An Innovative Approach for Preoperative Perforator Flap Planning Using Contrast-enhanced B-flow Imaging.
ABSTRACT: 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:The ability to directly harvest thin and superthin perforator flaps without jeopardizing their vascularity depends on knowledge of the microsurgical vascular anatomy of each perforator within the subcutaneous tissue up to the dermis. In this paper, we report our experience with ultrahigh-frequency ultrasound (UHF-US) in the preoperative planning of thin and superthin flaps. Between May 2017 and September 2018, perforators of seven patients were preoperatively evaluated by both ultrasound (using an 18-MHz linear probe) and UHF-US (using 48- and 70-MHz linear probes). Thin flaps (two cases) and superthin flaps (five cases) were elevated for the reconstruction of head and neck oncologic defects and lower limb traumatic defects. The mean flap size was 6.5×15 cm (range, 5×8 to 7.5×23 cm). No complications occurred, and all flaps survived completely. In all cases, we found 100% agreement between the preoperative UHF-US results and the intraoperative findings. The final reconstructive outcomes were considered satisfactory by both the surgeon and the patients. In conclusion, UHF-US was found to be very useful in the preoperative planning of thin and superthin free flaps, as it allows precise anticipation of very superficial microvascular anatomy. UHF-US may represent the next frontier in thin, superthin, and pure skin perforator flap design.
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:The muscle-sparing latissimus dorsi flap relies on perforators from the descending branch of the thoracodorsal artery. Previous descriptions placed a transverse skin island independent of perforator location, as any design was thought to capture enough perforators to ensure flap survival. We have found this approach prone to complications when attempting breast reconstruction in obese patients who require large flap volumes. Although the most proximal perforators have the most reliable blood flow, inclusion of these perforators reduces the arc of rotation, as the flap would be close to the pivot point at the most cranial point of muscle division, leaving significant volume in the axilla. Here we describe a modified skin incision that includes all of the proximal perforators but also allows us free design of the skin island to harvest those areas of the back with maximal subcutaneous tissue and with enough distance from the pivot point to optimize arc of rotation.
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: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:In this report, we present a case of successful treatment of a bowel fistula in the open abdomen by perforator flaps and an aponeurosis plug. A 70-year-old man underwent total gastrectomy and developed anastomotic leakage and dehiscence of the abdominal wound a week later. He was dependent upon extracorporeal membrane oxygenation, continuous hemodiafiltration, and a respirator. Bowel fluids contaminated the open abdomen. Two months after the gastric operation, a plastic surgery team, in consultation with general surgeons, performed perforator flaps on both sides and constructed, as it were, a bridge of skin sealing the orifice of the fistula. The aponeurosis of the external oblique muscle was elevated with the flap to be used as a plug. The perforators of the flaps were identified on preoperative and intraoperative ultrasonography. This modality allowed us to locate the perforators precisely and to evaluate the perforators by assessing their diameters and performing a waveform analysis. The contamination decreased dramatically afterwards. The bare areas were gradually covered by skin grafts. The fistula was closed completely 18 days after the perforator flap. An ultrasoundguided perforator flap with an aponeurosis plug can be an option for patients suffering from an open abdomen with a bowel fistula.
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:<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: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:<h4>Background</h4>Previous studies have reported on the abundant cutaneous perforating blood vessels around the latissimus dorsi (LD) lateral border, such as a thoracodorsal artery perforator (TDAP) of septocutaneous type (TDAP-sc) and muscle-perforating type (TDAP-mp), or the lateral thoracic artery perforator (LTAP). These perforators have been clinically utilized for flap elevation; however, there have been few studies that accurately examined all the cutaneous perforators (TDAP-sc, TDAP-mp, LTAP) around the LD lateral border. Here, we propose a new "whole perforator system" (WPS) concept in the lateral thoracic region and a methodology that enables elevating large flaps with reliable perfusion in a muscle-preserving manner.<h4>Methods</h4>We first performed an anatomical study that verified the number and perforating points of all perforators around the LD lateral border using the results of dynamic contrast-enhanced magnetic resonance imaging of patients with breast cancer. Following the anatomical evaluation, we performed large muscle-preserving flap transfer that contained all of the perforators around the LD lateral border in an actual clinical setting.<h4>Results</h4>A total of 175 latissimus dorsi from 98 patients were included. The mean number of perforators (TDAP-sc + TDAP-mp + LTAP) per side was 4.51±1.44 (2-9); TDAP-sc was present in 57.1% (100/175) of cases, and TDAP-mp in 76.6% (134/175); the TDAP total prevalence rate (TDAP-sc + TDAP-mp) was 96.0% (168/175). The LTAP existence rate was 94.3% (165/175). Distance from the axillary artery to the TDAP-sc was 148.7±56.3 mm, which was significantly proximal to the TDAP-mp (183.8±54.2 mm) and LTAP (172.2±81.3 mm).<h4>Conclusion</h4>The lateral thoracic region has an abundant cutaneous perforator system derived from the descending branch of the thoracodorsal and lateral thoracic arteries. Clinical application of the lateral thoracic WPS flap is promising, with a large survival area even with muscle-preserving procedures and requiring a relatively simple procedure.