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.

To evaluate the severity and features of pelvic coronal plane tilt in individuals with adolescent idiopathic scoliosis (AIS) who had lumbar curvature during the gait cycle.

AIS patients with lumbar curvature and patients with microcurvature (Cobb Angle less than 10 degrees) treated in Peking Union Medical College Hospital from September 2020 to February 2023 were retrospectively included. According to PUMC conservative classification system and Spinal Full-length Standing X-ray, AIS patients with lumbar curvature were enrolled. The bilateral iliac crest was used as the bony marker of the pelvic coronal surface, and the bilateral iliac crest height and its changes were measured during the standing position and walking cycle, so as to evaluate the degree of pelvic coronal tilt in AIS patients with lumbar curvature.

A total of 209 AIS patients with lumbar curvature and 36 patients with microcurvature who met the inclusion and exclusion criteria were enrolled. The proportion of AIS patients with lumbar curvature who had a "congruent" relationship between the higher iliac crest and the convex side of the spine in standing position (iliac crest lower on the convex side than on the concave side) was significantly higher in AIS patients with lumbar curvature than patients with microcurvature(58.9% vs. 30.6%, P=0.002). AIS patients with lumbar curvature had statistically different bilateral iliac crest height change values throughout the gait cycle (including minimum, maximum, swing phase minimum, and swing phase maximum) (all P < 0.001), and the iliac crest height change values on the convex side were significantly higher than those on the concave side (all P < 0.05), whereas the patients with microcurvature did not have any statistically significant bilateral iliac crest height change values throughout the gait cycle (all P > 0.05).

The height of the iliac crest on the convex side of the lumbar spine is lower than that on the concave side in the standing position of AIS patients with lumbar curvature, and the value of the change of the iliac crest on the convex side of the pelvis is greater than that on the concave side in walking to maintain the balance of the body, which may provide a new direction for the intervention in the clinical rehabilitation treatment of AIS patients with lumbar curvature.