NuVasive Publication: Efficacy of Synthetic Putty in Lumbar Fusion

Surgeons performing lumbar fusion surgery in an operating room.

Medical device company NuVasive, Inc. (Nasdaq: NUVA), based in San Diego, California, has announced a publication in the journal Spine demonstrating the efficacy of their synthetic bioactive putty as a bone graft substitute in posterolateral lumbar fusion, a widely-performed lower-spine surgery intended to stabilize the vertebral column. The surgery involves the restoration of normal spacing between two or more vertebrae via the insertion of a metal cage into the space between the vertebrae, and is intended to reduce pressure on highly painful pinched nerves.

The efficacy of a spinal fusion surgery depends not only on the removal of pain-causing structures by the surgeon, including herniated discs, tumors, or bone spurs, but also the stimulation of bone growth and healing between the linked vertebrae by the insertion of bone graft or another substance into the metal cage. Historically, bone graft needed to be harvested from the pelvis of the patient, extending the duration of the surgical procedure and leading to higher levels of pain during the recovery period after surgery. Today, in addition to bone derived from the pelvis, surgeons may use bone recycled from the site of the spinal fusion (autograft), bone harvested from a cadaver (allograft), or synthetic bone grafts including demineralized bone matrices (DBMs), bone morphogenetic proteins (BMPs), and synthetic bone (“ceramics”), which are often composed of calcium or phosphate and share many qualities with autograft bone. The NuVasive putty falls into the synthetic bone category.

President of NuVasive Matt Link stated, “A study of this quality immediately differentiates Attrax™ Putty from other biologics on the market. Attrax™ has proven the critical role surface optimization plays in the effectiveness of bone grafting technology, and underscores the NuVasive approach to developing innovative solutions which deliver positive clinical outcomes for surgeons and their patients.”

The randomized trial (NCT01982045), which involved 100 patients treated at four Dutch hospitals, evaluated the efficacy and safety of NuVasive’s putty versus that of autograft bone for supporting the fusion of linked vertebrae in the first year following surgery. During the treatment of each patient, NuVasive’s putty was applied to one side of the spine, chosen at random, and autograft bone material to the other, such that each patient received both putty and autograft bone and served as their own control. The degree of spinal fusion was determined by CT scan at one year post-procedure and demonstrated a 55% fusion rate for the putty-treated side and a 52% fusion rate for the autograft-treated side. The overall rate of spinal fusion was 71%.

The safety of the putty was assessed based upon the incidence of adverse events. While adverse events such as wound complications and serious adverse events including surgical site infection, screw malpositioning, cage dislocation, and persistent leakage of cereberospinal fluid occurred among patients in the cohort during the first year following surgery, the authors stated that the adverse events could not be directly related to the synthetic putty. According to the press release, “Attrax™ Putty alone successfully demonstrated non-inferior fusion performance compared to autograft in instrumented PLF.”

Associate Professor of Neurological Surgery and Orthopedic Surgery at Northwestern Memorial Hospital Dr. Tyler Koski stated, “With increased focus on value-based medicine, surgeons and hospitals seek improved evidence when choosing a biologic for spinal fusion. Most data for bone graft materials is of lower quality and supports their use as bone graft extenders combined with autograft. The fact that Attrax™ Putty by itself demonstrates non-inferiority to autograft, the gold standard for bone grafts, speaks to the power of its unique surface technology, and with this study, I’m better informed in my clinical decision-making.” Approximately 500,000 spinal fusions are performed in the United States every year.

According to NuVasive’s press release, “Attrax™ Putty is a synthetic, bioactive and osteoconductive bone void filler for the repair of bone defects. This proprietary, advanced biomaterial features a surface microarchitecture which provides an instructive environment for bone formation without added cells or growth factors. The moldable graft material is resorbed and replaced by bone during the healing process.” NuVasive has received 510(k) clearance by the United States Food and Drug Administration (FDA) for the “expanded use of Attrax™ Putty without autograft.”

Lehr M, Oner C, Delawi D, et al. (2020) Efficacy of a Standalone Microporous Ceramic vs. Autograft in Instrumented Posterolateral Spinal Fusion; a Multicenter, Randomized, Intra-patient Controlled, Non-inferiority Trial. Spine. DOI: 10.1097/BRS.0000000000003440