Table 2.

Fluoroscopic ETs per treated level of the case groups

	ETapper single level (min)	ETlatper single level (min)	ETapper multi-level (min)	ETlatper multi-level (min)
All cases	1.6 (0.5–3.0)	2.2 (0.6–4.3)	1.1 (0.5–2.0)	1.7 (0.6–2.9)
Cases 1–44	1.6 (0.5–3.0)	2.3 (0.7–4.3)	1.1 (0.5–2.0)	1.8 (1.0–2.9)
Cases 45–60	1.6 (0.8–2.5)	2.0 (0.6–3.2)	1.0 (0.6–1.5)	1.5 (0.6–2.7)

Mean exposure time in the respective plane (ET_ap or ET_lat) in minutes of the entire collective (all), case group 1–44 and case group 45–60. Exposure times are broken down into minutes/level for single level cases and minutes per level for multi-level cases. Minimum and maximum values are respectively listed in brackets