Madjid Samii1, Maysam Alimohamadi, Venelin Gerganov. 1. *International Neuroscience Institute, Hannover, Germany; ‡Iranian International Neuroscience Institute, Brain and Spinal Injury Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Abstract
BACKGROUND: Trigeminal schwannomas are the most common intracranial nonvestibular schwannomas, and the dumbbell-shaped subtype is the most challenging. OBJECTIVE: To evaluate the efficiency and safety of the endoscope-assisted retrosigmoid intradural suprameatal approach (EA-RISA) for dumbbell trigeminal schwannomas and to compare EA-RISA with classic RISA. METHODS: A retrospective study of all patients with trigeminal schwannomas was performed with a focus on dumbbell tumors. Tumors were classified according to a modified Samii classification. Extent of tumor removal, outcome, and morbidity rates in the 2 subgroups were compared. RESULTS: Twenty patients were enrolled: 8 had dumbbell-shaped tumors (type C1), 8 had middle fossa tumors (A1-3), 3 had extracranial extension (D2), and 1 had posterior fossa tumor. Gross total resection was achieved in 15 and near-total resection in 5 patients. In 4 patients with dumbbell tumors, the classic RISA (Samii approach) was used; EA-RISA was used in the other 4 patients. The extent of petrous apex drilling was determined individually on the basis of the anatomic variability of suprameatal tubercle and degree of tumor-induced petrous apex erosion; in 2 patients, only minimal drilling was needed. The endoscope was applied after microsurgical tumor removal and in 3 of 4 patients revealed a significant unrecognized tumor remnant in the anterolateral and superolateral aspects of the Meckel cave. Thus, the EA-RISA technique allowed gross total resection of the tumor. CONCLUSION: The EA-RISA enlarges the exposure obtained with the classic RISA. Its judicious use can help achieve safe and radical removal of dumbbell-shaped trigeminal schwannomas (C1 type).
BACKGROUND: Trigeminal schwannomas are the most common intracranial nonvestibular schwannomas, and the dumbbell-shaped subtype is the most challenging. OBJECTIVE: To evaluate the efficiency and safety of the endoscope-assisted retrosigmoid intradural suprameatal approach (EA-RISA) for dumbbell trigeminal schwannomas and to compare EA-RISA with classic RISA. METHODS: A retrospective study of all patients with trigeminal schwannomas was performed with a focus on dumbbell tumors. Tumors were classified according to a modified Samii classification. Extent of tumor removal, outcome, and morbidity rates in the 2 subgroups were compared. RESULTS: Twenty patients were enrolled: 8 had dumbbell-shaped tumors (type C1), 8 had middle fossa tumors (A1-3), 3 had extracranial extension (D2), and 1 had posterior fossa tumor. Gross total resection was achieved in 15 and near-total resection in 5 patients. In 4 patients with dumbbell tumors, the classic RISA (Samii approach) was used; EA-RISA was used in the other 4 patients. The extent of petrous apex drilling was determined individually on the basis of the anatomic variability of suprameatal tubercle and degree of tumor-induced petrous apex erosion; in 2 patients, only minimal drilling was needed. The endoscope was applied after microsurgical tumor removal and in 3 of 4 patients revealed a significant unrecognized tumor remnant in the anterolateral and superolateral aspects of the Meckel cave. Thus, the EA-RISA technique allowed gross total resection of the tumor. CONCLUSION: The EA-RISA enlarges the exposure obtained with the classic RISA. Its judicious use can help achieve safe and radical removal of dumbbell-shaped trigeminal schwannomas (C1 type).
Authors: Xiao Wu; Shen Hao Xie; Bin Tang; Le Yang; Li Min Xiao; Han Ding; You Yuan Bao; Zhi Gao Tong; Tao Hong Journal: Neurosurg Rev Date: 2020-02-19 Impact factor: 3.042
Authors: Maick Willen Fernandes Neves; Paulo Henrique Pires de Aguiar; Telmo Augusto Barba Belsuzarri; André Monteiro Soares de Araujo; Samantha Lorena Paganelli; Marcos Vinicius Calfat Maldaun Journal: J Neurol Surg B Skull Base Date: 2018-08-28