This retrospective study aims to compare the surgical and pregnancy outcomes of disc and segmental resection for rectal DIE through a single-center retrospective analysis, to summarize clinical experience, and to explore the possible factor of the differences. The results would provide preliminary clinical basis for the treatment and selection of surgical methods for patients with rectal DIE, and also provide a research basis for the prospective clinical studies.

1. Research objectives This study aims to compare the surgical and pregnancy outcomes of disc and segmental resection for rectal DIE through a single-center retrospective analysis, to summarize clinical experience, to explore the possible factor of the differences and to followed up on the fertility outcomes of those who desire for pregnancy. The results would provide preliminary clinical basis for the treatment and selection of surgical methods for patients with rectal DIE, and also provide a research basis for the prospective clinical studies.
2. Innovation points In this retrospective study, innovation points are to compare the disease relief, perioperative complications and recurrence of two different surgical methods, disc resection and segmental resection, for rectal DIE involving the rectal mucosa and submucosa, and summarize past clinical experience. In order to provide preliminary clinical basis for the treatment and selection of surgical methods for patients with rectal DIE.
3. Research the main content This project intends to conduct a retrospectively observational study to collect the clinical data of patients with rectal DIE who underwent disc resection and segmental resection in a single center, to analyze perioperative complications, and to follow up the patients' symptom relief and recurrence. For those who desire for fertility, follow up their fertility status and pregnancy outcomes. By summarizing past clinical experience and exploring the possible influencing factors of the differences, we hope to provide preliminary clinical basis for the treatment and selection of surgical methods for patients with rectal DIE.
4. Key research methods and technologies:

Research methods: Single-center retrospective study

1. Case collection: Collect patients who were hospitalized in the Obstetrics and Gynecology Hospital of Fudan University in Shanghai from 2018 to 2023 and received surgical treatment for rectal endometriosis.

   Inclusion criteria: Patients who underwent surgery for endometriosis and were found to have endometriosis involving the full thickness of the rectum reaching the mucosa or submucosa during preoperative evaluation or intraoperative exploration, and who were diagnosed pathologically.

   Exclusion criteria: patients who have previously undergone surgical treatment of rectal endometriosis; patients with insufficient preoperative evaluation (lack of pelvic imaging evaluation or colonoscopy evaluation) and surgical removal of lesions; postoperative pathology shows rectal mucosa or The submucosa is not involved; patients with malignant tumors.

2. Case information collection: patient age, body mass index, menstrual status (menstrual period, cycle, menstrual volume), reproductive history, pain symptoms and extent (dysmenorrhea, dyspareunia), intestinal symptoms (constipation, diarrhea, anal incontinence and blood in the stool) , history of infertility, polycystic ovary syndrome, abdominal surgery history (number of surgeries and endometriosis-related surgeries), imaging evaluation (ultrasound and magnetic resonance evaluation results: adenomyosis, ovarian uterus Endometriosis cysts, organs involved in deep endometriosis, location, size, number, depth of rectal lesions and circumference of the intestinal tube involved), colonoscopy evaluation results, preoperative hormone treatment status and time (GnRHa , oral short-acting contraceptives, Mirena, dienogest, progesterone, etc.), tumor markers (CA125, CA199, CEA, etc.), AMH and preoperative hemoglobin, surgical methods (open, traditional laparoscopy, single hole laparoscopy), surgical method of rectal lesion resection (butterfly resection and segmental resection), anastomosis method (suture, stapler), distance from the lesion to the anus, size of the resected lesion (diameter, depth and circumference) , surgical content (hysterectomy, ovarian resection, and other endometriosis surgeries), operation time and amount of bleeding.

3. Surgical outcomes: decrease in hemoglobin, postoperative fever (whether ≥38°C), postoperative infection (pathogens confirmed by culture), perioperative blood transfusion treatment, postoperative complications (rectovaginal fistula, anastomotic fistula, Pelvic hematoma, urinary retention, organ damage, bleeding and multiple surgeries), postoperative hospitalization time, pathology (diameter, depth and circumference), postoperative auxiliary medication regimen and time (GnRHa, oral short-acting contraceptive pills , Mirena, dienogest, progesterone, etc.).

4. Pregnancy-related: whether there is a desire to get pregnant; the time to prepare for pregnancy after surgery; whether there are male infertility factors; pregnancy outcomes (pregnancy interval, natural conception rate, assisted reproduction pregnancy rate, miscarriage rate, pregnancy rate).

5. Recurrence: symptom assessment (pain level using VAS score and intestinal function recovery: frequency of defecation, stool shape, defecation pain, defecation effort) and imaging recurrence (magnetic resonance imaging shows lesions in the rectum).

6. Follow-up method: Obtain preliminary results through outpatient electronic medical records; telephone follow-up for patient symptom assessment.

7. Data analysis: Use SPSS software for data analysis. In descriptive statistics, categorical variables are expressed as numbers (percentages), and continuous variables are expressed as mean ± standard deviation. The t test was used to compare continuous variables between groups with normal distribution; the Mann-Whitney U test was used to compare continuous variables between groups with skewed distribution; the chi-square test was used to compare categorical variables between groups. The K-M curve plots postoperative recurrence and postoperative pregnancy. p<0.05 is considered to be statistically significant.

Inclusion Criteria:

• Patients who underwent surgery of disc and segmental resection followed by anastomosis for endometriosis
• Endometriosis involving the full thickness of the rectum reaching the mucosa or submucosa during preoperative evaluation or intraoperative exploration, and who were diagnosed pathologically.

Exclusion Criteria:

• Patients who have previously undergone surgical treatment of rectal endometriosis
• Patients with insufficient preoperative evaluation (lack of pelvic imaging evaluation or colonoscopy evaluation) and surgical removal of lesions;
• Postoperative pathology shows rectal mucosa or The submucosa is not involved; patients with malignant tumors.

Patient age, body mass index, menstrual status (menstrual period, cycle, menstrual volume), reproductive history, pain symptoms and extent (dysmenorrhea, dyspareunia), intestinal symptoms (constipation, diarrhea, anal incontinence and blood in the stool) , history of infertility, polycystic ovary syndrome, abdominal surgery history (number of surgeries and endometriosis-related surgeries), imaging evaluation (ultrasound and magnetic resonance evaluation results: adenomyosis, ovarian uterus Endometriosis cysts, organs involved in deep endometriosis, location, size, number, depth of rectal lesions and circumference of the intestinal tube involved), colonoscopy evaluation results