Medtronic announced the results of a retrospective claims-based data analysis suggesting that a patient group of over 65 years whose spinal fractures were treated with minimally invasive surgery had a higher survival rate up to four years after treatment than a patient group that did not have surgery. The evaluation is pending US FDA review of the claims.
The data further suggested that of the patient group treated with one of the two minimally invasive surgical procedures available, a sub-group treated with balloon kyphoplasty had higher survival rate up to four years after treatment than a sub-group that was treated with vertebroplasty.
During the evaluation period, which was jointly carried out by Exponent and Medtronic, Kyphon Balloon Kyphoplasty (Medtronic) was the only balloon kyphoplasty treatment for spinal fractures cleared by the FDA in the USA.
This first longitudinal, population-based comparison of mortality risk between operated and non-operated patient groups with spinal fractures and between balloon kyphoplasty and vertebroplasty patient sub-groups was published online recently in The Journal of Bone and Mineral Research.
In the evaluation, researchers looked at data from the US Medicare dataset including a population of one million patients that suffered vertebral compression fractures from 2005 through 2008. After inclusion criteria were applied, a population of 858,978 spinal fracture patients was analysed. The population included 119,253 or 13.9% treated with balloon kyphoplasty, 63,693 or 7.4% treated with vertebroplasty and the remaining treated only with non-surgical care such as pain medication, bed rest, physiotherapy or bracing.
Findings of the four year follow-up evaluation:
The patient group whose spinal fractures were treated surgically with either balloon kyphoplasty or vertebroplasty had a statistically significant higher adjusted survival rate of 60.8% compared to 50.0% for the patient group undergoing conservative or non-surgical care. The surgical group was 37% less likely to die than the non-surgical group.
The patient sub-group that received balloon kyphoplasty had a statistically significant higher survival rate of 62.8% compared to the 57.3% survival rate of the sub-group treated with vertebroplasty. The relative risk of mortality for the kyphoplasty sub-group was 23% lower than that for vertebroplasty sub-group.
The improved survivor rate of the group treated with minimally invasive surgery was confirmed by an analysis of a sub-group of these patients who were alive one year after their initial diagnosis of a spinal fracture. This group was 18% less likely to die by the end of the study than those in the non-surgical group. When separated by the type of surgery received, those in the balloon kyphoplasty group were 24% less likely to die by the end of the study, and those in the vertebroplasty group were 7% less likely to die.
Certain demographics such as gender, age and lower socio-economic status were found to be statistically significant mortality risk factors for patients with spinal fractures regardless of treatment method. Men had a higher mortality risk than women , those 75 and older had a higher mortality risk than those 65-69 , and those with lower socio-economic status based on Medicare buy-in status had a higher mortality risk than those with higher socio-economic status.
“We are very pleased that this evaluation suggested significantly improved survivorship in the patient sub-group whose vertebral compression fractures were treated with balloon kyphoplasty compared with vertebroplasty,” said Av Edidin, one of the evaluation’s authors and vice president, science and technology, for the Spinal and Biologics Division of Medtronic. “Our hope is that this evaluation will shed light on this important public health issue, open scientific discussion and lead to future studies on the reasons for the improved survivorship in patient groups treated surgically for spinal fractures compared with groups that received non-surgical treatment.”
While both balloon kyphoplasty and vertebroplasty are minimally invasive procedures to treat spinal fractures, the procedures are very different. Vertebroplasty only stabilises the fracture. Balloon kyphoplasty is designed to not only stabilise the fracture, but also attempts to correct vertebral body deformity with the inflation and removal of orthopaedic balloons prior to injection of a more viscous bone cement under low manual pressure.
Limitations
Due to its retrospective, observational nature, this evaluation did not and could not investigate causal relationships between surgical treatment, non-surgical treatment and improved patient survival. Also, while patients in the non-surgical treatment group had greater mortality rates than those in the surgical group, the evaluation did not look into the events that lead to their deaths.
