Proof-of-Concept Studies for Marker-Based Ultrasound Doppler Analysis of Microvascular Anastomoses in a Modified Large Animal Model

Abstract

Background Despite attempts to solve the problem of flap monitoring, assessing the patency of vascular anastomoses postoperatively remains challenging. In addition, experimental data suggest that near-total vessel occlusion is necessary to produce significant changes in clinical appearance or monitoring devices. We sought to develop an ultrasound-based system that would provide definitive data on anastomotic function.

Methods A system was developed consisting of a resorbable marker made from poly-lactic-co-glycolic acid (PLGA) implanted during the time of surgery coupled with ultrasound software to detect the anastomotic site and perform Doppler flow analysis. Surgical procedures consisting of microvascular free tissue transfer or femoral vessel cutdown were performed followed by marker placement, closure, and ultrasound monitoring. Transient vascular occlusion was produced via vessel-loop constriction. Permanent thrombosis was induced via an Arduino-controlled system applying current to the vessel intima.

Results Four surgeries (one femoral vessel cutdown and three microvascular tissue transfer) were successfully performed in Yorkshire swine. The markers were readily visualized under ultrasound and provided a bounding area for Doppler analysis as well as orientation guidance. Transient spasm and partial occlusion were detected based on changes in Doppler data, while complete occlusion was evident as the total loss of color Doppler.

Conclusion In this preliminary report, we have conceptualized and developed a novel system that enables the real-time visualization of vascular pedicle flow at the bedside using Doppler ultrasound and a surgically implanted marker. In a large animal model, use of the system allowed identification of the anastomosis, flow analysis, and real-time detection of flow loss.

Keywords

free flap - microvascular reconstruction - flap monitoring - ultrasound - Doppler

• References

• 1 Mirzabeigi MN, Wang T, Kovach SJ, Taylor JA, Serletti JM, Wu LC. Free flap take-back following postoperative microvascular compromise: predicting salvage versus failure. Plast Reconstr Surg 2012; 130 (3) 579-589
• 2 Smit JM, Zeebregts CJ, Acosta R, Werker PM. Advancements in free flap monitoring in the last decade: a critical review. Plast Reconstr Surg 2010; 125 (1) 177-185
• 3 Jacobs P, Kowatsch R. Sterrad Sterilization System: a new technology for instrument sterilization. Endosc Surg Allied Technol 1993; 1 (1) 57-58
• 4 Leto Barone AA, Leonard DA, Torabi R , et al. The gracilis myocutaneous free flap in swine: an advantageous preclinical model for vascularized composite allograft transplantation research. Microsurgery 2013; 33 (1) 51-55
• 5 Hennan JK, Huang J, Barrett TD , et al. Effects of selective cyclooxygenase-2 inhibition on vascular responses and thrombosis in canine coronary arteries. Circulation 2001; 104 (7) 820-825
• 6 Dogné JM, Rolin S, Pétein M , et al. Characterization of an original model of myocardial infarction provoked by coronary artery thrombosis induced by ferric chloride in pig. Thromb Res 2005; 116 (5) 431-442
• 7 Chen KT, Mardini S, Chuang DC , et al. Timing of presentation of the first signs of vascular compromise dictates the salvage outcome of free flap transfers. Plast Reconstr Surg 2007; 120 (1) 187-195
• 8 Nakatsuka T, Harii K, Asato H , et al. Analytic review of 2372 free flap transfers for head and neck reconstruction following cancer resection. J Reconstr Microsurg 2003; 19 (6) 363-368, discussion 369
• 9 Lohman RF, Langevin CJ, Bozkurt M, Kundu N, Djohan R. A prospective analysis of free flap monitoring techniques: physical examination, external Doppler, implantable Doppler, and tissue oximetry. J Reconstr Microsurg 2013; 29 (1) 51-56
• 10 Lohman RF, Ozturk CN, Djohan R, Tang HR, Chen H, Bechtel KL. Predicting skin flap viability using a new intraoperative tissue oximetry sensor: a feasibility study in pigs. J Reconstr Microsurg 2014; 30 (6) 405-412
• 11 Haddock NT, Gobble RM, Levine JP. More consistent postoperative care and monitoring can reduce costs following microvascular free flap reconstruction. J Reconstr Microsurg 2010; 26 (7) 435-439
• 12 Pelletier A, Tseng C, Agarwal S, Park J, Song D. Cost analysis of near-infrared spectroscopy tissue oximetry for monitoring autologous free tissue breast reconstruction. J Reconstr Microsurg 2011; 27 (8) 487-494
• 13 Russell JA, Conforti ML, Connor NP, Hartig GK. Cutaneous tissue flap viability following partial venous obstruction. Plast Reconstr Surg 2006; 117 (7) 2259-2266 , discussion 2267–2268
• 14 Bedri MI, Chang BW. Use of the implantable Doppler in free tissue breast reconstruction. Clin Plast Surg 2011; 38 (2) 309-312
• 15 Smit JM, Klein S, de Jong EH, Zeebregts CJ, de Bock GH, Werker PM. Value of the implantable doppler system in free flap monitoring. J Plast Reconstr Aesthet Surg 2012; 65 (9) 1276-1277
• 16 Gimbel ML, Rollins MD, Fukaya E, Hopf HW. Monitoring partial and full venous outflow compromise in a rabbit skin flap model. Plast Reconstr Surg 2009; 124 (3) 796-803
• 17 Bellamy JL, Mundinger GS, Flores JM , et al. Do adjunctive flap-monitoring technologies impact clinical decision making? An analysis of microsurgeon preferences and behavior by body region. Plast Reconstr Surg 2015; 135 (3) 883-892
• 18 Kapoor DN, Bhatia A, Kaur R, Sharma R, Kaur G, Dhawan S. PLGA: a unique polymer for drug delivery. Ther Deliv 2015; 6 (1) 41-58
• 19 Wu XS, Wang N. Synthesis, characterization, biodegradation, and drug delivery application of biodegradable lactic/glycolic acid polymers. Part II: biodegradation. J Biomater Sci Polym Ed 2001; 12 (1) 21-34
• 20 Uhrich KE, Cannizzaro SM, Langer RS, Shakesheff KM. Polymeric systems for controlled drug release. Chem Rev 1999; 99 (11) 3181-3198
• 21 Nuutinen JP, Clerc C, Virta T, Törmälä P. Effect of gamma, ethylene oxide, electron beam, and plasma sterilization on the behaviour of SR-PLLA fibres in vitro. J Biomater Sci Polym Ed 2002; 13 (12) 1325-1336
• 22 Pozniak MA, Allan LP. Clinical Doppler Ultrasound. Churchill Livingstone, 2e, 2006. ISBN 978-0443101168