Defining Two Components of Shoulder Imbalance: Clavicle Tilt and Trapezial Prominence.

1Department of Orthopedic Surgery, Faculty of Medicine, the University of Tokyo, Tokyo, Japan 2Department of Orthopedic Surgery, Rady Children's Hospital and Health Center, San Diego, California.
Spine (Impact Factor: 2.45). 08/2012; 37(24). DOI: 10.1097/BRS.0b013e31826e2bbb
Source: PubMed

ABSTRACT Study Design. Single center; prospective case series.Objective. To examine two features of shoulder asymmetry (Clavicle Tilt and Trapezial Prominence) and their correlation to radiographic parameters.Summary of Background Data. Shoulder imbalance is one of the more notable aspects of clinical deformity due to scoliosis. However, a discrepancy between radiographic and clinical shoulder balance in adolescent idiopathic scoliosis (AIS) patients has been reported.Methods. A consecutive series of 113 pre-operative right main thoracic Lenke 1 and 2 AIS curves were included. Clavicle angle (tilt), trapezial angle, and ratio of left to right trapezial area were measured on clinical photos. These were correlated with radiographic measurements of T1 tilt, first rib angle, curve magnitudes, and thoracic and lumbar apical translation to C7 plumb line and CSVL.Results. The average age was 14.1yrs. There were 82 Lenke 1 and 31 Lenke 2 curves with an average thoracic Cobb of 52.1°. The clinical clavicle angle ranged from -10.6 to +5.2° ("+" defined as high on the left) and had modest correlation with T1 tilt, thoracic curve size, and thoracic apical deviation (r value, 0.417, 0.437, and 0.408). Medial shoulder trapezial prominence as by the trapezial angle (range: -16.7 to +9.9) and trapezial area ratio (natural log of ratio range; -1.15 to +0.80) correlated well with the radiographic measurements of T1 tilt, first rib angle, and upper thoracic curve size (trapezial angle: 0.713, 0.679, and 0.686; trapezial area ratio: 0.597, 0.595, and 0.653, respectively).Conclusion. Our analysis suggests there are two distinct regions (lateral and medial) of shoulder height asymmetry. Medial differences reflected in trapezial prominence relate to deformity created by upward tilted proximal ribs and T1 tilt. Lateral differences in shoulder symmetry as reflected in the clavicle angle correlate weakly with radiographic measures. This suggests correction of trapezial prominence may be more predictable compared to clavicle angulation following scoliosis surgery.

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    ABSTRACT: Introduction In Lenke 2 curves, there are conflicting data when to include the PTC into the fusion. Studies focusing on Lenke 2 curves are scant. The number of patients with significant postoperative shoulder height difference (SHD) or trunk shift (TS) is as high as 30 % indicating further research. Therefore, the purpose of the current study was to improve understanding of curve resolution and shoulder balance following surgical correction of Lenke 2 curves as well as the identification of radiographic parameters predicting postoperative curve resolution, shoulder and trunk balance in perspective of inclusion/exclusion of the proximal thoracic curve (PTC). Methods This is a retrospective study of a 158 Lenke 2 curves. Serial radiographs were analyzed for the main thoracic curve (MTC), PTC, and lumbar curve (LC), SHD, clavicle angle (CA), T-1 tilt, deviation of the central sacral vertical line (CSVL) off the C7 plumb line.Patients were stratified whether the PTC was included in the fusion (+PTC group, n = 60) or not (−PTC group, n = 98). Intergroup results were studied. Compensatory mechanisms for SHD were studied in detail. Adding-on distally was defined as an increase of the lowest instrumented vertebra adjacent disc angle (LIVDA) >3°. Stepwise regression analyses were performed to establish predictive radiographic parameters. Results At follow-up averaging 24 months significant differences between the +PTC and –PTC group existed for the PTC (24° vs 28°, p p 5° (27 vs 53 %, p p = .04). The number of patients with a new trunk shift (CSVL > 2 cm) was 9 (6 %): 7 in the −PTC vs 2 in the +PTC group (p = .03). Utilization of compensatory mechanisms (99 vs 83 %, p p p = .02). Statistics identified a preoperative ‘left shoulder up’ (p p = .03) predictive for follow-up SHD ≥1.5 cm. A statistical model only for the –PTC group showed 9 parameters highly predictive for a follow-up SHD ≥1.5 cm with highest prediction strength for a PTC >40° (p = .01), a preoperative ‘left shoulder up’ (p p = .02). To account for baseline differences between the +PTC and –PTC groups, 49 matched-pairs were studied. Postoperative differences remained significant between the +PTC and –PTC groups for the PTC (p p = .03) and the rate of loss of MTC >5° (p Conclusion Prediction of a successful surgical outcome for Lenke 2 curves depends on multiple variables, in particular a preoperative left shoulder up, preoperative PTC >40°, MTC correction, and surgical approach. Shoulder balance is not significantly different whether the PTC is included in the fusion or not. But, powerful compensation mechanisms utilized to balance shoulder in the –PTC group can impose changes of trunk alignment, main and compensatory lumbar curves.
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    ABSTRACT: To determine the validity of digital photography as an evaluation method for shoulder balance (ShB) in patients with idiopathic scoliosis. A total of 80 patients were included (mean age 20.3 years; 85% women). We obtained a full x-ray of the vertebral column and front and back clinical photography for all patients. For antero-posterior x-rays we measured the proximal thoracic curve angles (CPT). To evaluate radiological shoulder balance we calculated the clavicle-rib intersection angle (CRIA) and T1-tilt. For clinical photography we measured shoulder height angle (SHA), axilla height angle (AHA) and the left right trapezium angle (LRTA). We analyzed the reliability of the different photographic measurements and the correlation between these and the radiological parameters. The mean magnitude of PTC, CRIA and T1-tilt were 19°, -0.6° and 1.4° respectively. Mean SHA from the front was -1.7°. All photographic measurements revealed an excellent-near perfect intra and inter-observer reliability in both photographic projections. No correlation was found between the ShB and the magnitude of the PTC. A statistically significant correlation was found between clinical balance of the shoulders and radiological balance (r between 0.37 and 0.51). Digital clinical photography appears to be a reliable method for objective clinical measurement of ShB. The correlation between clinical and radiological balance is statistically significant although moderate/weak.
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    ABSTRACT: Study Design. Retrospective case series of surgically treated adolescent scoliosis patientsObjective. To assess the prevalence and independent risk factors of post-operation shoulder imbalance in surgically treated adolescent patients with idiopathic scoliosisSummary of Background Data. Despite recent reports that have identified risk factors for post-operation shoulder imbalance, the relative risks remain unclear.Methods. A retrospective review of 85 consecutive patients treated with thoracic fusion with a minimum 2-year follow-up (mean 3.1 years) was conducted to investigate the patient radiographic measurements and demographics. Shoulder height difference (SHD) was measured as the graded height difference of the soft tissue shadows. A SHD>2 cm indicated an unbalanced shoulder. Patient demographics and radiographic data were studied to determine risk factors for post-operation SHD. The potential risk factors included age, gender, Risser sign, Cobb angle, flexibility, apical vertebral rotation (AVR) of the main curve, UIV level, SHD, and clavicle chest cage angle difference (CCAD). Uni-variate and multi-variate logistic regression analyses were performed to determine the independent risk factors for post-operation shoulder imbalance.Results. Of the 85 patients, 21 patients presented post-operation shoulder imbalance. The uni-variate analysis indicated age, Risser sign, Cobb angle of the main curve, AVR of the main curve, and CCAD as risk factors, but the multi-variate logistic regression analysis showed that only AVR of the main curve and CCAD were independent risk factors for post-operation shoulder imbalance (AVR, p = 0.04, OR: 3.54; CCAD, p = 0.01, OR: 5.10).Conclusions. Post-operation shoulder imbalance was observed in 25% of the surgically treated adolescent patients. The CCAD and AVR of the main thoracic curve were independent risk factors for post-operation shoulder imbalance in surgically treated AIS patients. The significant correlation between CCAD and post-operation shoulder imbalance seen in the present study strongly suggests that the relationship of the shoulder girdle and chest cage has a role in maintaining shoulder balance.
    Spine 06/2013; 38(19). DOI:10.1097/BRS.0b013e31829e0309 · 2.45 Impact Factor