Rutger M. Schols

Advanced intraoperative imaging methods for laparoscopic anatomy navigation: an overview

BackgroundSafety 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.MethodsA 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.ResultsVarious 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.ConclusionImplementation 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.

Near-Infrared Fluorescence Laparoscopy of the Cystic Duct and Artery in Pigs: Performance of a Preclinical Dye

BACKGROUND Near-infrared fluorescence laparoscopy after intravenous indocyanine green (ICG) administration has been proposed as a promising surgical imaging technique for real-time visualization of the extrahepatic bile ducts and arteries in clinical laparoscopic cholecystectomies. However, optimization of this new technique with respect to the imaging system combined with the fluorophore is desirable. The performance of a preclinical near-infrared dye, CW800-CA, was compared with that of ICG for near-infrared fluorescence laparoscopy of the cystic duct and artery in pigs. MATERIALS AND METHODS Laparoscopic cholecystectomy was performed in six pigs (average weight, 35 kg) using a commercially available laparoscopic fluorescence imaging system. The fluorophores CW800-CA and ICG (both 800 nm fluorescent dyes) were administered by intravenous injection in four and two pigs, respectively. CW800-CA was administered in three different doses (consecutively 0.25, 1, and 3 mg); ICG was intravenously injected (2.5 mg) for comparison. Intraoperative recognition of the biliary structures was recorded at set time points. The target-to-background ratio was determined to quantify the fluorescence signal of the designated tissues. RESULTS A clinically proven dose of 2.5 mg of ICG resulted in a successful fluorescence delineation of both the cystic duct and artery. In the CW800-CA-injected pigs a clear visualization of the cystic duct and artery was obtained after administration of 3 mg of CW800-CA. Time from injection until fluorescence identification of the cystic duct was reduced when CW800-CA was used compared with ICG (11.5 minutes versus 21.5 minutes, respectively). CW800-CA provided clearer illumination of the cystic artery, in terms of target-to-background ratio. CONCLUSIONS As well as ICG, CW800-CA can be applied for fluorescence identification of the cystic artery and duct using a commercially available laparoscopic fluorescence imaging system. Fluorescence cholangiography of the cystic duct can be obtained earlier after intravenous injection of CW800-CA, compared with ICG. These findings increase the possibilities of use and of optimization of this imaging technique.

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

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.

Near-infrared fluorescence cholangiography assisted laparoscopic cholecystectomy versus conventional laparoscopic cholecystectomy (FALCON trial): study protocol for a multicentre randomised controlled trial

Introduction Misidentification of the extrahepatic bile duct anatomy during laparoscopic cholecystectomy (LC) is the main cause of bile duct injury. Easier intraoperative recognition of the biliary anatomy may be accomplished by using near-infrared fluorescence (NIRF) imaging after an intravenous injection of indocyanine green (ICG). Promising results were reported for successful intraoperative identification of the extrahepatic bile ducts compared to conventional laparoscopic imaging. However, routine use of ICG fluorescence laparoscopy has not gained wide clinical acceptance yet due to a lack of high-quality clinical data. Therefore, this multicentre randomised clinical study was designed to assess the potential added value of the NIRF imaging technique during LC. Methods and analysis A multicentre, randomised controlled clinical trial will be carried out to assess the use of NIRF imaging in LC. In total, 308 patients scheduled for an elective LC will be included. These patients will be randomised into a NIRF imaging laparoscopic cholecystectomy (NIRF-LC) group and a conventional laparoscopic cholecystectomy (CLC) group. The primary end point is time to ‘critical view of safety’ (CVS). Secondary end points are ‘time to identification of the cystic duct (CD), of the common bile duct, the transition of CD in the gallbladder and the transition of the cystic artery in the gallbladder, these all during dissection of CVS’; ‘total surgical time’; ‘intraoperative bile leakage from the gallbladder or cystic duct’; ‘bile duct injury’; ‘postoperative length of stay’, ‘complications due to the injected ICG’; ‘conversion to open cholecystectomy’; ‘postoperative complications (until 90 days postoperatively)’ and ‘cost-minimisation’. Ethics and dissemination The protocol has been approved by the Medical Ethical Committee of Maastricht University Medical Center/Maastricht University; the trial has been registered at ClinicalTrials.gov. The findings of this study will be disseminated widely through peer-reviewed publications and conference presentations. Trial registration number NCT02558556.

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.

Near-Infrared Fluorescence Imaging for Real-Time Intraoperative Guidance in Anastomotic Colorectal Surgery: A Systematic Review of Literature

PURPOSE The aims of this review are to determine the feasibility of near-infrared fluorescence (NIRF) angiography in anastomotic colorectal surgery and to determine the effectiveness of the technique in improving imaging and quantification of vascularization, thereby aiding in decision making as to where to establish the anastomosis. METHODS A systematic literature search of PubMed and EMBASE was conducted. Searching through the reference lists of selected articles identified additional studies. All English language articles presenting original patient data regarding intraoperative NIRF angiography were included without restriction of type of study, except for case reports, technical notes, and video vignettes. The intervention consisted of intraoperative NIRF angiography during anastomotic colorectal surgery to assess perfusion of the colon, sigmoid, and/or rectum. Primary outcome parameters included ease of use, added surgical time, complications related to the technique, and costs. Other relevant outcomes were whether this technique changed intraoperative decision making, whether effort was taken by the authors to quantify the signal and the incidence of postoperative complications. RESULTS Ten studies were included. Eight of these studies make a statement about the ease of use. In none of the studies complications due to the use of the technique occurred. The technique changed the resection margin in 10.8% of all NIRF cases. The anastomotic leak rate was 3.5% in the NIRF group and 7.4% in the group with conventional imaging. Two of the included studies used an objective quantification of the fluorescence signal and perfusion, using ROIs (Hamamatsu Photonics) and IC-Calc® respectively. CONCLUSIONS Although the feasibility of the technique seems to be agreed on by all current research, large clinical trials are mandatory to further evaluate the added value of the technique.

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.

Lipofilling may induce nerve regeneration after previous traumatic injury: a clinical case with remarkable outcome

Despite the fast amount of techniques, which promote nerve regeneration, the outcomes of high ulnar nerve injuries are still poor. This case report illuminates the usability of lipofilling in peripheral nerve regeneration. In the case described, we encountered a successful regeneration with return of sensibility and motor function. We believe that the rationale for this technique is the presence of adipose-derived stem cells (ADSCs). We speculate that this improvement depends on tissue regeneration induced by these ADSCs.Level of Evidence: Level V, therapeutic study.

Merged Near-Infrared Fluorescence and White Light Imaging in Minimally Invasive Surgery

Dear Editor, We thank the author for his interest in and comment on our manuscript. As we stated in the discussion, merged white light (WL) and near-infrared fluorescence (NIRF) imaging is one of the points that need improvement in the current fluorescence imaging systems for minimally invasive surgery. We admit the omission of not having included the two papers by Sherwinter reporting on the Pinpoint system. Probably these studies, on transanal endoscopic imaging, were not detected by our search as we did not specifically search for endoscopic devices for transanal application. The third study, on robotic fluorescence imaging, mentions ‘‘merging’’ of NIRF imaging with the ‘‘black and white’’ image (i.e., not the WL image). By ‘‘merging’’ we specifically mean the composite of the NIRF image and the (high-definition) WL anatomical image, which is not widely available in the present commercial systems. Perhaps we should have better defined the term ‘‘merging’’ in our manuscript. We therefore thank the author for his comment and feel supported by Dr Sherwinter that merging of WL and NIRF images is important to improve the value of NIRF imaging in minimally invasive surgery.

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

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.