Use of Silicone Gel Liners for Skin Traction and Preservation of Limb Length

The traumatic lower limb amputation offers many challenges to the surgical team. Unlike an elective primary amputation, site selection for limb length is not preplanned and is dictated by the mechanism and extent of injury and soft tissue involvement. Preserving limb length is a primary consideration for the surgeon and of paramount importance for the future functional use of a prosthesis. This is of particular importance when the amputation is in the proximal third of the femur or tibia or the patient is bilaterally involved. Longer bone length can be maintained if adequate soft tissue coverage is possible. If skin coverage is the limiting factor for preserving length and obtaining closure of the primary amputation, either the bone must be shortened or other methods of closure attempted. Closure may be facilitated with skin graft application or secondary closure facilitated by use of a wound vacor serial dressing changes. Recently, traction has been applied as a method to elongate the skin and hasten wound closure without having to shorten the limb.

Traction has been demonstrated to be useful in tissue elongation and wound healing for many years. Traditional skin traction is used to elongate the skin and reduce the surface area of exposed soft tissue. It is achieved by gluing orthopedic stockinette directly to the skin and connecting the stockinette to a traction system on the frame of the bed with 2-5 lbs of weight added. Various traction protocols have been recommended and it stands to reason that the longer the duration of the traction, the better the outcome. Recommendations vary in the number of hours per day, and successful outcomes have been seen when used anywhere from 8-22 hrs/day. Although the benefits of skin traction are will documented, this method has many drawbacks. The dressing is difficult to clean and maintain hygiene, especially if applied to the proximal thigh. The open wounds are inaccessible between dressing changes, making it impossible to assess the skin for problematic symptoms of blistering and wound infection. Significant pain is also commonly associated with the dressing changes and may require intensive pain control methods.

To address the complications associated with traditional skin traction, the use of silicone elastomeric locking liners was attempted in two transfemoral cases at Brooke Army Medical Center. Indications for use of silicone liners include their ability to adhere to the skin and conform to the variations in limb shape without adhesives, their tensile properties that facilitate elongation, ease of repeated reapplications, ease of cleaning without need for replacement, and ease of attaching to current traction systems. Various liners were assessed based on the mechanical characteristics described by Sanders et al. In this application, the liner needed a high coefficient of friction to adhere to the intact skin proximal to the wound site(s), low tensile stiffness to allow significant elongation and maximal stretch under load, no distal matrix or outer fabric that would inhibit elongation, and a distal attachment umbrella. The Iceross™ two-color original locking liner (Ossur North America, Aliso Viejo, CA) was chosen based on these criteria.

In each of the two cases completed, traction time was maximized to approximately 22 hours/day. Traction was removed to allow bathing, toileting, and dressing changes. Traditionally, traction weight for skin elongation is 3-5 lbs. Less than 3 lbs is not effective for tissue elongation and more that 5 lbs often results in blistering of the intact skin. The liners were rolled over the dressings in a manner that prevented distal contact from occurring. Locking lanyard strings (Ohio Willow Wood, Sterling OH) were used to attach the liners to the traction system. Time to wound closure is variable depending on tissue response to treatment. Case 1 took approximately 14 weeks to granulate adequately to proceed with prosthetic fitting. Case 2 remained in traction for approximately 4 weeks with the remaining wound secondarily closed with a split thickness skin graft.

The use of prolonged traction does have significant drawbacks that have to be addressed once the wound healing goal is achieved and traction is discontinued. Traction is applied with the patient supine in bed; therefore other rehabilitation activities are delayed resulting in profound deconditioning, and potential weight gain. Patients with open wounds of the magnitude that would be treated with this technique are often under isolation precautions which intensify the adverse experience of reduced mobility.

In conclusion, it is important to remember this technique requires significant coordination of the treatment team and inconvenience to the patient, but the long term benefits of increased limb length will pay dividends of increased control of the prosthesis. The bilateral transfemoral patient may particularly benefit. In general, most individuals with bilateral transfemoral amputations will anticipate spending increased time either sitting or using a wheelchair for intermittent long distances. The preserved limb length will ease transfers when not using limbs and can reduce localized pressure by increasing the available sitting surface.