Postoperative temporalis muscle atrophy and the use of electrocautery: a volumetric MRI comparison.

Postoperative temporalis muscle atrophy from injury to the neurovascular supply can cause significant cosmetic disfigurement, and avoidance of electrocautery use has become a common practice in minimizing this outcome. We attempted to quantify the effects of electrocautery on temporalis atrophy by retrospectively reviewing postoperative magnetic resonance images in patients having undergone an orbital frontal craniotomy. We reviewed medical records and compared volumetric measurements of the temporalis muscle in 25 patients using the contralateral temporalis muscle as an internal control. The mean size of the nonsurgical temporalis muscle was 24.6 cm(3) as compared with 23.6 cm(3) on the operated side. The difference of 1.0 cm(3) was not statistically significant (p = 0.32). The only postoperative atrophy noted visually on the magnetic resonance images developed in the posterior superior aspect of the temporalis muscle, behind the vertical incision of the temporalis muscle. In the small control group, with known injury to V3, the mean nonsurgical size was 27.7 cm(3), whereas it was 16.5 cm(3) on the contralateral surgical side. The difference of 11.2 cm(3) was statistically significant (p = 0.04). These findings suggest that the use of electrocautery to dissect the temporalis muscle does not significantly contribute to atrophy provided careful surgical technique is practiced.