Low-Temperature Burn on Replanted Fingers and Free Flaps in Hand

BACKGROUNDPatients who have undergone microsurgery for reconstruction with a free flap or finger replantation are vulnerable to heat injury. Moreover, some of these injuries can occur at low temperatures. Although the temperature does not reach the threshold to cause burns in the adjacent normal tissues, burns can occur in the areas that underwent microsurgery. On the other hand, this type of burn is not completely understood and there are few reports of the clinical prognosis. METHODSThe medical records of patients who received warm therapy using an infrared heat lamp with the appropriate temperature after hand surgery from January 2009 to December 2016 were reviewed. The patients were classified into 2 groups. Group A comprised patients who underwent free flap or replantation surgery of the hand. Group B comprised patients who underwent other hand surgeries without microsurgery, such as tenorrhaphy, tenolysis, or joint surgery. Through the medical records, all patients with second- or third-degree thermal burns were selected. The relationship between the 2 types of surgery and thermal injury and the timing of the burn after microsurgery were analyzed. RESULTSGroups A and B were composed of 370 (mean age, 48.2 years) and 7010 patients (mean age, 44.5 years), respectively. Burns requiring treatment occurred in 4 patients in group A and in 1 patient in group B. The proportion of low-temperature burns was 4 of 370 in group A and 1 of 7010 in group B. The occurrence of low-temperature burns was more associated with patients who had undergone microsurgery for a hand reconstruction with free flap or finger replantation (P < 0.05). In the patients who underwent microsurgery, all 4 patients had thermal burns within 1 year after surgery. CONCLUSIONSLow-temperature thermal burns can occur in patients who have undergone microsurgery for a hand reconstruction. This is believed to be related to a disruption of the thermoregulatory function of the skin and poor nerve regeneration, as well as more heat accumulation in the surgical area after microsurgery.