Introduction: In patients without preoperative LSR diagnosis is solely based on clinical symptoms and intraoperatively no baseline comparison is available. Hence this often leads to difficulty not only to diagnose but also to define the adequate decompression intraoperatively resulting in confusion regarding end of the surgery. We evaluated the surgical outcomes of our patients who underwent MVD for hemifacial spasm without preoperative LSR and intended to define the significance of LSR in EMG performed in patients with HFS.
Methods: We underwent MVD for HFS but had absence of LSR on preoperative EMG between 2012 and 2014. And then we retrospectively reviewed surgical outcomes were evaluated at 48 hours, 1 and 12 months after surgery. Follow-up facial EMG was performed 3 months after surgery.
Results: Total 844 patients underwent MVD for HFS. And among them, LSR did not appear on preoperative EMG in 29(3.4%) patients. 19 patients (65.5%) were female and 10 patients were male. The mean age was 51.9 years. Preoperative brain MRI showed probable offending vessels compressing root exit zone of facial nerve. And we confirmed these offending vessels intraoperatively. The symptoms did not disappear in thirteen cases immediately following MVD, while two (6.8%) patients complained symptoms at 12 months after surgery. No patients experienced recurrence of spasm and no abnormal waves were reported on follow-up facial EMG.
Conclusions: Although LSR did not appear on preoperative EMG, if the patient presented with typical symptoms and offender vessels could be appreciated definitely in MRI, we can expect good results after MVD for HFS. Also, no statistical significance could be obtained regarding the difference between surgical outcomes of patients with and without preoperative LSR which indicates that in patients with HFS, preoperative EMG recording serves as a confirmatory tool for diagnosing spasm in a patient with clinical symptoms rather than a definitive tool.
Patient Care: outcome improvement of MVD
Learning Objectives: Meaning of LSR