P.022 Hemifacial Spasm due to dolichoectatic vertebrobasilar artery compression
Bibliographic record
Abstract
Background: Hemifacial Spasm (HFS) is rarely caused by a dolichoectatic vertebrobasilar artery (eVB) compression of the Facial Nerve. This can pose a surgical challenge when performing microvascular decompression as vessel mobilization is often difficult due to atherosclerosis, tethering from brainstem perforators, and large size. These patients are often not considered for surgery. Methods: A retrospective chart review of patients who were surgically treated by the senior author between 2003 and 2017 with an admitting diagnosis of HFS was performed. Patients with preoperative neuroimaging demonstrating eVB compression of their facial nerve/root were included. Results: During the 15-year review, 315 patients underwent microvascular decompression for HFS and 21 (6.7%) had dolichoectactic vertebrobasilar compressions. At final followup (>3 months) 19 patients (90.4%) experienced reduction in symptoms with 15 (71.4%) having complete resolution. One patient required re-operation and benefitted from subsequent symptom relief. The majority of culprit compression was found proximally on the pontine surface. Mobilization of the culprit vessel was achieved successfully in the majority of cases with Teflon pledgets. There were no perioperative strokes or death. Complications are presented Conclusions: Microvascular Decompression for Hemifacial Spasm caused by dolichoectatic vertebrobasilar artery compression can be performed with a high rate of safety and success in the setting of a high case volume centre.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.012 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".