High-Risk Osteoporotic Vertebral Fractures for Pseudarthrosis Causing Painful Elderly Kyphosis

Purpose: Vertebral fracture is a common problem in the elderly population with osteoporosis. Progressive collapse and pseudarthrosis following osteoporotic vertebral fractures is occasionally encountered and causes painful kyphosis with/without neurological problems. The purpose of this study is to clarify high-risk fractures for osteoporotic vertebral pseudarthrosis causing painful elderly kyphosis.

Methods: One hundred-one patients with osteoporotic vertebral fractures who underwent conservative treatment were followed a minimum of two years. Following points were assessed as risk factors for osteoporotic vertebral pseudarthrosis: age; gender; treatment periods; causes, types and severity of initial vertebral fractures; and bone mineral density. Multivariate logistic regression model was employed for risk factor analysis.

Results: Incidence of osteoporotic vertebral pseudarthrosis was 13.9% (14/101 patients). Vacuum cleft within fractured vertebral body, intravertebral instability on lateral flexion-extension X-rays and progressive kyphotic deformity was observed in all 14 patients. High-risk fractures for vertebral pseudarthrosis were determined as follows: those caused by extremely minor injury events such as twisting the trunk or lifting heavy objects (odds ratio [OR]: 26.7, p=0.010); those in more aged population (OR/10 years: 12.0, p=0.012); and those with middle column involvement (OR: 9.7, p=0.038). The other factors such as severity of initial injuries were proved to be insignificant. Predicted probability [p] of vertebral pseudarthrosis was calculated by following equation: p=exp lð/(1+exp lð) [lð=2.801x +0.129x + 1.771x - 13.145: x =injury events, x =ages at initial injury, x =middle column involvement]. An example of vertebral fractures with extremely high-risk ([p] is around 90%) for pseudarthrosis was those with middle column involvement in 80 year-old patients who sustained injuries by twisting their trunks.

Conclusions: Osteoporotic vertebral pseudarthrosis is becoming a serious problem of today’s aging society because that causes painful kyphosis with/without neurological involvement. Although this condition frequently needs spinal reconstruction, many patients are intolerable for such major surgery because of poor medical status and severe osteoporosis. Therefore, prevention is essential for successful management of osteoporotic vertebral fractures in the elderly population. Estimate of high-risk fracture allows early selection of patients who are candidate for adequate and less invasive initial treatment such as kyphoplasty for osteoporotic vertebral fractures.