Ureteral Injury During Colorectal Surgery: Two Case Reports and a Literature Review

A case of bladder and pelvic dead space inflammation successfully treated with endoscopic ultrasound drainage

Key Clinical Message

Interventional endoscopic ultrasound (EUS) is effective not only for biopsy, but also for abscess drainage. We report the first use of EUS to drain inflammation of the bladder and pelvic dead space through the ileal conduit. EUS-guided drainage is effective in treating postoperative abscesses and should be employed more routinely.

Abstract

The patient was a 77-year-old man with a vesicoureteral fistula. An ileal conduit was placed after abdominoperineal resection and partial bladder resection for local, postoperative recurrence of rectal cancer. During postoperative chemotherapy, the patient developed a high-grade fever and after a thorough examination, he was diagnosed with bladder and pelvic dead-space inflammation. All urine flowed through the ileal conduit, and it was assumed that secretions from the residual bladder and prostate gland had accumulated in the bladder and pelvic cavity, resulting in infection. A transcutaneous drain was inserted through the perineum and the infection was controlled, but it flared up again after the drain was removed. We concluded that long-term drainage was necessary and successfully controlled the infection by placing a plastic stent through the ileal conduit into the bladder and pelvic dead space under ultrasound endoscopy. This is the first report of ultrasound endoscopic drainage of an abscess through the ileal conduit.

Pudexacianinium (ASP5354) chloride for ureter visualization in participants undergoing laparoscopic, minimally invasive colorectal surgery

BACKGROUND

Intraoperative ureteral injury, a serious complication of abdominopelvic surgeries, can be avoided through ureter visualization. Near-infrared fluorescence imaging offers real-time anatomical visualization of ureters during surgery. Pudexacianinium (ASP5354) chloride is an indocyanine green derivative under investigation for intraoperative ureter visualization during colorectal or gynecologic surgery in adult and pediatric patients.

METHODS

In this phase 2 study (NCT04238481), adults undergoing laparoscopic colorectal surgery were randomized to receive one intravenous dose of pudexacianinium 0.3 mg, 1.0 mg, or 3.0 mg. The primary endpoint was successful intraoperative ureter visualization, defined as observation of ureter fluorescence 30 min after pudexacianinium administration and at end of surgery. Safety and pharmacokinetics were also assessed.

RESULTS

Participants received pudexacianinium 0.3 mg (n = 3), 1.0 mg (n = 6), or 3.0 mg (n = 3). Most participants were female (n = 10; 83.3%); median age was 54 years (range 24-69) and median BMI was 29.3 kg/m2 (range 18.7-38.1). Successful intraoperative ureter visualization occurred in 2/3, 5/6, and 3/3 participants who received pudexacianinium 0.3 mg, 1.0 mg, or 3.0 mg, respectively. Median intensity values per surgeon assessment were 1 (mild) with the 0.3-mg dose, 2 (moderate) with the 1.0-mg dose, and 3 (strong) with the 3.0-mg dose. A correlation was observed between qualitative (surgeon's recognition/identification of the ureter during surgery) and quantitative (video recordings of the surgeries after study completion) assessment of fluorescence intensity. Two participants experienced serious adverse events, none of which were drug-related toxicities. One adverse event (grade 1 proteinuria) was related to pudexacianinium. Plasma pudexacianinium concentrations were dose-dependent and the mean (± SD) percent excreted into urine during surgery was 22.3% ± 8.0% (0.3-mg dose), 15.6% ± 10.0% (1.0-mg dose), and 39.5% ± 12.4% (3.0-mg dose).

CONCLUSIONS

In this study, 1.0 and 3.0 mg pudexacianinium provided ureteral visualization for the duration of minimally invasive, laparoscopic colorectal procedures and was safe and well tolerated.

Simultaneous, Multi-Channel, Near-Infrared Fluorescence Visualization of Mesenteric Lymph Nodes Using Indocyanine Green and Methylene Blue: A Demonstration in a Porcine Model

Near-infrared fluorescence (NIRF) image-guided surgery is a useful tool that can help reduce perioperative complications and improve tissue recognition. Indocyanine green (ICG) dye is the most frequently used in clinical studies. ICG NIRF imaging has been used for lymph node identification. However, there are still many challenges in lymph node identification by ICG. There is increasing evidence that methylene blue (MB), another clinically applicable fluorescent dye, can also be useful in the intraoperative fluorescence-guided identification of structures and tissues. We hypothesized that MB NIRF imaging could be used for lymph node identification. The aim of this study was to evaluate the feasibility of intraoperative lymph node fluorescence detection using intravenously (IV) administered MB and compare it to ICG via a camera that has two dedicated near-infrared (NIR) channels. Three pigs were used in this study. ICG (0.2 mg/kg) was administered via a peripheral venous catheter followed by immediate administration of MB (0.25 mg/kg). NIRF images were acquired as video recordings at different time points (every 10 min) over an hour using the QUEST SPECTRUM^® 3 system (Quest Medical Imaging, Middenmeer, The Netherlands), which has two dedicated NIR channels for simultaneous intraoperative fluorescence guidance. The 800 nm channel was used to capture ICG fluorescence and the 700 nm channel was used for MB. The target (lymph nodes and small bowel) and the background (vessels-free field of the mesentery) were highlighted as the regions of interest (ROIs), and corresponding fluorescence intensities (FI) from these ROIs were measured. The target-to-background ratio (TBR) was then computed as the mean FI of the target minus the mean FI of the background divided by the mean FI of the background. In all included animals, a clear identification of lymph nodes was achieved at all time points. The mean TBR of ICG in lymph nodes and small bowel was 4.57 ± 1.00 and 4.37 ± 1.70, respectively for the overall experimental time. Regarding MB, the mean TBR in lymph nodes and small bowel was 4.60 ± 0.92 and 3.27 ± 0.62, respectively. The Mann-Whitney U test of the lymph node TBR/small bowel TBR showed that the TBR ratio of MB was statistically significantly higher than ICG. The fluorescence optical imaging technology used allows for double-wavelength assessment. This feasibility study proves that lymph nodes can be discriminated using two different fluorophores (MB and ICG) with different wavelengths. The results suggest that MB has a promising potential to be used to detect lymphatic tissue during image-guided surgery. Further preclinical trials are needed before clinical translation.

Trends and benefits of prophylactic ureter catheters in the era of minimally invasive surgery

BACKGROUND

The recent spike in ureter injury (UI) amidst the rise of minimally invasive surgery (MIS) has focused attention on the propriety of prophylactic ureter catheters (PUCs) for abdominopelvic operations.

METHODS

A retrospective review of PUCs for rectal cancer resection following neoadjuvant therapy, combined with a comprehensive literature review.

RESULTS

There were zero UI in the current study. Literature review revealed a nationwide spike in PUCs in the last 30 years, dependent on operation: 1) colorectal resection-increased from 1.1% to 4.4%, 2) sigmoid colectomy for diverticulitis-increased from 6.7% to 16.3%. This 2-4 fold increase parallels the rise of MIS: 15 of the 20 latest studies (75%) either combined open operations and MIS (4 studies) or focused solely on MIS (11 studies). Medial-to-lateral dissection identified as a UI risk factor. Only 20-30% of UI identified intraoperatively.

CONCLUSIONS

Intraoperative UI is missed in 70-80% of cases. The prevention, identification, ease of ureter repair, and net decrease in operative time support the use of PUCs. Medial-to-lateral dissection is identified as a potential contributing factor to UI.

Nerve autofluorescence in near-ultraviolet light markedly enhances nerve visualization in vivo

BACKGROUND

During surgery, surgeons must accurately localize nerves to avoid injuring them. Recently, we have discovered that nerves fluoresce in near-ultraviolet light (NUV) light. The aims of the current study were to determine the extent to which nerves fluoresce more brightly than background and vascular structures in NUV light, and identify the NUV intensity at which nerves are most distinguishable from other tissues.

METHODS

We exposed sciatic nerves within the posterior thigh in five 250-300 gm Wistar rats, then observed them at four different NUV intensity levels: 20%, 35%, 50%, and 100%. Brightness of fluorescence was measured by fluorescence spectroscopy, quantified as a fluorescence score using Image-J software, and statistically compared between nerves, background, and both an artery and vein by unpaired Student's t tests with Bonferroni adjustment to accommodate multiple comparisons. Sensitivity, specificity, and accuracy were calculated for each NUV intensity.

RESULTS

At 20, 35, 50, and 100% NUV intensity, fluorescence scores for nerves versus background tissues were 117.4 versus 40.0, 225.8 versus 88.0, 250.6 versus 121.4, and 252.8 versus 169.4, respectively (all p < 0.001). Fluorescence scores plateaued at 50% NUV intensity for nerves, but continued to rise for background. At 35%, 50%, and 100% NUV intensity, a fluorescence score of 200 was 100% sensitive, specific, and accurate identifying nerves. At 100 NUV intensity, artery and vein scores were 61.8 and 60.0, both dramatically lower than for nerves (p < 0.001).

CONCLUSIONS

At all NUV intensities ≥ 35%, a fluorescence score of 200 is 100% accurate distinguishing nerves from other anatomical structures in vivo.

Intraoperative use of indocyanine green fluorescence imaging in rectal cancer surgery: The state of the art

Indocyanine green (ICG) fluorescence imaging is widely used in abdominal surgery. The implementation of minimally invasive rectal surgery using new methods like robotics or a transanal approach required improvement of optical systems. In that setting, ICG fluorescence optimizes intraoperative vision of anatomical structures by improving blood and lymphatic flow. The purpose of this review was to summarize all potential applications of this upcoming technology in rectal cancer surgery. Each type of use has been separately addressed and the evidence was investigated. During rectal resection, ICG fluorescence angiography is mainly used to evaluate the perfusion of the colonic stump in order to reduce the risk of anastomotic leaks. In addition, ICG fluorescence imaging allows easy visualization of organs such as the ureter or urethra to protect them from injury. This intraoperative technology is a valuable tool for conducting lymph node dissection along the iliac lymphatic chain or to better identifying the rectal dissection planes when a transanal approach is performed. This is an overview of the applications of ICG fluorescence imaging in current surgical practice and a synthesis of the results obtained from the literature. Although further studies are need to investigate the real clinical benefits, these findings may enhance use of ICG fluorescence in current clinical practice and stimulate future research on new applications.

Kidney Autotransplantation for Treatment of Ureteric Obstruction: A Case Report and Brief Review of the Literature

Autologous kidney transplantation is a relatively rare procedure that has been used as an alternative treatment for a variety of complex genitourinary problems, in particular for the treatment of complex proximal ureteral strictures. In this case report, a 47-year-old male, who had undergone a living donor nephrectomy 14 years earlier, presented with episodes of acute kidney injury on chronic kidney disease. He was found to have a complex proximal ureter stricture of his solitary right kidney. He underwent nephrectomy with subsequent autotransplantation of the kidney into the right iliac fossa. His renal function improved significantly after surgery. Renal autotransplantation may be considered for the management of proximal ureteral obstruction when alternative options are contraindicated.

Intraoperative complications during laparoscopic total mesorectal excision

Intraoperative complication during laparoscopic mesorectal excision for rectal cancer is a common complication occurring in 11% to 15% of the cases. They are probably underestimated because not systematically reported. The most frequent intraoperative complications are haemorrhage (3-7%), tumour perforation (1-4%), bowel injury (1-3%), ureter injury (1%), urogenital injury (2%), other organ injury (<1%), and anastomotic complications (1%). The mechanisms, management and prevention of vascular port injury, inferior mesenteric artery bleeding, small bowel and colon perforation, ureteral and urethral injury, pelvic nerve damage, tumour perforation and anastomotic failure are described. This review underlines the necessity to prevent intraoperative complication to avoid operative death and severe side-effects.

Nerve autofluorescence in near-ultraviolet light markedly enhances nerve visualization in vivo

BACKGROUND

During surgery, surgeons must accurately localize nerves to avoid injuring them. Recently, we have discovered that nerves fluoresce in near-ultraviolet light (NUV) light. The aims of the current study were to determine the extent to which nerves fluoresce more brightly than background and vascular structures in NUV light, and identify the NUV intensity at which nerves are most distinguishable from other tissues.

METHODS

We exposed sciatic nerves within the posterior thigh in five 250-300 gm Wistar rats, then observed them at four different NUV intensity levels: 20%, 35%, 50%, and 100%. Brightness of fluorescence was measured by fluorescence spectroscopy, quantified as a fluorescence score using Image-J software, and statistically compared between nerves, background, and both an artery and vein by unpaired Student's t tests with Bonferroni adjustment to accommodate multiple comparisons. Sensitivity, specificity, and accuracy were calculated for each NUV intensity.

RESULTS

At 20, 35, 50, and 100% NUV intensity, fluorescence scores for nerves versus background tissues were 117.4 versus 40.0, 225.8 versus 88.0, 250.6 versus 121.4, and 252.8 versus 169.4, respectively (all p < 0.001). Fluorescence scores plateaued at 50% NUV intensity for nerves, but continued to rise for background. At 35%, 50%, and 100% NUV intensity, a fluorescence score of 200 was 100% sensitive, specific, and accurate identifying nerves. At 100 NUV intensity, artery and vein scores were 61.8 and 60.0, both dramatically lower than for nerves (p < 0.001).

CONCLUSIONS

At all NUV intensities ≥ 35%, a fluorescence score of 200 is 100% accurate distinguishing nerves from other anatomical structures in vivo.