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Inadequate tissue blood supply (e.g., in a wound or a poorly vascularised graft) can result in tissue ischemia and necrosis. As revascularization is a slow process relative to the proliferation of bacteria and the onset and spread of tissue necrosis, extensive tissue damage and loss can occur. Necrosis can spread rapidly, and treatment options are limited such that loss of tissue in ischemic tissue following necrosis onset is considered unavoidable and irreversible.Oxygen delivery from biomaterials exploiting aqueous decomposition of peroxy-compounds has shown some potential in overcoming the supply limitations caused by quite short oxygen diffusion distances in tissues by creating higher concentration gradients than can be attained by air saturated solutions or by distributing oxygen supply throughout a scaffold or construct by using particulate formulations. These have found application in tissue preservation, bioinks, creation of 3D tissue analogues etc. In preclinical models among the more exciting reports was a single study demonstrating reduction of ischemic skin necrosis albeit only short term using short term sub dermal delivery of oxygen below ischemic skin flaps. To explore this effect further, we developed an implantable solid peroxide-biomaterial based system with reduced hydrogen peroxide release by virtue of incorporation of minerals to catalytically decompose it in a much longer flap than examined previously. Blood flow in this flap reduced from essentially normal to essentially zero, along its 9cm length. Without treatment ∼50% of the total flap was necrotic in 2-4 days. In both groups, complete necrosis in the distal third of the flap with no observable flood flow was observed. But in the middle low blood flow region of the flap, treatment did prevent necrosis. This study indicated that subdermal oxygen delivery alone cannot completely mitigate dermal necrosis if no blood flow is present, but it could improve the survival of partially tissue at least in the short term which could find application to augment conventional treatments or to gain time until surgical intervention.

Perineal carcinoma of unknown primary origin (CUP) is a rare entity and represents a diagnostic and therapeutic challenge. These tumors may respond well to a combination of surgical resection, when feasible, local radiotherapy, and platinum-based systemic chemotherapy. A 67-year-old male patient consulted for urinary discomfort associated with perineal abscess. The perineal abscess was drained, and the patient was diagnosed with perineal carcinoma of unknown origin. Computed tomography (CT) scan shows a large perineal mass that involves both corpora cavernosa and corpus spongiosum. CT and bone scan excluded the metastatic spread of the disease. Inguinal lymph nodes were not identified. The surgical treatment consisted of two different phases. Phase I: the perineal mass exeresis with total penectomy. Phase II: perineal neourethrostomy with double oral mucosa graft. Coverage of the perineal defect and morphological reconstruction of the penis with fasciocutaneous and gracilis flap. The surgical intervention lasted for nine hours and the estimated blood loss was 500cc. The patient was discharged twelve days after the intervention. Later he received adjuvant treatment with immunotherapy (Cemiplimab) because was not subsidiary to treatment with platinum for renal failure. The patient died after nine months of follow-up due to pulmonary and abdominal metastatic spread.