The Spine Journal recently published an analysis of patients who received bone morphogenetic protein in thoracolumbar spine surgery from 2006 to 2010.
BMP use in the thoracolumbar spine remains controversial and many in the field question its benefits and risks. The researchers examined a matched cohort of 52,259 patients. Patients without BMP treatment were matched two-to-one to patients receiving intraoperative BMP. The researchers used the MarketScan database for their analysis.
The article was funded by a $200,000 award from the Orthopedics Research and Education Foundation. The article authors were Anand Veeravagu, MD, Tyler Cole, BS, Bowen Jiang, MD, John K. Ratliff, MD, Risha Gidwani, DrPH.
Here are five things to know about the findings on intraoperative BMP use for thoracolumbar procedures:
1. Patients who received BMP underwent fewer re-fusions, decompressions, posterior revisions, anterior revisions or any revision procedure. A separate study examining fusion rates for BMP found the reoperation for nonunion rates were similar among BMP and non-BMP groups at six months, one year and two years. The study included 5,456 cases and found the reoperation rates for nonunion were:
• Six months: 13 percent nonunion in the non-BMP group; 16 percent nonunion in the BMP group
• One year: 21 percent in the non-BMP group; 37 percent in the BMP group
• Two years: 22 percent in the non-BMP group; 30 percent in the BMP group
2. BMP was not associated with postoperative cancer development after adjusting comorbidities, demographics and levels of procedure. "Although no BMP-associated increased risk of malignancy was found, lack of long-term follow-up precludes detection of between-group differences in malignancies and other rare events that may not appear until later," concluded the authors.
3. There was an increased risk of complications for patients who underwent multi-level procedures that received BMP at 30 days postoperatively. The researchers found 15.8 percent of the BMP patients had complications, compared to 14.9 percent in the non-BMP group. The 30-day complications in multilevel procedures associated with BMP use include dysrhythmia and delirium.
A second study published in 2011 examines almost 12,000 patients from around the country who underwent spinal fusions between 2004 and 2007. The study, led by the Scoliosis Research Society, found most problems occurred with BMP during cervical spine fusions. Other spinal fusions with and without BMP had equal complications, and no difference in mortality. However, patients in the BMP group were twice as likely to need revision as the non-BMP group.
4. BMP use in both single and multilevel procedures as associated with a new diagnosis of chronic pain. A separate study of 114 patients undergoing transforaminal lumbar interbody fusion and anterior lumbar interbody fusions found two of the ALIF patients had severe back pain with marked vertebral body inflammation seen on an MRI. The response occurred within two weeks of surgery, but was settled with conservative treatment.
Among the TLIF patients, six experienced severe back pain and recurrence of leg pain; four of the patients had fluid cyst formation within the spinal canal, as seen on the MRI, and the remaining two reported a diffuse inflammatory response in the region of the posterior aspect of the cage and adjacent epidural space but without discrete cyst formation.
"The incidence of an exaggerated inflammatory response with BMP in the lumbar spine may be under-recognized," the study authors concluded.
5. There was a negative association between infection in single level procedures and BMP use. Additionally, BMP use was negatively associated with wound dehiscence in multiple level procedures. Last week, GlobalData released a report updating projections for growth in the spinal fusion market. Previously the analysts at GlobalData expected spinal fusions would grow at a 10 percent compound annual growth rate through 2020, but has reduced that projection to a 5 percent growth over the next six years.