Exclusive endoscopic transcanal transpromontorial approach: a new perspective for internal auditory canal vestibular schwannoma treatment.

Babara Masotto,Alessia Rubini,Matteo Alicandri-Ciufelli,Giacomo Pavesi,Livio Presutti,Daniele Marchioni

doi:10.3171/2015.11.jns15952

Abstract

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.

Highlights

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 exclusive endoscopic transcanal transpromontorial approach (EETTA) proved to be successful for the removal of vestibular schwannomas (VSs) or meningioma involving the cochlea, fundus, and internal auditory canal (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

Summary

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. From November 2011 to January 2015, 10 patients underwent surgery using an EETTA to the IAC in the otolaryngology department of the University Hospital of Modena or the University Hospital of Verona. Indications for the use of EETTA included 1) a growing mass consistent with VS and detected on MRI, 2) Koos Grade I (mass located in the IAC) or Koos Grade II (IAC involvement and limited extension to the CPA) tumors (Fig. 1), and 3) American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) Class D hearing status (from severe to profound hearing loss). A cooperating neurosurgeon was present during surgery. A retrospective chart review of patients who had undergone surgery using the EETTA was performed between February and March 2015. All useful data were collected and reported in the present study

Results

Discussion

Conclusion