OBJECTIVETo study the relationship between T1 tilt and cosmetic shoulder balance in adolescent idiopathic scoliosis (AIS) patients.

METHODSSeventy-one Lenke type 2 AIS patients were recruited into the present study from January 2010 to December 2011. There were 61 female and 10 male patients, the average age was (15.1 ± 2.9) years (range 10-18 years); the average Risser sign was 2.8 (range 1-5). The patients were photographed from the back in neutral standing position on level ground wearing underpants. Also, all the patients had a standing posterior-anterior radiograph in a relaxed standing position. The cosmetic shoulder height (CSH), which included cosmetic inner shoulder height (CSHi) and cosmetic outer shoulder height (CSHo), were measured in the photographs. Positive value was defined as left shoulder was higher than the right shoulder, and negative value was defined as right shoulder was higher than the left shoulder. CSH > 5 mm was defined as positive CSH, CSH < -5 mm was defined as negative CSH, -5 mm ≤ CSH ≤ 5 mm was defined as leveled CSH. T1 tilts were measured in the posterior-anterior radiographs. Positive value was defined as the left proximal vertebral body up and right lower vertebral body down, and negative value was defined as the right proximal vertebral body up and left lower vertebral body down. T1 tilt > 5° was defined as positive T1 tilt, T1 tilt < -5° was defined as negative T1 tilt, -5° ≤ T1 tilt ≤ 5° was defined as leveled T1 tilt.

RESULTST1 tilt was found to be significantly correlated with CSHi and CSHo (r = 0.25 and 0.28, P < 0.05).For positive T1 tilt patients, there were 59.0% (36/61) patients with positive CSHo, 37.7% (23/61)with leveled CSHo, and 3.3% (2/61)with negative CSHo.For the patients with leveled T1 tilt, it was 3/10, 5/10 and 2/10.For positive T1 tilt patients, there were 83.6% (51/61) patients with positive CSHi, 11.5% (7/61) with leveled CSHi, and 4.9% (3/61) with negative CSHi; For the patients with leveled T1 tilt, it was 6/10, 2/10 and 2/10.

CONCLUSIONSAlthough positive correlation is found between T1 tilt and cosmetic shoulder balance, positive T1 tilt is not an indicator of higher left shoulder.Elevated left shoulder, leveled shoulders and elevated right shoulder are all found in positive T1 tilt patients.