Autonomic Nerve-Preserving Lymph Node Dissection for Lateral Pelvic Lymph Node Metastasis of the Pelvic Floor Using the Transanal Approach

Reversed anatomy in transanal lateral lymph node dissection: landmarks and pitfalls

Lateral lymph node dissection (LLND) is getting global attention as an a surgical option to reduce local recurrence in locally advanced rectal cancer. As the transanal total mesorectal excision (TaTME) is gaining popularity worldwide, a novel LLND approach was established adopting a two-team approach that combines the transabdominal and transanal approaches using the TaTME technique. This narrative review describes the advantages, anatomical landmarks, surgical techniques, and pitfalls of transanal LLND (TaLLND). The advantages of TaLLND include a magnified view and enhanced maneuverability of the laparoscopic instruments in the deep pelvis. TaLLND is also beneficial for LLND in patients with a history of pelvic surgery because surgeons can have access to the areas unaffected by previous surgery. To master the TaLLND technique, the procedure should be understood according to the following steps: S4 nerve identification, lateral space entry, lateral dissection, obturator vein, artery, and nerve identification, dissection along the external iliac vein, medial dissection, median and bottom dissection, dissection along the internal iliac artery, and dissection along the obturator nerve. TaLLND can be applied to highly advanced disease that requires combined resection of the major internal iliac vessels, pelvic nerves, or adjacent organs. In such cases, simultaneous transanal and transabdomiinal LLND utilizing a two team approach has advantages as these approaches can provide mutual complementary roles. TaLLND is expected to overcome the difficulty of transabdominal LLND and improve the quality of LLND.

Role of Lateral Pelvic Node Dissection in Rectal Cancer Surgery

The role of lateral pelvic lymph node dissection in the treatment of patients with locally advanced rectal cancer is a matter of controversy. Surgical practices in Korea and Japan have accepted this approach and are widely utilized; however, it is not routinely incorporated in the practice of countries in the Western hemisphere. This review will examine the role of lateral pelvic lymph node dissection.

Transanal Minimally Invasive Surgical Approach to Total Pelvic Exenteration

BACKGROUND

Total pelvic exenteration, a surgical procedure for patients with highly advanced primary and recurrent rectal cancer, is technically demanding.

IMPACT OF INNOVATION

We report the utility of a transanal minimally invasive surgical approach to total pelvic exenteration.

TECHNOLOGY MATERIALS AND METHODS

A 2-team approach with a laparoscopic transabdominal approach and transanal minimally invasive surgery was adopted. During the transabdominal approach in the pelvis, dissection was performed to remove the pelvic organs and visceral branches of the internal iliac vessels. The dissection goal via the transabdominal approach is the levator ani. During the transperineal approach, dissection is performed along the levator ani, and the tendinous arch of the levator ani is penetrated at the lateral side to achieve rendezvous between the 2 approaches. The levator ani is then dissected circumferentially, with identification of the internal pudendal vessels passing through the levator ani at the 4 o'clock and 8 o'clock positions, known as Alcock's canal. The anterior wall of Alcock's canal is formed by the coccygeus muscle and sacrospinous ligament, which are dissected by the transperineal approach to open Alcock's canal, thus obtaining a clear view of the internal pudendal vessels. On the anterior side, the urethra is divided with a laparoscopic linear stapler via the transperineal approach.

PRELIMINARY RESULTS

Eight patients with rectal cancer underwent this procedure. The median (range) blood loss was 200 (120-1520) mL and operating time was 467 (321-833) minutes. Reoperation was performed in 1 internal hernia case; however, there were no mortalities, and there were no cases with severe complications or conversion to open surgery.

CONCLUSIONS AND FUTURE DIRECTIONS

When performing total pelvic exenteration, transanal minimally invasive surgery offers direct visualization behind the tumor from the anal side and shows the deep pelvic structures, including the retroperitoneal space of the pelvic sidewall.

Long-term outcomes of indocyanine green fluorescence imaging-guided laparoscopic lateral pelvic lymph node dissection for clinical stage II/III middle-lower rectal cancer: a propensity score-matched cohort study

BACKGROUND

We previously reported that indocyanine green fluorescence imaging (ICG-FI)-guided laparoscopic lateral pelvic lymph node dissection (LPLND) was able to increase the total number of harvested lateral pelvic lymph nodes without impairing functional preservation. However, the long-term outcomes of ICG-FI-guided laparoscopic LPLND have not been evaluated. The aim of the present study was to compare the long-term outcomes of ICG-FI-guided laparoscopic LPLND to conventional laparoscopic LPLND without ICG-FI.

METHODS

This was a retrospective, multi-institutional study with propensity score matching. The study population included consecutive patients with middle-low rectal cancer (clinical stage II to III) who underwent laparoscopic LPLND between January 2013 and February 2018. The main evaluation items in this study were the 3-year overall survival, relapse-free survival (RFS), local recurrence rate, and lateral local recurrence (LLR) rate.

RESULTS

A total of 172 patients with middle-lower rectal cancer who had undergone laparoscopic LPLND were included in this study. After propensity score matching, 58 patients were matched in each of the ICG-FI and non-ICG-FI groups. There were no substantial differences in the baseline characteristics between the two groups. The ICG-FI group and non-ICG-FI group included 40 and 38 women and had a median age of 65 (IQR 60-72) and 66 (IQR 60-73) years, respectively. The median follow-up for all patients was 63.7 (IQR 51.3-76.8) months. The estimated respective 3-year overall survival, RFS, and local recurrence rates were 93.1%, 70.7%, and 5.2% in the ICG-FI group and 85.9%, 71.7%, and 12.8% in the non-ICG-FI group (p = 0.201, 0.653, 0.391). The 3-year cumulative LLR rate was 0% in the ICG-FI group and 9.3% in the non-ICG-FI group (p = 0.048).

CONCLUSIONS

This study revealed that laparoscopic LPLND combined with ICG-FI was able to decrease the LLR rate. It appears that ICG-FI could contribute to improving the quality of laparoscopic LPLND and strengthening local control of the lateral pelvis.

TRIALS REGISTRATION

This study was registered with the Japanese Clinical Trials Registry as UMIN000041372 ( http://www.umin.ac.jp/ctr/index.htm ).

Initial experience with the transanal approach for lateral pelvic lymph node dissection in rectal cancer

BACKGROUND

The efficacy and safety of transanal lateral pelvic lymph node dissection (TaLPLND) in rectal cancer has not yet been clarified. The aim of the present study was to evaluate the short-term results as an initial experience of TaLPLND.

METHODS

This retrospective study included patients with middle to lower rectal cancer who underwent TaLPLND from July 2018 to July 2021. Our institutions targeted lymph nodes in the internal iliac area and the obturator area for lateral pelvic lymph node dissection (LPLND).

RESULTS

A total of 30 consecutive patients with rectal cancer were included in this analysis. The median age was 60 years (range, 36-83 years), and the male-female ratio was 2:1. The median operative time was 362 min (IQR, 283-661 min), and the median intraoperative blood loss was 74 ml (IQR, 5-500 ml). Intraoperative blood transfusion was required in one case. No cases required conversion to laparotomy. TaLPLND was performed bilaterally in 13 patients (43.3%). Five patients (16.7%) underwent LPLND with combined resection of the internal iliac vessels. The median distance of the distal margin from the anal verge was 20 mm. The pathological radial margin (pRM) was positive in one case, and the negative pRM rate was 96.7%. Short-term postoperative complications (Clavien-Dindo classification grade ≥ II) were observed in nine cases (30.0%). There were no cases of reoperation or mortality. The median number of harvested lateral pelvic lymph nodes was 11 (range, 3-28). On pathological examination, lateral pelvic lymph nodes were positive for metastasis in seven cases (23.3%).

CONCLUSIONS

TaLPLND appeared to be beneficial from an oncological point of view because it was close to the upstream lymphatic drainage from the tumor. The short-term outcomes of this initial experience indicate that this novel approach is feasible.

Transanal lateral lymph node dissection with intraoperative hologram support in low rectal cancer

BACKGROUND

In Japan, the standard treatment for stage II/III advanced low rectal cancer is total mesorectal excision plus lateral lymph node dissection (LLND). There are also recent reports on the use of transanal LLND. However, the transanal anatomy is difficult to understand, and additional support tools are required to improve the surgical safety. The present study examined the utility of holograms with mixed reality as an intraoperative support tool for assessing the complex pelvic anatomy.

METHODS

Polygon (stereolithography) files of patients' pelvic organs were created and exported from the SYNAPSE VINCENT imaging system and uploaded into the Holoeyes MD virtual reality software. Three-dimensional images were automatically converted into patient-specific holograms. Each hologram was then installed into a head mount display (HoloLens2), and the surgeons and assistants wore the HoloLens2 when they performed transanal LLND. Twelve digestive surgeons with prior practice in hologram manipulation evaluated the utility of the intraoperative hologram support by means of a questionnaire.

RESULTS

Intraoperative hologram support improved the surgical understanding of the lateral lymph node region anatomy. In the questionnaire, 75% of the surgeons answered that the hologram accurately reflected the anatomy, and 92% of the surgeons answered that the anatomy was better understood by simulating the hologram intraoperatively than preoperatively. Moreover, 92% of the surgeons agreed that intraoperative holograms were a useful support tool for improving the surgical safety.

CONCLUSIONS

Intraoperative hologram support improved the surgical understanding of the pelvic anatomy for transanal LLND. Intraoperative holograms may represent a next-generation surgical tool for transanal LLND.

Two-team lateral lymph node dissection assisted by the transanal approach for locally advanced lower rectal cancer: comparison with the conventional transabdominal approach

BACKGROUND

An optimal surgical approach to lateral lymph node dissection (LLND) remains controversial. With the recent popularity of transanal total mesorectal excision, a two-team procedure combining the transabdominal and transanal approaches was established as a novel approach to LLND. This study aimed to clarify the safety and feasibility of two-team LLND (2team-LLND) and compare its short-term outcomes with those of conventional transabdominal LLND (Conv-LLND).

METHODS

Between April 2013 and March 2020, 463 patients diagnosed with primary locally advanced rectal cancer underwent a transanal total mesorectal excision; among them, 93 patients who underwent bilateral prophylactic LLND were included in this single-center, retrospective study. Among these patients, 50 and 43 patients underwent Conv-LLND (the Conv-LLND group) and 2team-LLND (the 2team-LLND group), respectively. The short-term outcomes, including the operation time, blood loss volume, number of complications, and number of harvested lymph nodes, were compared between the two groups.

RESULTS

The intraoperative and postoperative complications in the 2team-LLND group were equivalent to those in the Conv-LLND group; furthermore, the incidence of postoperative urinary retention in the 2team-LLND group was acceptably low (9%). Compared with the Conv-LLND group, the 2team-LLND group had a significantly shorter operation time (P = 0.003), lower median blood loss (P = 0.02), and higher number of harvested lateral lymph nodes (P = 0.0005).

CONCLUSION

The intraoperative and postoperative complications of 2team-LLND were comparable with those of Conv-LLND. Thus, 2team-LLND was safe and feasible for advanced lower rectal cancer. Moreover, it was superior to Conv-LLND in terms of the operation time, blood loss volume, and number of harvested lateral lymph nodes. Therefore, it can be a promising LLND approach.

Current status of transanal total mesorectal excision for rectal cancer and the expanding indications of the transanal approach for extended pelvic surgeries

Transanal total mesorectal excision (taTME) has been rapidly accepted as a promising surgical approach to the distal rectum. The benefits include ease of access to the bottom of the deep pelvis linearly over a short distance in order to easily visualize the important anatomy. Furthermore, the distal resection margins can be secured under direct vision. Additionally, a two-team approach combining taTME with a transabdominal approach could decrease the operative time and conversion rate. Although taTME was expected to become more rapidly popularized worldwide, enthusiasm for it has stalled due to unfamiliar intraoperative complications, a lack of oncologic evidence from randomized trials, and the widespread use of robotic surgery. While international registries have reported favorable short- and medium-term outcomes from taTME, a Norwegian national study reported a high local recurrence rate of 9.5%. The characteristics of the recurrences included rapid, multifocal growth in the pelvis, which was quite different from recurrences following traditional transabdominal TME; thus, the Norwegian Colorectal Cancer Group reached a consensus for a temporary moratorium on the performance of taTME. To ensure acceptable baseline quality and patient safety, taTME should be performed by well-trained colorectal surgeons. Although the appropriate indications for taTME remain controversial, the transanal approach is extremely important as a means of goal setting in difficult TME cases and as an aid to the transabdominal approach in various types of extended pelvic surgeries. The benefits in transanal lateral lymph node dissection and pelvic exenteration are presented herein.

Laparoscopic Extraperitoneal Approach to Bilateral Pelvic Lymph Node Dissection in Low Rectal Cancer: Technique with Video and 3D Modeling

BACKGROUND

Lateral pelvic lymph node dissection for rectal cancer is a difficult technique due to the complex pelvic anatomy. Recent series have underlined the importance of lateral lymphadenectomy in selective patients to prevent local recurrence of rectal cancer.

METHODS

A 65-year-old woman was diagnosed with locally advanced rectal adenocarcinoma of the low rectum with right and left lateral pelvic lymph nodes of respectively 9 and 13 mm. After chemotherapy followed by radiotherapy, the size of the right internal iliac lymph nodes remained enlarged to 5 mm. A laparoscopic extraperitoneal approach was used for total mesorectal excision, complete mesocolic excision, and bilateral lateral lymph node dissection. The extraperitoneal space was divided into the subperitoneal space dissected by a transanal approach and the retroperitoneal space dissected by a transabdominal approach.

RESULTS

The operating time was 303 min, and the estimated blood loss was 270 ml. No intraoperative adverse events occurred. Bilateral lymph node dissection was performed with obturator nerve and neurovascular bundle sparing. A postoperative complication classified as Clavien 3a arose with a pelvic infection but no anastomotic leakage. Final pathology disclosed T3N1M0 adenocarcinoma with free surgical margins. The patient never had urinary dysfunction.

CONCLUSIONS

The laparoscopic extraperitoneal approach to lateral pelvic lymph node dissection is feasible. For lateral lymph node dissection, the transanal approach may have some advantages over the standard transabdominal approach, with better visibility of and access to the distal internal iliac area. This video may help oncological surgeons to perform this new and complex 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.

Particle Swarm Algorithm-Based Analysis of Pelvic Dynamic MRI Images in Female Stress Urinary Incontinence

This work aimed to study the application of pelvic floor dynamic images of magnetic resonance imaging (MRI) based on the particle swarm optimization (PSO) algorithm in female stress urinary incontinence (SUI). 20 SUI female patients were selected as experimental group, and another 20 healthy females were taken as controls. PSO algorithm, K-nearest neighbor (KNN) algorithm, and back propagation neural network (BPNN) algorithm were adopted to construct the evaluation models for comparative analysis, which were then applied to 40 cases of female pelvic floor dynamic MRI images. It was found that the model proposed had relatively high prediction accuracy in both the training set (87.67%) and the test set (88.46%). In contrast to the control group, there were considerable differences in abnormal urethral displacement, urethral length changes, bladder prolapse, and uterine prolapse in experimental patients (P < 0.05). After surgery, the change of urethral inclination angle was evidently reduced (P < 0.05). To sum up, MRI images can be adopted to assess the occurrence of female SUI with abnormal urethral displacement, shortening of urethra length, bladder prolapse, and uterine prolapse. After surgery, the abnormal urethral movement was slightly improved, but there was no obvious impact on bladder prolapse and uterine prolapse.

Lateral pelvic lymph node dissection in the management of locally advanced low rectal cancer: Summary of the current evidence

Lateral pelvic lymph nodes (LPLN) are a major site for local recurrence following curative resection for low locally advanced rectal cancer. Ongoing advances in imaging techniques have improved predicting LPLN metastasis (LPLNM) during pre-operative staging. However, there is ongoing debate on optimal management of this subgroup of patients with variation between guidance of different societies. In Japan, LPLNM is considered as local disease and addressed by lateral pelvic node dissection (LPLND) in addition to total mesorectal excision (TME). However, in the west, LPLNM is considered as metastatic disease and those patients are offered neoadjuvant chemoradiotherapy (nCRT) followed by TME surgery. The potential surgical risks and morbidity associated with LPLND as well as the uncertainty of the oncological outcome have raised the concern that patients with locally advanced low rectal cancer with LPLNM could be over or under-treated. A comprehensive review of literature was performed, summarizing the current evidence on available modalities for predicting LPLNM, the role of LPLND in the management of advanced low rectal cancer and the available surgical approaches with their impact on surgical and oncological outcomes. LPLND is associated with increased operative time, blood loss and post-operative morbidity. The potential benefits for local disease control and survival still awaits high quality studies. There has been increasing number of reports of the use minimally invasive approaches in LPLND in an attempt to reduce post-operative complications. There is need for high quality evidence to define the role of LPLND in management of patients with advanced low rectal cancer.

Short- and long-term outcomes of laparoscopic versus open lateral lymph node dissection for locally advanced middle/lower rectal cancer using a propensity score-matched analysis

BACKGROUND

There are few reports on large-scale trials for the long-term outcomes regarding laparoscopic lateral lymph node dissection (LLND). We evaluated the short- and long-term outcomes of laparoscopic versus open LLND for locally advanced middle/lower rectal cancer using a propensity score-matched analysis.

METHODS

From January 2005 to December 2016, consecutive clinical stage II to III middle/lower rectal cancer patients who underwent total mesorectal excision (TME) plus LLND were retrospectively collected at three institutions. Laparoscopic LLND was compared with open LLND for the surgical and oncological outcomes, including the long-term survival, using a propensity score-matched analysis.

RESULTS

A total of 325 patients were collected. There were 142 patients who underwent open TME plus LLND (open group) and 183 patients who underwent laparoscopic TME plus LLND (laparoscopic group). A total of 93 patients each were matched to each group. Compared to the open group, the laparoscopic group had a significantly longer operative time (327 vs. 377 min; p = 0.002) but significantly less blood loss (540 vs. 50 ml; p < 0.001), fewer Clavian-Dindo grade ≥ 2 postoperative complications (49.5% vs. 34.4%; p = 0.037) and shorter postoperative hospital stay (18 vs. 14 days; p = 0.008). Furthermore, the rate of urinary retention was significantly lower in the laparoscopic group than in the open group (16.1% vs. 6.5%; p = 0.037). The estimated 3-year overall survival, relapse-free survival, and cumulative incidence of local recurrence were 91.4%, 73.1%, and 3.4% in the open group and 90.3%, 74.2%, and 4.3% in the laparoscopic group (p = 0.879, 0.893, 0.999), respectively.

CONCLUSIONS

This study showed that laparoscopic LLND had advantages over an open approach, such as less blood loss, fewer postoperative complications, and a shorter postoperative hospital stay, and the oncologic outcomes were similar to the open approach. Laparoscopic LLND could be a viable standard approach to LLND for advanced middle/lower rectal cancer surgery.

Does adding lateral pelvic lymph node dissection to neoadjuvant chemotherapy improve outcomes in low rectal cancer?

PURPOSE

Lateral pelvic lymph node metastasis occurs in 15 to 20% of patients with locally advanced low rectal cancer which increases risk of local recurrence and reduced survival following neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME). Adding lateral pelvic lymph node dissection (LPLND) could improve outcomes in those patients. This review aims to determine if the addition of LPLND to the conventional management of advanced rectal cancer would yield improved outcomes.

METHODS

OVID Medline, Cochrane, Clinicaltrials.gov , EMBASE, Clinicaltrialsregister.eu, Web of Knowledge and CABAbstracts were searched using the following keywords: 'lateral pelvic lymph node dissection', 'pelvis lymphadenectomy', 'chemoradi*', 'rectal cancer', 'rectal neoplasm', 'rectal carcinoma' and 'rectal tumour'. Studies were included if they were in English and included rectal cancer patients that had nCRT, rectal resection ± LPLND. Primary outcome was 3-year and 5-year local recurrence. Secondary outcome was 3-year and 5-year overall survival.

RESULTS

Six studies were identified with 1210 patients who had nCRT and TME, and 268 patients who had nCRT and rectal resection plus LPLND. Patients who had LPLND had non-significant lower 3-year and 5-year local recurrence rate compared with those who did not (p = 0.10 and p = 0.12, respectively). They demonstrated a lower 3-year overall survival but higher 5-year overall survival and both were not significant (p = 0.81 and p = 0.57, respectively).

CONCLUSION

Available evidence suggests that there is no significant reduction in local recurrence rates or improved survival from LPLND to the current treatment modalities. Further studies are required to define the role of lateral pelvic lymph node dissection in low rectal cancer.