Analysis of Pelvic Obliquity in Standing Position and during Walking in Patients with Different Types of Juvenile Idiopathic Scoliosis

To analyze the correlation between juvenile idiopathic scoliosis (JIS) patients with lumbar and thoracic scoliosis and the degree of pelvis obliquity in standing position and during walking.

The patients with JIS(Cobb≥10°) admitted into Peking Union Medical College Hospital from September 2020 to December 2022 and non-JIS patients(Cobb < 10°) during the same period were retrospectively included. According to the results of anteroposterior X-ray of the whole spine in the standing position, JIS patients were divided into a group with lumbar/thoracolumbar scoliosis (group A) and a group without lumbar/thoracolumbar scoliosis (group B). The change value of the bilateral iliac crest height, used as osseous landmarks, was measured in standing position and during walking. Bilateral iliac crest heights and their change values were measured in standing position and during the walking cycle to analyze the degree of pelvic coronal tilt in patients with different types of JIS.

A total of 73 JIS patients (54 patients in group A, and 19 patients in group B) and 34 non-JIS patients who met the inclusion and exclusion criteria were enrolled. In group A, 61.1%(33/54) of patients showed a "reasonable" relationship between the higher side of the iliac ridge and the convex side of the spine (the iliac ridge of the convex side of the lumbar spine/thoracolumbar spine was lower than that of the concave side), and 38.2%(13/34) of non-JIS patients showed a "reasonable" relationship between the higher side of the iliac ridge and the convex side of the spine (the iliac ridge of the convex side of the lumbar spine/thoracolumbar spine was at the same height as that of the concave side). The difference was statistically significant(P=0.036). The proportion of "reasonable" relationship in group B was not significantly different from that in non-JIS patients(26.3% vs. 38.2%, P=0.380). In group A, there were statistically significant differences in iliac crest height changes on both sides during the whole gait cycle (including minimum, maximum, minimum and maximum of the supporting phase) (all P < 0.05), and the iliac crest height changes on the convex side of lumbar spine were significantly higher than those on the concave side (all P < 0.05). However, there was no significant difference in bilateral iliac crest height between non-JIS patients and JIS patients in group B during the whole gait cycle(all P > 0.05).

In JIS patients with lumbar or thoracolumbar scoliosis, the iliac crest height of the lumbar scoliosis was lower than that of the concave side in standing position, and therefore, the tilt degree of pelvis obliquity should be increased to maintain bilateral balance during walking.