Introduction: Hemifacial spasm (HFS) is a condition of debilitating, involuntary contractions of facial muscles with an estimated prevalence of 11/100,000. The potentially curative microvascular decompression surgery (MVD) aims to alleviate compression upon the facial nerve root entry zone (fREZ) by mobilizing culprit vessels and maintaining them off the nerve with implant material. Surgery is undertaken in less than 10% of sufferers across North America, such that few centres have a concentrated volume of MVD experience. We examined the operative findings and outcomes of repeat surgery after failed MVD for HFS.
Methods: A database of over 700 MVDs performed by the senior author was reviewed to identify patients undergoing repeat surgery for HFS where the original surgery was performed elsewhere. Intraoperative findings were obtained from operative reports and diagrams. Outcomes were determined from hospital records and telephone questionnaires.
Results: Twelve HFS patients were identified and all were found to have persisting vascular compression on the fREZ not identified or alleviated at initial surgery. In 2 cases the prior implant material was found in the region of the fREZ but not alleviating the culprit vascular compression. In 9 cases there was no evidence of exploration or implant material at the fREZ but rather more distally on the cisternal portion of the nerve. In 1 case, there was no evidence of any implant material. Repeat surgery was successful in decompressing the fREZ in all 12 cases and postoperatively all improved. At a mean follow up of 64 months (3-180), 10 patients reported complete resolution of spasms, 1 reported >75% and another >50% spasm reduction. No patients had major permanent complications, although 1 patient had new onset of mild facial weakness and 1 patient developed aseptic meningitis with subsequent full resolution of symptoms.
Conclusions: Failure of MVD to cure HFS is related to inadequate identification and alleviation of vascular compression upon the affected fREZ. Repeat surgery was successful at a high-volume centre.
Patient Care: Clinicians and patients are often faced with a difficult decision in cases of failed microvascular decompression for Hemifacial Spasm. Our research provides support for repeat surgery in cases of failed MVD for Hemifacial Spasm.
Learning Objectives: By the conclusion of this session, participants should be able to 1) Describe the anatomical target for microvascular decompression for HFS
2) Identify common sources of treatment failure in MVD for HFS 3) Discuss treatment options for patients with failed MVD