The Postoperative State of the Pelvis After Bowel Surgery for Deep Endometriosis: Still an Ultrasound Mystery

To the Editor: We read with great attention the article published by Martire et al. We congratulate the authors on investigating an important scientific area: the appearance of the pelvis on ultrasound imaging after surgery for endometriosis. The authors report that this is “the first study to describe the transvaginal ultrasound features of patients who were surgically treated by laparoscopic segmental rectosigmoid resection” for deep endometriosis (DE). We would like to point out that in 2020, our team published a research study entitled “Ultrasound Evaluation of Pouch of Douglas Obliteration and Rectal Deep Endometriosis in Women Who Have Had Previous Combined Colorectal and Gynaecological Laparoscopic Surgery for Rectal Endometriosis: A Pilot Study”. Compared to our study, this study found similarly high rates of pouch of Douglas (POD) obliteration after bowel surgery for DE (Martire et al, 58%; versus Alhayo et al, 36.4%). We reported a recurrence of bowel DE in 39.1% of participants, whereas Martire et al reported “residual or recurrent” posterior DE in 31.0%. We are glad to see that Martire et al acknowledge the possibility of residual disease, which remains a possibility (including in our study) even when preoperative ultrasound is used. In our study, we included participants who underwent rectal shaving, disk excision, or segmental resection. Hypothetically, rectal shaving or disk excision would be more prone to residual disease than segmental resection. All participants in the study by Martire et al underwent segmental resection, so we wonder whether this residual disease was posterior compartment DE other than rectal. We also wonder whether we are, in fact, observing residual/recurrent rectal DE rather than the aftereffects of surgery on the bowel (eg, fibrosis and anastomosis sites). The sample size in our study was small. Similarly, the sample size reported by Martire et al was small. We acknowledged the inability to adequately report the correlation between postoperative ultrasound findings and symptoms, although a very interesting concept. We are not convinced that there is an association between ultrasound findings and ongoing pain symptoms as suggested by Martire et al. No sample size calculation was performed in this study, and the retrospective design ingrained a high degree of bias. Only those who had an ultrasound examination performed within 6 to 12 months of their surgery were included. Patients who underwent segmental resection with substantial improvement in symptoms may not have returned for a postoperative ultrasound examination, and it is entirely possible that these patients had the same rate of residual/recurrent disease. The study that must be performed involves prospectively and routinely evaluating all patients after surgery for rectal endometriosis and POD obliteration to understand the state of the pelvis, regardless of patient well-being. There will always be a degree of uncertainty about whether noted findings are actual residual/recurrent disease or simply effects of surgery unless patients undergo a second-look laparoscopy. That said, because of the unfortunate chronic and complex nature of endometriosis, many patients do undergo subsequent surgeries in their lives. So, it may be possible to develop some understanding of noninvasive ultrasound findings in individuals who previously underwent advanced pelvic surgery, who may be undergoing reoperation.