Purpose: This is the first systematic review and meta-analysis to detect the incidence and risk factors for postoperative shoulder imbalance (PSI) in scoliosis.
Methods: A systematic online search was conducted to identify eligible studies. ES, OR and WMD with 95% CI were used to assess the incidence and risk factors associated with PSI.
Results: Twenty-six studies were recruited. The pooled incidence of PSI was 25% (95% CI 20-31%). The incidence in Lenke 1 AIS, Lenke 2 AIS, Lenke 5 AIS and mixed AIS was 20% (9-31%), 26% (15-37%), 31% (17-45%) and 27% (19-35%), respectively. Using RSH ≥10 mm as the criterion of PSI, we found that preoperative LC, postoperative RSH, correction rate of MTC at follow-up were primary risk factors for PSI at follow-up. In the analysis of using RSH ≥20 mm as the criterion of PSI, our results showed that Risser sign, postoperative RSH, correction rate of PTC at follow-up, and LC at follow-up were contributing to PSI. Besides, scoliosis patients with PSI were more likely to suffer from adding-on.
Conclusions: The pooled incidence of PSI in scoliosis was 25%. Risser sign, preoperative LC, postoperative RSH, correction rate of PTC at follow-up, correction rate of MTC at follow-up, and LC at follow-up were risk factors for PSI in patients with scoliosis. Adding-on might be a compensatory mechanism for PSI. It is recommended that (1) sufficient correction of PTC and moderate correction of MTC and LC in the operation should be performed; (2) PSI should be prevented not only for the patients' postoperative appearance, but also for preventing the adding-on phenomenon.
Keywords: Meta-analysis; Postoperative shoulder imbalance; Risk factors; Scoliosis.