Varied patterns of postoperative course of disappearance of hemifacial spasm after microvascular decompression

Summary Background. The precise course of resolution of postoperative residual HFS after a single MVD has not been well categorised quantitatively in the literature. Not all patients with HFS were cured immediately after a single MVD; some of them exhibited a gradual disappearance of the HFS over a period of time. The time course of the gradual resolution of HFS is categorised and the situation of re-exploration in a few patients whose HFS persisted or recurred is determined.Methods. The results of 547 MVDs in 545 Chinese patients were reviewed using the database from the authors personal records between January 1992 and December 2002. Different outcomes were observed and divided into four categories according to the variable convalescent period: type 1, spasm cured immediately; type 2, spasm persisted with milder severity and faded away gradually from 7 days to as long as 2 years; type 3, spasm ceased immediately but recurred after 3 days and ran the same course as in type 2; type 4, failed.Findings. Four hundred and seventy-nine patients followed a type 1 course, which constituted an 87.9% immediate success rate. Forty-one patients (7.5%) followed a type 2 course, including three whose spasm persisted for more than 2 years. Twenty-three patients (4.2%), including one with venous compression, followed a type 3 course with their spasm ceased within three months. All of them had typical vascular loop compression. Another patient with a venous contact failed to respond positively to the first MVD underwent re-operation within 2 months. Re-operation was also performed in one patient four days after the first MVD due to persisting and even more severe spasm. These two patients were categorized type 4 as they failed the first MVD (0.4%). Late recurrence was noted in five patients from 1 to 2 years after the first MVD, only one of whom underwent re-exploration and was then cured again.Conclusions. Approximately 80% of the patients with HFS achieved immediate excellent results after a single MVD, the rest of the patients exhibited residual but usually milder spasms, which resolved gradually over a period of time. According to the patterns of the residual or persisting spasms, the situation and timing of re-exploration can be determined without difficulty. The surgeon should be concerned about missing the responsible vessels in patients with typical HFS who completely failed the first MVD.