Anterior Cervical Discectomy and Fusion – The evidence
Ross Hauser, MD | Caring Medical Regenerative Medicine Clinics, Fort Myers, Florida
Danielle R. Steilen-Matias, MMS, PA-C | Caring Medical Regenerative Medicine Clinics, Oak Park, Illinois
Katherine L. Worsnick, MPAS, PA-C | Caring Medical Regenerative Medicine Clinics, Fort Myers, Florida
David Woznica, MD | Caring Medical Regenerative Medicine Clinics, Oak Park, Illinois
Anterior Cervical Discectomy and Fusion – The evidence that this surgery can 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 we 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. If you are reading this article it is likely that you have been recommended to this surgery and you are looking for other ways.
It starts with a pinched nerve in the neck
- People do benefit from Anterior Cervical Discectomy and Fusion. People who have neck injuries from sport or accident where bones are fractured are likely to need fusion surgery. This article will focus on “elective,”meaning you choose to have a surgery that is not addressing an urgent health crisis.
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 we 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 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 surgical options. Here we will bring in the opinions of cervical neck surgery specialists.
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.
- A March 2019 study (1) from the Ohio State University Wexner Medical Center If you suffer from metabolic syndrome, (obesity, high blood pressure, high cholesterol, diabetes), you will likely have to stay in the hospital a few days longer than usual.
- 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.”(2)
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.
Anterior cervical spondylosis surgery: a retrospective study with long-term follow-up found that fusion significantly and negatively alters the curve in the neck
In February 2018, orthopedic surgeons at Jinzhou Medical University in China wrote in the Journal of Orthopaedic Surgery and Research (3) about their investigation of the incidence and causes of non-fusion segment disease, both adjacent and non-adjacent to a fused segment, after anterior cervical fusion.
Here are the results of their investigation:
- 171 patients who had an anterior cervical decompression and fusion were followed clinically for more than 5 years.
- Of the 171 patients reviewed, 16 patients had non-fusion segment disease (9.36%), of which 12 had adjacent segment disease and 4 had non-adjacent segment disease.
- Postoperative cervical lordosis in the non-fusion segment disease group was significantly smaller than that of the disease-free group
- The incidences of disc degeneration in unfused segments were more severe in the non-fusion segment disease group than in the disease-free group
- The major factor affecting non-fusion segment disease is postoperative cervical lordosis followed by cervical disc degeneration.
The conclusion: “The incidence of symptomatic non-fusion segment disease after anterior cervical arthrodesis has multifactorial causes. Postoperative cervical lordosis and disc degeneration in non-fusion segments were major factors in the incidence of non-fusion segment disease.”
The second cervical spine fusion makes the cervical lordosis even worse
Surgery failed to restore or maintain the cervical lordosis
In May 2018, spinal surgeons operating in German and Egypt wrote in the medical journal Spine (4) about the problems of the second cervical neck surgery to fix the problems of cervical adjacent segment disease
Let’s focus on the fact pointed out by the researchers:
- “Anterior Cervical Discectomy and Fusion has provided a high rate of clinical success for the cervical degenerative disc disease; nevertheless, adjacent segment degeneration has been reported as a complication at the adjacent level secondary to the rigid fixation.”
We want to stress this point too: People benefit from this surgery, this article is for the people who don’t or maybe poor candidates for this type of surgery.
The learning point of this research is all about the curve of the neck
- 70 patients undergoing surgical treatment for adjacent segment disease after anterior cervical decompression and fusion.
- Surgery for adjacent segment disease was performed after an average period of 32 months from the primary Anterior Cervical Discectomy and Fusion.
- Adjacent segment disease occurred after single-level ACDF in 54% of cases, most commonly after C5/6 fusion (28%).
- Risk factors for adjacent segment disease were found to be preexisting radiological signs of degeneration at the primary surgery (74%) and bad sagittal profile (the curve was bad) after the primary anterior cervical decompression and fusion (90%).
CONCLUSION: Adjacent segment disease occurred predominantly in the middle cervical region (C4-6); especially in patients with preexisting evidence of radiological degeneration in the adjacent segment at the time of primary cervical fusion, notably when this surgery failed to restore or maintain the cervical lordosis.
The curve of the neck will be discussed further below
The surgery to fix the surgery. Revision and more fusion is no easy fix
The removal of implants secured through the endplates of adjacent vertebral bodies
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.(5)
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 vertabra).
- 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.
- 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.
Patients with cervical instability are getting surgeries that cause more instability and deformity
Doctors at South Korea’s Pusan National University published this research in the Journal of Korean Neurosurgical Society.(6)
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:
The quick points:
- Thoracic spine involvement: Prior to Anterior cervical discectomy and fusion doctors should examine the T1 slope (for the correct or incorrect position) and C2-C7 sagittal vertical axis (this is a measure to determine if the spine is “plumb” in a straight line and 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.
- 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 the correct or incorrect position).
Surgical correction of the cervical spine curve during fusion surgery. Does it help? Why doesn’t it help?
In our non-surgical regenerative medicine injection techniques we recognize that to help the patient who sufferers from chronic neck pain, we must address and correct problems of the curvature of the cervical spine to achieve the best results. Surgeons also look at the curvature of the spine and its correction as a possible aid in helping their patients.
In December 2018 in the medical journal Therapeutics and Clinical Risk Management, (7) surgeons asked: “Is correction of segmental kyphosis necessary in single-level anterior cervical fusion surgery?” Here is how they answered that question:
- They examined 181 patients (99 males and 82 females) who underwent single-level ACDF surgery.
- There were 32 patients in the non-correction of curve group and 149 patients in the correction of the curve group.
- Surgical correction of segmental kyphosis in single-level cervical surgery contributed to balanced cervical alignment in comparison with those without satisfactory correction. However, the researchers could not demonstrate that the correction of segmental alignment is associated with better recovery in clinical outcomes.
What does this mean? It means that fusion is a complicated surgery and the impact post-surgery effects the natural movement of the neck even when the natural curve of the spine is restored. Let’s go back to this study. The researchers focus on disc height at the fusion level.
- “On the basis of our general practice, we recommended that the restoration of disc height in the index level is essential to correct segmental angle. However, risk factors for progressive cage subsidence, such as endplate excessive resection and oversized cage insertion with excessive distraction, should also be avoided during surgery”
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.
If you have a question about options to Anterior Cervical Discectomy and Fusion, you can get help and information from our Caring Medical Staff.
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