2026 Poster Presentations
P231: ENDOSCOPIC REPAIR OF TEGMEN DEFECTS VIA KEYHOLE MIDDLE FOSSA CRANIOTOMY: A SINGLE-CENTER CASE SERIES
Shriya Airen, MD; Samuel I Spicher, BS; Lee S Hwang, MD; Pamela C Roehm, MD, PhD; St. Luke's University Health Network
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 effusion1.
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.
Conclusions: Endoscopic keyhole-craniotomy for repair of tegmen dehiscence provides a safe, minimally invasive, and effective approach with favorable operative times, hospital LOS, and clinical outcomes2,3,4.
Keywords: tegmen defect; CSF otorrhea; encephalocele; endoscopic; keyhole craniotomy; middle cranial fossa
Figure 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.
Figure 2. Temporal encephalocele.
Close-up intraoperative photo demonstrating a temporal lobe encephalocele protruding through a defect in the tegmen.
Figure 3. Repair augmented with external ventricular drain (EVD) plate.
Intraoperative photograph demonstrating multilayer repair with EVD plate in place.
References:
1. Braca JA III, Marzo S, Prabhu VC. Cerebrospinal fluid leakage from tegmen tympani defects repaired via the middle cranial fossa approach. J Neurol Surg B Skull Base 2013;74(02):103–107
2. Roehm PC, Tint D, Chan N, Brewster R, Sukul V, Erkmen K. Endoscope-assisted repair of CSF otorrhea and temporal lobe encephaloceles via keyhole craniotomy. J Neurosurg. 2018;128(6):1880–1884.
3. Adkins WY, Osguthorpe JD. Mini-craniotomy for management of CSF otorrhea from tegmen defects. Laryngoscope. 1983;93(8):1038–1040.
4. Adil SM, Zachem TJ, Hatfield JK, Abdelgadir J, Hoang K, Codd PJ. Keyhole mini-craniotomy middle fossa approach for tegmen repair: a case series and technical instruction. J Neurol Surg Rep. 2025;86(1):e19–e23.