title: Selection of surgical approaches for small acoustic neurinomas.
abstract: BACKGROUND
  The purpose of this study was to evaluate the results of surgery for small acoustic neurinomas at our institute via the middle cranial fossa and retrosigmoid approaches, and to determine the indications for each approach.
  
  
  METHODS
  Fifty-three patients with unilateral tumors less than 2 cm in diameter were studied. Surgery was performed via the middle cranial fossa approach in 36 tumors and via the retrosigmoid approach in 17 tumors.
  
  
  RESULTS
  The hearing preservation rate was 68% (36/53) in all patients, 93% (14/15) in patients with intracanalicular tumors, 79% (15/19) in patients with tumors less than 1 cm in diameter, and 43% (7/19) in patients with tumors between 1 and 2 cm in diameter. The facial nerve function was excellent or good in 80% (42/53), 74% (11/15), 84% (16/19), and 78% (15/19), respectively. Among the 19 patients with tumors between 1 and 2 cm in diameter, the frequencies of hearing preservation and of excellent or good facial nerve function (47% and 87%, respectively) in the 15 patients approached via the retrosigmoid approach were higher than those (0% and 50%, respectively) in the four patients approached via the middle cranial fossa approach.
  
  
  CONCLUSIONS
  We conclude that tumors smaller than 2 cm should be removed because preservation of hearing as well as facial nerve function may be possible in almost all of these patients. Tumors larger than 1 cm should be surgically treated through the retrosigmoid approach.
authors.affiliation: Department of Neurological Surgery, Ehime University School of Medicine, Onsen-gun, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kumon
authors.forename: S
authors.initials: S
authors.lastname: Sakaki
authors.forename: K
authors.initials: K
authors.lastname: Kohno
authors.forename: S
authors.initials: S
authors.lastname: Ohta
authors.forename: K
authors.initials: K
authors.lastname: Nakagawa
authors.forename: S
authors.initials: S
authors.lastname: Ohue
authors.forename: S
authors.initials: S
authors.lastname: Murakami
authors.forename: N
authors.initials: N
authors.lastname: Yanagihara
mesh_terms: D000328:Adult; D000368:Aged; D003399:Craniotomy / Q000009:adverse effects / Q000379:methods* / Q000592:standards; D005154:Facial Nerve / Q000503:physiopathology; D005260:Female; D034381:Hearing Loss / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000150:complications / Q000473:pathology / Q000601:surgery*; D018579:Patient Selection; D016896:Treatment Outcome