Table 3 Univariate analysis of shoulder imbalance risk factors
Parameters | Balanced shoulder | Imbalanced shoulder | P |
|---|---|---|---|
Demographics | |||
 Sex (male/female) | 4/13 | 2/5 | 1.000 |
 Diagnosis (congenital/not) | 5/12 | 4/3 | 0.356 |
 Age at implantation | 9.3 ± 2.3 | 11.0 ± 1.6 | 0.094 |
 Age at fusion | 12.7 ± 1.5 | 13.9 ± 1.2 | 0.091 |
 Risser sign at implantation (0/1) | 15/2 | 6/1 | 1.000 |
 Risser sign at fusion (4/5) | 3/14 | 1/6 | 1.000 |
 Treatment duration (y) | 3.4 ± 1.6 | 2.8 ± 1.0 | 0.429 |
 Left/right curve | 4/13 | 3/4 | 0.374 |
Surgery-related | |||
 No. of lengthening surgeries | 2.5 ± 1.7 | 2.4 ± 1.0 | 0.885 |
Single/dual rod(s) | |||
 Implantation | 13/4 | 6/1 | 1.000 |
 Prefusion | 8/9 | 5/2 | 0.386 |
UIV(T2 and above/T3 and below) | |||
 Growing rods | 12/5 | 4/3 | 0.647 |
 Fusion | 12/5 | 2/5 | 0.085 |
LIV(L3 and above/L4 and below) | |||
 Growing rods | 8/9 | 2/5 | 0.653 |
 Fusion | 12/5 | 5/2 | 1.000 |
Upper instrument (hook or hybrid/no hook) | |||
 Growing rods | 11/6 | 5/2 | 1.000 |
 Fusion | 3/14 | 2/5 | 0.608 |
 Fixation of the apical region/not at fusion | 11/6 | 3/4 | 0.393 |
 Osteotomy/not at fusion | 3/14 | 2/5 | 0.608 |
Radiographic | |||
MC Cobb angle (°) | |||
 Preimplantation | 98 ± 20 | 93 ± 26 | 0.637 |
 Postimplantation | 53 ± 18 | 45 ± 26 | 0.359 |
 Prefusion | 60 ± 19 | 57 ± 24 | 0.756 |
 Follow-up | 41 ± 17 | 32 ± 18 | 0.252 |
 Change | 57 ± 12 | 61 ± 17 | 0.506 |
PTC Cobb angle (°) | |||
 Preimplantation | 44 ± 20 | 42 ± 15 | 0.815 |
 Postimplantation | 30 ± 14 | 29 ± 10 | 0.947 |
 Prefusion | 30 ± 14 | 30 ± 9 | 0.890 |
 Follow-up | 21 ± 8 | 21 ± 6 | 0.895 |
 Change | 22 ± 14 | 21 ± 13 | 0.887 |
Flexibility (preimplantation) | |||
 PTC | 38 ± 27 | 29 ± 12 | 0.433 |
 MC | 19 ± 17 | 19 ± 15 | 0.976 |
Thoracic kyphosis | |||
 Preimplantation | 46 ± 25 | 52 ± 25 | 0.575 |
 Postimplantation | 34 ± 15 | 31 ± 17 | 0.689 |
 Prefusion | 39 ± 15 | 47 ± 12 | 0.239 |
 Follow-up | 33 ± 12 | 39 ± 12 | 0.272 |
 Change | 13 ± 22 | 13 ± 19 | 0.983 |
Lumbar lordosis | |||
 Preimplantation | 48 ± 15 | 48 ± 14 | 0.980 |
 Postimplantation | 40 ± 13 | 44 ± 16 | 0.511 |
 Prefusion | 56 ± 14 | 61 ± 13 | 0.384 |
 Follow-up | 53 ± 10 | 52 ± 16 | 0.888 |
 Change | −5 ± 18 | −4 ± 17 | 0.955 |
C7PL-CSVL (cm) | |||
 Preimplantation | 3.1 ± 2.4 | 3.0 ± 3.2 | 0.936 |
 Postimplantation | 2.4 ± 1.6 | 2.5 ± 2.4 | 0.896 |
 Prefusion | 2.5 ± 1.6 | 2.1 ± 1.8 | 0.559 |
 Follow-up | 2.9 ± 1.6 | 2.2 ± 1.7 | 0.392 |
 Change | 0.2 ± 3.4 | 0.8 ± 3.0 | 0.699 |
C7PL-SVA (cm) | |||
 Preimplantation | 2.7 ± 2.0 | 3.7 ± 2.0 | 0.303 |
 Postimplantation | 3.3 ± 1.9 | 2.9 ± 1.4 | 0.641 |
 Prefusion | 2.2 ± 1.8 | 3.9 ± 2.5 | 0.074 |
 Follow-up | 3.0 ± 2.4 | 3.5 ± 2.0 | 0.685 |
 Change | −0.3 ± 3.2 | 0.2 ± 2.6 | 0.722 |
Shoulder Balance | |||
RSH (mm) | |||
 Preimplantation | 23.7 ± 16.1 | 24.2 ± 16.9 | 0.942 |
 Postimplantation | 16.7 ± 5.9 | 18.1 ± 13.8 | 0.807 |
 Prelengthening | 18.6 ± 10.2 | 16.7 ± 9.1 | 0.680 |
 Postlengthening | 18.4 ± 13.6 | 16.9 ± 6.7 | 0.792 |
 Prefusion | 18.3 ± 11.8 | 19.5 ± 9.8 | 0.806 |
 Postfusion | 12.5 ± 6.4 | 25.8 ± 9.5 | 0.002 |
 Follow-up | 7.3 ± 4.0 | 27.5 ± 7.7 | < 0.001 |
RSB classification (balanced/unbalanced) | |||
 Preimplantation | 7/10 | 4/3 | 0.659 |
 Postimplantation | 10/7 | 4/3 | 1.000 |
 Prelengthening | 9/8 | 5/2 | 0.653 |
 Postlengthening | 11/6 | 5/2 | 1.000 |
 Prefusion | 9/8 | 2/5 | 0.386 |
 Postfusion | 13/4 | 1/6 | 0.009 |
 Follow-up | 17/0 | 0/7 | < 0.001 |
Other Parameters | |||
CA (°) | |||
 Preimplantation | 6.8 ± 4.2 | 5.1 ± 4.2 | 0.392 |
 Postimplantation | 4.0 ± 2.9 | 3.6 ± 4.2 | 0.814 |
 Prefusion | 3.8 ± 2.0 | 3.3 ± 1.3 | 0.926 |
 Postfusion | 3.4 ± 2.7 | 5.8 ± 3.3 | 0.082 |
 Follow-up | 1.9 ± 0.9 | 4.3 ± 2.6 | 0.044 |
T1T (°) | |||
 Preimplantation | 18.8 ± 15.9 | 17.9 ± 15.1 | 0.900 |
 Postimplantation | 12.7 ± 10.5 | 13.6 ± 11.8 | 0.846 |
 Prefusion | 16.1 ± 13.1 | 14.9 ± 9.5 | 0.822 |
 Postfusion | 15.0 ± 15.1 | 19.3 ± 13.5 | 0.523 |
   Follow-up | 11.3 ± 11.8 | 16.5 ± 7.2 | 0.295 |