Effects of Preconditioning With Transcutaneous Electrical Nerve Stimulation Monitored by Infrared Thermography on the Survival of Pedicled Perforator Flaps in a Rat Model.

Abstract

Pedicled perforator partial or complete necrosis with a rate of 13.7%. This study was undertaken to test whether preconditioning with transcutaneous electrical nerve stimulation (TENS) monitored by infrared thermography protect against partial necrosis by converting the choke anastomoses to the true anastomoses via inducing heme oxygenase-1 (HO-1) in a rat pedicled perforator flap model. Seventy-two Sprague-Dawley rats were randomly assigned to the control, the TENS, the TENS + SnPP (tin protoporphyrin; HO-1 activity inhibitor; 50 μmol/kg) and the TENS +0.9% saline groups. On the unilateral dorsum of the rats, a rectangular flap donor site of 11 × 3 cm was marked out, which contained three perforator angiosomes and two choke zones. On days 1, 3 and 4, 1 hour of TENS (biphasic pulses, 25 mA, 80 Hz, 200 μs) was applied to the flap donor sites, respectively. On day 5, after the flap donor sites were assessed by infrared thermography, the flaps were harvested based on the deep circumflex iliac artery perforator. Infrared thermography showed that the choke zones in the flap donor sites presented white in the TENS and the TENS +0.9% saline groups, whereas they presented red in the control and the TENS + SnPP groups. Postmortem arteriography showed that the number of arterioles across each choke zone significantly increased in the TENS and the TENS +0.9% saline groups compared with the control and the TENS + SnPP groups. Immunohistochemistry and western blot showed a significant increase in HO-1 in the choke zones after TENS preconditioning. The necrotic area percentage of the flaps was significantly decreased in the TENS (4.3% ± 2.6%) and the TENS +0.9% saline groups (4.5% ± 2.3%) compared with the control (24.8% ± 5.0%) ( P < 0.001); there was no significant difference between the TENS and the TENS + SnPP (24.4% ± 7.3%) groups. These data show that TENS preconditioning monitored by infrared thermography might be a promising strategy to prevent pedicled perforator flaps from partial necrosis.