[Efficacy of CT-guided percutaneous stylomastoid foramen puncture through the mandibular angle approach and radiofrequency ablation of facial nerve for the treatment of hemifacial spasm].

Objective: To investigate the efficacy of CT-guided percutaneous mandibular angle radiofrequency thermocoagulation (RFT) of facial nerve through stylomastoid foramen for the treatment of hemifacial spasm. Methods: A total of 82 patients with primary facial spasm who underwent CT-guided RFT in the Department of Pain Medicine of Zhejiang Integrated Traditional Chinese and Western Medicine Hospital and Department of Pain Medicine of the First Hospital of Jiaxing from January 2019 to June 2021 were retrospectively analyzed, including 27 males and 55 females, aged 24-85 (59±11) years. All patients were divided into three groups according to the different puncture approaches: anterior mastoid approach group (Group A, n=35), posterior mastoid approach group (Group P, n=25) and mandibular angle approach group (Group M, n=22). The puncture time, the minimum stimulating current inducing the twitch of facial muscles on the affected side, the temperature at the end of RFT and the duration of RFT at this temperature, the total treatment time, as well as the degree of facial paralysis and complications 1 day after operation were compared among the three groups. Results: The puncture time of the Group A, Group P and Group M was (31.0±4.9) min, (31.9±6.5) min and (35.3±5.9) min, respectively, and the difference was statistically significant (P=0.020). The puncture time of the Group M was longer than that of the Group A and P (both P<0.05). The minimum stimulation current inducing the twitch of the affected facial muscle in the three groups was (0.5±0.2) mA, (0.4±0.1) mA and (0.3±0.1) mA, respectively, with a statistically significant difference (P=0.000). The minimum stimulation current in the Group M was less than that in the Group A and P (both P<0.05). The temperature at the end of RFT of the three groups was (78.6±8.1) ℃, (76.6±8.3) ℃ and (67.0±8.4) ℃, respectively, and the difference was statistically significant (P<0.001). The temperature of the Group M was lower than that of the Group A and P (both P<0.05). There were no significant differences among the three groups in the duration of RFT at the final temperature, the total treatment time, and the degree of facial paralysis 1 day after operation (all P>0.05). No hematoma, infection, hearing impairment and other complications occurred in all patients. Conclusion: CT-guided percutaneous RFT through stylomastoid foramen is efficacious in the treatment of hemifacial spasm, and the mandibular angle approach provides better performance.