4- And 5-Level Anterior Fusions Of The Cervical Spine

If neck pain becomes more severe, interferes with daily tasks, or is associated with swelling and redness, it is crucial to consult a healthcare professional. At Complete Orthopedics, our expert team specializes in addressing neck issues through customized treatment plans and surgical solutions. We prioritize understanding your symptoms, diagnosing the underlying causes, and suggesting the most suitable treatments or surgeries.

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Overview

Performing arthrodesis on four or five levels in the cervical spine is an infrequent surgical procedure, even in high-volume spine centers. Currently, multilevel discectomies and corpectomies are typically only necessary for the treatment of degenerative conditions, post-traumatic or post-surgical deformities, and instability related to neoplasms.

In such cases, the prevalence of diffuse spinal canal constriction and kyphosis is high, and the viable surgical alternatives are mainly anterior. Re-establishing cervical lordosis may be advantageous in terms of neurological recovery and clinical outcomes.

The biomechanical basis for successful multilevel anterior cervical procedures should be highlighted in light of the results and challenges associated with 4- and 5-level cervical fusions. Literature has raised concerns about the limitations of graft, cage, and plate failures, especially in multilevel corpectomies, despite the use of plates with rigid screw-plate locking mechanisms.

Confirmed complications associated with multilevel strut grafting and end-construct plate fixation without posterior fixation include dislodgement or loosening of the graft, cage, or plate at screw-plate or screw-bone interfaces, postsurgical kyphosis, and pseudoarthrosis.

As the number of decompressed levels increased, there was an increase in the rate of failures. Some of the possible outcomes include injury to the vascular system, esophagus, or nerves. A direct relationship has been observed between the mechanical stability of the fusion construct and the fusion rates in the spine.

The hybrid technique is a solution to this concern in multilevel procedures. A successful alternative to multilevel corpectomies for patients requiring decompression and fusion at three or more levels is to perform discontinuous corpectomies combined with adjacent-level discectomy while retaining the intervening body.

This approach has been effective in avoiding plate loosening or graft migration. The hybrid technique enhances the natural mechanical stability of the construct, aids in correcting kyphotic deformity, preserves the reconstructed alignment, and reduces the risk of deterioration at the screw-bone interface. The use of hybrid or continuous ACDF techniques increases the number of graft/bone interfaces that need to undergo osseous union compared to long interbody grafts and cages.

The stability of the spine that is achieved with an anterior cervical screw-plate system depends on several factors such as the plate design, the quality of bone-screw and plate-screw interfaces, the diameter and depth of the major screw, and the density of the bone. A larger and longer screw placement can enhance the initial stability of cervical osteosynthesis, as observed in our patients.

Screw toggling refers to a phenomenon where forces from non-fixed cantilever beam screws cause damage to both the bone and the screw-bone interface. The screw can move and come into contact with the interface between the bone graft and plate, which can reduce the contact surface and potentially decrease the likelihood of achieving a solid fusion.

Currently, clinical failures of constrained anterior cervical plates (with or without dynamic features) are typically not due to implant breakage or bending, but rather at the interface between the bone and instrumentation.

Loosening of screws in the CS-plate may occur due to the implant’s rigid long fixed-moment arm cantilever beam, which may not provide sufficient resistance to translational forces, resulting in the deterioration of the screw-bone interface and eventual failure.

The longer the implant, the more susceptible it is to these effects. To enhance resistance against axial and translational loads, additional points of fixation can be incorporated, as is the case with the hybrid technique or by using posterior fixation.

In terms of maintaining reconstructed lordosis and construct rigidity, CS plate systems are generally more effective than NC-ones. When 360 stabilization techniques are utilized in testing or measuring, there is a high level of certainty, especially in cases where long corpectomies are performed.

In such cases, it has been demonstrated that posterior stabilization on its own is more effective than anteriorly plated reconstructions. The combination of the hybrid technique and multilevel ACDF can provide ample decompression even in cases of significant cervical stenosis. This approach also reduces the number of corpectomy levels needed, consequently decreasing the requirement for posterior support.

Influence Of Cervical Lordosis

The sagittal plane neutral geometry of the cervical spine is crucial to maintaining an upright posture with minimal muscular effort. However, cervical kyphosis (CK) can cause overload of the anterior parts of the spine and result in painful attenuation of the posterior ligaments and facet capsules, muscle fatigue, and imbalance.

Failed surgical restoration of lordosis is one of the main causes of CK. Although a ‘normal’ or ‘pathological’ cervical curvature has not been defined, it is essential to restore a lordotic curvature to balance the sagittal profile and prevent further kyphosis.

Hybrid and ACDF techniques are useful in the reconstruction of cervical lordosis. The segmental distraction and lordotic restoration obtained using wedged interbody grafts/cages with ACPS are useful in foraminal and central decompression as the cord slightly shifts posteriorly, away from mainly anteriorly situated stenosis. Mean correction in patients with 2- and 3-level corpectomies was 6.8 in the series.

Adjacent Disc Degeneration

The impingement of adjacent-level ACPs during primary and secondary migration can lead to adjacent-level pathology and implant loosening, causing changes in construct geometry.

Although symptomatic secondary plate impingement is observed only once in a series of patients, its incidence should be prevented by enhanced constructed rigidity. Symptomatic adjacent-level pathology after ACDF is reviewed as high as 15%. The progression of ADD also seems to reflect the normal course of adjacent levels not included in the fusion construct at the index procedure.

If there is sufficient TCL and lordosis at the fusion block with an anteriorly located stenosis accompanying ADD, the authors currently recommend implant removal and ACDF at the involved segment. In case of ADD, particularly at the CTJ, 360 stabilization should be considered to prevent construct failure due to the long lever-arm resulting from the preexisting cephalad fusion block.

Clinical Failures In Multilevel Anterior Cervical Constructs

The clinical outcomes of multilevel cervical anterior fusion vary and there is a lack of details on the number of instrumented vertebrae, decompressed levels, and the usage of the Halo. Anecdotal reports of construct failures in multilevel corpectomies with stand-alone strut grafts have been reviewed as high as 10-50%. Studies suggest that anterior devices in multilevel fusions and corpectomy cases should be supported by posterior stabilization, particularly pedicle screw fixation.

However, added posterior stabilization comes with added risks, particularly in elderly and frail patients, such as a higher rate of infection, surgical morbidity, increased hospital stay, myofascial pain, and axial neck pain. Added stabilization with circumferential instrumentation of plated multilevel discectomies and corpectomies can improve outcomes.

Clinical Outcome And Surgical Complications

Surgical complications for 4- and 5-level anterior fusions are comparable and even lower than what is reported in the literature. Temporary dysphagia is observed in 17.6% and transient hoarseness in 11.8% of patients.

The incidence of RLN symptoms is the highest with 9.5% in anterior redo surgeries. No serious complications such as dural, neural, esophageal, or vertebral artery injury are observed. The majority of patients show good or excellent outcomes following an average follow-up of 27.4 months. Loss of cervical motion is not a significant concern, and the evidence of PACS has no adverse effect on clinical outcomes.

The majority of patients show a lordotic cervical posture at follow-up, and reconstruction of cervical lordosis is favorable. However, further investigation is needed to determine the amount of lordosis that needs to be reconstructed and the cut-offs below which clinical outcomes decrease.

If a comprehensive approach including complete decompression, distraction, grafting, reconstruction of a cervical posture with lordosis, and the use of anterior cervical plating system is implemented, it is possible to attain favorable clinical outcomes in multilevel ACDF procedures.

Constrained plates within ACPS provide greater stability to the structure compared to non-constrained plates. It is advisable to plan for early stabilization and fusion with 360-degree coverage, such as after corpectomies involving more than two levels.

Based on the risks associated with using current anterior non-locking and locking plate systems to stabilize multilevel corpectomies in the cervical spine, it is necessary to develop stronger anterior fixation devices that can eliminate the need for posterior supplemental fusion in highly unstable multilevel decompressions.

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Advances in Spine Surgery and Future Directions

Ongoing research and technological advancements are continually improving the outcomes of cervical spine surgeries. Key areas of development include:

  • Biologics: The use of growth factors and stem cell therapies is being explored to enhance bone healing and increase the success rates of spinal fusions.
  • Minimally Invasive Techniques: These approaches aim to reduce recovery times and minimize complications by using smaller incisions and advanced imaging technologies to guide the surgery.
  • Enhanced Implants and Materials: Innovations in implant design and materials are improving the stability and longevity of spinal fusions.

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Conclusion

4- and 5-level anterior cervical spine fusions are complex but highly effective surgical interventions for patients with severe cervical spine degeneration. By understanding the procedure, recovery process, and potential risks, patients can make informed decisions about their treatment options. With advances in surgical techniques and materials, the future looks promising for those requiring extensive cervical spine surgery.

Do you have more questions?

How long does the surgery typically take?

A 4- or 5-level anterior cervical spine fusion usually takes approximately 4 to 6 hours. The exact duration depends on the complexity of the patient’s condition and the surgical approach.

Will I need to wear a neck brace after surgery?

Yes, most patients are required to wear a neck brace or cervical collar for several weeks to support the neck and ensure proper healing.

How long will I need to stay in the hospital after the surgery?

The typical hospital stay is 2 to 3 days, although it can vary based on the patient’s recovery progress and overall health.

What are the signs of a successful fusion?

Successful fusion is indicated by the alleviation of preoperative symptoms, stable vertebrae on imaging studies, and the absence of pain at the fusion site

What are the potential long-term restrictions after surgery?

Patients are generally advised to avoid heavy lifting, high-impact activities, and certain neck movements to prevent strain on the fused segments.

How is pain managed post-surgery?

Pain management includes medications such as opioids, non-steroidal anti-inflammatory drugs (NSAIDs), and muscle relaxants, as well as physical therapy.

Can this surgery affect my ability to drive?

Yes, driving is usually restricted for several weeks post-surgery, until the patient regains sufficient neck mobility and is off pain medications that can impair driving ability.

What follow-up care is required?

Follow-up care includes regular visits to the surgeon for X-rays to monitor fusion progress, physical therapy sessions, and adherence to post-operative care instructions.

What are the alternatives to multi-level ACDF?

Alternatives may include less invasive surgical procedures, cervical disc replacement, or continued conservative treatments like physical therapy and injections.

Are there lifestyle changes I need to make post-surgery?

Yes, maintaining a healthy weight, practicing good posture, avoiding smoking, and following a regular exercise program are crucial for spinal health.

What is the success rate of 4- and 5-level ACDF?

Success rates are generally high, with most patients experiencing significant pain relief and functional improvement, though exact rates can vary.

How does smoking affect the healing process?

Smoking can significantly hinder bone healing and increase the risk of non-union, as well as other complications such as infection.

Can the surgery be performed on elderly patients?

Yes, but the risks may be higher in elderly patients due to comorbidities and reduced bone healing capacity. Each case is evaluated individually.

What imaging studies are used to diagnose the need for this surgery?

Diagnostic imaging includes X-rays, MRI, and CT scans to assess the condition of the cervical spine and the extent of degeneration or nerve compression.

Is it possible to have this surgery more than once?

While possible, it is typically more complex and carries increased risks. Revision surgery may be needed in cases of non-union or adjacent segment disease.

How does the surgeon decide between using autografts, allografts, or synthetic materials for fusion?

The choice depends on factors such as patient health, the extent of fusion needed, and the surgeon’s preference. Autografts have high success rates but require an additional surgical site.

What is adjacent segment disease?

Adjacent segment disease is the degeneration of the vertebrae and discs adjacent to the fused segments, caused by increased stress and motion in those areas.

Can physical therapy start immediately after surgery?

Physical therapy usually begins a few weeks post-surgery, starting with gentle exercises and gradually progressing to more intensive activities as healing progresses.

Are there any dietary restrictions after the surgery?

Generally, there are no specific dietary restrictions, but a balanced diet rich in calcium and vitamin D can support bone healing.

How soon can I return to work after surgery?

Return to work depends on the nature of the job and the individual’s recovery. Sedentary work may be resumed in 4-6 weeks, while physically demanding jobs may require several months.

What are the signs of complications after surgery?

Signs of complications include increased pain, redness, swelling, fever, difficulty swallowing, or new neurological symptoms. Immediate medical attention is required if these occur.

Can I engage in sports or physical activities after recovery?

Many patients can return to low-impact sports and activities after full recovery. High-impact sports should be approached with caution and under medical advice.

What are the benefits of minimally invasive surgery compared to traditional ACDF?

Minimally invasive techniques may offer shorter recovery times, less post-operative pain, and reduced risk of complications, but may not be suitable for all cases.

What type of anesthesia is used during the procedure?

General anesthesia is administered for a 4- or 5-level ACDF. This ensures that the patient is completely unconscious and free from pain throughout the surgery. The anesthesiologist will monitor vital signs continuously to ensure the patient’s safety.

Dr Vedant Vaksha

I am Vedant Vaksha, Fellowship trained Spine, Sports and Arthroscopic Surgeon at Complete Orthopedics. I take care of patients with ailments of the neck, back, shoulder, knee, elbow and ankle. I personally approve this content and have written most of it myself.

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