To observe the location of the balloon on clinical condition and head specimen in the treatment of patients with trigeminal neuralgia by percutaneous microballoon compression (PMC) under conscious sedation and analgesia.

Seven patients with primary trigeminal neuralgia, aged 57-83 years old, four male and three female, from June to August 2019, in the Department of Pain Medicine, the First Affiliated Hospital of Jiaxing University were enrolled in the study. Under the conscious sedation and analgesia and local anesthesia, all cases were treated with PMC guided by CT. The obvious numbness in the area of trigeminal neuralgia was taken as the end standard of operation. After pulling out the balloon catheter, whether there was cerebrospinal fluid overflowing from the puncture needle was observed, and CT scan and three-dimensional reconstruction displayed the position of the balloon. Two open head specimens were punctured and placed with balloon catheter to simulate PMC. After CT scanning, the specimens were dissected to observe the specific location of the balloon.

Seven patients were treated with PMC under CT guided at local anesthesia with conscious sedation and analgesia. After 0.5 ml of iohexol was injected into the balloon, it was filled in an inverted "pear shape" with a small tip and a large bottom, and tightly pressed on the trigeminal nerve impression on the surface of talus cone. When the average compression time reached 238 s, the patient complained of obvious numbness in the original pain area, and the operation ended. Cerebrospinal fluid overflowed from the needle in 2 patients after catheter withdrawal. The effective rate of immediate postoperative analgesia was 100%, and no recurrence was found in 1-3 months follow-up. When two cases of head specimens were treated with puncture and catheterization to simulate PMC, the position and shape of the saccule obtained by CT scanning were consistent with that of clinical condition in vivo PMC. The anatomical specimens showed that the saccule was located between the dura mater and Meckel capsule wall on the lateral side of the trigeminal notch.

PMC can be completed under the local anesthesia with conscious sedation and analgesia, CT guided puncture is more accurate, 3D reconstruction image can directly observe the location of the balloon, which was at trigeminal notch close to the talus cone in the middle cranial fossa. The scene of PMC in vivo can also be reproduced in the simulation of PMC in vitro, the anatomy of the specimen confirmed that the balloon is located in Meckel cave, between the extraluminal wall (dura mater) of Meckel cave and Meckel capsule wall outside the trigeminal notch.

Trigeminal neuralgia; Percutaneous microballoon compression; CT-guided; Anesthesia, local