Surgical Treatment And Prognostic Analysis Of Primary Hemifacial Spasm

Objective: To investigate the outcomes,complications and recurrence of microvascular decompression(MVD)for primary hemifacial spasm(pHFS)and to identify any prognostic factors.We focus on the influence of the morphology of posterior fossa on the surgical effect.Methods: The clinical data of 131 patients with pHFS who received MVD treatment from January 2015 to December 2017 in neurosurgery department Tongji hospital,Huazhong University of Science and Technology were retrospectively analyzed.Among them,76 patients with complete clinical data were included in this study.Magnetic resonance imaging was used to measure the length,width and height of the posterior fossa,we calculate the ratio of length to height,the ratio of length to width and the ratio of width to height,and use ellipsoid approximation method to calculate the volume of the posterior fossa.The effects of gender,age,affected side,interval between onset and surgery,surgical position,responsible vessel,degree of compression,volume of posterior fossa,anatomical morphology of posterior fossa on postoperative complications,efficacy and recurrence were analyzed.Results: The average age of the 76 patients was 48.5±9.3 years,and the ratio of male to female was 1:1.7.10 cases showed no apparent neurovascular compression(NVC)while 66 cases showed obvious NVC.Among them,the responsible vessels were anterior inferior cerebellar artery(AICA)in 24 cases,posterior inferior cerebellar artery(PICA)in 23 cases,and basilar artery or vertebral artery in 9 cases.All patients were treated with MVD,and postoperative complications were observed in 9 patients,with an incidence of 11.8%.Complications were cerebrospinal fluid leakage in 2 cases(2.6%),poor wound healing in 1 case(1.3%),delayed facial paralysis in 1 case(1.3%),facial paralysis and hearing loss in 1 case(1.3%),partial/complete hearing impairment in 4 cases(5.2%),and no death.All patients were followed up for 24.0±8.3 months,and the effective rate was 81.6%.Patients' age,gender,affected side,interval between onset and surgery,surgical position,responsible vessel had no effect on surgical complications,efficacy or recurrence.Posterior fossa height(p=0.006),ratio of length to height(p=0.03),ratio of width to height(p=0.005)and degree of compression(p=0.002)were significantly correlated with poor postoperative outcomes.Compared with the effect group,the ineffective group had a relative flatter posterior fossa.Conclusion: MVD is effective in treating pHFS,relatively flat posterior cranial fossa and weak NVC suggest poor outcomes.