| Background:The treatment of deep partial-thickness burns is crucial and difficult in the department of burns.Conservative treatment requires multiple dressings which may make patients suffered more pain and increase the risk of wound infection.Reluctant concrescence can increase the incidence of the formation of scar which will influence the appearance and physiological function of skin.Dermabrasion is a novel therapy which can effectively remove necrotic tissue without removing viable tissue and promote wound healing.As the depth of dermis are variable,the depth of deep partial-thickness burns vias from superficial burn to third-degree burn.Recent studies have shown that the accurate diagnosis rate of partial-thickness burns which were not healed within three weeks is only 50%-60%.It is a great challenge for surgeons of whether perform dermabrasion as excessive dermabrasion will increase the difficulty of surgeryand decrease the success rate.Moreover,necrotic tissue can not be removed completely.Many auxiliary diagnostic apparatus have been used as reported in literatures such as ultrasonography,laser speckle imaging,digital thermal imaging,ultrasound elastography,laser doppler flowmetry and tissue spectrophotometry,active dynamic thermography.However,these instruments have not been widely used in clinical at present.During the 1970s,ultrasound was widely used in medicine.The study by Goans on animals demonstrated that ultrasound could be used as a quantitative method of assessment of burn wounds.The research was to evaluate the interface between the coagulation necrosis layer and the remaining viable dermis which could also detect the interface between the deep dermis and the subcutaneous fat.Thus,giving a measurement of the remaining dermis.According to this study,Kalus and colleagues used a 5-MHz probe in two patients concern healing time and the need for excision.As a noninvasive,expedient way,ultrasound can help determine the diagnosis of burn depth in animal models.With the advancements of technology,improved images in animal models as probes went to 10 MHz and 18.5 MHz and in humans for the assessment of other skin conditions such as melanoma and psoriasis.Ultrasonography with frequency>15 MHz has been utilized in patients with dermatological diseases to identify cutaneous and adnexal layers and structures.Ultrasonography with frequency>20 MHz has a better resolution which is suitable for the detection of superficial tissue.Clinical observation is the most common method for evaluating the severity of burns at present.Pathology is golden standard in the evaluation of the depth of burns.But this method has some limitations:traumatic and time-consuming which will delay the optimal opportunity of surgery.High-frequency ultrasonography can provide an objective imaging evidence to judge the feasible of dermabrasion in a non-invasive and time-saving manner.Objective:To investigate the application of high-frequency ultrasonography in dermabrasion of patients with deep partial-thickness burns and the changes of skin tissue structure,blood flow signals and its relationship with healing time before and after treatment of dermabrasion.Providing the objective basis of imaging for dermabrasion in clinical application.Methods:Twenty-six patients with deep partial-thickness burns conforming to the study criteria were hospitalized in our unit from March 2015 to March 2016.Patients were all performed with dermabrasion.The structure of skin tissue and blood flow signals of uninjured side and wounds before dermabrasion,and those of wounds immediately post dermabrasion and on post dermabrasion day(PDD)1,3,5,7,10,14,and 21 were detected with high-frequency ultrasound,and the percentage of blood flow signals was calculated.According to the results of comparison between percentage of blood flow signals of wounds and that of normal skin before dermabrasion,patients were divided into no significant decrease group(NSD,n =19)and significant decrease group(SD,n=7).Wound healing time of patients in two groups was recorded.Data were processed with analysis of variance of repeated measurement,LSD test,t test and Chi-square test.The correlation between the percentage of blood flow signals of wounds before dermabrasion and wound healing time of 26 patients were analyzed by Spearman correlation analysis.Results:(1)Epidermis of normal skin of patients in two groups before dermabrasion showed continuous smooth linear hyperecho,which was stronger than that of dermis,and boundary of dermis and subcutaneous tissue showed stronger discontinuous linear echo than that of dermis,which gradually transited to subcutaneous tissue.In group NSD,epidermis of wound of patients before dermabrasion showed intermittent rough linear echo,which was weaker than that of normal skin epidermis,and there was no obvious abnormity of boundary between dermis and subcutaneous tissue.Immediately post dermabrasion and on PDD1,no linear hyperecho of epidermis was observed,showing complete attrition of epidermis,and the echo of dermis and subcutaneous tissue had no obvious change as compared with that before dermabrasion,with flat surface of dermis and partly abraded superficial-dermis but relatively well preserved dermis tissue in whole.The epidermis showed discontinuous linear hyperecho,and epidermis was discontinuously regenerated on PDD 3 and 5,Partial continuous linear hyperecho was detected in the epidermis,showing partial continuous regeneration of epidermis on PDD 7 and 10.The regenerated epidermis was thicker than normal skin epidermis and showed rough linear hyperecho with non-uniform thickness on PDD 14.The regenerated epidermis was thicker than normal skin epidermis and showed rather smooth linear hyperecho with uniform thickness on PDD 21.In group SD,the structure of epidermis and dermis of wounds of patients before dermabrasion,immediately post dermabrasion,and on PDD1 was similar to that in group NSD,but the echo of boundary of dermis and subcutaneous tissue was weakened in different degrees.There was no linear hyperecho of epidermis,showing no epidermis was regenerated on PDD 3 and 5.Intermittent regeneration of epidermis appeared on PDD 7 and 10 with intermittent linear hyperecho.Partial continuous linear hyperecho was detected in the epidermis,showing partial continuous regeneration of epidermis on PDD 14 and 21.(2)The percentages of blood flow signals of wounds of patients in group NSD before dermabrasion,immediately post dermabrasion,and on PDD 1 were(3.1±1.3)%,(6.5±2.0)%,and(5.3±1.9)%respectively,higher than those in group SD[(0.9±1.1)%,(3.5±1.3)%,and(3.6±0.9)%respectively,P<0.05 or P<0.01].The percentages of blood flow signals of wounds of patients in two groups were similar at the other time points(with P values above 0.05).Compared with the percentage of normal skin in the same group[(3.2±0.7)%],the percentages of blood flow signals of wounds of patients in group NSD were significantly increased immediately post dermabrasion and on PDD 1(with P values below 0.01)but had no significant change at the other time points(with P values above 0.05).The percentages of blood flow signals of wounds of patients before dermabrasion in group SD was close to that of normal skin in the same group at each time point post dermabrasion(with P values above 0.05).(3)The wound healing time of patients in group NSD was(16.2±2.5)d,lower than that in group SD[(30.9±2.9)d,t =12.67,P<0.01].There was obvious negative correlation between the percent-age of blood flow signals of wounds before dermabrasion and wound healing time of 26 patients(r =-0.77,P<0.01).Conclusion:High-frequency ultrasound is a good way to observe the imaging features of wounds in patients with deep partial-thickness burns before and after dermabrasion,and it can provide objective imaging evidence for the performance of dermabrasion in patients with deep partial-thickness burns. |
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