A Prospective Comparative Cohort Study of Osteoplastic and Conventional Pterional Craniotomy: Operative Technique and Its Impact on Temporalis Muscle Preservation

BACKGROUND AND OBJECTIVES: Temporal muscle atrophy and related cosmetic deformities are common complications after pterional craniotomy. This prospective study compared osteoplastic pterional craniotomy (OPC) and conventional pterional craniotomy (CPC) techniques regarding temporalis muscle volume preservation, frontal branch facial nerve function assessed by eyebrow position, and operative time. METHODS: Forty-six adult patients undergoing surgery for vascular or oncological pathologies requiring a pterional approach were prospectively included. OPC was performed in 16 patients and CPC in 30 patients according to a predefined operative protocol. The primary end point was percentage change in temporalis muscle volume, assessed using MRI-based volumetric analysis preoperatively and at postoperative month 6. Secondary end points included postoperative temporalis muscle volume, frontal branch facial nerve function assessed by eyebrow position, and operative time. Prespecified sensitivity analyses were performed to assess potential period and learning-curve effects. RESULTS: Baseline demographic characteristics were comparable between groups. At postoperative month 6, temporalis muscle volume was significantly better preserved in the OPC group ( P < .001). Percentage change in temporalis muscle volume was 3.45% ± 1.16% in the OPC group and 11.68% ± 2.05% in the CPC group ( P < .001), corresponding to a mean between-group difference of 8.23 percentage points. No significant difference was observed between groups regarding eyebrow drooping. Total operative time was not prolonged in the OPC group and was slightly shorter compared with the CPC group. Sensitivity analyses did not reveal a significant period or learning-curve effect on the primary outcome. CONCLUSION: OPC was associated with superior preservation of temporalis muscle volume, likely related to preservation of muscle attachments, without prolonging operative time. This technique may contribute to improved postoperative temporal contour preservation without compromising surgical efficiency and may represent a feasible option in selected patients, particularly those with high cosmetic expectations or anticipated long-term survival.