How precise are oral splints for frameless stereotaxy in guided ear, nose, throat, and maxillofacial surgery: a cadaver study

European Radiology Experimental

Table 2 Assignment of 20 bone markers to three head regions (viscerocranium “V,” neurocranium “N,” and skull base “S”) and their distance to oral splints

Marker number	Localisation	Group	Distance from marker to splint’s median point (cm)
1	Hard palate	V	4.3
2	Subspinale processus	V	1.5
3	Right maxilla	V	4.6
4	Left zygomaticomaxillary suture	V	6.2
5	Right infraorbital rim	V	5.5
6	Right zygomatical anterior arch	V	6.6
7	Left lateral zygomatical arch	V	10.3
8	Right infraorbital zygomatic corpus	V/S	7.7
9	Right fronto zygomatico processus	N/S	10
10	Right orbital roof	N/S/V	7.7
11	Left lateral orbital roof	N/S/V	9.8
12	Glabella	N/S/V	7.5
13	Anterior frontal bone	N	14.4
14	Vortex	N	18.7
15	Lambda suture	N	22.5
16	Median occipital bone	N	24.5
17	Right parietal bone	N	21.2
18	Foramen magnum	N/S	9.3
19	Left parietal bone	H	15.2
20	Left mastoid	N/S	14.7

V Viscerocranium, N Neurocranium, S Skull base
The right column shows the distance from the splint’s centre point to the fiducial bone markers in cm. Points 8–12, 18, and 20 were assigned to several groups