Robot-assisted stylomastoid foramen puncture and radiofrequency ablation for hemifacial spasm treatment: clinical outcomes and technique assessment.

Objective: Stylomastoid foramen (SMF) puncture with radiofrequency ablation (RFA) is a minimally invasive therapy for hemifacial spasm (HFS) with notable therapeutic outcomes. Conventionally, this procedure is performed under CT guidance. The present study highlights the authors' preliminary clinical experience with robot-assisted SMF puncture in 7 patients with HFS using a neurosurgical robot.

Methods: Patients were secured in a skull clamp, and their heads were linked to the Sinovation neurosurgical robot's linkage arms for precise positioning. Bone fiducial registration was conducted using the robotic pointer. Under robotic guidance, a puncture needle was positioned at the skin entry point and then advanced to the target with a surgical blade incision. On target attainment, an RFA electrode was positioned, and the ablation was performed while monitoring facial nerve function. Preoperative and postoperative spasm grading, surgical metrics, and adverse events were meticulously documented.

Results: The puncture trajectories averaged 49.5 mm in length, and the overall operation duration was 27.3 minutes. Guided by the robotic arm, all puncture attempts were successfully achieved without any obstructions, and SMF puncture was completed in a single attempt. Following RFA, immediate spasm relief was achieved, with all patients attaining Cohen spasm grade 0. Over a mean follow-up period of 12 months (range 6-15 months), no recurrence of spasms was reported. Facial paralysis was observed in 85.7% of patients, with 6 cases classified as House-Brackmann (HB) grade II and 1 case as grade III. At the final follow-up, 1 patient remained at HB grade II, while the remaining patients improved to grade I. No other lasting or severe complications were recorded.

Conclusions: SMF puncture and RFA emerge as a potent and minimally invasive treatment option for HFS. The robot-assisted approach, despite necessitating additional time for head fixation and registration, notably reduces the overall puncture time, puncture attempts, and radiation exposure, thereby enhancing the puncture success rate.