Reply: Effects of Negative-Pressure Wound Therapy on Primary Closed Defects after Superficial Circumflex Iliac Artery Perforator Flap Harvest: Randomized Controlled Study

Abstract

Sir: We thank the authors for their interest in our article.1 Recently, incisional negative-pressure wound therapy has been used to enhance healing for surgical incisions in patients with a high risk of wound dehiscence. As shown in this article, the application of negative-pressure wound therapy has many benefits. However, before applying negative-pressure wound therapy to patients, clinicians need to know the limited benefits and possible complications by understanding the physics and physiology of the therapy. The following are answers to your questions. First, it became a common belief that when using negative-pressure wound therapy dressing, tissue pressure increases proportional to the amount of negative pressure applied.2,3 The additional tissue pressure, with a pressure setting of −150 mmHg with continuous pressure mode, was +2 to 10 mmHg in noncircumferential wounds. This increased tissue pressure has a minimal effect on healthy tissues. However, in ischemic wounds and tissues with compromised perfusion, tissue perfusion might be jeopardized. There are many clinical reports of minimizing the tissue pressure increase by using a lower pressure setting.4–6 In these cases, lowering the pressure to −50 mmHg over the incisional wound can be an option. However, our series involves healthy donor sites and furthermore uses the cyclic mode to minimize the chance of possible tissue ischemia caused by the compression effect. This compression, in our hands, is enough to give the tie-over bolster fixation effect. This will minimize shearing of the skin and thus allow faster healing and reduce seroma/hematoma formation as shown in the article. Second, using the Jackson-Pratt drain is within good practice when closing a wound with dead space. By maintaining the negative pressure of the drain, hematoma collection will be minimized. One cannot compare the effect of the drain to the negative-pressure wound therapy applied on the skin because it is used for different purposes. The negative-pressure wound therapy over the skin will improve perfusion of the skin and play a role in fixation. If one were to see the fluid drain to the negative-pressure wound therapy system, it would mean that either the Jackson-Pratt drain was not functioning or secure closure of the skin was not performed. Third, the PeriScan PIM 3 System does not use a probe but rather uses a 785-nm, 70-mW laser (Perimed AB, Stockholm, Sweden) to calculate the blood perfusion of the closed margin. The measurement is performed immediately after the dressing is removed. DISCLOSURE Dr. Hong and Dr. Suh are consultants for Daewoong Pharmaceutical Company. No financial support was received regarding this study. Hyunsuk Peter Suh, M.D., Ph.D.Min Young Jang, R.N.Joon Pio (Jp) Hong, M.D., Ph.D., M.M.M.Seoul Asan Medical CenterUniversity of Ulsan College of MedicineSeoul, Republic of Korea