Development of a novel marking system for laparoscopic gastrectomy using endoclips with radio frequency identification tags: feasibility study in a canine model

Use of a radiofrequency identification system for precise sublobar resection of small lung cancers

BACKGROUND

The incidence of sublobar resection is increasing because of the rise in the detection of small lung cancers. However, local recurrence needs to be addressed, and several methods are needed for the resection with secure margins of non-visible and non-palpable tumors.

METHODS

We retrospectively reviewed the use of a radiofrequency identification (RFID) system in sublobar resection of adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) at our institute.

RESULTS

From June 2020 to June 2022, 39 patients underwent sublobar resection for AIS or MIA. The median age was 69 years (interquartile range, 64-76). Among the 39 patients, 24 were diagnosed with AIS and 15 with MIA. Segmentectomy, subsegmentectomy, and wedge resection were performed in nine, six, and 24 patients, respectively. The median size of the target tumor was 9.0 mm (8.1-12.9) and the median distance between the tag and the tumor was 2.9 mm (0-7.5). The median pathological surgical margin was 15.0 mm (10-17.5). Complete resection of all lesions was performed with a secure surgical margin. The median follow-up duration was 6 months, during which no local recurrence was detected in any of the patients.

CONCLUSIONS

The RFID marking system accurately informed the surgeons of the tumor location and helped them to perform precise sublobar resection.

Localization and Laparoscopic Excision of Gastric Heterotopic Pancreas in a Child by Endoscopic SPOT® Tattooing

Heterotopic pancreas (HP) is defined as pancreatic tissue lacking vascular or anatomic connection with the normal pancreas. Surgical resection is often indicated for symptomatic gastric HP. However, intraoperative identification of gastric HP is often difficult during laparoscopic surgery. Herein, we describe a patient with gastric HP, which was marked with SPOT^® dye (GI Supply, Camp Hill, PA, USA). The dye was seen clearly laparoscopically facilitating total excision of the lesion. The final pathology report confirmed the presence of heterotopic pancreatic tissue including pancreatic acini, small pancreatic ducts tissue with islets of Langerhans in the deep gastric submucosal area. There were no postoperative complications, and the patient was symptom-free. To the best of our knowledge, this was the first case report in the literature in which endoscopic tattooing of gastric HP before laparoscopic resection was performed. This method of localization was simple and reliable in children.

A Metal Detector for Clip Location Tracking of Stomach and Colon Cancer during Laparoscopic Surgery

In laparoscopic surgery for colorectal and gastric cancer, it is difficult to locate the tumor in the cavity for excision. Tumors in the colon or stomach are blocked by mucous membranes; thus, the view from the cavity is obscured. Therefore, to determine the location of the tumor, a marker can be installed around the tumor and the location of the tumor can be found using a sensor. Until now, most of the clip-detectors that have been developed can detect the location of tumors for either colorectal or gastric cancer. The research on the development of a detector that can detect the location of tumors for both colorectal and gastric cancer, is insufficient. Most detectors for tumor location determination are devised using a magnet by connecting a wire to a clip. In this method, the position of the magnet moves along the length of the wire. Therefore, it is difficult for the detector to detect the exact location of the tumor. Based on this method, this study designs a clip maker to determine the location of a tumor and a detector that can detect the clip. The clip and the sensing element are directly connected. The clip is developed using ferrite and coil to generate a magnetic field induced by an eddy current in the metal (clip), and the detector is designed using the Colpitts oscillator to induce a magnetic field. After installing the prepared clip at the tumor location, the detector is used to detect the clip, and accordingly, the location of the tumor can be identified using the detector. To test the performance of the clip and detector, we conducted animal experiments. In the course of the animal experiment, four clips were installed in the colon and stomach, and we succeeded in detecting all the clips. Because the clip-detector is used to locate the tumor during laparoscopic surgery, an endoscope must be used. Therefore, it is predicted that the demand for laparoscopic surgery and endoscopic medical industry will increase because of the clip-detector.

Clip-Detector Using a Neodymium Magnet to Locate Malignant Tumors during Laparoscopic Surgery

During laparoscopic surgery for colorectal or gastric cancers, locating the tumor for excision is difficult owing to it being obscured by mucous membranes. Therefore, a clip can be installed around the tumor, which can be located using a sensor. Most of the clip-detectors developed thus far can only detect tumors in either the colon or stomach and require a wire to connect the clip and detector. This study designs a clip and detector that can locate a tumor in the stomach and colon. The clip contains a neodymium magnet that generates a magnetic field, and the detector includes a Colpitts oscillator that allows magnetic coupling of the clip and detector. After installing the prepared clip at the tumor location, the detector is used to locate the clip. To test the clip and detector, we conducted animal experiments, during which four clips were installed in the colon and stomach of a mini pig. We succeeded in locating the clips within 2.17 and 3.14 s in the stomach and colon, respectively, which were shorter than the detection times reported in previous studies. The demand for laparoscopic surgery and endoscopes is predicted to increase owing to this method.

Simple and Reliable Method for Gastric Subepithelial Tumor Localization Using Endoscopic Tattooing before Totally Laparoscopic Resection

Background: Totally laparoscopic surgery for early gastric cancer and subepithelial tumors has been popularized worldwide, yet localization of early or small-sized tumors is a persistent challenge due to difficulty being identified with the lack of manual tactile sensation. Thus, accurate localization with tattooing before the surgery would help improve efficiency during surgery. There are multiple methods to localize tumors before laparoscopy, each with varying advantages and disadvantages. The use of endoscopic tattooing with dye has been carried out for several decades due to its safety, lower cost, and convenience. However, there is a lack of studies on endoscopic tattooing before totally laparoscopic resection. Aims: To evaluate the effect of endoscopic tattooing with dye for gastric subepithelial tumors localization before laparoscopic resection and to evaluate the tattooing effect on different locations of tumors in stomach. Method: We retrospectively collected data of patients with gastric subepithelial tumors who underwent endoscopic tattooing before totally laparoscopic resection from 2017 to 2020 in a university affiliated medical center. All patients were analyzed for preoperative characteristics and then categorized into two groups based on tumor locations concerning the difficulty of laparoscopic surgery. The independent t test and Chi-square test were performed to compare perioperative outcome and complications between these two groups. Result: A total of 19 patients were included retrospectively at our center. The individuals were 5 male and 14 female patients with a mean age of 58.2 years old. Most patients had no symptoms, and the tumors were found incidentally in 12 patients (63%). All tumors were identified clearly during laparoscopic resection. The mean tumor size was 2.3 cm. The surgeries took an average of 111 min and a mean of 7 mL blood loss was found. All tumors had negative resection margins with no recurrence during follow-up. Gastrointestinal stromal tumor was the major pathologic diagnosis, found in 12 patients (63%), followed by the leiomyoma in 5 patients (26%). Only three patients had mild adverse effects after surgery and the symptoms were self-limited. Our analysis found no significant difference in preoperative patient characteristics and perioperative outcomes between patients with differing tumor locations. Conclusion: This study is the first and largest report on endoscopic tattooing with dye before laparoscopic resection of gastric subepithelial tumor resection. Our results emphasize that endoscopic tattooing with dye is a safe and reliable method for localizing subepithelial tumors in the stomach prior to totally laparoscopic resection, with no correlation to where the tumor is located.

Technical Advances in Segmentectomy for Lung Cancer: A Minimally Invasive Strategy for Deep, Small, and Impalpable Tumors

With the increased detection of early-stage lung cancer and the technical advancement of minimally invasive surgery (MIS) in the field of thoracic surgery, lung segmentectomy using MIS, including video- and robot-assisted thoracic surgery, has been widely adopted. However, lung segmentectomy can be technically challenging for thoracic surgeons due to (1) complex segmental and subsegmental anatomy with frequent anomalies, and (2) difficulty in localizing deep, small, and impalpable tumors, leading to difficulty in obtaining adequate margins. In this review, we summarize the published evidence and discuss key issues related to MIS segmentectomy, focusing on preoperative planning/simulation and intraoperative tumor localization. We also demonstrate two of our techniques: (1) three-dimensional computed tomography (3DCT)-based resection planning using a novel 3DCT processing software, and (2) tumor localization using a novel radiofrequency identification technology.

Innovative marking method using novel endoscopic clip equipped with fluorescent resin to locate gastric cancer

An asymptomatic 76-year-old man presented to our department for the treatment of gastric cancer. Esophagogastroduodenoscopy revealed a superficial elevated lesion with an irregular central depression in the lower third of the stomach; this was confirmed to be adenocarcinoma by biopsy, while abdominal contrast-enhanced CT revealed no abnormal lesions. Based on the patient's clinical diagnosis of early gastric cancer, we planned laparoscopic gastrectomy with preoperative placement of four endoscopic marking clips equipped with indocyanine green-conjugated resin to determine the resection margin. During surgery, a dedicated laparoscopic system was used to detect indocyanine green fluorescence emitted by the clips and determine their precise position. The clips helped to identify an accurate resection line for the stomach, enabling accurate laparoscopic distal gastrectomy with regional lymphadenectomy. We successfully demonstrated the usefulness of clips with fluorescent resin for detecting gastric cancer in patients. We report the first case using the clips to accurately locate a site of interest.

Intraoperative Tumor Localization of Early Gastric Cancers

Recently, endoscopic screening systems have enabled the diagnosis of gastric cancer in the early stages. Early gastric cancer (EGC) is typically characterized by a shallow invasion depth and small size, which can hinder localization of EGC tumors during laparoscopic surgery. Here, we review nine recently reported tumor localization methods for the laparoscopic resection of EGCs. Preoperative dye or blood tattooing has the disadvantage of spreading. Preoperative 3-dimensional computed tomography reconstruction is not performed in real time during laparoscopic gastrectomy. Thus, they are considered to have a low accuracy. Intraoperative portable abdominal radiography and intraoperative laparoscopic ultrasonography methods can provide real-time feedback, but these methods require expertise, and it can be difficult to define the clips in some gastric regions. Despite a few limitations, intraoperative gastrofibroscopy provides real-time feedback with high accuracy. The detection system using an endoscopic magnetic marking clip, fluorescent clip, and radio-frequency identification detection system clip is considered highly accurate and provides real-time feedback; we expect a commercial version of this setup to be available in the near future. However, there is not yet an easy method for accurate real-time detection. We hope that improved devices will soon be developed and used in clinical settings.

Endoscopic Preoperative Tattooing and Marking in the Gastrointestinal Tract: A Systematic Review of Alternative Methods

Background: An accurate and reliable localization of endoluminal gastrointestinal (GI) lesions is crucial, particularly during minimally invasive surgery. As an extreme consequence, a misdetected GI lesion can lead to the resection of the wrong segment, especially in colorectal surgery. A preoperative endoscopic marking is recommended in case of GI lesions, which are expected to be difficult to detect from the serosal side. In clinical practice, three preoperative endoscopic marking methods are currently used: India ink, SPOT™, and endoclips with intraoperative fluoroscopy. All of them have substantial limitations. This has encouraged research on alternative solutions. Methods: In the current systematic review, animal and clinical studies about alternative preoperative endoscopic marking methods of GI lesions were analyzed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Results: Thirty studies were found using PubMed/MEDLINE, EMBASE/Ovid, and the Cochrane Library for the qualitative analysis. Conclusion: Although several smart solutions have been proposed and tested successfully, all of them seem to have a substantial drawback related either to scarce stability on the marking site or potential spreading on the bowel wall or diffusion into the surgical planes.

An advanced RFID-based system to localize gastric and colon cancers during laparoscopic surgery

BACKGROUND

We aimed to improve the tumor localization system using radiofrequency identification (RFID) technology used during laparoscopic surgery for gastric and colorectal cancer. To this end, we developed a detection algorithm and designed improvement for the RFID clip.

METHODS

To evaluate the proposed system, a swine-based animal study was conducted, followed by experiments on porcine stomachs and colons using the EASIE-R simulator. The success rates of endoscopic clipping, detection time, and detection accuracy, which is the distance between the detection point and RFID tag, were measured.

RESULTS

Results of the in vivo swine animal study showed success in all three clippings and detections of the RFID clips. Results of the 60 RFID endoclip attempts using the EASIE-R simulator showed a total clipping success rate of 85.0% (n = 51/60; stomach, 83.3%, n = 25/30; colon, 86.7%, n = 26/30). The median detection times were 29.2 s for the stomach and 25.5 s for the colon. The median detection accuracy was 4.0 mm for the stomach and 4.5 mm for the colon.

CONCLUSIONS

We confirmed that the proposed RFID-based system showed improvements over the system of a previous study. This RFID-based system is effective at localizing gastric and colorectal tumors.

New inductive proximity sensor platform for precise localization of small colorectal tumors

Location of small gastric or colorectal tumors during a laparoscopic procedure is often imprecise and can be misleading. There is a real need for a compatible and straightforward tool that can be used intraoperatively to help the surgeon in this regard. We emphasize in the present work on the fabrication of a new and innovative inductive proximity switch architecture, fully compatible with laparoscopic surgery and with direct application in precise localisation of bowel tumors. An electromagnetic detection probe optimized for laparoscopic surgery and preconditioned for sterilisation was designed and constructed. Various metallic markers designed to be attached to the gastrointestinal mucosa were used for detection by the probe, from standard endoscopic and laparoscopic haemostatic clips to other custom made tags. Experiments were performed in dry and wet-lab experimental laboratory environment using ex-vivo segments of calf's small bowel and colonic surgical specimens from human patients. The dry-lab detection range varied considerably depending on the metallic component of the tags, from 0.5 mm for the endoscopic hemostatic clip to 3.5 mm for the 0.9 mm thickness stainless-steel custom tags. The latter was actually detectable from the serosal side of the fresh colonic surgical specimens in 85% of the attempts if the scanned area was less than 150 cm² and less than 2 mm of fat was interposed between the probe and the bowel. The newly designed system has the potential to discover metallic tags attached to the bowel mucosa for precise intraoperative laparoscopic location of digestive tumors. Further work is in progress to increase the sensitivity and detection range of the system in order to make it fully compatible with the clinical use.

Computer vision for total laparoscopic hysterectomy

INTRODUCTION

Laparoscopic surgery is widely performed in various surgical fields, but this technique requires time for surgeons to master. However, at the same time, there are many advantages in visualizing the operative field through a camera. In other words, we can visualize what we cannot see with our own eyes by using augmented reality and computer vision. Therefore, we investigated the possibilities and usefulness of computer vision in total laparoscopic hysterectomy.

METHODS

This study was approved by the Mitsui Memorial Hospital ethics committee. Patients who underwent total laparoscopic hysterectomy at Mitsui Memorial Hospital from January 2015 to December 2015 were enrolled. We evaluated 19 cases in which total laparoscopic hysterectomy was performed by the same operator and assistant. We used the Open Source Computer Vision Library for computer vision analysis. The development platform used in this study was a computer operating on Mac OS X 10.11.3.

RESULTS

We created panoramic images by matching features with the AKAZE algorithm. Noise reduction methods improved haziness caused by using energy devices. By abstracting the color of the suture string, we succeeded in abstracting the suture string from movies. We could not achieve satisfactory results in detecting ureters, and we expect that creative ideas for ureter detection may arise from collaborations between surgeons and medical engineers.

CONCLUSIONS

Although this was a preliminary study, the results suggest the utility of computer vision in assisting laparoscopic surgery.

The Feasibility and Safety of Preoperative Fluorescence Marking with Indocyanine Green (ICG) in Laparoscopic Gastrectomy for Gastric Cancer

BACKGROUND

Securing the surgical margin is the most essential and important task in curative surgery. However, it is difficult to accurately identify the tumor location during laparoscopic surgery for gastric cancer, and existing methods, such as preoperative endoscopic marking with tattooing and clipping, have multiple disadvantages.

AIMS

We investigated the feasibility and safety of indocyanine green (ICG) fluorescence marking for determining the tumor location during laparoscopic gastrectomy.

METHODS

We retrospectively analyzed preoperative and perioperative data from consecutive patients with gastric cancer undergoing planned laparoscopic distal gastrectomy. Data was maintained in a prospectively compiled surgical database, and patients were categorized into ICG (n = 84) or non-ICG (n = 174) groups based on whether they underwent preoperative endoscopic mucosal ICG injection. One-to-one propensity score matching (PSM) was performed to compare outcomes between the two groups.

RESULTS

We included 84 patient pairs after PSM, and there were no significant differences in preoperative patient characteristics. The ICG group had shorter procedure time (p < 0.001), lower estimated blood loss (p = 0.005), and significantly shorter postoperative hospital stay (p < 0.001). Positive resection margins were confirmed in five cases (6.0%) in the non-ICG group, whereas there were none in the ICG group (p = 0.008). Real-time confirmation was possible during laparoscopy, and the injected ICG did not affect the surgical procedure or result in adverse events.

CONCLUSION

ICG fluorescence imaging is feasible and safe and can potentially be used as a tumor-marking agent for determining the surgical resection line.

Real-time detection system for tumor localization during minimally invasive surgery for gastric and colon cancer removal: In vivo feasibility study in a swine model

BACKGROUND AND OBJECTIVES

During minimally invasive surgery (MIS), it is impossible to directly detect marked clips around tumors via palpation. Therefore, we developed a novel method and device using Radio Frequency IDentification (RFID) technology to detect the position of clips during minimally invasive gastrectomy or colectomy.

METHODS

The feasibility of the RFID-based detection system was evaluated in an animal experiment consisting of seven swine. The primary outcome was to successfully detect the location of RFID clips in the stomach and colon. The secondary outcome measures were to detect time (time during the intracorporeal detection of the RFID clip), and accuracy (distance between the RFID clip and the detected site).

RESULTS

A total of 25 detection attempts (14 in the stomach and 11 in the colon) using the RFID antenna had a 100% success rate. The median detection time was 32.5 s (range, 15-119 s) for the stomach and 28.0 s (range, 8-87 s) for the colon. The median detection distance was 6.5 mm (range, 4-18 mm) for the stomach and 6.0 mm (range, 3-13 mm) for the colon.

CONCLUSIONS

We demonstrated favorable results for a RFID system that detects the position of gastric and colon tumors in real-time during MIS.