time points, but at 2 years postoperatively was no longer significant, although still 17% decreased. In the STF group, all three planes had significantly decreased initially but axial and coronal planes returned to baseline (no significant difference from preoperative values) at 24 months, while sagittal plane motion remained significantly diminished, although only by 4%. STF demonstrated no difference in SRS22r total, pain or self-image scores between preoperative and 2 years, while NSF had worse SRS22r total, pain, and self image scores at 2 years vs. preoperative values. When comparing NSF to STF, there was diminished axial, sagittal and coronal plane range of motion at 24 months postoperatively, but no differences in SRS22r total. CONCLUSION:The coronal, sagittal, and axial ROM as measured by ST demonstrated significant decreases from preoperative to postoperative following PSF; however, this deficit trends towards improvement over time. Our data demonstrates that at two years, NSF has poorer motion than STF patients in all three planes.

STUDY DESIGN:Retrospective cohort study. OBJECTIVE:To compare distal lordosis (DL) and lumbar lordosis (LL) generated by single-level minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and open TLIF at L4-L5 and L5-S1. SUMMARY OF BACKGROUND DATA:Restoring or maintaining L4-S1 DL and LL is an important component of TLIF surgery. However, the current literature is conflicting regarding the effect of surgical approach on these postoperative sagittal parameters. METHODS:Preoperative DL and LL were compared to postoperative values among adult patients undergoing single-level MI- and open TLIF surgeries. Subgroup analyses were performed with patients stratified based on pre-operative DL (low<25°, normal ≥ 25°), pelvic incidence (PI) (low<45°, moderate 45-60°, high > 60°), and PI-LL (high ≥ 10°, normal <10°). Regression analyses were conducted determining factors associated with postoperative DL and LL. RESULTS:Of the 285 patients included in the study, 211 underwent MI-TLIF (74.0%) and 74 (26.0%) underwent open TLIF. Patients with a high preoperative PI obtained a significant increase in LL at 6-month follow-up with an open TLIF (Δ4.2°, P=0.009) but not with an MI-TLIF (Δ-0.8°, P=0.151). Patients with a preoperative DL ≥ 25° experienced a decrease in DL at 6-month follow-up with both an open TLIF (Δ-2.0°, P=0.013) and MI-TLIF (Δ-1.4°, P=0.011). Patients with a preoperative DL ≥ 25° also experienced a decrease in LL at 6-month follow-up with an MI-TLIF (Δ-1.0°, P=0.002) but not with an open TLIF (Δ-0.3°, P=0.552). Patients with a preoperative DL<25° obtained an increase in both DL and LL with both MI-TLIF and open TLIF. CONCLUSION:Both MI-TLIF and open TLIF are effective for improving DL and LL among patients with a low preoperative DL (<25°). However, patients with a high preoperative PI (>60°) may benefit from an open approach for a greater restoration and maintenance of LL. LEVEL OF EVIDENCE:3.

Background/Objectives: While the economic cost of adult spinal deformity (ASD) surgery has been studied extensively, its environmental impact is unknown. The aim of this study is to determine the carbon footprint (CF) associated with ASD surgery. Methods: ASD patients who underwent > four levels of corrective surgery between 2017 and 2021 were included. The open group included a posterior-only, single-stage technique, while the minimally invasive surgery (MIS) group was defined as the use of lateral interbody fusion and percutaneous posterior screw fixation. The two groups were propensity-score matched to adjust for baseline demographic, surgical, and radiographic characteristics. Data on all disposables and reusable instruments, anesthetic gas, and non-gas medications used during surgery were collected from medical records. The CF of transporting, using, and disposing of each product and the footprint of energy use in operating rooms were calculated. The CF produced was evaluated using the carbon dioxide equivalent (CO2e), which is relative to the amount of CO2 with an equivalent global warming potential. Results: Of the 175 eligible patients, 15 pairs (65 ± 9 years, 47% female) were properly matched and analyzed for all variables. The average CF generated per case was 147.7 ± 37.3 kg-CO2e, of which 54% was attributable to energy used to sterilize reusable instruments, followed by anesthetic gas released into the environment (17%) and operating room air conditioning (15%). Conclusions: The CF generated during ASD surgery should be reduced using a multidisciplinary approach, taking into account that different surgical procedures have different impacts on carbon emission sources.

To assess the characteristics and risk factors for decisional regret following corrective adult spinal deformity (ASD) surgery at our hospital. This is a retrospective cohort study of a single-surgeon ASD database. Adult patients (> 40 years) who underwent ASD surgery from May 2016 to December 2020 with minimum 2-year follow-up were included (posterior-only, ≥ 4 levels fused to the pelvis) (n = 120). Ottawa decision regret questionnaires, a validated and reliable 5-item Likert scale, were sent to patients postoperatively. Regret scores were defined as (1) low regret: 0–39 (2) medium to high regret: 40–100. Risk factors for medium or high decisional regret were identified using multivariate models. Ninety patients were successfully contacted and 77 patients consented to participate. Nonparticipants were older, had a higher incidence of anxiety, and higher ASA class. There were 7 patients that reported medium or high decisional regret (9