OBJECTIVE: The aim of this study was to describe the first case series in which an exclusive endoscopic transcanal transpromontorial approach (EETTA) was used to treat small vestibular schwannomas (VSs) and meningiomas of the internal auditory canal (IAC). METHODS: The authors performed a retrospective review of patients who had undergone surgery using an EETTA to the IAC at 2 university tertiary care referral centers during the period from November 2011 to January 2015. RESULTS: Ten patients underwent surgery via an EETTA for the treatment of VS in the IAC at the University Hospital of Modena or the University Hospital of Verona. The patients had Koos Grade I or II tumors and American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) Class D hearing status preoperatively. Gross-total resection was achieved in all patients. No major complications such as cerebrospinal fluid leakage or hemorrhage were reported. In 7 of 10 (70%) patients, facial nerve function was normal immediately after surgery (Rough Grading System [RGS] Grade I). Two patients presented with a transitory facial palsy immediately after surgery (RGS Grade II–III) but experienced complete recovery during the follow-up period. The mean follow-up was 10 months. CONCLUSIONS: The EETTA proved to be successful for the removal of VS or meningioma involving the cochlea, fundus, and IAC, with possible lower complication rates and less invasive procedures than those for traditional microscopic approaches. The potential for the extensive and routine use of this approach in lateral and posterior skull base surgery will depend on the development of technology and surgical refinements and on the diffusion of skull base endoscopic skills among the otolaryngological and neurosurgical communities.

Background: Surgical treatment of lesions involving the temporal bone, petrous apex, or internal auditory canal is usually performed using the classical microscopic approach that necessitates wide external incisions and soft tissue dissection. At present, the main application of endoscopic surgery is in the surgical treatment of middle ear cholesteatoma, but with the natural evolution of the technique, there will be an increasing number of applications in lateral skull base surgery. Objective: This study aimed to describe the pilot clinical experiences of our institution with combined microscopic/endoscopic-assisted approaches to the lateral skull base. Methods: A retrospective chart review was performed on patients undergoing an operation between July 2005 and September 2011 for lateral skull base pathology using the endoscope-assisted technique. Results: Nine patients (7 female, 2 male; mean age = 57.4 years) were reviewed and included in the present study. In all cases, the petrous apex lesion of each patient was unilateral: 6 cases had cholesteatoma of the petrous bone; 2 cases had cholesterinic granuloma of the petrous apex; and 1 case had a low-grade chondrosarcoma of the petrous apex. Overall, after a mean follow-up of 30.7 months, no residual disease has been found in our series up to the present time in the cholesteatoma group. In the cholesterinic granuloma group, only a partial success was obtained in the patient who underwent the infracochlear approach, since the most medial part of the pathology was not accessed and still persisted at neuroradiologic examinations made postoperatively. Conclusion: In our case series, lateral combined microscopic/endoscopic procedures have proved to be effective in the treatment of petrous apex lesions, allowing less destructive approaches compared to exclusive microscopic procedures.