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

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. 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. 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.