Does the advantage of transcutaneous oximetry measurements in diabetic foot ulcer apply equally to free flap reconstruction?

[BACKGROUND] Transcutaneous oxygen pressure (TcpO) is a precise method for determining oxygen perfusion in wounded tissues. The device uses either electrochemical or optical sensors.

[AIM] To evaluate the usefulness of TcpO measurements on free flaps (FFs) in diabetic foot ulcers (DFUs).

[METHODS] TcpO was measured in 17 patients with DFUs who underwent anterolateral thigh (ALT)-FF surgery and compared with 30 patients with DFU without FF surgery.

[RESULTS] Significant differences were observed in the ankle-brachial index; duration of diabetes; and haemoglobin, creatinine, and C-reactive protein levels between the two groups. TcpO values were similar between two groups except on postoperative days 30 and 60 when the values in the ALT-FF group remained < 30 mmHg and did not increase > 50 mmHg.

[CONCLUSION] Even if the flap is clinically stable, sympathectomy due to adventitia stripping during anastomosis and arteriovenous shunt progression due to diabetic polyneuropathy could lead to low TcpO values in the ALT-FF owing to its thick fat tissues, which is supported by the slow recovery of the sympathetic tone following FF. Therefore, TcpO measurements in patients with DFU who underwent FF reconstruction may be less accurate than in those who did not.