Porcine heterografts in dermatologic surgery and reconstruction

New strategies for sterilization and preservation of fresh fish skin grafts

The introduction of fish skin as a biological dressing for treating burns and wounds holds great promise, offering an alternative to existing management strategies. However, the risk of disease transmission is a significant concern. Therefore, this study aimed to examine how established sterilization and preservation procedures affected fish skin grafts' microbiological and histological properties for long-term usage. Lyophilization of the fish skin graft followed by rehydration in normal saline for 15 min did not change the collagen content. Furthermore, gamma irradiation of the lyophilized fish skin graft at different lengths 5, 10, and 25 KGy showed a significant reduction in microbial growth (aerobic bacteria, aerobic yeasts, and fungi) at 15- and 30 days after the irradiation. However, exposure to 10 KGy was found to be the most effective intensity among the different gamma irradiation lengths since it preserved the collagen fiber content and intensity in the lyophilized fish skin grafts at 15- and 30 days after the irradiation. These findings provide efficient preservation and sterilization methods for long-term usage of the fresh Tilapia skin grafts used for biological dressings.

Bilateral Forehead Rotation Flap with Skin Substitute Application for Convexity Replacement

Large forehead defects pose reconstructive challenges, considering the tissue inelasticity and the need to preserve symmetry of the eyebrow and hairline. Local skin flaps and primary closures are mainstays of forehead reconstruction with many techniques reported, but they may not cover the entire defect. Further closure options with acceptable cosmesis are limited. While providing a functional alternative, skin grafting may take on an atrophic concavity and shiny texture. Free flaps similarly may not accurately replicate the contour of the forehead and may be discordant with the texture of adjacent skin. We describe a reproducible technique for closing a large central forehead defect in a single-stage local flap while retaining symmetry of eyebrows and neurovascular integrity. We also propose serially applying a skin substitute to the remaining portion of the defect to recreate forehead convexity and potentially expedite healing. This technique may represent a viable and reproducible method for recreating the natural contour of the forehead when complete closure may not be an option.

The Role of Lyophilized Xenodermotransplants in Repairing the Atria's Structure and the Peculiarities of Regenerative Processes after Thermal Trauma in an Experiment

The effects of severe burn injuries on the cardiovascular system, specifically the atria and auricles of the heart, were investigated. The potential benefits of using lyophilized xenodermotransplants as a treatment option were also evaluated. The experiments were conducted on adult guinea pigs divided into three groups: intact animals, animals with burns, and animals with burns who underwent early necrectomy followed by wound closure with lyophilized xenodermotransplants. Third-degree burns caused significant ultrastructural changes in atrial cardiomyocytes, leading to long-term destructive changes in the structural components of the atria. However, the use of lyophilized xenodermotransplants had a positive effect on the atrial ultrastructure over time. This study highlights the complex and varied effects of burn injuries on the body and the potential benefits of lyophilized xenodermotransplants in treating severe burn injuries. By preventing destructive changes in the heart and activating regenerative processes, lyophilized xenodermotransplants can improve the condition of the heart after thermal injury. Further research and development in this area are necessary for understanding the potential of lyophilized xenodermotransplants in tissue repair and regeneration.

Comparing the application of various engineered xenografts for skin defects: A systematic review

INTRODUCTION

Xenografts are a now a cornerstone in the management of wound dressings. Promising results were achieved since 1960 in the application of skin substitute for skin defects.

OBJECTIVE

The objective of this study was to evaluate the efficacy of various xenografts.

METHODS

A literature research was conducted using the following query: 'Porcine skin dermatology substitute', 'bovine skin dermatology substitute', 'xenograft skin substitute dermatology', 'xenografts skin defect', 'porcine skin defect', 'bovine skin defect'.

RESULTS

The review yielded 35 articles pertaining to the topic. Main indications for porcine and bovine xenograft application were burn wounds and post-traumatic wounds, respectively. Mean discharge date or length of stay was at the 6th day after porcine application, and the time of graft healing was reported for 33.7% (n = 510) of patients. Promising results were seen with Matriderm and split-thickness skin graft. Most wounds achieved an excellent cosmetic result with full range of motion and a smooth contour appearance. A great variety of tissue substitutes exist, and the choice of graft application should depend on a patient's factors, product availability, wound type, size, and physician's factors.

CONCLUSION

In summary, xenografts are more economic and affordable but have higher risk of infections compared to allografts.

Utility of Porcine-Derived Xenograft as an Adjunct to Split-Thickness Skin Grafting in Lower-Extremity Wounds

OBJECTIVE

Porcine-derived xenograft biological dressings (PXBDs) are occasionally used to prepare chronic wound beds for definitive closure before split-thickness skin grafts (STSGs). We sought to determine whether PXBD influences rate of STSG take in lower-extremity wounds.

METHODS

Lower-extremity wounds treated with STSGs were retrospectively reviewed. Patients were included in one of two groups: wound bed preparation with PXBD before STSG or no preparation. Patients were excluded if they received wound bed preparation via another method. Patient demographics, comorbidities, wound history, wound bed preparation, and 30- and 60-day outcomes were collected.

RESULTS

There was no difference in healing outcomes between the PXBD (n = 27) and no preparation (n = 39) groups. At 30- and 60-day follow-up, percentage of STSG take was not significantly different between groups (77.9% versus 79.0%, P30 = .818; 82.2% versus 80.9%, P60 = .422). Mean wound sizes at these follow-up periods were not different (4.4 cm2 versus 5.1 cm2, P30 = .902; 1.2 cm2 versus 1.1 cm2, P60 = .689). The PXBD group had a higher mean ± SD hemoglobin A1c level (8.3 ± 3.5 versus 6.9 ± 1.6; P = .074) and age (64.9 ± 12.8 years versus 56.3 ± 11.9 years; P = .007) versus the no preparation group.

CONCLUSIONS

Application of PXBDs for wound bed preparation had no effect on wound healing compared with no wound bed preparation. The two groups varied only by mean age and hemoglobin A1c level. The PXBD may be beneficial, but these results call for randomized controlled trials to determine the true impact of PXBDs on wound healing. In addition, PXBDs may have utility outside of clinically oriented outcomes, and future work should address patient-reported outcomes and pain scores with this adjunct.

Surgical Treatment of Pyoderma Gangrenosum with Negative Pressure Wound Therapy and Skin Grafting, Including Xenografts: Personal Experience and Comprehensive Review on 161 Cases

Significance: Pyoderma gangrenosum (PG) is a rare debilitating autoinflammatory ulcerative skin disease. No gold standard has been established for the treatment of PG. The role of surgical interventions and negative pressure wound therapy (NPWT) was discussed controversially until recently as these procedures might pose a trigger to further aggravate the condition. Recent Advances: Recent advances confirm the paradigm change that a surgical approach of PG with split thickness skin grafting (STSG) secured by NPWT is a safe and valuable treatment if performed under adequate immunosuppression. We elaborate this on the hand of a broad literature search retrieving 101 relevant articles describing 138 patients complemented with our personal experience on 23 patients, including 2 patients treated with a porcine xenodressing. Critical Issues: A wide range of surgical approaches have been reported, including xenografts. Treatment was finally successful in 86%, including the xenotransplant cases. Ten percent improved and failures were mainly reported without immunosuppression. Despite halting the inflammatory process, NPWT alone, without skin grafting, does not much accelerate healing time. The best surgical approach appears to be STSG fixed with NPWT as this leads to higher skin graft take. There remains the problem of the chronic nature of PG and the recurrence after tapering of immunosuppression or trauma; therefore, a sustained immunosuppressive treatment is suggested. Future Directions: While surgical treatment is supported by the published data, the exact immunosuppression is still evolving. Due to deeper insights into pathogenesis and growing clinical reports, a broader utilization of biologic treatments and a shift from tumor necrosis factor (TNF)-alpha to interleukin (IL)-12/23 or IL-23 antibodies alone are predictable, as IL-12/23 antibodies show good clinical responses with fewer side effects. The positive results with porcine xenodressings might be due to immunological effects of the xenomaterial; they appear promising, but are preliminary and should be confirmed in a larger patient collective.

Use of Porcine Xenografts in Dermatology Surgery: The Mayo Clinic Experience

BACKGROUND

Knowledge regarding the use of xenografts in cutaneous surgery is limited.

OBJECTIVE

We sought to better understand the utility, outcomes, and complications of porcine xenograft applications in cutaneous surgery.

METHODS AND MATERIALS

A single center, retrospective study of patients with porcine xenograft applications was completed. Characteristics of tumors, surgical procedures, resulting wound beds, follow-up care, and final length of follow-up were determined, and statistical analysis was conducted.

RESULTS

Of 225 porcine xenograft placements in 220 patients, the majority of tumors were nonmelanoma skin cancers (89%) and similarly divided between the head (excepting nose/ear), nose, ear, and extremities. Both Mohs and standard excision resulted in a 5.7 cm mean area of surgical defect, with the majority closed by porcine xenograft only (84.1%), and healing by secondary intention (97.3%). The area of surgical defect and topical antibiotics contributed to increased length of time to final follow-up.

CONCLUSION

The data represent the largest series of biologic dressings in cutaneous surgery and demonstrate the applicability and safety of porcine xenografts. We recommend consideration of porcine xenografts in the appropriate clinical context, to augment secondary intention.

Porcine xenografts vs. (cryopreserved) allografts in the management of partial thickness burns: is there a clinical difference?

Porcine xenografts and cryopreserved allografts are used for the management of partial thickness burns and both biological materials have strong advocates with regard to clinical performance, the possibility of disease transfer from donor to recipient and other clinical aspects. A literature analysis was performed in an attempt to investigate whether true (statistically significant) differences exist on clinical performance and on other determinants for use. Comparing the results of this study with a similar, previously published study performed on possible differences amongst different types of allograft in the management of partial thickness burns, both allografts and porcine xenograft seem to perform equally well clinically with regard to healing related outcomes. In addition, the risk of disease transfer, in real life, was shown to be minimal. Consequently, clinical aspects being equal, other aspects such as price and availability should be used to decide which material to use for the management of partial thickness burns.

Enxertia de pele em oncologia cutânea

Em oncologia cutânea depara-se freqüentemente com situações em que a confecção de um enxerto é uma boa alternativa para o fechamento do defeito cirúrgico. Conhecer aspectos referentes à integração e contração dos enxertos é fundamental para que os cirurgiões dermatológicos procedam de maneira a não contrariar princípios básicos do transplante de pele. Os autores fazem uma revisão da classificação e fisiologia dos enxertos de pele, acrescendo considerações cirúrgicas determinantes para o sucesso do procedimento.

“Xenograft” dressing in the treatment of burns

Biologic dressings (xenografts and allografts) are an integral part of modern burns care. They provide; reduction of pain and adherence without need for additional fixation; antibacterial action that is a function of its adherence; protection against physical trauma; appropriate heat and moisture retention. Allografts are more effective but supply may be severely restricted. Porcine skin is our standard dressing for partial-thickness burns; it also has a role in providing temporary coverage of full-thickness defects and for debriding burns/ulcers.

Postsurgical wound management

Successful outcomes in cutaneous surgery depend on a variety of factors, including preoperative assessment of the patient's health and expectations, intraoperative skill and attention to detail, and managing the postoperative period. Once the procedure is complete, careful selection of dressings, provision of adequate analgesia, judicious management of complications and monitoring the phases of early maturation while providing patient education improve the likelihood of long-term patient and physician satisfaction.