Multicenter retrospective observational study. To quantitatively evaluate spinal cord pulsatile motion during anterior cervical decompression and fusion (ACDF) and identify factors affecting spinal cord dynamics. Intraoperative ultrasonography is useful to assess neural decompression during cervical spinal surgery. While spinal cord pulsation has been qualitatively evaluated, detailed quantitative analyses of three-dimensional spinal cord motion are lacking. One hundred nine intervertebral spaces of 50 patients (32 men and 18 women; mean age: 66.9±11.6yr) who underwent ACDF were evaluated. Two-dimensional video measurement software was used to quantify anteroposterior pulsation and craniocaudal sliding motion of the spinal cord in intraoperative ultrasound recordings. In addition, correlations between cervical alignment parameters (C2-7 and O-C2 angles) and spinal cord pulsation characteristics were analyzed. Craniocaudal sliding motion was significantly greater than anteroposterior pulsation in both amplitude (1.09±0.93 vs. 0.34±0.21mm, P <0.001) and velocity (16.75±11.12 vs. 5.39±4.26mm/s, P <0.001). Directional analysis revealed greater velocities from posterior to anterior than from anterior to posterior (5.30±5.12 vs. 4.47±4.12mm/s, P =0.00489) and from cranial to caudal than from caudal to cranial (16.53±11.10 vs. 11.59±7.71mm/s, P <0.001). The maximum anteroposterior amplitude was significantly greater at the C4/5 level than at the C3/4 or C6/7 level ( P =0.0027). The C2-7 angle showed a moderate positive correlation with craniocaudal sliding parameters (amplitude: r =0.467, P <0.001; velocity: r =0.41, P <0.001) and a weak positive correlation with anteroposterior pulsatile parameters. This first quantitative three-dimensional analysis of spinal cord motion during ACDF revealed that craniocaudal sliding motion exceeded anteroposterior pulsation. The preferential direction from cranial to caudal indicated the brain pulsation to be the major origin. The C4/5 level exhibited maximum anteroposterior motion, which may be related to C5 palsy pathophysiology. Increased cervical lordosis promoted both types of motion, particularly craniocaudal sliding. These findings may guide intraoperative neural assessments during cervical decompression procedures.

Retrospective single-center cohort study. To evaluate whether preoperative CT-based finite element analysis (FEA) of vertebral bone modulus predicts bone quality-related complications after lumbar spine fusion. In spine surgery patients, poor bone quality increases the risk of proximal junctional kyphosis/failure, pedicle screw loosening, adjacent segment disease, and pseudoarthrosis, leading to higher revision rates. DXA-based areal bone mineral density (BMD) often fails to identify high-risk patients, particularly in degenerative spines. Three-dimensional CT-based methods, such as Hounsfield units (HU), volumetric BMD, and CT-based FEA, may better capture vertebral mechanical competence by integrating density and microarchitecture. Patients undergoing lumbar fusion at a single academic center in 2017 with ≥2-year follow-up were included (n=85) and classified by the presence of bone quality-related complications. For L1-L5 on preoperative CT, trabecular VOIs were analyzed to obtain mean HU, phantomless-calibrated BMD, and FEA-derived bone modulus. Group differences were assessed with independent-samples t tests, and ROC analysis and multivariable logistic regression examined associations with complication status. Thirty-one patients (36.5%) experienced ≥1 bone quality-related complication; 18 had ≥2 events. Bone modulus was significantly lower in the complication cohort (-15.7% to -23.2%; all p≤0.02), whereas HU and BMD differences were nonsignificant. Bone modulus showed greater ability to distinguish patients with and without complications (AUC 0.65-0.70; all P<0.03), while HU and BMD did not (AUC ~0.57-0.60; all P>0.10). Multivariable models including modulus, BMD, and demographics achieved AUC up to 0.81 at L5 (P<0.001). Preoperative CT-based FEA of vertebral bone modulus outperforms HU and BMD in identifying lumbar fusion patients at risk for bone quality-related complications and may provide a useful adjunct for preoperative risk stratification and surgical planning.

Systematic review and meta-analysis. To conduct a meta-analysis of high-level prospective evidence studies evaluating changes in Visual Analogue Scale (VAS), SI joint pain scores, Oswestry Disability Index (ODI) outcomes, and adverse events (SAE) requiring an additional operation. Low back pain is a leading cause of disability, and the sacroiliac joint (SIJ) is implicated as a primary pain generator in up to 25% of cases. However, SIJ-mediated pain is difficult to diagnose, and is often one of exclusion confirmed by diagnostic injections. Minimally invasive SIJ fusion has emerged as a treatment option for patients with confirmed SIJ dysfunction who fail nonoperative care. A systematic review and meta-analysis were performed according to PRISMA guidelines. Eleven studies (9 prospective cohort and 2 randomized control trials) met inclusion criteria based on study design, quality of evidence, and reporting of patient-reported outcomes. Demographic data, baseline characteristics, surgical indications, and outcomes were extracted. Meta-analyses were conducted to calculate pooled estimates of VAS and ODI improvements, and reoperation rates. Eleven studies reporting on 1,181 sacroiliac joint fusions were included, with a mean follow-up of 27.8 months. Sacroiliac joint pathology was confirmed by diagnostic SIJ injection in 92.7% of patients. Meta-analysis showed a VAS improvement of 45.5 points (95% CI: 38.6-52.3) and an ODI improvement of 23.3 points (95% CI: 21.0-25.7), both exceeding established MCID thresholds (P < 0.001). The meta-analysis of reoperation rates for implant-related serious adverse events was 3% (95% CI: 2%-4%). Minimally invasive SIJ fusion, performed across multiple implant systems and surgical techniques, yields large, clinically meaningful, and reproducible improvements in pain and disability with a low reoperation rate. Outcomes are most favorable when patient selection is rigorous and SIJ dysfunction is accurately identified as the primary pain generator using diagnostic SIJ injection, underscoring the importance of standardized diagnostic pathways in optimizing surgical benefit.

Literature review and international cross-sectional survey with Rasch psychometric analysis. To evaluate the clinical, economic, and operational impact of navigation and robotics in spine surgery by integrating evidence from the best literature and real-world surgeon practice patterns. Robotics and computer-assisted navigation (CAN) are increasingly adopted in spine surgery, with well-documented technical advantages in surgical accuracy and safety. However, their translation into improved patient outcomes, cost-effectiveness, and broad real-world applicability remains uncertain. A scoping review and synthesis of published studies and meta-analyses was performed. In parallel, a 93-item international survey was distributed to spine surgeons across multiple countries, capturing perceptions of accuracy, radiation safety, costs, training, workflow, and patient outcomes. Responses (n = 195) were analyzed using Rasch modeling to assess consensus strength and item difficulty, supplemented by descriptive statistics. Published data and meta-analyses confirm superior screw accuracy with robotics/CAN (≥95% safe-zone placement) and consistent reductions in staff radiation. Real-world surgeon survey responses showed high concordance on these technical benefits but persistent concerns regarding cost (37.4%), equipment availability (55.9%), workflow burden, and limited training access (8.2%). While 74.9% of surgeons anticipated global adoption as standard of care within 10 years, only 52.3% endorsed cost justification. Rasch analysis demonstrated strong consensus on accuracy and complication reduction but skepticism regarding economic viability. Navigation and robotics in spine surgery offer robust technical benefits but remain constrained by cost, training, and workflow barriers. Balanced integration-expanding applications beyond pedicle screw placement, supported by automation, standardized metrics, and scalable financial models-is essential to realize their full clinical and societal value.

Retrospective cohort study. To determine the 5-year incidence and risk factors of radiological adjacent segment disease (R-ASD) and symptomatic adjacent segment disease (S-ASD) after transforaminal lumbar interbody fusion (TLIF) using patient- and segment-based analyses. Adjacent segment disease (ASD) remains a major concern after lumbar fusion surgery. Although previous studies have reported variable incidence rates, differences between R-ASD and S-ASD and segment-specific risk factors remain unclear. Particularly, evidence comparing cranial and caudal adjacent segments after TLIF with uniform mid-term follow-up is limited. Patients who underwent TLIF at two institutions and completed a minimum 5-year follow-up were retrospectively reviewed. The study cohort consisted of 183 patients (mean age, 68.0±9.6y). Patient-based and segment-based analyses were performed. Potential risk factors including demographic variables, and spinopelvic alignment parameters, preoperative adjacent segment status, and surgical interventions at adjacent levels, were evaluated. At 5-year follow-up, patient-based incidence of R-ASD and S-ASD was 31.1% and 18.6%. Segment-based analysis demonstrated that R-ASD occurred more frequently at the cranial segment than at the caudal segment (25.4% vs. 8.1%, P<0.001), whereas S-ASD incidence did not differ significantly. Multivariate analysis identified preoperative disc degeneration (OR 3.13, 95% CI 1.06-9.23) and additional decompression at the adjacent segment (OR 2.42, 95% CI 1.14-5.13) as independent risk factors for cranial R-ASD. Spinopelvic alignment parameters and preoperative foraminal stenosis were not significantly associated with the development of R-ASD and S-ASD. Segment-specific analysis revealed that cranial R-ASD is predominantly influenced by local degenerative changes and surgical intervention rather than global alignment parameters. Careful preoperative assessment of adjacent disc degeneration and cautious postoperative consideration of additional decompression may be important in surgical planning to mitigate ASD development after short-segment TLIF.

Randomized, preclinical animal study. To determine whether exposure to TNF-α levels affects Mesenchymal stem cell (MSC) osteogenic differentiation and if brief, localized TNF-α at the fusion site affects posterolateral arthrodesis in a rat model. Elevated tumor necrosis factor-α (TNF-α) has been shown in degenerative spine pathology, pseudarthrosis, and systemic inflammation. Yet the effect of local localized TNF-α exposure on subsequent arthrodesis remains incompletely understood. MSCs were examined in vitro with TNF-α exposure. Bilateral posterolateral fusions at L4-L5 were performed on 35 Wistar Kyoto male rats. Demineralized bone matrix (DBM) was used for fusion in both groups, but the treatment group also received a low dose of TNF-α (20uL of 50ng/mL) on an absorbable collagen sponge. Animals sacrificed at day 2 and day 4 had the local fusion mass harvested and processed for cytokine analysis with ELISA. Serum was also collected by cardiac puncture. Animals sacrificed at 4 weeks were assessed by manual palpation and microCT for fusion, as well as serum cytokine levels with ELISA. TNF-α suppressed MSC osteogenesis in a dose-dependent manner, starting at 0.1ng/mL. TNF-α protein rose within the fusion mass at postoperative day (POD) 2 in the treatment group compared to controls (P <0.05), while IL-1β levels remained unchanged. At 4 weeks, manual palpation demonstrated fusion in 4/5 control animals, and no fusion in any TNF-α-treated animal (P=0.048). Micro-CT and histological analysis revealed bilateral fusion in 4/5 controls compared with 1/5 TNF-α animals, with the remainder showing unilateral or no fusion (P = 0.286). A brief, localized increase in TNF-α levels after surgery significantly impairs posterolateral fusion in rats. Limiting early TNF-α activity at the fusion site may improve arthrodesis outcomes, particularly in patients with elevated inflammatory profiles.

Finite element (FE) analysis of retrospective clinical cohort. To determine whether preoperative CT-derived FE model outputs can improve subsidence prediction compared to conventional clinical measurements alone in patients undergoing transforaminal lumbar interbody fusion (TLIF). Cage subsidence occurs in approximately 20% of spinal fusion patients and can lead to complications requiring reoperation. While individual risk factors are known, no validated tool integrates patient anatomy, bone quality, and implant characteristics to predict subsidence. Finite element models have been hypothesized to predict subsidence but lack clinical validation. Patient-specific FE models were created from preoperative CT scans of 42 TLIF patients: N=22 Severe subsidence (≥4mm); N=20 Non-severe subsidence (<4mm). Vertebral geometries were segmented, and bone material properties were assigned based on Hounsfield units (HU). Cage positions from postoperative scans were registered to preoperative anatomy. Endplate and trabecular stresses and strains from FE models were compared to clinical measures using receiver operating characteristic analysis. 15 Principal stresses and strains of the FE simulations showed significantly higher values in severely subsided patients compared to the Non-Severe group. Average trabecular intermediate strain achieved the highest area under curve score (AUC=0.809), outperforming all clinical metrics. Peak endplate minimum principal stress (AUC=0.775) was the second-best FE classifier. Traditional clinical measures showed lower discriminative ability: cage length (AUC=0.797), cage width (AUC=0.750), and cage height (AUC=0.698). Patient-specific FE model outputs significantly correlate with clinical subsidence outcomes and outperform several traditional metrics in classifying severe subsidence. Both endplate and trabecular stresses and strains are important predictors, with average values showing comparable or superior performance to peak values. Integration of FE models into the clinical workflow could provide a comprehensive preoperative subsidence prediction tool.

Retrospective Cohort. This study aimed to: (1) compare opioid use between primary and revision fusion patients; (2) evaluate differences in non-opioid analgesic use; and (3) identify risk factors of long-term opioid consumption. Preoperative opioid exposure and revision surgery are recognized risk factors for prolonged postoperative opioid use after lumbar fusion, yet long-term data remain limited. Patients who underwent elective 1-3 level lumbar spine fusion between were retrospectively identified and chart reviewed (2018-2023). Opioid and non-opioid prescription data was extracted from the state prescription drug monitoring program (PDMP) at 30 days, 90 days, 1 year, and 2 years. Patients were stratified into primary versus revision fusion cohorts and compared using bivariate and multivariable analyses. A total of 1,938 patients were analyzed (1,498 primary, 440 revision). Revision patients had greater preoperative opioid morphine milligram equivalent (MME) burden (953 vs. 334, P<0.001). Postoperatively, opioid use rates were similar through 30 days, but revision patients demonstrated higher MME use at 90 days (428 vs. 219, P<0.001), 1 year (1,142 vs. 382, P<0.001), and 2 years (1,550 vs. 497, P<0.001). Gabapentinoid use was also higher in revision patients beginning at 90 days (19.3% vs. 13.4%, P=0.003). Multivariable regression confirmed preoperative MME as the strongest risk factor of long-term opioid burden. Revision status was independently associated with higher MME use at 1 year (β=348.3, P=0.011) and 2 years (β=964.4, P<0.001), but not at 90 days. Revision lumbar fusion patients demonstrate a greater pre- and postoperative opioid burden, and a greater postoperative gabapentinoid burden. Multivariable analysis confirms revision status as an independent risk factor of greater long-term MME use, beginning at 1 year. Together these findings suggest a complex, possibly neuropathic pain phenotype in revision patients, underscoring the need for tailored perioperative counseling and consistent long-term, multidisciplinary pain management.