Near-infrared fluorescence image-guidance in plastic surgery: A systematic review

Systematic review and meta-analysis on macrovascular and microvascular anatomy of preputial skin in hypospadias and its implications

INTRODUCTION

Hypospadias repair is challenging due to complications like urethrocutaneous fistula and flap necrosis, often linked to preputial vascular anatomy. While macrovascular and microvascular patterns are studied, findings are inconsistent. The impact of preoperative hormonal therapy (PHT) on vascularity and outcomes is unclear. This review and meta-analysis evaluates preputial vascular anatomy in hypospadias and its surgical implications.

METHODS

A systematic review (2000-2024) was conducted in PubMed, MEDLINE, and Cochrane following PRISMA guidelines. The inclusion criteria used the PICOS framework. The bias was assessed using Robvis and microvessel density (MVD) differences were analyzed via meta-analysis with heterogeneity quantified (I2). Effects of PHT on vascularity were also reviewed.

RESULTS

Fourteen studies (707 hypospadias, 106 controls) revealed predominant net-like vascular patterns in severe cases. MVD was significantly lower in hypospadias (pooled Mean, 28.85/HPF) versus controls (pooled Mean, 45.46/HPF), correlating with severity of hypospadias, the MVD varied a lot across different population worldwide. The meta-analysis showed high heterogeneity (I2 = 98%). PHT increased MVD and vessel diameter, improving outcomes in three studies.

CONCLUSION

Hypospadias alters preputial vascular anatomy, show varied patterns, with reduced MVD linked to surgical challenges. A lot of variation exist in MVD across various population. PHT enhances vascularity but requires further validation. Standardized vascular assessments and advanced imaging are essential for optimizing surgical outcomes. PROSPERO registration number CRD42025640297.

Synthesis and evaluation of a novel BODIPY fluorescent probe targeting integrin αvβ3 for cancer diagnosis

A series of integrin αvβ3 targeting BODIPY-RGD conjugate were designed and synthesized. Their in vitro and in vivo fluorescence imaging behaviors were investigated. The small molecule compound was designed as an optical imaging near-infrared fluorescent dye which was combined RGD peptide with the meso-amide BODIPYs using succinic moiety as a spacer. The construction alleviated the traditional BODIPY problems including poor water solubility, aggregate caused quench (ACQ) effect, low biocompatibility, etc. In cellular research, BDP-RGD-2 showed rapid, selective uptake in 3 highly expressing integrin αvβ3 cell lines MDA-MB-231, A549, U87MG at different extent rather than an integrin αvβ3 low level expression cell MCF-7. In animal study, fluorescence imaging of U87MG model targeted by BDP-RGD-2 displayed a highest tumor uptake level and T/N ratio up to 6 h after tail-intravenous injection, which demonstrated BDP-RGD-2 was a promising probe for tracing integrin αvβ3 overexpressing tumors.

eTFC-01: a dual-labeled chelate-bridged tracer for SSTR2-positive tumors

BACKGROUND

Integrating radioactive and optical imaging techniques can facilitate the prognosis and surgical guidance for cancer patients. Using a single dual-labeled tracer ensures consistency in both imaging modalities. However, developing such molecule is challenging due to the need to preserve the biochemical properties of the tracer while introducing bulky labeling moieties. In our study, we designed a trifunctional chelate that facilitates the coupling of the targeting vector and fluorescent dye at opposite sites to avoid undesired steric hindrance effects. The synthesis of the trifunctional chelate N3-Py-DOTAGA-(tBu)3 (7) involved a five-step synthetic route, followed by conjugation to the linear peptidyl-resin 8 through solid-phase synthesis. After deprotection and cyclization, the near-infrared fluorescent dye sulfo-Cy.5 was introduced using copper free click chemistry, resulting in eTFC-01. Subsequently, eTFC-01 was labeled with [111In]InCl3. In vitro assessments of eTFC-01 binding, uptake, and internalization were conducted in SSTR2-transfected U2OS cells. Ex-vivo biodistribution and fluorescence imaging were performed in H69-tumor bearing mice.

RESULTS

eTFC-01 demonstrated a two-fold higher IC50 value for SSTR2 compared to the gold standard DOTA-TATE. Labeling of eTFC-01 with [111In]InCl3 gave a high radiochemical yield and purity. The uptake of [111In]In-eTFC-01 in U2OS.SSTR2 cells was two-fold lower than the uptake of [111In]In-DOTA-TATE, consistent with the binding affinity. Tumor uptake in H69-xenografted mice was lower for [111In]In-eTFC-01 at all-time points compared to [111In]In-DOTA-TATE. Prolonged blood circulation led to increased accumulation of [111In]In-eTFC-01 in highly vascularized tissues, such as lungs, skin, and heart. Fluorescence measurements in different organs correlated with the radioactive signal distribution.

CONCLUSION

The successful synthesis and coupling of the trifunctional chelate to the peptide and fluorescent dye support the potential of this synthetic approach to generate dual labeled tracers. While promising in vitro, the in vivo results obtained with [111In]In-eTFC-01 suggest the need for adjustments to enhance tracer distribution.

Geotemporal Fluorophore Biodistribution Mapping of Colorectal Cancer: Micro and Macroscopic Insights

Fluorescence-guided oncology promises to improve both the detection and treatment of malignancy. We sought to investigate the temporal distribution of indocyanine green (ICG), an exogenous fluorophore in human colorectal cancer. This analysis aims to enhance our understanding of ICG's effectiveness in current tumour detection and inform potential future diagnostic and therapeutic enhancements.

METHODS

Fifty consenting patients undergoing treatment for suspected/confirmed colorectal neoplasia provided near infrared (NIR) video and imagery of transanally recorded and ex vivo resected rectal lesions following intravenous ICG administration (0.25 mg/kg), with a subgroup providing tissue samples for microscopic (including near infrared) analysis. Computer vision techniques detailed macroscopic 'early' (<15 min post ICG administration) and 'late' (>2 h) tissue fluorescence appearances from surgical imagery with digital NIR scanning (Licor, Lincoln, NE, USA) and from microscopic analysis (Nikon, Tokyo, Japan) undertaken by a consultant pathologist detailing tissue-level fluorescence distribution over the same time.

RESULTS

Significant intra-tumoural fluorescence heterogeneity was seen 'early' in malignant versus benign lesions. In all 'early' samples, fluorescence was predominantly within the tissue stroma, with uptake within plasma cells, blood vessels and lymphatics, but not within malignant or healthy glands. At 'late' stage observation, fluorescence was visualised non-uniformly within the intracellular cytoplasm of malignant tissue but not retained in benign glands. Fluorescence also accumulated within any present peritumoural inflammatory tissue.

CONCLUSION

This study demonstrates the time course diffusion patterns of ICG through both benign and malignant tumours in vivo in human patients at both macroscopic and microscopic levels, demonstrating important cellular drivers and features of geolocalisation and how they differ longitudinally after exposure to ICG.

Biliary Anatomy Visualization and Surgeon Satisfaction Using Standard Cholangiography versus Indocyanine Green Fluorescent Cholangiography during Elective Laparoscopic Cholecystectomy: A Randomized Controlled Trial

Background: Intraoperative biliary anatomy recognition is crucial for safety during laparoscopic cholecystectomy, since iatrogenic bile duct injuries represent a fatal complication, occurring in up to 0.9% of patients. Indocyanine green fluorescence cholangiography (ICG-FC) is a safe and cost-effective procedure for achieving a critical view of safety and recognizing early biliary injuries. The aim of this study is to compare the perioperative outcomes, usefulness and safety of standard intraoperative cholangiography (IOC) with ICG-FC with intravenous ICG. Methods: Between 1 June 2021 and 31 December 2022, 160 patients undergoing elective LC were randomized into two equal groups: Group A (standard IOC) and group B (ICG-FC with intravenous ICG). Results: No significant difference was found between the two groups regarding demographics, surgery indication or surgery duration. No significant difference was found regarding the visualization of critical biliary structures. However, the surgeon satisfaction and cholangiography duration presented significant differences in favor of ICG-FC. Regarding the inflammatory response, a significant difference between the two groups was found only in postoperative WBC levels. Hepatic and renal function test results were not significantly different between the two groups on the first postoperative day, except for direct bilirubin. No statistically significant difference was noted regarding 30-day postoperative complications, while none of the complications noted included bile duct injury events. Conclusions: ICG-FC presents equivalent results to IOC regarding extrahepatic biliary visualization and postoperative complications. However, more studies need to be performed in order to standardize the optimal dose, timing and mode of administration.

Photoacoustic imaging on its way toward clinical utility: a tutorial review focusing on practical application in medicine

Significance

Photoacoustic imaging (PAI) enables the visualization of optical contrast with ultrasonic imaging. It is a field of intense research, with great promise for clinical application. Understanding the principles of PAI is important for engineering research and image interpretation.

Aim

In this tutorial review, we lay out the imaging physics, instrumentation requirements, standardization, and some practical examples for (junior) researchers, who have an interest in developing PAI systems and applications for clinical translation or applying PAI in clinical research.

Approach

We discuss PAI principles and implementation in a shared context, emphasizing technical solutions that are amenable to broad clinical deployment, considering factors such as robustness, mobility, and cost in addition to image quality and quantification.

Results

Photoacoustics, capitalizing on endogenous contrast or administered contrast agents that are approved for human use, yields highly informative images in clinical settings, which can support diagnosis and interventions in the future.

Conclusion

PAI offers unique image contrast that has been demonstrated in a broad set of clinical scenarios. The transition of PAI from a "nice-to-have" to a "need-to-have" modality will require dedicated clinical studies that evaluate therapeutic decision-making based on PAI and consideration of the actual value for patients and clinicians, compared with the associated cost.

Microsurgery Robots: Applications, Design, and Development

Microsurgical techniques have been widely utilized in various surgical specialties, such as ophthalmology, neurosurgery, and otolaryngology, which require intricate and precise surgical tool manipulation on a small scale. In microsurgery, operations on delicate vessels or tissues require high standards in surgeons' skills. This exceptionally high requirement in skills leads to a steep learning curve and lengthy training before the surgeons can perform microsurgical procedures with quality outcomes. The microsurgery robot (MSR), which can improve surgeons' operation skills through various functions, has received extensive research attention in the past three decades. There have been many review papers summarizing the research on MSR for specific surgical specialties. However, an in-depth review of the relevant technologies used in MSR systems is limited in the literature. This review details the technical challenges in microsurgery, and systematically summarizes the key technologies in MSR with a developmental perspective from the basic structural mechanism design, to the perception and human-machine interaction methods, and further to the ability in achieving a certain level of autonomy. By presenting and comparing the methods and technologies in this cutting-edge research, this paper aims to provide readers with a comprehensive understanding of the current state of MSR research and identify potential directions for future development in MSR.

Optical absorption spectra and corresponding in vivo photoacoustic visualization of exposed peripheral nerves

Significance

Multispectral photoacoustic imaging has the potential to identify lipid-rich, myelinated nerve tissue in an interventional or surgical setting (e.g., to guide intraoperative decisions when exposing a nerve during reconstructive surgery by limiting operations to nerves needing repair, with no impact to healthy or regenerating nerves). Lipids have two optical absorption peaks within the NIR-II and NIR-III windows (i.e., 1000 to 1350 nm and 1550 to 1870 nm wavelength ranges, respectively) which can be exploited to obtain photoacoustic images. However, nerve visualization within the NIR-III window is more desirable due to higher lipid absorption peaks and a corresponding valley in the optical absorption of water.

Aim

We present the first known optical absorption characterizations, photoacoustic spectral demonstrations, and histological validations to support in vivo photoacoustic nerve imaging in the NIR-III window.

Approach

Four in vivo swine peripheral nerves were excised, and the optical absorption spectra of these fresh ex vivo nerves were characterized at wavelengths spanning 800 to 1880 nm, to provide the first known nerve optical absorbance spectra and to enable photoacoustic amplitude spectra characterization with the most optimal wavelength range. Prior to excision, the latter two of the four nerves were surrounded by aqueous, lipid-free, agarose blocks (i.e., 3% w/v agarose) to enhance acoustic coupling during in vivo multispectral photoacoustic imaging using the optimal NIR-III wavelengths (i.e., 1630 to 1850 nm) identified in the ex vivo studies.

Results

There was a verified characteristic lipid absorption peak at 1725 nm for each ex vivo nerve. Results additionally suggest that the 1630 to 1850 nm wavelength range can successfully visualize and differentiate lipid-rich nerves from surrounding water-containing and lipid-deficient tissues and materials.

Conclusions

Photoacoustic imaging using the optimal wavelengths identified and demonstrated for nerves holds promise for detection of myelination in exposed and isolated nerve tissue during a nerve repair surgery, with possible future implications for other surgeries and other optics-based technologies.

NIR-II Nanoprobes: A Review of Components-Based Approaches to Next-Generation Bioimaging Probes

Fluorescence and photoacoustic imaging techniques offer valuable insights into cell- and tissue-level processes. However, these optical imaging modalities are limited by scattering and absorption in tissue, resulting in the low-depth penetration of imaging. Contrast-enhanced imaging in the near-infrared window improves imaging penetration by taking advantage of reduced autofluorescence and scattering effects. Current contrast agents for fluorescence and photoacoustic imaging face several limitations from photostability and targeting specificity, highlighting the need for a novel imaging probe development. This review covers a broad range of near-infrared fluorescent and photoacoustic contrast agents, including organic dyes, polymers, and metallic nanostructures, focusing on their optical properties and applications in cellular and animal imaging. Similarly, we explore encapsulation and functionalization technologies toward building targeted, nanoscale imaging probes. Bioimaging applications such as angiography, tumor imaging, and the tracking of specific cell types are discussed. This review sheds light on recent advancements in fluorescent and photoacoustic nanoprobes in the near-infrared window. It serves as a valuable resource for researchers working in fields of biomedical imaging and nanotechnology, facilitating the development of innovative nanoprobes for improved diagnostic approaches in preclinical healthcare.

LED-based photoacoustic imaging for preoperative visualization of lymphatic vessels in patients with secondary limb lymphedema

Lymphedema is the accumulation of protein-rich fluid in the interstitium (i.e., dermal backflow (DBF)). Preoperative imaging of the lymphatic vessels is a prerequisite for lymphovenous bypass surgical planning. We investigated the visualization of lymphatic vessels and veins using light-emitting diode (LED)-based photoacoustic imaging (PAI). Indocyanine-green mediated near-infrared fluorescence lymphography (NIRF-L) was done in fifteen patients with secondary limb lymphedema. Photoacoustic images were acquired in locations where lymphatic vessels and DBF were observed with NIRF-L. We demonstrated that LED-based PAI can visualize and differentiate lymphatic vessels and veins even in the presence of DBF. We observed lymphatic and blood vessels up to depths of 8.3 and 8.6 mm, respectively. Superficial lymphatic vessels and veins can be visualized using LED-based PAI even in the presence of DBF showing the potential for pre-operative assessment. Further development of the technique is needed to improve its usability in clinical settings.

Beneficial Impact of "Supercharged" Pectoralis Major Musculocutaneous Flap With Indocyanine Green Angiography on Reconstruction in a Patient at High Risk for Necrosis

Background

The pectoralis major musculocutaneous (PMMC) flap is a versatile and commonly used technique for reconstruction of the head and neck in patients at high risk in free tissue transfer procedures. In this report, a "supercharged" PMMC flap, in which the lateral thoracic artery was cut, preserved, and anastomosed to the cervical vessels, was developed to stabilize blood flow.

Methods

The supercharged PMMC flap was introduced in a patient who was at high risk for partial necrosis of the flap and underwent surgery for reconstruction of the tongue. Intraoperative perfusion monitoring using laser-assisted indocyanine green angiography (ICGA) was also performed to verify the status of blood flow in the flap.

Results

ICGA monitoring of blood flow in the flap revealed instability. Subsequently, a supercharged PMMC flap was applied, which prevented partial necrosis of the flap.

Conclusions

Combined with ICGA, a supercharged PMMC flap contributed to successful reconstruction in a patient at high risk for necrosis of the flap region.

Imaging of the Lymphatic Vessels for Surgical Planning: A Systematic Review

BACKGROUND

Secondary lymphedema is a common complication after surgical or radiotherapeutic cancer treatment. (Micro) surgical intervention such as lymphovenous bypass and vascularized lymph node transfer is a possible solution in patients who are refractory to conventional treatment. Adequate imaging is needed to identify functional lymphatic vessels and nearby veins for surgical planning.

METHODS

A systematic literature search of the Embase, MEDLINE ALL via Ovid, Web of Science Core Collection and Cochrane CENTRAL Register of Trials databases was conducted in February 2022. Studies reporting on lymphatic vessel detection in healthy subjects or secondary lymphedema of the limbs or head and neck were analyzed.

RESULTS

Overall, 129 lymphatic vessel imaging studies were included, and six imaging modalities were identified. The aim of the studies was diagnosis, severity staging, and/or surgical planning.

CONCLUSION

Due to its utility in surgical planning, near-infrared fluorescence lymphangiography (NIRF-L) has gained prominence in recent years relative to lymphoscintigraphy, the current gold standard for diagnosis and severity staging. Magnetic resonance lymphography (MRL) gives three-dimensional detailed information on the location of both lymphatic vessels and veins and the extent of fat hypertrophy; however, MRL is less practical for routine presurgical implementation due to its limited availability and high cost. High frequency ultrasound imaging can provide high resolution imaging of lymphatic vessels but is highly operator-dependent and accurate identification of lymphatic vessels is difficult. Finally, photoacoustic imaging (PAI) is a novel technique for visualization of functional lymphatic vessels and veins. More evidence is needed to evaluate the utility of PAI in surgical planning.

Qualitative features of esophageal fluorescence angiography and anastomotic outcomes in children

BACKGROUND

Indocyanine green (ICG) is commonly used to assess perfusion, but quality defining features are lacking. We sought to establish qualitative features of esophageal ICG perfusion assessments, and develop an esophageal anastomotic scorecard to risk-stratify anastomotic outcomes.

METHODS

Single institution, retrospective analysis of children with an intraoperative ICG perfusion assessment of an esophageal anastomosis. Qualitative perfusion features were defined and a perfusion score developed. Associations between perfusion and clinical features with poor anastomotic outcomes (PAO, leak or refractory stricture) were evaluated with logistic and time-to-event analyses. Combining significant features, we developed and tested an esophageal anastomotic scorecard to stratify PAO risk.

RESULTS

From 2019 to 2021, 53 children (median age 7.4 months) underwent 55 esophageal anastomoses. Median (IQR) follow-up was 14 (10-19.9) months; mean (SD) perfusion score was 13.2 (3.4). Fifteen (27.3%) anastomoses experienced a PAO and had significantly lower mean perfusion scores (11.3 (3.3) vs 14.0 (3.2), p = 0.007). Unique ICG perfusion features, severe tension, and primary or rescue traction-induced esophageal lengthening [Foker] procedures were significantly associated with PAO on both logistic and Cox regression. The scorecard (range 0-7) included any Foker (+2), severe tension (+1), no arborization on either segment (+1), suture line hypoperfusion >twice expected width (+2), and segmental or global areas of hypoperfusion (+1). A scorecard cut-off >3 yielded a sensitivity of 73% and specificity of 93% (AUC 0.878 [95%CI 0.777 to 0.978]) in identifying a PAO.

CONCLUSIONS

A scoring system comprised of qualitative ICG perfusion features, tissue quality, and anastomotic tension can help risk-stratify esophageal anastomotic outcomes accurately.

LEVELS OF EVIDENCE

Diagnostic - II.

Ex Vivo Thrombolysis to Salvage Free Flaps Using Machine Perfusion: A Pilot Study in a Porcine Model

BACKGROUND

 Mechanical evacuation of capillary thrombi in free flaps is difficult, and often requires thrombolytic therapy. Utilizing machine perfusion systems, the possibility rises to salvage free flaps ex vivo by administering high doses of thrombolytic agents. The primary aim of this pilot study in a porcine model is to investigate the feasibility of ex vivo thrombolysis using an extracorporeal perfusion machine.

METHODS

 A model of stasis-induced thrombosis was used in 12 free rectus abdominis flaps harvested from six Dutch Landrace pigs. Compromised flaps were ex vivo perfused with University of Wisconsin preservation solution and treated according to the following study groups: (1) 1 mg of tissue plasminogen activator (t-PA) as additive, (2) 3 mg of t-PA as an additive, and (3) no thrombolytic additive. Microcirculation was assessed using near-infrared fluorescence angiography.

RESULTS

 Pedicled abdominal flaps were created and thrombus formation was successfully induced. Eleven abdominal flaps were perfused using the modified heart-lung machine setup. Near-infrared fluorescence angiography showed delayed or no filling was noted in the control group. In comparison, the flaps which were perfused with 1 mg t-PA or 3 mg t-PA as additive showed increased fluorescence intensity curves.

CONCLUSION

 This pilot study in a porcine model presents a reliable and reproductive stasis-induced thrombosis model in free flaps. By adding t-PA to a custom-made extracorporeal perfusion system, the indocyanine green fluorescence intensity curves increased of all flaps that were perfused with different dosages of t-PA as additives, indicating restoration of capillary pressure and microcirculatory inflow.

Intraoperative uses of near-infrared fluorescence spectroscopy in pediatric surgery: A systematic review

BACKGROUND

The application of near infrared spectroscopy (NIRS) imaging in surgery is growing. This study aimed to systematically review the literature to summarize the intraoperative uses of NIRS in pediatric surgery.

METHODS

A PRISMA-compliant literature search was conducted in PubMed, Embase, Scopus, and Web of Science from inception to February 2020. Title/abstract and then full-text screening were performed. The Oxford centre for Evidence Based Medicine tool (OCEBM) was used to evaluate the level of evidence of included studies.

RESULTS

Reviewers identified 53 articles. Of which, 34 studies (64.2%) were case-series and 11 (20.8%) were case reports. Most of the studies (n = 45, 84.9%) were level 4 on the OCEBM tool. The most common uses of NIRS were to visualize the biliary tree and to identify primary and metastatic malignant tissues. Other applications include assessment of perfusion of tissues including bowel anastomoses, and lymphatic surgery. Several advantages of the introduction of NIRS in pediatric surgery exist including having the potential to reduce operative time and intra/post-operative complications. Moreover, NIRS helps in detecting malignant tissues that can be missed by conventional imaging. However, NIRS has important limitations such as difficulty in identification of the biliary tree in obese patients or inflamed gallbladder, detection of small deeply localized malignant tissues, as well as the high cost.

CONCLUSIONS

NIRS is a promising modality that can be used intraoperatively to augment different pediatric surgical procedures. NIRS has important advantages and limitations compared to conventional surgery, however, more studies are required to evaluate its outcomes and cost-effectiveness.

LEVEL OF EVIDENCE

IV.

Use of Microscope-Integrated Near-Infrared Fluorescence for Enhancing Deep Lymphatic Vessel Detection during Supermicrosurgical Lymphaticovenous Anastomosis: A Longitudinal Cohort Study

BACKGROUND

The default setting of microscope-integrated near-infrared fluorescence (MINIRF) using indocyanine green for locating superficial lymphatic vessels during lymphaticovenous anastomosis was limited to less than or equal to 70 percent intensity. The authors investigated whether maximizing the MINIRF intensity setting could increase the number of deep lymphatic vessels being found, thereby increasing the total number of lymphatic vessels for lymphaticovenous anastomosis.

METHODS

This longitudinal cohort study enrolled 94 patients (86 female and eight male patients) with lower limb lymphedema. Superficial lymphatic vessels were identified with the MINIRF default setting, before maximal intensity was used for deep lymphatic vessel detection. Primary/secondary endpoints included the number of superficial and deep lymphatic vessels identified. No control was used. Demographic data, intraoperative findings [including superficial and deep (indocyanine green-enhanced and non-indocyanine green-enhanced) lymphatic vessels], and severity of lymphosclerosis were recorded. Data in three regions of the lower limb (i.e., foot/above ankle, below knee, and thigh) were compared.

RESULTS

A total of 481 lymphatic vessels were identified, comprising 260 superficial and 221 deep lymphatic vessels. The median number of lymphatic vessels found per patient was five (interquartile range, four to six), and the median lymphatic vessel size was 0.63 mm (interquartile range, 0.5 to 0.8 mm). No difference was found in number (p = 0.360), size (p = 0.215), or severity of lymphosclerosis (p = 0.226) between the overall superficial and deep lymphatic vessels in the three lower limb regions.

CONCLUSIONS

Deep lymphatic vessel detection can be aided by maximizing MINIRF intensity. These deep lymphatic vessels are comparable to superficial lymphatic vessels in number, size, and functionality, making them potentially valuable for lymphedema improvement.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, II.

The Impact of Indocyanine Green Angiography on Fat Necrosis in Deep Inferior Epigastric Perforator Flap Breast Reconstruction

BACKGROUND

The deep inferior epigastric perforator flap (DIEP) is a widely known reliable option for autologous breast reconstruction. One common complication of DIEP procedures is fat necrosis. Consequences of fat necrosis include wound healing complications, pain, infection, and the psychological distress of possible cancerous recurrence. Clinical judgment alone is an imperfect method to detect at-risk segments of adipose tissue. Objective methods to assess perfusion may improve fat necrosis complication rates, reducing additional surgeries to exclude cancer and improve cosmesis for patients.

METHODS

The authors performed a retrospective review of patients who underwent analysis of DIEP flap vascularity with or without intraoperative indocyanine green angiography (ICGA). Flap perfusion was assessed using intravenous ICGA and was quantified with both relative and absolute value units of fluorescence. Tissue with observed values less than 25% to 30% relative value units was resected. Postoperative outcomes and fat necrosis incidence were collected.

RESULTS

Three hundred fifty-five DIEP flaps were included in the study, 187 (52.7%) of which were assessed intraoperatively with ICGA. Thirty-nine patients (10.9%) experienced operable fat necrosis. No statistically significant difference in incidence of postoperative fat necrosis was found between the 2 groups (P = 0.732). However, a statistically significant relationship was found between fat necrosis incidence and body mass index as both a continuum (P = 0.001) and when categorized as greater than 35 (P = 0.038).

CONCLUSIONS

Although ICGA is useful for a variety of plastic surgery procedures, our retrospective review did not show a reduction in operable fat necrosis when using this technology.

Near-Infrared Fluorescence with Indocyanine Green to Assess Bone Perfusion: A Systematic Review

Background: Adequate perfusion of a bone flap is essential for successful reconstruction of osseous defects. Unfortunately, complications related to inadequate bone perfusion are common. Near-infrared fluorescence (NIRF) imaging enables intraoperative visualization of perfusion. NIRF has been investigated in reconstructive surgery to aid the surgeon in clinical perioperative assessment of soft tissue perfusion. However, little is known on the beneficial use of NIRF to assess bone perfusion. Therefore, the aim of this review was to search for studies evaluating NIRF to assess bone perfusion. Methods: A systematic review, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline, was performed. Studies up to October 2021 were included. We extracted data regarding the study population, size and design, reported objective fluorescence parameters and the methodology used for fluorescence imaging and processing. Results: Ten articles were included. Studies reported unevenly on the protocol used for NIRF imaging. Five studies reported objective parameters. Absolute and relative perfusion parameters and parameters derived from maximum fluorescence were reported. The clinical significance of these parameters has not been evaluated in humans. Conclusion: The evidence on bone perfusion as measured with NIRF is limited. More clinical studies are required.

One-Year Outcomes of the First Human Trial on Robot-Assisted Lymphaticovenous Anastomosis for Breast Cancer-Related Lymphedema

BACKGROUND

Lymphaticovenous anastomosis, a supermicrosurgical technique, creates bypasses between the lymphatic and venous systems. The quality of lymphaticovenous anastomosis depends on the surgeon's dexterity and precision, and is subject to imperfections caused by the physiologic tremor of the human hand. A dedicated robot for microsurgery has been created to overcome these limitations (MUSA, MicroSure, Eindhoven, The Netherlands). This study describes 1-year clinical outcomes of the first-in-human trial of robot-assisted and manual lymphaticovenous anastomosis in patients with breast cancer-related lymphedema.

METHODS

In this prospective pilot study, women with breast cancer-related lymphedema were randomized into the robot-assisted or manual lymphaticovenous anastomosis group. Outcomes were quality of life, arm circumference, conservative treatment frequency, arm dermal backflow stage, and anastomosis patency.

RESULTS

Twenty women were included, of whom eight underwent robot-assisted lymphaticovenous anastomosis surgery and 12 underwent manual surgery. In both groups, quality of life significantly improved at 12 months (robot-assisted surgery, p = 0.045; manual surgery, p = 0.001). Arm circumference did not decrease (robot-assisted surgery, p = 0.094; manual surgery, p = 0.240). Daily use of compression garments decreased by 61.9 percent (robot-assisted surgery) and 70.2 percent (manual surgery). The frequency of manual lymphatic drainage remained similar compared with baseline. Arm dermal backflow stage was reduced in one patient in the robot-assisted group and in five cases in the manual group. Overall, 76.5 percent of the anastomoses were patent (robot-assisted surgery, 66.6 percent; manual surgery, 81.8 percent).

CONCLUSIONS

After evaluating 1-year follow-up data, this study confirms the feasibility of robot-assisted lymphaticovenous anastomosis surgery. Clinical outcomes were comparable between robot-assisted and manual lymphaticovenous anastomosis. This encourages further research using the new microsurgical robot MUSA for lymphaticovenous anastomosis and other (super)microsurgical procedures.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Aggregation-induced emission luminogens for image-guided surgery in non-human primates

During the past two decades, aggregation-induced emission luminogens (AIEgens) have been intensively exploited for biological and biomedical applications. Although a series of investigations have been performed in non-primate animal models, there is few pilot studies in non-human primate animal models, strongly hindering the clinical translation of AIE luminogens (AIEgens). Herein, we present a systemic and multifaceted demonstration of an optical imaging-guided surgical operation via AIEgens from small animals (e.g., mice and rabbits) to rhesus macaque, the typical non-human primate animal model. Specifically, the folic conjugated-AIE luminogen (folic-AIEgen) generates strong and stable fluorescence for the detection and surgical excision of sentinel lymph nodes (SLNs). Moreover, with the superior tumor/normal tissue ratio and rapid tumor accumulation, folic-AIEgen successfully images and guides the precise resection of invisible cancerous metastases. Taken together, the presented strategies of folic-AIEgen based fluorescence intraoperative imaging and visualization-guided surgery show potential for clinical applications.

Most applications of aggregation-induced emission luminogens (AIEgens) have been limited in small animal models. Here, the authors show the versatility of AIEgens-based imaging-guided surgical operation from small animals to rhesus macaque, in support of the clinical translation of AIEgens.

Leaving the perfusion zones? Individualized flap design in 100 free DIEP and ms-TRAM flaps for autologous breast reconstruction using indocyanine green angiography

BACKGROUND

There is still no consensus regarding the ideal zoning in abdominal-based autologous breast reconstruction using free DIEP or ms-TRAM flaps. In particular, the perfusion pattern of the flap according to the number of perforators used and their location remains controversial. In this study, the perfusion of free DIEP and ms-TRAM flaps is assessed intraoperatively and analyzed with regard to different perfusion patterns.

METHODS

A retrospective analysis of 100 free flaps for breast reconstruction was performed. Following complete flap harvest, we used indocyanine green angiography for perfusion analysis. By applying two different contour levels, DIEP flaps with lateral or medial perforators and ms-TRAM flaps were assessed for their respective perfusion patterns.

RESULTS

No statistically significant differences were found in the size of the perfusion area between the different flap types when applying the contour level of 20% (p >0.05). For the contour level of 30%, however, statistically significant differences were found between DIEP flaps with medially or laterally located perforators (p = 0.038). Laterally or medially located perforators in DIEP flaps showed no significant differences in their ability to cross the midline (contour level 20%, p = 0.068; contour level 30%, p = 0.058).

CONCLUSION

Considering the variability of the perfusion of the abdominal wall and the high sensitivity of indocyanine green angiography for their detection, the abdominal zonings play a minor role. By using intraoperative indocyanine green angiography, a precise and patient-specific free flap surgery for autologous breast reconstruction is possible independent of perforator location.

Perfusion Parameters in Near-Infrared Fluorescence Imaging with Indocyanine Green: A Systematic Review of the Literature

(1) Background: Near-infrared fluorescence imaging is a technique capable of assessing tissue perfusion and has been adopted in various fields including plastic surgery, vascular surgery, coronary arterial disease, and gastrointestinal surgery. While the usefulness of this technique has been broadly explored, there is a large variety in the calculation of perfusion parameters. In this systematic review, we aim to provide a detailed overview of current perfusion parameters, and determine the perfusion parameters with the most potential for application in near-infrared fluorescence imaging. (2) Methods: A comprehensive search of the literature was performed in Pubmed, Embase, Medline, and Cochrane Review. We included all clinical studies referencing near-infrared perfusion parameters. (3) Results: A total of 1511 articles were found, of which, 113 were suitable for review, with a final selection of 59 articles. Near-infrared fluorescence imaging parameters are heterogeneous in their correlation to perfusion. Time-related parameters appear superior to absolute intensity parameters in a clinical setting. (4) Conclusions: This literature review demonstrates the variety of parameters selected for the quantification of perfusion in near-infrared fluorescence imaging.

The role of near-infrared fluorescence imaging with indocyanine green dye in pedicle division with the paramedian forehead flap

The paramedian forehead flap is considered the gold standard for nasal reconstruction following oncologic surgery. During the 21-day delay in two-stage surgery protocols, many patients report considerably reduced quality of life because of the pedicle. This prospective case series study examined the usefulness of near-infrared (NIR) fluorescence with indocyanine green (ICG) for flap perfusion assessment and identified variables associated with time to flap perfusion. Ten patients (mean age 75.3 ± 11.6 years) with diagnosis of basal cell carcinoma (n = 9) or squamous cell carcinoma (n = 1) underwent intravenous indocyanine injection and NIR fluorescence imaging for assessment of flap vascularisation 2 to 3 weeks after stage 1 surgery. NIR fluorescence imaging showed 90% to 100% perfusion areas in all patients after 14 to 21 days. Early pedicle division occurred in two patients on postoperative days 14 and 16. One minor complication (wound healing disorder) was seen following flap takedown after 14 days. There were no associations between time to flap perfusion and defect size or flap area. NIR fluorescence imaging with ICG dye is a useful method for non-invasive perfusion assessment when used in conjunction with clinical assessment criteria. However, a decision for early pedicle division may raise risk of complications in specific patient groups and must therefore be made with great care.

The use of near infrared fluorescence imaging with indocyanine green for vascular visualization in caudal auricular flaps in two cats

OBJECTIVES

To describe the use of near infrared fluorescence (NIRF) imaging with indocyanine green (ICG) for vascular visualization in two caudal auricular axial pattern flaps (APF).

ANIMALS

Two client-owned cats with upper eyelid masses.

STUDY DESIGN

Clinical case report.

METHODS

Wide surgical excision with enucleation was performed by using a caudal auricular APF for closure. Flap margins and perforating artery location were approximated with anatomical landmarks. The caudal auricular artery origin was then visualized percutaneously by using an exoscope with NIRF camera and light source after a single 2.5-mg dose of IV ICG. Margins were adjusted as required. The flaps were routinely elevated with continued intraoperative visualization of the artery and rotated to complete closure.

RESULTS

After IV ICG administration, fluorescence was initially visualized after 15 to 18 seconds and remained visible for up to 26 minutes. The achieved visualization led to flap margin adjustments in cat 1. Both cats recovered with minimal flap congestion, excellent hair regrowth, and no long-term complications (>186 days). Cat 1 experienced 100% flap survival. Cat 2 experienced 10% partial thickness flap necrosis, but revision was not required, and the flap was healed at recheck 85 days postoperatively.

CONCLUSION

The use of ICG for APF vessel visualization prior to and during flap elevation resulted in transcutaneous visualization of the perforating vessel and improved awareness of vessel location intraoperatively. These two cats experienced excellent flap survival without major complications. This report highlights the potential benefits of ICG NIRF in APF for animals undergoing reconstructive surgery.

Accuracy of infrared thermography for perforator mapping: A systematic review and meta-analysis of diagnostic studies

INTRODUCTION

Infrared thermography allows the detection of infrared radiation which can be reliably associated with skin temperature. Modern portable thermography devices have been used to identify the location of skin perforators by detecting subtle differences in skin temperature. The aim of this study is to conduct a diagnostic accuracy systematic review to determine the specificity and sensitivity of infrared thermography.

MATERIALS AND METHODS

A PRISMA-compliant systematic review and meta-analysis was conducted, scrutinising PUBMED and EMBASE databases for diagnostic studies measuring the accuracy of infrared thermography for perforator identification. Article screening, review and data gathering was conducted in parallel by two independent authors. Eligible studies were subject to a formal risk of bias was assessment using the QUADAS2 instrument.

RESULTS

A total of 254 entries were obtained, of which 7 satisfied our pre-established inclusion criteria. These studies reported a total of 435 perforators in 133 individuals. The most commonly investigated locations were the antero-lateral thigh and abdominal wall. Reported sensitivity values ranged from 73.7% to 100%. A meta-analysis demonstrated a cumulative sensitivity of 95%. Specificity was not routinely reported. All studies presented a moderate to high risk of bias according to QUADAS2.

DISCUSSION

Affordable infrared thermography devices are an interesting alternative to traditional preoperative investigations for perforator mapping. They are sensitive enough to reliably identify a large proportion of perforators as "hot-spots". However, there is limited evidence to estimate the specificity of this technology, as studies have failed to report true negative values associated with "cold-spots".

Imaging Inflammation - From Whole Body Imaging to Cellular Resolution

Imaging techniques have evolved impressively lately, allowing whole new concepts like multimodal imaging, personal medicine, theranostic therapies, and molecular imaging to increase general awareness of possiblities of imaging to medicine field. Here, we have collected the selected (3D) imaging modalities and evaluated the recent findings on preclinical and clinical inflammation imaging. The focus has been on the feasibility of imaging to aid in inflammation precision medicine, and the key challenges and opportunities of the imaging modalities are presented. Some examples of the current usage in clinics/close to clinics have been brought out as an example. This review evaluates the future prospects of the imaging technologies for clinical applications in precision medicine from the pre-clinical development point of view.

Outcomes following lymphaticovenous anastomosis (LVA) for 100 cases of lymphedema: results over 24-months follow-up

PURPOSE

Lymphedema is a debilitating condition that significantly affects patient's quality of life (QoL). The aim of this study was to assess the long-term outcomes after lymphaticovenous anastomosis (LVA) for extremity lymphedema.

METHODS

A single-center prospective study on upper and lower extremity lymphedema patients was performed. All LVA procedures were preceded by outpatient Indocyanine Green (ICG) lymphography. Quality of life measured by the Lymph-ICF was the primary outcome. Limb circumference, use of compression garments, and frequency of cellulitis episodes and manual lymphatic drainage (MLD) sessions were secondary outcomes.

RESULTS

One hundred consecutive patients, predominantly experiencing upper extremity lymphedema following breast cancer (n = 85), underwent a total of 132 LVAs. During a mean follow-up of 25 months, mean Lymph-ICF score significantly decreased from 43.9 preoperative to 30.6 postoperative, representing significant QoL improvement. Decrease in upper and lower limb circumference was observed in 52% of patients with a mean decrease of 6%. Overall mean circumference was not significantly different. Percentage of patients that could reduce compression garments in the upper and lower extremity group was 65% and 40%, respectively. Number of cellulitis episodes per year and MLD sessions per week showed a mean decrease of respectively 0.6 and 0.8 in the upper extremity and 0.4 and 1.0 in the lower extremity group.

CONCLUSIONS

LVA resulted in significant QoL improvement in upper and lower extremity lymphedema patients. Limb circumference did not significantly improve but good results concerning compression garments, cellulitis episodes, and MLD sessions were obtained. Additionally, a simple and patient-friendly method for outpatient ICG lymphography is presented.

Application of imaging in lymphedema surgical therapies

Lymphedema is a chronic, progressive disease caused by primary or secondary reasons. It is currently uncurable and conservative compression therapy is generally applied. Lymphovenous anastomosis and vascularized lymph node transfer (VLNT) are two main surgical treatment that are used in addition to conservative therapy. Lymphovenous anastomosis involves the anastomosing remaining functional lymphatic vessels to vein. When the lymphatic vessels are greatly damaged and in no case can they be used for anastomosis, VLNT provide the affected area with lymph nodes from elsewhere to restore the drainage function. During all these procedures, a clear image to identify related lymphatic structures and venous vessels can be greatly useful for preoperative planning, intraoperative navigation, and postoperative evaluation. Lymphoscintigraphy used to be the gold standard in evaluating lymphedema and mapping lymphatic systems. But due to the downside of radiation, invasive operation and complication, other modalities are gaining attention. In this article, we reviewed the application of Indocyanine green (ICG) lymphography, ultrasound, magnetic resonance lymphography (MRL), and single-photon emission computed tomography-computed tomography (SPECT-CT) in the field of surgical therapy in lymphedema.

Indocyanine green angiography for preventing postoperative mastectomy skin flap necrosis in immediate breast reconstruction

BACKGROUND

Breast cancer will affect one in eight women during their lifetime. The opportunity to restore the removed tissue and cosmetic appearance is provided by reconstructive breast surgery following skin-sparing mastectomy (SSM). Mastectomy skin flap necrosis (MSFN) is a common complication following SSM breast reconstruction. This postoperative complication can be prevented by intraoperative assessment of mastectomy skin flap viability and intervention when tissue perfusion is compromised. Indocyanine green fluorescence angiography is presumed to be a better predictor of MSFN compared to clinical evaluation alone.

OBJECTIVES

To assess the effects of indocyanine green fluorescence angiography (ICGA) for preventing mastectomy skin flap necrosis in women undergoing immediate breast reconstruction following skin-sparing mastectomy. To summarise the different ICGA protocols available for assessment of mastectomy skin flap perfusion in women undergoing immediate breast reconstructions following skin-sparing mastectomy.

SEARCH METHODS

We searched the Cochrane Breast Cancer Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL; Issue 3, 2019), MEDLINE, Embase, the World Health Organization's International Clinical Trials Registry Platform (ICTRP) and Clinicaltrials.gov in April 2019. In addition, we searched reference lists of published studies.

SELECTION CRITERIA

We included studies that compared the use of ICGA to clinical evaluation to assess mastectomy skin vascularisation and recruited women undergoing immediate autologous or prosthetic reconstructive surgery following SSM for confirmed breast malignancy or high risk of developing breast cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias of the included nonrandomised studies and extracted data on postoperative outcomes, including postoperative MSFN, reoperation, autologous flap necrosis, dehiscence, infection, haematoma and seroma, and patient-related outcomes. The quality of the evidence was assessed using the GRADE approach and we constructed two 'Summary of finding's tables: one for the comparison of ICGA to clinical evaluation on a per patient basis and one on a per breast basis.

MAIN RESULTS

Nine nonrandomised cohort studies met the inclusion criteria and involved a total of 1589 women with 2199 breast reconstructions. We included seven retrospective and two prospective cohort studies. Six studies reported the number of MSFN on a per breast basis for a total of 1435 breasts and three studies reported the number of MSFN on a per patient basis for a total of 573 women. Five studies reported the number of other complications on a per breast basis for a total of 1370 breasts and four studies reported the number on a per patient basis for a total of 613 patients. Therefore, we decided to pool data separately. Risk of bias for each included nonrandomised study was assessed using the Newcastle-Ottawa Scale for cohort studies. There was serious concern with risk of bias due to the nonrandomised study design of all included studies and the low comparability of cohorts in most studies. The quality of the evidence was found to be very low, after downgrading the quality of evidence twice for imprecision based on the small sample sizes and low number of events in the included studies. Postoperative complications on a per patient basis We are uncertain about the effect of ICGA on MSFN (RR 0.79, 95% CI 0.40 to 1.56; three studies, 573 participants: very low quality of evidence), infection rates (RR 0.91, 95% CI 0.60 to 1.40; four studies, 613 participants: very low quality of evidence), haematoma rates (RR 0.87, 95% CI 0.30 to 2.53; two studies, 459 participants: very low quality of evidence) and seroma rates (RR 1.68, 95% CI 0.41 to 6.80; two studies, 408 participants: very low quality of evidence) compared to the clinical group. We found evidence that ICGA may reduce reoperation rates (RR 0.50, 95% CI 0.35 to 0.72; four studies, 613 participants: very low quality of evidence). One study considered dehiscence as an outcome. In this single study, dehiscence was observed in 2.2% of participants (4/184) in the ICGA group compared to 0.5% of participants (1/184) in the clinical group (P = 0.372). The RR was 4.00 (95% CI 0.45 to 35.45; one study; 368 participants; very low quality of evidence). Postoperative complications on a per breast basis We found evidence that ICGA may reduce MSFN (RR 0.62, 95% CI 0.48 to 0.82; six studies, 1435 breasts: very low quality of evidence), may reduce reoperation rates (RR 0.65, 95% CI 0.47 to 0.92; five studies, 1370 breasts: very low quality of evidence) and may reduce infection rates (RR 0.65, 95% CI 0.44 to 0.97; five studies, 1370 breasts: very low quality of evidence) compared to the clinical group. We are uncertain about the effect of ICGA on haematoma rates (RR 1.53, CI 95% 0.47 to 4.95; four studies, 1042 breasts: very low quality of evidence) and seroma rates (RR 0.71, 95% CI 0.37 to 1.35; two studies, 528 breasts: very low quality of evidence). None of the studies reported patient-related outcomes. ICGA protocols: eight studies used the SPY System and one study used the Photodynamic Eye imaging system (PDE) to assess MSFN. ICGA protocols in the included studies were not extensively described in most studies.

AUTHORS' CONCLUSIONS

Although mastectomy skin flap perfusion is performed more frequently using ICGA as a helpful tool, there is a lack of high-quality evidence in the context of randomised controlled trials. The quality of evidence in this review is very low, since only nonrandomised cohort studies have been included. With the results from this review, no conclusions can be drawn about what method of assessment is best to use during breast reconstructive surgery. High-quality randomised controlled studies that compare the use of ICGA to assess MSFN compared to clinical evaluation are needed.

Fasciocutaneous anterolateral thigh flaps for complex abdominal wall reconstruction after resection of enterocutaneous fistulas and the role of indocyanine green angiography: a pilot study

Purpose

No previous study reported the use of a fasciocutaneous anterolateral thigh (ALT) flap combined with a biological mesh for abdominal wall reconstruction (AWR) after enterocutaneous fistula (ECF) in a single-staged procedure and the use of Indocyanine Green Angiography (ICGA) intraoperatively. The purpose of this study was to determine the feasibility and safety of this procedure and to examine the added value of ICGA in minimizing postoperative complications.

Methods

A single-institution review of a prospectively maintained database was conducted at Maastricht University Medical Center. To evaluate the feasibility and safety of this procedure, early (≤ 30 days) and late (> 30 days) postoperative complications were assessed. ECF recurrence was considered the primary outcome. To examine the added value of ICGA, complications in the ICGA group and the non-ICGA group were compared descriptively.

Results

Ten consecutive patients, with a mean age of 66.7 years, underwent a single-staged AWR with fasciocutaneous ALT flaps. Mean follow-up was 17.4 months (4.3–28.2). Two early ECF recurrences were observed. Both restored without the need for reoperation. A lower rate of early complications was observed in the ICGA group compared to the non-ICGA group.

Conclusion

The combination of a biological mesh and fasciocutaneous ALT flap is feasible and safe in AWR after ECF repair in a single-staged approach, with an acceptable complication rate in a cohort of complex patients operated in a dedicated center. ECF closure was achieved in all patients. ICGA seems to be of great added value in minimizing postoperative complications during AWR.

Electronic supplementary material

The online version of this article (10.1007/s10029-020-02167-w) contains supplementary material, which is available to authorized users.

A novel study for fluorescence patterns of the parathyroid glands during surgery using a fluorescence spectroscopy system

PURPOSE

Recently it was reported that the parathyroid glands (PGs) emit autofluorescence when exposed to near infrared light, and a technique using fluorescence to detect the PGs intraoperatively was found to be useful. In some cases, however, it was difficult to detect the PGs. We sought to clarify the situation regarding such undetectable cases.

METHODS

The study comprised 45 patients (50 sides) who underwent thyroid or parathyroid surgery at Kushiro city general hospital between November 2018 and June 2019. We searched for the PGs intraoperatively using a fluorescence spectroscopy system. We statistically considered the factors related to the fluorescence patterns of background in cases in which two PGs could not be confirmed using Fisher's exact test. Factors included age, gender, body-mass index, laterality, disease state, renal function, and comorbidity.

RESULTS

In 41 sides (82%) fluorescence from at least one PG was determined. There was no significant difference in the detection rates among the other clinical factors. A "White out" pattern in which the background was too bright to detect PGs was observed in 11 sides (22%), and a "Black out" pattern in which the background and PGs were dark was observed in 18 sides (36%). Malignant disease was statistically associated with a "White out" pattern. No factors were found to be related to the "Black out" pattern.

CONCLUSION

In malignant disease, we should use this novel approach carefully.

First-in-human robotic supermicrosurgery using a dedicated microsurgical robot for treating breast cancer-related lymphedema: a randomized pilot trial

Advancements in reconstructive microsurgery have evolved into supermicrosurgery; connecting vessels with diameter between 0.3 and 0.8 mm for reconstruction of lymphatic flow and vascularized tissue transplantation. Supermicrosurgery is limited by the precision and dexterity of the surgeon’s hands. Robot assistance can help overcome these human limitations, thereby enabling a breakthrough in supermicrosurgery. We report the first-in-human study of robot-assisted supermicrosurgery using a dedicated microsurgical robotic platform. A prospective randomized pilot study is conducted comparing robot-assisted and manual supermicrosurgical lymphatico-venous anastomosis (LVA) in treating breast cancer-related lymphedema. We evaluate patient outcome at 1 and 3 months post surgery, duration of the surgery, and quality of the anastomosis. At 3 months, patient outcome improves. Furthermore, a steep decline in duration of time required to complete the anastomosis is observed in the robot-assisted group (33–16 min). Here, we report the feasibility of robot-assisted supermicrosurgical anastomosis in LVA, indicating promising results for the future of reconstructive supermicrosurgery.

Reconstructive microsurgery is limited by the precision that human hands can achieve. Here, the authors demonstrate in a randomized clinical pilot trial the feasibility of robot-assisted supermicrosurgery using a dedicated microsurgical robot for the completion of lymphatico-venous anastomosis in the treatment of breast cancer-related lymphedema

Mini-Platform for Off-On Near-Infrared Fluorescence Imaging Using Peptide-Targeting Ligands

Here, we propose a zwitterionic near-infrared (NIR) fluorophore-tryptophan (Trp) conjugate with a cleavable linker as a minimal-sized versatile platform (MP) for the preparation of peptide ligand-based off-on type molecular probes. The zwitterionic NIR fluorophore in MP undergoes fluorescence quenching via a photoinduced electron transfer mechanism when in close proximity to tryptophan, and nonspecific binding with serum proteins is minimized by the zwitterionicity of the fluorophore. The linker can be cleaved inside cancer cells in response to tumor-associated stimuli. As a proof-of-concept experiment, ATTO655 was covalently linked with Trp via a diarginine linker to form an MP. A cyclic peptide consisting of Arg-Gly-Asp-d-Phe-Lys (cRGD) was used as a cancer-targeting ligand and was conjugated to the MP to form cRGD-MP. The NIR fluorescence of cRGD-MP could be selectively turned on inside the target cancer cells, thereby enabling specific fluorescence imaging of integrin α_vβ₃-overexpressing cancer cells in vitro and in vivo.

Fluorescence imaging reversion using spatially variant deconvolution

Fluorescence imaging opens new possibilities for intraoperative guidance and early cancer detection, in particular when using agents that target specific disease features. Nevertheless, photon scattering in tissue degrades image quality and leads to ambiguity in fluorescence image interpretation and challenges clinical translation. We introduce the concept of capturing the spatially-dependent impulse response of an image and investigate Spatially Adaptive Impulse Response Correction (SAIRC), a method that is proposed for improving the accuracy and sensitivity achieved. Unlike classical methods that presume a homogeneous spatial distribution of optical properties in tissue, SAIRC explicitly measures the optical heterogeneity in tissues. This information allows, for the first time, the application of spatially-dependent deconvolution to correct the fluorescence images captured in relation to their modification by photon scatter. Using experimental measurements from phantoms and animals, we investigate the improvement in resolution and quantification over non-corrected images. We discuss how the proposed method is essential for maximizing the performance of fluorescence molecular imaging in the clinic.

Optimizing Indocyanine Green Fluorescence Angiography in Reconstructive Flap Surgery: A Systematic Review and Ex Vivo Experiments

Background. Indocyanine green angiography (ICGA) offers the potential to provide objective data for evaluating tissue perfusion of flaps and reduce the incidence of postoperative necrosis. Consensus on ICGA protocols and information on factors that have an influence on fluorescence intensity is lacking. The aim of this article is to provide a comprehensive insight of in vivo and ex vivo evaluation of factors influencing the fluorescence intensity when using ICGA during reconstructive flap surgery. Methods. A systematic literature search was conducted to provide a comprehensive overview of currently used ICGA protocols in reconstructive flap surgery. Additionally, ex vivo experiments were performed to further investigate the practical influence of potentially relevant factors. Results. Factors that are considered important in ICGA protocols, as well as factors that might influence fluorescence intensity are scarcely reported. The ex vivo experiments demonstrated that fluorescence intensity was significantly related to dose, working distance, angle, penetration depth, and ambient light. Conclusions. This study identified factors that significantly influence the fluorescence intensity of ICGA. Applying a weight-adjusted ICG dose seems preferable over a fixed dose, recommended working distances are advocated, and the imaging head during ICGA should be positioned in an angle of 60° to 90° without significantly influencing the fluorescence intensity. All of these factors should be considered and reported when using ICGA for tissue perfusion assessment during reconstructive flap surgery.

Fluorescent indocyanine green angiography: Preliminary results in microsurgery monitoring

INTRODUCTION

Pedicled flaps and free-tissue transfer flaps are used routinely to reconstruct hard and soft tissue defects in head and neck, limb, hand, thoracic and abdominopelvic reconstructive surgery. But failure remains a constant concern, particularly in free-tissue transfers. Usually failure is due to blood supply compromise. Indocyanine green (ICG), a fluorescent dye is a suitable tracer for vessel perfusion. The objective of this study is to evaluate the fluorescent indocyanine green angiography (FA ICG) in free flaps procedures.

MATERIEL AND METHODS

Patients who had microsurgical flap reconstruction were included during the study period in a single center. The FA ICG was used at specific times. Intra-veinous injections of 0.1mg/kg of INFRACYANINE^® (concentration 2.5mg/mL) were done intraoperatively. The Fluobeam^® device programmed on sensitivity and mapping to interpret the data, was used. These different injections allowed to checked skin paddle perforators vessels, osseous perforators vessels, arterial and venous patency after anastomosis and the cutaneous, muscular and osseous perfusion.

RESULTS

A total of 12 patients enrolled were 10 males and 1 female. Their mean age was 54.5 years (range 25-75 years). Of the 12 flaps, 8 were free flaps with 4 fibular flaps (3 for mandibular reconstruction and one for femur reconstruction); 2 radial forearm flaps for maxillary reconstruction; one latissimus free flap for tibia skin coverage and one retroauricular fasciocutaneous free flap for thumb skin coverage. We got to modify specific steps during surgery with 8 patients by using the FA ICG to anticipate potential complications: modifying the draw of the skin paddle, recut of this paddle, modifying the osteotomies, re-doing the anastomosis or modifying the position of the pivot point.

DISCUSSION

Evaluation of microvascular flap perfusion is still based on subjective clinical features. Clinical monitoring is observer-dependent and does not allow information sharing, test reproducibility, and consistent postoperative follow-up. The successful of salvage rate is linked to the delay between the onset of ischemia and its clinical assessment. FA ICG could be a reliable method for monitoring free-tissue transfers. This technique is objective, non invasive and facilitate a complex reconstructive procedure to augment is liability. This technique may be used such a pedagogical tool for young practitioners in their first microsurgery procedures.

Robotic (super) microsurgery: Feasibility of a new master-slave platform in an in vivo animal model and future directions

Advanced microsurgical procedures are currently limited by human precision and manual dexterity. The potential of robotics in microsurgery is highlighted, including a general overview of applications of robotic assistance in microsurgery and its introduction in different surgical specialties. A new robotic platform especially designed for (super) microsurgery is presented. Results of an in vivo animal study underline its feasibility and encourage further development toward clinical studies. Future directions of robotic microsurgery are proposed.

Potential of near-infrared fluorescence image-guided debridement in trauma surgery

This case report presents the use of near-infrared fluorescence (NIRF) imaging using indocyanine green (ICG) and its potential for the evaluation of soft tissue viability in a traumatic case. Standard implementation of this novel imaging modality might decrease the number of surgical debridement procedures in complex traumatic wounds.