Near-infrared fluorescent solid material for visualizing indwelling devices implanted for medical use

Development of a novel fluorescent gauze using indocyanine green

Gauzes are used in various ways, including wiping blood, compressing organs, and as markers during surgery. However, losing gauze during surgery can lead to pieces being left inside the body, causing time-consuming searches and unnecessary radiation exposure. To address this, we developed a fluorescent gauze using indocyanine green (ICG), which fluoresces under near-infrared (NIR) light. This study aimed to evaluate the fluorescence intensity (FI) of the gauze and confirm its fluorescence in a porcine abdominal cavity. We dissolved 25 mg of ICG in 10 ml of glycerol, ethanol, distilled water, and 5% bovine serum albumin, then diluted each solution 5- to 106-fold with distilled water. The gauze was dyed using these solutions. A rigid laparoscope observed the fluorescent gauze in a dark room under NIR light, and FI was measured. The gauze treated with a 100-fold dilution of each ICG dyestuff showed the strongest fluorescence. This gauze was then placed in a pig's abdominal cavity and observed under NIR light, demonstrating that the fluorescence could penetrate two or three layers of the mesentery. Our fluorescent gauze, confirmed both ex vivo and in vivo, should be manufactured for clinical use and further validated for its utility.

A novel vaginal manipulator for identifying vaginal canal separation line by visible and near-infrared transillumination light: PHARUS Pipe

INTRODUCTION

In total laparoscopic hysterectomy, a uterine manipulator with transillumination functionality is often employed as an instrument to visualize the vaginal canal demarcation line. However, the utilization of this device necessitates an external white light source and a fiber optic cable. In this study, we developed a prototype vaginal manipulator (PHARUS Pipe) with a simpler configuration to visualize the vaginal canal separation line.

METHODS

The PHARUS Pipe is constructed from a pipe, an annular array of chip-type light-emitting diodes (LEDs) with a wavelength of warm-white and near-infrared light, and a handle. The pipe, with an outer diameter of 30 mm at the tip and a wall thickness of 3 mm, was molded using a light-guiding resin. The annular LED array was positioned on the end face of the handle side of the pipe, and a battery was integrated into the handle. The pipe was designed with an external surface to provide optimal light emission at the tip in a radial direction, i.e., away from the center of the pipe. The visibility of the transillumination passing through a 3-4 mm thick vaginal wall of porcine uterovaginal specimens was evaluated using a near-infrared compatible laparoscopic imaging system.

RESULTS

The position of the tip of the PHARUS Pipe was clearly delineated through the vaginal wall by warm-white and near-infrared transillumination light. Compared with warm-white light, near-infrared light required less current for successful visualization.

CONCLUSIONS

The present results suggest the possibility of identifying the human vaginal canal separation line using the PHARUS Pipe.

Utility and challenges of ureteral visualization using a fluorescent ureteral catheter in high risk surgeries for colorectal cancer

BACKGROUND

Ureteral injury occurs in 0.3-1.5% of colorectal cancer surgeries. Devices to visualize the ureteral course and avoid ureteral injury are required for minimally invasive surgery (MIS). The NIRC™ fluorescent ureteral catheter (FUC) is a versatile ureteral visualization device currently available in Japan that can be used in combination with a variety of laparoscopic and robotic systems. In this study, we examined the outcomes of high-risk patients who underwent colorectal cancer surgery with FUC insertion.

METHODS

One hundred forty-one patients who underwent MIS for colorectal cancer and colorectal cancer recurrence at our institute between January 2021 and May 2024 underwent preoperative FUC insertion because of the high risk of ureteral injury and surgical difficulty. For these patients, patient background data and short-term outcomes were examined. The results are expressed as the median and interquartile range.

RESULTS

Age, 70 [60-78]; M:F(n), 84:57; BMI, 22.1 [19.7-24.7]; T4 (TNM classification), 52 cases (36.9%); preoperative intestinal obstruction, 45 cases (31.9%); abscess formation, 30 cases (21%); surgical history, 70 cases (50%); recurrent cancer, 14 cases (9.9%); preoperative chemo-radiotherapy, 28 cases (19.9%); time required for FUC insertion, 12 [9-19] minutes; operation time, 412 [309-552] minutes; blood loss, 10 [5-30] ml; open conversion, 0 cases; postoperative hospitalization, 12 [9-17.5]; circumferential resection margins < 1 mm (rectal surgery), 4/87 cases (4.6%); comorbidities, 0 ureteral injury, 1 urethral injury during FUC insertion (0.7%) and 16 CD Grade 3 or higher cases (11%).

CONCLUSIONS

FUC may improve the safety of MIS and reduce blood loss in addition to preventing ureteral injury and is expected to have oncological advantages for ensuring the margin of the tumor without fear of ureteral injury. However, the time required for and complications associated with FUC are challenging. New methods for less invasive and easier ureteral visualization may be needed.

Diagnostic Performance of Near-Infrared Fluorescent Marking Clips in Laparoscopic Gastrectomy

INTRODUCTION

Accurate tumor localization and resection margin acquisition are essential in gastric cancer surgery. Preoperative placement of marking clips in laparoscopic gastrectomy as well as intraoperative gastroscopy can be used for gastric cancer surgery. However, these procedures are not available at all institutions. We conducted a prospective clinical trial to investigate the diagnostic performance of near-infrared fluorescent clips (ZEOCLIP FS) in laparoscopic gastrectomy.

MATERIALS AND METHODS

Patients with gastric cancer or neuroendocrine tumor in whom laparoscopic distal, pylorus-preserving, or proximal gastrectomy was planned were enrolled (n = 20) in this study. Fluorescent clips were placed proximal and/or distal to the tumor via gastroscopy on the day before surgery. During surgery, the clips were detected using a fluorescent laparoscope, and suturing was performed where fluorescence was detected. The clip locations were then confirmed via gastroscopy, and the stomach was transected. The primary endpoint was the detection rate of the marking clips using fluorescence, and the secondary endpoints were complications and distance between the clips and stitches.

RESULTS

Among the 20 patients enrolled, distal and pylorus-preserving gastrectomies were performed in 18 and 2 patients, respectively. All clips were detected in 15 patients, indicating a detection rate of 75.0% (90% confidence interval: 54.4%-89.6%). Furthermore, no complications related to the clips were observed. The median distance between the clips and stitches was 5 (range, 0-10) mm.

CONCLUSIONS

We report the feasibility and safety of preoperative placement and intraoperative detection of near-infrared fluorescent marking clips in laparoscopic gastrectomy.

A novel Foley catheter made of high-intensity near-infrared fluorescent silicone rubber for image-guided surgery of lower rectal cancer

BACKGROUND

Urethral injury occurs in 1-6 % of male cases during minimally invasive surgery of lower rectal cancer. A Foley catheter emitting near-infrared (NIR) fluorescence of sufficient intensity has been expected to locate the urethra during image-guided surgery. Although it has been difficult to impart NIR fluorescent properties to biocompatible thermosetting polymers, we have recently succeeded in developing a NIR fluorescent compound for silicone rubber and a NIR fluorescent Foley catheter (HICARL). Here, we evaluated its NIR fluorescence properties and visibility performance using porcine anorectal isolation specimens.

METHODS

The HICARL catheter was made of a mixture of solid silicone rubber and a NIR fluorescent compound that emits fluorescence with a wavelength of 820-880 nm, while a conventional transparent Foley catheter was made of solid silicone rubber only. As a standard for comparison of the intensity of NIR fluorescence, a transparent Foley catheter the lumen of which was filled with a mixture of indocyanine green (ICG) and human plasma was used. As a comparison to assess the visibility performance of the HICARL catheter, a transparent Foley catheter into which a commercially available NIR fluorescent polyurethane ureteral catheter (NIRC) was placed was used.

RESULTS

A NIR fluorescence quantitative imaging analysis revealed that the Foley-NIRC catheter and the HICARL catheter emitted 3.42 ± 0.42 and 6.43 ± 0.07 times more fluorescence than the Foley-ICG catheter, respectively. The location of the HICARL catheter placed in the anorectum with a wall thickness of 3.8 ± 0.1 mm was clearly delineated in its entirety by NIR fluorescence, while that of the Foley-NIRC catheter was faintly or only partially visible.

CONCLUSIONS

The HICARL catheter emitting NIR fluorescence of sufficient intensity is a promising and easy-to-use tool for urethral visualization during image-guided surgery of lower rectal cancer.

2023 WSES guidelines for the prevention, detection, and management of iatrogenic urinary tract injuries (IUTIs) during emergency digestive surgery

Iatrogenic urinary tract injury (IUTI) is a severe complication of emergency digestive surgery. It can lead to increased postoperative morbidity and mortality and have a long-term impact on the quality of life. The reported incidence of IUTIs varies greatly among the studies, ranging from 0.3 to 1.5%. Given the high volume of emergency digestive surgery performed worldwide, there is a need for well-defined and effective strategies to prevent and manage IUTIs. Currently, there is a lack of consensus regarding the prevention, detection, and management of IUTIs in the emergency setting. The present guidelines, promoted by the World Society of Emergency Surgery (WSES), were developed following a systematic review of the literature and an international expert panel discussion. The primary aim of these WSES guidelines is to provide evidence-based recommendations to support clinicians and surgeons in the prevention, detection, and management of IUTIs during emergency digestive surgery. The following key aspects were considered: (1) effectiveness of preventive interventions for IUTIs during emergency digestive surgery; (2) intra-operative detection of IUTIs and appropriate management strategies; (3) postoperative detection of IUTIs and appropriate management strategies and timing; and (4) effectiveness of antibiotic therapy (including type and duration) in case of IUTIs.

Preoperative fluorescent clip marking vs. India ink tattooing for tumor identification during colorectal surgery

PURPOSE

Identifying tumor location is important in colorectal tumor resection. Preoperative endoscopic India ink marking is a widespread practice, but local injection of ink is an unstable procedure. Although it is often invisible, the ink may be sprayed into the peritoneal cavity and contaminate the surgical field. At our hospital, we introduced fluorescent clip marking (FCM) using the Zeoclip FS®, an endoscopic clip developed using near-infrared fluorescent resin. We tested the usefulness of FCM by retrospectively comparing cases in which FCM was used with cases in which conventional ink marking was used.

METHODS

We enrolled 305 patients with colorectal tumors who underwent colorectal surgery after preoperative marking from January 2017 to April 2022. We classified the patients into the FCM group (86 patients) and the India ink tattoo group (219 patients). Endoscopic marking was completed in the FCM group by the day before surgery, and fluorescence was evaluated during surgery with a fluorescent laparoscopic system. Patient backgrounds, marking visibility, adverse effects, and early postoperative results were retrospectively compared between groups.

RESULTS

Marking was visually confirmed in 80 patients in the FCM group (93.02%) and in 166 patients in the India ink tattoo group (75.80%) (p = 0.0006). In the group with India ink tattoos, contamination of the surgical field was observed in seven cases (3.20%). No adverse events were observed in the FCM group.

CONCLUSION

In colorectal surgery, FCM provides better visibility than the conventional India ink tattooing method and is a simple and safe marking method.

CLINICAL TRIAL REGISTRATION

Examination of fluorescence navigation for laparoscopic colorectal cancer surgery. Research Ethics Committee of the Kawaguchi Municipal Medical Center (Saitama, Japan) approval number: 2020-3. https://kawaguchi-mmc.org/wp-content/uploads/clinicalresearch-r02.pdf .

Fluorescent ureteral catheters in laparoscopic surgery for rectal cancer with invasion of the uterus: A case report

Introduction

Resection of the uterus is required in some cases of colorectal cancer with invasion of the uterus. Localisation of the ureters to prevent ureteral injuries is important during resection of advanced colorectal cancer and combined resection of the uterus.

Case presentation

We report a case of a woman in her 80s with rectal cancer with invasion of the uterus. She presented with appetite loss and lower abdominal pain. She was hospitalised after being diagnosed with intestinal obstruction due to rectal cancer. Colonoscopy revealed a tumor involving 100% of the circumference of the rectosigmoid colon, and imaging showed rectal cancer with invasion of the uterus and a giant uterine fibroid. Fluorescent ureteral catheters were placed bilaterally under cystoscopy, and laparoscopic anterior rectal resection, combined hysterectomy, and bilateral adnexectomy were performed 1 day later. Near-infrared visualisation of these catheters enabled safe release of the surrounding tissues from the uterus.

Clinical discussion

Surgical treatment of rectal cancer with invasion of the uterus is not standardised and requires more complicated procedures, which are associated with a high risk of ureteral injury. Fluorescent ureteral catheters allow visualisation of the course of the ureters without releasing them, thereby enabling safe surgery.

Conclusion

In fluorescence-guided surgery for rectal cancer, fluorescent ureteral catheters are particularly useful in patients with suspected invasion of other organs.

•T4b rectal cancer has higher risk of ureteral injury.

•Fluorescent ureteral catheter is visualised clearly via near-infrared light.

•Fluorescent ureteral catheter can be useful during surgery for T4b rectal cancer.

Intraoperative Tumor Identification During Laparoscopic Distal Gastrectomy: a Novel Fluorescent Clip Marking Versus Metal Clip Marking and Intraoperative Gastroscope

BACKGROUND

In complete laparoscopic distal gastrectomy, the gastric resection line is difficult to determine due to a lack of tactile sensation. The use of intraoperative gastroscopy and intraoperative radiography has been reported, but the burden on personnel and technical complexity present impediments. In our department, based on lesion extent determined with preoperative gastroscopy, a fluorescent clip is used to mark the oral side of the lesion, which is resected after confirmation with a fluorescent laparoscopic system. In this study, we investigated the efficacy of fluorescent clip marking (FCM) in achieving an accurate resection line and reducing the operative time.

METHODS

Fifty-six patients with gastric cancer who underwent complete laparoscopic distal gastrectomy from January 2018 to March 2021 were divided into two groups: the FCM group (n = 32) and the conventional metal clip marking and intraoperative gastroscopy (MCMG) group (n = 24). Short-term outcomes, including the resection margins, gastric resection time, and operative time, were compared and examined.

RESULTS

The fluorescent clips were visible in all cases, and all stumps were negative according to permanent preparations. The operative times for FCM and MCMG were 350 (216-533) vs. 373.5 (258-651) min, respectively, with no significant difference (p = 0.316), while the gastric resection times were 636.5 (321-2572) vs. 1457.5 (843-4973) s, respectively, and were significantly shorter in the FCM group (p < 0.0001).

CONCLUSIONS

FCM shortened the gastric resection time and could possibly shorten the operative time. FCM is feasible and safe and can potentially be used as a tumor-marking agent to determine accurate surgical resection lines.

CLINICAL TRIAL REGISTRATION

Examination of Gastric Cancer, Research Ethics Committee of the Kawaguchi Municipal Medical Centre (Saitama, Japan), approval number: 2019-33. https://kawaguchi-mmc.org/wp-content/uploads/clinicalresearch-r02.pdf.

A Novel Technique Using Fluorescent Ureteral Catheter and Flexible Ureteroscope for Safe Laparoscopic Fenestration of Lymphocele after Kidney Transplantation

Laparoscopic fenestration of a postrenal transplant lymphocele is associated with a risk of renal hilar vessel and ureteral injury. Consequently, determination of the incision line is difficult. We describe a case of a 73-year-old man with postrenal transplant lymphocele who underwent a laparoscopic fenestration. We report a surgical video containing a new technique of laparoscopic fenestration using a fluorescent ureteral catheter in combination with a flexible ureteroscope. The combination of a fluorescent ureteral catheter and flexible ureteroscope during surgery enabled us to determine the incision line safely and accurately. Intraoperative real-time visualization of the lymphocele and ureter using a fluorescent ureteral catheter and a flexible ureteroscope is safer than conventional methods for laparoscopic fenestration. To the best of our knowledge, this is the first report of this novel technique.

A case in which a near-infrared ray catheter (NIRC) was effectively applied in laparoscopic sigmoidectomy for a sigmoidovesical fistula

A 40-year-old man visited the hospital for a refractory urinary tract infection. A sigmoidovesical fistula resulting from a sigmoidovesical diverticulum was diagnosed, and laparoscopic surgery was performed. To avoid ureteral injury during surgery for highly advanced cancer and inflammatory diseases, a ureteral stent is generally placed before the procedure. However, in this case, surgery was performed using a near-infrared ray catheter (NIRC), which emits fluorescence when irradiated with near-infrared light. By clearly observing the pathway of the ureter via near-infrared light, the integrity of the ureter could be preserved, and sigmoidectomy was safely performed. The visual navigation of the ureter with NIRC was especially useful during surgery for a colovesical fistula with marked surrounding inflammatory changes and a high risk of ureteral damage.

Fluorescence ureteral navigation during laparoscopic surgery for clinically suspected stage T4 colorectal cancer: A cohort study

BACKGROUND

Approximately 15% of patients with colorectal cancer present with locally advanced tumors (T4 stage). Laparoscopic surgery for stage T4 disease has not yet been established. The near-infrared ray catheter fluorescent ureteral catheter (NIRFUC) is a new device that uses near-infrared fluorescence resin. We examined the utility of fluorescence ureteral navigation (FUN) with the NIRFUC during laparoscopic surgery for stage T4 colorectal cancer.

MATERIALS AND METHODS

Patients with stage T4 colorectal cancer (n = 143, from January 2017 to March 2021) were divided into a T4FUN + group, in which the NIRFUC was used (n = 21), and a T4FUN- group, in which the NIRFUC was not used (n = 122). Short-term outcomes were compared between the groups. Next, the laparoscopic surgery rate and incidence of ureteral injury from January 2017 to March 2021 were compared between the T4FUN- group and the non-stage T4FUN- group (n = 434, from January 2017 to March 2021), in which fluorescence ureter navigation was not used.

RESULTS

Rectal cancer, stage T4b disease, and invasion into the urinary tract were observed more often in the T4FUN + group than in the T4FUN- group. In the comparisons of the T4FUN + versus T4FUN- groups, the operative time was 398 (161-1090) vs. 256 (93-839) minutes, the blood loss was 10 (1-710) vs. 25 (0-1360) ml, and the ratio of laparoscopic surgery to open surgery was 21:0 vs. 79:43. Postoperative complications (Clavien-Dindo grade ≥ III) were present in 2 (10%; 0 ureteral injury) patients in the T4FUN + group and 13 (11%; 2 ureteral injury) patients in the T4FUN- group. In the T4FUN + group, the operative time was longer (p < 0.0001), but the laparoscopic ratio was higher (p = 0.0002), and the blood loss volume and incidence of ureteral injury tended to be lower. In the comparisons of the T4FUN- versus non-stage T4FUN- groups, the ratio of laparoscopic surgery to open surgery was 79:43 vs. 384:50, the incidence of open conversion was 8 (6.6%) vs. 15 (3.5%), and the incidence of ureteral injury was 2 (1.6%) vs. 0 (0%). In the T4FUN- group, the open surgery rate (<0.0001), open conversion rate (p = 0.0205) and incidence of ureteral injury (p = 0.0478) were high, with a significant difference observed between the groups.

CONCLUSION

Patients with stage T4 disease have an increased risk of ureteral injury and are more likely to be converted to open surgery. FUN can help to safely increase the laparoscopic surgery rate while safely visualizing the ureter. FUN is recommended for laparoscopic surgery in patients with stage T4 colorectal cancer.

CLINICAL TRIAL REGISTRATION

Examination of fluorescence navigation for laparoscopic colorectal cancer surgery; Research Ethics Committee of the Kawaguchi Municipal Medical Center (Saitama, Japan) approval number: 2020-3. https://kawaguchi-mmc.org/wp-content/uploads/clinical research-r02.pdf.

New Technique of Laparoscopic Paraaortic Lymph Node Dissection for Colorectal Cancer Using Fluorescence Navigation

BACKGROUND/AIM

According to limited current reports, therapeutic paraaortic lymph node (PALN) dissection with intensive combined therapy for colorectal cancer improves prognosis in select patients. Laparoscopic PALN dissection is a difficult technique that has not yet been established. We applied this procedure using an intraoperative fluorescence navigation technique with a near-infrared ray catheter (NIRC™) fluorescent ureteral catheter (NIRFUC).

PATIENTS AND METHODS

We evaluated the utility of laparoscopic fluorescence navigation and the short-term outcomes of 6 patients undergoing laparoscopic PALN dissection.

RESULTS

There were 3 surgeries for synchronous metastasis and 3 surgeries for recurrent metastasis. The mean surgical duration, blood loss, and postoperative hospital stay were 677 (range=518-1,090) min, 7.5 (range=3-1,600) ml, and 14 (range=9-33) days, respectively. Postoperative complications (Clavien-Dindo grade >III) occurred in 1 case.

CONCLUSION

Dissection around the ureter was navigated with a NIRFUC. Fluorescence ureteral navigation facilitated completion of the complex laparoscopic PALN dissection procedure.

Fluorescence vessel and ureter navigation during laparoscopic lateral lymph node dissection

BACKGROUND

Lateral lymph node metastasis in lower rectal cancer is considered a local disease in Japan, and guidelines suggest lateral lymph node dissection (LLND). However, laparoscopic procedures are relatively difficult. The ureter and hypogastric fascia must be dissected from the vesicohypogastric fascia to preserve the autonomic nerve and ureter. Additionally, lymph node dissection around the internal iliac artery is complex because many patterns of branching from the internal iliac artery exist. We investigated the utility of fluorescence ureter and vessel navigation using a near-infrared ray fluorescent ureteral catheter (NIRFUC) and indocyanine green (ICG).

METHODS

Fourteen patients who underwent laparoscopic LLND using fluorescence navigation were included. Eleven patients had rectal cancer, 1 had anal cancer, and 2 exhibited recurrence of rectal cancer. Eleven patients underwent NIRFUC insertion before surgery. Fluorescence vessel navigation (FVN) was performed with intraoperative ICG injections in 14 patients, with a total of 18 sides. The outcome measures were ureter navigation visibility, detection of the branch form from the internal iliac artery with FVN, differences between the fluorescence findings and anatomy of the internal iliac artery determined after LLND, and the surgical outcome.

RESULTS

In all 11 patients, the ureters were clearly identified as fluorescent before dissection around the ureter. FVN revealed the internal iliac, umbilical, and superior vesical arteries in all patients. The branch from the internal iliac artery according to the Adachi classification was revealed on 16 sides (89%). The time from intravenous ICG injection to fluorescence of the internal iliac artery was 38 (17-57) s. The time from intravenous injection to when the vessels were observed as fluorescent was 113 (65-661) s. No ureteral or vessel injuries occurred.

CONCLUSIONS

Fluorescence navigation of vessels and the ureter is feasible in laparoscopic LLND and has the potential to increase safety.

CLINICAL TRIAL REGISTRATION

Examination of fluorescence navigation for laparoscopic colorectal cancer surgery Research Ethics Committee of the Kawaguchi Municipal Medical Center (Saitama, Japan) approval number: 2020-3. https://kawaguchi-mmc.org/wp-content/uploads/clinicalresearch-r02.pdf.

Ureteral navigation using a fluorescent ureteral catheter during laparoscopic colorectal surgery

BACKGROUND

Ureteral injury is the most common urological complication of pelvic surgery, with a reported incidence during colon resection of 0.3-1.5%. Ureteral stenting is commonly performed preoperatively to prevent ureteral injury. Because tactile sensation is not reliable during laparoscopic surgery, the effect of the ureteral stent is considered limited. Recently, fluorescence imaging has been used in laparoscopic surgery. The Near-Infrared Ray Catheter (NIRC™) fluorescent ureteral catheter (NIRFUC) is a new catheter with built-in NIR fluorescent resin. This pilot study was performed to evaluate the utility of fluorescence ureteral navigation using the NIRFUC during laparoscopic colorectal surgery.

METHODS

We evaluated the intraoperative utility of the NIRFUC and the short-term outcomes in 20 patients treated with colorectal surgery at Kawaguchi Municipal Medical Center between February and July 2020. In all, 18 patients with malignant tumors and 2 patients with benign disease, i.e., a sigmoid colovesical fistula, were included. Ten patients developed preoperative intestinal obstruction. One patient experienced preoperative perforation. Nine patients developed preoperative peritumoral abscesses. Laparoscopic surgery was performed with the VISERA ELITE2 system.

RESULTS

In all cases, the ureters were very clearly identified as fluorescent without the need for dissection. In all cases, only a moment was required to identify the ureter by fluorescence observation. In all cases, R0 resection was performed. The mean surgical duration was 334 min (161-1014), the mean blood loss was 10 ml (1-500), and the mean postoperative hospital stay was 11 days (8-47). There were no cases of ureteral injury.

CONCLUSION

The NIRFUC was very clearly identified as fluorescent in a moment during surgery without dissection around the ureter. Fluorescence ureteral navigation using the NIRFUC may make colorectal surgery easier and facilitate completion of complex minimally invasive surgery, especially during surgery in patients with invasion of the surrounding tissue or a history of pelvic surgery or radiation.