Preventing Distal Junctional Kyphosis by Applying the Stable Sagittal Vertebra Concept to Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis

Joshua Yang, Lindsay M. Andras, Alexander M. Broom, Nicholas R. Gonsalves, Kody K. Barrett, Andrew G. Georgiadis, John M. Flynn, Vernon T. Tolo, David L. Skaggs

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Study Design Multicenter retrospective review. Objective To assess the effectiveness of using the stable sagittal vertebra (SSV) for selecting the lowest instrumented vertebrae (LIV) to prevent distal junctional kyphosis (DJK) in selective thoracic fusions. Summary of Background Data Cho et al. reported that including the SSV in a fusion decreased the rate of DJK in thoracic hyperkyphosis. Methods A retrospective review was performed of patients from two pediatric hospitals with adolescent idiopathic scoliosis who underwent selective posterior thoracic fusion with the LIV at L2 or above from 2000 to 2012. Patients with less than 2 years’ follow-up were excluded. The primary outcome measure was DJK, defined radiographically as ≥10° between the superior end plate of the LIV and the inferior end plate of the vertebra below on a standing lateral radiograph. We investigated the SSV, which was defined as the vertebral level at which 50% of the vertebral body was in front of the posterior sacral vertical line (PSVL) on a standing lateral radiograph. This particular definition was referred to as SSV. Results A total of 113 patients met the inclusion criteria. Mean age was 14.4 years. Mean Cobb angle was 58°. The overall rate of DJK was 7% (8/113). When the LIV was superior to SSV, the rate of DJK was 17% (8/46) versus 0% (0/67) when the LIV was at or inferior to SSV (p=.01). The rates of DJK for patients with the LIV one, two, and three levels above SSV were 17% (4/24), 7% (1/14), and 43% (3/7), respectively. There was no significant association between preoperative or postoperative maximum kyphosis, thoracic kyphosis, thoracolumbar kyphosis, pelvic incidence, sagittal balance or coronal balance, and development of DJK. Conclusion Although LIV selection is complex, choosing the LIV at or below the SSV is a simple rule that minimizes the risk of DJK. Level of Evidence Level IV.

Original languageEnglish (US)
Pages (from-to)38-42
Number of pages5
JournalSpine Deformity
Volume6
Issue number1
DOIs
StatePublished - Jan 2018
Externally publishedYes

Keywords

  • Adolescent idiopathic scoliosis
  • Distal junctional kyphosis
  • Scoliosis
  • Stable sagittal vertebra

PubMed: MeSH publication types

  • Journal Article
  • Multicenter Study

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