MVD procedure steps – Patient is placed in lateral position, and a curved incision of approximately 4 to 125 px in length is made at the level of the external auditory canal; – Bone drilling is exposed, and a bone window is formed, 2×50 px in size; – Brain plate is retracted to open the superior lateral cerebellum, and the CPA pool is fully drained of fluid. - Exploration along the lateral cerebellum towards the deep side, sharp separation of the arachnoid, careful protection of the facial auditory nerve, and preservation of the rock vein as much as possible. - Adjust the depth of the microscope, sharply separate the arachnoid, clearly expose the trigeminal REZ and its surrounding vessels, carefully identify the responsible vessels, mostly arteries, most commonly SCA, followed by AICA, sometimes basilar artery, and even PICA; occasionally venous compression, the veins are most commonly branches of the rock vein. - The arachnoid membrane between the nerve and the vessel is fully released, and Teflon cotton of appropriate size is placed between the two. MVD surgical outcome Immediate outcome – Early surgical results are achieved when the patient is awake from anesthesia and the facial pain disappears, with most reports reporting an immediate efficiency of 90-95%. - A small number of patients continue to have varying degrees of pain for several weeks after surgery, which resolves within 2-8 weeks. Long-term outcome – Theodosopoulos: In 420 patients, 87% had complete remission after surgery, with an overall efficiency of 98%. The mean follow-up was 4.7 years, and 93% improved significantly. Postoperative recurrence – Postoperative recurrence mostly occurred within the first 1 to 2 years after surgery, with a recurrence rate of less than 2% at 5 years after surgery and less than 1% at 10 years after surgery, and an excellent rate of 85% could still be achieved after reoperation after recurrence. Factors affecting the long-term outcome after MVD surgery – whether the pain is relieved immediately after surgery, if the pain is not completely relieved 2 weeks after surgery, it predicts that the pain is prone to recurrence in the near future. - Those with arterial compression in the trigeminal nerve REZ are less likely to recur, and those with no intraoperative arterial compression or those whose compression vessel is a vein have a high recurrence rate postoperatively. - Patients with a history of less than 7 years have a good surgical outcome, and those with a history greater than 7 years are prone to recurrence. - Women are prone to recurrence. - Multi-branch involvement is less effective than single involvement, but is not related to lateralization. - Previous history of trigeminal nerve surgery is also an influential factor in long-term outcome. Those who had previous trigeminal nerve radiofrequency thermocoagulation, trigeminal nerve rhizotomy or with sensory impairment had poor results. Reasons for recurrence of symptoms after MVD – Failure to identify the responsible vessel intraoperatively or inadequate decompression. - Embolization of the ethmoid sinus and obstruction of venous return, causing new venous compression. - Arachnoid adhesions at the trigeminal REZ or formation of new adhesions postoperatively. - Improper placement or displacement of the isolate. Treatment principles of trigeminal neuralgia Initial onset is preferred to drug treatment. Surgery is considered when conservative treatment is ineffective. - MVD is preferred for those who are physically fit and the patient agrees. – Radiofrequency thermocoagulation or gamma knife treatment can be considered for those who cannot tolerate open surgery.