title: Influence of two types of self-retaining retractors on multifidus muscle blood flow during dorsolateral thoracolumbar hemilaminectomy in dogs.
abstract: OBJECTIVE
  To assess the influence of the use of Gelpi and Grevel retractors on multifidus muscle blood flow during hemilaminectomy, using a dorsolateral approach, for acute disc extrusion in dogs as measured by laser speckle contrast imaging (LSCI).
  
  
  METHODS
  Blood flow in the multifidus muscles was measured intra-operatively using LSCI prior to insertion of the retractors, immediately after hemilaminectomy and removal of the retractors, and after 10 minutes of lavage of the surgical site. Plasma creatine kinase levels were measured preoperatively and 12-24 hours postoperatively.
  
  
  RESULTS
  Muscular blood flow was significantly decreased following retraction and remained lower than initial values 10 minutes after lavage in all dogs. The decrease in blood flow was significantly greater with Gelpi retractors (n = 8) than with Grevel retractors (n = 10). No significant relation was found between the duration of retraction and postoperative changes in creatine kinase levels or blood flow.
  
  
  CONCLUSIONS
  Findings in this study demonstrate a drop in blood flow within the multifidus muscles using the dorsolateral approach regardless of retractor type used. Gelpi retractors seem to have greater influence on muscular blood flow than Grevel retractors. Further studies are warranted to confirm this second finding.
authors.forename: D
authors.initials: D
authors.lastname: Rohner
authors.forename: S
authors.initials: S
authors.lastname: Forterre
authors.forename: H
authors.initials: H
authors.lastname: Rohrbach
authors.forename: A
authors.initials: A
authors.lastname: Bürki
authors.forename: D
authors.initials: D
authors.lastname: Gorgas
authors.forename: J
authors.initials: J
authors.lastname: Howard
authors.affiliation: Prof. Dr. Franck Forterre, DVM, Diplomate ECVS, Universität Bern, Vetsuisse Faculty, Department of Clinical Veterinary Medicine, Laenggassstrasse 128, 3012 Bern, Switzerland, Phone: +41 31 631 23 15, Fax: +41 31 631 22 75, E-mail: franck.forterre@vetsuisse.unibe.ch.
authors.forename: F
authors.initials: F
authors.lastname: Forterre
mesh_terms: D000818:Animals; D003402:Creatine Kinase / Q000097:blood; D004283:Dog Diseases / Q000601:surgery*; D004285:Dogs / Q000601:surgery; D005260:Female; D007432:Intraoperative Period; D007796:Laminectomy / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D008159:Lumbar Vertebrae / Q000601:surgery; D008297:Male; D064170:Paraspinal Muscles / Q000098:blood supply* / Q000601:surgery; D012039:Regional Blood Flow; D013525:Surgical Instruments / Q000662:veterinary*; D013904:Thoracic Vertebrae / Q000601:surgery
chemical_list: D003402:Creatine Kinase
keywords: Self-retaining retractors; blood flow; dog; multifidus muscle; thoracolumbar disc extrusion