| BackgroundRectal cancer is one of the common cancers in China with a relatively high mortality rate,and low rectal cancer accounts for a high proportion of all rectal cancers.In recent years,with the deepening of scholars’ understanding of pelvic anatomy and the continuous improvement of surgical methods for low rectal cancer,the lateral structures of the rectum have attracted widespread attention due to their complexity and controversy.There is still a huge controversy over the existence of the middle rectal artery in the lateral ligaments of the rectum in terms of anatomy.In terms of surgery,lateral lymph node metastasis of rectal cancer usually follows the lateral ligament of the rectum.Although the incidence of lateral lymph node metastasis of rectal cancer is low and few hospitals routinely perform lateral lymph node dissection,Chinese scholars believe that lateral lymph node dissection should still be actively performed for patients with metastatic preoperative diagnosis of positive lateral lymph nodes.Due to the difficulty and high incidence of complications associated with this surgery,further exploration is needed to improve its safety and effectiveness.With the development of laparoscopic surgery,the use of laparoscopic ultrasound in clinical practice has gradually emerged.However,there have been no reports on the use of laparoscopic ultrasound in colorectal surgery.Given the high sensitivity of laparoscopic ultrasound in exploring lymph nodes,blood vessels,and solid tumors,we believe that the application of ultrasound in exploring lymph nodes and blood vessels in the lateral structures of the rectum is feasible.Purpose1.For patients undergoing lateral lymph node dissection for rectal cancer,explore whether intraoperative use of laparoscopic ultrasound can increase the number of lateral lymph nodes removed during surgery and reduce intraoperative complications2.Using laparoscopic ultrasound to investigate the incidence and common characteristics such as diameter and symmetry of the rectal artery in rectal cancer surgeryMethodsPart 1.Application of Intraoperative Laparoscopic Ultrasonography in Lateral Lymph Node Dissection for Low Rectal CancerA prospective cohort study was conducted on patients with low rectal cancer who underwent laparoscopic-assisted radical resection and lateral lymph node dissection at the affiliated hospital of XX University from January 2020 to January 2023.Inclusion criteria were as follows:(1)age between 18 and 75 years;(2)pathological confirmation of rectal adenocarcinoma by colonoscopic biopsy;(3)Eastern Cooperative Oncology Group(ECOG)performance status score of 0 or 1;(4)tumor lower margin located below the peritoneal reflection;(5)preoperative imaging diagnosis of stage II-III tumor;(6)preoperative magnetic resonance imaging showing a short-axis diameter of pelvic lymph nodes ≥5mm(regardless of whether neoadjuvant therapy was performed);(7)planned laparoscopic rectal cancer radical resection;and(8)strong surgical willingness and signed informed consent.All enrolled patients underwent standard laparoscopic rectal cancer radical resection and lateral lymph node dissection.Before performing lateral lymph node dissection,the operating surgeon has the discretion to decide whether to use laparoscopic ultrasound to explore the pelvic sidewall based on personal habits.Patients were divided into a laparoscopic ultrasonography group(LUS group)and a non-laparoscopic ultrasonography group(Non-LUS group)according to use laparoscopic ultrasound or not.The surgical time,intraoperative blood loss,total number of removed lateral lymph nodes,number of removed metastatic positive lateral lymph nodes,postoperative and intraoperative complications,and male sexual and urinary function scores were compared between the two groups.Part 2.A study on the incidence of the middle rectal artery during laparoscopic ultrasound in rectal surgeryThe study will use a cross-sectional study design and include all patients with low rectal cancer who are planned to undergo laparoscopic-assisted radical resection for rectal cancer in a certain main clinic of the Department of Colorectal Surgery at the affiliated hospital of XX University from January 2022 to January 2023.The inclusion criteria for the study are that the lower edge of the tumor is less than 6 cm from the margin and the preoperative imaging diagnosis indicates a tumor stage of T1-3.All patients underwent laparoscopic rectal cancer radical resection.The lateral rectal ligament is preserved when separating to the pelvic floor,and the lateral rectal ligament is explored using laparoscopic ultrasound,then the presence or absence and the general characteristics such as the diameter and number of the middle rectal artery are recorded.After the exploration is complete,based on the results of laparoscopic ultrasound exploration,the intraoperative dissection is performed to confirm whether the middle rectal artery can be dissected.ResultsPart 1.Application of Intraoperative Laparoscopic Ultrasonography in Lateral Lymph Node Dissection for Low Rectal CancerA total of 37 patients were included in the study,with 11 patients in the laparoscopic ultrasound exploration group(LUS group)and 26 patients in the non-laparoscopic ultrasound exploration group(Non-LUS group).There were no statistically significant differences in general data between the two groups(P>0.05).The intraoperative bleeding volume in the LUS group was significantly lower than that in the Non-LUS group(125ml[50-200] vs.200 ml [150-287.5];P=0.040).There were no significant differences between the two groups in terms of operative time,location of lateral lymph node dissection,surgical aspects,ostomy creation,and intraoperative complications(P>0.05).The total number of resected lateral lymph nodes in the LUS group was significantly higher than that in the Non-LUS group(5.27±3.10 vs.2.88±1.80;P=0.006),but there was no significant difference in the number of positive lateral lymph nodes removed between the two groups(P>0.05).In addition,there were no significant differences in postoperative pathological staging between the two groups(P>0.05).There were no significant differences in terms of recurrence,metastasis,mortality,and urinary and sexual function in male patients at 3months postoperatively between the two groups(P>0.05).Part 2.A study on the incidence of the middle rectal artery during laparoscopic ultrasound in rectal surgery.33 patients were included in the study,including 20 males(60.6%)and 13 females(39.4%),with 12 patients receiving neoadjuvant therapy(36.4%).The mean age of the patients was 58.7±10.1 years,and the mean distance of the tumor from the anal verge was4.2±1.1cm.The average operation time was 179.8±42.4 minutes,with intraoperative bleeding of 102.6±59.2ml.29 patients underwent Dixon surgery(87.9%)and 4 patients underwent Miles surgery(12.1%).In terms of pathological staging,there was 1 patient with p CR(3.0%),6 patients with stage I disease(18.2%),11 patients with stage II disease(33.3%),14 patients with stage III disease(42.5%),and 1 patient with stage IV disease(3.0%).Among the 33 patients,1 patient failed to separate the left rectal ligament and 2patients failed to separate the right rectal ligament.The overall incidence of middle rectal artery was 92.1% under laparoscopic ultrasound examination.The mean diameter of the left middle rectal artery under laparoscopic ultrasound examination was 1.54±0.40 mm,and that of the right was 1.77±0.31 mm.Among the patients examined by laparoscopic ultrasound,86.7% had middle rectal artery on both sides,3.3% had no middle rectal artery on both sides,and 10.0% had middle rectal artery on only one side.According to the results of laparoscopic ultrasonography,the proportion of the middle rectal artery in the rectum during anatomical dissection was 69.8%.Conclusions1.The use of laparoscopic ultrasound in lateral lymph node dissection for low rectal cancer can increase the total number of lymph nodes removed and improve the quality of lymph node dissection2.The use of laparoscopic ultrasound can distinguish the adjacent relationship between enlarged lymph nodes and surrounding large blood vessels,reduce intraoperative bleeding3.The middle rectal artery is a blood vessel that appears symmetrically and consistently below the peritoneal reflection through the lateral ligament of the rectum4.The diameter of the middle rectal artery is relatively small,mostly between 1-2mm,and is difficult to detect during surgery... |
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