Endaural Subtemporal Approach for Middle Fossa Encephalocele and CSF Leak Repair

Idiopathic temporal bone meningoencephalocele with CSF leak is most often treated via middle fossa craniotomy and dural repair with good results. This approach provides wide exposure of the middle fossa floor and temporal lobe dura. However, in cases of focal tegmen dehiscence, adequate exposure for encephalocele resection and repair of CSF fistula can be obtained through a keyhole craniotomy and cosmetically favorable endaural incision. We present three patients successfully treated for idiopathic temporal bone encephalocele with CSF leak via an endaural subtemporal (EAST) keyhole craniotomy.

Each patient presented with unilateral tegmen defect with CSF otorhinorrhea and imaging findings consistent with temporal encephalocele. All surgeries were done by a team consisting of a neurotologist and neurosurgeon. Incision was made from the anterior-superior border of the tragus progressing superiorly and posteriorly along the superior border of the helix. A vertical limb of the incision was planned, but not needed ([Fig. 1]). Temporalis fascia was harvested during the approach. An ~2.5 cm craniotomy was performed under microscopic visualization ([Fig. 2]). The temporal dura was elevated off the middle fossa floor and any encephaloceles were cauterized and transected. The contents were removed from the temporal bone whenever feasible and sent for pathology.

Once all tegmen defects were visualized, the dura overlying the inferior temporal gyrus was opened sharply. Any connections at the sites of encephaloceles were cauterized and cut. A rolled sheet of DuraMatrix was then placed under the temporal lobe and unrolled to cover the dural defects. This was sutured into place with the primary closure of the dura. The previously harvested temporalis fascia was then placed over the tegmen defects in the epidural space. Fibrin glue was used to secure the fascia in place and cover the dural suture line. The bone flap was then replaced using titanium plates. The incision was then closed with absorbable suture with good cosmetic outcome ([Fig. 3]).

All patients tolerated the procedures well and were discharged from the hospital in 2 to 3 days. Postoperative CT scans were obtained and showed no complications. All patients had resolution of their CSF leaks. The authors feel that this approach offers a cosmetic incision with adequate exposure for subtemporal keyhole craniotomy. This approach has proven to be adequate for management of temporal encephaloceles, though further work is ongoing to determine its utility for additional intracranial pathology.

Fig. 1 Planned incision. Posterior vertical limb was not required for any case.

Fig. 2 Planned keyhole craniotomy.

Fig. 3 Postoperative incision.

Publication History

Article published online:
01 February 2023