For decades, spinal fusion was a familiar answer for degenerative disease requiring stabilization. That starting point is beginning to shift.
Recent Becker’s reporting shows cervical disc replacement gaining ground, as long-term evidence matures, surgeons experimenting with hybrid constructs that combine fusion and arthroplasty, and patients arriving with stronger preferences around preserving motion. At the same time, insurers are applying increasingly granular authorization requirements to fusion and its alternatives.
The result is not a wholesale move away from fusion. Surgeons continue to describe it as necessary for instability, deformity and other pathology where motion preservation is inappropriate. Instead, the debate is shifting toward when fusion should remain the default, which levels truly require stabilization and how surgeons prove that choice to patients and payers.
Fusion is losing its default status
Lauren Matteini, MD, a spine surgeon at Geneva, Ill.-based Fox Valley Orthopedics, told Becker’s that cervical disc replacement has become the starting point for many patients in her practice. She evaluates the anatomy for reasons that arthroplasty would be inappropriate rather than beginning with fusion and determining whether the patient qualifies for an alternative.
“I’m an arthroplasty until you prove to me otherwise that you need a fusion,” Dr. Matteini said.
Her approach is not arthroplasty at all costs. Dr. Matteini said spondylolisthesis, substantial posterior compression and other anatomical findings can make fusion more appropriate. But she believes increased confidence in cervical disc replacement has shifted the burden of proof: The question increasingly becomes why motion should be eliminated rather than whether it can be preserved.
Ramin Raiszadeh, MD, of San Diego Spine and Brain Institute, has described a similar evolution. He told Becker’s that disc replacement has become his default for many young, active and healthy patients, while fusion remains necessary for patients with instability, fractures, infection, malignancy, osteoporosis and other conditions where a motion-preserving implant could fail.
That distinction is important. Tan Chen, MD, an orthopedic spine surgeon and assistant professor at the University of Virginia School of Medicine in Charlottesville, told Becker’s that motion preservation should expand surgeons’ options rather than simply replace fusion.
“The goal isn’t to avoid fusion, it’s to avoid unnecessary fusion,” Dr. Chen said.
Patients are changing the conversation
The pressure to reconsider fusion is not coming only from surgeons. Dr. Matteini told Becker’s that patients increasingly arrive having researched arthroplasty and sometimes seek second opinions after another surgeon recommends fusion. They are asking whether they qualify for disc replacement and why motion preservation was not initially offered.
Todd Lanman, MD, a spinal neurosurgeon at Beverly Hills, Calif.-based Lanman Spinal Neurosurgery, has seen patient expectations evolve over more than three decades in practice. Earlier in his career, he said, patients were primarily focused on getting out of pain. Today, they are more likely to ask how an operation will affect their activity, alignment and range of motion years later. Some arrive already familiar with specific artificial discs.
Dr. Chen has seen the same enthusiasm, but he cautioned that patient interest can run ahead of the evidence. He said motion-preservation technologies should not become universal fusion-avoidance tools, and longer-term evidence is still needed to establish when maintaining motion consistently translates into better outcomes.
That leaves surgeons balancing two changes at once: patients increasingly expect alternatives to be considered, but patient preference alone cannot determine whether preserving motion is clinically appropriate.
Long-term evidence is complicating both sides
More than two decades of cervical disc replacement experience have answered some early questions while making others less straightforward. Daniel Riew, MD, chief of cervical spine surgery and co-director of the spine fellowship at New York City-based Columbia University, began implanting artificial cervical discs in 2002. He told Becker’s that long-term evidence has demonstrated durability and outcomes comparable to fusion in appropriately selected patients. “It has withstood the test of time,” Dr. Riew said.
One early expectation, however, has proved less clear. Motion preservation was expected to dramatically reduce adjacent-level disease by eliminating the additional mechanical demands thought to result from fusion. Dr. Riew said longer-term evidence has shown a statistically significant reduction in adjacent-level reoperation with disc replacement in some analyses, but the difference was smaller than early proponents expected. He pointed to natural aging across all spinal segments as another major driver of degeneration.
That makes the fusion debate more nuanced. The argument for arthroplasty is no longer simply that preserving motion will prevent neighboring segments from deteriorating. The potential benefits also include maintaining movement and, for some patients, faster recovery, while fusion retains clear advantages when stability is the primary problem.
Multilevel disease is breaking down the binary choice
The next evolution may also challenge the idea that a patient with multiple diseased levels must receive the same treatment at every segment.
Dr. Raiszadeh told Becker’s that he routinely performs hybrid constructs, combining fusion at an unstable level with disc replacement at an adjacent level where he believes motion can safely be maintained. In the past, a patient with multilevel disease might have received fusion across all affected segments.
The approach allows surgeons to evaluate pathology level by level: stabilize the segment that requires stability while preserving movement elsewhere.
Hybrid constructs can involve off-label use of disc replacement devices, and Dr. Raiszadeh emphasized that patients need to understand which aspects of the procedure fall inside or outside FDA-cleared indications. Despite that issue, he said insurance approval has not been a major barrier in his own practice. “I routinely do hybrid constructs, I get authorized all the time,” he said.
Dr. Matteini has also identified hybrid constructs as an area where she expects greater use, particularly when one diseased segment requires fusion but an adjacent level remains suitable for arthroplasty. She told Becker’s that the goal should be greater flexibility to tailor treatment to each level rather than forcing an entire cervical spine into one category.
Payers are becoming part of the fusion decision
Even as surgical decision-making becomes more individualized, insurance authorization is moving in the opposite direction.
Five spine surgeons told Becker’s in August that fusion authorization requirements increasingly involve detailed documentation of conservative treatment, individual operative levels, CPT codes, implant systems and payer-specific criteria.
Bryce Basques, MD, spine surgeon and director of minimally invasive and endoscopic spine surgery at Brown University in Providence, R.I., said algorithmic prior authorization can require physicians to structure clinical documentation around specific insurer terminology.
“Writing notes no longer means documenting medical decision-making,” Dr. Basques said.
Issada Thongtrangan, MD, an endoscopic and minimally invasive spine surgeon at MicroSpine in Scottsdale, Ariz., similarly told Becker’s that authorization increasingly depends on documenting the sequence and duration of physical therapy, medications, injections, patient-reported outcomes and imaging in the precise format insurers require. Missing language can trigger a denial even when the surgeon believes the procedure is indicated.
Coverage friction also affects alternatives to fusion. Dr. Matteini said obtaining authorization for arthroplasty adjacent to a previous fusion or in other less conventional situations can remain difficult even when she believes motion preservation is the better clinical choice. She has also pointed to a reimbursement structure that generally pays more for fusion than cervical arthroplasty.
The tension is becoming harder to ignore: Surgeons are moving toward increasingly individualized decisions about which segments require stabilization while payer systems rely on increasingly standardized criteria to determine which procedures will be covered.
The definition of success is getting longer
The final debate may be less about what happens in the operating room than what happens years afterward. Dr. Lanman has argued that spine surgeons should increasingly judge an operation by what it allows patients to do a decade later. His planning considers neighboring levels, alignment, age, activity goals and the possibility that an operation solving today’s problem could influence the next one.
That approach has its own limits. Treat too little, and a patient may return years later with another diseased level. Treat too aggressively, and the surgeon risks operating on pathology that may never have become symptomatic. Dr. Lanman acknowledged that surgeons can reasonably disagree over how far ahead to plan.
He nevertheless expects the presumption surrounding fusion to weaken as artificial disc replacement accumulates longer-term evidence.
“In 10 years from now, insurance companies won’t ask, ‘Why do you want an authorization for a fusion?’” he said.
His prediction is not the current standard. Dr. Lanman himself has emphasized that instability, poor bone quality, severe facet degeneration, deformity and extensive bony disease can make fusion the more appropriate operation.
That may ultimately define the next phase of the debate. The fight over spinal fusion is not whether the operation still belongs in spine surgery. It is how much of the spine truly needs to be fused, and how convincingly surgeons will have to demonstrate that the answer is fusion rather than one of the alternatives increasingly available to them.
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