There are situations that call for necessary cervical (neck) surgery, circumstances when surgery depends upon specific situations and times when surgery is not indicated. Identification of these temporal states is not that difficult when certain rules are applied.
What are the general indications for neck surgery?
- Nerve compression that leads to motor weakness.
- Nerve pain that is not tolerated or necessitates unacceptable reduction of activities due to pain.
- Degenerative disc or facet disease that causes intolerable neck pain.
- Deformity that is progressive/ Instability.
- Spinal cord compression possibly leading to Myelopathy
Nerve compression that leads to motor weakness
Nerve compression that leads to motor weakness is generally a surgical condition. Compression of a nerve can lead to pain but does not always have to be accompanied by weakness. This pain and numbness is not necessarily a surgical indication by itself (see next section below for further information).
If there is weakness of a major motor group (specific group of muscles) from nerve compression, more often than not surgery is indicated. The reason has to do with the integrity or relative “toughness” of the motor nerves.
Pain, numbness and paresthesias (pins and needles) involve the sensory, nociceptive and proprioceptive (location sense) components of the nerve. These portions of the complete nerve root are very sensitive to compression. That is, even slight compression or irritation will lead to symptoms. Conversely, being so sensitive they also have good ability to recover with therapy and injections without surgery. In addition, even some permanent minor deficits in these nerves (remaining skin numbness or pins and needles) are typically easily tolerated.
The motor nerves have a much greater capacity to resist compression than the sensory nerves. It therefore takes significant compression of the motor nerves to block function. Unfortunately, this also means that motor nerves have a poorer capacity to recover or regenerate than the sensory nerves.
The best chance for motor strength recovery is with surgery to decompress the nerve (microdiscectomy or foraminotomy). There still is a small chance that with surgery, the muscle strength will not recover but with surgical decompression, the chance of recovery is much greater than without surgery.
The specific nerve involved in motor weakness does seem to make a difference regarding the chance of recovery. The C5, C8 and T1 nerves tend to be more sensitive to compression and demonstrate less ability to recover after surgery. Surgery to decompress those nerves should be considered sooner than later. The C6 and C7 nerves are somewhat more forgiving and may have a better chance of recovery if surgery is delayed for some reason.
Nerve Pain that is not tolerated or necessitates unacceptable reduction of activities due to pain
This category is the most common reason patients choose to undergo surgery in the cervical spine. Disc herniations or nerve compression from bone spurs can cause arm pain. Back of the shoulder pain (trapezius pain) is common with moderate or intermittent nerve compression. Symptoms may include pain, numbness or paresthesias (pins and needles). Compression of the sensory nerves leads to numbness. Compression of the nociceptive nerves leads to pain. Compression of the proprioceptive nerves leads to paresthesias.
These nerves are highly sensitive and even a small amount of compression will aggravate them. Pain can be substantial and paresthesias can drive some patients absolutely crazy. Nonetheless, without motor weakness, there is generally no need to immediately rush to surgery unless the pain is intolerable or the patient fails conservative treatment including injections and mediations. The reason is that these nerves being so sensitive also have good capacity to recover.
In the clinic, the three to six month rule for surgical indications is generally used for these types of patients. If the individual has made at least 50% improvement within three to six months (or has no desire to undergo surgery), then continuing conservative care is the determined path.
If the pain has not substantially improved in this period of time or pain relapses occur commonly, surgery may become the treatment of choice. Patients seem to do better if surgery is performed in the first three to six months than if surgery is put off until after six months of symptoms.
There are patients who at rest have little pain but with certain activities, develop incapacitating pain. This is dynamic pain caused by gravity’s effect on an unstable vertebral segment. Without load on the spine, the nerve root can tolerate the narrowed lateral recess or foramen. With loading however, the increased compression causes further compression and significant increase in pain precluding the desired activities. Extension (bending the head backwards) narrows the foramen. Activities that cause extension, (bike riding, swimming, tennis, basketball and even computer work) can aggravate the pain.
If the inciting activities can be avoided to the satisfaction of the patient, surgery will not be necessary. For example, if the patient can switch from cycling to hiking and the arm or shoulder pain is alleviated, surgery is not necessary. If however, the pain is associated with a non-negotiable activity restriction (a professional ball player who cannot shoot the ball or an auto mechanic who cannot look under the hood), surgery will be indicated.
There is a subset of patients that show up on my doorstep with severe pain from an acute disc herniation. They lie moaning, curled up in the fetal position on the exam table grabbing their arm or are seen in the emergency department on a stretcher after taking substantial amounts of pain medications. These patients need surgery to relieve the unrelenting nerve pain even without motor weakness.
There is a subset of patients that have permanent injury to the sensory and pain nerves from prolonged exposure to compression. Surgery will decompress the nerve but not relieve the damage already incurred (see chronic radiculopathy).
Degenerative Disc Disease or Facet Disease That Causes Intolerable Neck Pain
Neck pain from degenerative disc or facet disease can be an indication for surgery. Cervical pain may be incapacitating but it is not generally life threatening. This pain tends to wax and wane in many patients. When then is neck pain an indication for surgery?
Patients with incapacitating neck pain may be surgical candidates. These patients must have been proven to have non-manageable pain (failing therapy and medication programs) and this pain must affect the patient’s lifestyle. If a patient can acceptably modify his or her lifestyle to reduce the pain to a tolerable level, surgery would not be indicated.
If however, the lifestyle change is not modifiable (a professional baseball player that cannot shoot a ball or a mechanic that cannot get under the dashboard) or the modification is not acceptable (a patient cannot participate in recreational activities without substantial pain), surgery might be indicated.
First, prior to surgical consideration, neck pain patients have to complete a thorough rehabilitation program associated with ergonomics (modifications in lifting and loading the spine). If the modification of activities is ineffective, other therapies may be instituted including epidurals and medications. If these treatments fail to relieve symptoms, surgery can be contemplated.
Neck pain has to be present for more than three months and most patients considering surgery will have had at least six months of neck pain. A surgical workup then can ensue. This workup might consist of imaging (MRI, CT and X-rays), diagnostic nerve blocks and possibly even discograms. If the pain generators can be identified, a surgical plan is formulated. Normally, the surgery is a fusion of the painful segment or segments. Artificial discs allow for neck motion and prevention of painful motion is normally the goal of a surgical outcome.
Certain disorders may cause back pain that do not specifically involve degenerative disc disease. Examples are degenerative spondylolisthesis with associated instability. These disorders also respond to fusion.
After a one level successful fusion, the patient can return to almost all sports and activities. If two levels are fused, the post-operative restrictions are somewhat greater. If three or more levels are fused, the patient has to understand that fusion and pain relief is being traded for spine stiffness and the post-operative restrictions are more stringent.
Deformity that is progressive/ Instability
A spinal malalignment can be stable or progressive. Kyphotic angular curves and even individual segmental collapses can progressively deform over time. If the angulation can be predicted to continue or is observed over time with serial X-rays to progress, surgery is indicated. This is to prevent problems with correction in a curve that will progressively become larger over time.
A degenerative slip (spondylolisthesis) may progress and be predicted to continue to slip. This is an indication for surgery as progressive instability can put the spinal cord at risk.
Cord compression and Myelopathy
The spinal cord is a central nervous system component and is very sensitive to compression. Injury to the cord is generally permanent so cord protection is imperative. The spinal canal in the neck is normally wide enough to accommodate the cord with room to spare. Certain patients may have a congenitally smaller canal and many patients can develop canal narrowing from typical degenerative changes. This can lead to spinal cord compression. Dysfunction of the spinal cord then leads to myelopathy.
This myelopathic cord compression may lead to bowel and bladder malfunction as well as possible motor deficits. Walking and balance become difficult and simple tasks with hand manipulation (buttoning a button or signing your name) become more problematic. Other symptoms also predominate (see section regarding myelopathy on this website).
If there is cord compression causing myelopathy, surgery is required to decompress the cord and protect against further injury. If there is cord compression without myelopathy, a long look at the future needs to be contemplated.
Having a narrowed spinal canal places the spinal cord at risk for injury. The spinal canal actually changes in volume with flexion and extension of the neck (bending forward and backwards). Flexion opens the canal and extension narrows it. If a fall occurs onto the front of the head, this action will force the neck into hyperextension which can injure the cord (central cord syndrome).
A change of activity can reduce but not eliminate the risk of cord injury. If you have cord compression without current cord injury and participate in sports such as skiing, horseback riding, biking (especially mountain biking), contact sports or any activity where a fall can cause significant neck motion, the risk of injury is present. Cessation of those activities can reduce the risk of injury but not eliminate it as even an auto accident can cause cord injury from a whiplash.