The neck is much simpler in terms of decision-making and surgical approaches than the lumbar spine. In my practice, procedures, such as cervical reconstruction surgery, is hardly ever performed posteriorly in the neck apart from for some very specific conditions, which are rare. The main reason for this is that no minimally invasive system exists for the posterior column of the neck, and anterior surgery in the neck is so successful at treating almost all conditions. This page assumes you have read The Spine - Basic Anatomy and Mechanics page, and the Causes of Back and Neck Pain page.
Anterior Cervical Surgery
All levels in the neck, from C2/3 down to C7/T1, can be accessed through a small 4-5cm incision (2-3cm for only 1 or 2 levels) on the front of the neck just to the side of your throat. It sounds a bit barbaric, but a small incision here is only a few centimeters away from the discs in your neck and no significant muscles need to be cut to get there. Modern retractors, efficient light sources, gentle instruments and image guidance (x-rays and computer navigation) all mean that the surgical footprint in cervical reconstruction surgery is small. The results of reconstructing the cervical spine are generally excellent and patient satisfaction is higher than lumbar spine reconstruction.
Like the lumbar spine reconstruction, cervical reconstruction surgery, can use fusion technology or disc replacement technology. Total disc replacement surgery in the neck has recently become accessible in Australia due to the lobbying of the government by the Spine Society of Australia.
Figure 1 (below) is a sagittal CT Scan showing a slice through the middle of the cervical spine with very bad disc disease at C5/C6 and C6/C7 motion segments. You can see how straight the spine is – almost all of the lordosis is lost. Most of the lordosis of the cervical spine is carried between C4/5, C5/6 and C6/7 and these are the 3 motion segments, which deteriorate most commonly.
The bony skeleton has a peculiar response to degeneration in joints, which leads to a lot of symptoms. Anyone with osteoarthritis of the hip or knee will be familiar with the term osteophytes. Osteophytes are areas of new bone formation (red arrows on right) that the skeleton lays down in order to combat the instability created by degenerate joints. This happens in the joints of the fingers, knees, hips, wrist spine – everywhere that moves and bears load if it degenerates. In a lot of areas these osteophytes are quite benign, but here in the front of the neck they can interfere with swallowing. Right behind the vertebral bodies is the spinal cord and if osteophytes form here the cord can get damaged (myelopathy), which is a very serious condition.
The axial CT scan shows a spicule of bone – again, an osteophyte – this time protruding backwards into the neuroforamen causing severe arm pain.
Figure 2 (below) is an MRI scan of a patient with at least 3, possibly 4, levels of disc disease. On this MRI you can see that not only has the cervical lordosis been lost but the spine has tipped forwards and become kyphotic around the degenerate segment. The discs at C4/C5 and C5/C6 are grossly collapsed and the spinal cord behind (red arrow) is in danger of becoming myelopathic (cord damage).
In Figure 3 (below) the white arrow points to the base of the brain just to give you a reference point. The disc below C7 looks normal – nice healthy, white, nucleus and good height. The disc above C3 looks normal. The discs at C3/4 and C6/7 have lost the signal of the nucleus and starting to show signs of collapse but nowhere near as deranged as the middle 2 discs. When discs are as bad as the middle two, they can only be reconstructed with a fusion. If the discs on either side required reconstruction to get on top of the patient’s pain, this could be done with a moving prosthesis.
Placing a moving prosthesis as part of the cervical reconstruction surgery when so many levels need to be addressed is very important to preserve motion and prevent the degenerative cascade spreading to other discs. Unlike the lumbar spine however, total disc replacement in the neck does not have the same power to restore lordosis as fusion technology. But, also, lordosis in the cervical spine is much less critical than in the lumbar spine and newer disc replacements like the CP-ESP can restore lordosis very well if used correctly.
Provided are x-rays of the neck of patients who have undergone multi-level cervical reconstruction surgery using fusion technology. Figure 1 (below) shows how levels have been reconstructed. You can see how the disc spaces have been restored to their original height and the segment is normally lordotic.
Figure 1 (below) shows red arrows pointing to a marker on the back of the fusion cage so that we can see how far away from the spinal cord the cage is – obviously very important to know this. The screws fix the cage into the vertebral body above and below so that it can't move. The cages are filled with a bone graft substitute, which turns into bone over a period of a few months thus fusing one vertebral body to the other.
Figure 2 (below) shows an x-ray image of a patient that has had cervical reconstruction surgery on 3 levels, underneath a very old fusion performed many years before (by another surgeon). Again, you can see how each level has been restored to its original height and lordosis is normal.
Restoring the lordosis with cervical reconstruction surgery significantly helps with the headaches of DDD in the neck by taking pressure of the greater and lesser occipital nerves – see the Causes of Back and Neck Pain page. If you are a chronic sufferer of these headaches, you can get the same kind of relief by lying down with a soft towel rolled up under your neck. The towel is giving you back your lordosis and slowly the headache should diminish. If it doesn't then the headache may well be coming from other areas.
Figures 6 and 7 (below) are of a patient of mine who has had cervical reconstruction surgery on 2 levels using a hybrid of fusion at one level and total disc replacement at the level above. Cervical total disc replacement is a very successful method of treating milder degenerative conditions. Preserving motion in the spine helps prevent the spread of degeneration to other adjacent discs. You can see on these flexion and extension x-rays how the prosthesis moves equally with the discs above.
Very recently a study was performed that analysed the combined results of 4 class 1 studies from FDA trials in the USA. This has shown clear superiority of total disc replacement over fusion in the neck, and the authors (Paul McAfee et al.) recommended that it be the standard of care over fusion technology.
Risks of the Procedure
Unlike the lumbar spine, the spinal cord itself runs behind the vertebral bodies in the neck. If the cord is damaged during cervical reconstruction surgery, then paralysis can result. This is extremely rare and probably represents the worst of all possible outcomes. If the risk of this was high or even moderate, no-one would perform cervical reconstruction surgery. Thankfully modern techniques, image guidance, good light sources and well-designed instruments make this practically an unheard-of complication.
Apart from the general risks associated with any surgery, cervical reconstruction surgery risks damage to any structure that needs to be moved out of the way in order to perform the task in hand. These structures include:
- The oesophagus (food pipe).
- Trachea (windpipe).
- Carotid artery (supplies blood to the brain).
- Laryngeal nerves (supply the voice box).
- Autonomic nerves (nerves that operate outside of conscious control to the face muscles, salivary glands, eyes and eyelids, sweat glands, diaphragm amongst others).
- Muscles of the neck.
Significant damage to any of these is disabling but very rare. All patients however, for a few weeks, have some difficulty swallowing, lose their voice a little, and experience some bruising in the area. This mild syndrome lasts usually only a short period of time and has no bearing on the final result.
The results of reconstructing the neck are generally more predictable and more satisfying than reconstructing the lumbar spine with patient satisfaction scores over 90% provided no complications occur.