A study has identified several factors, including the use of BMP-2, that increase the risk of neurological issues in patients who underwent lateral lumbar interbody fusion (LLIF) with a retroperitoneal approach. BMP-2, or bone morphogenetic protein-2, is closely associated with Medtronic Infuse, a bone graft product that uses recombinant human BMP-2 (rhBMP-2).
Healio reports that Alexander Aichmair, MD, a spine research fellow at New York‘s Hospital for Special Surgery, and his colleagues conducted a study to find out what factors increased the risk for neurological deficits in LLIF patients and whether or not the effects were persistent or temporary. Current literature shows that neurological deficits occur anywhere between 0.7 and 23 percent of the time after an LLIF.
Aichmair’s study, which looked at 451 patients who underwent LLIF, found that “The level of fusion, multilevel lateral lumbar interbody fusion, female gender, as well as the use of bone morphogenetic protein-2 [BMP-2] were associated with a higher risk of developing a postoperative neurological deficit and pain,” The study included people with a degenerative spine and at least 6 months of follow-up postoperatively. None of the patients had a previous history of thoracolumbar spine surgery. The average age of the patients was 63 years at the time of surgery, and they were followed for an average of 15 months.
Aichmair said that the most frequently treated levels of the spine were L3-4 and L4-5. A total of 919 levels were treated amongst all the participants, averaging to two levels per patient.
The study found that the rate of motor deficits was 24.1 percent and the rate of sensory deficits was 17.3 percent at initial analysis. A number of other analyses were performed for subgroups throughout the study. Not including those who had neurological deficits preoperatively, the rates of motor and sensory deficits were 3.2 and 9.3 percent, respectively. For 87 patients followed for at least 18 months, reseachers looked at rates for persistent motor deficity (2.3%), sensory deficit (9.6%) and anterior thigh and groin pain (5.8%), which was presebt during the final follow-up visit.
Overall, BMP-2 use, being female, surgeon experience, the L2-3 level and multilevel surgery were identified as risk factors for neurological deficits and/or pain. The deficits are generally transient, and occur at high rates after surgery.
This study confirms previous research showing that BMP-2 is a risk factor for neurological deficits, Aichmair said. He cited previous work with colleagues, which compared LLIF patients with BMP-2 use to those with no BMP-2 use.
Medtronic Infuse is an artificial bone growth product that has become controversial due to reports that researchers paid by the company failed to report side effects in published studies. Infuse has also been linked to potentially deadly side effects such as swelling of the neck and throat when used off-label in the cervical spine. Complications associated with Infuse nerve injury, male sterility, cancer and excess bone growth.