Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/85062
Title: Development of pressure therapy gloves for hypertrophic scar treatment
Authors: Yu, Annie
Degree: Ph.D.
Issue Date: 2015
Abstract: Pressure garments are commonly used in the treatment of hypertrophic and deformed scars. These garments need to be continuously worn so that adequate pressure can be applied to the hypertrophic scar, so as to flatten the scar and prevent contracture. Thus, pressure monitoring, patient compliance and comfort sensation are crucial in pressure garment therapy. Based on the body dimensions of patients, pattern pieces are developed in a reduced size so as to exert pressure onto specific parts of the recipients of garment pressure therapy. The amount of reduction is called the reduction factor (RF). Due to the lack of actual garment/scar interfacial pressure measurement in hospitals, the amount of pressure exerted by current therapy garments and fabrics can only be subjectively assessed based on the experience of individual practitioners. The patient compliance rate of the continuous use of pressure gloves is another concern. Most of the complaints with regards to pressure garments are related to wear comfort, which include barriers to mobility, sweating, itching, pain and poor fit. These problems are especially substantial with respect to pressure therapy gloves as the hand is most often used in the performing of daily activities and sensitive to different sensations. The aim of this research project is to improve the quality of treatment for hypertrophic scars on the hand by increasing the wear comfort of pressure therapy gloves and facilitating understanding of the pressure delivery of the glove. First, there will be a review of current custom-made pressure therapy gloves and clinical situations through an 18-week study on 5 patients with hypertrophic scars on their hands. This will help to identify the possible direction for improving treatment outcomes. The measuring of hand anthropometric data for the development of optimal fitting gloves is crucial. In pursuing greater accuracy in hand anthropometric measurements, the scanning of hand surfaces with the aid of an image analysis system to acquire measurements is an alternative to manual means. A new hand measuring approach that uses 2D and 3D scanning has been proposed and evaluated through comparisons with manual measurements. It is found that hand data taken from 3D image analysis have no significant differences compared with the manual measurements made on the hand and wrist circumferences, length and breadth. To understand the pressure given by pressure gloves made of different materials and RFs, the tensile properties and tension decay after the extension of seven types of fabrics which determined their pressure delivery ability are examined. Based on the fabric tensile behaviour, the corresponding glove pressure is predicted by the local strain, fabric tension per unit length and curvature of the hand surface. No statistical difference is found between the predicted glove pressures and the measured values. It is also revealed that the pressure measurement positions and their corresponding curvature and geometry changes caused by hand movements and postures are closely associated with the interfacial pressure delivered by the glove. The physiological and psychophysical effects of pressure therapy gloves on human responses have been investigated. The heart rate (HR), blood pressure (BP), glove-skin microclimate, hand performance, forearm muscle activity, grip strength and psychophysical responses when wearing pressure gloves made of various fabric types and with different RFs are studied through a series of wear trials with 10 subjects who do not have hypertrophic scars. The results indicate that the impacts of the different gloves on the HR and BP are not significant. However, the pressure gloves show a noticeable influence on the skin-glove microclimate. Fabric properties which include air permeability, moisture retention and drying rate are identified as the main factors that affect the skin-glove temperature. Both the fabric type and RF of the pressure gloves have no significant effects on the tactile sensitivity of the fingertips. Nevertheless, the active range of finger motion, dexterity of the fingers in carrying out daily tasks and maximum gripping force are negatively affected. The adoption of a high RF of 20% in the glove pattern can negatively impact hand functions. The forearm muscle activity, which is measured by using surface electromyography (SEMG), is affected by the tightness of the glove. Besides that, the glove with a tighter pressure (RF of 20%) contributes to less perceived comfort and ease of hand motion.
In this study, it is also found that the current glove making process fails to provide patterns that properly fit the hand geometry, thus leading to inadequate pressure exerted onto the scar region, particularly in the finger web area. A new approach that considers the web spaces between fingers in the pattern development process of glove production is introduced. The angle of the finger web slants of 79 individuals are measured and evaluated by using a 3D scanning and image analysis method. Glove prototypes with modifications on the web spaces between fingers are produced and assessed through a wear trial with 10 subjects. The results show that gloves made with 45{493} finger web slants can effectively improve glove fit, comfort and ease of hand motion. Insert materials made of thermoplastic (e.g. Plastazote{170}) are often placed underneath pressure garments to increase the local pressure for effective scar treatment. However, the currently used insert material, Plastazote{170}, is barely breathable and quite uncomfortable. Therefore, spacer fabric is proposed as a potential insert material. The physical properties, compression behaviour and pressure delivery ability of five types of spacer fabrics are evaluated. The results show that the spacer fabrics are not only able to provide much lower air resistance (0.05-0.12 kPa s/m) and higher water vapour transmission rates (WVTRs; 34.35-102.39 g/h{168}m2) than Plastazote{170}, but also produce an interfacial pressure that is comparable to Plastazote{170} at various locations on the hand dorsum. A 24 week clinical study in which spacer fabric inserts are used in pressure gloves and applied to four hands with hypertrophic scarred skin also support that the spacer fabric insert is effective in scar treatment by providing good comfort and breathability, and hence pressure treatment acceptance and compliance are increased. With a full picture of the pressure amount given by a pressure glove, practitioners can more easily prescribe suitable pressure treatment. By using the finite element method (FEM), a biomechanical simulation model that simulates the skin pressure in relation to the contours of the human hand and fabric properties of the pressure therapy glove has been developed. The simulation model can show a trend of pressure distribution with good accuracy. As shown above, the research results provide useful information for the selection of suitable materials and RFs for pressure glove therapy. Feasible solutions to improve the glove fit and comfort of pressure therapy are suggested. The simulation model used to predict the pressure distribution over the hand dorsum can also enhance the effectiveness and treatment quality of pressure glove therapy. The output of this project can extend to the development of other pressure garments and will advance our knowledge on a new dimension of medical clothing for hospital patients.
Subjects: Pressure suits -- Therapeutic use.
Hypertrophic scars -- Care.
Hong Kong Polytechnic University -- Dissertations
Pages: xxvi, 239 pages : illustrations
Appears in Collections:Thesis

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