[Infrared thermography-assisted design and harvesting of ultrathin anterolateral thigh perforator flaps].

Objective: To explore the application value of infrared thermography in the design and harvesting of ultrathin anterolateral thigh perforator flaps.

Methods: Between June 2024 and December 2024, 9 cases of ultrathin anterolateral thigh perforator flaps were designed and harvested with the assistance of infrared thermography. There were 7 males and 2 females, aged 21-61 years (mean, 39.8 years). The body mass index ranged from 19.49 to 26.45 kg/m² (mean, 23.85 kg/m²). Causes of injury included 5 cases of traffic accident injuries and 4 cases of machine crush injuries. There were 3 cases of leg wounds, 2 cases of foot wounds, and 4 cases of hand wounds. After debridement, the size of wound ranged from 7 cm×4 cm to 13 cm×11 cm. The time from admission to flap repair surgery was 5-12 days (mean, 7 days). Preoperatively, perforator localization was performed using a traditional Doppler flow detector and infrared thermography, respectively. The results were compared with the actual intraoperative locations; a discrepancy ≤10 mm was considered as consistent localization (positive), and the positive predictive value was calculated. All 9 cases were repaired with ultrathin anterolateral thigh perforator flaps designed and harvested based on thermographic images. The size of flap ranged from 8 cm×5 cm to 14 cm×8 cm, with a thickness of 3-6 mm (mean, 5.2 mm). One donor site was repaired with a full-thickness skin graft, and the others were sutured directly. Postoperatively, anti-inflammatory, anticoagulant, and anti-vascular spasm treatments were administered, and follow-up was conducted.

Results: The Doppler flow detector identified 22 perforating vessels within the set range, among which 16 were confirmed as superficial fascia layer perforators intraoperatively, with a positive predictive value of 72.7%. The infrared thermograph detected 23 superficial fascia layer perforating vessels, and 21 were verified intraoperatively, with a positive predictive value of 91.3%. There was no significant difference between the two methods [OR (95%CI)=3.93 (0.70, 22.15), P=0.100]. The perforator localization time of the infrared thermograph was (5.1±1.3) minutes, which was significantly shorter than that of the Doppler flow detector [(10.1±2.6) minutes; MD (95%CI)=-5.00 (-7.08, -2.91), P<0.001]. Postoperatively, 1 case of distal flap necrosis healed after dressing change; all other flaps survived successfully. The skin grafts at donor site survived, and all incisions healed by first intention. All patients were followed up 3-6 months (mean, 4.7 months). No pain or other discomfort occurred at the donor or recipient sites. All patients with foot wounds could walk with shoes, and no secondary flap revision was required. Flaps in 3 hand wound cases, 2 foot wound cases, and 3 leg wound cases recovered light touch and pressure sensation, but not pain or temperature sensation; the remaining 2 cases had no sensory recovery.

Conclusion: Preoperative localization using infrared thermography for repairing ultrathin anterolateral thigh perforator flaps can help evaluate the blood supply status of perforators, reduce complications, and improve surgical safety and flap survival rate.