By BECKY GILLETTE
John J. Eager, MD, a fellowship-trained spine surgeon with OrthoSouth, has become the first surgeon in the Mid-South to perform the landmark's Carlsmed's aprevo® Phe spinal fusion procedure.
Spinal fusion links two vertebrae together to reinforce a patient’s spinal structure, improve alignment and stability. The procedure uses bone graft and metal instrumentation to achieve osseous fusion with the goal of reducing pain and promoting stability.
The aprevo® platform integrates advanced imaging, AI-driven 3D surgical planning, and precision titanium additive manufacturing to produce custom implants that restore targeted spinal alignment, optimize fit and reduce mechanical complications compared to traditional "off-the-shelf" devices.
"Completing the first aprevo® case in our region was an exciting milestone," said Eager. “By correcting spinal alignment preoperatively and delivering that plan with a patient-specific implant, we reduce the risk of malalignment and recurrent pain – and give patients the best possible chance at long-term relief.”
Eager said these implants reduce operation times and blood loss. When performing the procedure, he has been able to execute a surgical plan to accomplish his preoperative goals utilizing more minimally invasive techniques. This technology allows him to avoid performing larger dissections and multiple spinal osteotomies which are typically needed in adult spinal deformity correction surgery.
Eager said the procedure has proven clinical impact with data from more than over 500 patients across multiple centers showing aprevo® has delivered the targeted alignment with 82 percent of personalized implants achieving alignment within 5 degrees of surgical goals. Enhanced Graft Contact provides 94 percent average implant-to-endplate contact at one year. About 96 percent of personalized implants have zero subsidence at one year. There is also less than a two percent rate of revision for mechanical complications in adult spinal deformity cases.
Eager said there are five steps in the personalized process:
*CT Imaging to create a detailed 3D spine model.
*AI-Based surgical planning for alignment restoration and optimal fit.
*Surgeon review and approval of the personalized implant design.
*3D printing in titanium to exact specifications.
*Hospital delivery for use in the planned fusion procedure.
Eager is often asked how spinal fusion performs compared to disc replacement. which involves the removal of the degenerative disc and implantation of an artificial disc. In both cases, the surgeon is performing a decompression of the spinal cord and/or nerves while seeking to maintain or improve spinal alignment.
Artificial disc replacement can provide critical pain relief while preserving the natural motion of the spine. The procedure has been around for a long time with major improvements in recent years.
“It has evolved significantly over the decades, primarily with advances in materials and engineering,” said Eager. “This allows for better bone integration, improved wear characteristics and expanding indications to multi-level procedures. Implants have improved to provide a more secure attachment to the vertebral bodies with advanced coating surfaces such as porous-coated titanium and hydroxyapatite which encourage osseous integration.
“Articulating components have transitioned from early metal-on-metal or rubber components to more highly durable, highly crossed-linked, ultra-high molecular weight polyethylene and ceramic cores. This newer generation of implants allows for precision sizing and provides a better anatomical fit. Companies have introduced bearing footprints with lower profiles and plates to more closely match the patient’s anatomy and restore disc height.”
With disc replacement surgery, the recovery time for patients to return to activities is generally quicker than with fusion surgery. After disc replacement surgery, patients can expect to spend at least one night in the hospital. However, in select patients, these surgeries may be performed as an outpatient procedure. Patients resume normal activities of daily living immediately after surgery. However, rigorous activity is usually restricted for up to six weeks.
Candidates for either spinal fusion or disc replacement are first treated with a conservative approach utilizing non-surgical care. Only after these methods have failed to relieve a patient’s symptoms do they consider proceeding with surgery.
“It is possible to treat disc pathology conservatively with physical therapy, targeted injections and observation,” Eager said. “Good candidates for disc replacement are patients with degenerative or herniated discs who have preserved spinal motion and minimal arthritis. Disc replacement is designed to preserve the motion of the spine. The outcomes are just as good as with fusion surgery but with the added benefit of motion preservation. If a patient has minimal spinal motion or diffuse arthritis, they may be better served with a fusion surgery. Additionally, if patients exhibit any evidence of spinal instability, they would be indicated for spinal fusion as opposed to disc replacement.”
Some common misconceptions about disc replacement surgery are that it is new and experimental, which is far from the case. This surgery has been proven to have long lasting, significant therapeutic results.
“There are inherent risks with any surgery,” he said. “Risks with artificial disc replacement include issues such as subsidence and the implant components wearing out over time. An artificial disc replacement is designed to last a patient’s lifetime. Clinical data has shown implant survival rates surpassing multiple decades. Some patients have kept their original implants 20 to 30 years. Wear-and-tear biomechanical testing suggests the implants can last 40-plus years.”
Eager personally has not seen an implant fail requiring another surgery, but catastrophic failure could require revision surgery necessitating the removal of implants and transition to fusion surgery.
“It goes back to the implant design which can withstand everyday mechanical stressors,” Eager said. “In addition to disc replacement preserving motion and reducing pain, it reduces the stress at adjacent levels. This important aspect of disc replacement surgery seeks to mitigate the risk of wear and tear above and below the surgery site to reduce the chances of adjacent segment disease.”
It is also a faulty notion that this procedure is primarily for younger people. Eager said age can play a role in determining candidacy if the bone quality is adversely affected, and if there are multi-level arthritic joints and loss of motion.
Disc replacement is most commonly performed in the cervical spine, which requires a smaller implant, and in the lumbar spine, which requires larger implants for a better anatomical fit.
Eager specializes in the diagnosis and treatment of neck and back pain, as well as musculoskeletal oncology. In addition to spinal fusion and disc replacement, his areas of expertise include degenerative spine conditions, minimally invasive spine surgery, spinal deformity, spine trauma, spinal tumors and revision spine surgery. He is dual-fellowship trained in complex spine surgery and musculoskeletal oncology.
Prior to going to medical school, Eager had a career in aviation as a licensed commercial pilot and flight instructor. He still flies when time permits, but keeps very busy with his medical practice and family.