A large majority of individuals will have surgery of the spine and have success following their surgery. In fact, the overall success rate associated with spine related surgeries is around 90%. Unfortunately, there are a small percentage of spine surgeries that can fail. This is often referred to as failed spine surgery syndrome-neck area (also, failed back surgery syndrome). When spine surgery results are not what they should be, a new examination needs to be completed to find out the source of the continuing symptoms. One the cause has been confirmed, treatment for a failed spine surgery can be recommended.
Incomplete or recurrent compression of a nerve has occurred
One reason why failed spine surgery syndrome may exist, is due to an incomplete or recurrent compressed nerve of the spine. Decompression surgery is used to relieve pain in the neck, arm, shoulder, buttocks and leg. It it sometimes accompanied by a fusion surgery, but not always. If leg pain, arm pain, buttocks pain, or posterior shoulder pain is still present after surgery has taken place, or is relieved only temporarily after surgery, the nerve may not be fully decompressed or may have developed recurrent compression.
An example is a microdiscectomy for disc herniation. A patient may feel pain relief for about three weeks and then return of pain could indicate a recurrent disc herniation. Another example is a foramenotomy for the neck or lower back. A complete decompression will yield pain relief but if the vertebral level collapses after the decompression, the nerve will be compressed again and the pain will recur. An MRI of the neck should reveal this condition.
Failed cervical fusion surgery does happen at times. When fusion surgery fails, it essentially means that the bones failed to unite. When this occurs, it is referred to as pseudoarthrosis or “false joint’. The CT scan (on a 64 slice or greater scanner) and the flexion-extension x-rays are the mainstay to diagnose a pseudoarthrosis.
Pseudoarthrosis, while uncommon, can occur even in the best of circumstances (healthy patient, excellent surgeon, etc.). In certain, unique circumstances, the failure rate can be higher. Instrument fixation of the two bones to be united using metal rods, screws and/or plates is crucial to prevent motion. Motion prevents the bone cells from uniting the two surfaces. A construct that is flexible or weak can contribute to pseudoarthrosis.
A very important part of fusion surgery is the preparation of the graft bed or the bone surfaces so that nothing impairs the fusion. When the surgical area is not prepared properly, the fusion could fail.
The choice of graft materials is important. Use of allograft (donor bone) has a lower fusion success rate than autograft (your own bone). The use of bone morphogenic protein can significantly increase the fusion rate and the speed to fusion under the right circumstances. The use of PEEK spacers (plastic spacers) can be useful or detrimental depending upon the circumstances.
In correctly chosen cases, surgical repair can remedy the problem.
The wrong level of surgery is performed
In some rare situations, the wrong level of surgery is performed. This occurs because while the lumbar spine, thoracic sine, and cervical spine each have their own set of vertebra, most of them look the same. To identify these vertebra, careful observation of the anatomy of the spine from the intraoperative X-rays need to be performed.
There are many factors that can make vertebral levels appear distorted. Some patients have congenital anomalies that can put the count off in determining levels. Parallax of the image, very large body habitus making visualization difficult, poor x-ray technique and malfunction of equipment can occur to conceal the levels. Hopefully, these errors are caught in the operating room. If the surgery was not a success leading to a failed spinal surgery, a new MRI or CT scan can reveal the error of the incorrect level.
Neuropathic pain is present but is not recognized
Neuropathic pain is the most common surgical diagnostic dilemma that spine surgeons face. This pain after neck surgery is pain generated as a result of internal injury to the nerve root. This condition occurs from compression or stretch of a nerve. Diagnosis can only be confirmed by a successful surgical decompression with continued nerve pain and no further compression based upon a new post-operative MRI.
Before the initial surgery, a physical examination can typically identify the nerve involved. Imaging (X-ray, CT scan or MRI) will confirm the nerve compression. A nerve root block will even relieve the pain generated by the injured nerve. A successful surgery to decompress the nerve can be performed. A post-operative MRI will note a successful surgery where the nerve is free from compression. In spite of all of this, failed back surgery syndrome symptoms can persist.
This is an unfortunate case of neuropathic pain. The nerve was damaged by the original compression (herniated disc, lateral recess or foraminal compression) and the surgery successfully decompressed the nerve but the nerve itself did not heal.
Injections for spine pain can temporarily relieve the pain, as even an injured nerve will stop pain conduction under the proximity of a numbing agent like Lidocaine or Marcaine.
Following a failed back surgery, treatment of chronic pain management would include medications and neck surgery therapy and might include neurostimulation.
The initial diagnosis made was wrong
Though rare, if a number of potential pain generators exist and the history and physical examination does not lead to a specific diagnosis, an error of wrong diagnostic site can occur. A careful work-up will be needed once it is confirmed that a patient has failed back surgery syndrome (neck). The underlying condition using diagnostic injections can make the proposed surgical success rate higher. For example, a nerve could have been compressed at one level but not causing pain and at another level the painful pinched nerve is not recognized and not surgically addressed.
The original spine surgery was not performed perfectly or correctly
Sometimes during surgery, problems can occur that will result in spine pain even after the surgery has been completed. An inadvertent tear of the dura could expose nerve roots that can be damaged by subsequent rough handling. Dural leaks in the spine are rare, but can occur. A screw could be placed in a position that can irritate a nerve and cause pain in the leg or arm. Fusion failures leading to failed back surgery can occur from incomplete preparation of the fusion surfaces, improper placement of graft or of the wrong choice of graft material.
MRI and CT scans can potentially reveal some of these problems and the use of an intraoperative CT scan (the O-arm- see website) and intraoperative monitoring can prevent some of these errors.
The patient did not listen to or was not given the post-operative expectations (expectations too high)
Certain spine surgeries come with limitations that need to be understood and abided by. Fusion of the lumbar spine does typically relieve pain but does not commonly relieve all pain. Pain is typically reduced by about 2/3rds. If the patient does not understand that fact and is disappointed regarding the results, he or she might not have been educated sufficiently and expectations were too high. For example, while a one level fusion of the lumbar spine comes with no restrictions, a two level lumbar fusion has restrictions of impact and load. Three levels and more have further restrictions. Not following these restrictions can possibly cause further degeneration at levels higher in the spine.
The patient did not follow immediate post-operative restrictions (smoking cessation, activity restriction, activity overstimulation)
While failed spine surgery syndrome (neck) doesn’t happen often, when it does, it’s important to look at each and every cause. There is a responsibility that the patient needs to embrace to undergo spine surgery. Patients need to quit smoking as the nicotine in tobacco retards fusion cells. Patients that do not listen to restrictions or go back to hard work/ lift and bend too soon after lumbar fusion can disrupt the healing of the bone cells. Patients that mountain bike or ski immediately after cervical ACDF can reduce the chance of healing.