Comparison of postoperative temporalis muscle atrophy between the muscle-preserving pterional approach and the mini-pterional approach in the treatment of unruptured intracranial aneurysms.

This study aimed to compare the muscle-preserving pterional approach (modified classic pterional approach, mCP) and the mini-pterional approach (mPA) with respect to postoperative temporalis muscle atrophy.From November 2013 to April 2020, 78 patients with unruptured intracranial aneurysm of the anterior circulation underwent surgery using mCP or mPA in our institution. Patients' background characteristics, postoperative complications, and temporalis muscle volume (MV) rates (operative side/healthy side) were retrospectively investigated. In 64 patients (n = 31, mCP group; n = 33, mPA group), excluding 14 patients with missing imaging data from 6 to 24 months after surgery, associations between the MV rate and clinical variables were assessed. A multiple regression model was used to examine the association between the MV rate and the surgical method, which is a predictor of postoperative atrophy.The mCP group had a significantly higher mean MV rate than the mPA group (0.955 ± 0.040 and 0.915 ± 0.070, respectively; p = 0.008). Based on the results of the univariate analysis, a multiple regression model was established using sex, age, follow-up period, and the presence of diabetes in addition to the surgical method. Patients who underwent mCP had a higher MV rate than those who underwent mPA (t value = 2.33, p = 0.023).The present result suggested that mCP has a preventive effect on postoperative temporalis muscle atrophy. However, further studies are needed in order to prove that mCP is also effective in terms of postoperative aesthetic and functional outcomes.