Our study shows ASBO surgery can be performed by laparoscopic approach with very good outcomes provided that the procedure can be completed without the need for conversion. Adequate preoperative selection of patients to avoid the need for conversion and the availability of a group of surgeons with advanced laparoscopic skills is crucial to achieve this.
Our team carried out a preliminary study that demonstrated the feasibility and safety of the laparoscopic approach in ASBO, as well as better outcomes when compared with a group of patients undergoing open surgery(32). However, in this study, a selection bias of patients was obvious, which made it difficult to interpret the results. We therefore undertook the present study with a sufficient number of patients, to allow a propensity-scores matching analysis to identify variables that could favour the laparoscopic approach.
In the overall analysis of the current series, as in the preliminary study(32), the laparoscopic approach significantly reduced morbidity and mortality. However, the heterogeneous distribution of some pre-operative variables between the laparoscopic and open surgery groups shows that the positive impact of the laparoscopic approach on postoperative complications could be overestimated due to a selection bias. This limitation is also detected in other published studies(7, 10, 11, 23).
However, unlike most published series (16, 24, 27, 33), the results of our intention-to-treat matching analysis were similar to those published both in the randomized controlled trial(28) and in the propensity-score matching study of Hackenberg et al.(34) in which no reduction in morbidity after the laparoscopic approach has been demonstrated. This confirms that in general, surgeons select patients with certain characteristics for the laparoscopic approach(23, 27, 33).
The conversion rate in the literature varies from 24–51%(11, 29, 34, 35). In our study, this figure represented a significant subgroup in the laparoscopy group patients (36.7%). To clearly define the role of the laparoscopic approach, a second propensity-score matching analysis was performed excluding converted patients, In this subanalysis, it is clear that the laparoscopic approach presents significantly lower morbidity, earlier onset of oral intake and a shorter hospital stay. That is, conversion plays an important role within the laparoscopic approach. In the literature there are differences in the way that the conversion was analysed. Among the studies that maintain these patients according to intention-to-treat (in the laparoscopic approach group), Sallinen et al.(28) and Hackenberg et al.(34) described no differences in terms of morbidity; Mancini et al.(16) reported fewer complications and Behman et al.(23) less serious complications in the laparoscopy group. Patel et al.(24) and Kelly et al.(33) did not describe how converted patients were analysed, but the former showed less morbidity and Kelly et al. only when analysing serious complications in the laparoscopic group. On the contrary, Yao et al.(27), included converted patients in the open surgery group and in this context post-operative morbidity was significantly lower in the laparoscopic group.
Therefore, with the results currently available better results with the laparoscopic approach are consistent only in patients in whom conversion can be avoided(16, 22, 29). The following factors play a relevant role in the need for conversion: previous median laparotomy, the characterization of a simple adhesion as the cause of occlusion, the existence of free fluid or intestinal distension > 4 cm in the computed tomography. In this setting open surgery should be the initial approach. When considering the laparoscopic approach, some technical aspects of laparoscopic such as avoiding the Veress needle, the careful manipulation of the dilated bowel loops, not using electrocoagulation or limiting adhesiolysis should be taken into account(36).
The present study has obvious limitations. This is a retrospective study, in which selection biases were also detected since the distribution of the pre-operative variables favours the results of the laparoscopic group. However, due to the difficulties in conducting a randomized controlled trial, as demonstrated by the fact that only one has been published, we consider that the propensity-score matching analysis is valid for reducing bias and has even been shown to be more accurate than multivariate analyses(37–39). On the other hand, to our knowledge, our study with 333 patients who underwent ASBO is the largest single-centre series published to date.