Vascular Cast to Program Antistenotic Hemodynamics and Remodeling of Vein Graft.

The structural stability of medical devices is established by managing stress distribution in response to organ movement. Veins abruptly dilate upon arterial grafting due to the mismatched tissue property, resulting in flow disturbances and consequently stenosis. Vascular cast is designed to wrap the vein-artery grafts, thereby adjusting the diameter and property mismatches by relying on the elastic fixity. Here, a small bridge connection in the cast structure serves as an essential element to prevent stress concentrations due to the improved elastic fixity. Consequently, the vein dilation is efficiently suppressed, healthy (laminar and helical) flow is induced effectively, and the heathy functions of vein grafting are promoted, as indicated by the flow directional alignment of endothelial cells with arterialization, muscle expansion, and improved contractility. Finally, collaborative effects of the bridge drastically suppress stenosis with patency improvement. As a key technical point, the advantages of the bridge addition are validated via the computational modeling of fluid-structure interaction, followed by a customized ex vivo set-up and analyses. The calculated effects are verified using a series of cell, rat, and canine models towards translation. The bridge acted like "Little Dutch boy" who saved the big mass using one finger by supporting the cast function.

Sequential reconstruction for recurrent head and neck cancer: A 10-year experience.

BACKGROUND: Most patients with head and neck cancer successfully undergo oncologic resection followed by free or local flap reconstruction, depending on the tumor's size and location. Despite effective curative resection and reconstruction, head and neck cancer patients still face a high risk of recurrence and the possibility of a second primary cancer. Moreover, surgeons hesitate to perform sequential reconstruction following curative resection for several reasons. Few large-scale studies on this subject are available. Therefore, we retrospectively evaluated the outcome of sequential head and neck reconstruction to determine the possible risks. METHODS: In total, 467 patients underwent head and neck reconstruction following cancer resection at our center from 2008 to 2017. Of these cases, we retrospectively reviewed the demographic and clinical features of 58 who had sequential head and neck reconstruction following resection of recurrent cancer. RESULTS: Our study included 43 males (74.1%) and 15 females (25.9%). The mean age at the initial operation was 55.4±15.3 years, while the mean age at the most recent operation was 59.0±14.3 years. The interval between the first and second operations was 49.2±62.4 months. Twelve patients (20.7%) underwent surgery on the tongue, and 12 (20.7%) had procedures on the oropharynx. Thirty-four patients (58.6%) received a sequential free flap reconstruction, and 24 patients (41.4%) were treated using locoregional flaps. No cases of flap failure occurred. CONCLUSIONS: Our findings suggest that patients who need additional operations with recurrent head and neck cancer could optimally benefit from sequential curative resections and reconstructions.

Analysis of factors involved in brain-death donor processing for face transplantation in Korea: How much time is available from brain death to transplantation?

BACKGROUND: Face transplantation has naturally evolved from reconstructive procedures. However, few institutions perform face transplantations, because it is time-consuming and it is necessary to justify non-vital organ transplantation. We investigated the process of organ donation from brain-dead patients and the possibility of incorporating face transplantation into the donation process. METHODS: A retrospective review was performed of 1,074 brain-dead patients from January 2015 to December 2016 in Korea. We analyzed the time intervals from admission to brain death decisions (first, second, and final), the causes of brain death, and the state of the transplanted organs. RESULTS: The patient base (n=1,074) was composed of 747 males and 327 females. The average period between admission to the first brain death decision was 8.5 days (±15.3). The average time intervals between the first brain death decision and medical confirmation using electroencephalography and between the first brain death decision and the final determination of brain death were 16 hours 58 minutes (±14 hours 50 minutes) and 22 hours 57 minutes (±16 hours 16 minutes), respectively. The most common cause of brain death was cerebral hemorrhage/stroke (42.3%), followed by hypoxia (30.1%), and head trauma (25.2%). CONCLUSIONS: When face transplantation is performed, the transplantation team has 22 hours 57 minutes on average to prepare after the first brain death decision. The cause of brain death was head trauma in approximately one-fourth of cases. Although head trauma does not always imply facial trauma, surgeons should be aware that the facial tissue may be compromised in such cases.

Extended temporalis flap for skull base reconstruction.

Traditionally, a galeal flap has been used for skull base reconstruction. In addition to the galeal flap, several other flaps, such as the temporalis muscle flap or the free vascularized flap, can be options for skull base reconstruction, and each option has advantages and disadvantages. Certain cases, however, can be challengeable in the application of these flaps. We successfully managed to cover a skull base defect using an extended temporalis flap. Herein, we present the case and introduce this novel method.

Evaluation of the Relationship Between Flap Tension and Tissue Perfusion in Implant-Based Breast Reconstruction Using Laser-Assisted Indocyanine Green Angiography.

BACKGROUND: For implant-based breast reconstruction, inadequate tissue perfusion may cause devastating complications. Tissue tension by inadequate implant volume may reduce tissue perfusion by stretching and collapsing the capillaries. The SPY system is used to perform intraoperative fluorescence angiography with indocyanine green to assess visually the blood flow and evaluate tissue perfusion. However, there is no report yet about how mastectomy flap perfusion changes with the expander-filling volume. Therefore, to analyse the changes of tissue perfusion of the mastectomy flap according to the tension level, we used the SPY system and adjusted the filling volume of the tissue expander to change the tension on the skin flap. METHODS: Ten breasts of ten patients who underwent immediate two-stage, implant-based breast reconstructions were included. The expander-filling volume just before mastectomy flap blanching was set as 100%. Based on this, the expander-filling volume was reduced to 50% and increased to 150%. Ingress and egress rates were evaluated using the SPY system at each condition and analysed by a linear mixed model using least square means. RESULTS: The mean ingression rates were 138, 100, and 65%, and the mean egression rates were 145, 100, and 66% at 50, 100, and 150% inflation, respectively. CONCLUSIONS: It was objectively proven that tissue perfusion deteriorates as the tension applied on the flap increases. On the basis of this finding, we can control the amount of inflation volume of the expander or remove the skin in the pre-ischaemic condition to reduce complications of implant-based breast reconstruction.

The use of acellular dermal matrix in immediate two-stage prosthetic breast reconstruction provides protection from postmastectomy radiation therapy: a clinicopathologic perspective.

Although there is ample evidence showing that radiation therapy increases the risk of complications of breast reconstruction, the efficacy of human acellular dermal matrix (CGCryoDerm®) in immediate tissue expander breast reconstruction in the setting of postmastectomy radiation therapy has not been fully elucidated. In this study, we report our institutional experience with pertinent refined surgical technique, and determine whether acellular dermal matrices have a protective effect in this increasingly prevalent clinical setting. Twenty-six patients who underwent immediate two-stage breast reconstruction in the setting of postmastectomy radiation therapy with at least 2 years of follow-up were retrieved. Fifteen patents were reconstructed with ADM, whereas 11 patients were reconstructed without ADM. The occurrence of complications was assessed according to the reconstruction type (with ADM vs without ADM). Furthermore, in patients reconstructed with ADM (n = 15), immunohistochemistry was performed to analyze the breast capsule with ADM compared with that without ADM in the same patient, according to the expression of alpha-smooth muscle actin (α-SMA). The occurrence of complications was significantly associated with the reconstruction type (with ADM vs. without ADM, p = 0.015). On the basis of the results of α-SMA staining, α-SMA+ myofibroblasts were relatively highly expressed throughout the breast capsule without ADM. On the contrary, α-SMA+ myofibroblasts present at the breast capsule adjacent to the ADM were scarce and irregularly scattered. Use of an acellular dermal matrix may be recommended to patients who are concerned about complications after immediate two-stage breast reconstruction in the setting of postmastectomy radiation therapy.