Laparoscopic Visualisation of the Ureters Using Near-Infrared Fluorescence Imaging After Retrograde Indocyanine Green Injection in Deep Infiltrating Endometriosis: The LAVIC Trial

Laparoscopic Visualisation of the Ureters Using Near-Infrared Fluorescence Imaging After Retrograde Indocyanine Green Injection in Deep Infiltrating Endometriosis: The LAVIC Trial | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Laparoscopic Visualisation of the Ureters Using Near-Infrared Fluorescence Imaging After Retrograde Indocyanine Green Injection in Deep Infiltrating Endometriosis: The LAVIC Trial Cloé Vaineau, Bettina Schlatter, Sara Imboden, Anna- Sophie Villiger, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9510556/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Objective: To evaluate the feasibility and safety of intraureteral indocyanine green fluorescence for real-time ureter visualisation during laparoscopic surgery for deep infiltrating endometriosis. Methods: This prospective, single-centre cohort study was conducted at a tertiary referral centre for endometriosis. Premenopausal women with histologically confirmed or clinically highly suspected deep infiltrating endometriosis (DIE) who were scheduled for surgical treatment were eligible for inclusion. After initial laparoscopic inspection, cystoscopy was performed, followed by retrograde intraureteral injection of indocyanine green (ICG). A dose of 25 mg ICG diluted in 5 mL sodium chloride solution was administered into each ureter. Near-infrared fluorescence imaging was subsequently used during laparoscopy to assess ureteral fluorescence and enable real-time visualization. Surgical treatment of DIE, including ureterolysis when required, was performed according to institutional standards. Duration of cystoscopy and ICG-injection, ureter visualization, time to fluorescence, and duration of fluorescence signal were prospectively recorded, along with necessity for ureterolysis as well as relevant patient and surgical characteristics. Results: Fifty-one patients (mean age 36 years) were included. The mean duration of surgery was 217.3 ± 81.1 minutes. The mean duration of cystoscopy was 7.0 ± 5.0 minutes, and intraureteral ICG-injection required 4.3 ± 3.3 minutes. Bilateral ureteral fluorescence was achieved in 50 of 51 patients (98%). Visualisation was immediate in all cases and persisted throughout surgery. Ureterolysis was required in 45% of patients. No ureteral injuries or ICG-related complications occurred. Conclusion: This study confirms the feasibility of intraureteral indocyanine green marking as its primary endpoint. The lack of indocyanine green-, cystoscopy-, or catheterisation-related complications confirms its safety, and the minimal additional procedural time enables routine use while improving intraoperative orientation through real-time ureter visualisation. Endometriosis deep infiltrating indocyanine green ureteral visualisation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Take home messages Cystoscopic intraureteral ICG administration is a feasible technique that provides reliable real-time visualisation of the ureter during laparoscopic surgery for deep infiltrating endometriosis, while requiring only minimal additional operative time. Introduction Endometriosis affects approximately 10% of premenopausal women. The disease manifests in several distinct phenotypes, including superficial peritoneal endometriosis, ovarian endometriomas, and deep infiltrating endometriosis (DIE) ( 1 ). Deep infiltrating endometriosis (DIE) represents the most severe form and affects about 1–2% of women in the general population ( 2 ). However, endometriosis remains substantially underdiagnosed, and diagnostic delay is common, with an average interval of approximately 7 years between symptom onset and definitive diagnosis. This delay is attributed to the heterogeneity of symptoms, normalisation of menstrual pain, limited awareness among both patients and healthcare providers and the diagnostic challenges associated with the variable clinical presentation and limitations of non-invasive diagnostic tools. The resulting diagnostic gap can lead to prolonged suffering, impaired quality of life, and disease progression ( 3 ). Consequently, continued research is essential to improve early recognition, optimise treatment strategies, and better understand the pathophysiology and long-term outcomes of endometriosis. Surgery is frequently required when medical management fails, but resection of DIE remains technically demanding because of its close relationship to vital structures, including the bowel, nerves, major vessels, and the urinary tract. Urinary tract involvement in DIE is common, occurring in 19.5% up to 52% of patients, with the ureter being the second most commonly affected site after the bladder ( 4 , 5 ). While bladder involvement in DIE is usually manageable without major long-term sequelae, ureteral involvement carries risks of silent obstruction, progressive hydronephrosis, and irreversible renal impairment. Because ureteral involvement in DIE may remain clinically silent or show non-specific symptoms, a significant number of cases are only discovered during preoperative diagnostic imaging, sometimes when hydronephrosis or renal impairment has already developed ( 6 , 7 ). Ureterolysis is often required in DIE surgeries, not only to free the ureter due to ureteral endometriosis but also for surgical exposure during rectovaginal, uterosacral, or parametrial dissection. However, ureterolysis is a time-consuming, high-risk procedure associated with mechanical, thermal, and ischemic ureter injuries ( 7 ). Although ureteral injury is rare in benign gynecological surgery (0.4–0.8%), its incidence is significantly higher among patients with endometriosis. Bladder injuries are around three times more common and are usually detected immediately during the operation ( 8 , 9 ). As ureteral injuries are among the most feared complications due to their potential for long-term morbidity, safer alternatives or adjunctive techniques to facilitate ureterolysis or improve ureteral visualisation are highly desirable. Prophylactic double-J stenting has been used in some centres, but it carries morbidity - including pain, dysuria, and hematuria and may increase urinary tract infection risk. Available evidence does not support its use to reduce complications, and it may increase the risk of urinary tract infections ( 7 , 10 ). Indocyanine green (ICG), a fluorescent dye used since 1956 ( 11 ), has gained importance in fluorescence-guided surgery, particularly in perfusion assessment and sentinel lymph node mapping ( 12 , 13 ). ICG provides real-time vessel and perfusion imaging with an excellent safety profile. The application of intraureteral ICG for ureteral visualisation has been reported in gynecologic, urologic, and colorectal surgery ( 12 , 14 – 20 ). Early feasibility studies investigating ICG imaging in endometriosis have been reported, although they were limited to small cohorts ( 15 , 16 ). This study aims to evaluate the feasibility of intraureteral ICG injection for real-time fluorescent ureter visualisation during minimally invasive surgery in deep infiltrating endometriosis. Materials and Methods This prospective, single-arm, single-centre study included premenopausal patients who underwent minimally invasive surgical treatment for histologically proven or highly suspected DIE at the certified endometriosis centre, University Hospital Bern, Switzerland. All patients provided written informed consent. The enrolment period was between June 2023 and September 2024. Exclusion criteria were iodine, shellfish or ICG allergy, hyperthyroidism, severe renal insufficiency, beta-blocker treatment, pregnancy, breastfeeding, untreated urinary tract infection, pyelonephritis, prior ureteral reimplantation or nephrostomy, or prior pelvic radiotherapy. Preoperative assessment included medical history and symptoms, including pain severity assessed using a visual analogue scale (VAS), clinical examination, structured transvaginal ultrasound following IDEA criteria ( 21 ), renal sonography, urine analysis, and MRI when indicated. As part of standard practice at our institution, all patients are required to sign a procedure-specific consent form for endometriosis surgery, in which the potential extent of surgery and available operative options are discussed in advance. This ensures that all potential surgical scenarios have been thoroughly discussed in advance and that the procedure performed aligns precisely with the patient’s preferences. Diagnostic laparoscopy was performed at the beginning of surgery to confirm or exclude DIE. Upon confirmation of DIE, cystoscopy with retrograde intraureteral injection of 25 mg ICG (Verdye®) dissolved in 5 ml NaCl was performed bilaterally using a 5 French ureteral catheter (refer to Figs. 1 and 2 ). Time of cystoscopy, as well as time until visualisation of fluorescing ureters, and the duration of fluorescence of the ICG-labelled ureters were measured and documented. Real-time visualisation of ICG during minimally invasive surgery was performed with a 4K NIR/ICG camera system from Karl Storz. Intraoperative images are available in the appendix (see Figs. 3 – 5 ). Intra- and postoperative adverse events were recorded. Details of the procedures performed, as well as the endometriosis stage according to #ENZIAN and rASRM, were documented. Board-certified endometriosis surgeons performed all procedures. All data were recorded in an anonymised database, and the statistical analysis was performed using IBM SPSS Statistics. The relevant ethics committee (Project ID 2021 − 02010) approved the project, and the use of intraureteral ICG was approved by Swissmedic, the national committee for medical substances and devices. The trial protocol is registered at clinicatrials.gov, NCT05206279. Results A total of 85 patients were screened, of which 51 were included in this study. Thirty-four patients were excluded due to the absence of DIE (n = 25), preoperative urinary infection (n = 1), surgery cancellation (n = 1), or incomplete documentation (n = 7). Table 1 shows a detailed description of the main clinical characteristics of the patient cohort. Mean age was 36.1 (SD ± 6.4) years with a mean BMI of 25.95 ± 5.06 kg/m². Indications for surgery mainly included pain, followed by infertility and, less frequently, threatened organ function. Reported symptoms comprised dysmenorrhea (94.1%), dyspareunia (72.5%), dyschezia (62.7%), dysuria (23.5%), chronic pelvic pain (70.6%), and infertility (29.5%). At the time of surgery, most patients were receiving hormonal treatment, primarily gestagen therapy (54.9%). A considerable number of patients were not on hormonal therapy (29.5%), mainly due to the desire to conceive. Table 1 General and clinical characteristics Variable n (%) or value Range Demographic data Age (years) 36.4 ± 6.1 26.0–53.0 BMI (kg/m²) 26.0 ± 5.1 19.0–38.8 Indication for surgery Pain 36 (70.6) Pain & infertility 14 (27.5) Endangered organ 1 (2.0) (kidney) Patient symptoms Dysmenorrhoea 48 (94.1) Dyspareunia 37 (72.6) Dyschezia 32 (62.7) Dysuria 12 (23.5) Acyclic pain / chronic pelvic pain 36 (70.6) Infertility 15 (29.4) Pregnancy history Number of pregnancies (total) 49 (in 23 patients) Vaginal deliveries 19, in 12 patients (38.8) Caesarean sections 16, in 12 patients (32.6) Pregnancy loss 14, in 8 patients (28.6) History of infertility 15 (29.4) Mode of diagnosis of DIE Symptoms 50 (98) Ultrasound (IDEA) 25 (49.0) MRI 48 (94.1) Previous operation with diagnosis of DIE 22 (43.1) Previous surgeries Previous surgery for endometriosis 27 (52.9) Previous abdominal surgery (other reasons) 18 (35.3) Previous hormonal treatment Previous COC treatment 25 (49.0) Previous gestagen treatment 26 (51.0) Previous GnRHa treatment 5 (9.8) Previous LNG-IUD treatment 4 (7.8) Current hormonal treatment COC treatment 2 (3.9) Gestagen (POP) treatment 28 (54.9) GnRHa treatment 4 (7.8) LNG-IUD treatment 2 (3.9) No hormonal treatment 15 (29.5) The mean duration of surgery was 217.3 ± 81.1 minutes, with an average estimated blood loss of 124.3 ± 109.8 ml. Intestinal surgery occurred in 58.8% of patients. Ovarian surgery was performed in 66.7%, hysterectomy in 39.2%, colpotomy in 43.1%, and peritoneal endometriosis excision in 70.6% of patients. Table 2 summarises the main surgical data, and Fig. 8 provides information on the stage of endometriosis. Table 2 Intraoperative procedures Procedure n (%) or value Ureterolysis performed 23 (45.1) - Left ureterolysis (number of ureters) 22 - Right ureterolysis (number of ureters) 17 - Length of ureterolysis (cm) per ureter, mean ± SD (range) 3.6 ± 2.3 cm Bladder shaving 4 (7.8) Bladder excision 1 (2.0) Excision of peritoneal endometriosis 36 (70.6) Excision of deep infiltrating endometriosis (DIE) 50 (98.0) Hysterectomy 20 (39.2) Opening of the vagina (colpotomy) 22 (43.1) Intestinal surgery 30 (58.8) - Shaving 20 (39.2) - Disc excision 4 (21.6) - Segmental resection - other 11 (21.6) 2 (3.9), appendectomy Ureter excision 0 (0) UCNS performed 0 (0) Ovarian surgery 35 (68.6) Ovarian cystectomy 23 (45.1) Tubal surgery 34 (66.7) On average, cystoscopy lasted 7 minutes (SD ± 5 minutes), and the mean duration of ICG marking was 4.3 minutes (SD ± 3.3 minutes). ICG ureteral detection was successful in 101 out of 102 (99%) ureters, resulting in a 98% success rate for bilateral ureteral marking. Fluorescence was immediate in all cases and persisted throughout surgery. In 45.1% of patients, ureterolysis was required, with 22 on the left and 17 on the right. The mean length of the ureterolysis, measured using a laparoscopic forceps, was 3.6 ± 2.3 cm per ureter. No ureter excision or uretero-cysto-neostomia was necessary. Bladder shaving was performed in 7.8%, and partial excision in 2%. No intra- or postoperative ureter injuries or ICG-related complications occurred in our cohort. Postoperative complications were reported in 4 patients, as classified by the Clavien-Dindo classification ( 22 ). One patient had a urinary infection on day 6 after the operation. A vaginal infection occurred in one patient and a transient voiding problem with temporary self-catheterisation in another patient. One patient suffered a paralytic ileus, a lung embolism despite adequate thromboprophylaxis, which a diagnosed COVID-19 pneumonia may have caused. All complications were successfully treated with medication or self-catheterisation (Grade II according to the Clavien-Dindo Classification). There were no surgical re-interventions in the study cohort, and no ICG-related or study-specific complications were reported. Discussion Surgical management of deep infiltrating endometriosis can be technically demanding, particularly in cases with significant distortion of normal pelvic anatomy. The ureters constitute a critical anatomical structure in complex endometriosis surgery, as injury may result in substantial morbidity with potentially long-term consequences. Consequently, ureterolysis is frequently required to achieve adequate exposure and enable safe and complete resection of endometriotic lesions. This study demonstrates that intraureteral ICG is a safe and feasible method for real-time ureteral visualisation during complex DIE surgery. No side effects attributable to ICG were detected. Our 98% bilateral fluorescence rate aligns with findings from prior smaller cohorts ( 15 , 16 ). One ureter could not be visualised intraoperatively, despite inconspicuous cystoscopic marking. The patient was obese, had a myomatous uterus, and a deep infiltrating nodule of the rectum without involvement of the lateral compartment and/or ureteral involvement. Thus, the underlying reason for the failed ureteral catheterisation remained unclear. However, given our experience with ICG, an application issue seems more likely than a technical failure of the ICG itself. To date, several studies have investigated the use of intraureteral ICG in minimally invasive pelvic surgery, consistently demonstrating an excellent safety profile ( 14 – 20 , 23 ). Early feasibility studies typically included small cohorts and the available data regarding deep infiltrating endometriosis remains limited. A recently published study by Centini et al. ( 16 ) employed a similar protocol, including 10 patients who underwent intraureteral ICG administration. While the authors suggested that ICG fluorescence may reduce the need for ureterolysis, the small cohort size limits generalizability, and larger studies are required to confirm these findings. Another study assessed the feasibility of ICG-guided ureter visualisation during robotic transvaginal endometriosis resection. The cohort predominantly comprised patients with early-stage or peritoneal disease, demonstrating high feasibility and no procedure-related complications ( 15 ). Similar findings were reported in an earlier study evaluating the utility of ICG-based ureter visualisation across various pelvic procedures, including colorectal and pelvic organ prolapse surgeries ( 17 – 19 ). Within our study, we additionally evaluated the procedural time required for cystoscopy and intraureteral ICG administration - parameters that have not been systematically assessed in the existing literature. The mean additional time was seven minutes for cystoscopy and 4.3 minutes for intraureteral ICG administration. In the context of a mean operative duration of 3.5 hours for highly complex procedures, this incremental time appears negligible. Improved ureter visualisation may potentially contribute to a reduction in operative time; however, the absence of a control group precludes validation of this hypothesis. Furthermore, to our knowledge, this is the first study to evaluate the extent of ureterolysis required. The observed mean ureterolysis length of 3.6 cm may indicate a reduction associated with ICG visualisation, given that ureterolysis is conventionally performed from the pelvic brim to its parametrial course. Nevertheless, this observation remains speculative in the absence of a control group. Ureterolysis is required in a substantial proportion of DIE surgeries, and fluorescence guidance may reduce the extent of dissection, thereby potentially lowering the risk of ureteral injury and minimising disruption to ureteral vascularity. Compared with prophylactic double-J stenting, intraureteral ICG avoids patient discomfort while providing actionable, real-time intraoperative visualisation. Importantly, a key advantage of this approach is its intraoperative applicability, allowing selective use only when indicated, in contrast to more invasive preoperative measures such as double-J stenting. Future studies incorporating control groups are warranted to determine whether fluorescence guidance reduces the need for ureterolysis, the incidence of ureteral injury, and operative time, and to assess the cost-effectiveness of ICG-based ureter visualisation. However, the low incidence of ureteral injuries and the substantial variability in surgical complexity—including the highly variable extent of ureterolysis required—are likely to limit statistical power and necessitate large sample sizes. Nevertheless, given the established safety profile, minimal additional operative time, and ease of implementation, intraoperative ICG-based ureter visualisation may be considered for integration into standard practice in complex endometriosis surgery. Strengths and limitations To our knowledge, this study represents the largest published series of patients with surgically confirmed deep infiltrating endometriosis undergoing intraureteral ICG-guided laparoscopy. This well-defined, homogeneous, high-complexity population reflects the clinical setting in which reliable ureter visualisation is most critical. Furthermore, this study is the first to evaluate the additional time required for cystoscopy and intraureteral ICG administration, and to systematically document the extent of ureterolysis performed. Our results confirm the feasibility and persistence of fluorescence in nearly all cases, underscoring the robustness of the technique even in anatomically challenging conditions. Major limitations include the single-arm design without a control group and variability in surgical complexity. Conclusions This study confirms the feasibility of intraureteral ICG marking, as defined by its primary endpoint. The absence of complications related to cystoscopy, ureteral catheterisation, or ICG administration, together with ICG's well-established safety profile, supports the safety of this technique. Given the minimal additional procedural time, the method can be easily integrated into routine clinical practice. It enables immediate, continuous, real-time visualisation of the ureters, thereby enhancing intraoperative orientation and potentially contributing to safer surgery in patients with complex deep infiltrating endometriosis. visualisation Declarations Declaration of Interest The authors reported no potential conflict of interest. Author Contribution Vaineau C: Protocol/project development, Data collection or management, Data analysis, Manuscript writing/editing Schlatter B: Protocol/project development, Data collection or management, Data analysis, Manuscript writing/editing Imboden S: Data analysis, Manuscript editing Villiger A: Data collection or management Gulz M: Data collection or management Mueller MD: Protocol/project development, Manuscript editing Siegenthaler F: Protocol/project development, Manuscript editing The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. The authors declare that they have no conflict of interest. This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the local Ethics Committee (Kantonale Ethikkomission Bern) (Project ID 2021-02010). The use of intraureteral ICG was approved by Swissmedic, the national committee for medical substances and devices. The trial protocol is registered at clinicatrials.gov, NCT05206279. Informed consent was obtained from all individual participants included in the study. Competing Interests : The authors have no relevant financial or non-financial interests to disclose. Funding: The material costs associated with the study and the applications were funded from internal research grants and did not receive any external or company-specific funding. The work carried out by the staff members was not remunerated. References Zondervan TK, Becker MC, Missmer AS. Endometriosis. New England Journal of Medicine. 2020;382(13):1244-56. 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Novel Use of Indocyanine Green for Intraoperative, Real-time Localization of Ureter During Robot-Assisted Excision of Endometriosis. Journal of Minimally Invasive Gynecology. 2015;22(6):S69. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 08 May, 2026 Reviewers invited by journal 06 May, 2026 Editor assigned by journal 29 Apr, 2026 Submission checks completed at journal 29 Apr, 2026 First submitted to journal 23 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9510556","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":636883275,"identity":"1b6711be-f941-4101-b327-c2938d124cca","order_by":0,"name":"Cloé Vaineau","email":"","orcid":"","institution":"University Hospital of Bern, University of Bern","correspondingAuthor":false,"prefix":"","firstName":"Cloé","middleName":"","lastName":"Vaineau","suffix":""},{"id":636883276,"identity":"b0ad6998-602a-4939-978d-f0d8caec276d","order_by":1,"name":"Bettina 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of the ureter\u003c/p\u003e","description":"","filename":"figure1300dpi.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9510556/v1/945c80b543dbca8fc70782f4.jpg"},{"id":109331520,"identity":"9d2df87e-7cd1-44ef-a9e8-71467c0e55a3","added_by":"auto","created_at":"2026-05-15 16:09:43","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":18173,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eafter removing the catheter\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"figure2300dpi.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9510556/v1/3776ad9a6849512e1cbba9d3.jpg"},{"id":109331660,"identity":"22c79425-0112-4d9d-80a9-d4938b7718d7","added_by":"auto","created_at":"2026-05-15 16:09:55","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":615463,"visible":true,"origin":"","legend":"\u003cp\u003eperiureteric node\u003c/p\u003e","description":"","filename":"figure3300dpi.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9510556/v1/32e1930698b79b06bb855ff8.jpg"},{"id":109331519,"identity":"6ebc15a1-87b9-4cbb-b2e9-e1a78c893e54","added_by":"auto","created_at":"2026-05-15 16:09:43","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":92452,"visible":true,"origin":"","legend":"\u003cp\u003eafter ureterolysis\u003c/p\u003e","description":"","filename":"figure4300dpi.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9510556/v1/9360909e8a39427198e9d611.jpg"},{"id":109331661,"identity":"ae581523-50da-4320-a08e-e9d3912b6ce6","added_by":"auto","created_at":"2026-05-15 16:09:55","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":77128,"visible":true,"origin":"","legend":"\u003cp\u003eICG-guided surgery\u003c/p\u003e","description":"","filename":"figure5300dpi.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9510556/v1/41e8cd6b541634d85f357e1a.jpg"},{"id":109331518,"identity":"fef06fcb-995f-44ef-8438-4f4b38392bcb","added_by":"auto","created_at":"2026-05-15 16:09:43","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":79525,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003erASM and\u003c/strong\u003eEnzian classification\u003c/p\u003e","description":"","filename":"figure6300dpi.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9510556/v1/c8a1b5cea0f1ec1b8bc5670b.jpg"},{"id":109331707,"identity":"5d97a61a-1499-4e2e-b34a-0bd85524958e","added_by":"auto","created_at":"2026-05-15 16:10:02","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1265990,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9510556/v1/aed386a2-ed55-4358-b096-a7a35982bd98.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Laparoscopic Visualisation of the Ureters Using Near-Infrared Fluorescence Imaging After Retrograde Indocyanine Green Injection in Deep Infiltrating Endometriosis: The LAVIC Trial","fulltext":[{"header":"Take home messages","content":"\u003cp\u003eCystoscopic intraureteral ICG administration is a feasible technique that provides reliable real-time visualisation of the ureter during laparoscopic surgery for deep infiltrating endometriosis, while requiring only minimal additional operative time.\u003c/p\u003e"},{"header":"Introduction","content":"\u003cp\u003eEndometriosis affects approximately 10% of premenopausal women. The disease manifests in several distinct phenotypes, including superficial peritoneal endometriosis, ovarian endometriomas, and deep infiltrating endometriosis (DIE) (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Deep infiltrating endometriosis (DIE) represents the most severe form and affects about 1\u0026ndash;2% of women in the general population (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). However, endometriosis remains substantially underdiagnosed, and diagnostic delay is common, with an average interval of approximately 7 years between symptom onset and definitive diagnosis. This delay is attributed to the heterogeneity of symptoms, normalisation of menstrual pain, limited awareness among both patients and healthcare providers and the diagnostic challenges associated with the variable clinical presentation and limitations of non-invasive diagnostic tools. The resulting diagnostic gap can lead to prolonged suffering, impaired quality of life, and disease progression (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Consequently, continued research is essential to improve early recognition, optimise treatment strategies, and better understand the pathophysiology and long-term outcomes of endometriosis. Surgery is frequently required when medical management fails, but resection of DIE remains technically demanding because of its close relationship to vital structures, including the bowel, nerves, major vessels, and the urinary tract.\u003c/p\u003e \u003cp\u003eUrinary tract involvement in DIE is common, occurring in 19.5% up to 52% of patients, with the ureter being the second most commonly affected site after the bladder (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). While bladder involvement in DIE is usually manageable without major long-term sequelae, ureteral involvement carries risks of silent obstruction, progressive hydronephrosis, and irreversible renal impairment. Because ureteral involvement in DIE may remain clinically silent or show non-specific symptoms, a significant number of cases are only discovered during preoperative diagnostic imaging, sometimes when hydronephrosis or renal impairment has already developed (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). Ureterolysis is often required in DIE surgeries, not only to free the ureter due to ureteral endometriosis but also for surgical exposure during rectovaginal, uterosacral, or parametrial dissection. However, ureterolysis is a time-consuming, high-risk procedure associated with mechanical, thermal, and ischemic ureter injuries (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). Although ureteral injury is rare in benign gynecological surgery (0.4\u0026ndash;0.8%), its incidence is significantly higher among patients with endometriosis. Bladder injuries are around three times more common and are usually detected immediately during the operation (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAs ureteral injuries are among the most feared complications due to their potential for long-term morbidity, safer alternatives or adjunctive techniques to facilitate ureterolysis or improve ureteral visualisation are highly desirable. Prophylactic double-J stenting has been used in some centres, but it carries morbidity - including pain, dysuria, and hematuria and may increase urinary tract infection risk. Available evidence does not support its use to reduce complications, and it may increase the risk of urinary tract infections (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Indocyanine green (ICG), a fluorescent dye used since 1956 (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e), has gained importance in fluorescence-guided surgery, particularly in perfusion assessment and sentinel lymph node mapping (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). ICG provides real-time vessel and perfusion imaging with an excellent safety profile. The application of intraureteral ICG for ureteral visualisation has been reported in gynecologic, urologic, and colorectal surgery (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan additionalcitationids=\"CR15 CR16 CR17 CR18 CR19\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e). Early feasibility studies investigating ICG imaging in endometriosis have been reported, although they were limited to small cohorts (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). This study aims to evaluate the feasibility of intraureteral ICG injection for real-time fluorescent ureter visualisation during minimally invasive surgery in deep infiltrating endometriosis.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eThis prospective, single-arm, single-centre study included premenopausal patients who underwent minimally invasive surgical treatment for histologically proven or highly suspected DIE at the certified endometriosis centre, University Hospital Bern, Switzerland. All patients provided written informed consent. The enrolment period was between June 2023 and September 2024. Exclusion criteria were iodine, shellfish or ICG allergy, hyperthyroidism, severe renal insufficiency, beta-blocker treatment, pregnancy, breastfeeding, untreated urinary tract infection, pyelonephritis, prior ureteral reimplantation or nephrostomy, or prior pelvic radiotherapy.\u003c/p\u003e \u003cp\u003ePreoperative assessment included medical history and symptoms, including pain severity assessed using a visual analogue scale (VAS), clinical examination, structured transvaginal ultrasound following IDEA criteria (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e), renal sonography, urine analysis, and MRI when indicated. As part of standard practice at our institution, all patients are required to sign a procedure-specific consent form for endometriosis surgery, in which the potential extent of surgery and available operative options are discussed in advance. This ensures that all potential surgical scenarios have been thoroughly discussed in advance and that the procedure performed aligns precisely with the patient\u0026rsquo;s preferences.\u003c/p\u003e \u003cp\u003eDiagnostic laparoscopy was performed at the beginning of surgery to confirm or exclude DIE. Upon confirmation of DIE, cystoscopy with retrograde intraureteral injection of 25 mg ICG (Verdye\u0026reg;) dissolved in 5 ml NaCl was performed bilaterally using a 5 French ureteral catheter (refer to Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Time of cystoscopy, as well as time until visualisation of fluorescing ureters, and the duration of fluorescence of the ICG-labelled ureters were measured and documented. Real-time visualisation of ICG during minimally invasive surgery was performed with a 4K NIR/ICG camera system from Karl Storz. Intraoperative images are available in the appendix (see Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Intra- and postoperative adverse events were recorded. Details of the procedures performed, as well as the endometriosis stage according to #ENZIAN and rASRM, were documented. Board-certified endometriosis surgeons performed all procedures.\u003c/p\u003e \u003cp\u003eAll data were recorded in an anonymised database, and the statistical analysis was performed using IBM SPSS Statistics.\u003c/p\u003e \u003cp\u003e The relevant ethics committee (Project ID 2021\u0026thinsp;\u0026minus;\u0026thinsp;02010) approved the project, and the use of intraureteral ICG was approved by Swissmedic, the national committee for medical substances and devices. The trial protocol is registered at clinicatrials.gov, NCT05206279.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 85 patients were screened, of which 51 were included in this study. Thirty-four patients were excluded due to the absence of DIE (n\u0026thinsp;=\u0026thinsp;25), preoperative urinary infection (n\u0026thinsp;=\u0026thinsp;1), surgery cancellation (n\u0026thinsp;=\u0026thinsp;1), or incomplete documentation (n\u0026thinsp;=\u0026thinsp;7).\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows a detailed description of the main clinical characteristics of the patient cohort. Mean age was 36.1 (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;6.4) years with a mean BMI of 25.95\u0026thinsp;\u0026plusmn;\u0026thinsp;5.06 kg/m\u0026sup2;. Indications for surgery mainly included pain, followed by infertility and, less frequently, threatened organ function. Reported symptoms comprised dysmenorrhea (94.1%), dyspareunia (72.5%), dyschezia (62.7%), dysuria (23.5%), chronic pelvic pain (70.6%), and infertility (29.5%). At the time of surgery, most patients were receiving hormonal treatment, primarily gestagen therapy (54.9%). A considerable number of patients were not on hormonal therapy (29.5%), mainly due to the desire to conceive.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eGeneral and clinical characteristics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en (%) or value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDemographic data\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36.4\u0026thinsp;\u0026plusmn;\u0026thinsp;6.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26.0\u0026ndash;53.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m\u0026sup2;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26.0\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19.0\u0026ndash;38.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIndication for surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36 (70.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePain \u0026amp; infertility\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (27.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEndangered organ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(kidney)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePatient symptoms\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDysmenorrhoea\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e48 (94.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDyspareunia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e37 (72.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDyschezia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e32 (62.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDysuria\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (23.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAcyclic pain / chronic pelvic pain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36 (70.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInfertility\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (29.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePregnancy history\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of pregnancies (total)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e49 (in 23 patients)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVaginal deliveries\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19, in 12 patients (38.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCaesarean sections\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16, in 12 patients (32.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePregnancy loss\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14, in 8 patients (28.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHistory of infertility\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (29.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMode of diagnosis of DIE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSymptoms\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50 (98)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUltrasound (IDEA)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25 (49.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMRI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e48 (94.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious operation with diagnosis of DIE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22 (43.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious surgeries\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious surgery for endometriosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27 (52.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious abdominal surgery (other reasons)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (35.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious hormonal treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious COC treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25 (49.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious gestagen treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26 (51.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious GnRHa treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (9.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious LNG-IUD treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (7.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCurrent hormonal treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCOC treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (3.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGestagen (POP) treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28 (54.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGnRHa treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (7.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLNG-IUD treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (3.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo hormonal treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (29.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe mean duration of surgery was 217.3\u0026thinsp;\u0026plusmn;\u0026thinsp;81.1 minutes, with an average estimated blood loss of 124.3\u0026thinsp;\u0026plusmn;\u0026thinsp;109.8 ml. Intestinal surgery occurred in 58.8% of patients. Ovarian surgery was performed in 66.7%, hysterectomy in 39.2%, colpotomy in 43.1%, and peritoneal endometriosis excision in 70.6% of patients. Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e summarises the main surgical data, and Fig.\u0026nbsp;8 provides information on the stage of endometriosis.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eIntraoperative procedures\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProcedure\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en (%) or value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUreterolysis performed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23 (45.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e- Left ureterolysis (number of ureters)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e- Right ureterolysis (number of ureters)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e- Length of ureterolysis (cm) per ureter, mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD (range)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3 cm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBladder shaving\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (7.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBladder excision\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExcision of peritoneal endometriosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36 (70.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExcision of deep infiltrating endometriosis (DIE)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50 (98.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHysterectomy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20 (39.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOpening of the vagina (colpotomy)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22 (43.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntestinal surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30 (58.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e- Shaving\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20 (39.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e- Disc excision\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (21.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e- Segmental resection\u003c/p\u003e \u003cp\u003e- other\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11 (21.6)\u003c/p\u003e \u003cp\u003e2 (3.9), appendectomy\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUreter excision\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUCNS performed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvarian surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e35 (68.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvarian cystectomy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23 (45.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTubal surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e34 (66.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eOn average, cystoscopy lasted 7 minutes (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;5 minutes), and the mean duration of ICG marking was 4.3 minutes (SD\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3 minutes). ICG ureteral detection was successful in 101 out of 102 (99%) ureters, resulting in a 98% success rate for bilateral ureteral marking. Fluorescence was immediate in all cases and persisted throughout surgery. In 45.1% of patients, ureterolysis was required, with 22 on the left and 17 on the right. The mean length of the ureterolysis, measured using a laparoscopic forceps, was 3.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3 cm per ureter. No ureter excision or uretero-cysto-neostomia was necessary. Bladder shaving was performed in 7.8%, and partial excision in 2%. No intra- or postoperative ureter injuries or ICG-related complications occurred in our cohort.\u003c/p\u003e \u003cp\u003ePostoperative complications were reported in 4 patients, as classified by the Clavien-Dindo classification (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e). One patient had a urinary infection on day 6 after the operation. A vaginal infection occurred in one patient and a transient voiding problem with temporary self-catheterisation in another patient. One patient suffered a paralytic ileus, a lung embolism despite adequate thromboprophylaxis, which a diagnosed COVID-19 pneumonia may have caused. All complications were successfully treated with medication or self-catheterisation (Grade II according to the Clavien-Dindo Classification). There were no surgical re-interventions in the study cohort, and no ICG-related or study-specific complications were reported.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eSurgical management of deep infiltrating endometriosis can be technically demanding, particularly in cases with significant distortion of normal pelvic anatomy. The ureters constitute a critical anatomical structure in complex endometriosis surgery, as injury may result in substantial morbidity with potentially long-term consequences. Consequently, ureterolysis is frequently required to achieve adequate exposure and enable safe and complete resection of endometriotic lesions.\u003c/p\u003e \u003cp\u003eThis study demonstrates that intraureteral ICG is a safe and feasible method for real-time ureteral visualisation during complex DIE surgery. No side effects attributable to ICG were detected. Our 98% bilateral fluorescence rate aligns with findings from prior smaller cohorts (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). One ureter could not be visualised intraoperatively, despite inconspicuous cystoscopic marking. The patient was obese, had a myomatous uterus, and a deep infiltrating nodule of the rectum without involvement of the lateral compartment and/or ureteral involvement. Thus, the underlying reason for the failed ureteral catheterisation remained unclear. However, given our experience with ICG, an application issue seems more likely than a technical failure of the ICG itself.\u003c/p\u003e \u003cp\u003eTo date, several studies have investigated the use of intraureteral ICG in minimally invasive pelvic surgery, consistently demonstrating an excellent safety profile (\u003cspan additionalcitationids=\"CR15 CR16 CR17 CR18 CR19\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e). Early feasibility studies typically included small cohorts and the available data regarding deep infiltrating endometriosis remains limited. A recently published study by Centini et al. (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e) employed a similar protocol, including 10 patients who underwent intraureteral ICG administration. While the authors suggested that ICG fluorescence may reduce the need for ureterolysis, the small cohort size limits generalizability, and larger studies are required to confirm these findings. Another study assessed the feasibility of ICG-guided ureter visualisation during robotic transvaginal endometriosis resection. The cohort predominantly comprised patients with early-stage or peritoneal disease, demonstrating high feasibility and no procedure-related complications (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). Similar findings were reported in an earlier study evaluating the utility of ICG-based ureter visualisation across various pelvic procedures, including colorectal and pelvic organ prolapse surgeries (\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWithin our study, we additionally evaluated the procedural time required for cystoscopy and intraureteral ICG administration - parameters that have not been systematically assessed in the existing literature. The mean additional time was seven minutes for cystoscopy and 4.3 minutes for intraureteral ICG administration. In the context of a mean operative duration of 3.5 hours for highly complex procedures, this incremental time appears negligible. Improved ureter visualisation may potentially contribute to a reduction in operative time; however, the absence of a control group precludes validation of this hypothesis. Furthermore, to our knowledge, this is the first study to evaluate the extent of ureterolysis required. The observed mean ureterolysis length of 3.6 cm may indicate a reduction associated with ICG visualisation, given that ureterolysis is conventionally performed from the pelvic brim to its parametrial course. Nevertheless, this observation remains speculative in the absence of a control group.\u003c/p\u003e \u003cp\u003eUreterolysis is required in a substantial proportion of DIE surgeries, and fluorescence guidance may reduce the extent of dissection, thereby potentially lowering the risk of ureteral injury and minimising disruption to ureteral vascularity. Compared with prophylactic double-J stenting, intraureteral ICG avoids patient discomfort while providing actionable, real-time intraoperative visualisation. Importantly, a key advantage of this approach is its intraoperative applicability, allowing selective use only when indicated, in contrast to more invasive preoperative measures such as double-J stenting. Future studies incorporating control groups are warranted to determine whether fluorescence guidance reduces the need for ureterolysis, the incidence of ureteral injury, and operative time, and to assess the cost-effectiveness of ICG-based ureter visualisation. However, the low incidence of ureteral injuries and the substantial variability in surgical complexity\u0026mdash;including the highly variable extent of ureterolysis required\u0026mdash;are likely to limit statistical power and necessitate large sample sizes. Nevertheless, given the established safety profile, minimal additional operative time, and ease of implementation, intraoperative ICG-based ureter visualisation may be considered for integration into standard practice in complex endometriosis surgery.\u003c/p\u003e\n\u003ch3\u003eStrengths and limitations\u003c/h3\u003e\n\u003cp\u003eTo our knowledge, this study represents the largest published series of patients with surgically confirmed deep infiltrating endometriosis undergoing intraureteral ICG-guided laparoscopy. This well-defined, homogeneous, high-complexity population reflects the clinical setting in which reliable ureter visualisation is most critical. Furthermore, this study is the first to evaluate the additional time required for cystoscopy and intraureteral ICG administration, and to systematically document the extent of ureterolysis performed. Our results confirm the feasibility and persistence of fluorescence in nearly all cases, underscoring the robustness of the technique even in anatomically challenging conditions. Major limitations include the single-arm design without a control group and variability in surgical complexity.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThis study confirms the feasibility of intraureteral ICG marking, as defined by its primary endpoint. The absence of complications related to cystoscopy, ureteral catheterisation, or ICG administration, together with ICG's well-established safety profile, supports the safety of this technique. Given the minimal additional procedural time, the method can be easily integrated into routine clinical practice. It enables immediate, continuous, real-time visualisation of the ureters, thereby enhancing intraoperative orientation and potentially contributing to safer surgery in patients with complex deep infiltrating endometriosis. visualisation\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eDeclaration of Interest\u003c/p\u003e\n\u003cp\u003eThe authors reported no potential conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eVaineau C: Protocol/project development, Data collection or management, Data analysis, Manuscript writing/editing\u003c/p\u003e\n\u003cp\u003eSchlatter B: Protocol/project development, Data collection or management, Data analysis, Manuscript writing/editing\u003c/p\u003e\n\u003cp\u003eImboden S: Data analysis, Manuscript editing\u003c/p\u003e\n\u003cp\u003eVilliger A: Data collection or management\u003c/p\u003e\n\u003cp\u003eGulz M: Data collection or management\u003c/p\u003e\n\u003cp\u003eMueller MD: Protocol/project development, Manuscript editing\u003c/p\u003e\n\u003cp\u003eSiegenthaler F: Protocol/project development, Manuscript editing\u003c/p\u003e\n\u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript. The authors declare that they have no conflict of interest. This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the local Ethics Committee (Kantonale Ethikkomission Bern) (Project ID 2021-02010). The use of intraureteral ICG was approved by Swissmedic, the national committee for medical substances and devices. The trial protocol is registered at clinicatrials.gov, NCT05206279. Informed consent was obtained from all individual participants included in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e: The authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e The material costs associated with the study and the applications were funded from internal research grants and did not receive any external or company-specific funding. The work carried out by the staff members was not remunerated.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eZondervan TK, Becker MC, Missmer AS. Endometriosis. New England Journal of Medicine. 2020;382(13):1244-56.\u003c/li\u003e\n\u003cli\u003eKoninckx RP, Ussia A, Adamyan L, Wattiez A, Donnez J. Deep endometriosis: definition, diagnosis, and treatment. Fertility and Sterility. 2012;98(3):564-71.\u003c/li\u003e\n\u003cli\u003eDe Corte P, Klinghardt M, von Stockum S, Heinemann K. Time to Diagnose Endometriosis: Current Status, Challenges and Regional Characteristics-A Systematic Literature Review. BJOG. 2025;132(2):118-30.\u003c/li\u003e\n\u003cli\u003eGabriel B, Nassif J, Trompoukis P, Barata S, Wattiez A. Prevalence and management of urinary tract endometriosis: a clinical case series. Urology. 2011;78(6):1269-74.\u003c/li\u003e\n\u003cli\u003eKnabben L, Imboden S, Fellmann B, Nirgianakis K, Kuhn A, Mueller MD. Urinary tract endometriosis in patients with deep infiltrating endometriosis: prevalence, symptoms, management, and proposal for a new clinical classification. Fertil Steril. 2015;103(1):147-52.\u003c/li\u003e\n\u003cli\u003eBarra F, Scala C, Biscaldi E, Vellone GV, Ceccaroni M, Terrone C, et al. Ureteral endometriosis: a systematic review of epidemiology, pathogenesis, diagnosis, treatment, risk of malignant transformation and fertility. Human Reproduction Update. 2018;24(6):710-30.\u003c/li\u003e\n\u003cli\u003eChatroux RL, Einarsson IJ. Keep your attention closer to the ureters: Ureterolysis in deep endometriosis surgery. Best Practice \u0026amp; Research Clinical Obstetrics \u0026amp; Gynaecology. 2024;95:102494.\u003c/li\u003e\n\u003cli\u003eWong KMJ, Bortoletto P, Tolentino J, Jung JM, Milad PM. Urinary Tract Injury in Gynecologic Laparoscopy for Benign Indication. Obstetrics \u0026amp; Gynecology. 2018;131(1):100-8.\u003c/li\u003e\n\u003cli\u003eDickson B, Tessier MK, Green CI, Cope GA, Fok SC, Hutto LS, et al. Urinary Tract Injury During Benign Hysterectomy for Endometriosis: An NSQIP Study. Journal of Minimally Invasive Gynecology. 2025;32(10):898-905.e1.\u003c/li\u003e\n\u003cli\u003eBorghese G, Raimondo D, Esposti DE, Aru CA, Raffone A, Orsini B, et al. Preoperative ureteral stenting in women with deep posterior endometriosis and ureteral involvement: Is it useful? International Journal of Gynecology \u0026amp; Obstetrics. 2022;158(1):179-86.\u003c/li\u003e\n\u003cli\u003eReinhart BM, Huntington RC, Blair JL, Heniford TB, Augenstein AV. Indocyanine Green. Surgical Innovation. 2016;23(2):166-75.\u003c/li\u003e\n\u003cli\u003eBoni L, David G, Mangano A, Dionigi G, Rausei S, Spampatti S, et al. Clinical applications of indocyanine green (ICG) enhanced fluorescence in laparoscopic surgery. Surgical Endoscopy. 2015;29(7):2046-55.\u003c/li\u003e\n\u003cli\u003eBuechi AC, Siegenthaler F, Sahli L, Papadia A, Saner MAF, Mohr S, et al. Real-World Data Assessing the Impact of Lymphovascular Space Invasion on the Diagnostic Performance of Sentinel Lymph Node Mapping in Endometrial Cancer. Cancers. 2023;16(1):67.\u003c/li\u003e\n\u003cli\u003eLee Z, Moore B, Giusto L, Eun DD. Use of indocyanine green during robot-assisted ureteral reconstructions. Eur Urol. 2015;67(2):291-8.\u003c/li\u003e\n\u003cli\u003eDelgadillo Chabolla LE, Alpuing Radilla LA, Koythong T, Sunkara S, Mendez Y, Wang Q, et al. Exploring the feasibility of indocyanine green fluorescence for intraoperative ureteral visualisation in robotic transvaginal natural orifice transluminal endoscopy surgery during endometriosis resection. Int J Med Robot. 2024;20(3):e2636.\u003c/li\u003e\n\u003cli\u003eCentini G, Colombi I, Cannoni A, Habib N, Giorgi M, Ginetti A, et al. Systematic use of intraureteral indocyanine green: a game changer in endometriosis surgery. A proof-of-concept study. Minim Invasive Ther Allied Technol. 2024;33(5):287-94.\u003c/li\u003e\n\u003cli\u003eMandovra P, Kalikar V, Patankar RV. Real-Time Visualization of Ureters Using Indocyanine Green During Laparoscopic Surgeries: Can We Make Surgery Safer? Surg Innov. 2019;26(4):464-8.\u003c/li\u003e\n\u003cli\u003eSong HC, Wu MH, Liu JX, Cao ZB, Du Y, Shi MJ, et al. Retrograde transurethral injection of indocyanine green better assists complete transperitoneal nephroureterectomy in a single-position. Transl Androl Urol. 2024;13(9):1868-77.\u003c/li\u003e\n\u003cli\u003eRogers P, Dourado J, Wignakumar A, Weiss B, Aeshbacher P, Garoufalia Z, et al. The role of ureteric indocyanine green fluorescence in colorectal surgery: a retrospective cohort study. Tech Coloproctol. 2024;28(1):83.\u003c/li\u003e\n\u003cli\u003eJafari DM, Wexner DS, Martz EJ, Mclemore CE, Margolin AD, Sherwinter AD, et al. Perfusion Assessment in Laparoscopic Left-Sided/Anterior Resection (PILLAR II): A Multi-Institutional Study. Journal of the American College of Surgeons. 2015;220(1):82-92e1.\u003c/li\u003e\n\u003cli\u003eGuerriero S, Condous G, Bosch DVT, Valentin L, Leone GPF, Schoubroeck VD, et al. Systematic approach to sonographic evaluation of the pelvis in women with suspected endometriosis, including terms, definitions and measurements: a consensus opinion from the International Deep Endometriosis Analysis (IDEA) group. Ultrasound in Obstetrics \u0026amp; Gynecology. 2016;48(3):318-32.\u003c/li\u003e\n\u003cli\u003eClavien AP, Barkun J, Oliveira DLM, Vauthey NJ, Dindo D, Schulick DR, et al. The Clavien-Dindo Classification of Surgical Complications. Annals of Surgery. 2009;250(2):187-96.\u003c/li\u003e\n\u003cli\u003ePark H, Farnam R. Novel Use of Indocyanine Green for Intraoperative, Real-time Localization of Ureter During Robot-Assisted Excision of Endometriosis. Journal of Minimally Invasive Gynecology. 2015;22(6):S69.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"archives-of-gynecology-and-obstetrics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"arch","sideBox":"Learn more about [Archives of Gynecology and Obstetrics](https://www.springer.com/journal/404)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/arch/default.aspx","title":"Archives of Gynecology and Obstetrics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Endometriosis, deep infiltrating, indocyanine green, ureteral visualisation","lastPublishedDoi":"10.21203/rs.3.rs-9510556/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9510556/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eObjective: To evaluate the feasibility and safety of intraureteral indocyanine green fluorescence for real-time ureter visualisation during laparoscopic surgery for deep infiltrating endometriosis.\u003cbr\u003e\nMethods: This prospective, single-centre cohort study was conducted at a tertiary referral centre for endometriosis. Premenopausal women with histologically confirmed or clinically highly suspected deep infiltrating endometriosis (DIE) who were scheduled for surgical treatment were eligible for inclusion.\u003c/p\u003e\n\u003cp\u003eAfter initial laparoscopic inspection, cystoscopy was performed, followed by retrograde intraureteral injection of indocyanine green (ICG). A dose of 25 mg ICG diluted in 5 mL sodium chloride solution was administered into each ureter. Near-infrared fluorescence imaging was subsequently used during laparoscopy to assess ureteral fluorescence and enable real-time visualization. Surgical treatment of DIE, including ureterolysis when required, was performed according to institutional standards. Duration of cystoscopy and ICG-injection, ureter visualization, time to fluorescence, and duration of fluorescence signal were prospectively recorded, along with necessity for ureterolysis as well as relevant patient and surgical characteristics.\u003c/p\u003e\n\u003cp\u003eResults: Fifty-one patients (mean age 36 years) were included. The mean duration of surgery was 217.3 ± 81.1 minutes. The mean duration of cystoscopy was 7.0 ± 5.0 minutes, and intraureteral ICG-injection required 4.3 ± 3.3 minutes. Bilateral ureteral fluorescence was achieved in 50 of 51 patients (98%). Visualisation was immediate in all cases and persisted throughout surgery. Ureterolysis was required in 45% of patients. No ureteral injuries or ICG-related complications occurred.\u003c/p\u003e\n\u003cp\u003eConclusion: This study confirms the feasibility of intraureteral indocyanine green marking as its primary endpoint. The lack of indocyanine green-, cystoscopy-, or catheterisation-related complications confirms its safety, and the minimal additional procedural time enables routine use while improving intraoperative orientation through real-time ureter visualisation.\u003c/p\u003e","manuscriptTitle":"Laparoscopic Visualisation of the Ureters Using Near-Infrared Fluorescence Imaging After Retrograde Indocyanine Green Injection in Deep Infiltrating Endometriosis: The LAVIC Trial","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-15 16:09:09","doi":"10.21203/rs.3.rs-9510556/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"25293965343736860022300901870276458427","date":"2026-05-08T12:36:56+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-05-06T12:29:48+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-29T22:06:08+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-29T14:50:56+00:00","index":"","fulltext":""},{"type":"submitted","content":"Archives of Gynecology and Obstetrics","date":"2026-04-23T21:32:50+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"archives-of-gynecology-and-obstetrics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"arch","sideBox":"Learn more about [Archives of Gynecology and Obstetrics](https://www.springer.com/journal/404)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/arch/default.aspx","title":"Archives of Gynecology and Obstetrics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"025f86a5-9fb2-493f-ac86-9e27697c412e","owner":[],"postedDate":"May 15th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"25293965343736860022300901870276458427","date":"2026-05-08T12:36:56+00:00","index":7,"fulltext":""},{"type":"reviewersInvited","content":"1","date":"2026-05-06T12:29:48+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-29T22:06:08+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-29T14:50:56+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-15T16:09:09+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-15 16:09:09","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9510556","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9510556","identity":"rs-9510556","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}