Clinical Evaluation of the Anterior Chest Wall Deformity in Thoracic Adolescent Idiopathic Scoliosis.

By London Spine

Clinical Evaluation of the Anterior Chest Wall Deformity in Thoracic Adolescent Idiopathic Scoliosis.

Spine (Phila Pa 1976). 2011 Oct 24;

Authors: Mao SH, Qiu Y, Zhu ZZ, Zhu F, Liu Z, Wang B

Study Design. A retrospective radiographic study of pre and post-operative anterior chest wall shape in thoracic adolescent idiopathic scoliosis (AIS).Objective. To assess the anterior chest wall deformity and define its relationship with other deformed components in AIS. The surgical influence on the deformed chest wall contour was also evaluated to improve the clinical recognition of the risk factors associated with aggravated chest wall shape postoperatively.Summary of Background Data. Anterior chest wall deformity is one of the major cosmetic concerns that may be attributable to rotational coupling in AIS. Patients could be quite different in their anterior chest wall appearance with similar spinal angulation. The surgical improvement of this deformed chest wall shape is also quite elusive and the reverse could also happen despite excellent correction in Cobb angle. We wonder whether or not the anterior chest wall deformity is independent in the severity from the co-development of spinal curvature, translation, and vertebral rotation.Methods. In this retrospective study, 110 sets of CT scans, 70 of which with both pre and post operative images, were retrieved and analyzed. The Image J software (NIH) was utilized to manipulate formatted CT scans into 3-dimensional anterior chest wall reconstructions. Multiple anterior and posterior deformity parameters were evaluated, correlated and compared.Results. The pre-op Cobb angle of major thoracic curve, chest wall angle (CWA), rib hump(RH), angle of the sternum relative to the apical vertebral body(?), Sternum-Rib Ratio (S-R Ratio), apical vertebral rotation (AVR) and angle of trunk rotation (ATR) averaged 54.4±15.2°, 5.4±3.9°, 14.7±5.4°, 80.5±7.8°, 1.3±0.2, 12.3±6.5° and 8.8± 4.6°, respectively. The thoracic Cobb angle demonstrated moderate correlation with CWA, RH, ?, S-R Ratio, AVR and ATR(r = 0.377, 0.604, -0.401, 0.514, 0.530 and 0.517, respectively, p<0.001). The rib hump demonstrated moderate correlation with AVR(r = 0.546, p<0.001). No statistically significant relationship between CWA and rib hump, AVR, ATR were detected (r = 0.129, 0.043, -0.039, p>0.05). The AVR demonstrated significant correlation with?and S-R Ratio (r = -0.757, p<0.001; r = 0.213, p<0.05). Averaged CWA with different curve apex showed a normal distribution shape, with the highest at T9 level. The post-op thoracic Cobb angle, S-R Ratio, AVR and ATR improved significantly (p<0.05), with the exception of the post-op CWA and?(p>0.05). Post-op |CWA| aggravated in 52.8% of the patients, with 38.6% beyond 5°, which showed a significantly lower average pre-op CWA (3.0±2.8°) compared with the rest patients with decreased CWA (7.9±3.1°) (p<0.001).Conclusion. Idiopathic scoliosis is associated with distinctive anterior chest wall deformity, with its variations partially attributable to Cobb angle and apex location, but not directly correlated with apical vertebral rotation. Incidence of aggravated post-op anterior chest wall shape is notable in our study, and patients should be informed of this risk beforehand. Small pre-op CWA and apical vertebra located above T9 were associated with relatively higher risk of post-op chest wall shape aggravation.

PMID: 22020591 [PubMed – as supplied by publisher]