Primary nerve grafting: A study of revascularization.

It was the purpose of this study to evaluate the revascularization of primary nerve repair and grafts using orthogonal polarization spectral (OPS) (Cytometrix, Inc.) imaging, a novel method for real-time evaluation of microcirculatory blood flow. Twenty male Sprague Dawley rats (250 g) were anesthetized with vaporized halothane and surgically prepared for common peroneal nerve resection. Group I animals (n = 10) underwent primary neurorraphy following transection, utilizing a microsurgical technique with 10-0 nylon suture. Group II (n = 10) animals had a 7-mm segment of nerve excised, reversed, and subsequently replaced as a nerve graft under similar techniques. All animals were evaluated using the OPS imaging system on three portions (proximal, transection site/graft, and distal) of the nerve following repair or grafting. Reevaluation of 5 animals randomly selected from each group using the OPS imaging system was again performed on days 14 and 28 following microsurgical repair/grafting. Values were determined by percent change in vascularity of the common peroneal nerve at 0 hr following surgery. Real-time evaluation of blood flow was utilized as an additional objective criterion. Percent vascularity in group I and II animals increased from baseline in all segments at day 14. By day 28, vascularity in nerves of group I rats decreased in all segments to values below baseline, with the exception of the transection site, which remained at a higher value than obtained directly after surgical repair. In group II animals, vascularity remained above baseline in all segments except the distal segment, which returned to vascularity levels similar to those at 0 hr. Further, occlusion of the vessels demonstrated in the graft and distal segments following initial transection appeared to be corrected. This study suggests that revascularization may occur via bidirectional inosculation with favored proximal vascular growth advancement. The use of real-time imaging offers a unique evaluation of tissues through emerging technologies.

Laser flap delay: comparison of Erbium:YAG and CO2 lasers.

The delay phenomenon has long been recognized as a powerful tool in reconstructive surgery. This phenomenon involves creating alterations in skin flap blood supply or microcirculation to increase the size of the surviving flap. In the past many reconstructive surgeons depended on surgical delay as an integral part of their surgical planning. Today surgical delay remains a reliable method for maximizing flap survival. Although surgical delay remains the gold standard many have searched for methods to create the same effect with less morbidity and reduced cost. The purpose of this study was to determine whether near-scarless delay can be performed with either the Erbium:YAG or CO2 laser using a standard McFarlane skin flap model. Four groups were identified. Surgical delay, Erbium laser delay, and CO2 laser delay groups were each compared with a nondelayed control. Each group consisted of ten Sprague-Dawley rats. On Day 0 all delay procedures were performed on the lateral periphery of the outlined dorsal skin flaps. Interruption of this lateral blood supply was accomplished by two parallel 10-cm incisions in the surgical delay group. Likewise blood supply and microcirculatory alterations were accomplished in the laser delay groups by two parallel 10-cm laser treatments. On Day 7 a 10 x 4-cm cranially based dorsal skin flap was elevated. On Day 14 flap survival was analyzed by calculating percentage flap survival. The Erbium:YAG laser delay of the McFarlane flaps resulted in an average of 32 per cent less flap loss compared with controls (P = 0.0001). The CO2 laser resulted in an average of 36 per cent less flap loss compared with controls (P = 0.0002), whereas the surgical delay group had a 23 per cent smaller flap loss (P = 0.009). There was no significant difference between any of the delay groups. These results indicated that CO2 and Erbium:YAG lasers are as effective as surgery for delay of skin flaps in the rat model. They may provide an effective and inexpensive method for near-scarless skin flap delay in humans.