In the last decade, computational fluid dynamics (CFD) has shown valuable application in the field of vascular neurosurgery. Although earlier studies showed higher values of wall shear stress in neurovascular conflict, hemodynamic patterns in the blood vessel after microvascular decompression are unknown. This study aimed to analyze the hemodynamic features of the offending artery preoperatively and postoperatively using computational fluid dynamics.

We performed a retrospective study of 11 consecutive patients undergoing endoscopic decompression of trigeminal neuralgia at the Department of Neurosurgery, Fujita Health
University Bantane Hospital. The patient data were de-identified before analysis. Basic demographic data and neurologic admission status were collected.
Analyzed radiological findings including location and site of neurovascular conflict, and identification of offending vessel. Barrow Neurological Institute Pain Scale (BNI-PS) was
used to analyze the pain intensity pre-operatively and postoperatively. Hemoscope software (Amin, Ziosoft Corporation, Minato ward, Tokyo, Japan) was used to process images from 11 patients who underwent microvascular decompression. Pressure (P), wall shear stress (WSS) gradient and vectors, normalized WSS, and streamlines (SL) direction and velocity were assessed.

This analysis included 11 patients with a median age of 71 years (54.5 % female). Superior Cerebellar Artery (SCA) was the most common offending vessel. Comparing the values of WSS on the three measured parts of the blood vessel using CFD, we noticed that the area of neurovascular contact had the highest WSS mean 2.8 Pa (IQR 2.4-4.43 Pa). In addition, we observed a decrease in WSS in the area of neurovascular contact postoperatively (p=0.003).

Although there were high WSS preoperatively, we noticed that a lower WSS was observed postoperatively, in addition to a postoperatively better BNI pain score, especially in the area
of neurovascular decompression. CFD could serve as an additional diagnostic tool in preoperative planning, as well as for evaluating the treatment outcome. The utility of CFD in
the recurrence of TN cases should be investigated.