Distal Fusion Level Selection in Scheuermann’s Kyphosis: A Comparison of Lordotic Disc Segment Versus the Sagittal Stable Vertebrae

Abstract

Study Design:Retrospective study.Objective:To compare 2 methods of selecting the lowest instrumented vertebra (LIV) on the rates of revision surgery for distal junctional kyphosis (DJK) following treatment for Scheuermann’s kyphosis (SK).Methods:A retrospective review of patients who have undergone surgical treatment for SK was performed. Forty-four patients were divided into 2 groups based on intervention: Group 1 (n = 26) included patients who had an LIV distal to or at the sagittal stable vertebrae (SSV), and Group 2 (n = 18) included patients who had an LIV proximal to the SSV. For each group, demographic, radiographic, and revision surgery data was analyzed.Results:The average follow-up was 3.1 years. There were no differences among demographic variables between the groups. Preoperative and postoperative thoracic kyphosis, lumbar lordosis, and sagittal balance were not different between groups. Postoperatively, Group 1 demonstrated a significantly greater average lordotic disc angle below the LIV compared with Group 2 (Group 1, −6.2 ± 4.3° vs Group 2, −2.9 ± 5.8°; P = .02). In a subgroup analysis, extending fusions to the sagittal stable vertebra rather than the first lordotic disc resulted in fewer distal LIV complications necessitating revision surgery compared with fusing short of the SSV (5% vs 36.3%, P = .04).Conclusion:The SSV method may reduce complications secondary to distal junctional failure, but at the expense of incorporating additional motion segments in a typically young population.

The surgical management of scheurmann’s kyphosis: Efficacy and safety of a low density posterior pedicle screw construct

“…The upper end vertebra (UEV) 34 is commonly the first level to be instrumented, while some authors propose going one level higher. Some studies advocate halting fixation one level below the first lordotic disc (FLD) for the distal instrumented vertebra (DIV), while others recommend including the sagittal stable vertebra (SSV) 3,[35][36][37][38][39] but in our opinion , we recommend the second thoracic to be the upper instrumented vertebra (UIV) and SSV to be the lower instrumented vertebrae( LIV) , we use these levels in all our SK cases and we didn't face any PJK or DJK in postoperative follow-up period.…”

Radiographic benefit of incorporating the inflection between the cervical and thoracic curves in fusion constructs for surgical cervical deformity patients

“…The consequences of end level selection can be dramatic, with previous research highlighting a potential connection between the inappropriate selection of the lower-most instrumented vertebrae and incidence of DJK. [ 23 ] A number of studies suggest that ending posterior fusion constructs at C7 (as opposed to T1) results in inferior postoperative cervical sagittal alignment, and is associated with an increased rate of surgical revision. [ 24 25 ] Our study did not show a difference in the rate of DJK between patients whose cervicothoracic inflection points were included in surgery and patients whose inflection points were not; however, it did show superior postoperative alignment outcomes for those with inflection points included in the fusion construct.…”

Scheuermann's kyphosis: update on pathophysiology and surgical treatment

“…According to Cho et al , choosing the SSV instead of the FLD decreases the incidence of DJK ( 61 ). Patients who were fused at or below the SSV using posterior-only construct were found to have markedly greater lordotic disk angles below the LIV and lower revision surgery rates for DJK compared to patients who had an LIV proximal to the SSV (5% vs 36.3%) at the expense of incorporating additional motion segments ( 62 ). The choice of the LIV is important to decrease the occurrence of DJK.…”