Decellularized Human Skeletal Muscle as Biologic Scaffold for Reconstructive Surgery.

Engineered skeletal muscle tissues have been proposed as potential solutions for volumetric muscle losses, and biologic scaffolds have been obtained by decellularization of animal skeletal muscles. The aim of the present work was to analyse the characteristics of a biologic scaffold obtained by decellularization of human skeletal muscles (also through comparison with rats and rabbits) and to evaluate its integration capability in a rabbit model with an abdominal wall defect. Rat, rabbit and human muscle samples were alternatively decellularized with two protocols: n.1, involving sodium deoxycholate and DNase I; n.2, trypsin-EDTA and Triton X-NH4OH. Protocol 2 proved more effective, removing all cellular material and maintaining the three-dimensional networks of collagen and elastic fibers. Ultrastructural analyses with transmission and scanning electron microscopy confirmed the preservation of collagen, elastic fibres, glycosaminoglycans and proteoglycans. Implantation of human scaffolds in rabbits gave good results in terms of integration, although recellularization by muscle cells was not completely achieved. In conclusion, human skeletal muscles may be effectively decellularized to obtain scaffolds preserving the architecture of the extracellular matrix and showing mechanical properties suitable for implantation/integration. Further analyses will be necessary to verify the suitability of these scaffolds for in vitro recolonization by autologous cells before in vivo implantation.

Alternative conduits for microvascular anastomoses.

Thrombotic events in vascular substitutes are the main cause of obliteration of most microvascular prostheses and subsequent failure of microvascular anastomoses. The development of new biomaterials for vascular replacement aims to obtain an ideal graft for microvascular surgery. Completely bioresorbable vascular prostheses with the capacity to induce regeneration and growth of a new vascular segment seem to overcome the limitations of contemporary artificial prostheses, mostly made of artificial materials and lacking the capacity to grow and be remodeled. Autologous vessels are currently the most used material for small-diameter arterial replacement. Immune acceptance is a major advantage offered by this technique, but the time required is a limitation in emergency surgery. The need for a prosthetic graft that would have the same properties as a small-diameter conduit has led investigators to pursue many avenues in vascular biology. This article details the development of microvascular synthetic prostheses, clarifying the current status and the future aims.

"Synchronous" multifocal necrotizing fasciitis.

BACKGROUND: Necrotizing fasciitis (NF) is an infection of the soft tissue, and is fatal if not promptly and aggressively treated. Although it is rare, it is not exceptional; nevertheless, its presentation may be misleading and may delay the diagnosis. We highlight the possible synchronous development of NF in multiple noncontiguous areas. CASE REPORT: A 44-year-old diabetic man with no history of trauma complained of nonspecific lower back pain, which he treated with analgesics and oral antibiotics. Erythema at the left arm appeared, and the general condition worsened. The patient was admitted to the Emergency Department, and NF was diagnosed at the right gluteus and left arm. CONCLUSION: "Synchronous" multifocality is not an expected presentation of NF, and it complicates the diagnosis and delays treatment, with a potentially negative impact on outcome.

Reconstruction with bilateral posteromedial thigh (PMT) flaps after Fournier's gangrene.

Fournier gangrene (FG) is a deadliest condition affecting genitoperineal area in predisposed patients. A late diagnosis, thus a delayed surgical treatment, leads often to death. LRINEC score and CT scan can help in suspect, despite definitive diagnosis needs surgical exploration and histological findings. Furthermore, FG determines wide defects of genitoperineal area, thus reconstructive surgery is pivotal to restore form and function of the affected patient. Aim of this article is to discuss the use of posteromedial thigh (PMT) fasciocutaneous flap in FG reconstruction, based on authors' personal experience. A case report of a 63-year-old obese and diabetic man is presented. Two PMT flaps (10 x 17cm2) were harvested to cover a complete scrotal defect (20 x 40cm2), while penis integuments defect was treated with a two-staged surgery (dermal substitute application and skin graft). Follow-up at 4 months showed a successful outcome of PMT flaps reconstruction, with preservation of testes vitality, despite one of the flaps developed distal necrosis that was treated with further debridement and skin graft. The authors experience is followed by the decision-making process based on a literature review that led to the choice to use PMT flaps to achieve reconstruction. Furthermore, alternative flaps to treat FG, each of them with pros and cons, are discussed, despite there is not a gold standard treatment and every option must be tailored to the patient. KEY WORDS: Fournier gangrene, Genital reconstruction, Infection, Necrotizing fasciitis, Posteromedial thigh flap, Perineum reconstruction.

Burn Unit admission and management protocol during COVID-19 pandemic.

BACKGROUND: The actual epidemic outbreak is the third time in the last two decades in which a coronavirus results in a major global spread with serious consequences in terms of vastity of affected patients, life losses, health system organization efforts and socio-economic implications. Lacking effective therapies and vaccinations, during viral outbreak the major and most incisive mean for viral spread control is spread prevention, especially for the fragile burn-injured patients we are called to care for in Burn Units. METHODS: We developed an admission and inpatient management protocol to preserve burn patients from SARS-CoV-2 contagion, in order to avoid additional morbidity and mortality in patients with already compromised health conditions. Data from burn-injured patients admitted to our Unit following this new protocol were retrospectively analyzed in order to verify its effectiveness in prevention of viral spread. RESULTS: From the 8th of March to the 8th of June, we admitted 18 patients in the Burn Unit ICU and semi-ICU and 17 patients in the Burn Ward. Two of them resulted positive to COVID-19 nasopharyngeal swab and bronchoalveolar lavage collected immediately on admission, for both the extension of burns and their general clinical conditions implied ICU admission. Moreover, a caregiver of an admitted child resulted positive to the nasopharyngeal swab. No other cases of SARS-CoV-2 positivity have been reported neither between hospitalized patients nor between healthcare workers. CONCLUSION: The evidence of high ICU admission rate and high mortality in patients affected by SARS-CoV-2 combined with the fragile clinical conditions of burn patients required the development of an admission and hospitalization management protocol.

Comparison of reasorbeable mini anchor versus non reasorbeable: histological evaluation in an experimental rabbit model.

PURPOSE: Experimental animal study to evaluate the osseo integration, inflammatory response, dislocation and the reabsorption timing of the reasorbeable Mitek(®) mini anchor, in comparison with the non reasorbeable titanium based. METHODS: TWENTY RABBITS WERE USED: divided into two groups of ten. Each animal underwent sectioning and reinsertion of the Achilles tendon bilaterally, using a reasorbeable mini anchor on one side and a controlateral non reasorbeable mini anchor. The first group was sacrificed after 40 days and the other after 120 days. The bone tendon complex was subjected to histological study. RESULTS: No histological and statistical significative difference were observed in each group, with a lower inflammation response in the reasorbeable implant. Electronic microscopy evaluation demonstrates good stability of the implant in each group. At day 120 the reasorbeable anchors were not yet disappeared. CONCLUSION: Reasorbeable Mitek mini anchors are to be considered to guarantee a similar response and similar bone stability than non reasorbeable ones.