title: Temporary facial nerve dysfunction after parotidectomy correlates with tumor location.
abstract: OBJECTIVE
  To investigate the clinical factors associated with temporary facial nerve dysfunction (TFND) following surgery for benign parotid gland tumors.
  
  
  METHODS
  We reviewed the records of 175 patients with benign parotid gland tumors who underwent partial parotidectomy at Yokohama City University Medical Center in Japan. TFND was found in 33 patients (18.9%). We used two hypothetical lines in magnetic resonance imaging (MRI) images to define the tumor location (upper/lower or anterior/posterior) in the parotid gland. We then studied the associations of TFND with the following clinical factors: patient age, tumor size, histopathological diagnosis, and the location of the tumor within the parotid gland (superficial lobe/deep lobe; upper part/lower part; and anterior part/posterior part).
  
  
  RESULTS
  Tumors located in the upper parts, anterior parts or the deep lobes of the parotid gland had statistically higher incidences of TFND compared with tumors located in the lower parts, posterior parts or the superficial lobe (P<0.001, <0.001, <0.01, respectively). The odds ratio for the risk of TFND was significantly high if tumors were located in the upper parts, the anterior parts or the deep lobes with stepwise multivariate regression analysis. The other factors, including patient's age, tumor size, histopathology of the tumor, and inadequate surgeon's experience, were not apparent risks for TFND.
  
  
  CONCLUSIONS
  Parotid gland tumors located in the upper parts, the anterior parts or the deep lobes had a higher risk of TFND. The two hypothetical lines we used were shown to be useful to define the tumor location, eventually the risk of TFND.
authors.affiliation: Department of Otolaryngology, Yokohama City University Medical Center, Urafune-cho 4-57, Minami-ku, Yokohama 232-0024, Japan. Electronic address: ikoma-r@minamikyousai.jp.
authors.forename: Ryo
authors.initials: R
authors.lastname: Ikoma
authors.affiliation: Department of Otolaryngology, Yokohama City University Medical Center, Urafune-cho 4-57, Minami-ku, Yokohama 232-0024, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Ishitoya
authors.affiliation: Department of Otolaryngology, Yokohama City University Medical Center, Urafune-cho 4-57, Minami-ku, Yokohama 232-0024, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sakuma
authors.affiliation: Department of Otolaryngology, Yokohama City University Medical Center, Urafune-cho 4-57, Minami-ku, Yokohama 232-0024, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Hirama
authors.affiliation: Department of Otolaryngology, Yokohama City University Medical Center, Urafune-cho 4-57, Minami-ku, Yokohama 232-0024, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Shiono
authors.affiliation: Department of Biology and Function in Head and Neck, Yokohama City University Graduate School of Medicine, Fukuura 3-9, Kanazawa-ku, Yokohama 236-0004, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Komatsu
authors.affiliation: Department of Biology and Function in Head and Neck, Yokohama City University Graduate School of Medicine, Fukuura 3-9, Kanazawa-ku, Yokohama 236-0004, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Oridate
mesh_terms: D000235:Adenolymphoma / Q000473:pathology / Q000601:surgery*; D000236:Adenoma / Q000473:pathology / Q000601:surgery; D008949:Adenoma, Pleomorphic / Q000473:pathology / Q000601:surgery*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005154:Facial Nerve / Q000033:anatomy & histology*; D005155:Facial Nerve Diseases / Q000209:etiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010306:Parotid Gland / Q000473:pathology*; D010307:Parotid Neoplasms / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D047368:Tumor Burden; D055815:Young Adult
keywords: Parotid gland tumor; Partial parotidectomy; Temporary facial nerve dysfunction; Tumor location