The treatment of scar contracture has always been the difficult and key point in clinical research. As a new treatment method, fractional laser has a good effect on the early treatment of scar. After fractional laser thermal stimulation, the texture of scar improved and the traction symptom can be relieved to a certain extent. However, in practical application, the relationship between fractional laser parameters and the improvement degree of scar ductility is not clear, resulting in the blindness and randomness of the treatment. Finite element model analysis is a widely used numerical analysis method with high precision in organization simulation. In this paper, we will review and prospect application of fractional laser in the treatment of scar contracture combining with finite element model analysis method.

The treatment of scar contracture has always been the difficult and key point in clinical research. As a new treatment method, fractional laser has a good effect on the early treatment of scar. After fractional laser thermal stimulation, the texture of scar improved and the traction symptom can be relieved to a certain extent. However, in practical application, the relationship between fractional laser parameters and the improvement degree of scar ductility is not clear, resulting in the blindness and randomness of the treatment. Finite element model analysis is a widely used numerical analysis method with high precision in organization simulation. In this paper, we will review and prospect application of fractional laser in the treatment of scar contracture combining with finite element model analysis method.

Objective:To investigate the effect of tourniquet-reperfusion augmented infrared thermography(TRAIRT) on locating the dominant perforator to assist design of free medial sural artery perforator flap.Methods:The data of patients with skin soft tissue defect of upper limb repaired by free medial sural artery perforator flap in Department of Hand Surgery, Ningbo Sixth Hospital from May 2019 to January 2022 were retrospectively analyzed. Color Doppler ultrasonography (CDU) and TRAIRT were used to locate the dominant perforator auxiliary flap design before surgery and after anesthesia. In the TRAIRT video, the hot spot with "early emergence, high brightness and fast expansion" was selected as the advantageous perforator. During the operation, the flap was elevated and transferred to the affected area to cover the defect wound according to the designed mark points, and fixed by the absorbable sutures with an interrupted suturing method, then end-to-end vascular anastomosis was performed successively. The donor area was sutured directly or sutured with full thickness skin grafts depending on the area of the wound. The donor and recipient areas of the flap were observed and the patients’ satisfaction was recorded. The gold standard was the actual location of the perforating vessel found during the operation. Compared with the gold standard, the location of the perforating vessel explored by TRAIRT and CDU was considered to be accurate (positive) if the distance was less than 10 mm. The sensitivity (accurate number of perforators/actual number of perforators during operation ×100%) and positive predictive value (accurate number of perforators/total number of perforators×100%) of the two methods were calculated, expressed as %, and the sensitivity of the two methods was compared by paired χ2 test. Kappa coefficient was used to analyze the consistency of the two methods to detect perforating vessels. The perforator detection time of TRAIRT and CDU were recorded, expressed as Mean±SD, and statistically analyzed by paired sample t-test. Results:A total of 23 patients were included, consisting of 14 males and 9 females, agd 21-70 years old, average age of 43 years old. The wounds were on forearm in 5 cases, wrist in 2 cases, and hand in 16 cases. The wound area was 4.5 cm × 5.5 cm-6.5 cm × 12.0 cm. Intraoperative flap incision area was 5.0 cm × 6.0cm-7.0 cm × 13.0 cm. After operation, 22 cases of flaps survived, 1 case had superficial necrosis at the distal end, which healed after repeated dressing change. The donor area of flaps healed well, with primary suture in 20 cases and full thickness skin grafting in 3 cases. Postoperative follow-up was 5-16 months (mean 8.4 months). The flaps had no bulge, swelling and abrasion. The texture and color were similar to the medial calf skin, and the scars in the donor and recipient areas were not obvious. The patients were satisfied with the recovery. Among the 23 patients, 49 perforators were found by TRAIRT, 50 perforators were found by CDU, and 53 perforators were found intraoperatively. The sensitivity of TRAIRT and CDU was 88.7% (47/53) and 90.6% (48/53), with no significant differences ( P>0.05), and the positive prediction value was 95.9% (47/49) and 96.0% (48/50) respectively. The Kappa coefficient was 0.89, indicating a good consistency between the two methods. The time required for TRAIRT to detect perforators was significantly shorter than that of CDU, with statistical significance [(6.52±2.02) min vs. (17.87±2.49) min, P<0.01]. Conclusion:TRAIRT has a good consistency with CDU in detection of medial sural artery perforator. The application of TRAIRT in designing medial sural artery perforator flap for wound repair is good, and it has advantages of short time taking, simple operation, economy and non-invasiveness.

Objective:To investigate the effect of tourniquet-reperfusion augmented infrared thermography(TRAIRT) on locating the dominant perforator to assist design of free medial sural artery perforator flap.Methods:The data of patients with skin soft tissue defect of upper limb repaired by free medial sural artery perforator flap in Department of Hand Surgery, Ningbo Sixth Hospital from May 2019 to January 2022 were retrospectively analyzed. Color Doppler ultrasonography (CDU) and TRAIRT were used to locate the dominant perforator auxiliary flap design before surgery and after anesthesia. In the TRAIRT video, the hot spot with "early emergence, high brightness and fast expansion" was selected as the advantageous perforator. During the operation, the flap was elevated and transferred to the affected area to cover the defect wound according to the designed mark points, and fixed by the absorbable sutures with an interrupted suturing method, then end-to-end vascular anastomosis was performed successively. The donor area was sutured directly or sutured with full thickness skin grafts depending on the area of the wound. The donor and recipient areas of the flap were observed and the patients’ satisfaction was recorded. The gold standard was the actual location of the perforating vessel found during the operation. Compared with the gold standard, the location of the perforating vessel explored by TRAIRT and CDU was considered to be accurate (positive) if the distance was less than 10 mm. The sensitivity (accurate number of perforators/actual number of perforators during operation ×100%) and positive predictive value (accurate number of perforators/total number of perforators×100%) of the two methods were calculated, expressed as %, and the sensitivity of the two methods was compared by paired χ2 test. Kappa coefficient was used to analyze the consistency of the two methods to detect perforating vessels. The perforator detection time of TRAIRT and CDU were recorded, expressed as Mean±SD, and statistically analyzed by paired sample t-test. Results:A total of 23 patients were included, consisting of 14 males and 9 females, agd 21-70 years old, average age of 43 years old. The wounds were on forearm in 5 cases, wrist in 2 cases, and hand in 16 cases. The wound area was 4.5 cm × 5.5 cm-6.5 cm × 12.0 cm. Intraoperative flap incision area was 5.0 cm × 6.0cm-7.0 cm × 13.0 cm. After operation, 22 cases of flaps survived, 1 case had superficial necrosis at the distal end, which healed after repeated dressing change. The donor area of flaps healed well, with primary suture in 20 cases and full thickness skin grafting in 3 cases. Postoperative follow-up was 5-16 months (mean 8.4 months). The flaps had no bulge, swelling and abrasion. The texture and color were similar to the medial calf skin, and the scars in the donor and recipient areas were not obvious. The patients were satisfied with the recovery. Among the 23 patients, 49 perforators were found by TRAIRT, 50 perforators were found by CDU, and 53 perforators were found intraoperatively. The sensitivity of TRAIRT and CDU was 88.7% (47/53) and 90.6% (48/53), with no significant differences ( P>0.05), and the positive prediction value was 95.9% (47/49) and 96.0% (48/50) respectively. The Kappa coefficient was 0.89, indicating a good consistency between the two methods. The time required for TRAIRT to detect perforators was significantly shorter than that of CDU, with statistical significance [(6.52±2.02) min vs. (17.87±2.49) min, P<0.01]. Conclusion:TRAIRT has a good consistency with CDU in detection of medial sural artery perforator. The application of TRAIRT in designing medial sural artery perforator flap for wound repair is good, and it has advantages of short time taking, simple operation, economy and non-invasiveness.