Cervical disc degeneration, tear and prolapse
Anatomy
The cervical (neck) spine has 7 pieces (vertebrae) whose bodies are stacked like building blocks. The disc acts like a cushion or shock absorber between the bodies of the vertebrae. The disc is like an onion with layers on the outside (annulus) which if torn can be painful. In the centre of the annulus is the nucleus, which is like crab meat. The disc dries out with degeneration (meaning wear and tear that occurs with getting older and which may be accelerated by injury).
Pathology
Disc degeneration is best seen on magnetic resonance imaging (MRI) but usually doesn't cause any symptoms. However, sometimes disc degeneration can cause pain which can be due to annulus tear, mechanical failure or toxic ("poisonous") chemicals caused by breakdown of the disc. Disc degeneration may occur with or without reduction of disc height. Rupture of the annulus with outpouching of the nucleus is referred to as a "ruptured disc", "herniated disc", "disc prolapse" or "slipped disc". The fresh prolapse is initially well hydrated (like a grape) but with time it usually shrinks due to dehydration (like a sultana). This is why most disc prolapses improve without surgery. As we get older the spine often forms bony spurs (called osteophytes). This condition is called osteoarthritis, osteoarthrosis or spondylosis and is the commonest form of arthritis in our community. Surprisingly, these bony spurs do not usually cause any neck pain but they can grow and press on a nerve in the spine to cause arm pain (brachial neuralgia), or on the spinal cord to cause weakness and/or numbness in the arms and legs, as well as difficulty with bladder control.
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Symptoms
The nucleus can burst through the annulus to press on a nerve to cause pain, tingling and/or numbness down the arm, which is called brachial neuralgia. Sciatica is the equivalent term in the leg. Disc disease can cause pain at the back of the neck directly or may cause "referred" pain, meaning pain from the cervical spine which is felt elsewhere - into the forehead or back of the head, the shoulder(s), shoulder blade(s), between the shoulder blades, or into the arm down to the elbow. Brachial neuralgia is also a type of referred pain due to pressure producing a painful nerve. A much more serious problem is if the disc ruptures directly backwards to place pressure on the spinal cord. This can result in weakness and/or numbness in the arms and legs, as well as difficulty with bladder control.
Treatment
The best treatment is prevention - i.e. taking good care of your neck. Pressure in the disc is least when you lay flat, higher when you stand, and highest when you bend your head forwards (flexion). Therefore, you are advised to minimise neck flexion - e.g. when eating meals, reading, working on the computer or particularly when sleeping. You are therefore advised to sleep on a single flat pillow or ideally have a therapeutic pillow such as a "bow tie" pillow or one which supports the back of your neck by placing the neck in some extension (bending the head slightly backwards). A neck brace can be of benefit for pain relief in the short term if there is a lot of neck pain which is worsened by movements. Generally you would be advised not to have a brace too long because your neck muscles can become weaker and lazier. Repetitive neck movements - e.g. when driving a car or freestyle swimming - should be minimised.
Because most cases of brachial neuralgia will settle with time, the aim of treatment is to manage the pain while waiting for this natural improvement. Most times brachial neuralgia noticeably improves over about 3-6 weeks.
You can often predict the time course of improvement by charting a graph of pain versus time:
In the meantime, treatment by a physiotherapist is valuable and recommended. Traction can be particularly helpful to open up the narrowed tunnel that the pinched nerve is in. Brachial neuralgia is less likely to settle if the pain has come on gradually rather than rapidly, if it has been present for more than several weeks, or if there is a large disc prolapse on X-rays. Occasionally, benefit can be obtained with a nerve root sleeve cortisone injection. Surgery is generally a last resort option.
The three reasons why you might need surgery are:
1. the pain is too severe to cope with in the short term - e.g. you need hospitalisation
2. the pain is persisting for too long, interfering with your quality of life
3. if you have significant muscle weakness from pressure on a nerve, particularly if there is evidence of pressure on your spinal cord
Generally, if your problem is #1 or #2, it is basically your decision whether surgery is needed; you should not be pushed into a neck operation if your problem is purely pain. However, if you have problem #3, your surgeon may advise surgery because the nerve or spinal cord pressure is too great and they may not recover if the pressure is not taken away.
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Nerve Root Sleeve Injection (NRSI)
NRSI means an injection around a nerve root in the spine. Usually the injection consists of local anaesthetic to give immediate but short-lasting pain relief from half to several hours, mixed with a steroid. The steroid is an anti-inflammatory drug which reduces swelling and which may take several days to have its full effect.
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The effect of a NRSI usually lasts days to a few weeks, but may be very brief or need help for months.
NRSI can be ordered by your General Practitioner or specialist. NRSI is usually done using a CT scan, in which case a radiologist doctor (radiologist) gives the injection. Otherwise it is given by a pain specialist, in which case it is done in an operating theatre under x-ray control, often with the patient sedated.
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NRSI is used for two main reasons:
Therapy - to help severe arm pain (brachalgia) or leg pain (sciatica) from a compressed nerve in the spine, usually from a disc prolapse or bony compression. Most times these pains will settle over a number of weeks. NRSI is one way to help relieve the pain while the condition naturally improves. NRSI can be very helpful for the severe pain that might otherwise require surgery. For this reason it is helpful in elderly or frail patients on whom we would wish to avoid surgery.
Diagnosis - it may not be clear which nerve is causing the pain. For example, arm pain going into the fingers may be due to C6, C7 or C8 nerve compression. X-rays may not be clear as to which nerve is compressed. In these cases it can be helpful to perform a NRSI to see if the pain is helped by the injection. For example, the doctor may suspect that C7 nerve is the problem. If a C7 NRSI helps the pain, even for a few minutes, then this indicates that C7 is the problem. This is helpful if the surgeon is considering which nerve to operate upon.
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Complications from NRSI
Complications are very rare. However, sticking a needle into any part of the body must have a risk, particularly infection. Rarely a nerve may be injured if it is injected into, instead of next to. Very rarely a cervical (neck) NRSI may travel into the blood supply of the spinal cord and cause spinal cord injury. I have never seen this happen.
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Cervical disc surgery
Surgery for cervical disc disease involves one of three possible operations:
2. anterior cervical discectomy and fusion
3. artificial disc (A.D.) replacement
Foramenotomy
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This is performed from behind. Foramen means a window so this operation involves the creation of a window performed between two vertebrae. The foramenotomy is made over a nerve root to allow the nerve to be freed up. The nerve may be trapped by bony overgrowth or spurs (osteophytes) or there may be a disc prolapse which can be retrieved from behind. Foramenotomy may be done with an endoscope or down a microscope, the latter called microdiscectomy.
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Following cervical foramenotomy:
- You are encouraged to walk on the day after the surgery, and not uncommonly on the day of the surgery.
- You may find that a soft collar is helpful for support and pain relief in the first couple of weeks. However, you are encouraged to do without it as early as possible so as to prevent your neck muscles becoming lazy and weak because they are not being so active.
- Please note that your neck is quite stable and you are encouraged to try to mobilize it as soon as possible, within the limits of discomfort. At least twice a day you should do the following exercises: bend the neck forward and backwards, sideways to the left and right, and rotating (turning) to the left and right. Otherwise your neck may become stiff.
- There are usually no stitches to be removed - your stitches are buried and will dissolve with time. You can shower with a dressing on for the first two days after surgery. Generally I advise removal of the large dressing 48 hours after surgery, leaving the paper strip (Steri-Strip) on for another 24 hours. After 72 hours postoperatively, the wound should be left totally exposed - i.e. you can shower with the wound exposed. If there is some persistent oozing, a dressing will be required for longer. The wound should not be soaked (as in swimming or sitting in a bath) for one week postoperatively.
- After surgery it is not uncommon to have various aches and pains in and around the wound and shoulders. These should improve with time. For the first two weeks postoperatively, your arm pain may return because of nerve swelling. This recurrent pain usually resolves within two weeks. If the pain is severe, please contact me so I may consider prescribing dexamethasone (a strong anti-inflammatory steroid drug).
- It is very helpful to have seen a physiotherapist before your surgery and even more important to see one postoperatively. You can receive heat, ultrasound and massage, plus information on exercises and how to move and how to build up your neck muscles long-term in order to help best maintain the strength of your spine.
- You will probably find it too uncomfortable to drive in the first couple of weeks so get someone else to drive you.
- Your neck will never be normal so it is important to take good care of it.
Anterior cervical discectomy and fusion
This is performed through the front of the neck. The entire disc needs to be removed either to remove the diseased disc or to get to the ruptured portion of the disc which is at the back. So that the disc space doesn't collapse, a bone graft is placed in the disc space. This may be a block of bone from the pelvis bone or, more commonly nowadays, a hollow plastic cage which is filled with pieces of bone. In either case the two vertebrae will knit (fuse) within 6-12 weeks. I always place a plate across the disc space, screwed into the two vertebrae, to make the construct immediately solid. However, neurosurgeons do not do this and will place their patient in a collar. This approach is less painful than going from behind but does have its drawbacks - there is a small risk of permanent hoarseness (which usually can be fixed by an Ear, Nose and Throat surgeon) and there usually is temporary difficulty swallowing because the voice box and throat need to be pushed to one side.
There is absolutely no doubt that smoking reduces the success rate of fusion. Smoking interferes with the development of new blood vessels that are essential for developing new bone.
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Artificial disc replacement
This is the same operation as anterior cervical discectomy and fusion but a mobile artificial disc is placed in the disc instead of bone. We believe an A.D. will protect the adjacent disc levels from developing excess stress, as compared to fusion. We do know the chance of needing surgery next to a fused disc level is about 3% per year. We'll have to wait several years to see if A.D. does indeed protect the adjacent discs better than fusion. There are different brands of A.D. on the market - Prestige, P.C.M., Bryan and ProDisc-C.
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Following anterior cervical discectomy and fusion or artificial disc replacement:
You are encouraged to walk on the day after the surgery and not uncommonly on the day of the surgery.
Please note that your neck is quite stable and you are encouraged to try to mobilize it as soon as possible, within the limits of discomfort. At least twice a day you should do the following exercises - bend the neck forward and backwards, sideways to the left and right, and rotating (turning) to the left and right. Otherwise your neck may become stiff.
Everybody has some swallowing difficulties immediately after surgery. This is because your throat was displaced to one side in order to get to the spine. This usually resolves over a few days to weeks but rarely it can be permanent, in which case you will need to see a speech pathologist/therapist. Hoarseness is also rare following surgery but when it occurs it is usually with surgery at C6/7 disc because it is at this level that there is a major nerve to the voice box.
There are usually no stitches to be removed - your stitches are buried and will dissolve with time. You can shower with a dressing on for the first two days after surgery. Generally I advise removal of the large dressing 48 hours after surgery, leaving the paper strip (Steri-Strip) on for another 24 hours. After 72 hours postoperatively, the wound should be left totally exposed - i.e. you can shower with the wound exposed. If there is some persistent oozing, a dressing will be required for longer. The wound should not be soaked (as in swimming or sitting in a bath) for one week postoperatively.
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After surgery it is not uncommon to have various aches and pains in and around the wound and shoulders. These should improve with time. For the first two weeks postoperatively, your arm pain may return because of nerve swelling. This recurrent pain usually resolves within two weeks. If the pain is severe, please contact me so I may consider prescribing dexamethasone (a strong anti-inflammatory steroid drug).
It is very helpful to have seen a physiotherapist before your surgery and even more important to see one postoperatively. You can receive heat, ultrasound and massage, plus information on exercises and how to move and how to build up your neck muscles long-term in order to help best maintain the strength of your spine.
You will probably find it somewhat uncomfortable to drive in the first couple of weeks so get someone else to drive you. If you have had an artificial disc replacement, I do not allow you to drive until at least two weeks postoperatively.
Your neck will never be normal so it is important to take good care of it.
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Discography
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Discography is a test to see if one or more discs are causing pain. MRI can often identify an abnormal disc but it can be difficult to identify exactly which disc(s) is(are) producing pain. It involves a radiologist (x-ray doctor) or a pain specialist injecting one or more discs while you are awake. This is done under x-ray or CT.
You need to be awake so that you can report what, if any, type of pain the injection produces. Surprisingly, injection of a normal disc causes very little discomfort. Injection of a painful disc will reproduce your pain and can stir up the pain for some days. Discography would only be performed if there is a serious consideration of surgery to remove one or more painful discs.
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Cervical corpectomy
Like anterior cervical discectomy and fusion (ACDF), cervical corpectomy is performed through the front of the neck. Corpectomy means removal of the vertebral body, the major part of the cervical vertebra which looks like a building block. It is basically a long ACDF. Corpectomy is performed when two or more cervical discs need to be removed. For certain patients it is easier to remove two or more discs plus the intervening body or bodies. This is particularly true when there are osteophytes (bony spurs) behind the body and/or the disc space is narrow. By removing a cervical body there is a large area of exposure which is easier to work through rather than working down a narrow disc space.
Corpectomy is done for much the same reasons as an ACDF but usually when there are two or more disc levels associated with bony spurs pressing on the spinal cord or, less often, for tumours of the cervical spine.
As for ACDF, once a space has been created in the spine this space has to be filled so that the spine doesn't collapse. Usually a bone graft is taken from the iliac crest (bony pelvis) but occasionally a hollow metal strut is used and then filled with either your own bone or plastic cement (acrylic). Acrylic tends to be used in tumour cases. Whatever spacer is used, the entire construct is reinforced with a long plate and screws. Occasionally for long anterior fusions, a fusion needs to be added as a separate operation through the back of the neck. The longer the fusion, the more likely it is that a posterior fusion needs to added. Generally a posterior fusion is done when three or more cervical bodies have to be removed, equivalent to four or more adjacent disc spaces.
Postoperative management is the same as for ACDF with the single important difference that you must not drive until you have solidly fused. This usually is at least three months. You may be a passenger in a car but you should not drive because forceful neck turns may undo your fusion. Depending on the strength of the construct, you may need to wear a brace for several weeks.
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Laminectomy
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Laminectomy means removal of part or all of a lamina, at one or more levels in the spine (pictured to the left, where a C4 laminectomy has been performed).
The lamina is the back (or posterior) part of the spinal canal. The spinal cord ends at just below the junction of the thoracic and lumbar vertebral level. Therefore, the spinal canal contains the spinal cord in the cervical and thoracic spine, and nerve roots in the lumbar and sacral spine.
Pictured to the left is a left view of the cervical spine. The spinal cord is the vertical yellow structure.
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The most common reason to do a laminectomy is to decompress the squashed nerves in the lumbar spine, in a condition called lumbar canal stenosis. This is most common at L4/5 but is often at multiple levels.
The narrowing of the spinal canal is due to a combination of thickened ligamentum flavum (Figure 3) at the back (which connects the adjacent laminae), thickening of the facet joint capsules at the two sides, and bulging of the discs at the front.
Patients typically complain of pain and/or weakness and/or numbness/tingling in one or both legs whenever they stand or walk for too long, but are fine with sitting and laying.
Diagram to the right courtesy of and copyright to Apparelyzed, a spinal cord injury peer support group.
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| View of the spine, spinal cord and nerves from the left side. The orange structure is the spinal cord, ending at about the L1/2 junction. |
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In the cervical spine the most common reason to perform a laminectomy is when the spinal cord is being compressed by bony narrowing and/or thickening of spinal canal ligaments and/or bulging discs. This condition is called cervical spondylotic myelopathy. Patients experience difficulty using their hands, which may feel as though they are wearing gloves, and may also have difficulty with lower limb weakness.
Apart from decompression of nerves and the spinal cord, laminectomy is also performed to gain access to the spinal canal, e.g. for removal of tumours.
The picture to the left is looking at the spine from behind. The lower half of a lamina has been removed. The yellow structures are the ligamentum flavum (yellow ligament) which connects adjacent laminae.
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Facet joint disease
Each vertebra in the spine joins its neighbour via three joints - the large disc in the front and two small facet joints behind, forming a triangle of joints surrounding the spinal canal. The facet joints are also sometimes called zygapophyseal joints.
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The facet joints are most commonly affected by osteoarthritis (wear and tear arthritis). Facet joint pain can be felt over the affected joint but can also be referred - to the shoulder girdle, shoulder blade or arm in the case of the neck, or into the bony pelvis, hip or thigh in the case of the low back. It tends to be worse with extension of the spine (bending backwards).
Plain x-rays, CT or MRI scans can identify facet joint disease but sometimes the most sensitive test is a nuclear bone scan, which can identify facet joint problems when the other tests appear less obviously abnormal.
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Treatment consists of:
- pain killers as necessary
- glucosamine may be useful as for other joints affected by osteoarthritis
- physical therapy using local treatments (heat, ultrasound and massage) but particularly to learn to strengthen the supporting spinal muscles of the neck or low back - this builds up the body's own brace for the spine
- acupuncture can be useful
- facet joint injections can be very helpful. This can be done by a radiologist who injects cortisone and local anaesthetic directly into the joint or by a pain specialist who either injects the joint or else can block the sensory (feeling) nerves supplying the joint
- radiofrequency (RF) rhizotomy - if a facet joint injection is helpful, a much longer period of pain relief can be obtained by heating the nerves supplying the affected facet joint. This is performed by a pain specialist.
- surgery is rarely used for pure facet joint disease and pain. Usually surgery is reserved for when facet joints develop osteophytes (bony spurs) which press on the spinal cord or nerves. In the lumbar spine interspinous spacers or stabilizers can occasionally be used to reduce the movement and distract the painful facet joint. This has only been used in the last several years and requires further long-term study before it is accepted as a standard treatment, but it certainly seems to have a benefit. Facet joint disease is a contraindication to artificial disc replacement, which only replaces the disc, not the facet joints.
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Thoracic disc prolapse
Disc prolapse (TDP) in the thoracic spine is much rarer than in the neck or low back.
As opposed to the neck or low back, TDP tends to be chronic (meaning of gradual onset) because it tends to be calcified (full of calcium). TDP is commonly found on routine scans but rarely causes problems.
TDP becomes significant if it compresses the spinal cord. Symptoms are weakness or numbness/tingling in one or both legs.
Bladder function may be affected later, causing a frequent need to urinate.
The best investigation is an MRI scan (figure 1).
If there are symptoms due to spinal cord compression, surgery is almost always needed.
Surgery can be performed through the back or through the chest.
1) Thoracotomy means opening the chest. The lung is collapsed and the spine is directly visualized. Under a microscope, part of the affected disc is removed and the spinal cord is decompressed. Usually a small piece of rib is placed in the disc space and this is secured by a metal plate and screws.
2) Costotransversectomy means making a cut to the side of the spine at the back to approach the TDP and spinal cord at an angle. It may or may not be necessary to insert metal hardware for stabilization.
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Complications
The aim of surgery is to prevent damage to the spinal cord. There is a risk of injury to the spinal cord which varies from 1% or significantly more if the TDP is large. However, there is really no alternative to surgery.
1. paraplegia
2. infection in about 1%
3. spinal fluid leak from the wound
4 persistent wound pain occurs in up to 5% of thoracotomies.
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Risks of spine surgery
Infection
This may simply be an infection of the wound which requires some dressings, removal of a stitch and/or antibiotics. Deeper infection may require a return to theatre to drain the collection of pus. Infection may also affect the CSF (cerebrospinal fluid) around the nerve roots and spinal cord, which is called meningitis and requires hospitalisation and intravenous antibiotics, but is virtually always curable. Infection of an operated disc space or of bone often requires initial hospitalisation and intravenous antibiotics, and then several weeks or months of oral antibiotics, often supervised by an infectious diseases doctor.
Paralysis
Prior to surgery, there may already be some nerve or spinal cord damage causing muscle weakness. A nerve or the spinal cord may be already squashed and at increased risk of being injured because of the manipulation needed to try to free the nerve or spinal cord. Nerve or spinal cord damage may also affect control of the bladder and bowel.
Cerebrospinal Fluid (CSF) leak
The brain and spinal cord are surrounding by CSF, which looks like water and is salty. CSF leak occurs if the outermost layer of the meninges (= the three outer coats of the brain and spinal cord), called the dura, is not completely closed watertight. CSF can leak through the dura and then through the skin and this will need to be fixed, otherwise there is a risk of meningitis. Just like a leak in the roof, there only needs to be a small hole to let water through and this can sometimes be troublesome to repair, but is virtually always correctable. Repair may require a simple skin stitch, a spinal drain tube inserted in the low back to drain the CSF via another route, or a trip back to theatre.
Deep Vein Thrombosis (DVT)
DVT means a blood clot developing in the leg. The patient may notice a painful swelling of the calf but a DVT may not be noticed. This clot may dislodge and travel to the lungs and heart to block the circulation, which is known as a pulmonary embolus (PE). A PE can be fatal and usually occurs about 1-2 weeks after surgery, or 1-2 weeks after a patient has commenced being confined to bed. Increased risks for DVT and PE are bed rest, prolonged surgery, obesity, cancer, past DVT, paralysed leg/s and heart failure. To prevent DVT, the patient is encouraged to get out of bed as soon as possible, usually the day after surgery. Before this, the patient can wiggle the toes and move the legs around in bed as soon as wakening from the anaesthetic. Prior to surgery, the patient will have elastic stockings put on. While in surgery, the patient has leg pumps to improve the circulation. In most cases prior to surgery, blood thinning injections are commenced - I like to use Clexane injections into the stomach each morning until discharge from hospital.
Wrong spinal level
This sounds unbelievable but it can be easily done. Spine surgery can be like trying to find where your car has been parked in a multilevel car park - all the levels and areas look similar. There are 33 bones in the spine and they mostly look similar. They don't have labels on them telling the surgeon which level is which. All patients vary and different anatomy can be confusing to the surgeon. This is particularly the case when a patient has an L5 vertebra joined to the sacrum. In this case some doctors will call the lowest disc L4/5 while others call it L5/S1 or, even more confusingly, L5/6. Don't worry if you don't understand this - this is for the surgeon to work out. Perhaps a simpler example is that some people have 11 or 13 instead of 12 ribs. It then becomes confusing as to what you call the next lumbar vertebra - T12 or L1.
Death
Death on the operating table is very rare. Death can occur with any surgery and usually occurs after the operation. The most common reasons are myocardial infarct (heart attack) due to the stress of the surgery, a rare reaction to a drug (anaphylaxis) or pulmonary embolus. I mention the risk of death or paralysis (stroke) to any patient having an operation, no matter how minor the procedure.
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