Effect of Subcutaneous Adrenaline/Saline/Lidocaine Injection on Split-Thickness Skin Graft Donor Site Wound Healing

[Background] Subcutaneous injection of tumescent solution, which contains local anesthetic, adrenaline, and saline, before split-thickness skin graft harvesting, shows a significant hemostatic effect. This method can reduce the initial bleeding from the donor site. The aim of this study is to assess the benefits of controlling the bleeding from donor sites by tumescent injection. A randomized, controlled trial was performed to compare the wound healing of split-thickness skin graft donor sites treated with or without tumescent injection. [Methods] This randomized, controlled trial examined donor site healing days as the main measure of outcome. postoperative pain, donor site ulceration, and scar quality were evaluated as secondary outcome measures. Patients planned for split-thickness skin graft harvest were randomly assigned to receive either pre-harvest subcutaneous injection of local anesthetic, adrenaline, and saline solution (tumescent solution) (Group 1) or post-harvest application of adrenaline solution-soaked gauze to the skin graft donor sites (Group 2). Donor sites were treated with calcium alginate dressings after graft harvesting. On the 10th postoperative day, the dressings were removed and donor site healing were measured. Follow-up evaluation of scar quality was performed 6 months after surgery. Postoperative pain was evaluated on the 1st day after operating. [Results] Forty-five patients (26 males; average age 61.8 years) completed the late follow-up evaluation (6 months postoperatively), with 26 patients in group 1 and 19 in group 2. There were no significant differences between the two groups in any of the outcome measures. [Conclusion] Tumescent technique provides sufficient hemostasis in split skin graft donor sites, especially the initial bleeding just after graft harvesting, without any negative effects. Larger series should be studied to evaluate the effect in donor site wound healing

Free Flap Blood Flow Evaluated Using Two-Dimensional Laser Speckle Flowgraphy

Objective. We investigated the efficiency of laser speckle flowgraphy for evaluating blood flow in free flaps used for plastic surgery. Methods. We measured blood flow using a visual laser meter capable of providing two-dimensional color graphic representations of flow distribution for a given area using a dynamic laser speckle effect. Using laser speckle flowgraphy, we examined the blood flow of 20 free flaps applied following the excision of head and neck tumors. Results. After anastomosis of the feeding and draining blood vessels and sewing the flap, musculocutaneous (MC) flaps showed significantly lower blood flow than jejunal or omental flaps (P < .05). The ratio of blood flow decrease from the edge to the center was significantly greater in MC flaps than in jejunal or omental flaps (P < .001). Conclusion. Laser speckle flowgraphy is useful for the perioperative measurement of blood flow in free flaps used in plastic surgery. This method is a highly useful, practical, and reliable tool for assessing cutaneous blood flow and is expected to be applicable to several clinical fields

Hemodynamic Analysis of a Microanastomosis Using Computational Fluid Dynamics

[Background] Technical issues in free flap transfer, such as the selection of recipient vessels and the positioning and method of anastomosis of the vascular pedicle, have been the subject of vigorous debate. Recent developments in computational fluid dynamics (CFD) have enabled the analysis of blood flow within microvessels. In this study, CFD was used to analyze hemodynamics in a microanastomosis. [Methods] In the fluid calculation process, the fluid domain modelizes microvessels with anastomosis. The inlet flow conditions were measured as venous waveform, and the fluid is simulated as blood. Streamlines (SL), wall shear stress (WSS), and oscillatory shear index (OSI) at the anastomosis were visualized and analyzed for observing effects from the flow field. [Results] Some flow disruption was evident as the SL passed over the sutures. The maximum recorded WSS was 13.37 Pa where the peak of a suture was exposed in the lumen. The local maximum value of the OSI was 0.182, recorded at the base of the anastomosis on the outflow side. [Conclusion] In the ideal anastomosis, the SL is disrupted as little as possible by the sutures. The WSS indicated that thrombus formation is unlikely to occur at suture peaks, but more likely to occur at the base of sutures, where the OSI is high. Tight suture knots are important in microanastomosis

Risk Factors of Free Flap Complications in Reconstruction for Head and Neck Cancer

Background: Although head and neck reconstruction using free flaps has become a common procedure, flap complications remain a concern. This study aimed to analyze the risk factors of free flap complications and to identify the causes of these complications. Methods: We studied 97 patients with head and neck cancer with intraoral defects who underwent reconstruction using free flaps at Tottori University Hospital between 2011 and 2020. We used a retrospective cohort study design to investigate whether flap complications, including flap necrosis (total and partial) and flap dehiscence, were related to various factors, including the underlying disease condition, treatment status, and surgical factors. Results: Of the 97 patients analyzed, total flap necrosis was observed in one patient (1.0%). The incidence rate of flap complications, including flap necrosis and flap dehiscence, was 29.9%. When the time taken to perform one vascular anastomosis, including preparation of the recipient vessel and flap vessel, exceeded 30 min, the incidence rates of flap necrosis (total and partial) (odds ratio, 8.30; 95% confidence interval, 1.91-36.00; P = 0.005) and flap dehiscence (odds ratio, 3.46; 95% confidence interval, 1.05-11.36; P = 0.041) increased significantly. Conclusion: The time taken to perform one vessel anastomosis was the factor that contributed the most to the incidence of flap complications. Reconstructive surgeons should reduce the incidence of flap complications by keeping the known risk factors of the surgery in mind and by aiming to complete a vascular anastomosis time, including the time taken for the preparation of vessels, of ≤ 30 min per vessel during surgery

Analysis of the Optimum Tapering Angle in Microanastomosis Using Computational Fluid Dynamics

Background: In free flap transfer, size discrepancy between the vascular pedicle and recipient vessel can create a problem for microsurgeons and sometimes induces postoperative thrombus formation. When there is a major difference between the diameters of the vascular pedicle and the recipient vessel, the larger vessel is often tapered to perform the anastomosis properly. However, the decision on the tapering angle used depends mostly on the operator’s experience. In this study, computational fluid dynamics (CFD) was used to investigate the optimum tapering angle. Methods: Using ANSYS ICEM 16.0 (ANSYS Japan, Tokyo, Japan), simulated vessels of diameters 1.5 mm and 3.0 mm were designed and then used to produce four anastomosis models with the 3.0-mm vessel tapered at angles of 15º, 30º, 60º, and 90º (no tapering). Venous perfusion with a mean value of 13.0 mL/min was simulated, and this was passed through the four anastomosis models in both the forward direction (F), from the smaller to the larger vessel, and the retrograde direction (R), from the larger to the smaller vessel. The velocity, wall shear stress (WSS), and oscillatory shear index (OSI) were measured in these eight patterns and then analyzed using OpenFOAM version 5. Results: The decrease in velocity was limiting. The WSS was greater in the R direction than the F direction at every tapering angle. The OSI also tended to be almost the same in the F direction, and lower at smaller tapering angles in the R direction. And, it was greater in the F direction than in the R direction at every tapering angle. The OSI values for 15º and 30º were almost identical in the R direction. Conclusion: The risk of thrombus formation is thought to be lower when tapering is used for anastomosis if the direction of flow is from the larger to the smaller vessel, rather than vice versa. These results also suggest that the optimum tapering angle is approximately 30º in both directions

Considering the Better Donor-side in Reconstruction of Composite Radius After Resection of Spindle Cell Sarcoma Using Free Fibular Osteocutaneous Flap: A Case Report

Reconstruction of bone and soft-tissue defects in the forearm is a surgery that often proves unsuccessful. Free fibular osteocutaneous flaps are a useful material for reconstruction that enable simultaneous reconstruction of bone, skin, and soft tissues. However, in free fibular osteocutaneous flaps, the fibula, skin, and vascular pedicle are tightly bound together by the posterior intermuscular septum and the perforators that pass through the septum, giving the disadvantage of a low degree of freedom when setting these structures in place. We take into account the 3-dimensional structure of the free skin flap when selecting which lower leg to use as the donor. We report here the case of a 61-yearold man with defects in the radius, skin, and soft tissues after resection of spindle cell carcinoma of the right forearm, which was reconstructed using a free fibular osteocutaneous flap harvested from the left lower leg. Two years postoperatively, recovery has been uneventful with no complications. Donor-side selection of free fibular osteocutaneous flap is an important factor for safely completing composite radius reconstruction

Study on the neovascularization of limb ischemia induced by pretreatment with fucoidan

【Background】Peripheral artery disease（ PAD） caused the poor prognosis of the patients. The life style intervention is necessary to protect patients from PAD. Fucoidan is the member of the polysaccharide originated from Mozuku sea weed, which is useful supplement for life style related disease. 【Purpose】We examined whether fucoidan could improve limb ischemic lesions in mice and rats. 【Method and Result】We created the ischemic limb model of mice and rats and evaluated their blood flow using the laser Doppler blood perfusion. We separated them into three groups, control group （without any treatment），post-treatment group （treated with fucoidan after ischemia for 4 weeks），and pre- and post-treatment group （treated with fucoidan before ischemia for 1 week and after ischemia for 4 weeks）．Fucoidan significantly improved the blood perfusion of ischemic limb in pre- and post-treatment group compared to those in control group. Neovascularization was remarkably increased in muscle of ischemic limb in pre- and post-treatment group compared to those in control group. Fucoidan did not improve either the blood perfusion or neovascularization in post-treatment group. 【Conclusion】Pretreatment with fucoidan through oral administration would be a promising supplement for protection from PAD