T present the excision of acoustic neuromas and other tumors of the cerebellopontine angle (CPA) is based on three surgical approaches. The suboccipital approach is rapidly performed, but demands that the patient be placed in a lateral, sitting, or semisitting position. This exposes the patient to the possi- bility of air embolism and above all, direct retraction of the cerebellum, which is potentially traumatizing, particu- larly if the tumor is large. 6,16,38 The suboccipital approach frequently causes considerable and persistent postopera- tive headache associated with cervicalgia. 16,37 However, most neurosurgical teams still use this approach because it permits all types of tumors, regardless of size, to be ex- cised without automatically sacrificing the hearing func- tion. 2,3,13,14,25,28,30,36 The middle cranial fossa approach is a route to the inter- nal auditory meatus (IAM) and its contents via its roof 22 and is essentially an extradural approach. An enlarged middle cranial fossa approach allows the surgeon to open the roof of the CPA after dissection of the superior petro- sal sinus to excise tumors protruding from the internal acoustic porus. 18,38,39,54 Technically, it is a difficult ap- proach and hemostasis in the inferior part of the CPA is a delicate procedure. Furthermore, the retraction of the tem- poral lobe, even extradurally, is not without risk, especial- ly in elderly patients. The translabyrinthine approach has led to the formation of otoneurosurgical teams. 4,9,17,23,34,46 The surgical exposure of the CPA via this route does not require direct retrac- tion or compression of the cerebellum and brainstem, 9,26 and defects of the facial nerve trunk can be managed by its transposition or transplantation. The principal disad- vantage of this approach is the inevitable sacrifice of labyrinthine function caused by more accurate localiza- tion of the facial nerve, and above all the loss of a degree of surgical safety, which predominates over the other purely functional considerations. 6,9,46 The main drawback in the development of the translabyrinthine route is the risk of a cerebrospinal fluid (CSF) fistula resulting from the opening of the temporal bone air cell system, which is in contact with the cistern of the CPA. 9,15,31 Our experience with the use of fibrin glue over a 10-year period has dem- onstrated a considerably reduced risk of CSF leak, to less than 4%. 4,12 J Neurosurg 86:812–821, 1997 812 The widened retrolabyrinthine approach: a new concept in acoustic neuroma surgery VINCENT DARROUZET , M.D., JEAN GUERIN, M.D., NAAMAN AOUAD, M.D., JAROMIR DUTKIEWICZ, M.D., ALEXANDER W. BLAYNEY , F.R.C.S., AND JEAN-PIERRE BEBEAR, M.D. Departments of Otorhinolaryngology and Neurosurgery, University Hospital of Bordeaux, Bordeaux, France; and Department of Otorhinolaryngology, The Mater Hospital, University College Dublin, Dublin, Ireland  For many years, the retrolabyrinthine approach has been limited to functional surgery of the cerebellopontine angle (CPA). As a result of the increased surgical exposure, particularly the opening of the internal auditory meatus (IAM), the widened retrolabyrinthine technique permits tumor excision from both the CPA and the IAM, regardless of the histologi- cal nature of the tumor. The authors have treated 60 acoustic neuromas of varying sizes via this approach (6% intrameatal tumors; 30%  25 mm in diameter). The postoperative mortality rate was 0%. The risk of fistula formation was 3.3%, and 3.3% of the patients suffered from postoperative meningitis. The results for facial nerve function were equivalent to those obtained previously via a widened translabyrinthine approach and those in a series treated via a suboccipital approach (80% with Grades I and II, 15% with Grade III, and 5% with Grades V and VI). One patient (1.7%) required a secondary hypoglossal–facial nerve anastomosis and had attained a Grade IV result 6 months later. Postoperatively 21.7% of these patients maintained socially useful hearing and 20% had mediocre hearing. Socially useful hearing was preserved in 50% of a subgroup of 20 patients who had both good preoperative hearing and a tumor that involved less than half of the IAM regardless of its volume. Additionally, 15% had mediocre hearing that could be improved with hearing aids. Because of its efficacy in preserving hearing, the authors favor the retrolabyrinthine over the occipital approach, with the latter being considered less subtle and more aggressive. KEY WORDS • acoustic neuroma • retrolabyrinthine approach • cerebellopontine angle • cerebrospinal fluid fistula • hearing preservation A J. Neurosurg. / Volume 86 / May, 1997