Chemical Delay: An Alternative to Surgical Delay Experimental Study

Abstract

The delay phenomenon has long been recognized as a powerful adjunct to flap surgery. Currently, delay procedures remain a reliable method of maximizing flap survival. Although delay yields successful results, the necessity of an additional surgical procedure is a persistent disadvantage from both clinical and economic perspectives. The authors' purpose is to demonstrate the usefulness of a novel chemical delay technique that obviates the need for a surgical delay procedure. This technique contains an epinephrine-loaded microsphere delivery system. In this study, 30 rats were subdivided into three groups of 10 animals. In group I, transverse rectus abdominis musculocutaneous (TRAM) flaps were delayed surgically 1 week before formal elevation. Group II (sham chemical delay) animals were injected with saline-loaded microspheres into the entire undersurface of the proposed TRAM flaps, which were elevated 1 week later. In group III rats, epinephrine-loaded microspheres were injected into the undersurface of the TRAM flaps to initiate a chemical delay 1 week before surgical elevation. Groups were compared via TRAM flaps 1 week after elevation. There was a significant difference between groups I and III in favor of surface area viability and angiographic assessment (p < 0.05). Surgical delay has traditionally been accepted to be the most reliable method of enhancing flap viability. Statistically similar results were obtained by chemical delay initiated by epinephrine-loaded microspheres. Chemical delay is less invasive, less time-consuming, and far more cost-effective compared with its surgical alternative. The chemical delay model lends further support to the role of relative hypoxia as the primary promoter of the delay phenomenon.

Basic Fibroblast Growth Factor Expression following Surgical Delay of Rat Transverse Rectus Abdominis Myocutaneous Flaps

“…16 -19 The delay of TRAM flaps can be performed many different ways, including complete division of skin and ipsilateral or bilateral dominant pedicle ligation or division. With the advent of minimally invasive surgery, there has been the development of endoscopic, 20 percutaneous embolization, 21 and even chemical 22 techniques. Despite continued interest in the delay phenomenon, the mechanism by which this occurs remains poorly understood.…”

Use of Systemic Rosmarinus Officinalis to Enhance the Survival of Random-Pattern Skin Flaps

“…Several systemic and local agents have been used to improve skin flap survival, but none that can prevent flap necrosis has been identified (1)(2)(3)(4).…”

Effect of long‐term application of epinephrine on rat skin vasculature: Experimental study

“…18 Although it is clinically used extensively, there is no information concerning the effects on soft tissues from its long-term administration. 19 Except for 5-¯uoroura-cil-epinephrine (5 FU-epinephrine)-loaded sustainedrelease gel implants and a single ceramic drug delivery system, there is no information available regarding the sustained release of msps containing epinephrine. 20,21 Mimicking its common role in local anesthetic formulations, in those studies epinephrine was only an accessory agent used to prolong the release of the active agent, 5-FU.…”

“…A well-de®ned technique was followed for harvesting the skin paddle. 15 Serum samples were separated, and epinephrine concentration in the serum was measured by using highperformance liquid chromotography (HPLC) (Waters, USA). 13 …”