In September, a Connecticut neurosurgeon became the second in the world to perform spine surgery with a newly approved patient-specific implant, which he believes can reduce complications and achieve superior outcomes over traditional implants.
The surgery was performed by Vijay Yanamadala, MD, system medical director of spinal quality and surgical optimization and director of spinal deformity surgery at Hartford (Conn.) Healthcare.
Dr. Yanamadala spoke to Becker's Spine Review about the benefits of patient-specific spinal implants, how surgeons work with the devicemaker to create each implant and how he sees the technology developing in the future.
Question: What benefits do patient-specific spine implants offer over traditional implants?
Dr. Yanamadala: The idea here is when we use interbody devices in the spine to do fusions, such as [transforaminal lumbar interbody fusion] or [anterior lumbar interbody fusion], oftentimes we're using standard implants that are preprinted and we're just fitting them into the patient's spine. What we know is that these interbody devices come with failed fusions, pseudoarthrosis with graft subsidence, and we think one of the reasons for this is the graft does not fit to the patient's spine.
Carlsmed now has FDA approval for these patient-specific interbody devices, which are based on HD CT scans of the patient's spine. Based on that data, we can generate a contoured interbody device. The company puts it through their artificial intelligence process, and I can then fine-tune it using a 3D model.
Q: Once you receive the implant, how do you modify it for the patient?
VY: The implant has to be adjusted to the asymmetrical goal. For example, I may need to asymmetrically adjust a patient's scoliosis, so I would need that implant to be adjusted accordingly, or I want to place the implant to one particular side because the patient's symptoms are more to the left or the right. Those are the nuances that I'm able to adjust to make sure that we accomplish the patient's goals for surgery while also having that implant perfectly fit in that location through the use of the patient's own CT scan. We're trying to get the perfect fit where we want it.
Q: How did your first surgery with this patient-specific implant go?
VY: The patient I operated on had several spine surgeries, as well as a spinal cord stimulator, and also had a spinal deformity that I ultimately corrected with this procedure. His outcome has been very good: His leg pain and back pain improved substantially. Particularly in these complex cases, where a patient has several previous surgeries, we really want to make this surgery the last one that the patient needs. Patient-specific implants are one of the strategies that we can use to improve our chances of creating a long-lasting outcome. We all may know of patients who've undergone three, four, five or maybe even six spine surgeries. A lot of this is part of our goal to create a spine surgery that is the last spine surgery a patient ever needs.
Q: Do you see more device companies and surgeons utilizing patient-specific implants?
VY: I think so. Right now, we see Medicrea with Medtronic creating patient-specific rods that allow us to achieve the lordosis we want. A lot of this came out of work that the Scoliosis Research Society has done. We spend hours planning surgery, but oftentimes — particularly in complex spine surgery, multilevel fusions, spinal deformity surgery for scoliosis, revision surgery — we realize in 30 to 40 percent of cases we may not achieve our alignment goals. We measure parameters like pelvic incidence and lumbar lordosis and try to match those. There are lots of software packages that allow us to plan surgery.
But the real question is: How do we execute that surgery as accurately, and with as high a fidelity as possible, in accordance with that plan? We still have a long way to go, because surgeons see outcomes that do not quite match their surgical plan. So, a lot of these patient-specific implants are being designed not only to reduce complications but also to execute and achieve the plan as accurately as possible.
Q: What drawbacks or challenges do smaller practices face when looking to adopt this technology?
VY: I think the turnaround time for the implant being around three to four weeks could be a hindrance. Oftentimes, we need to use the preoperative planning software with high resolution CT scans, which may not be something that most practices are routinely getting. So, there would likely be some adjustments in terms of the workflow, but those would be minor adjustments.