(1) BTM for Full Thickness and Deep Partial Thickness Burns
BTM (Biodegradable Temporising Matrix) is entirely synthetic and has been developed for use as an implantable dressing on complex open wounds (too large to be closed by suturing) and major burns. Following placement onto the wound, blood vessels and fibroblasts migrate into the foam scaffold over three to four weeks (stylised figures). During this time, the fibroblasts manufacture collagen creating a connective tissue scaffold to replace the biodegrading foam, resulting in a dermis-like layer. Once integrated with vascularised tissue, the seal is peeled away (delamination) and the wound surface reconstructed with a split skin graft. Wound cover with BTM therefore offers a reconstruction which is thicker, more durable and more aesthetic than immediate split-skin grafting. In major burns where there may not be enough donor skin available to reconstruct the whole defect in one stage, the BTM strategy allows the wounds to be covered and temporised, creating a neo-dermis while donor sites recover for the harvest of further skin grafts. A five patient human clinical trial is being conducted by Principal Investigator, Professor John Greenwood AM, at the Royal Adelaide Hospital. The performance of the BTM and data collected from this trial will be used to assist in the protocol design for larger multi-centre burn trials. For further information on this trial click here. PolyNovo has commenced Clinical Trials, for CE certification, at The Alfred Hospital Melbourne and St Anne’s Toulon France. This trial is due to be completed by September 2017. Successful outcomes from this trial will lead to CE certification which will allow regulatory approval throughout Europe, Australia, New Zealand, India and S.E.Asia. PolyNovo is working with MedPass a European-based Contract Research Organisation to oversee this trial.
(2) BTM for Surgical Wounds
The BTM can be implanted into deep and complex wounds that cannot be closed by simple suturing. Such cover is more aesthetic than that offered by immediate split thickness skin grafting, which leaves a depressed wound contour with possible tethering to underlying tendons and a thinner texture appearance than neighbouring skin. This is because the patient integrates the polyurethane foam matrix over a period of weeks prior to split-skin grafting, regenerating a neo-dermal layer which is absent when skin grafts alone are used. Such a wound is exemplified when free flaps are surgically transferred from one area of the body to another. These are deep blocks of tissue containing skin, fat, fascia and/or bone for use in reconstruction of a similarly complex defect created following excision of a cancer, benign mass or trauma. Common sites for flap donation are the thigh, forearm and lower leg. The traditional problems with the forearm donor site are its visible location and aesthetic result with split-skin grafting alone, along with the frequency of skin-graft breakdown exposing the underlying wrist tendon of flexor carpi radialis (FCR), which can lead to prolonged times to wound healing and occasionally resection of the necrotic tendon. Cover with BTM bridges the tendon and prevents its exposure. Visit our YouTube channel- PolyNovo Limited- for videos demonstrating the free movement of tendons under a healed free flap utilising our BTM. (Warning: Some videos are high graphic with surgical content that may disturb people). BTM has now been used as a dermal replacement strategy in two series of free flap donor sites. One series was a clinical trial involving 10 patients and the other was the continued use of BTM under the TGA’s Authorised Prescriber Scheme.