Analysis of the Effect of Facial Nerve Processing in the Surgery of Paraganglioma of the Lateral Skull Base Area

  Objective  To summarize the key points of the operation related to the facial nerve function after surgery of paraganglioma involving the jugular foramen in the lateral skull base.

  Methods  We retrospectively analyzed the clinical data of patients with lateral skull base paraganglioma involving jugular foramen that were diagnosed and treated in Peking Union Medical College Hospital from August 2015 to January 2021. According to the relationship between the tumor and the facial nerve, the facial nerve was treated in different ways during the operation. The postoperative facial nerve function of patients with different treatments is summarized.

  Results  A total of 30 patients with lateral skull base paraganglioma in the jugular foramen area were included. The Fisch classification of these patients was as followed: C1(n=3), C2(n=6), C2De1(n=2), C2Di1(n=2), C3De1(n=7), C3Di1(n=5), C3Di2(n=3), C4De1(n=1), C4Di1(n=1). Preoperative facial nerve function assessed by House-Brackmann (HB) grade: grade Ⅰ-Ⅱ (n=22), grade Ⅲ (n=2), grade Ⅳ (n=3), grade Ⅴ(n=2), grade Ⅵ(n=1). All tumors were completely resected, which was verified by post-operational MRI. No recurrence was observed during the medium follow-up of 886 days. All of the postoperative nerve function refers to the results of the last follow-up. Anterior facial nerve rerouting was performed in 15 cases whose tumor did not invade the facial nerve. The postoperative facial nerve function was HB grade Ⅰ-Ⅱ in 13 cases and HB grade Ⅲ in 2 cases. The tumors were adhesive to the facial nerve in 2 cases. The tumors and the facial nerve were successfully separated in both cases; one achieved HB grade Ⅰ-Ⅱ, while the other was HB grade Ⅰ-Ⅱ postoperatively. In 13 cases, the tumor wrapped the facial nerve. Among those patients, the tumor was separated from the facial nerve in 1 case, with the postoperative facial nerve function of HB grade Ⅲ. In the remaining 12 cases, the facial nerve was resected together with the tumor. Facial nerve reconstruction was performed in 3 cases in the same or the second surgery. The postoperative facial nerve function was HB gradeⅠ-Ⅱ in 1 case and HB grade Ⅲ in the other 2 cases. The postoperative facial nerve function in the remaining 9 cases that did not receive facial nerve reconstruction was HB grade Ⅵ.

  Conclusions  In patients with lateral skull base paraganglioma, anterior facial nerve rerouting has a slight effect on the function of facial nerve, if the tumor does not invade the facial nerve. It is difficult to separate the tumor and the facial nerve, if the facial nerve is wrapped by the tumor, and the rate of postoperative facial nerve paralysis is higher in these cases.