Delayed Facial Palsy Following Microvascular Decompression in Hemifacial Spasm Patients

ABSTRACT

OBJECTIVE: Microvascular decompression(MVD) for hemifacial spasm(HFS) is well established. However delayed postoperative facial palsy has not been substantially reported. The authors reviewed patients with HFS who underwent MVD in our institution to evaluate the post-operative courses with special attention to the development of delayed facial palsy. METHODS: Records of 144 cases(137 patients) from 1988 to 1997 were reviewed. Of these patients, 12(8.3%) developed delayed facial palsy. Follow-ups via chart and phone records were available for 10 of 12 patients. RESULTS: Reviews of these 12 cases demonstrated that 3 men, 9 women of with average age of 53(range 45-60) had delayed facial palsy. Among them, 2 had repeated operation. The preoperative duration of symptoms averaged 12 years(range 1-30) and 4 patients had mild preoperative weakness. All were improved their HFS within 7 days after MVD. Offending vessels were anterior inferior cerebellar artery(AICA) in 7. Five of these were meatal branches and 2 were sandwich type compressions. One case was combined compression of AICA and posterior inferior cerebellar artery. Three to 7 pieces of Teflon felt were necessary for the decompression of offender. The onset of weakness occurred invariably between postoperative day 6 and 11. Two cases had associated complications. The one was hearing loss and the other was meningitis accompanied by cerebrospinal fluid otorrhea. Ten cases received steroids following the onset of their facial palsies. Duration of follow up of 10 cases was 21months(3months-5years). Three cases showed complete recovery at 4, 8 and 12 weeks, respectively. Four patients have improved to House Grade II at 5 weeks and remaining three showed continuing improvement until last follow-up. CONCLUSIONS: Delayed facial palsy following MVD in HFS patients is not uncommon, being 8.3% in our series. It occurs consistently 1-2 weeks postoperatively. Possible causes include facial nerve exit zone injury with Teflon felt or delayed facial nerve edema. Spontaneous recovery usually occur within several weeks.