Abstract
Objectives The main objective of this article is to describe a simple and safe protocol for
the microsurgical management of ventrally located intrinsic pontomedullary lesions
based on the retrosigmoid approach, cortectomy performed utilizing safe entry zones
of the pons and medulla, and a delicate microsurgical resection. The intraoperative
protocol includes redundant procedures that provide security in decision-making during
surgery.
Design A prospective series of 11 cases is presented. All patients were studied following
the same clinical and imaging workup. A regular retrosigmoid craniotomy surgical approach
was utilized. The peritrigeminal area in the pons and the olivary area in the medulla
were considered as the safe entry zones. Neuronavigation of the white fiber tracts
and electrophysiological monitoring were used as intraoperative aids to locate the
lesions, the safe entry zones, and the placement of the cortectomy.
Results Six lesions were pontine, two medullary, and the remaining six pontomedullary. Eight
lesions were cavernomas, while the remaining three tumors. Overall, we obtained a
postoperative functional improvement in the affected cranial nerves in 90.1% of the
patients and a total or partial recovery of long ascending or descending pathway symptoms
in 72.3% of the patients. All the patients were satisfied with the procedure and the
results.
Conclusions Radical resection of ventral intrinsic pontomedullary lesions displays a high degree
of intraoperative reliability, and a good clinical result is possible using simple
surgical procedures. The anatomical references are the first element in the decision-making
process during surgery.
Keywords
intrinsic pontomedullary cavernoma - intrinsic pontomedullary ventral lesion - retrosigmoid
approach - safe entry zones
