Temporal Bone Encephalocele Repair – Our Experience

Background: Presentations of encephalocele of temporal bone can range from an incidental finding in asymptomatic patient to a life threating meningitis in a CSF otorrhea patient. Literature is replete with different surgical techniques for management of these varied patients. Autologous materials like fat, muscle, fascia, bone, cartilage and alloplasts like bone cement etc. have been used to repair the tegmen defects. The main aim of our study was to review all the cases of temporal bone encephaloceles surgically managed in our institution. We present the etiologies, approaches along with the tegmen repair technique used in our series.

Study Design: Retrospective case series in Tertiary referral center for Otology, Neurotology and Skull Base surgery

Methods: We reviewed charts of all the patients who underwent temporal bone encephalocele repair from October 2009 to September 2013 in our institute. Data on patient demographics, clinical presentation, etiopathology, approach, technique of repair and complications was recorded.

Results: From October 2009 to September 2013, 58 patients underwent surgical repair of temporal bone encephalocele.The follow up ranged from one month to 48 months with an average of 21 months. The age range was 6yrs to 78 years. with average being 49.9yrs.There were 22 males and 36 females. The common etiologies were cholesteatoma, trauma, and idiopathic CSF otorrhea. Depending upon the site of the defect 31 patients underwent middle cranial fossa approach, 13 had trans mastoid approach and 14 had combined approach. The middle fossa tegmen repair technique included a layer of thick alloderm on the floor of the middle cranial fossa, placed in an extradural fashion followed by the contoured bone flap as a firm repair. Finally another layer of alloderm was placed on the dural side extending onto the lateral surface of the temporal lobe dura. Titanium mesh was used to reconstruct the craniotomy defect. Only one patient had transient facial palsy (HB Grade 2) which completely resolved in 48 hours. There were no other complications. None of the patients required any further operative interventions.

Conclusion: Surgical repair of skull base defect is the only option to manage temporal bone encephaloceles. The defect can be approached via mastoid or middle cranial fossa depending on the location, size of defect, preoperative auditory function and concomitant pathology. The repair of tegmen defect using bone flap and alloderm is a novel technique with negligible complication.