title: Retrosigmoid suprafloccular transhorizontal fissure approach for resection of brainstem cavernous malformation.
abstract: OBJECTIVE
  This study examined the usefulness of a surgical approach (retrosigmoid suprafloccular transhorizontal fissure approach) for resection of brainstem cavernous malformations (CMs).
  
  
  METHODS
  An anatomic study concerning the retrosigmoid suprafloccular transhorizontal fissure approach was performed with 3 cadaveric heads. Clinical course was retrospectively reviewed for 10 patients who underwent microsurgical resection of brainstem CMs with this approach. Medical, surgical, and neuroimaging records of these patients were evaluated.
  
  
  RESULTS
  In the anatomic study, after standard suboccipital retrosigmoid craniotomy, the horizontal fissure on the petrosal surface of the cerebellum was dissected between the superior semilunar lobule and flocculus. With this approach, the root entry zone of the trigeminal nerve and the middle cerebellar peduncle could be exposed by superior retraction of the superior semilunar lobule. The lateral surface of the pons was then easily visible around the root entry zone. When this approach was used for 10 brainstem CMs, complete resection was achieved in 9 patients (90%). No mortality was encountered in this study. New neurological deficits occurred in the early postoperative period for 4 patients but were transient in 3 patients. Neurological status at final follow-up was improved in 4 patients (40%), unchanged in 5 patients (50%), and worse in 1 patient (10%) compared with preoperative conditions.
  
  
  CONCLUSIONS
  The retrosigmoid suprafloccular transhorizontal fissure approach is useful for the resection of lateral pontine CMs.
authors.affiliation: Division of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA. ohue@m.ehime-u.ac.jp
authors.forename: Shiro
authors.initials: S
authors.lastname: Ohue
authors.forename: Takanori
authors.initials: T
authors.lastname: Fukushima
authors.forename: Allan H
authors.initials: AH
authors.lastname: Friedman
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kumon
authors.forename: Takanori
authors.initials: T
authors.lastname: Ohnishi
mesh_terms: D000328:Adult; D001933:Brain Stem / Q000098:blood supply / Q000473:pathology* / Q000601:surgery*; D002102:Cadaver; D002531:Cerebellum / Q000033:anatomy & histology / Q000601:surgery*; D003388:Cranial Fossa, Posterior / Q000033:anatomy & histology / Q000601:surgery; D003399:Craniotomy / Q000379:methods*; D004210:Dissection / Q000379:methods; D005260:Female; D020786:Hemangioma, Cavernous, Central Nervous System / Q000098:blood supply / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D012189:Retrospective Studies; D014656:Vascular Surgical Procedures / Q000379:methods; D055815:Young Adult