Robotic Microsurgery in Plastic and Reconstructive Surgery: A Literature Review.

BACKGROUND: Surgical robots have innovated the microsurgical field by providing advantages that improve surgical performance. These robots have been adopted by certain specialties more than others. This study discusses the potential advantages of robotics in plastic and reconstructive surgery. METHOD: This study is a literature review of articles investigating "robotic microsurgery in plastic and reconstructive surgery" using the PubMed database and the Cochrane Library. RESULT: A total of nineteen relevant articles were found and 5 articles performed a direct comparison between the robotic and manual approaches. Longer operating times were reported in the robotic groups featuring higher learning curves. Reported advantages to robotic use included higher accuracy, precision and flexibility, elimination of tremor and improvement of ergonomic factors. CONCLUSION: While the results provide an outlook into the outcome of robotic platforms in this field, current research is limited and further studies are required to provide a fundamental analysis.

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.

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.

Economic Analysis of Noninvasive Tissue Oximetry for Postoperative Monitoring of Deep Inferior Epigastric Perforator Flap Breast Reconstruction: A Review.

Background. Postoperative monitoring of deep inferior epigastric perforator (DIEP) flaps for breast reconstruction using noninvasive tissue oximetry enables timely recognition of vascular compromise. This may limit ischemic tissue damage, minimizing postoperative morbidity and healthcare costs. The aim of this review was to provide an economic analysis of tissue oximetry for postoperative monitoring of DIEP flap breast reconstruction. Methods. A systematic literature search was conducted utilizing PubMed and Embase. Articles reporting costs related to tissue oximetry following DIEP flap breast reconstruction, costs directly related to DIEP flap surgical procedure, and costs associated with postoperative complications were included. Risk of bias was assessed using different tools depending on study type. Results. Six articles were included. Four studies provided an overview of total costs associated with DIEP flap breast reconstruction; two studies focused on whether tissue oximetry could facilitate a decrease in hospital costs. Average overall costs for DIEP flap procedure were estimated at $28 000, with additional costs up to $37 530 in case of total flap failure. Tissue oximetry to monitor DIEP flaps could potentially save up to $1667 per procedure. Moreover, it might eliminate the need for specialized postoperative care. Conclusion. Tissue oximetry following DIEP flap breast reconstruction can potentially facilitate a decrease in hospital costs since its readings enable physicians to intervene in an early stage of tissue malperfusion, contributing to minimizing complications. Tissue oximetry may eliminate the need for specialized postoperative care. However, based on the current literature, no firm conclusions can yet be drawn regarding cost-effectiveness of standard implementation.

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.

Near-infrared fluorescence image-guidance in anastomotic colorectal cancer surgery and its relation to serum markers of anastomotic leakage: a clinical pilot study.

OBJECTIVE: Near-infrared fluorescence (NIRF) imaging using indocyanine green (ICG) might help reduce anastomotic leakage (AL) after colorectal surgery. This pilot study aims to analyze whether a relation exists between measured fluorescence intensity (FI) and postoperative inflammatory markers of AL, C-reactive protein (CRP), Intestinal fatty-acid binding protein (I-FABP), and calprotectin, to AL, in order to evaluate the potential of FI to objectively predict AL. METHODS: Patients scheduled for anastomotic colorectal cancer surgery were eligible for inclusion in this prospective pilot study. During surgery, at three time points (after bowel devascularization; before actual transection; after completion of anastomosis) a bolus of 0.2 mg/kg ICG was administered intravenously for assessment of bowel perfusion. FI was scored in scale from 1 to 5 based on the operating surgeon's judgment (1 = no fluorescence visible, 5 = maximum fluorescent signal). The complete surgical procedure was digitally recorded. These recordings were used to measure FI postoperatively using OsiriX imaging software. Serum CRP, I-FABP, and calprotectin values were determined before surgery and on day 1, 3, and 5 postoperative; furthermore, the occurrence of AL was recorded. RESULTS: Thirty patients (n = 19 males; mean age 67 years; mean BMI 27.2) undergoing either laparoscopic or robotic anastomotic colorectal surgery were included. Indication for surgery was rectal-(n = 10), rectosigmoid-(n = 2), sigmoid-(n = 10), or more proximal colon carcinomas (n = 8). Five patients (16.7%) developed AL (n = 2 (6.6%) grade C according to the definition of the International Study group of Rectal Cancer). In patients with AL, the maximum fluorescence score was given less often (P = 0.02) and a lower FI compared to background FI was measured at 1st assessment (P = 0.039). However, no relation between FI and postoperative inflammatory parameters could be found. CONCLUSION: Both subjective and measured FI seem to be related to AL. In this study, no relation between FI and inflammatory serum markers could yet be found.

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.

Near-infrared fluorescence imaging for real-time intraoperative anatomical guidance in minimally invasive surgery: a systematic review of the literature.

INTRODUCTION: Near-infrared fluorescence (NIRF) imaging, using contrast agents with fluorescent characteristics in the near-infrared (NIR: 700-900 nm) window, is considered to possess great potential for clinical practice in the future of minimally invasive surgery (MIS), given its capacity for intraoperative, real-time anatomical navigation, and identification. The aim of this review is to provide an overview of the literature concerning the current and potential future applications of fluorescence imaging in supporting anatomical guidance during MIS, and thereby guiding future research. METHODS: A systematic literature search was performed in the PubMed and Embase databases. All identified articles were screened and checked for eligibility by two authors. In addition, literature was sought by screening references of eligible articles. RESULTS: After administration of a fluorescent dye (e.g., indocyanine green), NIRF imaging can be helpful to improve the visualization of vital anatomical structures during MIS. Extra-hepatic bile ducts, arteries, ureters, sentinel lymph nodes, and lymph vessels have successfully been identified using NIRF imaging. A uniform approach regarding timing and route of dye administration has not yet been established. Optimization of both imaging systems and fluorescent dyes is needed to improve current shortcomings. New preclinical dyes are considered for optimization of NIRF imaging. CONCLUSION: Future implementation of new intraoperative optical methods, such as NIRF, could significantly contribute to intraoperative anatomy navigation and facilitate critical decision-making in MIS. Further research (i.e., large multi-center randomized controlled trials) is needed to establish the true value of this innovative optical imaging technique in standard clinical practice.

Automated Spectroscopic Tissue Classification in Colorectal Surgery.

BACKGROUND: In colorectal surgery, detecting ureters and mesenteric arteries is of utmost importance to prevent iatrogenic injury and to facilitate intraoperative decision making. A tool enabling ureter- and artery-specific image enhancement within (and possibly through) surrounding adipose tissue would facilitate this need, especially during laparoscopy. To evaluate the potential of hyperspectral imaging in colorectal surgery, we explored spectral tissue signatures using single-spot diffuse reflectance spectroscopy (DRS). As hyperspectral cameras with silicon (Si) and indium gallium arsenide (InGaAs) sensor chips are becoming available, we investigated spectral distinctive features for both sensor ranges. METHODS: In vivo wide-band (wavelength range 350-1830 nm) DRS was performed during open colorectal surgery. From the recorded spectra, 36 features were extracted at predefined wavelengths: 18 gradients and 18 amplitude differences. For classification of respectively ureter and artery in relation to surrounding adipose tissue, the best distinctive feature was selected using binary logistic regression for Si- and InGaAs-sensor spectral ranges separately. Classification performance was evaluated by leave-one-out cross-validation. RESULTS: In 10 consecutive patients, 253 spectra were recorded on 53 tissue sites (including colon, adipose tissue, muscle, artery, vein, ureter). Classification of ureter versus adipose tissue revealed accuracy of 100% for both Si range and InGaAs range. Classification of artery versus surrounding adipose tissue revealed accuracies of 95% (Si) and 89% (InGaAs). CONCLUSIONS: Intraoperative DRS showed that Si and InGaAs sensors are equally suited for automated classification of ureter versus surrounding adipose tissue. Si sensors seem better suited for classifying artery versus mesenteric adipose tissue. Progress toward hyperspectral imaging within this field is promising.

Application of a new dye for near-infrared fluorescence laparoscopy of the ureters: demonstration in a pig model.

BACKGROUND: Ureteral injury during laparoscopic colorectal surgery is a rare but serious complication with a reported incidence rate of 0.66%. The early detection and prevention of ureteral injury is clinically relevant and important. The successful use of preclinical near-infrared fluorophore CW800-CA for real-time intraoperative identification of the anatomical course of the ureters with the use of a laparoscopic fluorescence imaging system is reported. METHODS: The usefulness of this new imaging technique was explored in two 35-kg pigs. Intravenous CW800-CA was administered 10 minutes before fluorescence imaging was conducted with the use of a commercially available laparoscopic fluorescence imaging system. RESULTS: A dose of 1 mg/mL CW800-CA (bolus injection of 3 mL) provided clear delineation of the course of both ureters by using the fluorescence mode of the laparoscope. There were no adverse reactions to the injected dye. CONCLUSION: Near-infrared fluorescence laparoscopy of the ureters, following intravenous CW800-CA administration, is easily applicable and provides real-time identification of the course of the ureters.

Differentiation between nerve and adipose tissue using wide-band (350-1,830 nm) in vivo diffuse reflectance spectroscopy.

BACKGROUND: Intraoperative nerve localization is of great importance in surgery. In certain procedures, where nerves show visual resemblance to surrounding adipose tissue, this can be particularly challenging for the human eye. An example of such a delicate procedure is thyroid and parathyroid surgery, where iatrogenic injury of the recurrent laryngeal nerve can result in transient or permanent vocal problems (0.5-2.0% reported incidence). A camera system, enabling nerve-specific image enhancement, would be useful in preventing such complications. This might be realized with hyperspectral camera technology using silicon (Si) or indium gallium arsenide (InGaAs) sensor chips. METHODS: As a first step towards such a camera, we evaluated the performance of diffuse reflectance spectroscopy by analysing spectra collected during 18 thyroid and parathyroid resections. We assessed the contrast information present in two different spectral ranges, for respectively Si and InGaAs sensors. Two hundred fifty three in vivo, wide-band diffuse reflectance spectra (350-1,830 nm range, 1 nm resolution) were acquired on 52 tissue spots, including nerve (n = 22), muscle (n = 12), and adipose tissue (n = 18). We extracted 36 features from these spectroscopic data: 18 gradients and 18 amplitude differences at predefined points in the tissue spectra. Best distinctive feature combinations were established using binary logistic regression. Classification performance was evaluated in a cross-validation (CV) approach by leave-one-out (LOO). To generalize nerve recognition applicability, we performed a train-test (TT) validation using the thyroid and parathyroid surgery data for training purposes and carpal tunnel release surgery data (10 nerve spots and 5 adipose spots) for classification purposes. RESULTS: For combinations of two distinctive spectral features, LOO revealed an accuracy of respectively 78% for Si-sensors and 95% for InGaAs-sensors. TT revealed accuracies of respectively 67% and 100%. CONCLUSIONS: Using diffuse reflectance spectroscopy we have identified that InGaAs sensors are better suited for automated discrimination between nerves and surrounding adipose tissue than Si sensors.

Advanced intraoperative imaging methods for laparoscopic anatomy navigation: an overview.

BACKGROUND: Safety and efficiency are important topics in minimally invasive surgery. Apart from its advantages, laparoscopic surgery has the following drawbacks: two-dimensional imaging, challenging eye-hand coordination, and absence of tactile feedback. Enhanced imaging with earlier and clearer identification of essential tissue types can partly overcome these disadvantages. Research groups worldwide are investigating new technologies for image-guided surgery purposes. This review article gives an overview of current developments in surgical optical imaging for improved anatomic identification and physiologic tissue characterization during laparoscopic gastrointestinal surgery. METHODS: A systematic literature search in the PubMed database was conducted. Eligible studies reported on any kind of novel optical imaging technique applied for anatomic identification or physiologic tissue characterization in laparoscopic gastrointestinal surgery. Gynecologic and urologic procedures also were included whenever vascular, nerve, ureter, or lymph node imaging was concerned. RESULTS: Various surgical imaging techniques for enhanced intraoperative visualization of essential tissue types (i.e., blood vessel, bile duct, ureter, nerve, lymph node) and for tissue characterization purposes such as assessment of blood perfusion were identified. An overview of preclinical and clinical experiences is given as well as the potential added value for intraoperative anatomic localization and characterization during laparoscopy. CONCLUSION: Implementation of new optical imaging methods during laparoscopic gastrointestinal surgery can improve intraoperative anatomy navigation. This may lead to increased patient safety (preventing iatrogenic functional tissue injury) and procedural efficiency (shorter operating time). Near-infrared fluorescence imaging seems to possess the greatest potential for implementation in clinical practice in the near future.

Fluorescence cholangiography during laparoscopic cholecystectomy: a feasibility study on early biliary tract delineation.

BACKGROUND: Laparoscopic cholecystectomy (LC) is one of the most commonly performed laparoscopic procedures. Bile duct injury is a rare but serious complication during this procedure, mostly caused by misidentification of the extrahepatic bile duct anatomy. Intraoperative cholangiography may be helpful to reduce the risk of bile duct injury; however, this is not a common procedure worldwide. Near-infrared fluorescence cholangiography (NIRFC) using indocyanine green (ICG) is a promising alternative for the identification of the biliary tree. This prospective observational study was designed to assess the feasibility and image quality of intermittent NIRFC during LC, using a newly developed laparoscopic fluorescence system. METHODS: Consecutive patients undergoing elective LC were included and received a single intravenous injection of ICG directly after induction of anesthesia. During dissection of the base of the gallbladder and the cystic duct, the extrahepatic bile ducts were visualized by using a dedicated laparoscope, which offers both conventional state-of-the-art imaging and fluorescence imaging. Intraoperative recognition of the biliary structures was registered at set time points, as well as the establishment of the critical view of safety. RESULTS: Fifteen patients were included between December 2011 and May 2012. ICG was visible in the liver and bile ducts within 20 min after intravenous administration and remained for approximately 2 h, using the fluorescence mode of the laparoscope. The common bile duct and cystic duct could be clearly identified at an early stage of the operation and, more important, significantly earlier than with the conventional camera mode. No per- or postoperative complications occurred as a consequence of ICG use. CONCLUSIONS: Intermittent fluorescence imaging using a newly developed laparoscope and preoperative administration of ICG seems a useful aid in accelerating visualization of the extrahepatic bile ducts during laparoscopic cholecystectomy.

Combined vascular and biliary fluorescence imaging in laparoscopic cholecystectomy.

BACKGROUND: Bile duct injury in patients undergoing laparoscopic cholecystectomy is a rare but serious complication. Concomitant vascular injury worsens the outcome of bile duct injury repair. Near-infrared fluorescence imaging using indocyanine green (ICG) is a promising, innovative, and noninvasive method for the intraoperative identification of biliary and vascular anatomy during cholecystectomy. This study assessed the practical application of combined vascular and biliary fluorescence imaging in laparoscopic gallbladder surgery for early biliary tract delineation and arterial anatomy confirmation. METHODS: Patients undergoing elective laparoscopic cholecystectomy were enrolled in this prospective, single-institutional study. To delineate the major bile ducts and arteries, a dedicated laparoscope, offering both conventional and fluorescence imaging, was used. ICG (2.5 mg) was administered intravenously immediately after induction of anesthesia and in half of the patients repeated at establishment of critical view of safety for concomitant arterial imaging. During dissection of the base of the gallbladder and the cystic duct, the extrahepatic bile ducts were visualized. Intraoperative recognition of the biliary structures was registered at set time points, as well as visualization of the cystic artery after repeat ICG administration. RESULTS: Thirty patients were included. ICG was visible in the liver and bile ducts within 20 minutes after injection and remained up to approximately 2 h, using the ICG-filter of the laparoscope. In most cases, the common bile duct (83%) and cystic duct (97%) could be identified significantly earlier than with conventional camera mode. In 13 of 15 patients (87%), confirmation of the cystic artery was obtained successfully after repeat ICG injection. No per- or postoperative complications occurred as a consequence of ICG use. CONCLUSION: Biliary and vascular fluorescence imaging in laparoscopic cholecystectomy is easily applicable in clinical practice, can be helpful for earlier visualization of the biliary tree, and is useful for the confirmation of the arterial anatomy.

Near-Infrared Spectral Similarity between Ex Vivo Porcine and In Vivo Human Tissue.

BACKGROUND: In vivo diffuse reflectance spectroscopy provides additional contrast in discriminating nerves embedded in adipose tissue during surgery. However, large datasets are required to achieve clinically acceptable classification levels. This study assesses the spectral similarity between ex vivo porcine and in vivo human spectral data of nerve and adipose tissue, as porcine tissue could contribute to generate large datasets. METHODS: Porcine diffuse reflectance spectra were measured at 124 nerve and 151 adipose locations. A previously recorded dataset of 32 in vivo human nerve and 23 adipose tissue locations was used for comparison. In total, 36 features were extracted from the raw porcine to generate binary logistic regression models for all combinations of two, three, four and five features. Feature selection was performed by assessing similar means between normalized features of nerve and of adipose tissue (Kruskal-Wallis test, p < 0.05) and for models performing best on the porcine cross validation set. The human test set was used to assess classification performance. RESULTS: The binary logistic regression models with selected features showed an accuracy of 60% on the test set. CONCLUSIONS: Spectral similarity between ex vivo porcine and in vivo human adipose and nerve tissue was present, but further research is required.

Tissue Oximetry Changes during Postoperative Dangling in Lower Extremity Free Flap Reconstruction: A Pilot Study.

Background: Lower extremity free flap dangling protocols are still widely practiced, despite a paucity of evidence for their use. This pilot study investigates the use of tissue oximetry to provide further insight into the physiological effect of postoperative dangling in lower limb free flap transfer. Methods: Ten patients undergoing lower extremity free flap reconstruction were included in this study. Free flap tissue oxygen saturation (StO2) was continuously measured using non-invasive near-infrared spectroscopy. Measurements were performed on the free flap and contralateral limb during dangling from postoperative day (POD) 7 until 11, according to the local dangling protocol. Results: StO2 values measured in the free flap diminished to 70 ± 13.7% during dangling. This minimum StO2 was reached significantly later, and correspondingly the area under the curve (AUC) was significantly larger on POD 11 compared to the start of the dangling protocol on POD 7, reflecting an improving free flap microvascular reactivity. The dangling slope was equal between the free flap and contralateral leg. The reperfusion slope was significantly flatter on POD 7 compared to the other PODs (p < 0.001). Thereafter, no significant differences between PODs were observed. Patients with a history of smoking had significantly lower tissue oximetry values compared to non-smokers. Conclusions: The application of tissue oximetry during dangling provides further insight into the physiological effect (i.e., changes in microcirculatory function) of the free flap of the reconstructed lower extremity. This information could potentially be useful to either revise or disrupt the use of such dangling protocols.

First-in-Human Integrated Use of a Dedicated Microsurgical Robot with a 4K 3D Exoscope: The Future of Microsurgery.

Innovative techniques can help overcome the limitations of the human body. Operating on very small structures requires adequate vision of the surgical field and precise movements of sophisticated instruments. Both the human eye and hand are limited when performing microsurgery. Conventional microsurgery uses operation microscopes to enhance the visualization of very small structures. Evolving technology of high-definition 3D cameras provides the opportunity to replace conventional operation microscopes, thereby improving ergonomics for surgeons. This leaves the human hand as a limiting factor in microsurgery. A dedicated robot for microsurgery has been developed to overcome this limitation and enhance the precision and stability of the surgeons' hands. We present the first-in-human case in reconstructive microsurgery where both technologies are integrated using a dedicated microsurgical robot in combination with a 4K 3D exoscope.

Near-Infrared Spectroscopy (NIRS) versus Hyperspectral Imaging (HSI) to Detect Flap Failure in Reconstructive Surgery: A Systematic Review.

Rapid identification of possible vascular compromise in free flap reconstruction to minimize time to reoperation improves achieving free flap salvage. Subjective clinical assessment, often complemented with handheld Doppler, is the golden standard for flap monitoring; but this lacks consistency and may be variable. Non-invasive optical methods such as near-infrared spectroscopy (NIRS) and hyperspectral imaging (HSI) could facilitate objective flap monitoring. A systematic review was conducted to compare NIRS with HSI in detecting vascular compromise in reconstructive flap surgery as compared to standard monitoring. A literature search was performed using PubMed and Embase scientific database in August 2021. Studies were selected by two independent reviewers. Sixteen NIRS and five HSI studies were included. In total, 3662 flap procedures were carried out in 1970 patients using NIRS. Simultaneously; 90 flaps were performed in 90 patients using HSI. HSI and NIRS flap survival were 92.5% (95% CI: 83.3-96.8) and 99.2% (95% CI: 97.8-99.7). Statistically significant differences were observed in flap survival (p = 0.02); flaps returned to OR (p = 0.04); salvage rate (p < 0.01) and partial flap loss rate (p < 0.01). However, no statistically significant difference was observed concerning flaps with vascular crisis (p = 0.39). NIRS and HSI have proven to be reliable; accurate and user-friendly monitoring methods. However, based on the currently available literature, no firm conclusions can be drawn concerning non-invasive monitoring technique superiority.

Intraoperative fluorescence imaging in different surgical fields: Consensus among 140 intercontinental experts.

BACKGROUND: Despite exponentially growing evidence supporting the use of intraoperative fluorescence imaging + indocyanine green dye, considerable variability exists in how and when it is used, and no published consensus guidelines exist. We have conducted Delphi surveys of international experts in the use of intraoperative fluorescence imaging covering 6 distinct surgical scenarios: laparoscopic cholecystectomy; colorectal, lymphedema, gastric cancer, and plastic surgery; and thyroid and parathyroid resections. Although each survey asked experts to vote on field-specific consensus statements, they also had 29 shared statements to permit some analysis spanning the 6 specialties. This article summarizes these results. METHODS: Data on the 29 shared statements from 6 two-round Delphi consensus surveys were compiled to identify areas of overall consensus and compare the different specialties. As with the individual surveys, consensus was defined as ≥70% intervoter agreement. RESULTS: Among 140 participating experts, overall consensus was achieved on 16 statements, including strong agreement that using indocyanine green is extremely safe, that it can be used even when informed written consent cannot be provided, that it significantly enhances anatomical visualization and impacts how procedures are performed, and that it significantly reduces overall procedural risk. However, indocyanine green dosing and timing are procedure-specific, with considerable variability persisting for some applications, and the overall consensus is that further research is necessary to optimize this facet of intraoperative fluorescence imaging. CONCLUSION: Fluorescence imaging is gaining traction across multiple surgical specialties as an invaluable intraoperative tool. Its use in clinical practice and research seems destined to increase.