Are Acellular Dermal Matrices Effective For Grade 0 Ulcers And Fat Pad Augmentation?
When it comes to an extreme load-bearing region on the bottom of the foot, one can surgically address this by placing a piece of graft in the subcutaneous space. Surgeons can perform this procedure on either isolated submetatarsal regions or generally in the ball of the foot or the heel. Preoperative evaluation and medical management are imperative as immunocompromised patients may have difficulty healing.
Step-By-Step Insights On The Procedure
Incision placement depends on the location of the pressure load. However, I prefer the medial or lateral aspects of the foot.
For the first, second or third submetatarsal or the global fat pad, I utilize a medial first metatarsal head incision. I will retract the medial common nerve to the great toe or the medial marginal vein if I encounter these after the incision. Tent and retract the plantar skin, and use a blunt instrument to create a space between the deep dermis and plantar plate. Most of the subcutaneous tissue is lost and there is a natural space that you can enter. You will encounter septal attachments and adhesions from the dermis to the deep layers, and may incise these accordingly.
The graft of preference is a regenerative tissue matrix. Companies such as KCI, Wright Medical, Biomet and Integra provide grafts. There are varying ranges of thicknesses available, typically from 0.45 mm to 2.0 mm. The dimensions of the allograft depend on the size of the area in which you will be inserting the graft. Remember, it is easier to cut away excess than be short.
One would open the graft and allow it to soak for at least 10 minutes although some grafts require a lengthier hydration. Proceed to pass a 2.0 absorbable suture through two distal corners of the free graft and tie a knot, leaving one long end of suture in each corner. Use a Keith needle to pass the suture from the open incision, through the subcutaneous tunnel and out the skin at the far end of the desired graft location. Pulling the Keith needle through the skin and gently pulling the absorbable suture taut allows the graft to shift into place.
A blunt instrument can help guide the graft and allow adequate placement and seating. Tie the two ends of absorbable suture on the outside of the skin anchoring the graft. I have found that there is no need to anchor the graft at the end nearest the incision. Surgeons should take care to avoid kinking, folding, overlapping, bunching or stuffing the graft in the opening. One can insert the graft with it lying in place flat. Finally, irrigate the area and close the skin.
Apply a bulky dressing and allow partial weightbearing in a surgical shoe. One would cut the absorbable suture ends flush with the skin at the second postoperative visit and allow patients to return to a supportive sneaker by week four. The graft ends are palpable and usually the patient can feel the cushion and graft as he or she walks for approximately six weeks.
By the sixth postoperative week, the patient should be back to most normal activities with complete graft integration by 12 weeks.
To help facilitate graft integration, I have utilized Laser Genesis (Cutera).
Laser Genesis is a gradual warming of the dermis that allows for increased blood flow, oxygenation and collagen remodeling. Postoperative complications have included wound dehiscence in one patient. I have not seen graft rejection in my patients who have undergone this procedure.
The remarkable changes noted with the procedure include relief of symptoms and a return to activities that patients could not otherwise perform. I do see a diminished need for pads as well as less potential for non-adherence. Most importantly, the potential lack of progression from Grade 0 ulcerations to more advanced stages is evident.