Extended Pericranial Flap for Anterolateral Skull Base Reconstruction after Frontotemporal Orbitozygomatic Transcavernous Approaches: Operative Technique and Nuances

Introduction: Technical advances in neurosurgery over the past several decades have allowed for the safe resection of deep and invasive skull base lesions previously deemed inoperable. Frontotemporal orbitozygomatic approaches are useful for resecting parasellar and cavernous sinus lesions. Meningiomas and other dural-based lesions arising from this region often require extensive dural resection and bone removal leading to a significant risk for cerebrospinal fluid leakage. Pericranial flap reconstruction has become a popular method for reconstructing skull base defects due to its autologous nature, ease of harvesting, and natural vascular pedicle. However, the lateral extent of the pericranium ends at the superior temporal line (STL) and the surface area is somewhat limited when using a frontotemporal curvilinear incision.

Methods: The authors present a novel technique for extending the size of the pericranial flap laterally past the STL by incorporating the loose areolar layer below the temporoparietal fascia.

Results: The galea is elevated from the pericranium in the usual fashion with sharp dissection, keeping the plane of dissection close to the galea to maximize the thickness of the graft. When the STL is encountered, the temporoparietal fascia, which is continuous with the galea, is elevated from the underlying loose areolar tissue and superficial temporalis fascia and this dissection is continued down to the lateral aspect of the incision. The pericranium is cut and elevated starting medially until the STL is encountered. Instead of truncating the graft at the STL, sharp dissection is used to elevate the loose areolar tissue and a partial thickness of superficial temporalis fascia, to maximize graft thickness. Laterally as the temporalis fascia divides, the superficial temporalis fascia is elevated in continuity with the graft. Thus a continuous graft is elevated consisting of pericranium medial the the STL and loose areolar tissue and temporalis fascia lateral to the STL. Partial thickness temporalis fascia is left over the temporalis muscle to aid in closure and cosmesis. A vascular pedicle can be left either at the supraorbital artery or the superficial temporal artery depending on the required direction of graft rotation. The surface area of the pericranial flap can also be increased by undermining the galeal layer medially and posteriorly, if needed.

Conclusion: Extending the pericranial graft laterally past the STL is a simple technique that proves useful when large dural defects are anticipated after frontoteporal orbitozygomatic approaches. The senior author has performed this technique on over 100 orbitozygomatic approaches without incidence of postoperative CSF leakage. The surgical technique and operative nuances are demonstrated.