Patterns of coronal curve changes in forward bending posture: a 3D ultrasound study of adolescent idiopathic scoliosis patients

Wei Wei Jiang, Connie Lok Kan Cheng, Jason Pui Yin Cheung, Dino Samartzis, Kelly Ka Lee Lai, Michael Kai Tsun To, Yong Ping Zheng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

15 Citations (Scopus)


Purpose: The Adam’s forward bending test is the most commonly used approach to assess the spine deformity in adolescent idiopathic scoliosis (AIS) patients. However, there are noticeable differences in the hump appearance from standing to forward bending. This phenomenon has yet to be understood due to limitations of conventional radiographs. This study aimed to investigate effects of postural change in the spine deformity in the coronal plane of AIS patients using a 3D ultrasound imaging system. Methods: This was a prospective study that recruited 72 AIS patients at a single institute. All patients were scanned twice in the sitting and sitting forward bending postures. A coronal ultrasound image showing the spinal curvature was generated after each scan and the spinous process angle (SPA) representing the deformity was manually measured from it. Correlation of SPAs under sitting and sitting forward bending postures was analyzed. Results: In the comparison test, it was noted that there were three types of spine profile alternation after the postural change. In types I and II, the SPA angle numbers were the same before and after forward bending and only SPA values changed. In type III, the two curvatures were changed to one curvature in the forward bending posture. Moderate correlation was observed between the angles obtained in the two postures (r = 0.55, p < 0.001). Conclusions: Spine deformities of AIS patients vary with different postures. The patterns of changes in sitting and sitting forward bending postures are highly subject dependent. Graphical abstract: These slides can be retrieved under Electronic Supplementary Material.[Figure not available: see fulltext.].

Original languageEnglish
Pages (from-to)2139-2147
Number of pages9
JournalEuropean Spine Journal
Issue number9
Publication statusPublished - 1 Sept 2018


  • 3D ultrasound
  • AIS
  • Forward bending
  • Scoliosis
  • Trunk posture

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine


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