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Aakash Agarwal, Ph.D., Director of Research and Development at Spinal Balance and an adjunct professor at the University of Toledo, is focused on reducing surgical site infection (SSI) in orthopedic procedures. To that end, Spinal Balance has developed the Libra® pedicle screw system, which utilizes a touch-free patent-pending locking mechanism and an impermeable guard designed to eliminate contaminants from an implant’s surface.
“The likelihood of post-operative infection depends on three factors,” Dr. Agarwal explained. “The dose of bacteria left from surgery, the virulence of bacteria and the patient’s immune response (natural or boosted by antibiotics) at the surgical site. One meta-analysis based on varied practices showed a 3.8% infection rate. It is in every patient’s best interest to be exposed to the least amount of bacterial dose during surgery.”
To learn more about his research into SSI and Spinal Balance’s products, we posed several questions to Dr. Agarwal.
What has your research focused on and what have you discovered?
Dr. Agarwal: We seek to identify solutions to mitigate the presence of both non-microbial (outside the O.R.) and microbial (inside the O.R.) foreign body contaminants on orthopedic implants. This can be extended to instruments, but as implants remain permanently in the body, they are our priority.
Implants undergo repeated bulk-cleaning with dirty instruments in the O.R., leading to residue buildup at the interfaces and surfaces. This goes unnoticed by a hospital’s Sterile Processing Department; there is no way to inspect each of the hundreds of implants at microscopic levels and at interfaces not directly visible. This type of contamination can only be avoided by using single-use, pre-sterilized implants. The second way that implants become contaminated is intraoperatively. Sterile implants are touched by a scrub tech with soiled gloves when loading onto an insertion device. Implants then remain exposed on the table. A multi-center trial has shown that by the time it is inserted in the patient, an implant can harbor up to 10e7 bacterial colony forming units.
We also had a study group using an impermeable sterile-guard around a device, which shielded the implants intraoperatively until patient insertion. The result was zero contamination. Thus, the impermeable guard is an effective precautionary measure against SSI, or subclinical and chronic sepsis, leading to screw loosening and pain.
How exactly do your products work?
Dr. Agarwal: All Spinal Balance implants come in easy-to-store and immediately identifiable individual, single-use sterile tubes, reducing our inventory footprint at the hospital by half. This storage method ensures they are always surgery-ready, and no plan-ahead processes for emergency reprocessing and steam sterilization are involved. Second, any seasoned O.R. staff will tell you they get stressed opening traditional sterile packaging, such as pouches and cartons. They prefer the ergonomics and intuitiveness of tubes and caps; twist and it is accessible.
All Spinal Balance implants have a functional sheath or guard. A hold-and-load insertion device was designed so that all intraoperative tasks can be completed without exposure to bloody gloves, surfaces or open-air flow. So, O.R. staff can mix bone substitute or graft into the implants, or keep the implants on the working table, before insertion and they remain pristine and free of bacteria.
What has been the response from surgeons and industry?
Dr. Agarwal: Many spine surgeons, including several at UMass Memorial Medical Center in Boston, are aware of this problem and have been trying to address it. At NASS 2018, Dr. Richard Guyer, co-founder of Texas Back Institute, expressed his deep concern and how crucial [addressing SSI] is. In short, surgeons appreciate what we are doing and are enthusiastic about it, because they value aseptic practices as the perquisite of any surgical philosophy.
Industry is moving towards providing implants in sterile tubes to avoid risky and repeated reprocessing, the need for extra and backup inventory and challenges such as storage and identification. More than $6 billion worth of pedicle screws are stored in U.S. hospitals. Half of the stored inventory capital from that could be freed up by packaging pedicle screws in individual sterile tubes.
What are the next steps for your company and your research?
Dr. Agarwal: From a research standpoint, we continue to design both outer tubes and functional guards and sheaths for pedicle screws, interbody cages, hip and knee joint replacement components, etc. Future endeavors include a clinical trial addressing touching autografts during morselization and packing into the intervertebral cages.
Commercially, Spinal Balance is getting involved in strategic licensing partnerships to bring our products to more patients.
