Lateral Suboccipital Approach in Semisitting Position for Resection of Vagal Schwannoma: 2-Dimensional Operative Video

We present a case of a sizeable vagal schwannoma that was resected through a lateral suboccipital approach in semisitting position. An extra-axial lesion, occupying the left cerebellomedullary cistern and extending from the pontomedullary junction to the jugular foramen was incidentally discovered in a 40-year-old woman afflicted with secondary progressive multiple sclerosis during repeated magnetic resonance imaging (Fig. 1). On physical examination, a mild deviation of the uvula to the right and a diminished gag reflex were observed. The patient was referred to our department after considerable growth of the lesion was noted and a broad interdisciplinary consensus was reached to treat the lesion surgically.A gross total resection was achieved, histopathology confirmed a WHO I schwannoma with a low proliferation index. Postoperative dysphonia resolved completely within a few weeks, there was no collateral neurological deficit and especially no functional dysphagia. At 3-year follow-up, there was no indication of residual or recurrence.This 2-dimensional video demonstrates pre- and postoperative imaging, positioning and set-up of operating room, anatomical and surgical nuances of the skull base approach, and the operative technique for microdissection of the schwannoma from the critical neurovascular structures (Fig. 2).In summary, the lateral suboccipital approach in semisitting position is a powerful tool in the armamentarium for the microsurgical management of various pathologies residing in the posterior cranial fossa, especially large and vascularized schwannomas. Provided the necessary anesthesiological precautions and intraoperative procedures the semisitting position is safe and effective.The link to the video can be found at: https://youtu.be/-9o_qJGkQhg.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Retrosigmoid Approach

Introduction Neurosurgical anatomy is traditionally taught via anatomic and operative atlases; however, these resources present the skull base using views that emphasize three-dimensional (3D) relationships rather than operative perspectives, and are frequently written above a typical resident's understanding. Our objective is to describe, step-by-step, a retrosigmoid approach dissection, in a way that is educationally valuable for trainees at numerous levels. Methods Six sides of three formalin-fixed latex-injected specimens were dissected under microscopic magnification. A retrosigmoid was performed by each of three neurosurgery residents, under supervision by the senior authors (C.L.W.D. and M.J.L.) and a graduated skull base fellow, neurosurgeon, and neuroanatomist (M.P.C.). Dissections were supplemented with representative case applications. Results The retrosigmoid craniotomy (aka lateral suboccipital approach) affords excellent access to cranial nerve (CN) IV to XII, with corresponding applicability to numerous posterior fossa operations. Key steps include positioning and skin incision, scalp and muscle flaps, burr hole and parasigmoid trough, craniotomy flap elevation, initial durotomy and deep cistern access, completion durotomy, and final exposure. Conclusion The retrosigmoid craniotomy is a workhorse skull base exposure, particularly for lesions located predominantly in the cerebellopontine angle. Operatively oriented neuroanatomy dissections provide trainees with a critical foundation for learning this fundamental skull base technique. We outline a comprehensive approach for neurosurgery residents to develop their familiarity with the retrosigmoid craniotomy in the cadaver laboratory in a way that simultaneously informs rapid learning in the operating room, and an understanding of its potential for wide clinical application to skull base diseases.

Three-Dimensional Computed Tomography Angiography Assisted Resection of Ventral Foramen Magnum and Jugular Foramen Tumours via Modified Far Lateral Suboccipital Approach

Objective: The anatomical relationship of ventral foramen magnum and jugular foramen tumour is complex and the operation is very difficult. The aim of this study was to summarize the microsurgical experience of the removal of the ventral foramen magnum and jugular foramen tumours via the modified far lateral suboccipital approach assisted by three-dimensional computed tomography angiography (3D-CTA). Methods: The clinical data and follow-up results of 13 cases of 3D-CTA assisted suboccipital far lateral approach from July 2011 to September 2017 were analyzed retrospectively. There were 5 males and 8 females. Preoperative CT and MRI were used for routine imaging diagnosis, and the 3D-CTA simulated surgical approach was performed. The preoperative operation scheme was established, and the risk of operation was evaluated according simulated operation. After individualized exposure, the modified far lateral suboccipital approach was completed under the neuroelectrophysiological monitoring technique. Results: The preoperative images were completely consistent with the findings in the surgery. There were 9 cases of jugular foramen tumour and 4 cases of ventral foramen magnum tumour. Of the 13 cases, only 1 case of jugular glomus tumour had extra-cranial residual, while the whole intracranial tumour was removed. In other 12 cases, the tumours were completely removed under the microscope. After operation, the headache disappeared, and hearing loss was improved. There was no perioperative deaths, infection and cerebrospinal fluid leakage. The facial paralysis was occurred in 1 patient. After 3–39 months of follow-up, there was no recurrence of tumour, or new nerve function defect. Hoarseness, choking of drinking water and numbness of limbs were all improved at the end of the follow-up period. The symptoms of postoperative facial paralysis were also improved during the follow-up period. Conclusion: After the preoperative simulation and evaluation by 3D-CTA, the ventral foramen magnum and jugular foramen tumours can be rescted safely and effectively via far modified lateral suboccipital approach.