Abstract: Two studies are included, which involved a total of 114 people with penetrating abdominal injuries. Both studies are at moderate risk of bias because the randomisation methods are not fully described, and the original study protocols are no longer available. The studies were undertaken in Finland between 1992 and 2002, by the same two researchers. In one study, 51 people were randomised to surgery or an observation protocol. None of the participants in the study died. Seven people had complications: 5 (18.5%) in the surgical group and 2 (8.3%) in the observation group; the difference was not statistically significant (P = 0.42; Fischer's exact). Among the 27 people who had surgery, 6 (22.2%) surgeries were negative laparotomies, and 15 (55.6%) were non-therapeutic. In the other study, 63 people were randomised to diagnostic laparoscopy (surgery) or an observation protocol. There were no deaths and no unnecessary surgeries in either group. Four people did not receive the intervention they were assigned. There was no difference in therapeutic operations between the two groups: 3 of 28 in the diagnostic laparoscopy group versus 1 of 31 in the observation protocol group (P = 0.337). Based on the findings of 2 studies involving a total of 114 people, there is no evidence to support the use of surgery over an observation protocol for people with penetrating abdominal trauma who have no signs of peritonitis and are stable.

Plain-language summary: The authors of this review sought to identify every study where people with an abdominal injury were randomised to surgery or observation. The authors searched a variety of medical databases but only identified 2 studies, involving 51 and 63 people respectively, both of which took place in Finland and were conducted by the same researchers. Both studies included people with penetrating abdominal injuries, from having been stabbed. The review authors considered both studies to be at moderate risk of bias, since only part of the randomisation process was described and the study protocols were not available to enable full assessment of overall quality. In one study (1992-1994) people received either an observation protocol or mandatory surgery. None of the people in the study died, and there was no difference in the number of people with medical complications between the study groups. One of the harms mentioned by the study authors was that surgery was performed on some people who did not actually need it. Unnecessary surgery can subject people to potential complications. In the other study (1997-2002) people received an observation protocol or diagnostic laparoscopy (minimal surgery). No one died in either group, and there were no differences between the groups in the number of surgeries needed. There were no unnecessary surgeries in either group. Based on the findings of these two small studies, there is no evidence to support the use of surgical management over an observation protocol for people with abdominal trauma showing no signs of bleeding or infection. The authors recommend that future randomised controlled studies clearly report the type of injury, number of damaged organs, extent of damage of internal organs, and complications in the people included.