Anterior Cervical Discectomy and Fusion | Does this surgery cause more cervical spine instability and deformity?
Many people come to Caring Medical because they have issues with cervical neck instability and radicular pain. It is for these reasons they have a recommendation for Anterior Cervical Discectomy and Fusion. In separate articles I discuss Cervical neck instability, and, Atlantoaxial instability, and why these conditions can send you to Anterior Cervical Discectomy and Fusion. This article will focus more on the surgical outcome of the surgery.
Anterior cervical discectomy and fusion (ACDF or sometimes anterior cervical decompression) is a cervical neck surgery that is recommended to patients that have been diagnosed with a pinched nerve in the neck that is causing pain, weakness, numbness and other symptoms of cervical radiculopathy.
- The discectomy removes a damaged disc identified as causing the patient’s problems. Once the disc is removed the fusion part of the surgery is performed.
- The fusion surgery’s goal is to successfully place a bone graft and/or an implant where the original disc was removed. The ultimate goal of the surgery is cervical stability and pain-free movement.
- The surgery can also address removing bony overgrowth or bone spurs that can pinch on the cervical neck nerves and be causing the problems of cervical radiculopathy. Typically numbness or weakness in the shoulders, arms, legs and upper neck region.
At what point is fusion surgery considered “high risk”?
As I have discussed in numerous pages on this website, not only has it been shown that cervical fusion can be an inappropriate treatment for many patients, worse off, is that the fusion can do much more harm than good. One area of harm is adjacent segment disease. This is a failed surgery condition in which the adjacent vertebrae to the fused section rapidly degenerates because of newly created surface stresses by the immobility of the fused segment.
Make no mistake, there are times where a person does need a cervical fusion. If this person suffered a severe fracture in the neck then a cervical fusion would be called for. But many times, people get cervical fusion because they have complaints that can be many times treated without the need for cervical fusion. These complaints include:
In our office, on detailed physical examination, we find that many of the people who seek a consultation for the problems listed above have problems caused by ligament weakness, which causes the vertebrae to press on the nerves. This can be treated non-surgically.
But if the examination does not look for ligament problems, if the examination is focused on reading the MRI, the cervical ligaments will be overlooked. Cervical fusion will be recommended. To the patient getting a surgical consultation, surgery sounds like the only answer. It is not as we will see below.
Let’s discuss the surgery.
Anterior Cervical Discectomy and Fusion Recovery
There are many lifestyle changes following Anterior cervical discectomy and fusion.
For some, these lifestyle changes will be short-term, for others long-term, for others still indefinitely or non-ending in cases of complication and the need for revision neck surgery.
- You may have to deal with problems of constipation and stressful bowel movements that may put a strain on your neck.
- You will likely need narcotic pain medications but will not be allowed to take NSAIDs such as Aspirin, Advil, Motrin, Aleve, Celebrex, etc., for fear that these medications will negatively impact the bone healing needed to complete the fusion. This recommendation can be anywhere from 3 to 6 months.
- Long-term alteration in your movements will part of your recovery. This will include limited head movements, being able to lift common everyday objects over 5 pounds (like a gallon of milk or water), and regulating the amount of time you can sit.
- You may not be able to drive a car, have sex, or exercise for some time. (Please see my article Patients report problems with sexual function after cervical spine surgery)
Understanding Anterior Cervical Discectomy and Fusion surgery, risks, complications and inappropriateness.
As mentioned above, when your cervical vertebrae are fused to limit cervical instability and related symptoms, the force and energy in your neck movements are transferred to the vertebrae below the fusion and above the fusion. This is why people suffer from the same symptom at different locations a year to 3 years later. This is why many people are sent back to surgery to fuse more segments and why many get the symptoms back and they can even be worse. Let’s explore research from some of the leading universities and research hospitals that support these findings.
Within 10 years, 1 in 4 patients is at risk of clinical adjacent segment disease.
Doctors at the University of Alberta noted in the Canadian Journal of Neurological Sciences: “Cervical spine clinical adjacent segment pathology has a reported 3% annual incidence and 26% ten-year prevalence. Its pathophysiology remains controversial, whether due to mechanical stress of a fusion segment on adjacent levels or due to patient propensity to develop progressive degenerative change.”(1)
Simply, within 10 years, 1 in 4 patients are at risk of clinical adjacent segment disease because of unnatural stress and destructive forces being placed on the cervical spine.
Failure in stand-alone Anterior Cervical Discectomy and Fusion Implants
Doctors at the Swedish Neuroscience Institute, Swedish Medical Center, in Seattle Washington led a study examining the failure patterns in standalone Anterior Cervical Discectomy and Fusion Implants. The study appeared in the September 2017 edition of the journal World neurosurgery.(2)
Take home points:
- The goal of the study was to see how to help patients who suffered from Anterior cervical discectomy and fusion failure.
- Two-hundred eleven (211) patients were included in the study.
- There were 11 (5.2%) readmissions.
- There were 10 (4.74%) implant failures (five involving single-level surgery and five involving two-level surgery),
- There were seven cases of pseudoarthrosis (non-union fusion failure)
- Mechanisms of failure included:
- a C5 body fracture (the fusion cracked the vertabrae.
- Fusion in a kyphotic alignment following graft subsidence, (The bone/fusion collapsed causing a “hunchback,” curve in the patient).
- and acute spondylolisthesis, the condition of “slipped disc” or “slipped vertebra.
The surgery to fix the surgery. Revision and more fusion is no easy fix
- Revision surgery following standalone anterior cervical implants can be complex.
- Surgery from behind Posterior (behind). Posterior cervical fusion remains a valuable approach to avoid possible vertebral body fracture and loss of fusion area associated with the removal of implants secured through the endplates of adjacent vertebral bodies.
Doctors at South Korea’s Pusan National University published this research in the Journal of Korean Neurosurgical Society.
The quick points:
- Thoracic spine involvement: Prior to Anterior cervical discectomy and fusion doctors should examine the T1 slope (for correct or incorrect position) and C2-C7 sagittal vertical axis (this is a measure to determine is the spine is “plumb” in a straight line and in correct balance).
- If these two factors are out of alignment there is a higher risk kyphosis after laminoplasty (The bone/fusion collapsed causing a “hunchback,” curve in the patient), which is accompanied by posterior neck muscle damage.
- The researchers warn that these important preoperative parameters have been under-estimated in anterior cervical discectomy and fusion.
Patients with cervical instability are getting surgeries that cause more instability and deformity
COMMENT: What these researchers are warning is that the cervical spine and its attachment to the thoracic spine are more unstable than thought. This presents a paradox, patients with cervical instability are getting surgeries that cause more instability and deformity. Here is the result of this research:
- Forty-one (41) patients who underwent ACDF with a stand-alone polyether-ether-ketone (PEEK) cage at one-year follow-up. Fifty-five segments (27 single-segment and 14 two-segment fusions) were included.
- The subsidence (collapse) and pseudarthrosis (non-union) rates based on the number of segments were:
- 36.4% collapse
- 29.1% non-union
- CONCLUSION: Surgeons should examine and be aware of the risk factors associated with T1 slope (for correct or incorrect position).(3)
Cervical fusion – there is an option
The final outcome of a successful cervical fusion is that the vertebrae can no longer move. This will prevent the nerve from getting pinched, BUT, the neck still moves. The neck’s motion is now transferred to the vertebrae below the fusion and above the fusion. In essence, the problem the surgery sought to fix only transferred excessive pressures to the vertebrae below it and above it. This is why people with cervical fusions inevitably, a year to three years later get the symptoms back
Now, by definition, that means if somebody is recommended a cervical fusion it means that the doctor is saying that it’s instability causing the problem. In my opinion, the best treatment for cervical instability is Prolotherapy of the neck, not cervical fusion. If it is the excessive movement of the vertebrae that is pinching on the nerves cause terrible pain, migraine headaches, vertigo, all types of symptoms, then Prolotherapy can strengthen the cervical ligament, address the symptoms and not rob the patients of their natural neck movements.
Caring Medical research on alternatives to Discectomy and Fusion
- The cervical capsular ligaments are the main stabilizing structures of the facet joints in the cervical spine and have been implicated as a major source of chronic neck pain. Such pain often reflects a state of instability in the cervical spine and is a symptom common to a number of conditions such as disc herniation, cervical spondylosis, whiplash injury and whiplash associated disorder, post-concussion syndrome, vertebrobasilar insufficiency, and Barré-Liéou syndrome.
When the capsular ligaments are injured, they become elongated and exhibit laxity, which causes excessive movement of the cervical vertebrae.
- In the upper cervical spine (C0-C2), this can cause symptoms such as nerve irritation and vertebrobasilar insufficiency with associated vertigo, tinnitus, dizziness, facial pain, arm pain, and migraine headaches.
- In the lower cervical spine (C3-C7), this can cause muscle spasms, crepitation, and/or paresthesia in addition to chronic neck pain.
- In either case, the presence of excessive motion between two adjacent cervical vertebrae and these associated symptoms is described as cervical instability.
Therefore, we propose that in many cases of chronic neck pain, the cause may be underlying joint instability due to capsular ligament laxity. Furthermore, we contend that the use of comprehensive Prolotherapy appears to be an effective treatment for chronic neck pain and cervical instability, especially when due to ligament laxity. The technique is safe and relatively non-invasive as well as efficacious in relieving chronic neck pain and its associated symptoms.
My own cervical radiculopathy and Prolotherapy treatment – Ross Hauser MD
Dr. Hauser explains his own problems with cervical instability and his treatments with Prolotherapy. With the use of digital motion X-ray, Dr. Hauser explains his non-surgical recovery.
If you have a question about options to Anterior Cervical Discectomy and Fusion, you can get help and information from our Caring Medical Staff.
1 Jack A, Hardy St-Pierre G1, Nataraj A. Adjacent Segment Pathology: Progressive Disease Course or a Product of Iatrogenic Fusion? Can J Neurol Sci. 2017 Jan;44(1):78-82. doi: 10.1017/cjn.2016.404. [Google Scholar]
2 Alonso F, Rustagi T, Schmidt C, Norvell DC, Tubbs RS, Oskouian RJ, Chapman JR, Fisahn C. Failure Patterns in Standalone Anterior Cervical Discectomy and Fusion Implants. World Neurosurgery. 2017 Sep 20. [Google Scholar]
3 Lee SH, Lee JS, Sung SK, Son DW, Lee SW, Song GS. A Lower T1 Slope as a Predictor of Subsidence in Anterior Cervical Discectomy and Fusion with Stand-Alone Cages. Journal of Korean Neurosurgical Society. 2017 Sep;60(5):567. [Google Scholar]