Table 4.

Estimated adjusted odds ratios (robotic vs. laparoscopic) for conversion to open surgery vs. operating surgeon’s level of previous laparoscopic and robotic experience

Effect	Surgeon’s laparoscopic experience level (no. of previous operations)	Surgeon’s robotic experience level (no. of previous operations)	Adjusted odds ratio (robotic vs. laparoscopic)	95% confidence interval for adjusted odds ratio
				Lower limit	Upper limit
Primary analysis model Robotic surgery (vs. laparoscopic)	–	–	0.614	0.311	1.211
Learning effects model Robotic surgery (vs. laparoscopic)	45	30	0.969	0.431	2.178
		50	0.559	0.264	1.185
		100	0.265	0.084	0.840
	91	30	0.968	0.432	2.172
		50	0.559	0.265	1.180
		100	0.265	0.084	0.836
	180	30	0.960	0.431	2.138
		50	0.554	0.267	1.151
		100	0.263	0.085	0.814