Preconditioning with Foam-mediated External Suction on Flap Microvasculature and Perfusion in a Rodent Model

Abstract

Background: Foam-mediated external suction (FMES) has previously shown to improve tissue microcirculation. We hypothesized that preconditioning fasciocutaneous perforator flaps with FMES would augment perfusion and demonstrate greater capillary recruitment. Methods: Gluteal perforator flaps were designed on sixteen 400 g rats. Continuous FMES at −125 mm Hg was applied on one side (intervention) to precondition tissue for 5 days, with the contralateral side as a paired control. In group A, we assessed changes following pretreatment, after surgery, and 7 days postprocedure, and in group B, we evaluated changes during preconditioning alone. In group A (N = 8), control and intervention flaps were assessed using laser-assisted indocyanine green fluorescence angiography. In group B, flap regions were assessed using 4-dimensional computed tomographic angiography. All flaps were analyzed for microvessel density using micro–computed tomography and histological assessment using hematoxylin and eosin and CD3 immunohistochemistry. Results: Thirty-two flaps were included in this study (N = 16 intervention and matched controls). Four-dimensional computed tomographic angiography demonstrated 17% greater tissue perfusion in preconditioned flaps (mean, 78.7 HU; SD, 8.8) versus controls (mean, 67.3 HU; SD, 15.7; P < 0.01). Laser-assisted indocyanine green fluorescence angiography showed a 30% higher mean absolute intensity in preconditioned flaps versus controls (P < 0.01). Postsurgery mean absolute intensity in preconditioned flaps remained 21% higher than in controls (P = 0.03). Preconditioned flaps demonstrated a 2-fold increase in mean vessel volume of 9.1 mm3 (SD, 7) versus 4.5 mm3 (SD, 3) in controls (P = 0.04); there was a 33% higher mean area fraction of CD31 in preconditioned flaps, 3.9% (SD, 3) versus 2.9% (SD, 3) in controls (P = 0.03). Conclusion: FMES preconditioning has the potential to augment vascularity of tissue for flap harvest; however, further experimental studies are required to optimize strategies and evaluate long-term effects for clinical applications.

Early Experience with External Negative Pressure Delay in Free Anterolateral Thigh Perforator Flap Reconstruction

“…They found a 2-fold increase in mean vessel volume and a 30% increase in absolute intensity when evaluated with indocyanine green angiography in preconditioned flaps. 14 Other authors have reported similar findings of increased vascularity and improved flap survival in animal models when treated with external negative pressure. [15][16][17][18][19] It is unclear what the optimal treatment conditions and duration of therapy are at the present time.…”

“…The most common pressure setting reported is −125 mm Hg, and both continuous and intermittent suction settings have been utilized. 12–16 The report time period of treatment also varies, with the most common length of treatment being 5–7 days before intervention. 12–16 We present our initial experience using ENPD in free ALT flap reconstruction of upper extremity defects.…”

“…External negative pressure delay has the potential to provide results similar to those of traditional surgical delay, while being cost effective, safer, and more convenient for patients. Case RepoRt been [12][13][14][15][16] The report time period of treatment also varies, with the most common length of treatment being 5-7 days before intervention. [12][13][14][15][16] We present our initial experience using ENPD in free ALT flap reconstruction of upper extremity defects.…”

“…Case RepoRt been [12][13][14][15][16] The report time period of treatment also varies, with the most common length of treatment being 5-7 days before intervention. [12][13][14][15][16] We present our initial experience using ENPD in free ALT flap reconstruction of upper extremity defects.…”