Laser-Doppler Measurements of Spinal Cord Blood Flow Changes During Hemilaminectomy in Chondrodystrophic Dogs with Disk Extrusion YASMINDA MALIK, DVM, DAVID SPRENG, DVM, Diplomate ECVS & ACVECC, MARTIN KONAR, DVM, Diplomate ECVDI, MARCUS G. DOHERR, DVM, PhD, Diplomate ECVPH, ANDRE JAGGY, PhD, Diplomate ECVN, JUDITH HOWARD, DVM, Diplomate ACVIM à , and FRANCK FORTERRE, DVM, Diplomate ECVS à Objectives—(1) To assess spinal cord blood flow (SCBF) during surgical treatment of disk extrusion in dogs and (2) to investigate associations between SCBF, clinical signs, presurgical MRI images, and 24-hour surgical outcome. Study Design—Cohort study. Animals—Chondrodystrophic dogs with thoracolumbar disk extrusion (n ¼ 12). Methods—Diagnosis was based on clinical signs and MRI findings, and confirmed at surgery. Regional SCBF was measured intraoperatively by laser-Doppler flowmetry before, immediately after surgical spinal cord decompression, and after 15 minutes of lavaging the lesion. Care was taken to ensure a standardized surgical procedure to minimize factors that could influence measurement readings. Results—A significant increase in intraoperative SCBF was found in all dogs (Wilcoxon’s signed- rank test; P ¼ .05) immediately after spinal cord decompression and after 15 minutes. Changes in SCBF were not associated with duration of clinical signs; initial or 24-hour neurologic status; or degree of spinal cord compression assessed by MRI. Conclusion—SCBF increases immediately after spinal cord decompression in dogs with disk her- niation; however, increased SCBF was not associated with a diminished 24-hour neurologic status. Clinical Relevance—An increase in SCBF does not appear to be either associated with the degree of spinal cord compression or of a magnitude sufficient to outweigh the benefit of surgical decom- pression by resulting in clinically relevant changes in 24-hour outcome. r Copyright 2009 by The American College of Veterinary Surgeons INTRODUCTION C HANGES IN spinal cord perfusion play a major role in spinal cord injury in disk herniation. For normal spinal cord microcirculatory flow and function, the cord arterial system must be perfused by pressures 430 mmHg at the distal end of the intercostal arteries. The blood supply to the spinal cord depends both on the perfusion pressure head and the number of anastomotic channels. When either factor is sufficiently disturbed, the cord circulation will be compromised. 1 Spinal cord blood flow (SCBF) decreases shortly after trauma. 2 The initial hypoxia that results from impact in- jury appears to be so critical that the resulting pathology is virtually identical to that following ischemia produced by occlusion of the spinal cord blood supply. 3 As SCBF is compromised, it is unable to accommodate alterations in arterial pressure, blood oxygen, and carbon dioxide Study carried out at the Small Animal Clinic, Department of Surgery, Radiology, and Neurology, University of Berne, Berne, Switzerland à Contributed equally. Address reprint requests to Dr. Franck Forterre, DVM, Diplomate ECVS, Department of Surgery, Small Animal Clinic, University of Berne, La¨ nggasse 128, CH-3012 Berne, Switzerland. E-mail: frank.forterre@kkh.unibe.ch. Submitted December 2007; Accepted July 2008 From the Department Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland. r Copyright 2009 by The American College of Veterinary Surgeons 0161-3499/09 doi:10.1111/j.1532-950X.2009.00529.x 457 Veterinary Surgery 38:457–462, 2009