INTRODUCTION: The osteoporotic vertebral body fractures (OVFs) represent a significant medical and socioeconomic burden. There is ongoing debate concerning the role of cement augmentation versus conservative management, but we are increasingly recognizing the longer-term effects of kyphotic vertebral alignment on functional outcomes, pain, and subsequent fracture rates. The purpose of this study was to determine the effect of timing of intervention with percutaneous balloon kyphoplasty (BKP) for OVF on clinical and radiographic outcomes.

PATIENTS AND METHODS: 101 patients (mean age, 76.8 years) who underwent BKP for OVF were analyzed. All patients underwent plain radiographs of the spine, MR imaging, and bone scan within 1 weeks of treatment. The inclusion criteria were as follows: (1) 0–90 % loss of vertebral body height on plain X-rays; (2) severe back pain associated with a single VCF refractory to analgesic medication; (3) pain score on a visual analog scale of five or higher; and (4) the affected vertebral body showing a confined high signal intensity on T2-weighted MR imaging, a diffuse low signal intensity on T2-weighted MR imaging [1], or a diffuse low signal intensity on T1-weighted MR imaging [2]. Patients with multiple myeloma, metastatic bone disease, radiculopathy, history of spinal surgery, or who had follow-up less than 6 months were excluded. Patients were divided into two groups based on timing of BKP: early (<4 weeks) or late (>4 weeks). Multiple factors were assessed preoperatively and throughout follow up and compared between groups using bivariate testing, including: focal kyphosis, subsequent vertebral fracture, and low back pain.

RESULTS: This was a retrospective sub-group analysis. There were 74 patients in the early group and 27 patients in the late group. There was no significant difference in preoperative bone density between groups. Mean follow-up was 1.2 years. Local kyphosis at final follow-up was significantly greater in the late group (-25.4°) than in the early group (-11.7°; p <0.001). There was no significant difference in local kyphosis between preoperative measurement and final follow-up in the early (p=0.741) or late cohort (p=0.794). Patients treated with early BKP demonstrated significantly better LBP scores (p <0.05) and a lower rate of subsequent vertebral fracture (p <0.05).

CONCLUSION: BKP is able to prevent progressive collapse and kyphosis after OVF, but not effectively restore alignment, and as a result, patients who undergo early BKP (<4 wks) demonstrate improved alignment, better LBP scores, and reduced rates of subsequent fracture at an average of 1.2 years following treatment.

REFERENCES:

[1] Tsujio T, et al.　Characteristic radiographic of magnetic resonance images of fresh osteoporotic vertebral fractures predicting potential risk for nonunion: a prospective multicenter study. Spine 361229-1235, 2011.

[2] Kanchiku T, et al. Usefulness of an early MRI-based classification system for predicting vertebral collapse and pseudoarthrosis after osteoporotic vertebral fractures. J Spinal Disord Tech 27: E61-65, 2014.