1 3 Int J Clin Oncol DOI 10.1007/s10147-017-1148-4 ORIGINAL ARTICLE The rate of facial nerve dysfunction and time to recovery after intraparotid and extraparotid facial nerve exposure and protection in head and neck cutaneous tumor surgery Yasuhiro Nakamura 1 · Yukiko Teramoto 1 · Yuri Asami 1 · Taichi Imamura 1 · Sayuri Sato 1 · Ryota Tanaka 2 · Hiroshi Maruyama 2 · Yoshiyuki Nakamura 2 · Yasuhiro Fujisawa 2 · Manabu Fujimoto 2 · Akifumi Yamamoto 1 Received: 21 February 2017 / Accepted: 31 May 2017 © Japan Society of Clinical Oncology 2017 intraparotid rates of paresis were 48% (11/23 branches) and 21.1% (4/19 branches), respectively, P = 0.139; and the average recovery periods were 10.3 and 9.3 weeks, respec- tively, P = 0.64. Conclusions The functional outcome, regardless of the different sites of facial nerve exposure, was almost always either complete facial nerve sparing or transient dysfunc- tion that resolved within 6 months. Keywords Skin cancer · Melanoma · Squamous cell carcinoma · Facial nerve · Sentinel lymph node biopsy · Neck dissection Introduction The head and neck account for only 9% of the total body surface area, but 80% of all skin cancers occur in these regions [1], most likely because of their greater exposure to the sun. Despite the increasing incidence of head and neck skin cancer, the prognosis is generally excellent. How- ever, patients who present with advanced disease, includ- ing large and/or rapidly growing lesions, recurrent lesions, and regional metastases, have also increased in number. These patients risk invasion by the tumor into deep struc- tures including the facial nerve [1]. Tumor involvement or intraoperative injury to the facial nerve causes cosmetic and functional morbidity, including brow ptosis, corneal exposure, sagging of the lower lip, and inability to show the lower teeth on the affected side. Fortunately, the incidence of facial nerve dysfunction at first presentation is rare. A preoperatively intact facial nerve can often be dissected away from the tumor with exposure and intra-operative protection of the nerve. However, facial nerve paresis (weakness) or paralysis is possible after such Abstract Background Most patients with head and neck skin tumors present with normal facial nerve function. A common treat- ment strategy for these patients is facial nerve preservation surgery, although the degree to which the nerve is success- fully preserved is still unclear. Data on the incidence and recovery of facial nerve dysfunction are woefully lacking in the field of dermato-oncology. Methods In 23 patients with normal preoperative facial nerve function, we retrospectively reviewed twenty-six head and neck surgical interventions that included facial nerve exposure and protection, focusing particularly on the differences in outcome between intraparotid and extrapa- rotid exposure of the facial nerve branches. Results Eleven of the 26 cases (42.4%) developed transient paresis, but only one (3.8%) developed permanent pare- sis. Of 41 dissected facial nerve branches, 14 developed transient paresis (34.1%) and one, a marginal mandibular branch, developed permanent paresis (2.4%). The branches most susceptible to developing paresis were the temporal (4/6 branches, 66.7%) and marginal mandibular branches (8/17 branches, 47.1%). Although the rate of paresis was higher, and ensuing recovery period slightly longer in the extraparotid dissection group compared to the intraparotid dissection group, there were no statistically significant differences between the two groups. The extraparotid and * Yasuhiro Nakamura ynakamur@saitama-med.ac.jp 1 Department of Skin Oncology/Dermatology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan 2 Department of Dermatology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan