Appendectomy as an Adjunct Procedure in Endometriosis Surgery

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.

Inclusion criteria

• Age 18-50 years
• Endometriosis diagnosis based on imaging or prior surgical findings
• Baseline pain above 3 on the Numerical Rating Scale (NRS)
• Undergoing surgical excision of endometriosis only, with at least one remaining ovary

Exclusion criteria

• Abnormal appearing appendix on imaging or intraoperatively
• No endometriosis seen at the time of surgery
• Previous appendectomy
• Menopausal