Dissection of the inferior mesenteric vein versus of the inferior mesenteric artery for the genitourinary function after laparoscopic approach of rectal cancer surgery: a randomized controlled trial

Pallisera-Lloveras et al. BMC Urology (2019) 19:75 https://doi.org/10.1186/s12894-019-0501-5 STUDY PROTOCOL Open Access Dissection of the inferior mesenteric vein versus of the inferior mesenteric artery for the genitourinary function after laparoscopic approach of rectal cancer surgery: a randomized controlled trial Anna Pallisera-Lloveras1* , Paula Planelles-Soler2, Naim Hannaoui2, Laura Mora-López1, Jesús Muñoz-Rodriguez2, Sheila Serra-Pla1, Arturo Dominguez-Garcia2, Joan Prats-López2, Salvador Navarro-Soto1, Xavier Serra-Aracil1 and on behalf of Tauli-Colorectal Cancer Study Group Abstract Background: Total Mesorectal Excision (TME) is the standard surgical technique for the treatment of rectal cancer. However, rates of sexual dysfunction ofup to 50% have been described after TME, and rates of urinary dysfunction of up to 30%. Although other factors are involved, the main cause of postoperative genitourinary dysfunction is intraoperative injury to the pelvic autonomic nerves. The risk is particularly high in the inferior mesenteric artery (IMA). The aim of this study is to compare pre- and post-TME sexual dysfunction, depending on the surgical approach usedin the inferior mesenteric vessels: either directly on the IMA, or from the inferior mesenteric vein (IMV) to the IMA. Methods: Prospective, randomized,controlled study of patients with rectal adenocarcinoma with neoadjuvant chemoradiotherapy, who will be randomly assigned to one of two groups depending on the surgical approach to the inferior mesenteric vessels. The main variable is pre- and postoperative sexual dysfunction; secondary variables are visualization and preservation of the pelvic autonomic nerves, pre- and postoperative urinary dysfunction, and pre- and postoperative quality of life. The sample will comprise 90 patients, 45 per group. Discussion: The aim is to demonstrate that the dissection route from the IMV towards the IMA favors the preservation of the pelvic autonomic nerves and thus reducesrates of sexual dysfunction post-surgery. Trial registration: Ethical and Clinical Research Committee, Parc Taulí University Hospital: ID 017/315. ClinicalTrials.gov TAU-RECTALNERV-PRESERV-2018 (TRN: NCT03520088) (Date of registration 04/03/2018). Keywords: Genitourinary dysfunction, Injury to the pelvic autonomic nerves, Total Mesorectal excision, Rectal cancer * Correspondence: ; 1 Coloproctology Unit, General and Digestive Surgery Department, Parc Taulí University Hospital, Sabadell, UniversitatAutònoma de Barcelona, Parc Taulí s/n. 08208 Sabadell, Barcelona, Spain Full list of author information is available at the end of the article © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Pallisera-Lloveras et al. BMC Urology (2019) 19:75 Background Despite the advances in adjuvant and neoadjuvant chemotherapy (QT) and radiotherapy (RT) for colorectal cancer, surgery remains the only curative treatment [1]. Since its first description by Heald in 1982 [2, 3], Total Mesorectal Excision (TME) has been the standard surgical technique for the treatment of rectal cancer, and has brought about significant improvement in oncological results in terms of both survival and local recurrence [4]. However, the literature describes post-TME rates of urinary dysfunction (urinary incontinence, difficulty in voiding or neurogenic bladder) of up to 30% [5, 6]. The prevalence of sexual dysfunction is above 50%; in men, it includeserectile dysfunction and ejaculation problems, and in women, decreased vaginal lubrication, dyspareunia and difficulty reaching orgasm [5, 6]. For this reason, the study of functional results such as genitourinary function, fecal continence and quality of life in general is taking on increasing importance [1]. Although other factors may be responsible for postoperative genitourinary dysfunction, the main cause is intraoperative injury to the pelvic autonomic nerves [1, 6]. This inadvertent lesion usually occurs due to a lack of anatomical knowledge or due to poor visualization of the nerves [6]. Minimally invasive techniques such as laparoscopic colorectal surgery and robotic surgery have improved surgical technique and surgical visibility, that helps in recognizing the inferior hypogastric plexus [7]. Moreover, a thorough acquaintance with anatomical reference points and experience ofthe dissection during TME reduces the risk of injuring the autonomic nerves, and leaves the mesorectal fascia intact. Indeed, proficient TME technique helps to preserve the autonomic nerves, lowering the incidence of urinary dysfunction from 10 to 30% to 0–12% and sexual dysfunction from 40 to 60% to 10–35% [5, 6]. Table 1 shows the Page 2 of 10 genitourinary dysfunction after TME surgery, with the preservation of the pelvic autonomic nerves [8–10]. In rectal cancer surgery particular attention must be paid to certain areas, due to the risk of autonomic nerve damage [6]. Figure 1 depicts the surgical anatomy of the pelvic region and the key points where the risk of injury increases during surgery (Table 2) [5, 6, 11–14]. As described in the table, one of the regions with the highest risk of injury is the inferior mesenteric artery (IMA). Recently, Melani [15] described a new laparoscopic approach for the release of the splenic flexure, in which a dissection of the mesenteric vessels is performed from the inferior mesenteric vein (IMV) to the IMA. This route presents a dissection plane that follows the anatomical peritoneal sheets of the retroperitoneum and improves the visualization of the pelvic autonomic nerves from their origin. Compared with the standard approach to the inferior mesenteric vessels (i.e., directly on the IMA), we believe thatthe approach from the IMV to the IMA will improve nerve preservation and thus reduce the incidence of sexual and urinary dysfunction. Hypothesis and objectives Hypothesis The hypothesis is that the dissection route from the IMV to the IMA favors the preservation of the pelvic autonomic nerves, and thus reduces genitourinary dysfunction in patients after laparoscopic TME. Objectives The main objective is to determine the pre- and post-TME rates of sexual dysfunction in patients with rectal cancer randomly assigned to one of two nerve preservation techniques. In both groups, the secondary objectives are to assess: urinary dysfunction pre- and post-TME; the visualization Table 1 Genitourinary dysfunction after TME surger (...truncated)