Our study found that the conversion rate in surgery for ileocolonic Crohn’s disease from minimally invasive (MIS) to open surgery is 10.7%. Although conversion rates in patients with Crohn’s disease vary greatly, our findings are in agreement with previous data reported in the literature.
Milsom et al. and Maartese et al., the only two randomised clinical trials analysing laparoscopic vs open surgery for Crohn’s disease, reported conversion rates of 6.0% and 10.0%, respectively [11], [17], while in a meta-analysis of 2007, Tan et al. observed a pooled conversion rate of 11.2% (4.8% – 29.2%) [18].
Higher rates have been reported for complex (18.6%) and recurrent (28%) CD [19], [20]. Indeed, in our pool, converted patients were twice as likely to have penetrating disease or require associated procedures during surgery. However, our regression analysis did not establish a correlation between previous surgery and likelihood of conversion. Contrary to conventional perspectives, laparoscopy consistently preserves its benefits, including reduced post-operative complications and shorter hospital stays, even within the challenging contexts of complex and recurrent CD [19], [20]. Moreover, MIS is associated with fewer adhesions, a great advantage for young Crohn’s patients who are likely to require multi-quadrant reoperations throughout their lives [21], [22].
We found that the main risk factors for conversion are age, urgent or emergent case, ileocolonic location of the disease, perforation and associated procedures being performed during surgery.
These findings are consistent with results from previous studies [10], [23], [24]. However, the latest WSES-AAST guidelines support the use of laparoscopy in emergency as it reduces the length of stay and has fewer complications. Indications for emergent laparoscopic surgery include intestinal obstruction, bleeding, free perforation and purulent/faecal peritonitis and Crohn’s colitis as long as the patient is hemodynamically stable [25]. Moreover, according to the ECCO Guidelines, laparoscopy should be proposed as first-line treatment when expert laparoscopic surgeon is available.
These considerations lead to the critical aspect of the learning curve for minimally invasive surgery. Mege et al. and Maggiori et al. reported on their 10 + years of experience with laparoscopy for IBD [26], [27]. While a decrease in conversion rates is often expected with the surgeon’s progressive learning curve, as reported by Maggiori et al. (from 18% ± 12 to 6% ± 5), greater complexity of selected cases or more aggressive disease pattern could explain Mege’s et al. increasing rates (from 9–23%). Nevertheless, neither experienced worse outcomes with laparoscopy versus open surgery [26], [27].
Several recent studies have also investigated the role of robotic surgery in the treatment of CD.
Although not statistically relevant, we observed no conversions in our limited robotic cohort. A 2018 systematic review reported a conversion rate of 7.3%, while a more recent one from 2022 reported conversion rates of 1.7% and 3.4% for total/subtotal colectomy and total proctocolectomy/completion colectomy, respectively [28], [29]. In 2021, Flynn et al. observed similar learning curves for robotic and laparoscopic surgery as well as lower conversion rates, especially during the early phases of learning [30]. Gunnells et al. suggest that robotic surgery is safe and feasible in Crohn’s patients and that it could overcome some of the technical difficulties of IBD surgery [31].
Our study has several limitations that warrant consideration. First, the recruitment of participating centres relied on an open call and newsletter by the SICCR, potentially excluding hospitals with limited involvement in the society’s activities. This could introduce a selection bias. Second, the retrospective design of the study and reliance on self-reported information pose inherent risks of information and recall bias. Additionally, a critical limitation lies in the absence of detailed information on the time of conversion and a standardised definition for conversion, limiting our ability to assess the impact of early versus late conversions on outcomes. Early conversions are generally expected to have fewer complications than those occurring after prolonged operation times. Lastly, the study lacks information on long-term outcomes and standardised PROMs, which could provide valuable insights into the patients’ perspectives on their surgical experiences and long-term quality of life.