Thermal damage assessment of novel bipolar forceps in a sheep model of spinal surgery.

Abstract

Heat transfer from bipolar tips to adjacent tissue presents a risk of thermal injury during spine surgery. The present study was designed to determine wither bipolar forceps using a novel heat pipe thermal regulation technology resulted in decreased collateral thermal injury of adjacent tissue compared with traditional bipolar forceps (control). Eight sheep underwent multilevel laminectomy and controlled bipolar coagulation of the dorsal spinal dura mater at multiple levels using forceps with or without heat pipe technology (24 spinal segments tested; heat pipe, n=11; non-heat pipe, n=11; sham, n=2). The severity (range, 1-5) and size of thermal injury to the spinal cord resulting from forceps with vs without heat pipe were assessed via histological analysis at 8 days postoperatively. Macroscopic occlusion of the pial vein underlying the segment of epidural coagulation occurred at surgery in 64% of segments (7 of 11) coagulated with control forceps but did not occur in any segments coagulated with heat pipe forceps (P<.005). The mean width (0.58+/-0.58 vs 1.4+/-0.77 mm; P<.05) and cross-sectional area of unintended thermal injury (1.2+/-1.7 vs 4.9+/-3.2 mm2; P<.05) were decreased in segments treated with heat pipe forceps compared with control. The severity of thermal injury was decreased in segments coagulated with (median, grade 1) vs without (median, grade 3) heat pipe forceps (P<.05). Bipolar forceps that incorporate heat pipe technology limited thermal spread and reduced the extent of unintended injury to the spinal cord and collateral vessels.