Purely Endonasal Endoscopic Approaches for Extracranial Trigeminal Nerve Schwannoma

Abstract

The aim of this study is to assess the effectiveness and safety of purely endonasal endoscopic resection of extracranial trigeminal schwannomas (TGSs), with assessment of surgical and clinical outcomes in order to identify optimal candidates for an endonasal endoscopic approach (EEA). Methods: A retrospective review of patient's records operated for TGSs between 2008 and 2021 was conducted. Patients operated with a purely EEA were included in this study. Pictures from a frozen fresh cadaver head dissection were used to demonstrate the surgical approach and to show anatomic relationships, complexity of the surgical area and safe corridors for surgery.Results: A total of 5 patients (4 females and 1 male) were operated for TGS. All patients had facial numbness (100%) as a presenting symptom, followed by facial pain in 2 patients (40%), and orbital pain in 1 (20%). Also, 3 patients (60%) had a tumor originating at the level of the foramen ovale and 2 (40%) at the foramen rotundum. The mean tumor diameter was 3,7 ± 2 cm. Gross total resection were achieved in all cases. Postoperatively, 1 patient had severe mastication problems, 1 had blurred vision, and in the long-term follow-up, 1 had frontal sinusitis. The mean follow up was 106.6 (min:49, max:132, SD: 29.82) months. No recurrences were detected. Conclusions: In cases with the extradural TGS having limited extension into Posterior Cranial Fossa, or located in the Middle Cranial Fossa, a purely EEA is possible even for tumors bigger in size. Unilateral endonasal corridors are adequate for resection in most cases.

Endoscopic Endonasal Approach for Trigeminal Schwannomas: Tailored Approaches Based on Lesion Traits

“…In our study, for all the type E3 and derived subtypes, we adopted the trans‐prelacrimal recess approach with or without the assisted trans‐Meckel's cave approach to achieve GTR. The same results were also obtained in previous reports; for example, Zhang et al, 31 Taylor et al, 32 Shi et al, 11 and Başak et al, 12 published several small series treated by the transpterygoid approach or translateral pterygoid plate approach. Compared with those approaches, the most significant advantage lies in the protection of the nasal structures by the trans‐prelacrimal recess approach.…”

“…In recent years, endoscopic surgery has emerged as an entirely new technique for the removal of TS and has achieved continuous improvement in clinical results, regardless of whether using the endoscopic transorbital approach, 4,5 endoscopic endonasal approach (EEA), 2,6–12 or endoscopic transvestibular transmandibular approach 13–15 . However, an endoscopic transorbital approach cannot be adopted for TS predominantly involving the posterior fossa.…”

“…Although the endoscopic transvestibular transmandibular approach is suitable for tumors in the V3 division, it will be limited if the tumor is accompanied by a notable extension into the middle and posterior fossae 13 . Conversely, EEA surpasses the aforementioned constraints and has been reported in each type of TS, both in terms of anatomic study and clinical cases 6–12,16,17 . However, to our knowledge, there is no large series on the efficacy of EEA for TS, nor is there any literature that systematically describes all the specific subapproaches for tumors at different locations.…”

“…Especially for TSs extending into multiple fossae, it is often necessary to expand the scope of surgery, which has nonnegligible tissue trauma and may lead to approach-related morbidities. 3 In recent years, endoscopic surgery has emerged as an entirely new technique for the removal of TS and has achieved continuous improvement in clinical results, regardless of whether using the endoscopic transorbital approach, 4,5 endoscopic endonasal approach (EEA), 2,[6][7][8][9][10][11][12] or endoscopic transvestibular transmandibular approach. [13][14][15] However, an endoscopic transorbital approach cannot be adopted for TS predominantly involving the posterior fossa.…”

“…13 Conversely, EEA surpasses the aforementioned constraints and has been reported in each type of TS, both in terms of anatomic study and clinical cases. [6][7][8][9][10][11][12]16,17 However, to our knowledge, there is no large series on the efficacy of EEA for TS, nor is there any literature that systematically describes all the specific subapproaches for tumors at different locations.…”