Availability Of Recipient Vessels Research Articles

Extracorporeal Perfusion of Vascularized Composite Tissues: The Bridging Role of an Emerging Technology in Reconstructive Microsurgery.

Complex defects with exposed critical structures after trauma or tumor resections are routinely reconstructed with free flaps. In the current practice of reconstructive microsurgery, the success rate at high-volume centers is above 95%. However, despite high success rates, free tissue transfer is not without challenges and limitations. The high degree of technical skill and resources needed to perform these lengthy procedures are not fulfilled at every institution globally. In some cases, the availability of recipient vessels can be limited due to vascular disease or prior treatments. Additionally, perioperative patient decompensation could affect outcomes, especially in complex multitrauma patients. Therefore, an improved approach is still needed to ensure reliable flap transfer even in the presence of unanticipated events and compromised recipient vasculature. Considering the major advancements over the past few decades, further improvement at this point requires a paradigm shifting approach. Machine perfusion, classically used in the preservation of solid organs, offers a wide variety of implications for vascularized composite tissues. An extracorporeal perfusion system (EPS), similar to that used during cardiopulmonary bypass, can be used to isolate the tissue via cannulation of the primary artery and vein and provide temporary support. The research on this topic1 can be furthered to enable clinical use of such technology in three distinct purposes (Fig. 1).Fig. 1.: Conceptual schematic of the potential clinical needs that an extracorporeal perfusion system could address. Machine perfusion support could serve three distinct purposes in reconstructive microsurgery: (1) bridge-to-anastomosis, (2) bridge-to-neovascularization for traditional flaps, and (3) bridge-to-neovascularization for bioengineered flaps. Even the uses for purposes 1 and 2 might be rarer occurrences; once the technology is established for purpose 3, its indications will continually expand to cover purposes 1 and 2. Created with BioRender.com.●Bridge-to-anastomosis: An EPS could be used to maintain support of the tissue until transplantation and successful anastomosis to mitigate ischemia/reperfusion injury. This purpose could support the tissues during delays between harvesting and anastomosis such as transportation of composite allografts, temporizing replants, or stabilization of decompensating patients.2,3 ●Bridge-to-neovascularization for traditional flaps: A portable/wearable EPS could be maintained following inset of the tissue over a wound bed and obviate the need to isolate and connect to recipient vessels. Extracorporeal support would continue until sufficient vessel ingrowth and tissue integration has occurred and can be weaned once the neovascularized network itself can provide full tissue support. The basic feasibility of the bridge-to-neovascularization approach in a vessel depleted wound was demonstrated in a small case series and showed that less than 2 weeks of external perfusion could allow sufficient neovascularization.4 ●Bridge-to-neovascularization for bioengineered flaps: The third application has the broadest implications for clinical impact and the field of bioengineered vascularized composite tissues. Currently, although there are limited studies, a major obstacle in engineered vascular networks is thrombosis.5 An EPS would be crucial to ensure successful transfer of engineered constructs with the benefit of closed-system isolated drug delivery (eg, heparin, vasodilatory agents) and conditioned perfusate (eg, platelet depletion) to prevent intravascular thrombosis. Similarly, this closed circuit could be used for delivery of growth factors to induce angiogenesis and facilitate integration of the transferred tissue. In summary, an EPS would address immediate and future problems in complex soft-tissue reconstruction. Recent advancements in the machine perfusion field and its integration with reconstructive microsurgery could open doors for a novel subspecialty. The challenging scenario of extensive tissue loss could be managed without the need for microsurgery using a compact perfusion system. DISCLOSURE The authors have no financial interest to declare in relation to the content of this article.

Technical Considerations in Patients Requiring a Second Microvascular Free Flap in the Head and Neck

To identify the difficulties associated with performing a second free flap reconstruction in the head and neck as well as the techniques used to achieve successful reconstruction. A retrospective review of a prospectively maintained patient database. The study population comprised 33 patients who required a second free flap in the head and neck. Several variables were analyzed in this cohort. Patient-related factors included the following: the availability of recipient vessels, the need to access the contralateral side of the neck, history of neck surgery, history of radiation therapy, and type of free flap used. Complications associated with the reconstruction were also reported. In this cohort of 33 patients, 34 free flap reconstructions were performed. All were successful, and there were no flap-related complications. Owing to the paucity of good recipient vessels in many cases, the contralateral side of the neck was commonly used, but no patients required vein interposition grafts. Second free flap reconstructions in the head and neck can be safely accomplished. We have found that the availability of recipient vessels is the most important consideration in these patients. The dissection of the contralateral side of the neck is often required, but the use of flaps with long pedicles obviates the need for vein interposition grafts. Compared with the success rate in this study, the relevant literature suggests that flap survival rates are lower when interposition grafts are used. Modifications in flap-harvesting techniques and inset geometry can also be used to facilitate insets in complicated surgical fields that have been reoperated on.

Reconstruction of complex oncologic chest wall defects: a 10-year experience.

The repair of complex chest wall defects presents a challenging problem for the reconstructive surgeon. Although the majority of such defects could be repaired with the use of local and regional musculocutaneous flaps, more complicated cases require increasingly sophisticated reconstructive techniques. This study reviews the experience at a single cancer center with chest wall reconstruction over a decade. A retrospective review was undertaken for each patient who underwent chest wall reconstruction from 1992 to 2002. Patient demographics and variables, including pathologic diagnosis, extent of resection, size of defect, method of reconstruction, and outcome were evaluated. There was a total of 113 patients, 88 females and 25 males. The average age was 58 years (range, 19-88 years). The most common diagnoses were breast cancer and sarcoma. The average area of the chest wall defect after resection was 266 cm. One hundred fifty-seven musculocutaneous or muscle flaps were performed for reconstruction of the chest wall. Eleven percent of patients underwent reconstruction with autologous free tissue transfer. One hundred six patients underwent a single operation. Seven patients required a second operation for salvage of a complication. In 19 cases (15%), more than 1 flap was used simultaneously to complete the reconstruction. Eighty-four percent of the patients achieved stable chest wall reconstruction with no complications. Seven patients (4%) had partial (>10%) flap loss. The most common remaining postoperative complications were delayed wound healing (3% of patients), infection (2.5%), and hematoma (2.5%). Immediate chest wall reconstruction is safe, reliable, and can most often be accomplished with 1 operation. A variety of flaps, both single and in combination, could be used to achieve definitive coverage of the chest wall after extirpative surgery. The reconstructive choice is dependent on factors such as size of the defect, location on the chest wall, arc of rotation of the flap, and availability of recipient vessels. Based on this single institutional experience over a decade, an algorithm to chest wall reconstruction is provided.