[Effects of three-dimensional computed tomography angiography-assisted free medial sural artery perforator flap in repairing foot wounds].

Objective: To investigate the effects of three-dimensional computed tomography angiography (3D-CTA)-assisted free medial sural artery perforator flap in repairing foot wounds. Methods: A retrospective observational study was conducted. From May 2018 to August 2021, 18 patients with foot soft tissue defects who met the inclusion criteria were admitted to the Department of Spine and Trauma Orthopedics of the Yidu Central Hospital of Weifang, including 13 males and 5 females, aged 19 to 55 years, with a wound area of 4.0 cm×3.0 cm-9.0 cm×8.0 cm at admission. Before the operation, CT scanner was used to scan the area from the supracondylar femur to the middle segment of the fibula of patients, and the obtained data were extracted into the Mimics16.0 software and analyzed to determine the pre-selected perforator, and then the image data of the pre-selected perforator side were analyzed further, and the body surface projection position of the perforating point of the medial sural artery in the calf region was marked. Based on the above examination, the flap was designed and cut according to the shape and area of the patient's foot tissue defect, and the area of flaps ranged from 5.0 cm×4.0 cm to 10.0 cm×9.0 cm. The donor sites were sutured directly or covered by skin grafting. The type of perforator, the diameters of perforator at the beginning and outlet point, and the location of the outlet point of perforator of the medial sural artery were observed under 3D-CTA examination before operation and compared to see if they were consistent with the observation under intraoperative condition. The survival of the flaps after operation was recorded. During follow-up, the satisfaction of patients with the wound repair effects, the sensory recovery of the recipient flaps, the healing of the donor wound, and whether there were complications affecting limb functions were recorded. Data were statistically analyzed with Kappa consistency test and equivalence test, and the 95% confidence intervals of measurement difference of perforator diameter and outlet point position of perforator were -0.50-0.50 mm and -2.0-2.0 cm, respectively. Results: The types of medial sural artery perforators observed during operation were type Ⅰ in 3 cases, type ⅡA in 6 cases, type ⅡB in 8 cases, and type Ⅲ in 1 case, which was consistent with the results of 3D-CTA before operation (Kappa=1.00, P<0.05). The blood vessel diameter detected by 3D-CTA before operation at the beginning of perforator of medial sural artery was (1.81±0.39) mm, and the blood vessel diameter at the outlet point of the perforator was (0.83±0.21) mm, which were close to the actual intraoperative measurement of (1.83±0.43) and (0.86±0.22) mm, respectively; equivalence test showed that the 95% confidence intervals of the measurement differences of diameter of medial sural artery perforator at beginning and outlet point were -0.18-0.22 and -0.08-0.14 mm, respectively, with both P values <0.05. The preoperative 3D-CTA detected that the perforating position at the deep fascia of the perforator of the medial sural artery, namely the vertical distance with the popliteal fold was (12.2±1.4) cm, and the horizontal distance with the posterior midline was (2.6±0.7) cm, which were respectively close to the actual intraoperative measurement of (12.4±1.4) and (2.6±0.7) cm; equivalence test showed that the 95% confidence intervals of the measurement differences in the vertical distance with the popliteal fold and the horizontal distance with the posterior midline of the outlet point of medial sural artery perforator were -1.06-1.26 and -0.46-0.66 cm, respectively, with both P values <0.05. After surgery, all flaps of 18 patients survived without vascular crisis. After 1 year of follow-up, the satisfaction degree of 16 patients was excellent and 2 patients was good with the wound repair effects, with a satisfaction ratio of 16/18; the sensory recovery of flap was evaluated as S3 in 11 cases and S2 in 7 cases; the donor wounds healed well without obvious scar or contracture, with no effect on limb joint functions. Conclusions: The medial sural artery perforator flap achieved good results in repairing foot wound with high degree of patient satisfaction. Preoperative application of 3D-CTA can realize the standardization, systematization, and visualization of artery perforator flap.