J Korean Soc Spine Surg.  2013 Jun;20(2):35-43. 10.4184/jkss.2013.20.2.35.

Specific Sagittal Curve Patterns of Cervical Spine in Adolescent Idiopathic Scoliosis (AIS)

• Lee SM
• Suk SI
• Moon MS
• Kim SS
• Lee SY
• Yun MG

• KMID: 1430373
• DOI: http://doi.org/10.4184/jkss.2013.20.2.35

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 (> or =+5degrees), lordosis (< or =-5degrees) and straight (-4degrees~+4degrees) 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 follow-up 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.

Keyword

Adolescent idiopathic scoliosis (AIS); Cervical kyphosis; Thoracic rotation; Direct vertebral rotation (DVR)

MeSH Terms

Adolescent
Animals
Braces
Congenital Abnormalities
Follow-Up Studies
Humans
Kyphosis
Lordosis
Retrospective Studies
Scoliosis
Spine

Figure

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  Fig. 1. Negative correlations of sagittal angles between Cervical and Thoracic curves (r=-.496, P <0.01, Pearson coefficients).

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  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.

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  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.

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  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.

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