Wednesday, September 26, 2018 1:00 PM – 2:00 PM Spinal Trauma: 55. Aggravation of spinal cord compromise following new osteoporotic vertebral compression fracture prevented by teriparatide in patients with surgical contraindications

Abstract

BACKGROUND CONTEXT Osteoporotic fractures occur frequently in people over 50 years of age, with prevalence of 40%–50% in women and 13%–22% in men, among which osteoporotic vertebral compression fracture (OVCF) is the most common type. Although a large percentage of OVCFs are stable, the unstable OVCFs are not rare. Compared with the stable OVCFs, the unstable OVCFs could associate with neurological deficits and lead to higher morbidity and mortality. The unstable OVCFs usually are not candidates for cement-augmentation treatment, and the neurological deficits may aggravate after the traditional nonoperative treatment. Open surgery, which decompresses the spinal cord and stabilizes the fractured vertebrae by implanted instruments, is a potential option for the unstable OVCF to prevent further spinal cord compromise. However, if they have severe bone fragility or comorbid medical problems, decompression and instrument implantation surgeries are contraindicated. Teriparatide (Forteo, Eli Lilly and Co. Indianapolis, IN, USA) is the first bone anabolic drug approved by the US Food and Drug Administration for reducing the incidence of osteoporotic fracture. Recently, teriparatide has been shown to produce significant improvement of bone strength by improving bone turnover and bone mineral density (BMD). Lately, Park et al have applied teriparatide in treatment of the stable OVCF and found that short-term teriparatide treatment could decrease the progression of the fractured vertebral body collapse. In the present study, patients with neurological deficits following new unstable OVCF and with surgical contraindications were randomized into two groups receiving teriparatide/alendronate. We evaluated whether teriparatide can prevent the further fractured vertebral body collapse and prevent aggravation of spinal cord compromise in unstable OVCF. We hypothesized that conservative treatment with teriparatide would improve bone turnover parameters and BMD to strengthen the fractured vertebrae to be stabilized, as well as prevent aggravation of the spinal cord compromise. PURPOSE This study compared the preventive effects of teriparatide and alendronate on aggravation of spinal cord compromise following new unstable -OVCF- in patients with surgical contraindications. STUDY DESIGN/SETTING This was a 12-month, randomized, open-label study of teriparatide versus alendronate in 49 patients with new unstable OVCF and surgical contraindications. Neurological function was evaluated using modified Japanese Orthopedic Association (mJOA) score (11-point scale, the maximum score of 11 implies normalcy). Visual analog scale (VAS) scores, kyphotic angles, anterior-border heights and diameters of the spinal canal of the fractured vertebrae, any incident of new OVCFs (onset of OVCF during follow-up), spine bone mineral density (BMD), and serum markers of bone resorption and bone formation were also examined at baseline and 1, 3, 6, and 12 months after initiation of the medication regimen. PATIENT SAMPLE This was a 12-month, open-label, randomized controlled trial, conducted at our center, which compared the effects of teriparatide (Forteo, Eli Lilly, Indianapolis, IN, USA) and alendronate (Fosamax, Merck & Co., Kenilworth, NJ, USA) on patients with neurological deficits following new unstable OVCF and with surgical contraindications. From September 2012 to August 2014, we prospectively selected inpatients and outpatients who presented to our center with osteoporosis and new OVCF between T1 and L1. Inclusion criteria were female sex, age 60-80 years, new fracture within 3 weeks, single-level fracture without burst component, associated neurological deficit, L2–L4 BMD Tscore ≤−2.5, severe bone fragility (low BMD, ie, OUTCOME MEASURES Statistical analysis was performed using SPSS Statistics for Windows, Version 17.0 (SPSS Inc., Chicago, IL, USA). Results are presented as mean ± standard deviation. Depending on the normality of the data, the independent sample t test and Mann-Whitney U test were used to compare parameters between the two groups, while a paired t test was performed to analyze intra-group differences. Significance was accepted for a P value of RESULTS At 12 months, mean mJOA score had improved in the teriparatide group and decreased in the alendronate group. Mean concentrations of bone formation and bone resorption biomarkers, mean spine BMD, and mean anterior-border height and spinal canal diameter of the fractured vertebrae were significantly greater in the teriparatide group than in the alendronate group. Mean VAS score, mean kyphotic angle of the fractured vertebrae, and incidence of new OVCFs were significantly smaller in the teriparatide group than in the alendronate group. CONCLUSIONS In patients with neurological deficits following new unstable OVCF and with surgical contraindications, teriparatide was better than alendronate at improving the BMD and the bone turnover parameters, as well as preventing aggravation of spinal cord compromise. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.