Kyphosis progression after balloon kyphoplasty compared with conservative treatment

Study Design: Retrospective cohort study (level of evidence: 4). Purpose: To demonstrate the effects of balloon kyphoplasty (BKP) on prevention of kyphosis progression. OverView of Literature: Kyphoplasty can correct local kyphosis (fractured vertebra), but its efficacy is attenuated by adjacent fracture and/or disc height reduction with endplate damage. With these attenuating factors incorporated, a comparison between BKP and conservative treatment is necessary to verify the effect of BKP on kyphosis correction. Methods: This study retrospectively analyzed 129 patients treated conservatively and 95 treated with BKP in our institution. The rate of new adjacent fracture occurrence was determined using Kaplan-Meier analysis. We examined the progression of local kyphosis in patients who underwent lateral X-ray after 1 year. Local kyphosis was measured as an angle between higher end plate of the vertebra above and lower end plate of the vertebra below the fractured vertebra. The comparison included 45 patients treated conservatively and 58 treated with BKP Results: The incidence of new adjacent fracture at 1 year was 7.3% in the conservative treatment group and 23.2% in the BKP group (p<0.001), while the progression of local kyphosis at 1 year was 5.7°±4.7° and 3.2°±4.6°, respectively (p=0.01). Relative to conservative treatment, local kyphosis did not progress after BKP, despite the higher incidence of adjacent fracture. Local kyphosis progressed in cases with adjacent fracture compared with those without adjacent fracture (6.0°±4.3° vs. 2.1°±4.3°, p=0.003), and fractured vertebral instability was found to be a risk factor for adjacent fracture in BKP. Conclusions: Compared with the conservative treatment, BKP suppressed the progression of local kyphosis. However, an adjacent fracture attenuated the BKP correction and was more frequently seen in patients with unstable vertebral fractures.