|Author:||Kwan, Lai Chu Rachel|
|Title:||A comprehensive assessment and management program for diabetic ulcer|
|Subject:||Foot -- Ulcers.|
Diabetes -- Complications.
Electromagnetic fields -- Therapeutic use.
Hong Kong Polytechnic University -- Dissertations
|Department:||Department of Rehabilitation Sciences|
|Pages:||xxvi, 177 leaves : ill. ; 30 cm.|
|Abstract:||Foot ulceration is extremely prevalent in patients with diabetes mellitus, particularly in the ageing population. The lifetime risk of developing a foot ulcer can be as high as 25 percent for people with diabetes (Boulton et al., 2005), in which 11.6% diabetic ulcer persisted unhealed (Jeffcoate et al., 2006). Diabetic foot ulceration is the major cause of high morbidity and mortality among people with diabetes due to high incidence of amputations (Boulton et al., 2005). Persistent hyperglycemia may lead to various complications including decreased sensation, which results in pathological changes in plantar soft tissues, which might stiffen its structure. The altered nerve and blood vessels function, as well as the biomechanical changes in the foot makes diabetic ulcers difficult to heal. Mechanical stresses at the wound site are hypothesized to affect the wound healing (Farahani and Kloth, 2008). It is suggested that the wound might become more extensible during healing process (Lee and Moon, 2003). Early treatment is vital for preventing serious complications such as lower limb amputation. A systematic review was conducted to investigate the effectiveness of electrophysical modalities for managing diabetic ulcers, and found that electrophysical therapy can bring beneficial effects that may promote the healing of diabetic ulcers. Pulsed electromagnetic field was shown to promote nerve regeneration (Musaev et al., 2003) and microcirculation (Webb et al., 2003) in patients with diabetes, thus it is a potential treatment to be used for promoting healing of diabetic ulcer. Therefore, this thesis consists of three inter-related studies. Study I investigated the biomechanical properties of plantar soft tissues in terms of stiffness and thickness among different age groups of healthy people. Study II examined the biomechanical properties of plantar soft tissues in terms of stiffness and thickness among patients with diabetic ulceration and healthy control. Also, the relationship between these properties and tactile sensation were examined in the patients with diabetic ulceration. Specifically, a case study was done to monitor the change of biomechanical properties of the diabetic wound tissues across different stages of healing. Study III was a randomized controlled trial that examined the effectiveness of pulsed electromagnetic field energy (PEMF) in promoting healing of diabetic ulcer by restoring normal biomechanical properties (i.e. stiffness) in the wound tissues, and facilitating microcirculation in the nailfold and pulp of big toes. In Study I, the effect of ageing on the biomechanical properties of plantar soft tissues was examined in sixty healthy volunteers without foot problems, aged from 41 to 83 years. The thickness and stiffness of the plantar soft tissues under the big toe, first metatarsal head, third metatarsal head, fifth metatarsal head, and heel were measured by using tissue ultrasound palpation system (TUPS). The mean stiffness of the plantar soft tissues at the big toe, first metatarsal head, third metatarsal head, fifth metatarsal head, and the heel significantly increased with age (P<0.001). The plantar soft tissues were thickest at the heel (P<0.001), with the thickness increasing with age, although there was no statistical significance between the groups. Significant and strong positive correlations between age and stiffness of the plantar soft tissues were found at the big toe (r=0.608), first metatarsal head (r=0.549), third metatarsal head (r=0.657), fifth metatarsal head (r=0.633), and heel (r=0.584) (all P <0.001).|
In Study II, there were forty-three subjects (9 diabetic ulceration and 34 healthy controls). The biomechanical properties of the plantar soft tissues and the tactile sensation were compared between the two groups. The correlation between these properties and tactile sensation in the patients with diabetic ulceration was investigated. The mean stiffness and thickness of the plantar soft tissues at the big toe, first metatarsal head, third metatarsal head and the heel were significantly different between the diabetic ulceration and the healthy control groups (all P<0.05). In addition to the above measurement sites, the mean stiffness of the plantar soft tissues was also significantly different at the fifth metatarsal head between the two groups. The tactile sensation and mean stiffness of the plantar soft tissues at the big toe, first metatarsal head, third metatarsal head, fifth metatarsal head, and the heel was significantly different between groups (all P<0.05). Fair to strong correlations between tactile sensation and stiffness of the plantar soft tissues were found at the big toe (r=0.618), first metatarsal head (r=0.498), third metatarsal head (r=0.484), fifth metatarsal head (r=0.626), and the heel (r=0.363) (all P<0.05) in patients with diabetic ulceration. In the case study that monitor diabetic wound healing over 7 weeks, the normalized stiffness coefficient of the central wound bed area decreased 9.56% on day 7 and continued to decrease in day 14. It slightly increased by day 21, and finally increased by day 49. The decrease in stiffness of the wound bed tissue in the early stage of healing, allows considerable elasticity of the connective tissue fibers existing as a loose network. At the later stage, the differentiation of fibroblasts cause increase in the stiffness of the wound tissue due to extracellular matrix production and remodelling processes (Grinnell, 1994), and hence the wound bed were found to be stiffer. In Study III, a randomised controlled trial that examined the effects of pulsed electromagnetic fields in promoting the healing of diabetic foot ulcer was conducted. Thirteen subjects (7 for PEMF group and 6 for sham PEMF group) diagnosed with Type II diabetes with unsatisfactory healing of ulcer(s) in the preceding four weeks were recruited. Subjects received either active pulsed electromagnetic field (Duration: 60 minutes; frequency: 12 Hz; and intensity: 12 Gauss) or sham PEMF for 14 sessions within three weeks. Assessment on microcirculation, biomechanical properties of wound tissue and wound healing stages were done at the baseline, after 14 sessions, and one-month follow-up. There was approximately 28% increase in nutritive capillary blood velocity and about 14% increase in capillary diameter in the PEMF group after 14 sessions. Upon the post treatment evaluation, the average stiffness coefficient of the wound bed decreased in both the PEMF group and sham PEMF group; while the PEMF group continued to decrease in average stiffness coefficient at the one-month follow-up, the sham PEMF group showed an increase. The stiffness measured from the wound tissues can serve as quantitative reference for healing stages, and to reflect the degree of growth, remodeling and function of the cells. In conclusion, the biomechanical properties of the plantar soft tissues appear to change with age in healthy individuals. The stiffness of unloaded plantar soft tissues significantly increased with age, also there was a trend of increasing thickness of the plantar soft tissue with advancing age. In addition, the plantar soft tissues of the patients with diabetic ulceration were significantly thicker and stiffer than the healthy controls. Specifically, the change of biomechanical properties was found to correlate with the tactile sensation. The case study showed that during diabetic wound healing, the stiffness of the wound tissues change at different stages. The normalized stiffness coefficient of the central wound bed area decreased at the inflammatory stage, then slightly returned on at the intermediate stage and increased in the later stage. Our randomized controlled trial demonstrated that pulsed electromagnetic field produced a trend in improving microcirculation, biomechanical properties of the wound tissue and wound healing status. As the sample size was small, a larger scale of clinical trial is needed to confirm that PEMF is an effective treatment for enhancing healing for diabetic foot ulcers.
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