Computed tomography-derived assessment of respiratory impairment in thoracic scoliosis: Comparison between idiopathic and non-idiopathic etiologies

Table 1 Comparison of clinical characteristics, spinal thoracic deformity parameters, and computed tomography-derived respiratory function parameters between idiopathic and non-idiopathic scoliosis

		Total (n = 53)	Idiopathic (n = 25)	Non-idiopathic (n = 28)	P value
Age (year)		15 (11-30)	15 (12-30)	15 (11-26)	> 0.99
Gender (male)		19 (35.8)	2 (10.5)	17 (89.5)	< 0.001
Height (cm)		152 (143, 159)	157 (154, 162)	144 (139, 149)	< 0.001
Cobb angle (°)		65 (46, 84)	47 (38, 65)	82 (59, 99)	< 0.001
AVT (mm)		46 (31, 77)	38 (24, 47)	75 (43, 92)	< 0.001
AVB-R		0.66 (0.35, 0.81)	0.67 (0.51, 0.78)	0.61 (0.22, 1.5)	0.36
RAml (°)		38 (26, 59)	30 (21, 39)	55 (28, 74)	< 0.001
RAsag (°)		20 (12, 38)	14 (11, 22)	36 (17, 45)	< 0.001
TLC%		54 (37, 68)	64 (59, 75)	39 (29, 53)	< 0.001
Lung volume (mL)	Total	2307 (1390, 2982)	2865 (2548, 3421)	1471 (860, 2178)	< 0.001
	Right	1241 (785, 1582)	1560 (1376, 1888)	823 (437, 1145)	< 0.001
	Right upper	421 (257, 529)	496 (428, 603)	262 (168, 381)	< 0.001
	Right middle	192 (147, 274)	243 (192, 311)	155 (104, 210)	< 0.001
	Right lower	597 (318, 799)	778 (682, 1002)	359 (168, 557)	< 0.001
	Left	1121 (589, 1369)	1293 (1142, 1542)	658 (408, 1058)	< 0.001
	Left upper	564 (315, 726)	714 (591, 815)	356 (222, 539)	< 0.001
	Left lower	504 (259, 648)	630 (512, 790)	281 (222, 539)	< 0.001
Tracheal bifurcation	Min diameter (mm)	11.9 (10.2, 13.2)	12.2 (10.9, 13.7)	11.4 (9.5, 13.1)	0.15
	Max diameter (mm)	17.4 (15.2, 19.7)	18.5 (16.9, 19.9)	15.8 (13.7, 18.5)	0.01
	Area (mm2)	178 (139, 211)	190 (160, 213)	153 (118, 190)	0.03
Narrowest tracheal segment	Min diameter (mm)	11.9 (9.5, 12.8)	12.1 (11.8, 13.1)	9.9 (6.3, 12.4)	0.001
	Max diameter (mm)	13.8 (12.5, 15.6)	14.1 (13.4, 15.6)	13.3 (11.7, 15.5)	0.18
	Area (mm2)	136 (93, 164)	140 (128, 166)	107 (64, 161)	0.04
Narrowest left bronchus	Min diameter (mm)	5.5 (4.4, 7.1)	6.3 (5.1, 7.3)	5.3 (4.1, 6.9)	0.08
	Max diameter (mm)	7.5 (5.9, 9.9)	8.6 (6.9, 10.3)	7.2 (5.3, 8.9)	0.054
	Area (mm2)	36 (22, 61)	45 (30, 64)	32 (17, 48)	0.06
Narrowest right bronchus	Min diameter (mm)	8.9 (7.2, 10.5)	9.7 (7.8, 11.0)	7.9 (7.1, 10.4)	0.09
	Max diameter (mm)	11.8 (9.2, 14.4)	13.1 (10.2, 15.3)	10.9 (8.9, 13.4)	0.051
	Area (mm2)	89 (57, 124)	97 (71, 142)	78 (56, 111)	0.04
Right-to-left bronchial length ratio		0.84 (0.78, 0.85)	0.84 (0.80, 0.86)	0.83 (0.77, 0.85)	0.36
Longitudinal analysis cohort (n)		50	24	26
Number of instrumented thoracic vertebrae		9 (4-11)	9 (8, 11)	9 (8, 10)	0.41
Number of instrumented vertebrae		13 (5-16)	12 (11, 13)	14.5 (12, 15)	0.001
Follow-up duration (months)		12 (6-12)	12 (10-12)	12 (6-12)	0.05

Data were shown as n (%) or mean ± SD or median (range). AVT: Apical vertebral translation; AVB-R: Apical vertebral body-rib ratio; RAml: Rotation relative to anterior midline; RAsag: Rotation relative to sagittal plane; TLC%: Predicted total lung capacity percentage.

Table 2 Spearman’s rank correlations between spinal thoracic deformity parameters and computed tomography-derived respiratory function parameters in patients with idiopathic scoliosis

		Cobb angle		AVT		AVB-R		RAml		RAsag
		ρ	P value	ρ	P value	ρ	P value	ρ	P value	ρ	P value
TLC%		0.069	0.74	-0.28	0.16	0.24	0.24	-0.37	0.06	-0.32	0.11
Lung volume	Total	0.12	0.54	-0.21	0.30	0.22	0.28	-0.42	0.03	-0.40	0.04
	Right	0.11	0.60	-0.30	0.13	0.34	0.09	-0.53	0.005	-0.57	0.002
	Right upper	0.21	0.30	-0.18	0.38	0.18	0.38	-0.39	0.04	-0.48	0.01
	Right middle	0.006	0.97	-0.25	0.21	0.35	0.07	-0.35	0.07	-0.28	0.16
	Right lower	0.12	0.56	-0.30	0.13	0.35	0.08	-0.54	0.004	-0.59	0.001
	Left	0.10	0.61	-0.08	0.69	0.053	0.80	-0.28	0.17	-0.20	0.31
	Left upper	0.24	0.22	-0.12	0.55	0.11	0.59	-0.30	0.14	-0.33	0.09
	Left lower	-0.088	0.67	-0.15	0.46	0.16	0.42	-0.31	0.13	-0.16	0.42
Tracheal bifurcation	Min diameter	0.29	0.15	-0.23	0.91	0.19	0.34	-0.22	0.28	-0.29	0.15
	Max diameter	-0.15	0.46	-0.25	0.22	0.24	0.23	-0.23	0.26	-0.15	0.45
	Area	0.042	0.84	-0.15	0.47	0.31	0.12	-0.31	0.12	-0.26	0.20
Narrowest tracheal segment	Min diameter	-0.21	0.30	-0.42	0.03	0.56	0.003	-0.56	0.003	-0.45	0.02
	Max diameter	0.063	0.76	-0.13	0.52	0.35	0.08	-0.37	0.06	-0.36	0.07
	Area	-0.11	0.57	-0.28	0.17	0.47	0.01	-0.51	0.008	-0.43	0.03
Narrowest left bronchus	Min diameter	-0.065	0.75	-0.13	0.53	0.22	0.27	-0.24	0.24	-0.15	0.47
	Max diameter	-0.15	0.44	-0.23	0.25	0.31	0.12	-0.36	0.07	-0.22	0.27
	Area	-0.091	0.66	-0.18	0.37	0.27	0.18	-0.30	0.13	-0.19	0.34
Narrowest right bronchus	Min diameter	0.053	0.77	-0.097	0.64	0.14	0.49	-0.10	0.62	0.008	0.96
	Max diameter	0.066	0.75	-0.11	0.57	0.24	0.23	-0.21	0.31	-0.13	0.50
	Area	0.011	0.95	-0.22	0.28	0.30	0.13	-0.28	0.16	-0.17	0.39
Right-to-left bronchial length ratio		0.40	0.043	0.42	0.03	-0.40	0.04	0.28	0.16	0.11	0.59

AVT: Apical vertebral translation; AVB-R: Apical vertebral body-rib ratio; RAml: Rotation relative to anterior midline; RAsag: Rotation relative to sagittal plane; TLC%: Predicted total lung capacity percentage.

Table 3 Spearman’s rank correlations between spinal thoracic deformity parameters and computed tomography-derived respiratory function parameters in patients with non-idiopathic scoliosis

		Cobb angle		AVT		AVB-R		RAml		RAsag
		ρ	P value	ρ	P value	ρ	P value	ρ	P value	ρ	P value
TLC%		-0.52	0.004	-0.42	0.02	0.52	0.004	-0.50	0.005	-0.50	0.005
Lung volume	Total	-0.55	0.002	-0.43	0.02	0.50	0.005	-0.52	0.003	-0.48	0.008
	Right	-0.48	0.009	-0.37	0.04	0.48	0.008	-0.46	0.01	-0.45	0.01
	Right upper	-0.50	0.005	-0.35	0.06	0.53	0.003	-0.43	0.02	-0.44	0.01
	Right middle	-0.26	0.17	-0.30	0.11	0.40	0.03	-0.41	0.02	-0.45	0.01
	Right lower	-0.42	0.02	-0.30	0.11	0.39	0.03	-0.38	0.04	-0.36	0.06
	Left	-0.62	< 0.001	-0.45	0.01	0.48	0.008	-0.54	0.002	-0.48	0.009
	Left upper	-0.56	0.001	-0.48	0.009	0.50	0.006	-0.54	0.002	-0.47	0.01
	Left lower	-0.62	< 0.001	-0.44	0.01	0.38	0.04	-0.55	0.002	-0.50	0.006
Tracheal bifurcation	Min diameter	-0.41	0.02	-0.35	0.06	0.23	0.23	-0.27	0.16	-0.21	0.26
	Max diameter	-0.53	0.003	-0.36	0.05	0.38	0.04	-0.42	0.02	-0.30	0.11
	Area	-0.52	0.004	-0.38	0.04	0.31	0.09	-0.36	0.054	-0.25	0.19
The narrowest tracheal segment	Min diameter	-0.29	0.12	-0.40	0.03	0.32	0.09	-0.38	0.04	-0.30	0.11
	Max diameter	-0.32	0.09	-0.37	0.04	0.37	0.048	-0.36	0.06	-0.24	0.20
	Area	-0.33	0.08	-0.39	0.03	0.45	0.01	-0.41	0.02	-0.32	0.08
The narrowest left bronchus	Min diameter	-0.39	0.03	-0.40	0.03	0.24	0.21	-0.37	0.049	-0.33	0.07
	Max diameter	-0.36	0.054	-0.36	0.06	0.24	0.21	-0.31	0.10	-0.27	0.15
	Area	-0.37	0.050	-0.38	0.04	0.18	0.33	-0.35	0.06	-0.33	0.08
The narrowest right bronchus	Min diameter	-0.42	0.02	-0.38	0.04	0.078	0.69	-0.31	0.10	-0.28	0.13
	Max diameter	-0.41	0.02	-0.35	0.06	0.051	0.79	-0.31	0.10	-0.23	0.22
	Area	-0.42	0.02	-0.38	0.04	0.073	0.70	-0.32	0.09	-0.25	0.18
Right-to-left bronchial length ratio		0.27	0.15	0.26	0.17	-0.29	0.12	0.43	0.02	0.47	0.01

AVT: Apical vertebral translation; AVB-R: Apical vertebral body-rib ratio; RAml: Rotation relative to anterior midline; RAsag: Rotation relative to sagittal plane; TLC%: Predicted total lung capacity percentage.

Table 4 Pre- and post-operative comparisons of spinal thoracic deformity parameters and computed tomography-derived respiratory function parameters

		Entire			Idiopathic			Non-idiopathic
		Pre-operative	Post-operative	P value	Pre-operative	Post-operative	P value	Pre-operative	Post-operative	P value
Cobb angle (°)		64 (46, 84)	28 (17, 50)	< 0.001	47 (38, 65)	18 (16, 26)	< 0.001	82 (56, 96)	47 (34, 63)	< 0.001
AVT (mm)		46 (32, 76)	16 (9, 46)	< 0.001	38 (27, 47)	10 (7, 16)	< 0.001	75 (45, 93)	45 (33, 70)	< 0.001
AVB-R		0.67 (0.36, 0.81)	0.73 (0.50, 0.83)	0.06	0.68 (0.51, 0.75)	0.74 (0.63, 0.80)	0.002	0.66 (0.24, 1.76)	0.57 (0.36, 1.34)	0.99
RAml (°)		39 (26, 59)	27 (20, 50)	< 0.001	32 (22, 39)	22 (17, 27)	< 0.001	55 (28, 72)	48 (34, 67)	0.09
RAsag (°)		21 (13, 38)	19 (13, 39)	0.95	15 (11, 23)	14 (10, 18)	0.05	36 (16, 45)	38 (20, 48)	0.07
TLC%		54 (40, 68)	56 (41, 70)	0.80	64 (59, 75)	67 (55, 75)	0.93	41 (30, 54)	44 (33, 56)	0.58
Lung volume (mL)	Total	2354 (1478, 2974)	2380 (1577, 3077)	0.85	2845 (2545, 3318)	2802 (2471, 3381)	0.94	1500 (880, 2190)	1741 (966, 2299)	0.71
	Right	1269 (837, 1572)	1231 (918, 1653)	0.98	1534 (1375, 1828)	1499 (1300, 1752)	0.67	862 (463, 1156)	960 (533, 1170)	0.58
	Right upper	421 (263, 528)	418 (255, 536)	0.99	490 (427, 600)	489 (34, 575)	1.00	276 (183, 388)	274 (174, 401)	0.91
	Right middle	193 (149, 275)	205 (142, 274)	0.93	257 (191, 316)	235 (190, 312)	0.81	157 (106, 223)	165 (101, 229)	0.80
	Right lower	624 (370, 797)	632 (411, 830)	0.98	778 (671, 992)	786 (652, 933)	0.70	413 (171, 563)	469 (230, 576)	0.53
	Left	1122 (671, 1362)	1131 (674, 1435)	0.83	1285 (1132, 1525)	1297 (1157, 1617)	0.74	701 (407, 1098)	726 (440, 1105)	0.84
	Left upper	568 (365, 726)	585 (368, 750)	0.83	709 (587, 795)	718 (604, 798)	0.77	381 (228, 549)	373 (251, 495)	0.83
	Left lower	512 (267, 644)	560 (285, 686)	0.59	602 (508, 769)	628 (533, 783)	0.53	324 (158, 531)	365 (84, 610)	0.77
Tracheal bifurcation	Min diameter	11.8 (10.3, 13.2)	11.9 (10.8, 13.5)	0.56	12.1 (10.8, 13.7)	12.3 (10.9, 13.9)	0.51	11.4 (9.7, 13.1)	11.7 (10.6, 12.5)	0.89
	Max diameter	17.5 (15.4, 19.7)	17.2 (15.2, 20.0)	0.84	18.3 (16.8, 19.9)	17.6 (16.2, 19.9)	0.63	16.1 (13.9, 18.8)	16.3 (14.1, 19.7)	0.67
	Area	180 (140, 213)	175 (140, 213)	0.65	189 (159, 214)	194 (160, 221)	0.87	153 (125, 196)	162 (123, 213)	0.71
Narrowest tracheal segment	Min diameter	11.8 (9.4, 12.8)	11.4 (9.2, 12.8)	0.88	12.2 (11.8, 13.0)	12.0 (11.8, 13.0)	0.85	9.7 (6.0, 12.2)	10.6 (7.9, 12.0)	0.52
	Max diameter	13.8 (12.4, 15.7)	14.0 (12.9, 15.9)	0.68	14.1 (13.4, 15.7)	14.0 (13.2, 16.2)	0.98	13.3 (11.6, 15.9)	14.1 (11.9, 15.8)	0.64
	Area	136 (94, 160)	139 (105, 166)	0.69	149 (128, 165)	141 (125, 173)	0.95	107 (67, 160)	125 (86, 156)	0.56
Narrowest left bronchus	Min diameter	5.5 (4.5, 7.3)	6.8 (5.2, 8.2)	0.001	6.5 (5.1, 7.4)	7.0 (5.5, 8.6)	0.06	5.3 (4.2, 7.1)	6.3 (4.7, 7.8)	0.006
	Max diameter	7.5 (5.9, 9.9)	9.3 (6.9, 11.3)	< 0.001	8.8 (6.9, 10.4)	10.0 (7.4, 11.4)	0.02	7.3 (5.5, 9.1)	8.6 (6.2, 11.3)	0.003
	Area	35 (22, 61)	55 (31, 79)	< 0.001	47 (31, 65)	59 (35, 81)	0.02	33 (19, 52)	47 (26, 78)	0.003
Narrowest right bronchus	Min diameter	8.9 (7.3, 10.5)	7.8 (6.2, 10.1)	0.16	9.8 (7.6, 11.0)	8.5 (7.0, 10.0)	0.20	8.0 (7.2, 10.2)	7.0 (5.3, 10.2)	0.35
	Max diameter	11.7 (9.1, 14.4)	11.4 (8.6, 13.7)	0.50	12.8 (9.8, 15.4)	11.6 (10.0, 13.9)	0.35	10.9 (8.9, 13.4)	9.4 (7.9, 13.1)	0.67
	Area	88 (58, 123)	77 (48, 110)	0.32	97 (67, 143)	83 (60, 110)	0.28	78 (55, 106)	56 (34, 111)	0.60
Right-to-left bronchial length ratio		0.84 (0.79, 0.86)	0.81 (0.79, 0.86)	0.42	0.84 (0.80, 0.86)	0.82 (0.80, 0.86)	0.43	0.83 (0.77, 0.86)	0.81 (0.77, 0.86)	0.68

Data are presented as median values with interquartile ranges. Airway diameters were measured in millimeters (mm), and cross-sectional areas were expressed in square millimeters (mm²). AVT: Apical vertebral translation; AVB-R: Apical vertebral body-rib ratio; RAml: Rotation relative to anterior midline; RAsag: Rotation relative to sagittal plane; TLC%: Predicted total lung capacity percentage.