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Microvascular depression treatment for hemifacial spasm possibly as effective with, without BAER monitoring, data suggest

Tuesday, September 30 2008 | Comments

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What's This? Microvascular depression (MVD) without neurophysiological monitoring is a safe and effective treatment option in patients with hemifacial spasm (HFS) when modern microsurgical techniques are combined with experience in treating the condition, a retrospective study suggests.

A retrospective chart review was conducted of data from 114 first-time MVD surgeries for HFS performed by a single surgeon with substantial experience in the surgery without the use of intraoperative brainstem auditory evoked response (BAER) monitoring. None of the patients had experienced HFS as a result of a tumor, arteriovenous malformation, or aneurysm.

Postoperative outcomes were determined by reviewing records and through telephone interviews. At least 1 year of postoperative follow-up data were available for 91 of the 114 patients, and the median follow-up in all cases was 8 years (range, 3 months to 23 years).

There were no major deficits (including brainstem infarctions or complications that required further operation) or cases of operative mortality. Complications included 1 case of postoperative deafness, 1 of permanent subtotal hearing loss, and 2 of transient hearing loss. Also, 10 patients experienced delayed facial palsy, 2 cases of which had not completely resolved at last follow-up.

In the patients who experienced an initial spasm-free postoperative period, time to failure was the midpoint between the previous clinical contact at which the patient did not experience spasms and the first contact at which the patient reported spasm recurrence. The same method was used to estimate when patients became spasm-free. The Kaplan-Meier estimate of the proportion of spasm resolution was 80% within 1 year of surgery (95% CI, 73%-88%), 85% within 5 years (95% CI, 78%-92%), and 86% within 10 years (95% CI, 79%-93%).

"Successful outcomes were remarkably durable," the study authors noted.

Among the patients who experienced complete relief of HFS symptoms at any point after MVD, 96% and 93% had no spasms at 1 year and at 5 years, respectively (95% CI, 87%-99%). Seventeen patients were considered nonresponders or surgical failures, as they experienced at least some residual spasms at latest follow-up.

These outcomes compared well with those reported in studies in which investigators used intraoperative monitoring, the authors said, but they noted that their results indicate that BAER monitoring may not always be necessary for this procedure.

"Although BAER monitoring may be a valuable adjunct to surgery at centers experienced with the modality, the absence of intraoperative monitoring should not prevent neurosurgeons from performing MVD in patients with HFS," they concluded. (Dannenbaum M, et al. J Neurosurg 2008; 109:410-415.)

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