[Clinical study on endoscopic surgery for soft tissue necrosis of cranial base after radiotherapy for nasopharyngeal carcinoma].

To investigate the diagnosis and surgical treatment of patients with soft tissue necrosis of cranial base after radiotherapy for nasopharyngeal carcinoma (NPC). The clinical data of 7 NPC patients with soft tissue necrosis but not bone necrosis after radiotherapy were retrospectively analyzed.They were treated in Xiangya Hospital from 2015 to 2019. The clinical manifestations, diagnosis, treatment and prognosis were analyzed. The major clinical symptoms of the 7 patients were headache in 7 cases, hearing loss in 7 cases, long-term nasal malodor in 5 cases and epistaxis in 2 cases. All patients underwent high-resolution CT, MR and magnetic resonance angiography (MRA) before operation. All cases were treated with extended transnasal endoscopic approach under general anesthesia for resection of necrotic tissue. Five cases had their affected cartilaginous segments of the eustachian tubes partially or completely resected, 7 cases were treated with myringotomy and tube insertion, and 1 case was treated with pansinusectomy. Anti-inflammatory treatment were carried out during the perioperative period. The recovery of patients was observed and recorded through regular follow-up (from 6 months to 3 years) after the operation. Nasopharynx soft tissue lesions can be seen in seven patients with bone cortex integrity by CT, and small bubble shadow can be seen at junction area between skull base soft tissue lesions and skull base bone surface.MR and MRA examination showed extensive inflammatory changes of nasopharynx. Parapharyngeal irregular necrotic cavity was found in 6 cases without central enhancement, demonstrating edema of surrounding soft tissue. The necrotic tissue of all 7 patients was surgically removed. Postoperative pathological examinations confirmed that all of them were necrotic soft and cartilaginous tissue, without tumor recurrence. The symptoms of all patients were significantly alleviated after operation. Headache was cured in 5 cases and relieved in 2 cases. Nasal malodor was cured in 4 cases and alleviated in 1 case. During the follow-up period, 5 patients survived, and 2 patients who had their eustachian tube reserved died. One of them died of nasopharyngeal hemorrhage caused by recurrent nasopharyngeal necrosis 3 months after the operation. Another case died of severe intracranial infection 6 months after operation. The diagnosis of skull base soft tissue necrosis after radiotherapy for nasopharyngeal carcinoma needs comprehensive analysis of radiotherapy history, clinical manifestations and imaging examination. High resolution CT, MR and MRA of skull base are very important for diagnosis. Early active removal of large-scale necrotic lesions under endoscope and partial or total resection of eustachian tube cartilage according to the involvement of eustachian tube cartilage is effective means of controling skull base soft tissue necrosis after radiotherapy. The effective means of necrosis can improve the quality of life of patients.