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Objective: Although well-established in moyamoya disease (MMD), the role of direct superficial temporal artery (STA) to middle cerebral artery (MCA) bypass in non-MMD (N-MMD) cerebrovascular steno-occlusive syndromes remains controversial. Nonetheless, the recurrent stroke risk in patients with N-MMD, despite best medical management, remains exceedingly high-especially for those suffering from hypoperfusion-related ischemia. The study objective was to determine the relative safety and efficacy profiles of direct STA-MCA bypass surgery for MMD and N-MMD patients in a large contemporary cohort., Methods: The authors conducted a retrospective review of all direct STA-MCA bypass cases performed between 2014 and 2023 at a high-volume center, which yielded 139 cases. Cases were excluded if they involved double-barrel bypass, an interposition graft, or if the surgical indication was not cerebral hypoperfusion. Direct bypass graft patency was serially assessed on follow-up vessel imaging., Results: Of the 139 included cases, 88 (63.3%) were MMD and 51 (36.7%) were N-MMD cases. The mean patient age was 49.2 years and 60.4% were female. The mean follow-up duration was 18.5 months. The perioperative stroke risk within 30 days of revascularization was 6.5% for the overall cohort, with no significant difference (p = 0.725) observed between MMD (5.7%) and N-MMD (7.8%) cases. The overall postoperative ipsilateral hemispheric and MCA distribution stroke rates at last follow-up were 11.5% and 9.4%, respectively. Despite a greater medical comorbidity burden, N-MMD cases demonstrated comparable rates of direct bypass graft occlusion (21.6% N-MMD vs 28.4% MMD, p = 0.426), MCA-distribution ischemic stroke (11.8% N-MMD vs 7.9% MMD, p = 0.549), and ipsilateral ischemic stroke (15.7% N-MMD vs 9.1% MMD, p = 0.276) to patients with MMD at last follow-up. Higher preoperative total hemispheric flow on noninvasive optimal vessel analysis (NOVA) imaging was the only variable associated with prolonged direct bypass graft patency (hazard ratio [HR] 0.39, p = 0.036). Postoperative stroke-free survival was improved by performing dural synangiosis (HR 0.31, p = 0.033) and, in multivariate analysis, was reduced with direct bypass graft occlusion (HR 4.58, p = 0.009) and a preoperative diffusion-weighted imaging-Alberta Stroke Program Early CT Score (DWI-ASPECTS) < 8 (HR 3.90, p = 0.024)., Conclusions: This robust cohort of MMD and N-MMD STA-MCA bypass cases highlights the safety and efficacy of a technically sound direct bypass across all subtypes of cerebrovascular steno-occlusive disease. Careful attention to preoperative MRI parameters, including hemispheric flow rates on NOVA imaging, may improve surgical risk stratification. Further examination of the benefits of adjunctive indirect bypass or dural synangiosis, especially for patients with N-MMD, remains warranted.

Objective: Skull base chordomas are rare, locally osseo-destructive lesions that present unique surgical challenges due to their involvement of critical neurovascular and bony structures at the craniovertebral junction (CVJ). Radical cytoreductive surgery improves survival but also carries significant morbidity, including the potential for occipitocervical (OC) destabilization requiring instrumented fusion. The published experience on OC fusion after CVJ chordoma resection is limited, and the anatomical predictors of OC instability in this context remain unclear., Methods: PubMed and Embase were systematically searched according to the PRISMA guidelines for studies describing skull base chordoma resection and OC fusion. The search strategy was predefined in the authors' PROSPERO protocol (CRD42024496158)., Results: The systematic review identified 11 surgical case series describing 209 skull base chordoma patients and 116 (55.5%) who underwent OC instrumented fusion. Most patients underwent lateral approaches (n = 82) for chordoma resection, followed by midline (n = 48) and combined (n = 6) approaches. OC fusion was most often performed as a second-stage procedure (n = 53), followed by single-stage resection and fusion (n = 38). The degree of occipital condyle resection associated with OC fusion was described in 9 studies: total unilateral condylectomy reliably predicted OC fusion regardless of surgical approach. After lateral transcranial approaches, 4 studies cited at least 50%-70% unilateral condylectomy as necessitating OC fusion. After midline approaches-most frequently the endoscopic endonasal approach (EEA)-at least 75% unilateral condylectomy (or 50% bilateral condylectomy) led to OC fusion. Additionally, resection of the medial atlantoaxial joint elements (the C1 anterior arch and tip of the dens), usually via EEA, reliably necessitated OC fusion. Two illustrative cases are subsequently presented, further exemplifying how the extent of CVJ bony elements removed via EEA to achieve complete chordoma resection predicts the need for OC fusion., Conclusions: Unilateral total condylectomy, 50% bilateral condylectomy, and resection of the medial atlantoaxial joint elements were the most frequently described independent predictors of OC fusion in skull base chordoma resection. Additionally, consistent with the occipital condyle harboring a significantly thicker joint capsule at its posterolateral aspect, an anterior midline approach seems to tolerate a greater degree of condylar resection (75%) than a lateral transcranial approach (50%-70%) prior to generating OC instability.

Introduction: In this study we sought to evaluate the reproducibility of sensory nerve conduction studies (NCS) using ultrasound-guided needle positioning (USNP)., Methods: Orthodromic NCS of the sural nerve using needle electrodes with USNP as well as surface electrodes were conducted twice in 20 healthy volunteers., Results: The mean sensory nerve action potential (SNAP) amplitude in the initial examination was 39.5 μV using needle electrodes with USNP, and 12.5 μV using surface electrodes (P < 0.0001). The mean SNAP amplitude in the follow-up examination was 39.2 μV using needle electrodes with USNP, and 12.4 μV using surface electrodes (P < 0.0001). The mean intraindividual change in SNAP amplitude (test-retest) was 21.2% using needle electrodes with USNP, and 24.8% using surface electrodes (P = 0.6)., Conclusions: Sensory NCS of the sural nerve using needle electrodes with USNP have reliable test-retest reproducibility and yield greater SNAP amplitudes than sensory NCS using surface electrodes., (Copyright © 2011 Wiley Periodicals, Inc.)