Strategy for dealing with unfamiliar and thick vessels during microvascular decompression: A first case report of hemifacial spasm caused by a persistent primitive trigeminal artery.

Rationale: A persistent primitive trigeminal artery (PPTA) is a rare embryonic cerebrovascular anomaly. Hemifacial spasm (HFS) refers to involuntary contractions of facial muscles caused by the compression of blood vessels against the root exit zone of the facial nerve. There have been no reported cases of PPTA causing neurovascular contact and HFS. Microvascular decompression surgery effectively treats HFS, but operating on strong PPTA vessels poses challenges. We aim to introduce a more efficient approach for overcomes these difficulties and facilitates surgery.

Patient Concerns: A 44-year-old male patient without any underlying medical conditions presented to our hospital with involuntary movements of the left side of his face accompanied by numbness in the left maxilla (V2 area).

Diagnosis: Brain magnetic resonance imaging and magnetic resonance angiography showed that PPTA was in contact with the left facial nerve.

Interventions And Outcomes: Following a retro-sigmoid craniotomy, we attempted to interpose the facial nerve and the PPTA as an offender vessel, but the decompression was not sufficient. However, after transposing the vessel using the proximal Teflon transposition with interposition technique, the strength of the involuntary movements was reduced. Following surgery, there was no more lateral spreading response, and the patient symptoms improved.

Lessions: In cases where the vessel causing HFS is particularly strong and thick, the proximal Teflon transposition with interposition technique for transposition may be advantageous. This method could simplify and enhance the efficacy of microvascular decompression, without compromising the quality of surgical outcomes.