Table 2.

Electrode measurements across all patients.

Patient number	Electrode number	Electrode location	Position	Electrode location confirmation	Radial target error	Depth error	Entry point radial error	Trajectory length
1	1	L HC	Supine	CT	2.7	0.0	0.5	92.6
2	1	R HC	Supine	CT	1.8	3.7	1.8	86.0
	2	L HC			2.4	3.3	0.4	88.9
3	1	L HC	Supine	CT	0.8	4.4	0.5	102.9
4	1	L HC	Supine	O-arm	3.0	5.8	0.1	97.4
	2	L para HC			2.7	−1.7	0.0	93.0
5	1	R HC	Supine	CT	0.4	−0.9	1.0	102.2
	2	L HC			2.1	−6.3	1.1	103.5
8	1	R HC	Supine	CT	1.0	−0.8	1.9	98.5
	2	L HC			2.0	−3.2	1.8	99.1
6	1	R HC	Prone	O-arm	0.7	−2	0.5	83.3
	2	L HC			0.9	−2.9	2.1	83.5
7	1	R HC	Prone	O-arm	0.3	5.3	0.2	85.7
	2	L HC			0.6	−1.2	0.9	87.7
9	1	R HC	Prone	O-arm	0.6	−1.8	0.5	89.8
	2	L HC			1.1	−7	0.0	92.9
10	1	R HC	Prone	O-arm	1.2	−0.4	0.8	83.1
	2	L HC			0.7	−1	1.5	81.9

All measurements in mm. Electrodes placed in the prone position had smaller radial target error compared to those placed in the supine position. HC, hippocampus.