Laparoscopic en bloc resection of obturator lymph node: a surgical education video

Introduction

Background

Pelvic lymph node enlargement may be attributed to various causes such as infection, inflammatory changes, immune-related factors, or medication. However, when the short-axis diameter of pelvic or retroperitoneal lymph nodes reaches ≥10 mm (1), it is commonly considered suspicious for metastasis from pelvic malignancies, including cervical cancer (2), endometrial cancer (3), bladder cancer (4), and urethral cancer (5).

Rationale and knowledge gap

Cervical intraepithelial neoplasia grade III (CIN III) is characterized by severe dysplastic changes of epithelial cells at the transformation zone of the cervix, where the columnar endocervical epithelium meets the squamous ectocervical epithelium (6). Although CIN III is generally regarded as a precancerous lesion of the cervix, lymph node metastasis has not been reported to date in those cases. Treatment strategies for CIN III are individualized based on factors such as the patient’s human papillomavirus (HPV) status, age, and fertility desires, ranging from cervical conization to total hysterectomy. Preoperative imaging typically including transvaginal ultrasound, pelvic computed tomography (CT) and magnetic resonance imaging (MRI).

Ultrasound is a convenient and cost-effective first-line modality for evaluating superficial lymph nodes. However, its effectiveness for assessing deep pelvic lymph nodes is limited. Moreover, ultrasound is highly dependent on the operator’s expertise (6). Consequently, occult lymph node metastases from other malignancies may remain undetected preoperatively and are only discovered intraoperatively. Surgical management of such incidentally enlarged lymph nodes demands exceptional clinical judgment and technical proficiency in achieving complete nodal dissection.

Objective

This surgical video (Video 1) is based on a case of an unexpected enlarged obturator lymph node detected during laparoscopic hysterectomy for CIN III, which has been finally confirmed as the metastasis from urethral moderately differentiated squamous cell carcinoma (USCC). The 64-year-old postmenopausal woman with no remarkable past medical history was referred to our department following abnormal cervical cancer screening results. The patient tested positive for HPV-16, and colposcopy-guided cervical biopsy confirmed the presence of CIN III. After comprehensive evaluation, the surgical plan for this patient was determined as follows: initial cervical conization would be performed, and if intraoperative frozen section analysis revealed no more severe pathology, laparoscopic total hysterectomy with bilateral salpingo-oophorectomy would be subsequently carried out. During the procedure, a 5-cm enlarged right obturator lymph node was unexpectedly discovered in a high-risk anatomical location: adherent to the external iliac vein and encircled by the obturator nerve. Given concern for malignancy, an en bloc resection was performed to avoid tumor fragmentation and potential dissemination. This video article demonstrates the technical approach to resecting such high-risk nodal metastases, aiming to enhance surgical education for managing intraoperatively detected lymphatic spread. We present this article in accordance with the SUPER reporting checklist (available at https://gpm.amegroups.com/article/view/10.21037/gpm-25-25/rc).

Preoperative preparations and requirements

Patient preparation

• Anesthetic evaluation confirmed surgical eligibility 24 hours prior.
• Mechanical bowel preparation included oral laxatives (evening before) and cleansing enemas (evening and morning of surgery).
• Vaginal disinfection with 1% povidone-iodine was performed twice: preoperatively at night and repeated on the morning of surgery.
• Vulvar/umbilical skin preparation was completed one day prior.
• On the operative day, the patient was positioned in lithotomy with protective padding. Intravenous antibiotic prophylaxis was administered 30 minutes before incision. General anesthesia was induced, followed by urinary catheterization and uterine manipulator placement. Pneumoperitoneum was established via Veress needle with CO₂ insufflation maintained at 14 mmHg.

Surgical environment

The surgery was done in a tertiary specialized hospital for women, and the operating rooms are classified as Class III.

Surgical team

The surgical team comprised two board-certified gynecologic oncologists (primary surgeon: >10 years’ advanced laparoscopy experience), two specialized oncology nurses, and an anesthesiologist.

Surgical instrument

A 10-mm 30° standard-length laparoscope, ultrasonic shears, bipolar electrocautery, and other standard laparoscopic surgical instruments.

Ethical statement

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 for publication of this manuscript and accompanying surgical video/images, with patient anonymity preserved.

Step-by-step description

• Step 1: coagulation and transection of the infundibulopelvic ligament.
• Step 2: fenestration of the broad ligaments.
• Step 3: dissection and coagulation of the uterine vessels.
• Step 4: opening of the vaginal wall and extraction of the uterus, absorbable sutures (size 2-0) were used for continuous suturing to close the vaginal stump.
• Step 5: en bloc resection of the enlarged obturator lymph node.
• Step 6: the peritoneum was closed with 2-0 absorbable sutures, and finally the abdominal puncture sites were closed with 4-0 absorbable sutures.

Postoperative considerations and tasks

The surgical duration was 120 minutes and estimated blood loss was 20 mL. Prophylactic antibiotics and intravenous analgesics were administered respectively within 48 and 24 hours after the surgery. Due to severe adhesions around the bladder during the operation and dissected the vesicouterine space intraoperatively, the urinary catheter was removed on postoperative day 2. Early ambulation was encouraged, and pneumatic compression devices were applied to both lower extremities to prevent deep vein thrombosis.

The patient recovered well after surgery. The patient had stable vital signs after surgery, with body temperature maintained at 36.2–37.0 ℃ (normal range) during the postoperative period, no fever, abdominal pain, vaginal abnormal bleeding or other discomfort symptoms, and no surgical-related severe complications such as pelvic infection, massive hemorrhage, urinary tract injury or deep vein thrombosis occurred. The patient’s diet and activity gradually recovered, wound healing was good without redness, swelling, exudation or other abnormal conditions, and the patient was discharged smoothly on the 4th day after surgery. The patient was promptly transferred to the Department of Urology for further management and demonstrated good postoperative recovery following the additional treatment.

Tips and pearls

Precise identification of pelvic anatomical landmarks

A comprehensive understanding of pelvic anatomy is fundamental to ensuring surgical safety. Particular attention should be paid to the accurate identification of the obturator nerve, as well as the external and internal iliac vessels, prior to lymph node dissection.

Strict adherence to anatomical boundaries

The surgical field should be strictly confined within the anatomical space bordered by the external and internal iliac vessels. Precise delineation of this area facilitates safe dissection and minimizes the risk of iatrogenic injury to adjacent structures.

Optimal vascular protection techniques

To reduce the risk of vascular injury during lymph node dissection, blunt dissection is preferred whenever appropriate. In cases of superficial vascular injury, suturing for hemostasis should be prioritized over electrocoagulation to avoid thermal damage and ensure vascular integrity.

Vessel-specific management strategies

The management of vessels adjacent to enlarged lymph nodes requires meticulous surgical technique:

• For veins, gentle traction and displacement using atraumatic laparoscopic instruments are recommended, with particular caution to avoid overstretching or avulsion.
• For arteries, the vessel wall should be securely clamped using appropriate instruments such as a fallopian tube clamp. Care should be taken to minimize shear forces and ensure controlled dissection to prevent arterial injury.

Discussion

Mastery of advanced surgical techniques is essential for gynecologic oncologists to effectively manage the considerable technical challenges and potential risks associated with complex procedures. Laparoscopic surgery has become the preferred and classical approach for retroperitoneal lymphadenectomy. Mastering laparoscopic lymphadenectomy is of critical importance in clinical practice.

In the field of gynecologic oncology surgery, minimally invasive surgical techniques have developed rapidly, among which laparoscopic surgery represents a major breakthrough. In recent years, robot-assisted laparoscopy has emerged as a widely applied and increasingly prevalent minimally invasive surgical approach, utilized in the treatment of endometrial cancer. However, controversies persist regarding the efficacy and safety of different surgical modalities. A randomized controlled trial (7) published in 2025 enrolled 97 patients with gynecologic malignancies, with a follow-up duration of at least 10 years. The results demonstrated that patients with endometrial cancer who underwent robot-assisted laparoscopic surgery exhibited a slightly more pronounced overall survival advantage compared to those who received conventional laparoscopy. Therefore, robot-assisted technology appears to be safe for the treatment of endometrial cancer, although larger-scale randomized controlled trials are still required to confirm its potential survival benefits. Additionally, in the literature related to gynecologic oncology surgery, studies specifically focusing on surgical approaches for lymph node resection are relatively scarce. In terms of complications, a retrospective study (8) reported no statistically significant difference in the incidence of lymphoceles between laparoscopic and open surgeries.

In the surgical treatment of different gynecological malignant tumors or those at different stages, the purpose, scope, and role of lymphadenectomy vary respectively. Issues such as how to judge suspicious or enlarged lymph nodes (especially in laparoscopic surgery where palpation is not feasible and observation requires opening the posterior peritoneum), iatrogenic dissemination during the resection of positive lymph nodes, and the impact of lymphadenectomy on immunotherapy—the resolution of these problems will render the application of lymphadenectomy more precise and safe in gynecological cancer patients (9). Firstly, the removal of clinically suspicious lymph nodes helps confirm or exclude lymphatic metastasis, thereby contributing to accurate disease staging. Secondly, excising lymph nodes without obvious metastatic evidence allows for the detection of potential subclinical metastases. Lastly, in cases where lymph node metastasis is confirmed, their removal serves as part of cytoreductive surgery, eliminating tumor burden and potentially improving the overall prognosis.

The management of enlarged lymph nodes can be technically challenging due to their fragile consistency and complex anatomical location. Fragmentation of these nodes, particularly when the possibility of other malignancies cannot be completely excluded, may lead to tumor cell spillage, resulting in peritoneal implantation or even distant metastasis. Anatomically, enlarged lymph nodes are often closely adherent to the external and internal iliac vessels and may encase the obturator nerve. Accidental injury to the iliac vessels can cause life-threatening hemorrhage that is difficult to control. Similarly, damage to the obturator nerve may result in a range of complications, including impaired adduction of the ipsilateral thigh and the development of reflex pain within the nerve’s sensory distribution area (10).

To effectively mitigate these potential complications, meticulous identification and precise localization of the obturator nerve and the external and internal iliac vessels are paramount before initiating lymph node excision. The standard dissection boundaries for the obturator lymph node packet are defined as follows: superiorly by the external iliac vein, inferiorly by the obturator nerve, cranially by the bifurcation of the common iliac vein, and caudally by the space between the inferior border of the external iliac vein and the pectineal ligament (8). The dissection begins by incising the fascia along the external iliac vein, extending the incision to the intersection of the external iliac vein and the pectineal ligament. The fibrofatty lymphatic tissue is meticulously separated along the inferior margin of the vein, exposing the adventitia of the vein wall and the lateral pelvic wall. Lymphatic clearance is continued inferiorly until reaching the pelvic wall obturator muscle. However, as encountered in the present case, the management of incidentally discovered enlarged lymph nodes necessitates a flexible approach. This involves adhering to the principle of achieving maximal lesion resection while minimizing potential harm to surrounding neurovascular structures. In a nutshell, how to remove the lymph nodes are critical considerations in the management of patients with tumors, closely related to the prognosis of the diseases.

This study focuses on the surgical educational value of laparoscopic en bloc resection for obturator lymph nodes. While the operational demonstration is clear and clinically relevant, the study has notable limitations. First, as a single-case report, it features a small sample size and lacks a control design, which hinders verification of the procedure’s generalizability and safety with insufficient statistical power. Second, postoperative follow-up data are incomplete, failing to specify long-term tumor recurrence, long-term sequelae of neurovascular complications, and dynamic changes in patient quality of life, resulting in inadequate comprehensive outcome assessment. Third, the target population for this surgical approach remains ill-defined, and operational adjustment strategies for complex anatomical variations are lacking, which may restrict its clinical application. Future multi-center case series studies are recommended, supplemented by long-term follow-up data and subgroup analyses, to further refine the standardized surgical protocol and enhance the study’s clinical reference value and educational guiding significance.

Conclusions

The en bloc excision of enlarged lymph nodes remains a critical component in the surgical management of malignant tumors. Incomplete removal of suspicious lymph nodes carries the risk of peritoneal implantation or even distant metastasis. This video demonstrates the surgical management of enlarged obturator lymph nodes as an example for medical education purposes. Despite their fragile texture and complex anatomical location, even significantly enlarged lymph nodes can be safely and effectively excised laparoscopically with the implementation of meticulous surgical techniques and adherence to anatomical principles.

Acknowledgments

The video was awarded the second prize in the Fifth International Elite Gynecologic Surgery Competition (2025 Masters of Gynecologic Surgery).

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Gynecology and Pelvic Medicine for the series “Award-Winning Videos from the Fifth International Elite Gynecologic Surgery Competition (2025 Masters of Gynecologic Surgery)”. The article has undergone external peer review.

Reporting Checklist: The authors have completed the SUPER reporting checklist. Available at https://gpm.amegroups.com/article/view/10.21037/gpm-25-25/rc

Peer Review File: Available at https://gpm.amegroups.com/article/view/10.21037/gpm-25-25/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://gpm.amegroups.com/article/view/10.21037/gpm-25-25/coif). The series “Award-Winning Videos from the Fifth International Elite Gynecologic Surgery Competition (2025 Masters of Gynecologic Surgery)” was commissioned by the editorial office without any funding or sponsorship. J.Z. serves as an unpaid editorial board member of Gynecology and Pelvic Medicine from January 2026 to December 2027.The authors have no other 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 for publication of this manuscript and accompanying surgical video/images, with patient anonymity preserved.

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/.

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