Surgery for Gliomas and Other Mass Lesions of the Brainstem

The lateral infratrigeminal transpontine window to deep pontine lesions

“…The following is a list of skull base approaches that have been described in the literature as effective means of removing brainstem lesions through different approaches: lateral perspective, retrosigmoid, retrolabyrinthine, translabyrinthine, transcochlear, anterior petrosectomy, far lateral transcondylar, subtemporal transtentorial, lateral supracerebellar infratentorial, and the anterior transpetrosal approach of Kawase. [3][4][5]9,13,14,17,18,20,25,30,37 The recent widespread use of endoscopic transnasal techniques also facilitates anterior transclival approaches to resect brainstem lesions, 19 but this approach does not appear suitable for deep lesions due to the ventral position of the corticospinal tract and the risk of vascular injury to the basilar artery and its branches. All of these approaches share the common aim of circumventing the need for a posterior brainstem incision.…”

“…4,15,20,31 There are many variables that affect the results of this surgery such as patient selection, surgical techniques, and available technologies. In addition, there is currently no consensus surrounding the decision-making process that guides the surgeon to choose this approach.…”

“…Despite this report, in the following years the relatively easy surgical accessibility of the floor of the fourth ventricle induced many authors to use and study this route to the deep pons, and relatively "safe" entry zones were identified. 4,20,34 More recently, the need to further reduce the impact of surgical sequelae affecting a patient's quality of life and the refinement of neurophysiological monitoring has pushed some groups to explore and develop lateral alternative approaches to the deep pons. 10,15,17,25 Given these historical considerations, this study focused attention on the technical aspects and results of surgery for deep pontine lesions when approached through the lateral infratrigeminal window.…”

Direct Approach to the Ventrolateral Medulla for Cavernous Malformation. Case Report.

“…The surgical approach depends on the location of the cavernous malformation in the brainstem, and the technical considerations for surgical intervention to treat intrinsic lesions of the ventral medulla. [1][2][3]11,20) Surgery has been considered risky due to the possibility of injuring vital structures or damaging the perforating arteries coursing from the ventrolateral aspect of the medulla. Safe entry zones might be identified, even on the anterior surface of the medulla, through an anterolateral sulcus at the level between the radicles of the hypoglossal nerve and the C-1.…”

“…5,7,[13][14][15][16]21) Neurological deficits are likely to worsen due to repeated hemorrhages, so the current trend is toward aggressive management of lesions reaching the pial or ependymal surface of the brainstem, but extreme care is required perioperatively since vital structures in life-support functions are located at the brainstem. 2,5,9,[11][12][13][14]16,21) Direct resection through various approaches has been used for cavernous malformations located primarily in the midbrain and pons since there is only minor risk of inflicting further neurological damage. 4,6,8,[10][11][12][17][18][19] The indications for surgical treatment and selection of the most appropriate surgical routes may be indeterminable for cavernous malformations with neither bulging nor extension into the pial or ependymal surface.…”