Intraoperative Indocyanine Green Angiography Research Articles

Practicality and Hemodynamic Advantage of Microvascularly Augmented Pectoralis Major Musculocutaneous Flap: Technical Approach and Evidence Based on Indocyanine Green Angiography.

We have recently shown that including the blood flow from the lateral thoracic artery (LTA) in addition to the thoracoacromial artery in the pectoralis major muscle musculocutaneous (PMMC) flap (bipedicle PMMC flap) can increase the perfusion of the flap. We also developed the concept of the supercharged PMMC flap, in which the LTA included in the flap was once cut and anastomosed to a cervical artery under a microscope. It is an effective solution to maintain the additional blood flow from the LTA, when the length of the LTA is compromised for reconstruction. The mandibular reconstruction of an oral cancer patient was performed with a supercharged PMMC flap. Intraoperative indocyanine green angiography was performed in a single pedicle, bipedicle, and supercharged conditions, and the videos were analyzed with a quantitative assessment system of perfusion using some parameters. As a result, blood supply from the LTA was essential for flap survival in this patient, and supercharging from the cervical artery improved flap perfusion compared with the perfusion in the bipedicle condition. The supercharged PMMC flap can resolve the compromise of pedicle length and be also hemodynamically advantageous, thus making the reconstruction more reliable than the conventional technique.

D157. Intraoperative Indocyanine Green Angiography for Detecting Quantitative Flap Perfusion Changes in Deep Inferior Epigastric Perforator Flap Breast Reconstruction with Second Venous Drainage

D157. Intraoperative Indocyanine Green Angiography for Detecting Quantitative Flap Perfusion Changes in Deep Inferior Epigastric Perforator Flap Breast Reconstruction with Second Venous Drainage

Outcomes of nonrejection in weakly fluorescent intestine detected by indocyanine green fluorescence angiography: a case series of infants

BackgroundIndocyanine green fluorescence angiography, a validated noninvasive imaging technique, is used to assess tissue vascularization. Here, we report three infant patients who underwent intraoperative indocyanine green fluorescence angiography and suffered from postoperative complications caused by the lack of weak fluorescent intestinal resection and assessed residual intestinal perfusion.Case presentationWe observed the clinical characteristics and operative findings of patients treated from January 2022 to December 2022. Indocyanine green (0.5 mg/kg) was intravenously injected. The first patient was a 29-day-old girl with surgical necrotizing enterocolitis who underwent intraoperative indocyanine green fluorescence angiography at the first- and second-look operations. The proximal jejunum was difficult to diagnose to detect blood flow during the second-look operation. The second patient was a 32-day-old boy with surgical necrotizing enterocolitis. A part of the antimesenteric mucosa of the patient that exhibited weak fluorescence was preserved; however, it formed postoperative hematomas. The third patient was a 30-day-old boy with midgut volvulus. Weak fluorescence in the intestinal wall was observed 5 cm of the small intestine from the ileocecal valve was preserved, but it formed a stricture, and the patient underwent ileocecal resection after 30 days.ConclusionsWeak fluorescence in the intestine in infants by performing indocyanine green fluorescence angiography is associated with a high risk of non-recovering ischemic lesions and postoperative complications.

Clinical and computational development of a patient-calibrated ICGFA bowel transection recommender.

Intraoperative indocyanine green fluorescence angiography (ICGFA) aims to reduce colorectal anastomotic complications. However, signal interpretation is inconsistent and confounded by patient physiology and system behaviours. Here, we demonstrate a proof of concept of a novel clinical and computational method for patient calibrated quantitative ICGFA (QICGFA) bowel transection recommendation. Patients undergoing elective colorectal resection had colonic ICGFA both immediately after operative commencement prior to any dissection and again, as usual, just before anastomotic construction. Video recordings of both ICGFA acquisitions were blindly quantified post hoc across selected colonic regions of interest (ROIs) using tracking-quantification software and computationally compared with satisfactory perfusion assumed in second time-point ROIs, demonstrating 85% agreement with baseline ICGFA. ROI quantification outputs detailing projected perfusion sufficiency-insufficiency zones were compared to the actual surgeon-selected transection/anastomotic construction site for left/right-sided resections, respectively. Anastomotic outcomes were recorded, and tissue lactate was also measured in the devascularised colonic segment in a subgroup of patients. The novel perfusion zone projections were developed as full-screen recommendations via overlay heatmaps. No patient suffered intra- or early postoperative anastomotic complications. Following computational development (n = 14) the software recommended zone (ROI) contained the expert surgical site of transection in almost all cases (Jaccard similarity index 0.91) of the nine patient validation series. Previously published ICGFA time-series milestone descriptors correlated moderately well, but lactate measurements did not. High resolution augmented reality heatmaps presenting recommendations from all pixels of the bowel ICGFA were generated for all cases. By benchmarking to the patient's own baseline perfusion, this novel QICGFA method could allow the deployment of algorithmic personalised NIR bowel transection point recommendation in a way fitting existing clinical workflow.

1227 Superior Hypophyseal Artery Intraoperative Indocyanine Green Angiogram as a Predictor of Postoperative Visual Function After Endoscopic Endonasal Surgery

INTRODUCTION: To date, there are no tools to intraoperatively predict postoperative visual function following endoscopic endonasal surgery (EES) for suprasellar lesions. The development of such a tool would impact postoperative care for patients at risk of new visual deficits. METHODS: Patients undergoing EES for resection of suprasellar lesions were administered 5 mg of ICG diluted in 10 mL of saline after tumor removal. Time between luminescence of the anterior cerebral artery and the superior hypophyseal artery branches enveloping the optic chiasm was noted, and the percentage of optic chiasm vessels that luminesced was recorded. Postoperative exams and imaging studies were then used to assess visual function. Patients with and without new deficits were compared to examine trends in ICG findings. RESULTS: A total of seven trials were performed on six patients. Mean time to chiasm peak luminescence was 3.8 seconds, and 81.8% of chiasm vessels luminesced. Patients with stable or improved vision after resection demonstrated over 90% chiasm luminescence in every case, and mean time to chiasm luminescence in these post-resection ICG administrations was 4.0 seconds. One patient experienced new postoperative visual deficits; on review of their ICG administration, 11.5% of chiasm vessels luminesced, and the chiasm itself failed to display robust luminescence after 30 seconds of direct observation. CONCLUSIONS: This pilot study showed the capability of intraoperative indocyanine green angiography to demonstrate perfusion of the optic chiasm during endoscopic endonasal surgery for resection of suprasellar lesions. Chiasm times under 5 seconds and over 90% chiasm vessel illumination may reflect adequate chiasm perfusion, while those with delayed or absent chiasm luminescence may have compromised chiasm perfusion.

Surgical considerations and techniques using intraoperative indocyanine green angiography for ethmoidal dural arteriovenous fistula.

This study aims to investigate the efficacy of microsurgery with intraoperative indocyanine green (ICG) angiography as a treatment approach for ethmoidal dural arteriovenous fistula (DAVF). Between January 2010 and July 2021, our institution encountered a total of eight cases of ethmoidal DAVF. In each of these cases, microsurgical treatment was undertaken utilizing a bilateral sub-frontal interhemispheric approach, with the aid of intraoperative ICG angiography. ICG angiography identified bilateral venous drainage with single dominance in four cases (50%) of ethmoidal DAVF, a finding that eluded detection during preoperative transfemoral cerebral angiography (TFCA). The application of microsurgical treatment, in conjunction with intraoperative ICG angiography, resulted in consistently positive clinical outcomes for all patients, as evaluated using the Glasgow Outcome Scale (GOS) at the 6-month postoperative follow-up assessment; six patients showed GOS score of 5, while the remaining two patients attained a GOS score of 4. The use of intraoperative ICG angiography enabled accurate identification of both dominant and non-dominant venous drainage patterns, ensuring complete disconnection of the fistula and reducing the risk of recurrence.

A Challenging Case of Thumb Replantation Aided by Intraoperative Indocyanine Green Fluorescence Angiography

Background: This study presents a case of thumb replantation performed despite several risk factors: age, comorbidities, and trauma mechanism are major adverse prognostic factors directly impacting thumb replantation. Most of the literature backs up this claim that a thumb that works, even partially, is a better outcome for the patient than amputation. Methods: We performed thumb replantation on a 94-year-old patient with type 2 diabetes mellitus who arrived at the emergency department with a thumb avulsion due to a dog bite. The intraoperative indocyanine green fluorescence angiography method aided us in carrying out the operation. Results: We successfully used indocyanine green angiography intraoperatively to guide surgical debridement and evaluate the efficacy of anastomosis and reperfusion of the replanted segment during surgery. Two months after the operation, the patient had regained satisfactory hand function. Conclusions: Although indocyanine green angiography is not a technology created for revascularization procedures, it is instrumental in assessing vascular function and predicting a successful outcome. Given its undeniable potential, more research is needed on the possibility of widespread use in hand surgery and its indications.

The Value of Intraoperative Indocyanine Green Angiography to Assess Anastomotic Perfusion and Leakage in Patients Undergoing Laparoscopic Colorectal Resection: a Randomized Controlled Clinical Trial

The Value of Intraoperative Indocyanine Green Angiography to Assess Anastomotic Perfusion and Leakage in Patients Undergoing Laparoscopic Colorectal Resection: a Randomized Controlled Clinical Trial

Use of indocyanine green angiography during endoscopic microvascular decompression for trigeminal neuralgia

BackgroundThe aim of this study was to assess the efficacy of indocyanine green (ICG) angiography during full endoscopic microvascular decompression for trigeminal neuralgia. MethodsWe extracted retrospective data of patients who received ICG videoangiography during full endoscopic microvascular decompression for trigeminal neuralgia. Preoperative neurovascular contact was evaluated by three-dimensional (3D) fusion images using image analysis software Ziostation2 (ZIOSOFT, Tokyo, Japan) and Intraoperative ICG angiography was used in pre and post ICG injection to identify and assess blood flow in the offending vessel for adequate transposition planification and assess for immediate post transposition blood flow or vasospasm respectively. Patients were assessed the next morning for early signs of brainstem infarction and at one month follow up. ResultsThere were 44 patients. All patients had ICG videoangiography done during the procedure. The mean age was 65.5 and male female ratio 3.4:1. Some anatomical variants were identified during this procedure. Five patients (11.3%) had a trigeminocerebellar artery, three patients (6.8%) had a developed superior petrosal vein and one patient (2.2%) had dural adhesions with encasement of anterior inferior cerebellar artery. Among the 44 patients enrolled, 34 had transposition done and 10 had combined transposition either with neurolysis or Teflon interposition. The main offending vessel was Superior cerebellar artery (SCA) in 23 patients (67.6%). In 5 (14.7%) of 34 patients who underwent Transposition, vasospasm was seen and no complications were observed in all patients but 93.1% had good pain control in postoperative. ConclusionICG angiography in endoscopic microvascular decompression is safe and effective in depicting the offending vessel, its branches and some perforators and contributes significantly to the determination of treatment strategy.

Intraoperative indocyanine green angiography for predicting postoperative hypoparathyroidism.

Postoperative hypocalcemia is a common complication of thyroidectomy. This problem is most often associated with accidental devascularization or excision of the parathyroid glands (PG). Aim was to study near-infrared (NIR) fluorescent imaging with intraoperative PG indocyanine green (ICG) angiography to help identify and preserve PG during total thyroidectomy in order to avoid postoperative hypocalcemia. From 2017 to 2022, a total of 92 patients underwent total thyroidectomy at Odessa Regional Hospital. Indications for surgery were multinodular goiter (n = 42), thyroid cancer (n = 43), and Graves' disease (n = 7). By randomization all patients were divided into two groups: in the control group, 48 patients underwent standard total thyroidectomy, and in the main group, 44 patients underwent NIR-assisted total thyroidectomy with ICG angiography. Serum calcium and parathyroid hormone levels were compared between the two groups of patients in 1, 7-15days after surgery and then 3, 6months later. In the control group, based on a visual assessment of the PG, autotransplantation of the PG was conducted in only five cases. In the second group, autotransplantation was performed in 16 patients. The transient postoperative hypocalcemia was observed in 8 patients of the control group (16, 70%) and in the 2 patients of ICG group (4, 50%) on 5-10 postoperative days. In the first group, 2 patients at 3months after surgery had permanent hypocalcaemia. NIR fluorescent imaging with intraoperative PG ICG angiography is a safe and an easily repeatable method. This technique provides improved detecting and assessment of the perfusion of the PG. The need for autotransplantation of the PG can be determined more objectively using ICG imaging than simple visualization.

Evaluation of Intraoperative Anastomotic Patency with Angiography in Microsurgical Breast Reconstruction.

Microsurgical breast reconstruction is one of the most challenging, yet rewarding procedures performed by plastic surgeons. Several measures are taken to ensure safe elevation of the flap, preparation of recipient vessels, microvascular anastomosis, and flap inset. Reestablishing proper blood flow to the flap tissue after microvascular anastomosis is one of many critical steps for surgical success. Several measures to assess blood flow to the flap have been used; however, the use of indocyanine green angiography (ICGA) of the anastomosis in breast reconstruction has not been well documented. We present a series using ICGA for the evaluation of microvascular anastomosis success in breast reconstruction. Cases from patients who underwent microsurgical breast reconstruction between March 2022 and January 2023 and who had intraoperative ICGA were retrospectively reviewed. We compared the intraoperative findings on ICGA to flap success. Sixteen patients underwent bilateral deep inferior epigastric perforator flap reconstruction with intraoperative ICGA of the microvascular anastomosis, constituting 32 deep inferior epigastric perforator flaps. The ICGA demonstrated return of blood flow in all the flaps after microvascular anastomosis and no flap loss in our sample population. Nine flaps required additional drainage using the superficial inferior epigastric vein, and the superficial circumflex vein was used for additional drainage in one of the flaps. The use of intraoperative ICGA provides reliable visual feedback regarding the patency and direction of the blood flow through the microvascular anastomosed vessels. ICGA can be used as an additional tool in the plastic surgeon's armamentarium for successful breast reconstruction.

Reduction of Uncertainty in Bolus Transit Time Measurement in Quantitative Fluorescence Angiography

Abstract During cerebral revascularization surgeries, blood flow values help surgeons to monitor the quality of the procedure, e.g., to avoid cerebral hyperperfusion syndrome due to excessively enhanced perfusion. The state-of-the-art technique is the ultrasonic flow probe that has to be placed around the blood vessel. This causes contact between probe and vessel, which, in the worst case, leads to rupture. The recently developed intraoperative indocyanine green (ICG) Quantitative Fluorescence Angiography (QFA) is an alternative technique that overcomes this risk. However, it has been shown by the developer that the calculated flow has deviations. After determining the bolus transit time as the most sensitive parameter in flow calculation, we propose a new two-step uncertainty reduction method for flow calculation. The first step is to generate more data in each measurement that results in functions of the parameters. Noise can then be reduced in a second step. Two methods for this step are compared. The first method fits the model for each parameter function separately and calculates flow from models, while the second one fits multiple parameter functions together. The latter method is proven to perform best by in silico tests. Besides, this method reduces the deviation of flow comparing to original QFA as expected. Our approach can be generally used in all QFA applications using two-point theory. Further development is possible if number of dimensions of the achieved parameter data are broadened that results in even more data for processing in the second step.

Outcome analysis of free flap reconstruction for head and neck cancer with intraoperative indocyanine green angiography

Intraoperative indocyanine green (ICG) angiography is used in free flap surgery to evaluate the patency of vessel anastomosis. This study evaluated the outcomes of intraoperative ICG angiography in free flap surgery for head and neck cancer. This was a retrospective study of free flap reconstruction for head and neck cancer performed between 2015 and 2021. The outcomes analyzed were the total flap failure rate, re-exploration rate, and flap salvage rate. Differences in outcomes were compared in patients treated using intraoperative ICG angiography and those treated without. Of the 520 free flap surgeries in the 486 enrolled patients, 259 cases underwent intraoperative ICG angiography. In this group, there were 10 (3.9%) cases of total flap failure. In the non-ICG group, there were 22 cases (8.4%). There were 35 (13.5%) cases requiring re-exploration in the ICG group and 40 (15.3%) in the non-ICG group. The difference was not statistically significant. The flap salvage rate was 75.8% (25/33) in the ICG group and 51.4% (18/35) in the non-ICG group, which was a significant difference. We found that free flap surgery with intraoperative ICG angiography significantly decreased total flap failure rate and significantly increased salvage rate but did not significantly affect the re-exploration rate.

Indocyanine green angiography in oncoplastic breast surgery, a prospective study

The use of Indocyanine green angiography (ICG-A) in oncoplastic breast-conserving surgery (OBCS) has not yet been investigated. This prospective trial applied ICG-A in volume displacement and replacement OBCS to localize perforators and determine tissue supplied by the perforator. Furthermore, to investigate and correlate the intraoperative ICG-A to postoperative surgical site infection, skin necrosis, epidermolysis, and timely onset of adjuvant therapy. ICG-A was performed at three pre-set timepoints during surgery; after lumpectomy, upon dissection of possible perforators, and after wound closure. All patients were followed with clinical evaluations before surgery, 4 weeks, 4-6 months, and 12 months postoperatively. Eleven patients were included: seven volume displacement and four volume replacement OBCS. ICG-A located the tissue supplied by the perforator and demonstrated sufficient perfusion in all cases. The ICG-A corresponded to the surgeons' clinical assessment. One patient developed a postoperative infection and seroma and was treated conservatively. No patients had postoperative necrosis, loss of reconstruction, or lymphedema of the arm. Edema of the breast occurred in four patients (36.4%). Scar assessments were significantly worse at 4-weeks and 4-6 months. The quality of life improved significantly during follow-up. Adjuvant treatment was administered timely in all cases. ICG-A was feasible for OBCS in assessing intraoperative perfusion. Perfusion was sufficient in all patients and corresponded to the surgeon's clinical evaluation. No patients developed postoperative necrosis. Though edema of the breast occurred in 36.4%, a larger sample size is needed to investigate a possible correlation with ICG-A. Further studies, which includes patients requiring extensive tissue replacement challenging the borders of perfusion, are needed.

Interpreting Lower Trapezius Musculocutaneous Flap Skin Paddle Perfusion with Indocyanine Green Angiography.

Background: The lower trapezius myocutaneous flap (LTF) is a pedicled flap with clinically significant variability of distal skin flap perfusion. Objective: To compare the incidence of partial flap necrosis before and after the institution of routine intraoperative laser-assisted indocyanine green (ICG) angiography. Methods: This is a retrospective review of all LTF performed between November 2021 and July 2022. The outcomes measured in this study are the distance distal to the inferior border of the trapezius muscle with adequate perfusion, and incidence and degree of partial flap necrosis. Results: Sixteen patients met inclusion criteria with a median age of 64.5 years, and a median defect size of 147 cm2. Most patients (11/16) had undergone previous treatment for malignancy. Before utilizing ICG angiography, 40% (2/5) had partial flap necrosis, whereas after utilizing ICG angiography, 9% (1/11) of patients had partial flap necrosis. Seventy-three percent (8/11) of cases who underwent ICG angiography demonstrated a portion of the skin paddle with inadequate perfusion. The range of skin perfusion distal to the inferior border of the trapezius muscle was 0-7 cm (median, 4). Conclusions: The incidence of partial flap necrosis decreased after institution of routine ICG angiography.

Intraoperative Indocyanine Green Angiography Facilitates Flap Fenestration and Facial Organ Fabrication in Total Facial Restoration.

As effective measures to visualize flap vasculature and perfusion were unavailable, flap fenestration and facial organ fabrication could not be performed safely, preventing the transition from 2-D coverage to the restoration of the 3-D structure of facial organs. This study aims to evaluate the efficacy of indocyanine green angiography (ICGA) in guiding flap fenestration and facial organ fabrication in total facial restoration. Ten patients with total facial scarring following burn injury were enrolled in the study. They were treated with pre-expanded, prefabricated monoblock flaps for total face restoration. The opening of nostrils, oral and palpebral orifices, together with organ fabrication, were conducted under the guidance of intraoperative ICGA via hemodynamic evaluation of flap perfusion. Postoperative follow-up parameters include vascular crisis, infection, flap necrosis and patients' aesthetic and functional recovery. The opening of facial organ orifices was performed at the stage of flap transfer in nine patients. To avoid damaging the major nourishing vessels, the left palpebral orifice was opened eight days after the flap transfer in one patient, as observed by ICGA. Based on ICGA evaluation, the decision to perform additional vascular anastomosis before flap fenestration was made in six patients. Hemodynamic analysis of flap perfusion following fenestration revealed no significant change. Follow-up showed satisfactory aesthetic recovery and well-restored 3-D structures of facial organs. This pilot study demonstrates how intraoperative ICGA can enhance the safety of flap fenestration, thereby transforming full facial restoration from the 2-D to the 3-D realm by facilitating facial organ fabrication.

Superior Hypophyseal Artery Intraoperative Indocyanine Green Angiogram as a Predictor of Postoperative Visual Function After Endoscopic Endonasal Surgery.

To date, there are no tools to intraoperatively predict postoperative visual function after endoscopic endonasal surgery (EES) for suprasellar lesions. The objective of this study was to retrospectively evaluate the utility of indocyanine green (ICG) angiography as an intraoperative tool to measure optic chiasm perfusion and determine its relationship with postoperative visual function. Videos of patients undergoing EES for resection of suprasellar lesions were reviewed, where 5 mg of ICG was diluted in 10 mL of saline and administered. Time between luminescence of the anterior cerebral artery and the superior hypophyseal artery branches supplying the optic chiasm was noted, and the percentage of optic chiasm vessels that luminesced was recorded. Postoperative examinations and imaging studies were used to assess visual function. Patients with and without new deficits were compared with examination of trends in ICG findings. A total of 7 trials were reviewed on 6 patients, with no complications occurring from ICG administration. Mean time to chiasm peak luminescence was 3.8 seconds, and 81.8% of chiasm vessels luminesced. Patients with stable or improved vision after resection demonstrated over 90% chiasm luminescence in every case, and mean chiasm time in these postresection ICG administrations was 4.0 seconds. One patient experienced new postoperative visual deficits; on review of their ICG administration, 11.5% of chiasm vessels luminesced, and the chiasm itself failed to display robust luminescence after 30 seconds of direct observation. This pilot study showed the capability of intraoperative ICG angiography to demonstrate perfusion of the optic chiasm during EES for resection of suprasellar lesions. While larger studies are required, preliminary results suggest chiasm times under 5 seconds and over 90% chiasm vessel illumination may reflect adequate chiasm perfusion, while those with delayed or absent chiasm luminescence may have compromised chiasm perfusion.

Efficacy of superficial inferior epigastric vein superdrainage in free TRAM and DIEP flap: An indocyanine green angiography study of 68 cases

This study aimed to evaluate the clinical efficacy of venous augmentation using superficial inferior epigastric vein (SIEV) in free transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric artery perforator (DIEP) flap and investigate the factors that hinder the venous superdrainage. A retrospective review of 62 free muscle-sparing (MS)-TRAM and 6 DIEP unilateral breast reconstructions from September 2017 to July 2022. Intraoperative indocyanine green angiography was performed on the harvested flap, with the SIEV contralateral to the pedicle side clamped and unclamped for 20min. The relative ratio of hypoperfused area to the total flap area was calculated and compared quantitatively. The preoperative computed tomography (CT) angiography was reviewed to obtain information on the SIEV diameter and number of midline-crossing medial branches. The participants were categorized into three groups: 42 patients in Group 1 (>3% decrease in hypoperfused area), 20 patients in Group 2 (change in hypoperfused area ranging from -3% to 3%), and six patients in Group 3 (>3% increase in hypoperfused area). The mean number of midline-crossing branches (p=0.002) and mean difference in the diameter of bilateral SIEVs (p=0.039) were significantly greater in Group 1 than in the other groups. Thirty-eight percent (26/68 cases) resulted in sustained or aggravated perfusion after SIEV superdrainage. Superdrainage using the contralateral SIEV in free MS-TRAM/DIEP flap is recommended when there are more than two midline-crossing medial branches of SIEV and when the caliber of SIEV is relatively greater compared with the pedicle side.

Preoperative visualization of midline-crossing subcutaneous arteries in transverse abdominal flaps using photoacoustic tomography

Photoacoustic tomography is a noninvasive vascular imaging modality that uses near-infrared pulsed laser light and ultrasound to visualize vessels. We previously demonstrated the utility of photoacoustic tomography for anterolateral thigh flap surgery involving body-attachable vascular mapping sheets. However, it was not possible to obtain clear separate images of arteries and veins. In this study, we tried to visualize subcutaneous arteries that cross the midline of the abdomen, since these arteries are known to be important for obtaining large perfusion areas in transverse abdominal flaps. Four patients scheduled to undergo breast reconstruction with abdominal flaps were examined. Photoacoustic tomography was performed preoperatively. The tentative arteries and veins were traced according to the S-factor, an approximate hemoglobin oxygen saturation parameter calculated using 2 laser excitation wavelengths (756 and 797nm). Intraoperatively, arterial-phase indocyanine green (ICG) angiography was performed after abdominal flap elevation. Images of vessels speculated to be arteries by preoperative photoacoustic tomography were merged with those of intraoperative ICG angiography and analyzed in an 8×4-cm2 area below the umbilical region. The S-factor was used to visualize the midline-crossing subcutaneous arteries in all 4 patients. A matching analysis compared preoperative tentative arteries according to photoacoustic tomography with ICG angiography results in the 8×4-cm2 area below the umbilical region and indicated a 71.3-82.1% match (average: 76.9% match). This study demonstrates that the S-factor, a noninvasive, label-free imaging modality, can be used to successfully visualize subcutaneous arteries. This information can aid in selecting perforators for abdominal flap surgery.

Flap perfusion assessment with indocyanine green angiography in deep inferior epigastric perforator flap breast reconstruction: A systematic review and meta-analysis.

Indocyanine green angiography (ICG-A) has been widely applied for intraoperative flap assessment in DIEP flap breast reconstruction. However, the beneficial effect of ICG-A in DIEP flap breast reconstruction is still uncertain and no standardized protocol is available. This study aims to analyze the clinical outcome and comprehensively review protocols of this field. A systematic review was conducted in MEDLINE, EMBASE, and Cochrane CENTRAL databases until September 15, 2022. Studies on the utility of intraoperative ICG-A in DIEP breast reconstruction were included. Data reporting reconstruction outcomes were extracted for pooled analysis. A total of 22 studies were enrolled in the review, among five studies with 1021 patients included in the meta-analysis. The protocols of ICG-A assessment of DIEP flap varied among studies. According to the pooled results, the incidence of postoperative fat necrosis was 10.89% (50 of 459 patients) with ICG-A and 21.53% (121 of 562 patients) with clinical judgment. The risk for postoperative fat necrosis was significantly lower in patients with intraoperative ICG-A than without (RR 0.47 95% CI 0.29-0.78, p = .004, I2 = 51%). Reoperation occurred in 5 of 48 patients (10.42%) in the ICG-A group and in 21 of 64 patients (32.82%) in the control group summarized from reports in two studies. The risk for reoperation was lower in the ICG-A group than in the control group (RR 0.41 95% CI 0.18-0.93, p = .03, I2 = 0%). Other complications, including flap loss, seroma, hematoma, dehiscence, mastectomy skin necrosis, and infection, were comparable between the two groups. Heterogeneities among studies were acceptable. No significant influence of specific studies was identified in sensitivity analysis. ICG-A is an accurate and reliable way to identify problematic perfusion of DIEP flaps during breast reconstruction. Protocols of ICG-A differed in current studies. Intraoperative ICG-A significantly decreases the rate of fat necrosis and reoperation in patients undergoing DIEP breast reconstruction. The synthesized results should be interpreted sensibly due to the sample size limitation. RCTs on the outcomes and high-quality studies for an optimized ICG-A protocol are still needed in the future.