Role of dynamic computed tomography scans in patients with congenital craniovertebral junction malformations

Table 1 Nurick score

0	Root involvement. No spinal cord disease
1	Signs spinal cord disease without restriction in walking
2	Difficulty in walking without impact on employment
3	Difficulty in walking with impact on employment
4	Walk only with aid or walker
5	Bedridden or chair bound

Table 2 Patients main characteristics according to clinical status, follow-up and radiological parameters analyzed

No.	Gender	Nurick pre	Nurick post	Follow-up (mo)	Pathology	Clivus hypoplasia	Atlas assimilation	Treatment	Tonsillar herniation
1	38	4	2	38	BI + Chiari	Present	Absent	PFD + Duropls	14.95
2	35	3	2	30	BI + Chiari	Present	Absent	PFD + Duropls	15.19
3	15	2	1	21	BI + Chiari	Absent	Absent	PFD + Duropls + Tonsilec	9.4
4	29	2	1	30	Chiari I	Absent	Absent	PFD + Duropls	11.45
5	20	2	2	6	BI + Chiari	Present	Present	PFD + Duropls	11
6	40	2	1	14	BI + Chiari	Present	Present	PFD + Duropls	5
7	48	4	3	28	BI + Chiari	Absent	Present	PFD + Duropls + OCFix	7
8	56	5	3	8	BI + Chiari	Present	Present	PFD + Duropls + OCFix	N/A
9	52	1	1	5	Chiari I	Absent	Absent	PFD + Duropls	9
10	46	3	3	1	Chiari I	Absent	Absent	PFD + Duropls	7.44
M	37.9	2.8	1.9	1654					10.04

M: Mean; BI: Basilar invagination; PFD: Posterior fossa decompression; Duropls: Duroplasty; Tonsilec: Tonsillectomy; OCFix: Occipto-cervical fixation; N/A: Not available.

Table 3 Description of the main radiological characteristics obtained in flexion and in extension sagittal computed tomography scan

	Flexion position				Extension position
N	ADI	CCA	Facet dislocation	Chamberlain	ADI	CCA	Facet dislocation	Chamberlain
1	1.5	92°	Absent	+22.86	1.25	131°	Absent	+19.43
2	1.72	134°	Absent	+6.6	1.72	155°	Absent	+4.76
3	1.18	115°	Right side - 4 mm	+9.95	1.18	127°	Right side - 4 mm	+10.86
4	1.75	141°	Absent	0	1.75	155°	Absent	-3.7
5	0.5	120°	Absent	+20	0.6	125°	Absent	+19.3
6	3.27	130°	Absent	+12.28	3.12	140°	Absent	+12.11
7	5.67	130°	Left side - 2 mm	+8.26	2.94	161°	Right side - 3 mm	+4
8	1	108°	Right side - 4 mm	N/A	1	108°	Right side - 7 mm	N/A
9	0.36	146°	Absent	+3.97	0.36	176°	Absent	-5
10	0.7	138°	Left site 3.7 mm	+2.67	0.7	144°	Left side 3.7 mm	+2.32
M	1.76	125.4°		+9.62	1.46	142.2°		+7.11

M: Mean; ADI: Atlanto-dental interval; CCA: Clivus-canal angle; N/A: Not available.