El-Gohary, Mohamed M.

OBJECTIVE Multisegmental pathological autofusion is a hallmark feature of ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH), creating a rigid, brittle spine highly susceptible to three-column fractures and devastating neurological injury. This study aimed to evaluate survival outcomes in this patient population and identify clinical and demographic predictors of mortality. METHODS Adults with DISH or AS who sustained a fracture and were admitted to a single tertiary care center for spinal fracture were retrospectively identified using ICD-10 diagnostic codes. Data were extracted on demographics, clinical presentation, fracture characteristics, and details of treatment. RESULTS A total of 383 patients (median age 78 years, 75.2% male) were included. Over a median follow-up of 17.3 months, overall mortality was 38.1%, in-hospital mortality was 5.2%, 30-day mortality was 5.7%, and 1-year mortality was 18.0%. Initial treatment consisted of external orthosis in 220 (57.4%) and surgery in 144 (37.6%), while 19 (5.0%) were left untreated. Patients who died were older (median 83 vs 74 years, p < 0.001), had a lower BMI (29.4 vs 32.3 kg/m 2 , p < 0.001), had higher frailty on the 5-item modified frailty index (mFI-5), and more commonly had congestive heart failure (CHF), cancer, functional dependency, and chronic kidney disease (CKD) (all p < 0.01). Mortality was not associated with fracture location, mechanism of injury, fracture number, or the presence of neurological deficits. Univariable time-to-event analysis showed that decreased survival was predicted by older age (HR 1.08, p < 0.0001), lower BMI (HR per kg/m 2 0.93, p < 0.0001), functional dependency (HR 2.05, p < 0.001), cancer (HR 1.55 p = 0.01), CKD (HR 1.48, p = 0.019), CHF (HR 2.18, p < 0.001), and higher mFI-5 score (HR per point 1.34, p < 0.001). On multivariable analysis, older age (HR 1.06 per year, p < 0.001), lower BMI (HR per kg/m 2 0.95, p < 0.001), and mFI-5 score (HR per patient 1.37, p < 0.001) remained significant independent predictors of mortality. Treatment modality did not predict mortality. CONCLUSIONS AS- or DISH-associated spinal fractures have a high associated mortality, regardless of mechanism or severity. Treatment modality did not affect odds of survival, suggesting that nonoperative management with an external orthosis may be an appropriate option, particularly in older and medically complex patients.

Background/Objectives: To identify predictors of successful fusion and adjacent segment disease (ASD) following ALIF. Methods: Records of patients undergoing one- or two-level ALIF were queried for baseline and postoperative radiographic data, demographics, operative notes, and implant characteristics. All had ≥1 year of follow-up with CT, and multivariable Cox regression was used to identify predictors of radiographic fusion through the interbody, ASD, and ASD requiring reoperation. Results: In total, 177 patients (median 59 yr; 52.5% male) were treated at 245 unique levels, of which 193 fused (81.3% with posterior fixation and 59.6% with standalone), 43 had ASD (17.6%), and 14 had ASD requiring reoperation (5.7%). Fusion was predicted by anterior cage placement (HR 0.94/mm; 95% CI [0.90, 0.98]; p = 0.003) and BMP use (HR 1.92; [1.15, 3.18]; p = 0.012). Radiographic ASD was predicted by older age (HR 1.08 per year; [1.03, 1.14]; p < 0.001), undergoing a revision [vs. index] fusion operation (HR 3.51; [1.44; 8.59]; p = 0.006), lower preoperative disc height (HR 0.83/mm; [0.74, 0.94]; p = 0.003), and preoperative facet vacuum phenomenon (HR 2.46; [1.18, 5.15]; p = 0.017). None of the extracted variables predicted reoperation for ASD. Conclusions: BMP use along with anterior cage placement and posterior fixation may improve the odds of fusion through the interbody following one- or two-level ALIF. Adjacent segment pathology is more common in patients with greater preoperative degenerative pathology (vacuum sign; more collapsed disc) and advanced age. Pelvic fixation did not improve fusion odds, but the data highlight the benefits of supplementary posterior fixation vs. standalone ALIF.

OBJECTIVE Achieving submillimetric accuracy in stereotactic neurosurgery remains critical for safely targeting deep brain structures. Current workflows rely on intraoperative CT to register stereotactic frames to preoperative imaging, but this introduces additional radiation exposure, cost, and workflow complexity. Three-dimensional surface scanning (3DSS) potentially offers a fast radiation-free alternative capable of capturing detailed craniofacial anatomy and frame geometry. Therefore, the aim of this cadaveric study was to evaluate the feasibility, accuracy, and navigational compatibility of integrating 3DSS into stereotactic workflows as a potential replacement for intraoperative CT. METHODS A human cadaveric head was imaged with both thin-slice CT and structured-light 3DSS after mounting stereotactic frame components. CT, 3DSS, and computer-aided design (CAD) models were registered using a multistep point cloud alignment pipeline involving the fast point feature histogram, the random sample consensus method, and the iterative closest point algorithm. Accuracy was assessed using surface deviation error, root mean square error (RMSE), and fiducial registration error within a commercial neuronavigation platform. RESULTS Fusion of the 3D facial scan with CT provided a mean surface deviation error of approximately 0.4 mm. Registration of the 3DSS-derived N-bar localizer to its CAD reference model produced a frame alignment RMSE of 1.3 mm. Within the navigation system, the 3DSS-based workflow achieved a mean fiducial registration error of 0.14 mm (range 0.02–0.20 mm), outperforming the conventional CT-based method (mean error 0.20 mm, range 0.09–0.40 mm). CONCLUSIONS The 3DSS-based method enabled precise submillimetric stereotactic registration without the need for intraoperative CT, reducing radiation exposure and operative complexity. This workflow is fully compatible with existing navigation systems and could serve as a practical radiation-free alternative in stereotactic neurosurgery. Future work will focus on automating frame detection, incorporating artificial intelligence–driven fusion methods, and validating this approach in live surgical settings.