Special Poster Session 50th International Society for the Study of the Lumbar Spine Annual Meeting 2024

INTRODUCTION

Osteoporotic vertebral fractures (OVF) have a good prognosis with conservative treatment. However, the subsequent fracture risk is higher immediately following an initial fragility fracture. Domino OVFs have been named for the chain reaction of acute OVFs within a short period of time and are assumed to be rapidly developing multiple OVFs over a few months. Recently, anabolic agents such as teriparatide and romosozmab may have prevention of poor prognosis after OVF. This study aimed to investigate the effects of anabolic agents on secondary domino OVF, bony union, and vertebral collapse.

METHODS

This study is a prospective multicenter cohort study conducted in eight hospitals. The inclusion criteria are as follows: 1) acute single OVF occurring within 3 weeks, 2) aged >60 years, 3) anabolic agents or bisphosphonate use, 4)12 months follow-up. A total of144 patients (age 79.3 years, 80% female) who had been treated with romosozumab (Romo) group in 27 patients, teriparatide (TPTD) in 62 patients, and bisphosphonate (BP) in 55 patients were included in the study. The selection of anti-osteoporosis medication was determined by the attending physician. The primary outcome was the incidence of secondary OVF at 3 and 12 months. The secondary outcomes were incidence of pseudoarthrosis, severe vertebral collapse (SQ grade 3), and bone mineral density (BMD) change at 12 months. Pseudoarthrosis was classified into stable and unstable types based on instability of more than 3 degrees and the presence of bridge formation to the adjacent vertebra. Statistical analysis was conducted using ANOVA tests, chi-squared tests, and the Turkey-Kramer test.

RESULTS

No significant difference was observed in the incidence of domino OVF at 3-months (Romo: 14.8%, TPTD: 8.1%, BP: 9.1%, p= 0.55) and at 3 to 12 months (Romo: 0%, TPTD: 3.2%, BP: 5.5%, p=0.29) among three groups (Figure 1). There were no significant differences in age, gender, BMI, hospitalization, and type of brace among the three groups. No significant difference was observed in the incidence of pseudarthrosis (Romo: 15%, TPTD: 17.7%, BP: 19.4%, p= 0.84). However, unstable pseudarthrosis was significantly higher (p=0.03) in the BP group (16.4%) than in the Romo group (5%) and TPTD group (4.7%) (Figure 2). Severe vertebral collapse tended to be higher (p=0.07) in the BP group (39%) than in the Romo group (19%) and TPTD group (25%). There was no significant difference in lumbar BMD change (Romo: 8.9%, TPTD: 8.1%, BP: 6.3%, p= 0.41), and toral hip BMD change (Romo: -1.2%, TPTD: -0.7%, BP: -2.7%, p= 0.31).

DISCUSSION

Anabolic agents did not significantly reduce subsequent domino OVF, but there was a trend toward decreased severe vertebral collapse in the TPTD and Romo groups and a significant reduction in unstable pseudoarthrosis.