Nipple necrosis after nipple-sparing mastectomy and immediate breast reconstruction is a troublesome complication and hard to predict intraoperatively. Indocyanine (ICG) angiography may provide perfusion clues. However, being affected by skin temperature or vasoconstrictors and inevitable dye use hinder its use in monitoring nipple necrosis. The thermal imaging camera indirectly reveals blood perfusion intuitively without dye injection. Thus, we evaluated its usefulness in monitoring nipple necrosis as an early predictor.
Nine nipple-necrosed patients out of 33 immediate breast reconstructions with prepectoral direct-to-implant or tissue expander insertion patients were enrolled (alpha 0.05, beta 0.8). Temperature differences between the nipple and surrounding skins (3 points in perpendicular except for the incision site) were measured using the thermal image of the breast postoperative day one (Thermal resolution: 0.07℃). Mann-Whitney test and a receiver operating characteristics (ROC) curve analysis were performed.
Patients with nipple necrosis showed a statistically significant temperature difference between the surrounding tissue and nipple than the non-necrosed patients (Mean -0.98℃ vs. -0.40℃, p=0.022). The ROC curve revealed an area under the curve (AUC) of 0.76 and an optimal cut-off value of -0.63℃ (Sensitivity 0.778, specificity 0.708).
On postoperative day one, the nipple necrosed group showed a significantly colder nipple temperature compared to the surrounding skin than the non-necrosed group, thus implying nipple ischemia. Although AUC showed acceptable reliability of the thermal imaging for predicting nipple necrosis, a more reliable classifier is needed. However, thermal imaging can be useful for postoperative monitoring as it can repetitively monitor nipple temperature noninvasively and intuitively.