Intraoperative Perfusion Assessment Research Articles

Indocyanine green fluorescence angiography for intraoperative assessment of gastrointestinal anastomotic perfusion: a systematic review of clinical trials.

Anastomotic leakage following gastrointestinal surgery remains a frequent and serious complication associated with a high morbidity and mortality. Indocyanine green fluorescence angiography (ICG-FA) is a newly developed technique to measure perfusion intraoperatively. The aim of this paper was to systematically review the literature concerning ICG-FA to assess perfusion during the construction of a primary gastrointestinal anastomosis in order to predict anastomotic leakage. The following four databases PubMed, Scopus, Embase, and Cochrane were independently searched by two authors. Studies were included in the review if they assessed anastomotic perfusion intraoperatively with ICG-FA in order to predict anastomotic leakage in humans. Of 790 screened papers 14 studies were included in this review. Ten studies (n = 916) involved patients with colorectal anastomoses and four studies (n = 214) patients with esophageal anastomoses. All the included studies were cohort studies. Intraoperative ICG-FA assessment of colorectal anastomoses was associated with a reduced risk of anastomotic leakage (n = 23/693; 3.3% (95% CI 1.97-4.63%) compared with no ICG-FA assessment (n = 19/223; 8.5%; 95% CI 4.8-12.2%). The anastomotic leakage rate in patients with esophageal anastomoses and intraoperative ICG-FA assessment was 14% (n = 30/214). None of the studies involving esophageal anastomoses had a control group without ICG-FA assessment. No randomized controlled trials have been published. ICG-FA seems like a promising method to assess perfusion at the site intended for anastomosis. However, we do not have the sufficient evidence to determine that the method can reduce the leak rate.

The Role of Intraoperative Perfusion Assessment: What Is the Current State and How Can I Use It in My Practice?

Evolving intraoperative technology has an increased presence and usefulness in aiding surgeon clinical judgment. Many surgical devices are readily available as an adjunct to this gold standard assessment of adequate tissue perfusion. Intraoperative perfusion monitoring provides surgeons with the ability to interpret additional information that enhances surgical decision-making in real-time. Technologies include various dye-based and non-dye-based near-infrared angiography, tissue oximetry measurements, and ultrasound-based tools. This review summarizes the available intraoperative technologies for planning and assessment of tissue perfusion in plastic and reconstructive surgery. The authors discuss the available literature for the individual devices and supporting evidence for their use. The authors recommend the evidence-based use of these tools in indicated surgical cases to improve clinical outcomes.

An Analysis of Current Techniques Used for Intraoperative Flap Evaluation.

Over the last decade, microsurgeons have used a greater variety of more complex flaps. At the same time, microsurgeons have also become more interested in technology, such as indocyanine green (ICG) angiography, dynamic infrared thermography (DIRT), and photospectrometry, for preoperative planning and postoperative monitoring. These technologies are now migrating into the operating room, and are used to optimize flap design and to identify areas of hypoperfusion or problems with the anastomoses. Although relatively more has been published about ICG angiography, information is generally lacking about the intraoperative role of these techniques. A systematic analysis of articles discussing intraoperative ICG angiography, DIRT, and photospectrometry was performed to better define the sensitivity, specificity, expected outcomes, and potential complications associated with these techniques. For intraoperative ICG angiography, the sensitivity was 90.9% (95% CI: 77.5-100) and the accuracy was 98.6% (95% CI: 97.6-99.7). The sensitivity of DIRT was 33% (95% CI: 11.3-64.6), the specificity was 100% (95% CI: 84.9-100), and the accuracy was 80% (95% CI: 71.2-89.7). The sensitivity of intraoperative photospectrometry was 92% (95% CI: 72.4-98.6), the specificity was 100% (95% CI: 98.8-100), and the accuracy was also 100% (95% CI: 98.7-100). These technologies for intraoperative perfusion assessment have the potential to provide objective data that may improve decisions about flap design and the quality of microvascular anastomoses. However, more work is needed to clearly document their value.

Commentary on: safety of vertical augmentation-mastopexy: prospective evaluation of breast perfusion using laser fluorescence imaging.

As reconstructive or aesthetic surgeons, so much of what we do relies on the ability to maintain appropriate soft tissue perfusion. The consequences of poor tissue perfusion, whether performing a free fibula reconstruction or a facelift, can be devastating. This is why new technologies, such as the SPY Elite Intraoperative perfusion Assessment System (LifeCell Corporation, Branchburg, NJ) are so useful, because they provide us with objective real-time perfusion information. Intraoperative angiography was used in this study to shed some light on an area of much debate: the impact of implant placement to nipple perfusion during augmentation-mastopexy. The major concern that the author wished to address was that of potentially causing nipple ischemia when repositioning the nipple-areolar complex (NAC) and then placing an implant. This is an important concern, since even …

Indocyanine green-enhanced fluorescence to assess bowel perfusion during laparoscopic colorectal resection.

Aims Anastomotic leakage after colorectal surgery is a severe complication. One possible cause of anastomotic leakage is insufficient vascular supply. The aim of this study was to evaluate the feasibility and the usefulness of intraoperative assessment of vascular anastomotic perfusion in colorectal surgery using indocyanine green (ICG)-enhanced fluorescence.MethodsBetween May 2013 and October 2014, all anastomosis and resection margins in colorectal surgery were investigated using fluorescence angiography (KARL STORZ GmbH & Co. KG, Tuttlingen, Germany) intraoperatively to assess colonic perfusion prior to and after completion of the anastomosis, both in right and left colectomies.ResultsA total of 107 patients undergoing colorectal laparoscopic resections were enrolled: 40 right colectomies, 10 splenic flexure segmental resections, 35 left colectomies, and 22 anterior resections. In 90 % of cases, the indication for surgery was cancer and high ligation of vessels was performed. Based on the fluorescence intensity, the surgical team judged the distal part of the proximal bowel to be anastomosed insufficiently perfused in 4/107 patients (two anterior, one sigmoid and one segmental splenic flexure resections for cancer), and consequently, further proximal “re-resection” up to a “fluorescent” portion was performed. None of these patients had a clinical leak. The overall morbidity rate was 30 %; one patient undergoing right colectomy had an anastomotic leakage, apparently unrelated to ischemia; there were no clinical evident anastomotic leakages in colorectal resections including all low anterior resections.ConclusionsICG-enhanced fluorescent angiography provides useful intraoperative information about the vascular perfusion during colorectal surgery and may lead to change the site of resection and/or anastomosis, possibly affecting the anastomotic leak rate. Larger further randomized prospective trials are needed to validate this new technique.

Comparison of Limited and Full Dissection Abdominoplasty Using Laser Fluorescence Imaging to Evaluate Perfusion of the Abdominal Skin

In an effort to reduce risk, some surgeons promote a limited dissection abdominoplasty technique. They believe that preserving musculocutaneous perforators improves blood supply to the overlying abdominal tissue and that improved vascularity avoids seromas and reduces wound healing problems. Laser fluorescence imaging is a new method that allows quantitative measurements of perfusion. Twenty-two consecutive women undergoing abdominoplasty agreed to participate in this prospective study. The inclusion rate was 100 percent. The SPY Elite Intraoperative Perfusion Assessment System was used to quantitate flap perfusion. Patients served as their own controls to avoid confounders. All patients received superwet infusions followed by liposuction of the abdomen and flanks. First, a limited dissection was performed, preserving medial musculocutaneous perforating blood vessels and the Scarpa fascia on the lower abdomen. The rectus fascia was repaired in all cases. A temporary superficial fascial wound closure was performed. The patient was imaged after injection of the contrast agent. The dissection was then extended to a full abdominoplasty and the Scarpa fascia was removed from the lower abdomen. The patient was reimaged. Wound tension was also measured. Complications included one distal deep venous thrombosis, one infection, and one seroma. There were no cases of marginal necrosis or dehiscence. There was no significant difference (p < 0.05) in perfusion measurements comparing the limited and full dissections. Wound tensions were significantly less (p < 0.001) in the full-dissection group. The limited dissection abdominoplasty does not provide a significant improvement in perfusion compared with a full dissection. Therapeutic, II.

Intraoperative Assessment of Perfusion of the Gastric Graft and Correlation With Anastomotic Leaks After Esophagectomy

The aim of the study was to evaluate laser-assisted fluorescent-dye angiography (LAA) to assess perfusion in the gastric graft and to correlate perfusion with subsequent anastomotic leak. Anastomotic leaks are a major source of morbidity after esophagectomy with gastric pull-up (GPU). In large part, they occur as a consequence of poor perfusion in the gastric graft. Real-time intraoperative perfusion was assessed using LAA before bringing the graft up through the mediastinum. When there was a transition from rapid and bright to slow and less robust perfusion, this site was marked with a suture. The location of the anastomosis relative to the suture was noted and the outcome of the anastomosis ascertained by retrospective record review. Intraoperative LAA was used to assess graft perfusion in 150 consecutive patients undergoing esophagectomy with planned GPU reconstruction. An esophagogastric anastomosis was performed in 144 patients. A leak was found in 24 patients (16.7%) and were significantly less likely when the anastomosis was placed in an area of good perfusion compared with when the anastomosis was placed in an area of less robust perfusion by LAA (2% vs 45%, P < 0.0001). By multivariate analysis perfusion at the site of the anastomosis was the only significant factor associated with a leak. Intraoperative real-time assessment of perfusion with LAA correlated with the likelihood of an anastomotic leak and confirmed the critical relationship between good perfusion and anastomotic healing. The use of LAA may contribute to reduced anastomotic morbidity.

351. Gene Electrotransfer of pVEGF in a Porcine Model to Induce Angiogenesis and Improve Cardiac Function

Nonviral gene therapy is an attractive method for treating cardiovascular disease; however, achieving appropriate gene expression levels is often problematic. Gene electro transfer (GET) can be safely used to enhance expression. We have previously reported on establishing GET protocols to safely and effectively delivering plasmids encoding luciferase, green fluorescent protein or VEGFA directly to the heart in a porcine model. In the current study, we tested whether gene delivery of VEGF via GET could induce angiogenesis and improve cardiac function in a porcine ischemic model. Domestic farm pigs were anesthetized and intubated followed by median sternotomy to expose the heart. The left anterior descending coronary artery was partially tied off to induce localized ischemia. Animals received no treatment, injection of pVEGF or injection of pVEGF with electro transfer. Treatment was performed at four sites surrounding the ischemic region on the border of viable and ischemic myocardium. A SPY Intraoperative Perfusion Assessment System was utilized to determine the area of ischemia and quantify the approximate reduction in perfusion and to identify the area of ischemia before treatment. The animals were followed for seven weeks. Ultrasound evaluation and arteriograms were performed prior to surgery, post treatment, 2 weeks post treatment and 7 weeks post treatment. Arteriograms suggest the growth of blood vessels as early as 2 weeks. Spy analysis revealed significant increase in perfusion within the ischemic zone in animals treated with pVEGF +GET compared to controls. Echography showed improved cardiac output was significantly greater (p<0.03) 14 days post-infarct in GET treated animals compared to values immediately after surgery. Based on these results, gene delivery to the heart can be successfully accomplished using in vivo GET and evidence suggests the potential for a therapeutic effect.

Anastomotic leakage in rectal cancer surgery: The role of blood perfusion.

Anastomotic leakage after anterior resection for rectal cancer remains a common and often devastating complication. Preoperative risk factors for anastomotic leakage have been studied extensively and are used for patient selection, especially whether to perform a diverting stoma or not. From the current literature, data suggest that perfusion in the rectal stump rather than in the colonic limb may be more important for the integrity of the colorectal anastomosis. Moreover, available research suggests that the mid and upper rectum is considerably more vascularized than the lower part, in which the posterior compartment seems most vulnerable. These data fit neatly with the observation that anastomotic leaks are far more frequent in patients undergoing total compared to partial mesorectal excision, and also that most leaks occur dorsally. Clinical judgment has been shown to ineffectively assess anastomotic viability, while promising methods to measure blood perfusion are evolving. Much interest has recently been turned to near-infrared light technology, enhanced with fluorescent agents, which enables intraoperative perfusion assessment. Preliminary data are promising, but large-scale controlled trials are lacking. With maturation of such technology, perfusion measurements may in the future inform the surgeon whether anastomoses are at risk. In high colorectal anastomoses, anastomotic revision might be feasible, while a diverting stoma could be fashioned selectively instead of routinely for low anastomoses.

Perfusion Assessment in Laparoscopic Left-Sided/Anterior Resection (PILLAR II): A Multi-Institutional Study

Our primary objective was to demonstrate the utility and feasibility of the intraoperative assessment of colon and rectal perfusion using fluorescence angiography (FA) during left-sided colectomy and anterior resection. Anastomotic leak (AL) after colorectal resection increases morbidity, mortality, and, in cancer cases, recurrence rates. Inadequate perfusion may contribute to AL. The PINPOINT Endoscopic Fluorescence Imaging System allows for intraoperative assessment of anastomotic perfusion. This is a prospective, multicenter, open-label, clinical trial that assessed the feasibility and utility of FA for intraoperative perfusion assessment during left-sided colectomy and anterior resection at 11 centers in the United States. A total of 147 patients were enrolled, of whom 139 were eligible for analysis. Diverticulitis (44%), rectal cancer (25%), and colon cancer (21%) were the most prevalent indications for surgery. The mean level of anastomosis was 10 ± 4 cm from the anal verge. Splenic-flexure mobilization was performed in 81% and high ligation of the inferior mesenteric artery in 61.9% of patients. There was a 99% success rate for FA, and FA changed surgical plans in 11 (8%) patients, with the majority of changes occurring at the time of transection of the proximal margin (7%). Overall morbidity rates were 17%. The anastomotic leak rate was 1.4% (n= 2). There were no anastomotic leaks in the 11 patients who had a change in surgical plan based on intraoperative perfusion assessment with FA. PINPOINT is a safe and feasible tool for intraoperative assessment of tissue perfusion during colorectal resection. There were no anastomotic leaks in patients in whom the anastomosis was revised based on inadequate perfusion with FA.

Intraoperative angiography provides objective assessment of skin perfusion in complex knee reconstruction.

Wound necrosis is a potentially devastating complication of complex knee reconstruction. Laser-assisted indocyanine green angiography (LA-ICGA) is a technology that has been described in the plastic surgery literature to provide an objective assessment of skin perfusion in the operating room. This novel technology uses a plasma protein bound dye (ICG) and a camera unit that is calibrated to view the frequency emitted by the dye. The intention of this technology is to offer real-time visualization of blood flow to skin and soft tissue in a way that might help surgeons make decisions about closure or coverage of a surgical site based on blood flow, potentially avoiding soft tissue reconstruction while preventing skin necrosis or wound breakdown after primary closures, but its efficacy is untested in the setting of complex TKA. The purpose of this study was to evaluate perfusion borders and tension ischemia in a series of complex knee reconstructions to guide optimal wound management. Beginning in mid-2011, an LA-ICGA system was used to evaluate soft tissue viability in knee reconstruction procedures that were considered high risk for wound complications. Seven patients undergoing complex primary or revision TKA from 2011 to 2013 were included. These patients were chosen as a convenience sample of knee reconstruction procedures for which we obtained consultation with the plastic surgery service. The perfusion of skin and soft tissue coverage was evaluated intraoperatively for all patients with the LA-ICGA system, and the information was used to guide wound management. Followup was at a mean of 9 months (range, 6-17 months), no patients were lost to followup, and the main study endpoint was uneventful healing of the surgical incision. All seven closures went on to heal without necrosis. One patient, however, was subsequently revised for a deep periprosthetic infection 4 months after their knee reconstruction and underwent flap coverage at the time of that revision. Implementation of LA-ICGA provides an objective intraoperative assessment of soft tissue perfusion. This technology may help guide the surgeon's decisions about wound closure in real-time to accommodate the perfusion challenges unique to each patient. Specifically, patients with medical risk factors for poor perfusion or wound healing (such as diabetes, peripheral vascular disease, tobacco use, corticosteroid therapy, infection) or anatomical/surgical risk factors (ie, previous surgery about the reconstruction site, trauma wounds, or reconstruction of severe deformity) may benefit from objective intraoperative information regarding perfusion of the wound site. Furthermore, LA-ICGA could be used to prospectively evaluate the physiologic impact of different wound closure techniques. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Intraoperative assessment of cortical perfusion by indocyanine green videoangiography in surgical revascularization for moyamoya disease.

Postoperative hyperperfusion is a potential complication of the direct bypass procedure for moyamoya disease (MMD). However, no reliable modality is available yet for the prediction of postoperative hyperperfusion during surgery for MMD. This study aimed to investigate whether semiquantitative analysis of indocyanine green (ICG) videoangiography could contribute to the prediction of postoperative hyperperfusion in MMD. This study included 12 hemispheres from 10 patients who underwent surgical revascularization for MMD. Intraoperative ICG videoangiography was performed before and after a direct bypass procedure. The ICG intensity-time curves were semiquantitatively analyzed to evaluate cortical perfusion by calculating the blood flow index (BFI). Using single-photon emission computed tomography (SPECT), postoperative cerebral blood flow measurements were performed thrice: immediately, and 2 and 7 days after surgery. BFI significantly increased from 21.3 ± 10.5 to 38.4 ± 20.0 after bypass procedures in all the hemispheres (p < 0.01). The ratio of BFI before and after the bypass procedure was 2.4 ± 2.0, ranging from 0.5 to 8.0. Postoperative hyperperfusion was observed in nine of the 12 operated hemispheres within 7 days after surgery. Of these, three hemispheres developed hyperperfusion immediately after surgery. In the adult cases, the increase in the ratio of BFI after bypass was significantly greater in those who developed hyperperfusion immediately after surgery than in those who did not (6.5 ± 0.5 vs. 1.8 ± 2.1, p < 0.01). In contrast, no significant increase in BFI was observed in the pediatric MMD patients who experienced immediate hyperperfusion. No correlation between the changes in BFI and the occurrence of delayed hyperperfusion was observed. Our results suggest that semiquantitative analysis of BFI by intraoperative ICG videoangiography is useful in evaluating changes in cortical perfusion after bypass procedures for MMD and can predict the occurrence of early-onset hyperperfusion in MMD patients after direct bypass.

Racial Differences in Ischemic Complications of Pedicled Versus Free Abdominal Flaps for Breast Reconstruction

This study aims to determine the relationship between race and ischemic complications in women undergoing breast reconstruction with pedicled TRAM (pTRAM) and perforator flaps (DIEP). A retrospective, cross-sectional study of women who underwent breast reconstruction utilizing either pTRAM or DIEP flaps from March 1, 2002 to September 1, 2012 was performed. Clinical and demographic variables, including race and ischemic complications (mastectomy flap necrosis, fat necrosis, partial abdominal flap necrosis, vascular compromise requiring reoperation), were examined. Fat necrosis was graded using a previously established scale (grade I = radiologically visible, II = palpable, III = palpable and visible, IV = symptomatic). Over the 10-year study period, adequate follow-up was available for 138 women (94 Caucasian, 36 African American) who underwent pTRAM or DIEP. Fat necrosis occurred more frequently in the pTRAM group (53.5% vs. 17.4%, P < 0.001). There was no statistically significant difference in partial flap necrosis or mastectomy flap necrosis between the 2 groups. The DIEP group had a higher rate of vascular compromise requiring reoperation (13% vs. 0, P = 0.003). In the pTRAM group, there was a higher rate of fat necrosis (77% vs. 45.6%, P < 0.001) and grade IV fat necrosis in African Americans (42.8% vs. 9.5%, P = 0.005). Rates of other ischemic complications were comparable between the 2 racial groups. In the DIEP group, ischemic complications were comparable between the 2 racial groups. After stratifying by flap type and race, we saw no differences in mastectomy flap necrosis (P = 0.0182). African Americans undergoing pTRAM flap are at higher risk for grade IV fat necrosis but not mastectomy flap necrosis or partial flap necrosis. This may be due to difficulty using physical examination to judge the vascular status of a pedicle flap that is known to undergo significant changes in vascular physiology following transfer. Intraoperative assessment of perfusion using new technologies may be useful in these higher risk patients.

Near Infrared Fluorescence Imaging to Aid in Selective Arterial Clamping

Abstract Introduction: Near infrared fluorescence imaging with indocyanine green (ICG) is an adjunct technology to facilitate intraoperative assessment of renal vascularization and tissue perfusion...

Intraoperative assessment of human spinal cord perfusion using near infrared spectroscopy with indocyanine green tracer technique

Background contextDespite the significant interest in the assessment of human cerebral perfusion, investigations into human spinal cord perfusion (SCP) are scarce. Current intraoperative monitoring of spinal cord relies on the assessment of neural conduction as a surrogate for SCP. However, there are various inherent limitations associated with the use of these techniques. Near infrared spectroscopy (NIRS) has been successfully used for monitoring and assessment of human cerebral perfusion and has shown promising results in intraoperative assessment of SCP in animal models. PurposeThe aim of this study was to investigate whether it is possible to monitor physiological changes in human SCP intraoperatively using NIRS with indocyanine green (ICG) tracer technique. We used this technique to calculate the human spinal cord carbon dioxide (CO2) reactivity index. In addition, we investigated whether the lamina causes significant attenuation of NIRS signals. Study design/settingIntraoperative human experimental study. Patient sampleEighteen patients undergoing elective posterior cervical spine surgery. Outcome measuresCarbon dioxide reactivity of human SCP. MethodsNine patients underwent transdural assessment of SCP, with an additional nine patients undergoing translaminar measurements. Patients' SCP was continuously monitored using an NIRO-500 NIRS monitor via a set of purpose built optodes. Their arterial ICG concentration was simultaneously assessed using a pulse dye densitometer. Patients' end-tidal CO2 was gradually increased by 7.5 mm Hg and then returned back to baseline. Three sets of measurements were taken: baseline, hypercapnic, and return to baseline. ResultsAfter hypercapnia, SCP increased by a mean of 57.2±23.3% in the transdural group and 46.6±36.3% in the translaminar group. Carbon dioxide reactivity index was 7.6±3.2%ΔSCP/mm Hg in the transdural group and 6.4±5.3 %ΔSCP/mm Hg in the translaminar group. There was no significant difference in the increase in SCP (p=.475) or the CO2 reactivity index (p=.581) observed between the transdural and the translaminar groups. ConclusionsIntraoperative NIRS with ICG tracer technique can identify an increase in the SCP in response to hypercapnia. It is possible to use this technique for monitoring SCP over the dura and the lamina. This technique could potentially be used to provide insight in to the pathophysiology and autoregulation of commonly acquired spinal cord conditions. Further research assessing the use of NIRS for monitoring of SCP is required.

Potential of the SPY intraoperative perfusion assessment system to reduce ischemic complications in immediate postmastectomy breast reconstruction

BackgroundThe quality and viability of mastectomy flaps remain a central challenge in reconstructive surgery, particularly for immediate breast reconstruction. Insufficient perfusion in tissue flaps is a leading cause of early complications following reconstructive procedures, and clinical judgment alone is not completely reliable for the assessment of flap viability. Accurate and reliable intraoperative methods for assessment of tissue perfusion are needed to help surgeons identify tissue at risk for ischemia and necrosis, thereby allowing for maneuvers to improve tissue flap viability.MethodsThis study evaluates the use of intraoperative laser angiography using the SPY System (LifeCell Corp., Branchburg, NJ) for the assessment of perfusion in mastectomy flaps for immediate breast reconstruction. The SPY System uses the contrast agent indocyanine green, which has an excellent safety profile and pharmacokinetics that allow for repeat evaluations during the same surgical procedure. In recent work, the SPY System has demonstrated high sensitivity and specificity for detection of tissues at risk for ischemia and necrosis during reconstructive surgery. Using a retrospective, chart-review design, the authors compared consecutive cases of immediate breast reconstruction using a prosthesis, before and after implementation of the SPY System.ResultsNinety-one subjects were included in the analysis: 52 prior to SPY (Pre-SPY) and 39 after implementation of SPY (Post-SPY). Baseline characteristics were similar between the groups. Both groups had high rates of comorbidities, chemotherapy, and radiation therapy. The rate of postoperative complications was two-fold higher in the Pre-SPY group compared to the Post-SPY group (36.5% vs. 17.9%); this difference was of borderline significance (P = 0.0631). However, mean number of repeat visits to the OR per patient was significantly higher in the Pre-SPY group (1.21 ± 1.47 vs. 0.41 ± 0.71; P = 0.0023). Of the seven patients with complications in the Post-SPY group, five were identified by SPY as having poor flap perfusion; none were identified by clinical judgment alone.ConclusionsThis study suggests that the SPY System can contribute to reduced ischemia-related complications in a population of women undergoing immediate breast reconstruction following mastectomy for breast cancer.

SPY-Q Analysis Toolkit Values Potentially Predict Mastectomy Flap Necrosis

Previously, we and other investigators have reported the benefits of using SPY Intraoperative Perfusion Assessment System to assist in the prediction of mastectomy flap necrosis. To date, analysis of the SPY images has been subjective. However, the new SPY-Q postprocessing software allows for objective quantification of SPY images through the application of absolute and relative values of fluorescence intensity. This study seeks to determine the use of these objective, numerical data and their role in potentially predicting mastectomy flap necrosis. In a retrospective fashion, 20 SPY images from immediate breast reconstructions were randomly selected from a database of more than 100 images: 10 from breasts that developed flap necrosis and 10 from breasts that demonstrated adequate healing. Groups were matched for age, body mass index, and comorbidities. The points of necrosis and points of adequate healing were evaluated using the postprocessing software, and the groups were compared. The mean "relative" fluorescence of the necrosis and the adequate healing groups was 25.2% and 43.3%, respectively (P < 0.001). The mean absolute fluorescence of the 2 groups was 18.5 and 25.0, respectively (P = 0.07). These findings suggest that quantitative "relative" perfusion values as generated by the postprocessing software may augment clinical judgment of flap viability in an objective and reproducible fashion.

Bone flap perfusion assessment using near-infrared fluorescence imaging

BackgroundMicrosurgical vascularized bone flaps are a versatile technique for reconstructing large bone defects. However, the assessment of perfusion is challenging, because clinical examination is difficult intraoperatively and often not possible postoperatively. Therefore, it is important to develop techniques to assess the perfusion of vascularized bone flaps and potentially improve the surgical outcomes. Near-infrared (NIR) fluorescence imaging has previously been shown to provide real-time, intraoperative evaluation of vascular perfusion. The present pilot study investigated the ability of NIR imaging to assess the perfusion of vascularized bone flaps. MethodsVascularized bone flaps were created in female Yorkshire pigs using well-established models for porcine forelimb osteomyocutaneous flap allotransplantation (n = 8) and hindlimb fibula flaps (n = 8). Imaging of the bone flaps was performed during harvest using the FLARE intraoperative fluorescence imaging system after systemic injection of indocyanine green. Perfusion was also assessed using the standard of care by clinical observation and Doppler ultrasonography. NIR fluorescence perfusion assessment was confirmed by intermittent clamping of the vascular pedicle. ResultsNIR fluorescence imaging could identify bone perfusion at the cut end of the osteotomy site. When the vascular pedicle was clamped or ligated, NIR imaging demonstrated no fluorescence when injected with indocyanine green. With clamp removal, the osteotomy site emitted fluorescence, indicating bone perfusion. The results using fluorescence imaging showed 100% agreement with the clinical observation and Doppler findings. ConclusionsVascularized bone transfers have become an important tool in reconstructive surgery; however, no established techniques are available to adequately assess perfusion. The results of our pilot study have indicated that NIR imaging can provide real-time, intraoperative assessment of bone perfusion.

Near-Infrared Imaging for Intra-operative Assessment of Perfusion in Vascularized Bone Flaps

Near-Infrared Imaging for Intra-operative Assessment of Perfusion in Vascularized Bone Flaps

Bone graft scintigraphy

Summary Aim: To evaluate a scintigraphic tool for intra - operative assessment of vascularized bone graft perfusion before and after transplantation. Patients, methods: This pilot study included three patients scheduled for surgical segmental mandibulectomy followed by reconstruction with a vascularized iliac bone graft. A continuous 99mTc-pertechnetate infusion was applied selectively arterial into the blood vessel supplying the respective graft before osteotomy as well as after transplantation. Perfusion was analysed by scintigrams acquired using the intraoperative camera systems declipseSPECT and Sentinella. Results were compared qualitatively. Results: Before harvesting the graft, intraoperative scintigraphy revealed a clearly delineated area of the iliac crest with a relatively homogenous pertechnetate distribution representing good perfusion. After osteotomy, transplantation to the mandibula and re-anastomosis of the nutrient vessels, scintigraphy in all patients showed a moderately inhomogenous distribution pattern of the pertechnetate indicating an adequate perfusion of the bone transplant through the arterial anastomosis. Conclusion: Intraoperative assessment of bone graft perfusion is possible with the imaging systems Sentinella as well as with declipse SPECT using a continuous intra-arterial infusion of 99mTc-pertechnetate.