The Implications of Sacralized Transitional Vertebra on Spinal Alignment

Marc Khalifé; Claudio Vergari; Renaud Lafage; Jonathan Elysée; Mikael Finoco; Olivier Gille; Ayman Assi; Wafa Skalli; Virginie Lafage; Emmanuelle Ferrero

doi:10.1097/BRS.0000000000005187

The Implications of Sacralized Transitional Vertebra on Spinal Alignment

Spine (Phila Pa 1976). 2024 Oct 15. doi: 10.1097/BRS.0000000000005187. Online ahead of print.

Authors

Marc Khalifé^{1

2

3}, Claudio Vergari⁴, Renaud Lafage³, Jonathan Elysée³, Mikael Finoco^{1

2}, Olivier Gille⁵, Ayman Assi⁶, Wafa Skalli⁴, Virginie Lafage³, Emmanuelle Ferrero^{1

2}

Affiliations

¹ Department of Orthopedic Surgery, Hôpital Européen Georges Pompidou, Paris, France.
² Université Paris-Cité, Paris, France.
³ Department of Orthopedic Surgery, Northwell Health, Lenox Hill Hospital, New York City, NY, USA.
⁴ Arts et Métiers Institute of Technology, Université Sorbonne Paris-Nord, IBHGC - Institut de Biomécanique Humaine Georges Charpak, HESAM Université, Paris, France.
⁵ Orthopedic Surgery Department, Spine Unit, Pellegrin University Hospital, pl. Amélie Raba Léon, 33000 Bordeaux, France.
⁶ Faculty of Medicine, Saint-Joseph University, Beirut, Lebanon.

PMID: 39451150
DOI: 10.1097/BRS.0000000000005187

Abstract

Study design: Retrospective study of a multicentric prospective database.

Objective: This study aimed to determine, in a cohort of healthy volunteers, the impact of sacralized lumbo-sacral transitional vertebra (LSTV) on spinal alignment according to its grade, particularly regarding lumbar lordosis magnitude and distribution, and the implications for spinopelvic parameters measurement.

Summary of background data: There is little data regarding spinopelvic alignment assessment in LSTV patients.

Methods: This study included healthy volunteers with full-body stereoradiographs in free-standing position aged over 18. Castellvi grade, pelvic parameters (measured on S1 and L5), L1-S1 lumbar lordosis (LL) and segmental lordosis for each disc and vertebral body, thoracic kyphosis, cervical lordosis, lower limb, and global alignment parameters were assessed. Castellvi I and II were considered as Low-grade and Castellvi III and IV as High-grade LSTV. Alignment parameters between No-LSTV, Low- and High-grade LSTV were compared. Propensity score matching was used to match PI in No-LSTV and Low-grades. Spinopelvic parameters measured on S1 in No-LSTV group and on L5 in High-grade were compared.

Results: 713 subjects were included, of whom 23 Low-grades and 27 High-grades. Mean pelvic incidence was 51.0±11.0° and mean age was 37.5±16.2 years. LL distribution was different between groups, with an apex and inflexion point significantly higher in High-grade ( P<0.001 ). Kyphosis in the LSTV segment was compensated for by a steeper increase of LL above L5 in the High-grades. Low-grades and PI-matched No-LSTV presented similar alignment parameters. There were minor differences in parameters measured on S1 in No-LSTV and no L5 in High-grades.

Conclusion: Subjects with low-grade LSTV present similar alignment as PI-matched No-LSTV subjects, and S1 should be taken as reference to measure spinopelvic parameters. High-grade LSTV subjects have kyphotic L5-S1 segment with more cranial lumbar apex and thoracolumbar inflexion point. In these subjects, spinopelvic parameters should be measured on L5.