Blunt versus bladed trocars in laparoscopic surgery: a systematic review and meta-analysis of randomized trials

Background Trocar-associated visceral injuries are rare but potentially fatal complications of laparoscopic access. More commonly, abdominal wall bleeding occurs, which usually requires hemostatic measures and prolongs operative time. Blunt-tipped trocars have been postulated to carry a lower risk of abdominal wall bleeding and intra-abdominal injuries. The aim of the present systematic review and meta-analysis was to comparatively evaluate the relative risks of abdominal wall bleeding, visceral injuries, and overall complications with the use of bladed and blunt-tipped laparoscopic trocars. Methods The databases of Medline, EMBASE, and the Cochrane Central Register of Randomized Trials were searched to identify randomized studies that compared trocar-associated complications with the use of blunt and bladed trocars. Primary outcome measure was the relative risk of abdominal wall trocar site bleeding, and secondary outcome measures included visceral injuries and overall complications. Outcome data were pooled and combined overall effect sizes were calculated using the fixed- or random-effects model. Results Eight eligible randomized trials were identified; they included 720 patients with a median Jadad score of 4. The incidence of abdominal wall bleeding for the blunt and the bladed trocar group was 3 and 9 %, respectively [odds ratio (OR) 0.42, 95 % confidence interval (CI) 0.21–0.88]. Trocar-associated morbidity rate, excluding bleeding events of the abdominal wall, was documented at 0.2 and 0.7 % of the blunt and the bladed trocar arm, respectively (OR 0.43, 95 % CI 0.06–2.97). The overall trocar-associated morbidity rate was 3 % in the blunt trocar group and 10 % in the bladed trocar group (OR 0.38, 95 % CI 0.19–0.77). Conclusions Reliable data support a lower relative risk of trocar site bleeding and overall complications with blunt laparoscopic cannulas than bladed trocars. Transition to blunt trocars for secondary cannulation of the abdominal wall is thus strongly recommended. Larger patient populations are required to estimate the relative risk of visceral injuries.