Microvascular reconstruction of the skull base: a clinical approach to surgical defect classification and flap selection.

Skull-base tumor resection and reconstruction produce a major physiologic and anatomic impact on the patient. At our institution, the use of vascularized, free-tissue transfer has replaced pedicled flaps as the preferred modality for reconstructing complex cranial base defects involving resection of dura, brain, or multiple major structures adjacent to skull base, including the orbit, palate, mandible, skin, and other structures. The goals of reconstruction are to: (1) support the brain and orbit; (2) separate the CNS from the aerodigestive tract; (3) provide lining for the nasal cavity; (4) re-establish the nasal and oropharyngeal cavities; (5) provide volume to decrease dead space; and (6) restore the three-dimensional appearance of the face and head with bone and soft tissues. Surgical management requires a multidisciplinary effort with collaborating neurosurgical, head and neck, and plastic surgical teams. Successful reconstruction of skull base defects is predicated upon a careful appreciation of the specific region. Defects may be classified based on their anatomic location and loss of volume, support, and skin cover. Free flaps provide reliable, well-vascularized soft tissue to seal the dura, obliterate dead space, cover exposed cranial bone, and provide cutaneous coverage for skin or mucosa.