Mr. E is 80 years old. He presented to the author’s wound clinic with a chronic, nonhealing ischemic wound on his left lateral lower extremity that had been present for 4 months after he sustained a fall. His medical history included type 2 diabetes for 14 years (HgbA1c 7.5%). He also had hypertension, COPD, PAD, and lung cancer in remission. Mr. E initially was treated in a different wound clinic, but after 2 months, he was referred to the author’s wound clinic for continued wound care.
Previous treatment. At the first wound clinic, Mr. E’s wound initially measured 3.5 cm x 2.6 cm with a depth of 0.2 cm. Daily dressing changes consisted of 0.9% normal saline-soaked cotton gauze. After 4 weeks of treatment, Mr. E was referred to a vascular surgeon for assessment, which revealed the absence of pulses in bilateral posterior tibial and dorsalis pedis arteries as well as diminished bilateral popliteal pulses. A pulsed volume recording (PVR) demonstrated right and left iliac artery stenosis. Mr. E’s ankle brachial index (ABI) was 0.63 on the left lower extremity and 0.59 on the right lower extremity. He underwent an angiogram, but lesions in the iliac arteries were not amenable to intervention. Results from the vascular assessment included a strong recommendation against surgical intervention except as a last resort, secondary to Mr. E’s complex comorbidities and his inability to endure the physical demands of surgery. As a result, if his wound did not heal, his only option was a below-knee amputation of the left lower extremity.
After 6 weeks of treatment consisting of sharp debridement with daily dressing changes with 0.9% saline, Mr. E’s wound increased to 4.1 cm x 2.6 cm with a depth of 0.9 cm, with two tracts at 6 o’clock and 7 o’clock measuring 0.8 cm and 1.6 cm, respectively. A swab culture of the wound surface was performed at this point and the primary dressing was changed to a Hydrofiber™ (Aquacel Ag, ConvaTec, Skillman, NJ) dressing containing ionic silver. Mr. E’s caregiver performed daily dressing changes at home. After 2 weeks, the primary dressing was changed to 0.1% gentamicin sulfate, applied three times daily and covered with an appropriate secondary dressing, due to identification of Staphylococcus aureus from the wound culture. Mr. E then was referred to the author’s wound clinic for continued care.
Study treatment. During the initial visit to the author’s clinic, Mr. E’s wound measured 3.0 cm x 2.0 cm with a depth of 0.3 cm, and a tract at the 5 o’clock position measuring 0.5 cm; all previous treatment notes were reviewed. Mr. E was performing dressing changes at home as previously directed by his initial wound clinic. A swab culture of the wound surface at his initial visit to the author’s clinic showed no evidence of S. aureus on the wound surface, so gentamicin sulfate ointment use was discontinued 1 week later. At this point, Mr. E was assessed by a plastic surgeon for a potential skin graft, but he was deemed “not an appropriate candidate” for intervention secondary to his extensive circulatory impairments.
Using the treatment chart notes, percent change in wound area during the previous 4 months was calculated (initial area – follow up area/initial wound area x 100%). Because wound response during hydrofiber treatment was most encouraging (see Table 1), the hydrofiber dressing with ionic silver was started as the primary dressing. In addition, after 2 weeks TENS therapy was initiated. Figure 1 depicts Mr. E’s wound at the initiation of TENS treatment 2 weeks after the initial assessment at the authors’ wound clinic. Wound measurements had remained unchanged as compared to measurements at his initial visit, and due to the formation of a thick layer of adherent devitalized tissue, the wound’s depth and the previously mentioned tract at the 5 o’clock position were obscured.
Because of the poor level of perfusion in Mr. E’s left lower extremity, TENS was chosen as the only potential treatment available to increase blood flow to the wound and surrounding area, as evidenced in the findings published by Cosmo et al.13 In keeping with these findings, treatment settings were selected to match published settings as much as possible. The LogiSTIM® TN-11 unit (US Medical Minnetonka, MN, see Figure 2) was set to deliver a 2Hz biphasic, symmetric waveform through the periwound area at an amplitude of 33mA with a pulse width of 250 microseconds. The TENS unit allows settings, such as the signal frequency of 2Hz and the biphasic, symmetric waveform, to be “fixed” and remained unaltered by the patient. Only the amplitude could be adjusted to control the current flowing from electrode to electrode, rendering the patient responsible for the correct settings.
To ensure uniform treatments and proper machine settings, Mr. E received extensive initial training that included machine function, construction, basic maintenance, and required settings. The initial phase of patient training provided by the physical therapist involved the following steps: 1) demonstrating how electrodes were placed 2 cm superior and inferior to the wound margin by outlining the desired location on the lower extremity with a skin pen; 2) turning the TENS unit on and setting the signal amplitude to the desired parameter of “33” as seen on the TENS unit display (accomplished through simple push button manipulation); and 3) turning the unit off and disconnecting the leads from the electrodes. At this point, the electrodes remained fixed at their designated location for the initial phase of training.
Phase two of Mr. E’s training involved the patient repeating each of the previous steps he had been shown to ensure he would be able to administer treatments correctly at home. He repeated this process four times until he was able to complete all steps correctly and without hesitation. Mr. E then was required to teach the entire process to his caregiver with clinician supervision, from electrode installation through treatment and after care. The therapist evaluated the caregiver’s aptitude to ensure there were no gaps in the caregiver’s knowledge. This allowed two sets of trained eyes to verify each treatment, including those given at home. Effectiveness of this phase was measured by repeat demonstration across several visits at the clinic. As the education and treatment process progressed, Mr. E and the caregiver were trained in after-care instructions, safety precautions, and how to recognize atypical signs and symptoms of treatment. The treatment protocol was reviewed at each clinical visit to ensure the parameters of treatment were being followed correctly. Treatment time was 45 minutes, twice per day. The waveform was biphasic and symmetric; therefore, positive/negative electrode placement was inconsequential. Electrode connectors were accessible on the exterior of the dressing for ease of connection to prevent dressing from being disturbed.
The wound dressing was changed and the electrodes were removed to allow for skin inspection during Mr. E’s weekly clinic visits. New electrodes were applied to ensure proper electrical contact was maintained and to reduce the potential for infection. Treatment consisted of wound irrigation with 0.9% normal saline with pulsatile lavage (8 psi) and concurrent suction (160 mm Hg). This approach was used to irrigate the wound base and wound margin and to loosen devitalized tissue in preparation for conservative, sharp, selective debridement. The requirement for conservative, sharp, selective debridement was determined on a visit-by-visit basis and was provided only as required in order to maintain a wound bed free of devitalized tissue that could hinder the wound’s ability to contract and heal. At each visit, the hydrofiber silver dressing was re-applied with an appropriate secondary dressing for exudate management and conformal gauze.
Pain was assessed at each treatment session using the visual analog scale. Pain was assessed as an adjunct to wound healing and while it gave no specific indication of wound status, a reduction in pain was viewed as an overall positive sign.
A reduction in wound size of length, width, and depth was noted at Mr. E’s fourth treatment visit. Further reduction in wound size occurred at each visit until the wound was completely resolved at week 12 (see Figure 3). As wound healing continued, a hydrogel was added to maintain a moist wound healing environment with the silver-containing hydrofiber dressing until Mr. E’s wound was closed with 100% epithelial tissue (see Figure 4).
Once the wound was deemed closed, an ABI was performed with a result of 0.71 on the left lower extremity and 0.57 on the right lower extremity. An ABI also was performed at Mr. E’s 1-month follow-up with a result of 0.80 on the left and 0.57 on the right side. At the 1-month follow-up assessment, Mr. E was provided a light compression stocking (10–12 mm Hg) to prevent edema and decrease the potential for wound recurrence and TENS was discontinued. As of his 6-month assessment, Mr. E has no wounds and has continued use of light compression. With continued routine medical assessments, his prognosis is positive.