Evaluation of dynamic infrared thermography as an alternative to CT angiography for perforator mapping in breast reconstruction: a clinical study.
ABSTRACT: The current gold standard for preoperative perforator mapping in breast reconstruction with a DIEP flap is CT angiography (CTA). Dynamic infrared thermography (DIRT) is an imaging method that does not require ionizing radiation or contrast injection. We evaluated if DIRT could be an alternative to CTA in perforator mapping.Twenty-five patients scheduled for secondary breast reconstruction with a DIEP flap were included. Preoperatively, the lower abdomen was examined with hand-held Doppler, DIRT and CTA. Arterial Doppler sound locations were marked on the skin. DIRT examination involved rewarming of the abdominal skin after a mild cold challenge. The locations of hot spots on DIRT were compared with the arterial Doppler sound locations. The rate and pattern of rewarming of the hot spots were analyzed. Multiplanar CT reconstructions were used to see if hot spots were related to perforators on CTA. All flaps were based on the perforator selected with DIRT and the surgical outcome was analyzed.First appearing hot spots were always associated with arterial Doppler sounds and clearly visible perforators on CTA. The hot spots on DIRT images were always slightly laterally located in relation to the exit points of the associated perforators through the rectus abdominis fascia on CTA. Some periumbilical perforators were not associated with hot spots and showed communication with the superficial inferior epigastric vein on CTA. The selected perforators adequately perfused all flaps.This study confirms that perforators selected with DIRT have arterial Doppler sound, are clearly visible on CTA and provide adequate perfusion for DIEP breast reconstruction.Retrospectively registered at ClinicalTrials.gov with identifier NCT02806518 .
Project description:There are no in vivo studies that evaluate the effect of perforator dissection on the perfusion territory of a perforator (perforasome). In this study, indocyanine green fluorescence angiography (ICG-FA) and infrared thermography (IRT) were used intraoperatively to evaluate perforasome perfusion in hemi-DIEP flaps.<h4>Methods</h4>Patients selected for DIEP breast reconstruction were prospectively included in the study. Preoperative perforator mapping was performed with CTA and handheld Doppler ultrasound. In general anesthesia, perforasome perfusion was evaluated with ICG-FA and IRT both before surgery and after flap dissection with preserved dominant perforators.<h4>Results</h4>Thirty hemi-DIEP flaps were dissected in 15 patients (average BMI 26.6 kg/m<sup>2</sup>), of which 40% had been operated on in the lower abdomen. Fluorescence spots from ICG were associated with infrared radiation hotspots on IRT and these corresponded with the locations of the selected perforators. IRT and ICG-FA demonstrated similar patterns in perforasome perfusion before and after perforator dissection. Perforator dissection changed the perforasome perfusion. IRT made it possible to continuously monitor the perforator activity during surgery. ICG-FA easily identified areas with impaired flap perfusion due to previous surgery.<h4>Conclusions</h4>Perforasome perfusion is a dynamic process that changes with perforator dissection. ICG-FA and IRT are reproducible techniques for in vivo evaluation of perforasome perfusion and produce comparable results.
Project description:<h4>Background</h4>The maximum weight of tissue that a single perforator can perfuse remains an important question in reconstructive microsurgery. An empirically based equation, known as the flap viability index (FVI), has been established to determine what weight of tissue will survive on one or more perforators. The equation is FVI = Sum d(n)^4/W, where d is the internal diameter of each perforator and W is the final weight of the flap. It has been shown that if FVI exceeds 10, total flap survival is likely, but if under 10, partial flap necrosis is probable. The aim of this study was to measure absolute flow rates in deep inferior epigastric perforator (DIEP) flap pedicles and assess correlation with the determinants of the FVI, perforator diameter and flap weight.<h4>Methods</h4>Color Doppler ultrasound was used to quantify arterial flow in 10 consecutive DIEP flap pedicles 24 hours after anastomosis.<h4>Results</h4>In single-perforator DIEP flaps, flow rate was highly correlated with perforator diameter (r = 0.82, P = 0.01). Mean arterial flow rate was significantly reduced in DIEP flaps with 2 or more perforators (6 vs 38 cm(3)/min; P < 0.05).<h4>Conclusions</h4>This study confirms that perforator size is a critical factor in optimizing blood flow in perforator-based free tissue transfer. Further research is required to understand the flow dynamics of perforator flaps based on multiple perforators. However, surgeons should be cognizant that a single large perforator may have substantially higher flow rates than multiple small perforators. Routine FVI calculation is recommended to ensure complete flap survival.
Project description:<h4>Background</h4>Preoperative CTA is widely used and extensively studied for planning of DIEP flap breast reconstruction. However, its utility in planning robotic DIEP harvest is undescribed.<h4>Methods</h4>The authors conducted a retrospective study of consecutive patients presenting to the clinics of select plastic surgeons between 2017 and 2021 for abdominally based autologous breast reconstruction. CTA measurements of intramuscular perforator distance and perforator-to-external iliac distance were used as predicted robotic and open fascial incision lengths, respectively. It was documented if the predicted robotic incision would avoid crossing the arcuate line. Operative notes were reviewed for fascial incision length and number of perforators harvested. Predicted and actual robotic fascial incision lengths were compared.<h4>Results</h4>CTAs were reviewed for 49 patients (98 hemiabdomens). Inadequate or no perforators were identified on CTA in 18% of hemiabdomens. Mean predicted robotic and open DIEP fascial incisions were 3.1 cm and 12.2 cm, respectively, giving robotic approach fascial incision benefit of 9.1 cm (<i>P</i> < 0.001). The predicted robotic incision avoided crossing the arcuate line in 71% of hemiabdomens. Thirteen patients (28%) underwent robotic DIEP harvest. Actual robotic fascial incision length averaged 3.5 cm, which was not significantly different from the mean predicted fascial incision length (<i>P</i> = 0.374). Robotic DIEP flaps had fewer perforators (1.8 versus 2.6, <i>P</i> = 0.058).<h4>Conclusion</h4>CTA is useful for identifying patients with anatomy favorable for robotic DIEP flap harvest.
Project description:Dynamic infrared thermography (DIRT) has been used for the preoperative mapping of cutaneous perforators. This technique has shown a positive correlation with intraoperative findings. Our aim was to evaluate the accuracy of perforator mapping with DIRT and augmented reality using a portable projector. For this purpose, three volunteers had both of their anterolateral thighs assessed for the presence and location of cutaneous perforators using DIRT. The obtained image of these "hotspots" was projected back onto the thigh and the presence of Doppler signals within a 10-cm diameter from the midpoint between the lateral patella and the anterior superior iliac spine was assessed using a handheld Doppler device. Hotspots were identified in all six anterolateral thighs and were successfully projected onto the skin. The median number of perforators identified within the area of interest was 5 (range, 3-8) and the median time needed to identify them was 3.5 minutes (range, 3.3-4.0 minutes). Every hotspot was correlated to a Doppler sound signal. In conclusion, augmented reality can be a reliable method for transferring the location of perforators identified by DIRT onto the thigh, facilitating its assessment and yielding a reliable map of potential perforators for flap raising.
Project description:CT angiography (CTA) is an established technique that allows preoperative planning in DIEP flap reconstruction. However, innovative technological developments with extensive amounts of information require processing of data. It also requires user knowledge to interpret findings. Descriptions by radiologists are many times disappointingly limited to caliber and exit points of the perforator from the rectus fascia. Many DIEP flap surgeons similarly fail to utilize the CTA to its full extent. This is likely due to information overload. By tracing the DIEA on the CTA on a computer screen, using an ordinary ballpoint pen and a white sheet of paper, the surgeon can create a stylistic map of the dissectional-path of the DIEA. The map illustrates unusual branching patterns, perforator caliber and location, interconnections between individual perforators (or lack thereof), length of intramuscular dissection, and also rectus abdominis muscle intersections. The mapping can help in the choice of perforator(s) and may also speed up decision-making during surgical dissection. A penciled map also eases a round-table discussion, if multiple surgeons are involved in the operation. The map can also easily be brought to the operating room for guidance. Tracing is a user-friendly, time-efficient, intuitive, low-cost, and low-tech method that generates data that are easy to interpret, easy to share, and easy to discuss with other surgeons. The method is also not dependent on a radiologist for interpretation.
Project description:Precise perforator mapping of the epifascial and subcutaneous course of the perforator flaps, including the precise detection of the skin point, is mandatory for successful preoperative flap design and planning of supramicrosurgery. We investigated the effectiveness of contrast-enhanced B-flow (BCEUS) imaging for perforator mapping and preoperative perforator flap planning and compared it with B-flow ultrasound, contrast-enhanced ultrasound, and color Doppler ultrasound. Sixteen patients who received an individualized perforator flap reconstruction were included in the study. Preoperative perforator mapping includes the following structures: subfascial course of the pedicle, fascial penetration point, subcutaneous course (epifascial and subcutaneous), and perforator skin point. The precision of the preoperative perforator mapping was analyzed for color Doppler ultrasound, contrast-enhanced ultrasound, B-flow ultrasound, and BCEUS. Each technique was able to precisely display the subfascial course of the vascular pedicle, including the fascial penetration point. However, only BCEUS enabled precise mapping of the epifascial and subcutaneous (suprafascial) course, including the skin point of the perforators with a clear delineation. Precise knowledge of the suprafascial course of the perforators is mandatory for successful supermicrosurgery and perforator flap planning. BCEUS imaging facilitates full perforator mapping, which improves the safety of flap harvesting. However, BCEUS is technically demanding and requires an experienced sonographer.
Project description:Although the success rate of deep inferior epigastric perforator (DIEP) flaps has increased, late flap failures still occur and have a low salvage rate. The present article describes a case of salvage of a case of late flap failure using the pedicle vein as a vein graft source. A 50-year-old woman underwent a bilateral DIEP free flap procedure. On postoperative day 6, she experienced flap compromise and underwent emergency flap revision. In the flap revision, flap venous drainage and the superficial inferior epigastric vein were completely obstructed. A Fogarty catheter was used to remove a thrombus from the completely obstructed pedicle vein, and this pedicle vein was used as a graft source and was ligated in retrograde fashion to the flap vein stump. After injection of urokinase into the arterial branch, venous flow to the flap was restored. At a 6-month follow-up visit in the outpatient clinic, only partial fat necrosis at the flap was noted. By dissecting various perforators in the initial operation, decisions regarding immediate revision can be made with more confidence. Additionally, the combined procedures performed in this case may be helpful even for practitioners treating cases of late flap compromise.
Project description:Background: Breast cancer is the most common malignancy in women. The interdisciplinary treatment is based on the histological tumor type, the TNM classification, and the patient's wishes. Following tumor resection and (neo-) adjuvant therapy strategies, breast reconstruction represents the final step in the individual interdisciplinary treatment plan. Although manifold flaps have been described, abdominal free flaps, such as the deep inferior epigastric artery perforator (DIEP) or the muscle-sparing transverse rectus abdominis myocutaneous (ms-TRAM) flap, are the current gold standard for autologous breast reconstruction. This retrospective study focuses on the safety of autologous breast reconstruction upon mastectomy using abdominal free flaps. Methods: From April 2012 until December 2018, 193 women received 217 abdominal free flaps for autologous breast reconstruction at the University Hospital of Erlangen. For perforator mapping, we performed computed tomography angiography (CTA). Venous anastomosis was standardized using a ring pin coupler system, and flap perfusion was assessed with fluorescence angiography. A retrospective analysis was performed based on medical records, the surgery report, and follow-up of outpatient course. Results: In most cases, autologous breast reconstruction was performed as a secondary reconstructive procedure after mastectomy and radiotherapy. In total, 132 ms1-TRAM, 23 ms2-TRAM, and 62 DIEP flaps were performed with 21 major complications (10%) during hospital stay including five free flap losses (2.3%). In all cases of free flap loss, we found an arterial thrombosis as the main cause. In 24 patients a bilateral breast reconstruction was performed without free flap loss. The majority of free flaps (96.7%) did not need additional supercharging or turbocharging to improve venous outflow. Median venous coupler size was 2.5 mm (range, 1.5-3.5 mm). Conclusion: Using CTA, intraoperative fluorescence angiography, titanized hernia meshes for rectus sheath reconstruction, and venous coupler systems, autologous breast reconstruction with DIEP or ms-TRAM free flaps is a safe and standardized procedure in high-volume microsurgery centers.
Project description:<h4>Background</h4>We developed a novel pedicled DIEP flap model in rat to explore the possible remedy for the distal necrosis of the flap.<h4>Methods</h4>A deep inferior epigastric perforator (DIEP) flap, based on the second right cranial perforator (P2) as the main pedicle, was elevated in 48 Sprague-Dawley rats. The rats were randomized into 4 groups: group I, the left P2 remaining intact as supercharging; group II, the left P2 artery alone kept as supercharging; group III, the left P2 vein alone kept as supercharging; group IV, no supercharging. Transcutaneous oxygen pressure (TcPO2) and transcutaneous carbon dioxide pressure (TcPCO2) were measured immediately after flap elevation, protein level of Hif-1a was measured 48 hours later, and flap survival was assessed 7 days postoperatively.<h4>Results</h4>Blockade of artery led to significantly lower TcPO2, higher TcPCO2, and higher expression level of Hif-1a in the distal side of the flap in group III and group IV, than those of group I and group II. At 7 days post surgery, significantly lower flap survival rates were observed in group III (81.9 ± 5.7%) and group IV (78.4 ± 6.5%), compared to observed in group I (97.2 ± 3.0%) and group II (94.2 ± 6.2%).<h4>Conclusions</h4>It might be arterial insufficiency, not venous congestion, which mainly caused the distal necrosis of the DIEP flap in rat. Arterial instead of venous supercharging might be a more effective procedure that improves circulation to zone IV of the flap.
Project description:<b>Background: </b>Thermal imaging was first reported as a method for detection of arterial perforators in 1968 and has since been shown to be an extremely accurate way to assess perforators with an audible Doppler signal, using high-end professional thermal cameras. This technology has recently become easily accessible with the advent of smartphone-compatible, low-end thermal cameras. Several groups have reported on the use of these devices in the pre-, intra-, and postoperative phase, yet there have been few attempts to validate them against existing methods or compare them with high-end thermal cameras.<br><br><b>Methods: </b>The aim of this study was to compare a low-end smartphone-compatible thermal camera, the FLIR ONE Pro (ONEPro), priced US $400, with a high-end thermal camera the FLIR A35sc (A35sc), priced US $5000, for the detection of arterial perforators on the anterolateral thigh, using a handheld Doppler and Color Doppler Ultrasound to verify the results.<br><br><b>Results: </b>We examined 23 thighs in 13 healthy volunteers and identified a total of 779 hotspots using both cameras. The A35sc identified on average 33.5 hotspots per thigh. The ONEPro identified on average 31.5 hotspots per thigh. Using a handheld Doppler, we confirmed 95.9% of hotspots identified with the ONEPro and 95.8% of hotspots identified with the A35sc. Using Color Doppler Ultrasound, we confirmed 95% of hotspots identified using the ONEPro and 94.9% of hotspots identified with the A35sc.<br><br><b>Conclusion: </b>While the high-end camera identified slightly more hotspots, verification data were very similar for the 2 cameras, and for clinical purposes these differences are negligible.