How can postoperative shoulder imbalance be prevented in adolescent idiopathic scoliosis type 2?


Shoulder elevation; spinal deformity; posterior spinal fusion; level shoulder; frontal alignment

Published online: Jan 20 2023

Clara Berlin, Markus Quante, Björn Thomsen, Mark Koeszegvary, Ferenc Pecsi, Henry Halm

From the Spine Surgery with Scoliosis Center, Schön Klinik Neustadt, Neustadt in Holstein, Germany


Postoperative shoulder imbalance (PSI) is a common complication following adolescent idiopathic scolio- sis (AIS) surgery. There is little data available in literature on prediction of PSI. Prospectively collected data of AIS with thoracic curve (Lenke 2), operated in 2014-2018 at a single scoliosis-center, were analyzed retrospectively using X-rays of whole spine and traction films (TA): age, Cobb-angle of proximal (PC), major thoracic (MC) and lumbar curve (LC), shoulder height [mm], clavicle angle [°], T1-tilt [°], plumb line [mm]. Results as mean ± standard deviation. Change over time (postOP- FU) compared using t-test (≥=0.05). Correlation of preOP parameters and curve correction with PSI (|≥|15mm) was analyzed by correlation (Pearson)- and regression-classification-analysis. 32 AIS, average age of 14±1.3 yrs. FU 16 months (84%). Curve correction was 52.5% (PC), 70.1% (MC), 69.9% (LC), significant change in FU for PC (-2.4°, p>0.05), not for MC, LC (p=0.2, p=0.6). Shoulder height was negative if right- side up: 2.9±15.1mm (preOP), 5.5±15.0 mm (TA), 17.9±14.9mm (postOP), 17.4±8.4mm (FU). 28% had preOP shoulder imbalance, 69% postOP and 44% FU had PSI. Shoulder height on TA correlated to change preOP to FU (r=0.62) and preOP shoulder height (r=-0.85), clavicle angle had strong correlation (r=- 0.81). Regression-classification-analysis: correction of MC>62.4%, 81.5% of cases had PSI; with correction of MC>64.9% and LC>93.2%, 51.9% of cases had PSI. PSI is a common in Lenke2 AIS. In preOP planning TA, shoulder position and clavicle angle should be considered to prevent PSI. Correction of MC should be moderate, overcorrection of the LC avoided.