A Clinical Study Of The Corelation Between Hemifacial Spasm And The Pressure Of Neurovascular Compression At Facial Nerve REZ

Objective:To investigate the clinical correlation between the severity of HSF and the pressure of neurovascular compression(N VC)at facial nerve REZ during the microvascular decompression(MVD).Methods:We conducted a prospective study of 52 patients with primary hemifacial spasm who met our eligibility criteria and underwent microvascular decompression from October 2015 to September 2016.We classified the preoperative spasm severity according to the Cohen’s scores.Codman intracranial pressure(ICP)monitoring system was utilized to measure the pressure between the offending vessel and the facial nerve at the REZ during the MVD surgery,to explore the clinical correlation between the hemifacial spasm severity and the pressure of NVC at the REZ.All the patients who recruited into our study were followed up for 12-24 months.The data were analyzed with the corelated statistical method.Results:In 52 cases,male/female ratio was 0.625:1(20:32),and the mean age was 49.1(28–73).The mean of HFS duration was 4.48±4.553 years(range,1–240 months).The cure rate of the MVD surgery was 100% in the all 52 HFS patients,and no failed cases were recorded among the current study populations.42/52(80.77%)patients were immediately cured and 10/52 patients(19.23%)presented a delayed relief,while all of them were relieved completely within 1–11 months post-surgery.The mean of the Cohen’s scores(1–4)was 2.62±0.889,while the means of the pressure of NVC that corresponded to the Cohen’s scores(1–4)were 23.00±1.83,34.91±12.42,46.50±9.40,and 55.40±3.03 mmHg,respectively.The intraoperative pressure readings of NVC were in the range of 21–63 mmHg and the average was(41.52±1.87mmHg).With Spearman rank correlation,there was a positive,significant and strong correlation stated between the pressure of NVC and the Cohen’s scores(r=0.689,p<0.0001).The simple linear analysis indicated that sex(p=0.676),the duration(p=0.304)and delayed relief(p=0.158)were not associated significantly with the pressure of NVC.Additionally,a substantial correlation was determined between the pressure values and the time until the complete recovery(r=0.949,P<0.0001)of the delayed healing population.However,there was a poor correlation between the pressure of NVC and age(r=0.282,p=0.043).Conclusion:(1)The severity of HFS exhibited a strong positive correlation with the intraoperative offending vessel’s pressure values.(2)There maybe determining the lowest threshold pressure of the NVC which symptoms start to appear in HFS patients.(3)Neurovascular pressure is an important factor in pathogenesis of Hemifacial spasm.