Endoscopic Repair of Tegmen Defects Via Keyhole Middle Fossa Craniotomy: A Single-Center Case Series

Introduction: Tegmen defects of the temporal bone can lead to cerebrospinal fluid (CSF) otorrhea, encephaloceles, or pneumocephalus, resulting in meningitis, conductive hearing loss, and chronic middle ear effusion. 1 Objective: To evaluate outcomes of an endoscopic mini (keyhole) middle fossa craniotomy (MCF) technique for repair of tegmen defects. Methods: A retrospective single-center chart review of adult patients who underwent endoscopic mini-craniotomy for tegmen repair between December 2021 and July 2025 was performed. Preoperative evaluation included audiometry, high-resolution temporal bone computed tomography (CT), and contrast-enhanced brain magnetic resonance imaging (MRI); beta-2 transferrin was sent selectively. The standardized operative technique included a 2–3 cm extradural temporal keyhole craniotomy, endoscopic inspection (0° and 30°) to identify dural defects, multilayer dural repair (with dural substitute onlay), autologous bone chips and bone pate for tegmen reconstruction, and rotational temporalis flap, with coverage of the cranial defect with a small titanium external ventricular drain (EVD) plate. Lumbar drains were placed in all patients intraoperatively prior to craniotomy. Results: Twenty-four patients (mean age 58.4 ± 13.2 y; range 24–84 y) were included. CSF otorrhea was the most common presenting symptom, seen in 18 patients (75%). Eleven right (46%), 9 (38%) left, and 4 (17%) simultaneous bilateral MCF repairs were performed. Mean operative time was 138.0 ± 66.1 minutes (range 78–383 minutes); mean hospital length of stay (LOS) was 4.96 ± 1.85 days (range 3–11 days). At last follow-up, none of the patients had recurrent symptoms. One patient required removal of hardware for control of an extracranial infection; this was the only significant complication in the series. Three other patients had mild postoperative events. No permanent neurologic deficits occurred postoperatively. Conclusion: Endoscopic keyhole-craniotomy for repair of tegmen dehiscence provides a safe, minimally invasive, and effective approach with favorable operative times, hospital LOS, and clinical outcomes. 2–4 Fig. 1A. Keyhole middle fossa craniotomy. Intraoperative photograph showing the 2 cm keyhole craniotomy exposing the middle fossa floor. The temporalis muscle flap has been reflected superiorly. Fig. 2 Temporal encephalocele. Close-up intraoperative photo demonstrating a temporal lobe encephalocele protruding through a defect in the tegmen. Fig. 3 Repair augmented with external ventricular drain (EVD) plate. Intraoperative photograph demonstrating multilayer repair with EVD plate in place. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany