The Utility of a Digital Virtual Template for Junior Surgeons in Pedicle Screw Placement in the Lumbar Spine

Table 1

Pedicle breaches per each level.

	Number of PS		Breach grade of DVTG PS				Breach grade of HFG PS
	DVTG	HFG	Grade 0	Grade 1	Grade 2	Grade 3	Grade 0	Grade 1	Grade 2	Grade 3
L1	5	5	2	1	0	0	3	0	0	0
L2	5	5	4	1	0	0	4	1	0	0
L3	7	7	6	1	0	0	5	2	0	0
L4	13	13	14	0	0	0	12	1	0	0
L5	14	14	14	1	0	0	14	1	0	0
S1	5	5	5	0	0	0	5	1	0	0
Total	49	49	45	4	0	0	43	6	0	0

PS: pedicle screw; DVTG: digital virtual templating group; HFG: hand-free group.
Grade 0: the whole screw is in pedicle; Grade 1: <2 mm and <1/2 diameter of the screw is out of pedicle; Grade 2: >2 and <4 mm or <1 screw diameter of the screw is out of pedicle; and Grade 3: >4 mm or the whole screw diameter is out of pedicle [14].