Table 3.

Complication learning curve – Screw malposition and adjustment due to intraoperative CT.

	First 50 April 2008 – Mar 2010	Second 50 May 2010 – August 2011	Third 50 Sept 2011 – October 2012	Total
Screws adjusted due to CT	4/216 screws = 1.9%	3/209 screws = 1.4%	1/202 screws = 0.5%	8/627 screws = 1.3%
TOTAL adjusted trajectories + Screws (EMG + CT)	11/216 screws = 5.1%	9/209 screws = 4.3%	4/202 screws = 2.0%	24/627 screws = 3.8%

Note: Some adjusted screws were malpositioned on intraoperative CT, as well as EMG signal positive.