Lai CJ, Liu CM, Wu CY, Tsai FF, Tseng PH, Fan SZ. BMC Anesthesiol. 2017 Jan 6;17(1):3
Randomised controlled trial of 40 patients divided equally between i-gel and ETT groups. Leak fraction was the primary outcome, defined as leak volume divided by inspired tidal volume. In the LPT position, no difference was recorded in the leak fraction. In the i-gel group there was 'notably less' leakage in LPT position than in supine - this difference was not observed in the ETT group. Incidence of postoperative sore throat was significantly lower in the i-gel group.
Link to abstract.