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Postoperative shoulder imbalance in Lenke Type 1A adolescent idiopathic scoliosis and related factors.

Matsumoto M, Watanabe K, Kawakami N, Tsuji T, Uno K, Suzuki T, Ito M, Yanagida H, Minami S, Akazawa T - BMC Musculoskelet Disord (2014)

Bottom Line: Clavicle angle at follow-up correlated weakly but significantly with preoperative clavicle angle (r = 0.34, p = 0.001) and with the correction rates of the main thoracic curve (r = 0.34, p = 0.001); it correlated negatively with the proximal curve spontaneous correction rate (r=-0.21, p = 0.034).The clavicle angle at follow-up was significantly larger in patients with PS-only constructs (PS 2.1 degrees vs. hybrid 0.9, p = 0.02), and tended to be smaller in patients with distal adding-on (adding-on 1.1 vs. non adding-on 2.0, p = 0.09).PSI was more common with better correction of the main curve (using PS constructs), in patients with a larger preoperative clavicle angle, and with a larger and more rigid proximal curve.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Keio University, Shinanomachi 35, Shinjuku-ku, Tokyo #160-8582, Japan. morio@a5.keio.jp.

ABSTRACT

Backgrounds: The purpose of this study was to investigate the occurrence and factors associated with postoperative shoulder imbalance (PSI) in Lenke type 1A curve.

Methods: This study included 106 patients with Lenke Type 1A curve who were followed up more than two years after posterior correction surgery. Pedicle screw (PS) constructs were used in 84 patients, and hybrid constructs in 22. The upper instrumented vertebra was rostral to the upper-end vertebra (UEV) in 70 patients, at UEV in 26, and below UEV in 10. The clavicle angle and T1 tilt angle were measured as PSI indicators, and correlations between radiographic parameters of shoulder balance and other radiographic parameters and associations between PSI and clinical parameters were investigated. For statistical analyses, paired and unpaired t-tests were used.

Results: The mean Cobb angles of the main and proximal thoracic curves were 54.6 ± 9.5 and 26.7 ± 7.9 degrees before surgery, 14.5 ± 7.5, and 14.9 ± 7.1 at follow-up. Clavicle angle and T1 tilt angle were -2.9 ± 2.8 and -2.6 ± 6.3 before surgery, 2.4 ± 2.8 and 4.4 ± 4.3 immediately after surgery, and 1.8 ± 2.1 and 3.4 ± 5.5 at follow-up. Twenty patients developed distal adding-on. Clavicle angle at follow-up correlated weakly but significantly with preoperative clavicle angle (r = 0.34, p = 0.001) and with the correction rates of the main thoracic curve (r = 0.34, p = 0.001); it correlated negatively with the proximal curve spontaneous correction rate (r=-0.21, p = 0.034). The clavicle angle at follow-up was significantly larger in patients with PS-only constructs (PS 2.1 degrees vs. hybrid 0.9, p = 0.02), and tended to be smaller in patients with distal adding-on (adding-on 1.1 vs. non adding-on 2.0, p = 0.09).

Conclusions: PSI was more common with better correction of the main curve (using PS constructs), in patients with a larger preoperative clavicle angle, and with a larger and more rigid proximal curve. Distal adding-on may compensate for PSI.

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Related in: MedlinePlus

Radiographic measurements. A. Coronal balance; a distance between the central sacral vertical line and the C7 plumb line (right; positive, left; negative) in the standing postero-anterior radiograph. B. Sagittal balance: a distance between the C7 plumb line and the posterosuperior corner of the sacrum in the lateral standing radiograph. (anterior; positive, posterior; negative). C. Clavicle angle: the angulation of a horizontal line and the tangential line connecting the highest two points of each clavicle (left side up; positive, left side down; negative). D. T1 tilt angle; the angulation of the upper endplate of T1 to the horizontal line (left side up; positive, left side down; negative).
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Fig1: Radiographic measurements. A. Coronal balance; a distance between the central sacral vertical line and the C7 plumb line (right; positive, left; negative) in the standing postero-anterior radiograph. B. Sagittal balance: a distance between the C7 plumb line and the posterosuperior corner of the sacrum in the lateral standing radiograph. (anterior; positive, posterior; negative). C. Clavicle angle: the angulation of a horizontal line and the tangential line connecting the highest two points of each clavicle (left side up; positive, left side down; negative). D. T1 tilt angle; the angulation of the upper endplate of T1 to the horizontal line (left side up; positive, left side down; negative).

Mentions: Each patient’s radiographic data were analyzed for thoracic kyphosis (T5-T12), apical translation of the main thoracic curve, coronal and sagittal balances, and the Cobb angles of the lumbar curve and the main and proximal thoracic curves [15]. Side benders, right and left side bending films taken in the supine position, were taken and the flexibility was calculated as (the Cobb angle in the standing film-that in the side bender)/the Cobb angle in the standing film × 100 (%). The correction rate was calculated as (the preoperative Cobb angle – the postoperative or the follow-up Cobb angle)/the preoperative Cobb angle in the standing film × 100 (%). The coronal balance was defined as a distance between the central sacral vertical line and the C7 plumb line (right; positive, left; negative) in the standing postero-anterior radiograph, and the sagittal balance as a distance between the C7 plumb line and the posterosuperior corner of the sacrum in the lateral standing radiograph (Figure 1) [15]. The clavicle angle and T1 tilt angle were measured and used to indicate shoulder balance [15]. The clavicle angle was defined by the angulation of a horizontal line and the tangential line connecting the highest two points of each clavicle; the T1 tilt angle was defined as the angulation of the upper endplate of T1 to the horizontal line. A clavicle angle and T1 tilt angle were positive when the left side was raised (Figure 1).Figure 1


Postoperative shoulder imbalance in Lenke Type 1A adolescent idiopathic scoliosis and related factors.

Matsumoto M, Watanabe K, Kawakami N, Tsuji T, Uno K, Suzuki T, Ito M, Yanagida H, Minami S, Akazawa T - BMC Musculoskelet Disord (2014)

Radiographic measurements. A. Coronal balance; a distance between the central sacral vertical line and the C7 plumb line (right; positive, left; negative) in the standing postero-anterior radiograph. B. Sagittal balance: a distance between the C7 plumb line and the posterosuperior corner of the sacrum in the lateral standing radiograph. (anterior; positive, posterior; negative). C. Clavicle angle: the angulation of a horizontal line and the tangential line connecting the highest two points of each clavicle (left side up; positive, left side down; negative). D. T1 tilt angle; the angulation of the upper endplate of T1 to the horizontal line (left side up; positive, left side down; negative).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4230354&req=5

Fig1: Radiographic measurements. A. Coronal balance; a distance between the central sacral vertical line and the C7 plumb line (right; positive, left; negative) in the standing postero-anterior radiograph. B. Sagittal balance: a distance between the C7 plumb line and the posterosuperior corner of the sacrum in the lateral standing radiograph. (anterior; positive, posterior; negative). C. Clavicle angle: the angulation of a horizontal line and the tangential line connecting the highest two points of each clavicle (left side up; positive, left side down; negative). D. T1 tilt angle; the angulation of the upper endplate of T1 to the horizontal line (left side up; positive, left side down; negative).
Mentions: Each patient’s radiographic data were analyzed for thoracic kyphosis (T5-T12), apical translation of the main thoracic curve, coronal and sagittal balances, and the Cobb angles of the lumbar curve and the main and proximal thoracic curves [15]. Side benders, right and left side bending films taken in the supine position, were taken and the flexibility was calculated as (the Cobb angle in the standing film-that in the side bender)/the Cobb angle in the standing film × 100 (%). The correction rate was calculated as (the preoperative Cobb angle – the postoperative or the follow-up Cobb angle)/the preoperative Cobb angle in the standing film × 100 (%). The coronal balance was defined as a distance between the central sacral vertical line and the C7 plumb line (right; positive, left; negative) in the standing postero-anterior radiograph, and the sagittal balance as a distance between the C7 plumb line and the posterosuperior corner of the sacrum in the lateral standing radiograph (Figure 1) [15]. The clavicle angle and T1 tilt angle were measured and used to indicate shoulder balance [15]. The clavicle angle was defined by the angulation of a horizontal line and the tangential line connecting the highest two points of each clavicle; the T1 tilt angle was defined as the angulation of the upper endplate of T1 to the horizontal line. A clavicle angle and T1 tilt angle were positive when the left side was raised (Figure 1).Figure 1

Bottom Line: Clavicle angle at follow-up correlated weakly but significantly with preoperative clavicle angle (r = 0.34, p = 0.001) and with the correction rates of the main thoracic curve (r = 0.34, p = 0.001); it correlated negatively with the proximal curve spontaneous correction rate (r=-0.21, p = 0.034).The clavicle angle at follow-up was significantly larger in patients with PS-only constructs (PS 2.1 degrees vs. hybrid 0.9, p = 0.02), and tended to be smaller in patients with distal adding-on (adding-on 1.1 vs. non adding-on 2.0, p = 0.09).PSI was more common with better correction of the main curve (using PS constructs), in patients with a larger preoperative clavicle angle, and with a larger and more rigid proximal curve.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Keio University, Shinanomachi 35, Shinjuku-ku, Tokyo #160-8582, Japan. morio@a5.keio.jp.

ABSTRACT

Backgrounds: The purpose of this study was to investigate the occurrence and factors associated with postoperative shoulder imbalance (PSI) in Lenke type 1A curve.

Methods: This study included 106 patients with Lenke Type 1A curve who were followed up more than two years after posterior correction surgery. Pedicle screw (PS) constructs were used in 84 patients, and hybrid constructs in 22. The upper instrumented vertebra was rostral to the upper-end vertebra (UEV) in 70 patients, at UEV in 26, and below UEV in 10. The clavicle angle and T1 tilt angle were measured as PSI indicators, and correlations between radiographic parameters of shoulder balance and other radiographic parameters and associations between PSI and clinical parameters were investigated. For statistical analyses, paired and unpaired t-tests were used.

Results: The mean Cobb angles of the main and proximal thoracic curves were 54.6 ± 9.5 and 26.7 ± 7.9 degrees before surgery, 14.5 ± 7.5, and 14.9 ± 7.1 at follow-up. Clavicle angle and T1 tilt angle were -2.9 ± 2.8 and -2.6 ± 6.3 before surgery, 2.4 ± 2.8 and 4.4 ± 4.3 immediately after surgery, and 1.8 ± 2.1 and 3.4 ± 5.5 at follow-up. Twenty patients developed distal adding-on. Clavicle angle at follow-up correlated weakly but significantly with preoperative clavicle angle (r = 0.34, p = 0.001) and with the correction rates of the main thoracic curve (r = 0.34, p = 0.001); it correlated negatively with the proximal curve spontaneous correction rate (r=-0.21, p = 0.034). The clavicle angle at follow-up was significantly larger in patients with PS-only constructs (PS 2.1 degrees vs. hybrid 0.9, p = 0.02), and tended to be smaller in patients with distal adding-on (adding-on 1.1 vs. non adding-on 2.0, p = 0.09).

Conclusions: PSI was more common with better correction of the main curve (using PS constructs), in patients with a larger preoperative clavicle angle, and with a larger and more rigid proximal curve. Distal adding-on may compensate for PSI.

Show MeSH
Related in: MedlinePlus