The Effects of Intermittent Negative Pressure on Wound Healing and Peripheral Circulation in Spinal Cord Injured Subjects

This is a pilot study to evaluate the treatment effect of INP on wound healing and tissue perfusion for a larger randomized controlled trial (RCT). This randomized cross-over pilot study will look at the effects of intermittent negative pressure (INP) therapy wound healing and the peripheral macro- and microcirculation in spinal cord injured patients with chronic leg and foot ulcers (6 weeks or more at inclusion). The project is designed as a randomized clinical trial with single-subject multiple baseline design. We will perform convenience sampling of spinal cord injured patients with leg and foot ulcers, with the last recruitment by the end of december 2016.To ensure equal distribution of participants in each study arm, we will perform block randomization. A statistician will randomized patients to either intervention arm or control arm before start of the study: At baseline, each participants will be randomized into either A) 8 weeks without intervention OR B) 8 weeks with start INP therapy 2 hours per day divided into 2-3 timed sections. After the 8 weeks, participants in the the control group (A) will be re-examined, and start 8-week INP therapy. Also the intervention (INP) will be subjected to the same lower limb in each individual throughout the study period. The other leg will act as a intra-individual control.

At baseline (week 0), and during the course of the study (every 4th week), the participants' wounds will be measured by a wound nurse. Baseline (before start of INP therapy) and after intervention the following measures will be performed: Demographic data (weight, height, ABI), Segmental pulse-volume-recording, Segmental skin perfusion pressure with a laser Doppler sensor and a pressure cuff to evaluate reactive hyperemia (Sensilase, Väsamed) and health surveys (SF-36/EQ-5D-5L and customized wound questionnaire) or similar will be examined at baseline and and the end of the study period. Otivio AS has supplied the FlowOx devices and provided the necessary training to perform this project. Outcome variables assessed before and after the study period will be: wound healing (primary endpoint), quality of life (secondary endpoint), skin perfusion pressure (secondary endpoint), ankle-brachial pressure (secondary endpoint) and segmental pulse-volume recording (secondary endpoint). The aim of this project is to prospectively examine and elucidate the effect of intermittent negative pressure therapy applied to a limited part of the lower limb on clinically relevant measures related to wound healing and peripheral macro- and microcirculation in patients with spinal cord injury.

The hypotheses of the study are:

* Application of INP in patients with spinal cord injury, by the use of the FlowOx™ device, will improve wound healing in the foot compared to before treatment (baseline) and compared to standard wound care alone.
* Application of INP in patients with spinal cord injury, by the use of the FlowOx™ device, will improve macro- and microcirculation in the foot compared to before treatment (baseline) and compared to standard wound care alone in patients with spinal cord injury.
* Application of INP in patients with spinal cord injury, by the use of the FlowOx™ device, will improve macro- and microcirculation in the intervention foot compared to the control foot and compared to standard wound care alone in patients with spinal cord injury.


Eligibility Criteria:
We will perform convenience sampling of spinal cord injured patients with leg ulcers, recruited through health professionals affiliated with Sunnaas Rehabilitation hospital.

Inclusion Criteria:

* Able and willing to provide informed consent
* Age: 18-96 years
* Affected foot/shoe size \<46 (approximate foot length\< 29,5 cm)
* Spinal cord injury preferably with a non-healing leg/foot ulcer/pressure wound for more than 6 weeks

Exclusion Criteria:

* Incapable to consent voluntarily, i.e. patients who are not able to consent due to their mental status, or who are not willing or able to perform the negative pressure therapy in a sitting position
* Not adhering to the INP therapy program
* Patients with an expected life-span less than 3 months
* Patients in which a deep venous thrombosis or pulmonary embolism is suspected
* Bilateral amputation of lower extremity