Fluorescence-guided laparoscopic-assisted transabdominal intersphincteric resection for ultralow rectal cancer: report of a surgical technique

Introduction

Background

Colorectal cancer (CRC), which is ranked third among malignant tumors in incidence worldwide, represents a significant threat to patients’ survival and quality of life (1). Radical surgery with thorough lymph node (LN) dissection remains the mainstay multidisciplinary treatment for CRC (2). In addition to ensuring survival, organ and function preservation is increasingly becoming a concern of both surgeons and patients with CRC (3). In the past, patients with low rectal cancer could only receive abdominoperineal resection (APR) with permanent colostomy. However, in recent years, with the development of the intersphincteric resection (ISR) technique, organ preservation can be achieved even in those patients with ultralow rectal cancer (3).

Rationale

In ISR, the mesorectum needs to be completely isolated down to the pelvic floor until the intersphincteric space is opened (4). Due to the deep and narrow pelvic space, this technique is demanding, especially when performed via a conventional open approach. Fortunately, the advancement of laparoscopy has made it possible to operate in an accurate plane for low rectal cancer. Moreover, with the effect of visual amplification under laparoscopy, enhanced protection for neurovascular tissues has become achievable (5); however, the incidence of anastomotic leak (AL) increases after ISR due to the lower location.

Sufficient LN dissection is required in radical surgery to prevent residual tumor and decrease the risk of local recurrence. The relevant guidelines recommend that at least 12 LNs be harvested in CRC surgery for accurate staging (6). Prior to the development of real-time fluorescence, there was no intraoperative technique capable of detecting the remaining LNs. In recent years, fluorescence imaging has been increasingly adopted in CRC surgery for intraoperative navigation (7). Furthermore, fluorescence has been used to examine the blood supply to the anastomosis in real time, further decreasing the risk of AL (8).

Objective

We present the technique combining fluorescence navigation and laparoscopic-assisted transabdominal ISR for ultra-low rectal cancer (Video 1). In addition to organ preservation, this procedure may provide more thorough LN dissection while decreasing the risk of AL. We present this article in accordance with the SUPER reporting checklist (available at https://jgo.amegroups.com/article/view/10.21037/jgo-2025-642/rc).

Preoperative preparations and requirements

A minimally invasive surgery with curative intent was performed via a laparoscopic approach at The First Affiliated Hospital of the University of Science and Technology of China, a top grade 3A hospital in Anhui Province. The surgery was completed by S.L., who was an attending physician with more than 10 years’ experience in CRC surgery.

The male patient was 72 years old and had a body mass index (BMI) of 22.6 kg/m². He had a history of hypertension for 10 years but no previous abdominal surgery. At the time, his chief complaint was hematochezia lasting 1 month. The digital examination identified a rectal tumor, whose lower edge was located 4 cm distant from the anal verge. The clinical stage based on pelvic magnetic resonance imaging (MRI) was cT2N0M0 (the MRI imaging was showed in Figure S1). The preoperative examinations did not indicate any surgical contraindications. After a multidisciplinary team meeting, we decided to perform fluorescence-guided laparoscopic-assisted transabdominal ISR in the patient. About 24 hours before surgery, indocyanine green (ICG; 2.5 mg/mL) was injected into four sites of the submucosa layer around the tumor under colonoscopy.

The patient was required to drink 90 mL of oral solution consisting of sodium phosphates 12 hours before surgery and to have no excrement or fecal residue present before surgery. Following the administration of intratracheal anesthesia, urinary catheterization was performed. The patient was then placed in the lithotomy position with his right-side leg extended and head dropping. Laparoscopy equipment with a fluorescence system was placed at the caudal end, and the surgeon stood on the right side of the patient. Next, the ultrasonic coagulation and electrocoagulation systems were linked, and the liner and circular staplers were prepared for use. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for publication of this manuscript, the accompanying image, and the video. A copy of the written consent is available for review by the editorial office of this journal.

Step-by-step description

Abdominal exploration was first performed. No metastasis was found on the surface of the liver, mesentery, or peritoneum. The rectal tumor was not above the peritoneal reflection. Next, the fluorescence mode was initiated in laparoscopy, and a few small LNs were identified at the root of inferior mesenteric vessels.

We released the adhesion linking the sigmoid colon and lateral abdominal wall and dissected toward the cephalic side to reveal the left paracolic groove. We adopted an intermediate approach via the triangular method. An ultrasound knife was used to open the mesenteric bridge, and dissection was completed toward the cephalic side up to the root of the inferior mesenteric vessels. At this point, a bright “Toldt’s space” was observed under high tension. Next, we continued to operate around the root of inferior mesenteric vessels to dissect the 253 group LNs, which was guided by the fluorescence. When the LN dissection was finished, we used the fluorescence again to ensure no LNs remained (Figure 1).

Figure 1 Fluorescence-guided LN dissection. (A) The 253 group LNs under fluorescence. (B) Intermediate approach to locating the mesenteric bridge. (C) Exposure of the root of the inferior mesenteric artery and IMP. (D) Residual LN under fluorescence. IMP, inferior mesenteric plexus; LN, lymph node.

We continued the dissection along the inferior mesenteric artery and revealed its main branches. In this patient, the superior rectal artery shared a common trunk with the sigmoid artery. We reserved the left colonic artery via lower ligation. Next, we ligated the inferior mesenteric vein at the root site. We further opened Toldt’s space toward the lateral side until the line of Told, pretrial fascia, and the dorsal part of mesocolon were visible. We then dissected the fusion fascia and linked it to the lateral plane. Toldt’s space was further expanded toward the cephalic side until the whole pretrial fascia was visible (Figure 2).

Figure 2 Ligation of the inferior mesenteric artery and clipping of the mesosigmoid. (A) Ligation of the inferior mesenteric artery and vein. (B,C) Extension of Toldt’s space and connection with the lateral space. (D-F) Ligation of the branches of the sigmoid artery under fluorescence. IMA, inferior mensenteric artery; IMV, inferiro mesenteric vein.

ICG (2.5 mg/mL) was administered via intravenous injection to reveal the vascular contour under fluorescence imaging. The first branch of the sigmoid artery was first identified, and we dissected the mesosigmoid along its internal side. The first branch of the sigmoid vein was also ligated at the site inferior to the root of the first branch of the sigmoid artery (Figure 2).

Subsequently, we began to operate in the pelvic space. We first dissected the loose tissue in the retrorectal space, extending toward the caudal side until the rectosacral fascia was revealed. We entered into the superior levator anal space following the dissection of the rectosacral fascia. In this procedure, care should be taken to ensure the integrity of the anterior sacral fascia and to avoid injury to the presacral venous plexus (Figure 3).

Figure 3 Dissociation of the mesorectum. (A,B) Operation in the retrorectal space. (C-E) Dissociation of the anterior rectal space. (F-H) Extension into the lateral space. DF, Denonvilliers’ fascia; NVB, neurovascular bundle; PSVP, presacral venous plexus.

We then revealed the lateral rectal space at the level of the mid-rectum with the assistance of triangle traction. We opened the peritoneum at a site 1 cm above the peritoneal reflection and entered into the anterior space of Denonvilliers’ fascia. When the anterior and posterior rectal space was adequately revealed, we further extended the lateral rectal space with the help of high tension. In this procedure, particular attention is needed to avoid injury to the neurovascular bundle (NVB) (Figure 3).

When the lateral rectal space was adequately extended, we transversely dissected the anterior lobe of Denonvilliers’ fascia at 0.5 cm above the inferior edge of the seminal vesicle. As a result, we entered into the posterior lobe of Denonvilliers’ fascia (Figure 3).

We then turned to the posterior rectal space, dissecting along the surface of the levator ani muscle to the level of the hiatal ligament. We further extended the right lateral space with high tension. The pelvic plexus should be carefully protected during this procedure. When the dissection came to the level of hiatus of the levator ani muscle, we turned to the left space and continued the dissection along the surface of the levator ani muscle. When the dissection reached the distal margin of the mesorectum, we opened the left hiatus of the levator ani muscle and entered into the left sphincter space. In this procedure, care should be taken to avoid injury to the sphincter.

We turned over and further extended the posterior space of Denonvilliers’ fascia. Similarly, we continued to reveal the right distal margin of the mesorectum, opened the right hiatus of the levator ani muscle, and entered into the right sphincter space. We then turned into the posterior rectal space again. The hiatal ligament became visible when the sphincter muscle was adequately revealed. We used an ultrasound knife to ligate the posterior portion of the hiatal ligament and further extended the intersphincteric space (Figure 4).

Figure 4 Exposure of the intersphincteric space. (A) Left intersphincteric space. (B) Right intersphincteric space. (C) Hiatal ligament. (D) Posterior view of the intersphincteric space.

The surgeon completed digital examination to mark the lower edge of the rectal tumor and the distal resection margin. After transanal lavage, the rectum was transversely resected with a line stapler.

We made a small incision in the hypogastrium and removed the tumor. After dissecting the mesocolon and labeling the proximal resection margin, we injected 3-mL of ICG venously to assess the blood supply to the proximal colon. Subsequently, we removed the specimen and placed the head of the circular stapler to the proximal colon.

We re-established the pneumoperitoneum and washed the pelvic cavity with normal saline. Under fluorescence, we could see that the 253 LNs were completely dissected. The inferior mesenteric plexus, hypogastric nerve, and superior hypogastric plexus were perfectly preserved. We placed the rod part of the circular stapler through the anus and finished the anastomosis. We again checked the blood supply to the anastomosis via fluorescence and conducted an aeration test. Subsequently, double catheterization to the pelvic cavity was completed, and the floor of the peritoneum was closed. Finally, we reinforced the anastomosis through the anus via disc pull hook and completed prophylactic ileostomy (Figure 5).

Figure 5 Tumor removal and primary anastomosis. (A,B) Overview of the nervous structure after tumor removal. (C) Overview of the intersphincteric space. (D) Incision line of the proximal colon under fluorescence. (E) The blood supply to the anastomosis under fluorescence. (F) Reinforcement of the anastomosis through the anus. IHP, inferior hypogastric plexus; IMP, inferior mesenteric plexus.

Postoperative considerations and tasks

The duration of this operation was 215 minutes, and the estimated blood loss was 20 mL. The patient was placed on a fluid diet 2 days after surgery and was discharged 7 days after surgery. No postoperative complications were observed. The pathological stage was T2N0M0, and gene testing indicated that the tumor had microsatellite stability; thus, adjuvant therapy was omitted. The patient attended the outpatient center for a follow-up visit 6 months after surgery: no tumor recurrence was found, and the patient indicated that he had genitourinary function comparable to that experienced pretreatment.

Tips and pearls

In this procedure, the fluorescence technique was used for the LN dissection and the check for blood supplement to anastomosis site. The concentration of ICG and the time to fluorescence mode were the key steps in this procedure.

It should be administered intravenously at least 5–10 minutes prior to LN dissection to ensure sufficient time for uptake and accurate lymphatic mapping. For anastomotic perfusion assessment, ICG is administered after rectal transection but before stapling to evaluate stump vascularity in real time.

A well-perfused anastomosis shows rapid, homogeneous fluorescence; patchy or delayed uptake suggests ischemia and may require resection revision. Excessive tension or overuse of energy devices near the anastomotic site should be avoided to preserve microcirculation.

Discussion

Surgical highlights

We conducted fluorescence-guided laparoscopic-assisted transabdominal ISR for ultralow rectal cancer. All aspects of the procedure were completed smoothly, and the anatomical structure was clearly indicated.

With the development of minimally invasive techniques for rectal cancer resection, membrane anatomy and function preservation have been increasingly emphasized in recent years (9). As shown in Video 1, we maintained the operation in the correct surgical plane and aimed to preserve the completeness of membrane structures throughout the entire procedure. We believe that this can reduce incident bleeding and the operation time. To achieve these results, the surgeon must have a deep understanding of anatomy and mature operating skills. When compared with transanal ISR, transabdominal ISR is more demanding, as the surgeon must operate in the deepest site of the pelvic floor (10). In our case, we first performed sufficient isolation in the posterior space of the rectum, followed by extension of the bilateral space. As indicated by Wang et al., this step can help better protect the NVB and ensure completeness of the mesorectum (11). Additionally, we first revealed the whole trunk of the pelvic plexus to enhance protection. We believe these particular measures can improve function outcomes. When operating on the pelvic floor, we entered into the intersphincteric space and rendered the fissure ligament visible. This could help achieve a safer resection margin when ISR was performed via the transabdominal method.

Another feature of this procedure is the application of fluorescence. After the ligation of the inferior mesenteric artery and the primary dissection of the 253 group LNs, we used fluorescence imaging for examination. We found several small remaining LNs and continued LN dissection until no LNs were visible under fluorescence. Research suggests that fluorescence imaging can help improve the harvesting of LNs in CRC surgery (12). Although the positive rate of the 253 group LN is fairly low in rectal cancer, it is associated with poor prognosis. A study has even indicated that 253 group LN metastasis is a better predictor of poorer survival than is lateral LN metastasis (13). The dissection boundary of the 253 group LN remains controversial. Controlling the injection time and site is critical to the successful application of the fluorescence technique. It has been recommended that ICG be injected into the submucosal layer around tumor about 1 day before surgery (14), and we recommend this procedure be completed by experienced endoscopists.

Strengths and limitations

AL is the most dangerous complication following rectal cancer resection with primary anastomosis. The incidence of AL ranges from 5–10% and is even higher in cases of ultralow anastomosis (15). AL can reduce a patient’s quality of life and shorten survival time. Several factors can contribute to AL, with a poor blood supply being the most prominent. Thus, surgeons should be particularly careful during the operation to preserve as many vessels as possible to ensure optimal blood supply to the anastomosis. However, in the past, the techniques available for the real-time monitoring of the blood supply to the anastomosis have been insufficient. Under the fluorescence model, the intraoperative injection of ICG can clearly visualize the vessels providing blood flow to the anastomosis—an advantage featured in Video 1. If surgeons are unsatisfied with the blood supply, anastomosis may be repeated. Overall, research suggests that fluorescence can help reduce the risk of postoperative AL. The main limitation of this study is that it is a single case report. Conclusions drawn from one successful outcome cannot be generalized to all patients with ultralow rectal cancer, as the positive result could be due to patient-specific factors rather than the technique itself. Furthermore, the 6-month follow-up period is too short to assess long-term oncological outcomes like 5-year survival or local recurrence rates, which are the ultimate measures of a cancer surgery’s success. Finally, there is a potential for reporting bias, as studies detailing successful applications of a new technique are more likely to be published than those with negative outcomes.

Conclusions

The application of fluorescence-guided assistance in laparoscopic ISR represents a significant advancement in surgical precision and patient outcomes. This technique enhances LN dissection by improving intraoperative visualization, thereby increasing the likelihood of complete oncological clearance. Additionally, the real-time assessment of anastomotic perfusion reduces the risk of postoperative complications, such as anastomotic leakage, by ensuring optimal blood supply to the rectal stump.

Our findings suggest that fluorescence-assisted laparoscopy not only refines the technical execution of ISR but also contributes to safer and more effective surgical outcomes. Further large-scale, prospective studies are warranted to validate its long-term benefits and broader applicability in colorectal surgery.

This innovation holds promise for standardization in minimally invasive rectal cancer surgery, combining oncological rigor with enhanced functional preservation. However, the effect of fluorescence technique still should be further investigated by prospective studies and long-term follow-up.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the SUPER reporting checklist. Available at https://jgo.amegroups.com/article/view/10.21037/jgo-2025-642/rc

Peer Review File: Available at https://jgo.amegroups.com/article/view/10.21037/jgo-2025-642/prf

Funding: This study was supported by Natural Science Foundation of Anhui Province (No. 2308085MH274), the Research Start-up Fund of The First Affiliated Hospital of USTC, University of Science and Technology of China (No. RC2021014), and Outstanding Young and Middle-aged Talent Fund of The First Affiliated Hospital of USTC, University of Science and Technology of China (No. QJ202310).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jgo.amegroups.com/article/view/10.21037/jgo-2025-642/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for publication of this manuscript, the accompanying image, and the video. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Siegel RL, Wagle NS, Cercek A, et al. Colorectal cancer statistics, 2023. CA Cancer J Clin 2023;73:233-54. [Crossref] [PubMed]
2. DiBrito SR, Manisundaram N, Kim Y, et al. Perioperative and oncological outcomes following robotic en bloc multivisceral resection for colorectal cancer. Colorectal Dis 2024;26:949-57. [Crossref] [PubMed]
3. Ito M, Tsukada Y, Watanabe J, et al. Long-term survival and functional outcomes of laparoscopic surgery for clinical stage I ultra-low rectal cancers located within 5 cm of the anal verge: A prospective phase II trial (Ultimate trial). Ann Surg 2024;281:304-11. [Crossref] [PubMed]
4. Sun L, Zhou J, Ji L, et al. Sphincter-preserving effect of robotic-assisted intersphincteric resection for ultra-low rectal cancer: a propensity score matching analysis. J Robot Surg 2024;18:83. [Crossref] [PubMed]
5. Guo Y, He L, Tong W, et al. Intersphincteric resection following robotic-assisted versus laparoscopy-assisted total mesorectal excision for middle and low rectal cancer: a multicentre propensity score analysis of 1571 patients. Int J Surg 2024;110:1904-12. [Crossref] [PubMed]
6. Zhang C, Tan H, Xu H, et al. The role of robotic-assisted surgery in the management of rectal cancer: a systematic review and meta-analysis. Int J Surg 2024;110:6282-96. [Crossref] [PubMed]
7. Tang B, Zhou S, He K, et al. Applications of Near-Infrared Fluorescence Imaging and Angiography of Inferior Vesical Artery in Laparoscopic Lateral Lymph Node Dissection: A Prospective Nonrandomized Controlled Study. Dis Colon Rectum 2024;67:175-84. [Crossref] [PubMed]
8. Lucarini A, Guida AM, Orville M, et al. Indocyanine green fluorescence angiography could reduce the risk of anastomotic leakage in rectal cancer surgery: a systematic review and meta-analysis of randomized controlled trials. Colorectal Dis 2024;26:408-16. [Crossref] [PubMed]
9. Wang J, Liu H, Li A, et al. A new membrane anatomy-oriented classification of radical surgery for rectal cancer. Gastroenterol Rep (Oxf) 2023;11:goad069. [Crossref] [PubMed]
10. Li S, Pan Z, Wang Y, et al. Transabdominal minimal invasive surgery for ultralow anterior resection-intersphincteric dissection with total hiatal ligament excision and rectal pull-through and eversion for direct access to the distal resection margin - a video vignette. Colorectal Dis 2024;26:1465-6. [Crossref] [PubMed]
11. Wang X, Jiang W, Deng Y, et al. Unraveling variations and enhancing prediction of successful sphincter-preserving resection for low rectal cancer: a post hoc analysis of the multicentre LASRE randomized clinical trial. Int J Surg 2024;110:4031-42. [Crossref] [PubMed]
12. Hamabe A, Ogino T, Tanida T, et al. Indocyanine green fluorescence-guided laparoscopic surgery, with omental appendices as fluorescent markers for colorectal cancer resection: a pilot study. Surg Endosc 2019;33:669-78. [Crossref] [PubMed]
13. Inoue H, Sasaki K, Nozawa H, et al. Therapeutic significance of D3 dissection for low rectal cancer: a comparison of dissections between the lateral pelvic lymph nodes and the lymph nodes along the root of the inferior mesenteric artery in a multicenter retrospective cohort study. Int J Colorectal Dis 2021;36:1263-70. [Crossref] [PubMed]
14. Hagiwara C, Wakabayashi T, Tsutsui A, et al. Time required for indocyanine green fluorescence emission for evaluating bowel perfusion in left-sided colon and rectal cancer surgery. Surg Endosc 2023;37:7876-83. [Crossref] [PubMed]
15. Rutegård M, Jutesten H, Buchwald P, et al. Minor impact of anastomotic leakage in anterior resection for rectal cancer on long-term male urinary and sexual function. Int J Colorectal Dis 2024;39:49. [Crossref] [PubMed]

(English Language Editor: J. Gray)