Pennington, Zach

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.

OBJECTIVE Intramedullary spinal cord tumors (IMSCTs) are typically treated with maximal safe resection, during which neurosurgeons often monitor for neurological injury using muscle motor evoked potential (mMEP) and direct wave (D-wave) neuromonitoring. The predictive value of changes in D-waves for identifying motor outcomes is underexplored. This study evaluated the utility of D-waves for predicting postoperative motor deficits. METHODS Patients who underwent resection of a primary IMSCT with mMEP neuromonitoring from 2003 to 2023 at a tertiary care hospital were identified. Patients who underwent D-wave monitoring in addition to mMEP monitoring were compared to those who underwent mMEP monitoring alone using the Mann-Whitney U-test, chi-square test, and Fisher’s exact test. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of D-wave and mMEP monitoring for identifying new neurological deficits immediately postoperatively and at 1 month, 6 months, and last follow-up were calculated. RESULTS After matching, 125 patients were included (median age 42.0 years; 57.6% male; median follow-up 34.0 months), of whom 88 had both mMEP and D-wave data. The most common pathologies were ependymoma (64.0%) and astrocytoma (17.6%). Patients who did and did not undergo D-wave neuromonitoring had similar preoperative neurological function, primary pathology, tumor grade, and tumor location. D-wave use was associated with increased gross-total resection (88.6% vs 64.9%, p = 0.002) and reduced mortality (5.7% vs 24.3%, p = 0.007), length of stay (5.0 vs 6.0 days, p = 0.033), and 30-day readmission (2.3% vs 13.5%, p = 0.013) and reoperation (1.1% vs 10.8%, p = 0.012). At the 6-month follow-up, D-wave monitoring alone was superior to mMEP and combination monitoring for detecting new motor deficits. D-wave monitoring had peak sensitivity (77.8%) and NPV (96.5%) at 6 months and peak specificity (95.8%) and PPV (76.9%) in the immediate postoperative period. CONCLUSIONS D-wave monitoring was associated with reduced mortality and was more accurate than mMEP monitoring alone or combination monitoring for detecting new postoperative neurological deficits. Further prospective studies are needed to validate these results.