Fitted Pressure Garment of Assessment of Scar Thickness on Third-Degree Burns through Ultrasonic Measurement

The aim of this study was to assess the thickness of the scars on the left arm of a female third-degree burn patient through ultrasonic examination in order to investigate the use of 25-mm Hg pressure garments, which are a key treatment for burns. The patient was injured with third-degree burns more than 10 years ago. Sixteen scars were examined. The resulting Pearson correlation of the forearm and upper arm was 0.138 (weak correlation; R2=0.0191). Therefore, in this case, all data points fell on a straight line with a positive (upward) slope. This result indicated different thicknesses for the upper arm and forearm third-degree burn scars; this result displays different thickness for the upper arms and forearm the third degree burn scars; the scars did not spread evenly due to the loading capacity of different parts of body instead of the pressure by pressure garment.


Introduction
All patients with burns over 20-25% (second degree) of the total body surface area (TBSA) develop systemic changes that influence their survival [1]. Asian skin is characterised by increased proliferation of fibroblast and more vigorous collagen formation, which results in prolonged erythema compared with Caucasian skin. Consequently, scars in most Asian patients require longer maturing [2,3]. Generally, wounds that do not heal within 2-3 weeks are considered most at risk for excessive scar formation [1,[4][5][6]. Asians are more likely to develop hypertrophic scars compared with Caucasians, and Africans are more likely to develop hypertrophic scars than Asians [5,7]. Hypertrophic scarring is very common among the Chinese population [8]. In general, hypertrophic scarring occurs more frequently in women and patients of younger age groups [9].
Scars can be emotionally devastating, leading to mental and emotional complications. Scars can be disfiguring and aesthetically unpleasant. The side effects of scarring may include severe itching, tenderness, pain, sleep disturbances, anxiety, depression, and disruption of daily activities [5]. Scarring is a natural part of the healing process after an injury. Scar appearance and treatment depends on multiple factors, including wound depth, size, and location and the age, sex, ethnicity, and genetics of the patient. Types of scars include hypertrophic scars (HSs) and keloid scars [10,11].
The basic principle in scar treatment is applying constant pressure to the scars to occlude the capillaries and restrict oxygen availability to the affected region [7,20,21]. Minimising HS formation by creating a hypoxic condition results in focal degeneration of the perivascular particle cells and improves patients' range of movement [7,[20][21][22].
The nature of scarring appears to depend on factors such as race, age, genetic predisposition, hormone levels, atopy, patient immunologic responses, type of injury, wound size and depth, anatomic region affected, and mechanical tension on the wound [14].
Scars must be moisturised once or twice a day with mild moisturiser and massage to soften the scars. Scars should be massaged firmly to help disband the bundles of collagen within the scar. Massaging and applying skin creams can reduce any itching caused by the maturing scars [16,[23][24][25]28,29]. Without the constant pressure of the garment, the collagen fibres of the scar tissue grow unsystematically, whereas the inner structure of a scar matured under constant pressure more closely resembles the natural patterns of fibres in healthy skin [20][21][22]26,31].
Burn scars are probably the scars with the highest impact on quality of life [17]. Both physical and psychological effects related to excessive scarring may hamper quality of life, including the often lengthy, painful treatment, which often provides only a suboptimal result [18,32]. Generally, a period where the pressure garment is worn for at least 6-18 months is required for burn scar maturation, at which time the redness (erythema) of the scar subsides, the scar no longer appears inflamed, and the scar contracture diminishes [15].
The following laboratory based on the patient's medical records and current status of the experiment.

Pressure garments
The pressure of the pressure garment was 25 mmHg made by the same pressure garment's manufacturer and tailors with the same materials as well as confirmed using the same pressure gauge which conditions are the same as the original pressure garment the patient wore in treatment. The pressure garment's was checked on a monthly basis to ensure consistent pressure.

Ultrasound scans
Noninvasive skin thickness measurement has been proposed and used clinically with varying degrees of success. This technique is useful not only for objective assessment but also for comparing two or more treatment techniques [7,22,33,34].
In this study, ultrasound measurements were conducted by an experienced medical Doctor who was trained to use this device by radiologists; ultrasound equipment (Philips HD15 Sonic CT) was used to measure the thickness of normal skin and scars.

Patient and type of scars
The patient in the present study (age: 31 years old, sex: female, duration wearing pressure garment: 10 years) suffered second-to-thirddegree burns to 77% of her TBSA and a level-1 inhalation injury;who started wearing pressure garment on the 92 nd day of being injured. We examined the left arm and hand, which had third-degree burn injuries.

Procedure
Research data collection: Half an hour before scanning, the patient's pressure garments were removed. First, we used a marker to highlight the location of the scar from the upper arm to forearm (randomly) (Figures 1 and 2). Sufficient ultrasound gel was applied to mark a location between the ultrasound gel and the surface of the skin (Figure 2). The patient had 16 burn scars measured from the upper arm to outside elbow: deltoid to acromion 5 cm; distal to acromion scar

Results
The patient's 16 scars were measured on 23 August 2013 and 27 December 2014 (Figures 2-4); they were all significantly thicker than normal skin. The mean thicknesses of these 16 scars from the upper arm and forearm were 0.544 cm and 0.609 cm, respectively ( Table 2). We determined that the thickness of normal skin was 0.15 cm through an ultrasound scan in 2013 (Figures 2 and 3). The result was a Pearson correlation of forearm and upper arm of 0.138. It indicated a weak correlation with R 2 =0.0191. Therefore, in the case, all the data fell on a straight line with a positive (upward) slope (Table 1 and Figure.1).
We determined that the statistical distribution of forearm burn scars was approximately 1.8 times (Table 2) greater than that of upperarm burn scars; the difference between the standard deviation of the forearm and the upper arm and its mean forearm scarring value was considerable, but the upper-arm burn scars' height was within the limits of third-degree burns ( Table 2, Figures 5 and 6).
Moreover, the interquartile ranges (IQR) of the upper arm and forearm were 0.220 cm and 0.406 cm, respectively ( Figures 5, 6 and Table 3). The ranges for forearm scar thickness were almost twice those for upper-arm scar thickness; the median difference for both was 8.4% (Table 3): upper arm and forearm scar thicknesses were 0.5235 cm and 0.5715 cm, respectively. The upper-arm and forearm scar thickness IRQ had a difference of approximately 54%. The data were used to roughly estimate the degree of dispersion ( Figure 5).
To sum up, upper arm was approximately 3.49 times and forearm was 3.81 times higher than the scar thickness for the normal skin which thickness was about 0.15 cm, respectively (Table 4).

Discussion
This study validated the hypothesis that 25 mmHg is not the optimal pressure for female patients with third-degree burns on the left arm. According to previous statistical result, two factors are considered to reduce the function of 25 mmHg pressure garment for female patients with third-degree burns on the left arm, namely, the same pressure has different results on different body parts and errors of tailored measurement. Due to the previous discussion, we can confirm that burns at the same depth but on different body parts differ in scar thickness. This explain why some patients require silicone gel sheeting, massage, steroids, or presurgical skin graft, so minimal scarring results because identical pressure on different body parts has different results.  Therefore, the results of the paper suggest that burn scars should have appropriate pressure applied on the basis of the medium scar height to avoid an increase in the size of scars and to stabilise burns. Furthermore, many experts point out a fact that placing the human body in different postures affects the measurement results because of the difference of a cross-section and a straight section [35,36]. In skin surface contractility and extensibility during body movements, each point has a different maximum pull. This is particularly true of the hands, upper arms, elbows, and forearms; tension on these body parts The result was a Pearson correlation of forearm and upper arm was 0.138. It indicated that there was a weak correlated with R 2 =0.0191.Therefore, in the case, all of data fell on straight line with positive (upward) slope. The mean of prominent scars of these 16 scars from upper arm was 0.544 cm and forearm was 0.609cm We found that the statistical distribution of forearm burn scars was approximately1.8 times.    was particularly severe [36,37]. The same pressure (25 mmHg) applied to the upper-arm and forearm scars produced a considerable disparity. Therefore, this pressure was not the most suitable.
Although some experts have suggested applying pressure within a range of 15 mm Hg-25 mmHg [16,23,24,26,29,30,[38][39][40], many experts have recommended wearing silica gel film inside the pressure garments (only at locations with hard or convex scars), but this type of silicon film can only be worn for 8-12 hours per day [6,12,14,41,42] because such items can lengthen scarring duration and can be allergenic. However, they still have a favourable effect.
This study investigated the ultrasound-measured thickness of 16 burn scars for a decade-old scar and analysed the association of thicknesses of these scar with the initial burn depth ascertained through ultrasound scan.
According to many studies, 25 mmHg is the optimal pressure for postburn pressure garments; however, these studies include only healthy human experiments and human machine model experiments [16,23,24,29,30].
In this study, the patient wore pressure garments of 25 mmHg from day 92 posttreatment (the patient did not leave the intensive care unit until day 86 posttreatment and was discharged with burns covering 9% TBSA). After 10 years, the median number of forearm scars was greater than the median number of upper-arm scars by 8% (Left arm: thirddegree burns, MEEK split-thickness skin graft: 1:9, donor site: scalp.). The same pressure of 25mmHg was applied to the left-arm scars; upper-arm and forearm scar thicknesses were 0.5235 ± 0.128 cm and 0.609 ± 0.230 cm, respectively). However, the result mentioned above was weakly correlated.  Using the quartile calculation of third-degree burns, upper arm and forearm scars of the full range, the IQRange of upper arm is 0.220 cm, and the forearm is 0.406 cm. Table 4: Scar thickness comparison Table.