An interventional study of Appendectomy and Standard of Care (SOC) in Endometriosis, sponsored by Mount Sinai Hospital, Canada. Not yet recruiting. Open to female participants aged 18 Years to 50 Years. Per ClinicalTrials.gov, last updated 2026-09-16.
Sponsored by Mount Sinai Hospital, Canada · Not applicable, Interventional, and Treatment
This study addresses a common but unresolved clinical decision in endometriosis surgery: whether to perform an adjunct appendectomy. Currently, this decision is often based on individual surgeon judgement or institutional practice rather than robust evidence.
This randomized controlled study aims to determine if removing a normal appearing appendix at the time of endometriosis surgery impacts post-operative recurrence of pelvic pain and endometriotic lesions at 12 months. Secondary outcomes include pathology of the appendix and complication rate of the procedure.
Participants will be randomized to appendectomy or no appendectomy at the time of their planned endometriosis surgery. The study also includes an observational cohort that participants may opt to join if they do not wish to be randomized.
Data are expected to guide surgical decision-making and contribute to the development of standardized surgical guidelines.
Endometriosis is a chronic inflammatory disease characterized by the growth of endometrial-like tissue outside the uterine cavity, affecting approximately 1 in 10 women and those assigned female at birth during reproductive years. Surgical excision is a cornerstone of endometriosis disease management, particularly in patients with refractory pain, advanced disease, infertility, bowel or urinary tract involvement, or diagnostic uncertainty. However, outcomes are highly variable due to significant variability in surgical approach, underscoring the need for high quality, prospective evidence to optimize surgical intervention.
Appendiceal involvement presents such an opportunity for optimization, which is estimated to impact anywhere from 10-50% of patients in this population. Currently, only appendices that are visually abnormal at the time of surgery are removed. Existing literature, limited to retrospective data, suggests that the addition of appendectomy at the time of endometriosis surgery decreases the risk of postoperative pain and disease recurrence in patients who have received surgical management, regardless of the visual appearance of the appendix.
Notably, visual assessment of the appendix and confirmation of histopathologic appendiceal involvement are not found to be well-correlated.
At this time, there is a lack of quality prospective data to support implementation of adjunct appendectomy into surgical practice. This study aims to bridge this gap by providing the evidence needed to standardize surgical decision-making.
This randomized controlled study will enroll eligible participants between the ages of 18-50 (pre-menopausal), who will undergo laparoscopic or robotic-assisted excision of endometriosis performed by the Minimally Invasive Surgery (MIS) team at Mount Sinai Hospital in Toronto, ON. If the appendix appears normal intraoperatively, the surgeon will proceed with randomized allocation to either appendectomy or no appendectomy. Participants will remain blinded through follow-up, including validated ENDOPAIN-4D questionnaires administered at 6 and 12 months post-operatively and an endometriosis mapping ultrasound at 12 months post-op.
Additional outcomes will assess whether the risk of intra- and post-surgical complications increase with the addition of an appendectomy compared to laparoscopy alone. Data will also be used to evaluate the prevalence of various appendiceal pathologies, including endometriosis- and non-endometriosis-related.
If a participant is unwilling to be randomized but still wishes to participate, they will be invited to join the observational cohort. Participants in this arm will be given the option of whether or not the appendix should be removed during surgery, should it appear normal, aligning with current standard of care. Participants in this arm will undergo all follow-up milestones in an unblinded manner.
The results of this study will be submitted for publication and for presentation at relevant conferences.
920 studies on the registry are indexed under Endometriosis; 266 are open to participants now.
This study's planned enrollment of 240 is above the median of 67 across 540 interventional studies indexed under Endometriosis.
Browse Endometriosis studies →Mount Sinai Hospital, Canada is the lead sponsor of 158 studies on the registry; 32 are open to participants now.
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Exclusion criteria:
Participants randomized to have their appendix removed
Procedure: Appendectomy
Participants randomized to not have their appendix removed
Procedure: Standard of Care (SOC)
Participants will choose whether or not to have their appendix removed during surgery if it appears normal
Removal of the appendix at the time of endometriosis surgery
If the appendix appears normal during surgery it will not be removed
Change in pelvic pain severity
Change from baseline to 1 year in post-operative pain severity as measured by the ENDOPAIN-4D questionnaire (lower score = less pain)
Time frame: 1 year
Rate of endometriosis lesion recurrence
Rates of recurrence of endometriosis lesions based on 12-month endometriosis mapping ultrasound
Time frame: 1 year
Change in pelvic pain severity
Change from baseline to 6 months in post-operative pain severity as measured by the ENDOPAIN-4D questionnaire (lower score = less pain)
Time frame: 6 months
Change in pelvic pain severity
Change from baseline to 6 months in post-operative pain severity as measured by the Numerical Rating Scale (NRS; lower score = less pain)
Time frame: 6 months
Change in pelvic pain severity
Change from baseline to 1 year in post-operative pain severity as measured by the Numerical Rating Scale (NRS; lower score = less pain)
Time frame: 1 year
Postoperative complications
Postoperative analgesia use, sleep disturbances, and lifestyle impact at 30 days, reported by participant
Time frame: 30 days
Rate of positive appendiceal pathology
Pathology findings from appendix analysis
Time frame: 30 days
Types of appendiceal pathology
Types of endometriosis and non-endometriosis appendiceal pathology identified via histopathological analysis of removed appendices
Time frame: 30 days
Operative time
Duration of surgery
Time frame: During surgery
Postoperative analgesia use
Frequency of analgesic use post-surgery to manage pain
Time frame: 1 year
Percentage of eligible participants willing to be randomized
Of those who met study criteria, what percentage were willing to be randomized
Time frame: 1 year
No study locations are listed for this record.
Plan to share: No
No publications or documents are linked to this record.
This study is not yet recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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