Technical Nuances of Temporal Muscle Dissection and Reconstruction for the Pterional Keyhole Craniotomy

Introduction: The supraorbital (SO) keyhole approach offers limited access for aneurysms located at the MCA bifurcation with long M1 segments or distal MCA aneurysms. Alternative minimally invasive routes centered on the pterion have been developed to address these aneurysms. Appropriate dissection and reconstruction of the temporal muscle (TM) are important for optimal exposure and best cosmetic results with the pterional keyhole craniotomy (PKC).

Methods: The authors describe the technical nuances of TM dissection and reconstruction adapted to the PKC.

Results: After incising the scalp in a curvilinear fashion behind the hairline, an interfascial dissection is performed, allowing anterior reflection of the superficial temporal fat pat and superficial temporal fascia (STF). The TM is incised 1.0 cm below its insertion at the superior temporal line. The deep temporal fascia (DTF) and TM are incised vertically, completing a “T” shape incision. Subperiosteal dissection of both TM flaps preserves the deep temporal arteries and nerves. A craniotomy measuring 3 cm × 3 cm is cut above the pterion. Dissection of the Sylvian fissure and of the MCA aneurysms proceeded without the use of retractors. The bone flap and associated hardware is entirely covered by the TM, which is reconstructed in two layers: the TM/DTF and the STF.

Conclusion: This dissection technique prevents damage to branches of the facial nerve and minimizes TM damage. Dividing the TM in half and reflecting both parts anteriorly and posteriorly prevent suboptimal illumination and visualization under the microscope. Covering the bone flap and related hardware with a multilayer anatomical reconstruction optimizes cosmetic results.