How does congenital cervicothoracic scoliosis bring about early trunk tilt and coronal imbalance during curve progression: a radiographic analysis to dissect the mechanism of proximal takeoff phenomenon

Eur Spine J. 2023 Oct;32(10):3591-3598. doi: 10.1007/s00586-023-07884-1. Epub 2023 Aug 17.

Abstract

Purpose: To dissect the mechanism of how congenital cervicothoracic scoliosis (CTS) drive the occurrence of early trunk tilt, namely proximal takeoff phenomenon (PTO) during curve progression.

Methods: CTS patients were stratified into case and control groups according to the presence of PTO. The radiographic deformity parameters of head-neck-shoulder complex were measured and compared between the two groups. The main risk factors for PTO were identified through multiple linear regression analysis.

Results: 16 CTS patients with PTO were recruited, and the non-PTO group consisted of 19 CTS patients without PTO. The average Cobb angle was 64.9 ± 19.8° in PTO group and 57.7 ± 21.9° in control group (p > 0.05). Significant difference could be observed for head shift, neck tilt, trunk inclination, apex-C7 deformity angular ratio (DAR), apex translation ratio, C6 tilt, clavicle angle (CA), radiographic shoulder height (RSH), head-neck translation and coronal balance distance (CBD) (All p < 0.05) but not head tilt (p > 0.05). Multiple linear regression analysis revealed that head shift, but not neck tilt correlated significantly with the severity of trunk inclination (β = 0.106, p = 0.003), while apex-C7 DAR and apex translation ratio were the two factors contributing significantly to the severity of head shift (β = 0.620, p = 0.020; β = - 0.371, p = 0.004).

Conclusions: Development and progression of head shift rather than neck tilt is a significant causative factor initiating the occurrence of trunk tilt and proximal takeoff in CTS. A higher apex-C7 DAR representing a short angular upper hemi curve and a lower apex translation ratio representing poor proximal coronal compensation are key risk factors predisposing to head shift.

Keywords: Cervicothoracic scoliosis; Coronal imbalance; Head shift; Proximal spinal takeoff; Torticollis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Humans
  • Neck
  • Retrospective Studies
  • Scoliosis* / diagnostic imaging
  • Scoliosis* / etiology
  • Spinal Fusion* / adverse effects
  • Thoracic Vertebrae / diagnostic imaging
  • Thoracic Vertebrae / surgery

Substances

  • selenium disulfide