Schönfeld Annemarie, Kabra Zacharia Mbäıdjol, Constantinescu Mihai, Bosshardt Dieter, Stoffel Michael H, Peters Kirsten, Frenz Martin
Department of Biomedical Photonics, University of Bern, Institute of Applied Physics, Sidlerstrasse 5, Bern 3012, Switzerland.
Department of Cell Biology, University Medicine Rostock, Schillingallee 69, Rostock 18057, Germany.
Lasers Surg Med. 2017 Dec;49(10):928-939. doi: 10.1002/lsm.22701. Epub 2017 Jul 12.
The clinical application of laser-assisted vascular anastomosis is afflicted by unreliable and low bonding strengths as well as tedious handling during microvascular surgery. The challenge to be met arises from the flow-off of the chromophore during soldering that changes the absorption and stains the surrounding tissue, leading to an uncontrollable thermal damage zone. In this study, we investigated the feasibility to produce an indocyanine green (ICG)-loaded patch by electrospinning and tested its applicability to both in vitro and in vivo microvascular laser soldering.
A blend of polycaprolactone and ICG was electrospun to produce a pliable patch. Prior to soldering, the patch was soaked in 40% wt. bovine serum albumin solution. The solder patch was wrapped in vitro around blood vessel stumps of rabbit aortas. An intraluminal balloon catheter enabled an easy alignment and held the setup in place. The soldering energy was delivered via a diffusor fiber from the vessel lumen using a diode laser at 810 nm. During the procedure, the surface temperature was observed with an infrared camera. Afterward, samples were embedded in methylmethacrylate and epon to study thermal damage. The quality of the fusion was assessed by measuring the tensile strength. After in vitro tests with rabbit aortas, eight large white pigs were subjected to an acute in vivo experiment, and the artery of the latissimus dorsi flap was anastomosed to the distal femoral artery.
The ICG-loaded patch, produced by electrospinning, has a thickness of 279 ± 62 μm, a fiber diameter of 1.20 ± 0.19 μm, and an attenuation coefficient of 1,119 ± 183 cm at a wavelength of 790 nm. The patch was pliable and easy to handle during surgery. No leakage of the chromophore was observed. Thermal damage was restricted to the Tunica adventitia and Tunica media and the area of the vessel wall that was covered with the patch. Six pigs were successfully treated, without any bleeding and with a continuous blood flow. The in vivo flap model yielded a similar tensile strength compared to in vitro laser-assisted vascular anastomoses (138 ± 52 vs. 117 ± 30 mN/mm ).
Our study demonstrated the applicability of the ICG-loaded patch for laser-assisted vascular anastomosis. By using electrospinning, ICG could be bound to polymer fibers, avoiding its flow-off and the staining of the surrounding tissue. This patch demonstrated several advantages over liquid solder as it was easier to apply, ensured a high and reliable bonding strength while maintaining a constant concentration of ICG concentration during the surgery. Lasers Surg. Med. 49:928-939, 2017. © 2017 Wiley Periodicals, Inc.
激光辅助血管吻合术在临床应用中存在结合强度不可靠且较低以及在微血管手术中操作繁琐的问题。面临的挑战源于焊接过程中发色团的流失，这会改变吸收情况并使周围组织染色，导致不可控的热损伤区域。在本研究中，我们研究了通过静电纺丝制备负载吲哚菁绿（ICG）的贴片的可行性，并测试了其在体外和体内微血管激光焊接中的适用性。
将聚己内酯和ICG的混合物进行静电纺丝以制备柔韧的贴片。在焊接前，将贴片浸泡在40%重量的牛血清白蛋白溶液中。将焊接贴片在体外包裹在兔主动脉的血管残端周围。腔内球囊导管便于对齐并将装置固定到位。使用810 nm的二极管激光器通过扩散光纤从血管腔内传递焊接能量。在手术过程中，用红外相机观察表面温度。之后，将样品包埋在甲基丙烯酸甲酯和环氧树脂中以研究热损伤。通过测量拉伸强度评估融合质量。在用兔主动脉进行体外测试后，对八只大型白色猪进行急性体内实验，将背阔肌皮瓣的动脉与股动脉远端进行吻合。
通过静电纺丝制备的负载ICG的贴片厚度为279±62μm，纤维直径为1.20±0.19μm，在790 nm波长下的衰减系数为1119±183 cm⁻¹。该贴片柔韧且在手术中易于操作。未观察到发色团泄漏。热损伤局限于外膜和中膜以及贴片覆盖的血管壁区域。六只猪成功接受治疗，无任何出血且血流持续。体内皮瓣模型的拉伸强度与体外激光辅助血管吻合术相似（138±52对117±30 mN/mm²）。
我们的研究证明了负载ICG的贴片在激光辅助血管吻合术中的适用性。通过使用静电纺丝，ICG可与聚合物纤维结合，避免其流失和周围组织染色。与液体焊料相比，该贴片具有几个优点，因为它更易于应用，在手术过程中保持ICG浓度恒定的同时确保了高且可靠的结合强度。《激光外科与医学》49:928 - 939，2017。©2017威利期刊公司。
