title: Cavernous malformations of the brainstem: three-dimensional-constructive interference in steady-state magnetic resonance imaging for improvement of surgical approach and clinical results.
abstract: OBJECTIVE
  The indications for resection of cavernous malformations (CMs) of the brainstem include neurological deficits, (recurrent) hemorrhage, and surgically accessible location. In particular, knowledge of the thickness of the parenchymal layer and of the CM's spatial relation to nuclei, tracts, cranial nerves, and vessels is critical for planning the surgical approach. We reviewed the operative treatment of 13 patients with 14 brainstem CMs, with special regard to refined three-dimensional (3D)-constructive interference in steady-state (CISS) magnetic resonance imaging (MRI).
  
  
  METHODS
  Patients were evaluated neurologically and by conventional spin-echo/fast spin-echo and 3D-CISS MRI. Surgery was performed with the use of microsurgical techniques and neurophysiological monitoring.
  
  
  RESULTS
  Eleven CMs were located in the pons/pontomedullary region; 10 of the 11 were operated on via the lateral suboccipital approach. Three CMs were located near the floor of the fourth ventricle and operated on via the median suboccipital approach, with total removal of all CMs. Results were excellent or good in 10 patients; one patient transiently required tracheostomy, and two patients developed new hemipareses/ataxia with subsequent improvement. Not only did 3D-CISS sequences allow improved judgment of the thickness of the parenchymal layer over the lesion compared with spin-echo/fast spin-echo MRI, but 3D-CISS imaging also proved particularly superior in demonstrating the spatial relation of the lesion to fairly "safe" entry zones (e.g., between the trigeminal nerve and the VIIth and VIIIth nerve groups) by displaying the cranial nerves and vessels within the cerebellopontine cistern more precisely.
  
  
  CONCLUSIONS
  Surgical treatment of brainstem CMs is recommended in symptomatic patients. Especially in patients with lesions situated ventrolaterally, the 3D-CISS sequence seems to be a valuable method for identifying the CM's relation to safe entry zones, thereby facilitating the surgical approach.
authors.affiliation: Department of Neurosurgery, Ludwig-Maximilians-Universität, Klinikum Grosshadern, Munich, Germany. Stefan.Zausinger@med.uni-muenchen.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Zausinger
authors.forename: Indra
authors.initials: I
authors.lastname: Yousry
authors.forename: Hartmut
authors.initials: H
authors.lastname: Brueckmann
authors.forename: Robert
authors.initials: R
authors.lastname: Schmid-Elsaesser
authors.forename: Joerg-Christian
authors.initials: JC
authors.lastname: Tonn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001933:Brain Stem / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000601:surgery; D002426:Cavernous Sinus / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000601:surgery; D020785:Central Nervous System Vascular Malformations / Q000000981:diagnostic imaging* / Q000601:surgery; D002648:Child; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D011859:Radiography; D012189:Retrospective Studies