Projected augmented reality in DIEP flap breast reconstruction: Projecting perforators on the skin using dynamic infrared thermography.

BACKGROUND: Dynamic infrared thermography (DIRT) is a quick and non-invasive technique for perforator mapping in free flaps that provides real-time information. After a cold challenge, areas best supplied with blood become visible hotspots on color-coded maps, indicating perforators. This study presents a proof of principle for a new and innovative feature of DIRT, where projected augmented reality is used to directly display thermal images on the patient's abdomen prior to the deep inferior epigastric artery perforator (DIEP) flap breast reconstruction. METHODS: A self-aligning projection device prototype (Anatomy Projector) equipped with an integrated thermal camera was used to obtain thermal information and project the color-coded map directly on the patient's abdomen before DIEP flap breast reconstruction. Projected DIRT hotspots were verified using a hand-held Doppler, and compared to the vascularity on computed tomography angiography (CTA), and intraoperative perforator measurements following a Cartesian grid. RESULTS: A total of 514 DIRT hotspots were projected in 50 patients, among them 97.3% could be verified using Doppler. The positive predictive value for CTA was 74.5%. Intraoperative measurements yielded 132 perforators in 71 flaps, among them 75 perforators (56.8%) correlated with projected DIRT hotspots, and half of them (54.7%) appeared within the first 5 emerging hotspots. CONCLUSION: This study showed that real-time display of thermal data in DIEP flap breast reconstruction is feasible via projected augmented reality. Projection facilitates convenient marking of hotspots, and a high resemblance to Doppler and CTA data was observed. Further research should assess the added value of projecting thermal images intraoperatively and in other fields of plastic surgery.

Perioperative hyperbaric oxygen treatment and postoperative complications following secondary breast reconstruction after radiotherapy: a case-control study of 45 patients.

INTRODUCTION: Radiotherapy reduces the risk of locoregional recurrence of breast cancer. As a side-effect, tissue can become hypocellular, hypovascular, and hypoxic and late radiation tissue injury can develop months or years later. Radiotherapy increases the risk of complications following secondary breast reconstruction. Hyperbaric oxygen treatment (HBOT) improves oxygenation of irradiated tissue and induces neovascularisation. This study evaluated whether the incidence of complications following secondary breast reconstruction after radiotherapy is decreased with perioperative HBOT. METHODS: In this retrospective case-control chart review study, patients who underwent perioperative HBOT (n = 15) were compared to lifestyle-matched (n = 15) and radiation damage-matched (n = 15) patients who underwent secondary breast reconstruction without HBOT. RESULTS: The HBOT group had significantly more severe radiation damage of the breast than the lifestyle- and radiation-damage-matched control groups (scoring grade 1-4, mean 3.55 versus 1.75 and 2.89 respectively, P = 0.001). Patients underwent on average 33 sessions of HBOT (18 sessions preoperatively and 15 sessions postoperatively). There was no significant difference in the incidence of postoperative complications between the HBOT group, lifestyle-matched group and radiation damage-matched group. Logistic regression analysis showed a lower risk of postoperative complications in patients who underwent HBOT. CONCLUSIONS: Although the HBOT group had more radiation damage than the control groups, the incidence of postoperative complications was not significantly different. This implied a beneficial effect of HBOT, which was supported by the logistic regression analysis. Definitive conclusions cannot be drawn due to the small sample size. Future research is justified, preferably a large randomised controlled trial.