title: Changes in Bypass Flow during Temporary Occlusion of Unused Branch of Superficial Temporal Artery.
abstract: OBJECTIVE
  Some neurosurgeons intentionally ligate the branches of the superficial temporal artery (STA) that are not used in standard STA-to-middle cerebral artery (MCA) anastomosis for the purpose of improving the flow rate in the bypass graft. We investigated changes in bypass flow during temporary occlusion of such unused branches of the STA.
  
  
  METHODS
  Bypass blood flow was measured by a quantitative microvascular ultrasonic flow probe before and after temporary occlusion of branches of the STA that were not used for anastomosis. We performed measurements on twelve subjects and statistically assessed changes in flow. We also examined all the patients with digital subtraction angiography in order to observe any post-operative changes in STA diameter.
  
  
  RESULTS
  Initial STA flow ranged from 15 mL/min to 85 mL/min, and the flow did not change significantly during occlusion as compared with pre-occlusion flow. The occlusion time was extended by 30 minutes in all cases, but this did not contribute to any significant flow change.
  
  
  CONCLUSIONS
  The amount of bypass flow in the STA seems to be influenced not by donor vessel status but by recipient vessel demand. Ligation of the unused STA branch after completion of anastomosis does not contribute to improvement in bypass flow immediately after surgery, and furthermore, carries some risk of skin necrosis. It is better to leave the unused branch of the STA intact for use in secondary operation and to prevent donor vessel occlusion.
authors.affiliation: Department of Neurosurgery, Bucheon St. Mary's Hospital, The Catholic University of Korea Collegs of Medicine, Bucheon, Korea.
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Kwang Wook
authors.initials: KW
authors.lastname: Jo
authors.forename: Young Woo
authors.initials: YW
authors.lastname: Kim
authors.forename: Seong Rim
authors.initials: SR
authors.lastname: Kim
authors.forename: Ik Seong
authors.initials: IS
authors.lastname: Park
authors.forename: Min Woo
authors.initials: MW
authors.lastname: Baik