title: The impact of minimizing brain retraction in aneurysm surgery: evaluation using magnetic resonance imaging.
abstract: BACKGROUND
  Recent advances in skull base and microsurgical techniques minimize the need for brain retraction.
  
  
  OBJECTIVE
  We studied the impact of such techniques in 36 patients (51 aneurysms) using magnetic resonance imaging (MRI).
  
  
  METHODS
  Preoperative and 24 hours postoperative MR imaging was performed in patients undergoing microsurgical clipping of intracranial aneurysms. Images were evaluated for parenchymal signal changes. During surgery, use and time of brain retraction were recorded. The degree of cortical injury was quantified using a 0 to 3 scale (grade 0 = normal surface; 1 = pial/arachnoidal damage; 2 = gray matter injury; 3 = contusion/necrosis).
  
  
  RESULTS
  Brain retraction by use of a brain spatula was used in all patients. Retraction times ranged from 14 to 290 minutes (mean, 84.1). Cortical surface changes were grade 0 in 86% and grade 1 in 14%; none showed grade 2 or 3 changes. In the postoperative MRI, 4 patients presented with parenchymal alterations, 4 with edema (11.1%), and 1 patient had additional contusion (2.8%). All lesions were confined to the temporal pole. The grade of cortical surface changes was not related to lesions found on MR imaging. No patients showed retraction-related neurological deficits.
  
  
  CONCLUSIONS
  The incidence of evident mechanical parenchymal injury (infarction or contusion) is very low when appropriate microsurgical and skull base techniques are used. Minor pia-arachnoid injury should nevertheless continue to be attended through future advances.
authors: Department of Neurosurgery, University Hospital Zürich, Zürich, Switzerland. nkrayenbuehl@bluewin.ch
authors: Niklaus
authors: N
authors: Krayenbühl
authors: Minna
authors: M
authors: Oinas
authors: Eren
authors: E
authors: Erdem
authors: Ali F
authors: AF
authors: Krisht
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000601:surgery*; D001930:Brain Injuries / Q000209:etiology; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008866:Microsurgery / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods*; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods*; D013525:Surgical Instruments