[Correlation analysis of Cobb angle and linear spinous process angle in adolescent idiopathic scoliosis]

To analyze the correlation between Cobb angle and spinous process angle (SPA) on X-ray film and body surface in patients with mild to moderate adolescent idiopathic scoliosis(AIS). To explore the possibility of linear SPA to assess scoliosis.

Retrospective study for correlation of Cobb angle and linear SPA on X-ray film. AIS patients treated and taken full spine anteroposterior X-ray from January 2019 to December 2021 were analyzed correlation of Cobb angle and linear SPA on X-ray film. Prospective study for correlation of Cobb angle and body linear SPA. AIS patients treated and taken full spine anteroposterior X-ray from December 1 to December 9 this year were analyzed correlation of Cobb angle and body linear SPA.

A total of 113 AIS patients with age an average of (14.02±2.16) years old(ranged from 10 to 18 years old) were recruited in retrospective study, involving 26 males and 87 females;there were 71 patients with mild AIS and 42 patients with moderate AIS. Cobb angle in AIS patients was significantly inversely associated with SPA(r=-0.564, P<0.001), the linear regression equation was:Cobb angle=169.444-0.878×SPA. Cobb angles in patients with mild scoliosis were significantly and inversely associated with SPA(r=-0.269, P=0.012), the linear regression equation was:Cobb angle=46.832-0.185×SPA. Cobb angles in patients with moderate scoliosis were also clearly correlated with SPA(r=-0.417, P=0.003), the linear regression equation was:Cobb angle=113.889-0.516×SPA. Thirty-eight patients were recruited in prospective study. The mean Cobb angle and body linear SPA were(18.70±6.98)°, ranged from 11.3° to 36.0° and (170.34±4.57)°, ranged from 162.1° to 177.7° respectively. There was significantly negative correlation(r=-0.651, P<0.001), the linear regression equation is:Cobb angle=187.91-0.99×SPA.

Linear SPA on X-ray film or on the body was significantly negatively correlated with Cobb angles, but the regression equation fits poorly, so it's not suitable for diagnosis of scoliosis;however, linear SPA is appropriate for self-controlled assessment of scoliotic therapy or for dynamic assessment of spinal flexibility.