Chronic wounds on the lower leg and foot have multiple etiologies that include vascular disease: venous leg ulcers (VLU), diabetic with neurotropic and/or ischemic foot ulcers (DFUs) along with ulcers due to peripheral artery disease (PAD). Although the underlying causes of the ulcers differ, the result of the underlying problems in each case is an impact on the microcirculation in the lower leg and in the region of the ulcers.

The pathway to the altered microcirculation is different with each type of ulcer:

• PAD ulcers – reduced blood flow due to arterial stenoses or occlusions in the arteries taking blood to the leg, and changes in the small vessels

• DFU – increased pressure on the skin and compression of the blood vessels in the skin due to the underlying neuropathy, the inability to feel pain from the sustained pressure, and the inability to subconsciously make adjustments to relieve the pressure. The microcirculation can also be impacted by changes in the small vessels in the skin or the larger vessels in the leg due to the impacts of diabetes on the blood vessels

• VLU – ambulatory venous hypertension due to an inefficient calf muscle pump that results from changes in the veins. This alters the microcirculation in the ulcers and the surrounding skin

Treatment of these types of lower limb ulcers focusses on treating the underlying cause which has the goal if improving the microcirculation of the ulcers and in the skin around the ulcers. The standard treatment methods are:

• PAD ulcers – reconstruction of the occluded or stenosed arteries to improve circulation to the limb and microcirculation to the ulcers including surrounding tissue

• DFU – pressure offloading to reduce pressure on the skin and its microcirculation to allow increased blood flow. Where appropriate, vascular reconstruction to correct arterial stenosis or occlusion

• VLU – compression therapy on the lower leg to reduce ambulatory venous hypertension and improve microcirculation of the tissue in and around the ulcer

In each of these forms of ulceration, treating the underlying cause improves the microcirculation, however, there are frequently still residual impairments in the circulation that are not fully improved. This adds to the challenges of healing in some of these chronic wounds. In addition, some patients are not able to undergo optimal treatment due to the extent of their underlying disease, difficulty tolerating the optimal treatment, or lack of access or delays in receiving appropriate care. For this reason, there is a need for other ways to improve the microcirculation in and around their chronic wounds.

The Muscle Pump Activation device (MPA – geko, Firstkind, United Kingdom) is an innovative device that has improved both venous blood flow in the lower limb, and the microcirculation in healthy volunteer. In addition, similar improvements have been documented in patients with chronic leg ulcers that include VLU, DFU and PAD ulcers. There is also a growing body of evidence documenting MPA benefits accelerating the healing of other chronic wounds.

With the growing evidence for the use of this innovative treatment, there is good reason for clinicians to use this device for managing their patients. Some of the current indications include:

• VLUs – patients who are unable to tolerate optimal compression or whose ulcers are not reducing in size or are not achieving the expected size reduction of 30 per cent after 4 weeks with optimal compression

• DFUs – patients whose ulcers are not reducing in size or are not achieving the expected size reduction of 30 per cent after 4 weeks with appropriate pressure off-loading, treatment of secondary infection and optimization of arterial blood supply

• PAD ulcers – patients whose arterial disease is not amenable to vascular reconstruction (exhausted all vascular reconstruction options, unable to receive vascular reconstruction due to other medical conditions or problems with access to care). This treatment would be applicable to patients who have significant delays in treatment due to remote locations

The MPA device is an innovative technology that provides health care providers with a validated patient management option with chronic lower limb ulcers. It stimulates the peroneal nerve with an ankle twitch response associated with local increased perfusion. This is a tool that clinicians should incorporate into their management strategies for patients with VLUs, DFUs and PAD ulcers.

By Dr. Michael C Stacey and Dr. R Gary Sibbald
Dr. Michael C Stacey is a Vascular Surgeon at Hamilton Health Sciences, McMaster University and Dr. R Gary Sibbald is a Dermatologist at Women’s College Hospital, University of Toronto.