Shoulder Imbalance in Adolescent Idiopathic Scoliosis: A Systematic Review of the Current State of the Art.

Abstract

Shoulder imbalance (SI) is among the most rated manifestations of adolescent idiopathic scoliosis (AIS) pointed to by patients and spine surgeons. It serves as a criterion to assess the outcome of scoliosis surgery and is also a cause of dissatisfaction for the patients postoperatively. Despite the availability of multiple studies on this issue, a comprehensive survey of the risk factors and preventive measures has yet to be elucidated. The present study aimed to highlight the most recent approach to the evaluation and management of SI, as well as medical counseling about the expectations and limitations of the surgery. A systematic literature review using electric databases was conducted, including PubMed, Embase, the Cochrane Library, and Google Scholar, with a well-defined search strategy on SI definition, risk factors, and preventive and surgical recommendations. A total of 69 articles were identified; SI > 2 cm was the most used cut-off, and its risk factors included the main thoracic Cobb angle > 80˚, preoperative level shoulder, high left shoulder, and higher Risser grade. The most stated strategies to preclude SI were the sufficient correction of the proximal thoracic curve, and moderate correction of the main thoracic and lumbar curve (LC). Shoulder imbalance should be prevented not only for appearance or satisfaction but also for possible complications such as distal adding-on, new LC progression, or trunk shift postoperatively in AIS patients.