A novel method for autograft placement during tegmen repair: the suture "pull-through" technique.

INTRODUCTION Temporal bone encephaloceles and cerebrospinal fluid (CSF) leaks are associated with an increased risk of life-threatening intracranial infection. Defects in the floor of the middle cranial fossa are attributed to prior infection, trauma, iatrogenic injury, and increased intracranial pressure. In the temporal bone, intracranial contents most commonly pass through dehiscences in the tegmen tympani and mastoideum, and hearing loss can be a presenting symptom from CSF effusion or herniating brain abutting the ossicular chain. Defects over the posterior fossa have been reported but are considerably more rare. Not all bony defects of the middle cranial fossa floor are associated with a meningoencephalocele or CSF leak, but surgical repair of temporal bone encephaloceles, with or without a CSF leak, is generally pursued when these lesions are identified. The size and location of a tegmen defect can dictate the most appropriate surgical approach. In solitary lateral lesions, either a transmastoid or a middle cranial fossa approach may provide adequate visualization for repair. The combined transmastoid-subtemporal middle cranial fossa approach for CSF fistula and encephalocele repair is commonly employed for large or medial tegmen defects, particularly those that involve the epitympanum and an intact ossicular chain. A variety of materials can be used to repair a defect, with an autologous multilayer reconstruction being preferred to a single layer or use of synthetic substrate. Optimal multilayer graft placement is tedious given the narrow corridor afforded by the middle fossa approach, especially when a limited craniotomy is combined with dynamic (nonfixed) temporal lobe retraction. We present our preliminary results using a novel modification to the standard middle fossa floor reconstruction technique, utilizing a composite autologous graft that is positioned with a suture “pullthrough.” We believe that this method allows the graft to be reliably centered over the defect, even through a small craniotomy.