Pons herniation after skull base chondrosarcoma surgery: A rare complication after transclival endoscopic endonasal approach.

Background: Intracranial chondrosarcomas are malignant tumors that most commonly affect the clivus region. For tumors in this location, the extended endoscopic endonasal approach could offer an alternative route. We present a case of pons herniation after this technique.

Case description: A 55-year-old female presented with a 6-month history of difficulty walking. The neurological evaluation showed asymmetric tetra paresis and involvement of the IX cranial nerve on the right side. Imaging exams showed a lesion at the upper clivus, with a possible diagnosis of chondrosarcoma. An extended transclival approach with partial resection and a multilayer closure were performed. The patient had a slight immediate improvement in muscle strength, and she was discharged home 5 days after surgery. Four weeks later, she evolved with worsening strength on the left side. A new image examination revealed an atypical protrusion of the pontine tissue through the bone defect at the opening of the clivus; a surgical revision was proposed, but the patient chose conservative management.

Conclusion: Pontine herniation is a rare complication with no defined cause. The use of a rigid material for closure could reduce the chances of this complication, but futher studies are necessary to reinforce that hypothesis.