External Tissue Expansion (Proxiderm)
I wanted to talk about a method of wound closure that deserves to be in the toolkit of any trauma or reconstructive surgeon who faces difficult wounds. I have no commercial involvment with Progressive Surgical, which is the company that makes the Proxiderm external tissue expansion device.
Each Proxiderm device has two opposing tissue hooks which are separated on tension and inserted away from the wound edges. The device applies a specific amount of tension on the tissue (460g) which causes steady expansion of the tissue without pressure necrosis. Technically, a similar procedure is possible using a serial-suturing technique with rubber bolsters, but the disadvantage of this is the variability of the tension being applied. With Proxiderm, it is designed to provide the right amount of force every time.
By placing these devices every 2-3 cm along the wound edges, and changing them every 2-3 days, wounds can be gradually closed with good skin, not needing grafting or flap procedures. Wounds need to be well debrided prior to beginning the procedure, and are generally recleaned with each stage, when new Proxiderms are applied and the old ones discarded. The following photos (from the company website at www.proxiderm.com) show a tough lower extremity wound closed at 16 days without the need for grafts or flaps.
The procedure can be done as an outpatient, and it is necessary to secure each device with a suture across the wound and tied over the top. A well-padded, bulky dressing is also a must.
For more information, head to www.proxiderm.com, which is filled with detailed information and many more case photos.