Abstract
Introduction
Surgical correction for adolescent idiopathic scoliosis (AIS) results in a good correction of the deformity, but it was previously shown that the motion of the spine is diminished during stationary bending movements.1,2 It is unknown whether this is also true for spinal motion during gait and whether the unfused segments and shoulders compensate for the loss of motion of the fused segments. Therefore, this study aimed to identify whether a reduced range of motion (ROM) of the fused segments during gait can be demonstrated, and if and how this is compensated in the unfused spinal segments, and/or shoulders.
Material and Methods
Twelve AIS patients who underwent a surgical scoliosis correction underwent gait analysis preoperatively and at three and twelve months follow-up. The ROM of the shoulders and the trunk at T5-T7, T10-T12, L1-L3 and L3-L5 relative to the pelvis was measured during gait on a treadmill at 5 km/h The ROM was measured in the frontal, sagittal and transverse plane using retro-reflective skin markers (VICON). Spinal levels above T5 and below L3 were left unfused. A two-way repeated measures ANOVA with factors surgery and trunk locations was performed. For the shoulders, a one-way repeated measures ANOVA with factor surgery was used. Post hoc Bonferroni tests were used to analyze differences between pre-operative, 3 months and 12 months follow-up measurements.
Results
At the measured trunk locations, ROM relative to the pelvis showed a significant decrease after surgery in the sagittal (p = 0.027) and transverse planes (p = 0.004) and an increase in the frontal plane (p = 0.049). No interactions between surgery and trunk location was found, indicating that the effects of surgery on the ROM did not differ between the fused and unfused trunk locations. Post hoc analysis revealed a small but significant decrease of the mean ROM of the trunk locations only in the transverse plane ROM from 7.1 degrees (SD=2.1) pre-operative to 5.1 degrees (SD=1.5) at 3 months (p = 0.004) and 5.1 degrees (SD=1.9) at 12 months follow-up (p = 0.012). A significant effect in shoulder ROM after surgery was found in the transverse plane (p = 0.024) but not in the frontal (p = 0.20) and sagittal planes (p = 0.25). Shoulder ROM in the transverse plane decreased from 11.2 degrees (SD=4.3) pre-operative to 8.2 degrees (SD=3.7) at 3 months follow-up (p = 0.005). Though, at 12 months follow-up the decrease in ROM was not significantly different in comparison to pre-operative with a ROM of 9.4 degrees (SD=2.9).
Conclusion
Spinal fusion resulted in a small decrease in sagittal and transverse plane ROM of the trunk segments and the shoulders during gait, whereas frontal plane ROM increased. Shoulder ROM in the transverse plane recovered to pre-operative values at 12 months follow-up. The decrease in trunk ROM occurred in both fused and unfused spinal segments. No increased compensatory motion was detected at the unfused areas of the spine or the shoulder girdle. Adolescent patients manage to maintain near pre-operative trunk and shoulder ROM during gait despite long spinal fusion. This may well explain why patients function so well in daily life after surgery.
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