Symptomatic mass effect of a hypertrophied pericranial flap after repair of a dural defect: case report.

Objective: To detail a potential complication of the use of vascularized pericranial flaps in the repair of dural defects, namely, flap hypertrophy secondary to venous engorgement.
Clinical Presentation: A 23-year-old man with a left parietal lobe hemangiopericytoma underwent a craniotomy for tumor resection. The resultant dural defect was repaired with a vascularized pericranial flap. On postoperative Day 3, the patient developed headache, confusion, aphasia, and right upper extremity apraxia. Imaging revealed an extra-axial collection at the craniotomy site; on reexploration, a swollen, engorged pericranial flap causing mass effect was found.
Intervention: The pericranial flap was excised.
Conclusion: In this case, hypertrophy of the vascularized pericranial flap is hypothesized to have occurred because of venous congestion, possibly secondary to restriction of venous outflow by the overlying bone flap.