Journal List > J Korean Soc Spine Surg > v.20(2) > 1076009

Lee, Suk, Moon, Kim, Lee, and Yun: Specific Sagittal Curve Patterns of Cervical Spine in Adolescent Idiopathic Scoliosis (AIS)

Abstract

Study Design

A retrospective study.

Objectives

To evaluate the sagittal alignment of cervical spine in AIS.

Summary of Literature Review

Little has been known about the sagittal curve patterns of cervical spine in AIS patients.

Materials and Methods

One-hundred-thirty-three AIS patients were checked by scanographs and followed up for more than 2 years were divided into cervical kyphosis (≥+5°), lordosis (≤-5°) and straight (-4°~+4°) groups according to the sagittal curves of cervical spine (C2~C7). Each group was evaluated for thoracic kyphosis, lumbar lordosis, sagittal balance and Cobb's angle on coronal plane. Of the patients, 49 were treated by braces, 84 were surgically corrected (rod derotation in 52, direct vertebral rotation (DVR) in 32).

Results

At the initial radiographs, cervical kyphosis was found in 97, lordosis in 23 and straight in 13 patients. In the kyphosis group, cervical kyphosis showed typical patterns of angular kyphosis. Thoracic and upper T-kyphosis (T1~T5) were lower than those in the cervical lordosis group (p=0.000, 0.001, respectively.) Other factors showed no significant differences between the groups. Patients treated by conservative management or by rod derotation had no significant differences in cervical kyphosis during the followup periods, though the thoracic hypokyphosis was surgically corrected. On the contrary, patients who were treated by DVR restored cervical lordosis (14/32=43.8%) from initial state showed significant differences in both conservative and rod derotation groups (p=0.008, 0.002, respectively)

Conclusions

Cervical kyphosis in AIS was a compensatory curve correlated with both thoracic hypokyphosis and rotational deformity. Rotational corrections should be considered during the surgical treatment.

REFERENCES

1. Hilibrand AS, Tannenbaum DA, Graziano GP, Loder RT, Hensinger RN. The sagittal alignment of the cervical spine in adolescent idiopathic scoliosis. J Pediatr Orthop. 1995; 15:627–32.
crossref
2. Canavese F, Turcot K, De Rosa V, de Coulon G, Kaelin A. Cervical spine sagittal alignment variations following posterior spinal fusion and instrumentation for adolescent idiopathic scoliosis. Eur Spine J. 2011; 20:1141–8.
crossref
3. Winter RB, Lovell WW, Moe JH. Excessive thoracic lordosis and loss of pulmonary function in patients with idiopathic scoliosis. J Bone Joint Surg Am. 1975; 57:972–6.
crossref
4. Berthonnaud E, Dimnet J, Roussouly P, Labelle H. Analysis of the sagittal balance of the spine and pelvis using shape and orientation parameters. J Spinal Disord Tech. 2005; 18:40–7.
crossref
5. Takeshima T, Omokawa S, Takaoka T, Araki M, Ueda Y, Takakura Y. Sagittal alignment of cervical flexion and extension: lateral radiographic analysis. Spine (Phila Pa 1976). 2002; 27:E348–55.
6. Penning L. Acceleration injury of the cervical spine by hy-pertranslation of the head: effect of normal translation of the head on cervical spine motion. Eur Spine J. 1992; 1:7–19.
7. Faro FD, Marks MC, Pawelek J, Newton PO. Evaluation of a functional position for lateral radiograph acquisition in adolescent idiopathic scoliosis. Spine (Phila Pa 1976). 2004; 29:2284–9.
crossref
8. Marks M, Stanford C, Newton P. Which lateral radiographic positioning technique provides the most reliable and functional representation of a patient's sagittal balance? Spine (Phila Pa 1976). 2009; 34:949–54.
crossref
9. Bernhardt M, Bridwell KH. Segmental analysis of the sagittal plane alignment of the normal thoracic and lumbar spines and thoracolumbar junction. Spine (Phila Pa 1976). 1989; 14:717–21.
crossref
10. Harrison DE, Harrison DD, Janik TJ, Holland B, Siskin LA. Slight head extension: does it change the sagittal cervical curve? Eur Spine J. 2001; 10:149–53.
crossref
11. Erkan S, Yercan HS, Okcu G, Ozalp RT. The influence of sagittal cervical profile, gender and age on the thoracic kyphosis. Acta Orthop Belg. 2010; 76:675–80.
12. Lee SM, Suk SI, Chung ER. Direct vertebral rotation: a new technique of three-dimensional deformity correction with segmental pedicle screw fixation in adolescent idiopathic scoliosis. Spine (Phila Pa 1976). 2004; 29:343–9.
crossref

Figures and Tables%

Fig. 1.
Negative correlations of sagittal angles between Cervical and Thoracic curves (r=-.496, P <0.01, Pearson coefficients).
jkss-20-35f1.tif
Fig. 2.
(A, B) A twelve-year-old AIS patient with mild thoracic scoliosis showed cervical kyphosis of 6 degrees at the initial radiographs. She had trunk balance both in coronal and sagittal planes. (C, D) The curves were not progressed in the coronal plane during the followup periods of 30 months. Cervical curve was remained and was checked cervical kyphosis of 8 degrees in the sagittal plane.
jkss-20-35f2.tif
Fig. 3.
(A, B) A fourteen-year-old AIS patient with double major curves showed cervical kyphosis of 18 degrees and thoracic hypokyphosis of 24 degrees (T1~T12) at the initial radiographs. (C, D) The patient was operated by pedicle screw fixation with rod derotation maneuver. Thoracic hypokyphosis was well corrected to normokyphosis of 34 degrees. However, cervical kyphosis was not changed though thoracic hyphokyphosis was well corrected. Preoperative cervical kyphosis of 18 degrees was slightly changed to kyphosis of 15 degrees with no significant difference.
jkss-20-35f3.tif
Fig. 4.
(A, B) A fifteen-year-old AIS patient with King type II curve showed cervical kyphosis of 7 degrees and thoracic hypokyphosis of 26 degrees at the initial radiographs. (C, D) She was operated by direct vertebral rotation (DVR). Postoperative cervical curve in the sagittal plane showed a noticeable change. Preoperative cervical kyphosis of 7 degrees was changed to cervical lordosis of 5 degrees after the operation with a statistically significant difference.
jkss-20-35f4.tif
Table 1.
Characteristics in Cervical Curves Groups
Group Total Kyphosis Lordosis Straight p*
Sagittal angle
C- angle(˚) 6.9±10.2 11.6±6.1 -10.3±5.9 2.0±2.0 0.000
T-angle(˚) 27.7 25.7 35.7 29.0 0.000
L-angle(˚) -42.4 -42.8 -42.5 -38.9 >0.05
Sagittal balance
C2 (mm) 4.4 2.5 10.3 8.2 >0.05
C7 (mm) -9.6 -11.9 -2.5 -5.2 >0.05
L1 (mm) 10.3 12.5 5.0 3.8 >0.05
Coronal angle
T-curves 42.4 41.8 43.9 43.6 >0.05
L-curves 30.8 30.5 29.9 34.3 >0.05
No. of pts (%) 133 97(72.9) 23(17.3) 13(9.8)
T-Hypok (<25) 52 47 2 3 0.000
Normok(>25) 81 50 21 10
Sagittal balance 71 50 15 6
Sagittal imbalance
Negative (<-20mm) 44 35 5 4 >0.05
Positive (>+20mm) 18 12 3 3
Coronal Curves
Single T 81 63 11 7
Double T 23 16 4 3
Double M 20 14 3 3
L or T-L 9 6 3 0

*p: statistics between kyphosis group and lordosis group

Table 2.
Changes of Curves Angles and Types according to the Treatment Methods
Conservative Derotation DVR p*
No. of pts 49 52 32
C-kyphosis (initial) 35 (37) 34 (37) 12 (23)
Lordosis(initial) 7 (6) 11 (9) 14 (8)
Straight(initial) 7 (6) 7 (6) 6 (1)
T hypoK (initial) 16 (18) 8 (22) 4 (12)
NormoK (initial) 33 (31) 44 (30) 28 (20)
Cervical angle
Initial 7.4±8.1 6.1±10.4 7.6±12.5
Last F/U 7.1±6.9 3.9±11.0 -0.1±11.9
Corrected angle -0.3 -2.2 -7.7 0.018
Thoracic angle
Initial 27.2 27.4 29.1
Last F/U 28.7 33.0 34.7
Corrected angle 1.5 5.6 5.6

*p: statistics between DVR group and Derotation group

TOOLS
Similar articles