Case Report: Surgical Closure of Chronic Soft Tissue Defects Using Extracellular Matrix Graft Augmented Tissue Flaps

Recent Methods for Modifying Mechanical Properties of Tissue-Engineered Scaffolds for Clinical Applications

The limited regenerative capacity of the human body, in conjunction with a shortage of healthy autologous tissue, has created an urgent need for alternative grafting materials. A potential solution is a tissue-engineered graft, a construct which supports and integrates with host tissue. One of the key challenges in fabricating a tissue-engineered graft is achieving mechanical compatibility with the graft site; a disparity in these properties can shape the behaviour of the surrounding native tissue, contributing to the likelihood of graft failure. The purpose of this review is to examine the means by which researchers have altered the mechanical properties of tissue-engineered constructs via hybrid material usage, multi-layer scaffold designs, and surface modifications. A subset of these studies which has investigated the function of their constructs in vivo is also presented, followed by an examination of various tissue-engineered designs which have been clinically translated.

Evaluation of Tissue Apposition and Seroma Prevention in an Ovine Model of Surgical Dead Space Using a Novel Air-Purged Vacuum Closure System

BACKGROUND

Postoperative complications associated with seroma formation resulting from surgical dead space continue to present a challenge in modern surgery. There is an unmet need for new technologies that address surgical dead space as well as prevent seroma formation and associated downstream postoperative complications.

METHODS

The novel implantable tissue apposition and drainage system ENIVO was developed and tested in a bilateral ovine external abdominal oblique (EAO) resection model of surgical dead space. The ENIVO system is a portable powered pump and wound interface featuring air-purged vacuum closure (APVC) that delivers a sustained level of vacuum pressure (80 and 100 mmHg) to the treatment site with an intermittent burst of sterile filtered air through the implanted wound interface. Seroma area, seroma volume, and drain migration were assessed at postoperative days 7 and 14, and all animals were euthanized at day 28 with gross assessment of treatment efficacy including the presence of residual seroma and tissue apposition.

RESULTS

The bilateral model created relatively uniform defects of ~120 cm² following excision of ~30 to 50 g of EAO muscle. Median seroma area of ENIVO-treated defects was statistically smaller than standard of care (SoC)-treated defects at days 7 and 14. Median seroma volume at 14 days was significantly reduced in ENIVO-treated defects relative to SoC-treated defects [1.3 (IQR 0.0-79.5) mL and 188.5 (IQR 27.6-342.9) mL, respectively]. At postoperative day 28, 40% (n = 4/10) of SoC defects showed a residual seroma, whereas in contrast, none of the ENIVO-treated defects showed signs of a residual seroma. Median tissue apposition scoring was higher in the ENIVO treatment group [3 (IQR 3-3)] compared with the SoC group [3 (IQR 0-3)].

CONCLUSIONS

The ENIVO system represents a new approach to dead space management and seroma prevention and was shown to outperform a SoC surgical drain in a challenging large defect model of surgical dead space management and seroma prevention.

Further structural characterization of ovine forestomach matrix and multi-layered extracellular matrix composites for soft tissue repair

Decellularized extracellular matrix (dECM)-based biomaterials are of great clinical utility in soft tissue repair applications due to their regenerative properties. Multi-layered dECM devices have been developed for clinical indications where additional thickness and biomechanical performance are required. However, traditional approaches to the fabrication of multi-layered dECM devices introduce additional laminating materials or chemical modifications of the dECM that may impair the biological functionality of the material. Using an established dECM biomaterial, ovine forestomach matrix, a novel method for the fabrication of multi-layered dECM constructs has been developed, where layers are bonded via a physical interlocking process without the need for additional bonding materials or detrimental chemical modification of the dECM. The versatility of the interlocking process has been demonstrated by incorporating a layer of hyaluronic acid to create a composite material with additional biological functionality. Interlocked composite devices including hyaluronic acid showed improved in vitro bioactivity and moisture retention properties.

Surgical reconstruction of pilonidal sinus disease with concomitant extracellular matrix graft placement: a case series

BACKGROUND

Pilonidal sinus disease (PSD) is a chronic inflammatory disease affecting the soft tissue of the sacrococcygeal region and remains a challenging disease for clinicians to treat. The optimal treatment for PSD remains controversial and recent reports describe several different surgical approaches offering different benefits. Approximately 40% of initial incision and drainage cases require subsequent surgery. Due to high recurrence rates and postoperative complications, a more complex revision surgery involving a flap reconstruction may be required. We hypothesised that the combination of an extracellular matrix (ECM) graft with tissue flap reconstruction may decrease the postoperative complications and recurrence rates for PSD.

METHOD

We report a retrospective case series using a surgical flap reconstruction with concomitant implantation of an ovine forestomach ECM graft under a fasciocutaneous flap with an off-midline closure for recurrent PSD, where previously surgical intervention had failed due to wound dehiscence and/or recurrent disease.

RESULTS

The case series included six patients. After three weeks, all patients except one were fully healed, and the sixth was fully healed by week 4; all wounds remained fully healed at 12 weeks. All patients achieved good cosmesis and were able to return to normal function without any residual symptoms.

CONCLUSION

This pilot case series explored augmenting a flap reconstruction for complex PSD with advanced ECM graft materials, demonstrating that it may improve outcomes and minimise typical complications seen in flap closure, such as inflammation, infection, haematoma/seroma and hypoperfusion. Although the study had a limited number of participants, long-term outcomes were promising and suggest that further studies are warranted.