Expanded Transcanal Transpromontorial Approach: A Novel Surgical Technique for Cerebellopontine Angle Vestibular Schwannoma Removal

Abstract

Objective Vestibular schwannoma (VS) is a benign tumor of the lateral skull base. Different microscopic surgical techniques are described in literature: the retrosigmoid and translabyrinthine approaches are used to treat big tumors located in the cerebellopontine angle, and the middle cranial fossa approach is utilized for small tumors with good hearing preservation. The expanded transcanal transpromontorial (ExpTT) approach is a combined microscopic-endoscopic technique previously indicated for Koos stage I and II VS and now proposed for larger VS, up to 3 cm in diameter, with linear progression into the cerebellopontine angle and touching the brainstem. Study Design The study was a retrospective case series of patients who underwent ExpTT surgery for VS in our ear, nose, and throat department. Setting We reviewed the surgical videos and electrophysiologic data recorded during the surgical operations. Subjects and Methods From January 2015 to January 2017, 20 patients affected by Koos stage II and III VS underwent surgery in our department with the ExpTT approach. This novel technique is described step by step, with a focus on the surgical procedure and anatomic landmarks; outcomes are detailed in terms of early and late complications. The mean follow-up was 15 months. Results The ExpTT approach permitted, in all patients, gross total resection of the tumor without any complication and with preservation of facial nerve function. All patients had a good postoperative recovery. Conclusion The ExpTT technique is a new approach that combines the advantages of a microscopic technique with the ones offered by the endoscope in removal of VS.

Surgical Landmarks of the Endoscopic Transcanal Transcochlear Approach: A Cadaveric Study

“…Presutti et al (16) concluded that expanded ETTA (using both endoscope and microscope, which allows bimanual dissection of the tumor and therefore, enhanced control of the surrounding neurovascular structures) was successful in the management of 10 patients with vestibular schwannoma Koos stage I or II with no facial dysfunction in the last follow-up. Marchioni et al (9) described the expanded ETTA for the successful resection of vestibular schwannoma in patients with Koos grade II and III with no complication and good facial nerve result and concluded that this technique was a new approach that combined the advantages of a microscopic technique with the ones offered by the endoscope. Moon et al (12) evaluated a modified ETTA with no EAC closure for the treatment of vestibular schwannomas and reported better cosmetic outcome compared to the original technique with total resection of the tumor in all cases.…”

“…The lower risk of CSF leakage is because the ETTA is minimally invasive and with limited bone removal (9). The ETTA not only could minimize post-surgery complications but also could be a cost-benefit technique because it could shorten postoperative intensive care unit recovery and hospital stay (9,11).…”

“…(2). Also, in a recent case series of 20 patients, the transcanal transpromontorial approach was used successfully for the removal of vestibular schwannoma (9).…”

Intralabyrinthine Schwannomas: Disease Presentation, Tumor Management, and Hearing Rehabilitation

“…When further dissection was needed for the ETTA approach, a blind sac of the EAC was performed. 18,36…”

Transmeatal microsurgery for intralabyrinthine and intrameatal schwannomas: a reappraisal

“…The few reports on the transmeatal approach to acoustic schwannoma are reported in Table I 4,[6][7][8][9][10][11][12][13] . The endoscopic surgery of the middle ear recently evolved into the transcanal endoscopic approach to labyrinth and IAC for schwannoma with good outcomes [14][15][16] . It is universally acknowledged that the endoscope allows excellent visualisation of structures and hidden sites "around the corner".…”