What Is a Combined Anterior and Posterior Cervical Fusion?

A combined anterior and posterior cervical fusion is a spinal surgery that approaches the neck from both the front and the back to decompress nerves, stabilize the vertebrae, and fuse them together. Surgeons sometimes call it a “circumferential” or “360-degree” fusion because hardware and bone graft are placed on both sides of the spine. It is reserved for more complex cervical problems where a single approach would not provide enough stability or decompression on its own, and it carries higher stakes than either approach performed alone.

Why Both Directions at Once

Most cervical spine surgeries use one approach. The anterior route goes through a small incision in the front of the neck, giving access to the discs and vertebral bodies. The posterior route enters from the back of the neck to work on the laminae, facet joints, and spinal canal. Each has strengths: the front approach is excellent for removing herniated discs and collapsed vertebral bodies, while the back approach allows wider decompression across several levels and placement of screws into the lateral masses or pedicles of the vertebrae.

Sometimes, though, neither route alone is enough. The recognized indications for a circumferential approach include patients at high risk for pseudoarthrosis (failed fusion), cervical deformity from degenerative disease or trauma, multilevel spinal metastases, cervical infections, unstable trauma, movement disorders such as cerebral palsy, patients who have already had prior surgeries (especially those with post-laminectomy kyphosis or extensive ossification of a spinal ligament), and situations where rapid, solid fusion is needed.¹ That is a long list, but the common thread is that these patients need both thorough decompression of the spinal cord and a construct rigid enough to hold a compromised spine in alignment while bone heals.

Research comparing anterior-only surgery to combined approaches for unstable cervical injuries has found that, while a combined approach provides a clear biomechanical advantage in stability, clinical outcomes like neurological improvement and complication rates are not always dramatically different between the two.² That finding does not mean combined surgery is unnecessary. It means surgeons reserve it for cases where that extra mechanical stability genuinely matters, rather than using it as a default.

The Role of Cervical Deformity

One of the clearest reasons to operate from both directions is cervical deformity, particularly kyphosis, where the normal lordotic curve of the neck has reversed or flattened. When the spine is badly misaligned, a front-only approach may not restore enough curvature, and a back-only approach may not provide enough anterior column support. One study comparing combined anterior-posterior patients with those treated from a single direction found that combined-approach patients started with worse deformity measurements and that the 360-degree operation offered more advantages for people with a greater degree of malalignment or neurological deficits.³

Patients with cerebral palsy, especially the athetoid type, are a population where this decision comes up regularly. The involuntary neck movements in athetoid cerebral palsy put enormous strain on the cervical spine, and degeneration tends to be severe and multi-level. One study analyzed 63 patients with athetoid cerebral palsy and cervical myelopathy, comparing posterior-only fusion to combined anterior-posterior fusion.⁴ The combined approach is often favored in these patients precisely because their involuntary movements create forces that a single-direction construct may not withstand long-term.

What Happens During the Anterior Part

During the anterior portion, the surgeon makes an incision along a natural skin crease on one side of the front of the neck. The esophagus, trachea, and carotid artery are gently retracted to expose the front of the spine. From here, the surgeon can remove a damaged disc (discectomy) or an entire vertebral body (corpectomy) and replace it with a cage packed with bone graft. A metal plate is typically screwed to the vertebral bodies above and below to hold everything in place.

The cages used in these procedures have evolved considerably. Early designs were metal, but modern cages are often made from a polymer called PEEK, which has the advantage of being radiolucent on imaging (so the surgeon can see how bone is growing through it on follow-up X-rays) and having an elastic modulus closer to bone, which reduces the stress-shielding effect that can weaken surrounding bone. Titanium cages are still used as well, valued for their strength, corrosion resistance, and surfaces that can be modified to encourage bone to grow into them.⁵

What Happens During the Posterior Part

The posterior portion involves an incision down the midline of the back of the neck. The surgeon separates the paraspinal muscles to expose the vertebrae, then performs decompression if needed, typically by removing the lamina (laminectomy) to give the spinal cord more room. Screws are then placed into the lateral masses of the vertebrae, and rods are connected between the screws to lock the spine in the desired alignment.

Lateral mass screw fixation has become the workhorse of posterior cervical instrumentation. Studies confirm it is a safe and effective technique for stabilizing the subaxial cervical spine across a variety of conditions.⁶ One review of 31 patients undergoing posterior cervical decompression and lateral mass screw fixation for cervical spondylotic myelopathy reported good outcomes with fewer complications.⁷ The posterior screws-and-rods construct is doing the heavy mechanical lifting in many combined cases, while the anterior cage and plate handle column support and disc-space restoration.

An interesting finding from cadaveric research is that, in some configurations, adding anterior instrumentation to a five-level posterior lateral mass fixation does not further increase rigidity.⁸ This suggests that the value of the anterior approach in a combined procedure is not always about mechanical stiffness. It often comes down to anterior column reconstruction, direct removal of compressive disc or bone from in front of the spinal cord, and promoting fusion through a wider area of bone contact.

Same-Day Surgery Versus Staged Operations

One of the practical decisions surgeons face is whether to do both the front and back portions on the same day, or to stage them as two separate operations days or weeks apart. Both strategies are used, and the choice depends on the patient’s overall health, the complexity of the problem, and the expected surgical time.

A study comparing same-day combined surgery to staged surgery found that staged patients spent significantly more total time in the operating room (about 8.5 hours versus 7.2 hours for same-day), spent longer under general anesthesia, and had a dramatically higher incidence of postoperative delirium. The adjusted odds of delirium were roughly 23 times higher in the staged group.⁹ That finding makes intuitive sense: two separate rounds of anesthesia and the cumulative stress of two recovery periods are harder on the body, especially for older patients or those with other health issues.

A separate analysis also found differences in staging, reporting that staged patients received substantially more intravenous fluids, had longer hospital stays (roughly 18 days versus 10), and were more likely to need blood transfusions. In that study, smoking and pre-existing cervical myelopathy stood out as the most important risk factors for perioperative complications regardless of staging strategy.¹⁰ So when the patient can tolerate a longer single operation, same-day surgery appears to have some real advantages in avoiding cumulative complications.

The Airway Risk

The complication that makes combined cervical surgery genuinely different from single-approach procedures is airway compromise. The front-of-the-neck approach involves retraction of the esophagus and trachea, and prolonged retraction can cause soft tissue swelling that narrows the airway after the tube is removed. When this is combined with the prone positioning and additional surgical time of a posterior procedure, the swelling risk climbs substantially.

One study that looked specifically at this issue found that 7 out of 10 patients who underwent combined anterior-posterior cervical spine surgery required emergency airway management afterward, compared to roughly 1% of patients who had single-approach cervical surgery. The odds ratio for needing emergency airway intervention after combined surgery was strikingly high.¹¹ That study was small, which is why the confidence interval around that odds ratio was enormous, but the direction of the finding is consistent with what surgeons expect. Most centers now keep patients intubated overnight after combined cervical procedures and closely monitor airway patency before extubation. The risk is real, well-known, and manageable with proper planning, but it is the main reason patients spend time in an intensive care unit after this surgery.

Pseudoarthrosis and Getting the Bone to Fuse

The entire point of a fusion is to get two or more vertebrae to grow together into a single block of bone. When that does not happen, the result is pseudoarthrosis, a false joint where motion persists. Pseudoarthrosis can cause ongoing pain, hardware loosening, and sometimes the need for revision surgery. It is one of the recognized complications of any cervical fusion, and it becomes more of a concern as more levels are fused.¹²

This is actually one of the main arguments for the combined approach in high-risk patients. Placing bone graft both anteriorly and posteriorly doubles the surface area available for fusion. The anterior cage supports the front of the spine structurally while bone grows through it, and the posterior screws and rods immobilize the construct to give that growth the best chance of succeeding. Patients who smoke, have diabetes, take chronic steroids, or are undergoing revision surgery are at elevated pseudoarthrosis risk, and for these patients the belt-and-suspenders approach of a 360-degree construct can tip the odds toward a successful fusion.

Adjacent Segment Disease

One longer-term concern after any cervical fusion, including combined procedures, is the development of problems at the spinal levels next to the fused segment. When several vertebrae are locked into a single block, the levels above and below must compensate by absorbing more movement. Over years, this extra stress can accelerate disc degeneration and cause new symptoms at those neighboring levels.

Research into adjacent segment disease confirms that patient factors like age and pre-existing degeneration, along with surgical factors like the type of fusion, the instrumentation used, and how well alignment was corrected, all influence the risk.¹³ This is worth knowing because combined anterior-posterior fusions often span more levels than single-approach procedures, and the longer the fused segment, the more stress is transferred to the neighboring levels. Good sagittal alignment at the time of surgery may help reduce this risk, which is another reason surgeons pay careful attention to restoring the natural cervical curve during combined procedures.

Hospital Stay and Recovery

A combined anterior-posterior cervical fusion is a big operation, and the recovery reflects that. For context, studies of single-approach cervical surgeries report average hospital stays of about 3 days for anterior procedures and about 5 days for posterior ones.¹⁴ A combined procedure typically means a longer stay, often in the range of 7 to 18 days depending on whether the surgery was done in one session or staged, the number of levels fused, and the patient’s general health.

In the early postoperative period, the biggest concerns are airway management (as described above), wound monitoring for both incisions, and neurological checks to ensure the spinal cord and nerve roots are functioning well. Most patients will wear a cervical collar for weeks to months, though practices vary between surgeons and depend on the stability of the construct. Pain management after combined procedures typically involves a combination of medication strategies, and early mobilization is encouraged as soon as the patient can safely get out of bed.

Longer-term recovery involves physical therapy focused on gradually restoring neck mobility within whatever range is still possible given the fused segments. Many patients notice a significant reduction in arm pain, numbness, or weakness if those symptoms were present before surgery. Recovery of spinal cord function in patients with myelopathy can continue for a year or more. One case report documented a patient with intellectual disability and severe cervical myelopathy who underwent combined anterior and posterior fixation surgery in two sessions and was discharged 45 days after the second operation. A year after surgery, that patient could walk independently.¹⁵

Intraoperative Monitoring

Because the spinal cord is at risk during any cervical spine surgery, and doubly so during a longer combined procedure, surgeons use intraoperative neuromonitoring to watch for trouble in real time. This involves placing electrodes on the patient before surgery begins to continuously monitor signals traveling through the spinal cord and nerves. If the amplitude of those signals drops significantly or the latency changes beyond a threshold, the monitoring team alerts the surgeon, who can then adjust technique, check positioning, or take other steps to prevent a permanent neurological injury.

Neuromonitoring is used in both anterior-only and posterior-only procedures as well, but it becomes especially important in combined cases because of the longer operative time, the need to reposition the patient (typically from supine for the anterior portion to prone for the posterior portion), and the cumulative risk to the spinal cord from two separate decompression maneuvers. Position-related alerts can occur during the transition between positions, which is one reason the anesthesia and surgical teams coordinate closely during this phase of the operation.

How Spinal Fusion Surgery Has Changed Over Time

The idea of fusing the spine is not new. The first spinal fusions were performed in the late nineteenth century using basic instrumentation and techniques that would be unrecognizable today.¹⁶ Over the decades, the field progressed through the development of pedicle screws, modern bone grafts, and interbody cages. The combined anterior-posterior cervical fusion is a product of this accumulated technology and understanding. It became practical only when both anterior plating systems and posterior screw-rod systems were refined enough to be reliably deployed in the same patient during the same operative session. Advances in anesthesia, airway management, and neuromonitoring have all contributed to making a surgery that was once extraordinarily risky into something that, while still major, can be performed with acceptable safety profiles at experienced centers.

Ongoing developments include improvements in cage materials, expandable cages that can be adjusted in situ to fine-tune lordosis, navigation-assisted screw placement that reduces the risk of malpositioned hardware, and biologics designed to accelerate bone fusion. Robotics and augmented reality are in early-stage use at some centers for screw trajectory planning. None of these technologies eliminate the fundamental challenge of the procedure, which is balancing thorough decompression and solid fixation against the cumulative physiological toll on the patient, but they are gradually expanding the population of patients for whom a combined approach is feasible.