Trans-tonsillar approach for resection of a tumor located in the lateral aspect of the medulla: 3D surgical video

The porpose of this video is to describe the microsurgical corridor of the trans-tonsillar approach for resection of a tumor located in the right lateral aspect of the medulla.We presented a 56-year-old patient with headache and diplopia. On the preoperative MRI we found a localized tumor with surrounding edema, in the anterior portion of the right cerebellomedullary fissure and on the PET-CT a hyper-metabolic lesion in the right lung. We decided to excise the intracranial lesion given the risk of a post-radiotherapy edema. We performed a suboccipital approach extended to the right side. On the intradural stage, the lesion wasn was not reachable through a sub-tonsillar access because it was in front of the right tonsil. For this reason the surgical team decided to modify the initial plan, so a trans-tonsillar corridor was chosen. Pathological anatomy reveals metastasis of a lung adenocarcinoma. The patient evolved favorably, without neurologic deficit, and the postoperative MRI showed adequate resection and disappearance of the edema. The patient gave his written consent for the use of photos, images and surgical video in this work.In the neurosurgical literature there are some descriptions of the sub-occipital sub-tonsillar approach, among which we find cadaveric studies [1], technical notes [2] and reports of their application in various pathologies [3–5]. However, the use of the trans-tonsillar pathway is not described in neurosurgical bibliopraphy. This fact attracts attention, since resection or coagulation of only cerebellar tonsils does not generate a clinically significant neurological deficit. This suggests that the trans-tonsillar pathway, if necessary, is a valid option.The current work constitutes the first report of the usage of a suboccipital trans-tonsillar approach.