Relative pelvic version displays persistent compensatory measures with normalised sagittal vertical axis after deformity correction.

Cawley D. T., Boissiere L., Yilgor C., Larrieu D., Fujishiro T., Kieser D., ...More

Spine deformity, vol.9, pp.1449-1456, 2021 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 9
  • Publication Date: 2021
  • Doi Number: 10.1007/s43390-021-00345-z
  • Journal Name: Spine deformity
  • Page Numbers: pp.1449-1456
  • Keywords: Adult spinal deformity, Relative pelvic version, Sacral slope, Pelvic tilt, Spino-pelvic, Fusion, Sagittal vertical axis, Alignment, Kyphosis, Lumbar lordosis, PROXIMAL JUNCTIONAL KYPHOSIS, RADIOGRAPHIC PARAMETERS, ADULT, CLASSIFICATION, ALIGNMENT, SPINE, TILT
  • Acibadem Mehmet Ali Aydinlar University Affiliated: Yes


Purpose A normal sagittal vertical axis (SVA) after spinal deformity correction can yield mechanical complications of up to 30%. Post-operative compensatory pelvic orientation can produce a normal SVA. We assess relative pelvic version (RPV), an individualised measure, for persistent post-operative compensatory measures. Methods Adult spinal deformity (ASD) patients who were treated operatively, with a normal SVA (< +/- 50 mm) at 6-week follow-up were included, who were then followed-up after 2 years. These only included patients with fusion of > 4 vertebrae extending to L5 or below. Six-week subgroups were made regarding pelvis orientation, relative pelvic version (RPV: anteversion, aligned, moderate or severe retroversion) with analysis of patient-related outcome measures (PROMs), complications and spino-pelvic sagittal parameters. Results At 6 weeks, 140 patients met the inclusion criteria, 5 (3.6%) patients had anteversion, 59 (42.1%) were aligned, 60 (42.9%) had moderate retroversion and 16 (11.4%) patients had severe retroversion. Follow-up after 2 years demonstrated increased RPV in all groups except the severe RPV group who were more likely to develop SVA > 50 mm. Complications occurred in all groups. Significant 2-year differences were observed between moderate and severe RPV for back pain and PROMs but not between other RPV groups. Conclusion Adult spinal deformity patients with a normal SVA after spino-pelvic instrumentation carry a significant risk of retroversion progression post-operatively, followed by increased positive sagittal balance. Relative pelvic version (RPV) measurements when categorised into anteversion, aligned, moderate retroversion and severe retroversion at 6 weeks were predictive of PROMs at 2 years.