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What is an anterior cervical discectomy (decompression)
and fusion? It is abbreviated to ‘ACDF’, with each letter standing for:
Why might I need an anterior cervical discectomy (decompression)
and fusion? An ACDF is usually performed for one or more of the following reasons:
Surgery is usually recommended when all reasonable conservative measures (pain medications, nerve sheath injections, physical therapies, neck collars etc.) have failed. In cases of significant instability or neurological problems, surgery may be the most appropriate first treatment option. What exactly is wrong with my neck? Symptoms of neural (nerve or spinal cord) compression include pain, aching, stiffness, numbness, tingling sensations, and weakness. As spinal nerves branch out to form the peripheral nerves, these symptoms may radiate into other parts of the body. For example, cervical nerve root compression (pinched nerves in the neck) can cause symptoms in the shoulders, arms, and hands. Disorders that can cause nerve root compression include spinal stenosis, degenerative disc disease, a bulging or prolapsed intervertebral disc, bony spurs (osteophytes), or spondylosis (osteoarthritis of the spine). Commonly, two or more of these conditions are seen together. Intervertebral discs sit between each bone (vertebrae) in the spine. They act as shock absorbers as well as allowing normal movement between the bones in your neck. Each disc has a strong outer ring of fibres (annulus fibrosis), and a soft jelly-like central portion (nucleus pulposis). The annulus is the toughest part of the disc, and connects each vertebral bone. The soft and juicy nucleus of the disc serves as the main shock absorber. An annular tear is where the annulus fibrosis is torn, often the first event in the process of disc prolapse. An annular tear can cause neck pain with or without arm pain. A cervical disc prolapse (or herniation) occurs when the nucleus pulposis escapes from its usual position and bulges into the spinal canal, sometimes placing pressure on the nerves or spinal cord. In degenerative disc disease the discs or cushion pads between your vertebrae shrink, causing wearing of the disc, which may lead to herniation. You may also have osteoarthritic areas in your spine. This degeneration and osteoarthritis can cause pain, numbness, tingling and weakness from pressure on the spinal nerves and/or spinal cord. Osteophytes are abnormal bony spurs which form as part of the degenerative process or following a longstanding disc prolapse. This extra bone formation can cause spinal stenosis as well as intervertebral foraminal stenosis, resulting in compression of the spinal cord and/or spinal nerves. Patients with a painful deformity in their cervical spine may benefit from surgery to straighten and stabilize the spine. Deformity correction is often undertaken at the same time as a decompressive surgical procedure. As the neck is so flexible (it has to be to perform its usual functions), it is vulnerable to serious injury. Significant trauma can cause a fracture and or dislocation of the cervical spine. In a severe injury the spinal cord may also be damaged. Patients with a fractures and/or dislocations, especially with spinal cord damage, frequently require surgery to relieve pressure on the spinal cord and stabilize the spine. Instability of the neck may cause neck pain as well as neural compression. This may be the result of trauma, rheumatoid or osteoarthritis, tumour or infection. Instability frequently mandates surgical stabilisation. What are the alternatives to an ACDF?
What are the goals (potential benefits) of surgery? The rationale, aims, and potential benefits of an ACDF may therefore include:
Generally, the symptom that improves the most reliably after surgery is arm pain. Neck pain and headaches may or may not improve (very occasionally they can be worse). The next symptom to improve is usually weakness. Your strength may not return completely back to normal, however. Improvement in strength generally occurs over weeks and months. Numbness or pins and needles may or may not improve with surgery, due to the fact that the nerve fibres transmitting sensation are thinner and more vulnerable to pressure (they are more easily permanently damaged than the other nerve fibres). Numbness can take up to 12 months to improve. The chance of obtaining a significant benefit from surgery depends upon a wide variety of factors. Your neurosurgeon will give you an indication of the likelihood of success in your specific case. How Does Revision Surgery differ? The risk of complications from cervical spine revision surgery is significantly higher than in first-time procedures. This is due to a number of factors. It is also more difficult to relieve pain and restore function in revision surgery. It is important be aware that the possibility of experiencing long-term neck pain is increased with revision surgery. What are the possible outcomes if treatment is not undertaken?
What are the specific risks of an ACDF? The specific risks of an ACDF include (but are not limited to):
What are the risks of anaesthesia and the general risks
of surgery?
What are the implications of surgery? You will be in hospital for between 1 and 3 days after your surgery. You will be given instructions about any physical restrictions that will apply following surgery, and these are summarised later in this section. Several X-rays of your neck will be taken during surgery to make sure that the correct spinal level is being fused, and also to optimise the positioning of cages, screws and plates (see later). It is critical that you inform us if you are pregnant or think you could possibly be pregnant, as X-rays may be harmful to the unborn child. There is significant variability between patients in terms of the outcome from surgery, as well as the time taken to recover. You will be given instructions about physical restrictions, as well as your return to work and resumption of recreational activities. You should not drive a motor vehicle or operate heavy machinery until instructed to do so by your neurosurgeon. You should not sign or witness legal documents until reviewed by your GP post-operatively, as the anaesthetic can sometimes temporarily muddle your thinking. An important issue relating to spinal fusion is that by fusing level of the spine, slightly increased stress is placed upon the levels directly above and below the fusion. This increases the risk of degeneration at these levels and, therefore, the possibility that you may need further surgery in the future. You should discuss this issue further with your neurosurgeon. Fusion of the cervical spine results in a degree of loss of movement in the neck, mainly in terms of bending your neck forwards and backwards. For a one level fusion, this loss of movement is usually barely noticeable (if at all). There is usually a small but definite loss of movement following a two level fusion, with more significant loss of movement following a three or four level fusion. What do you need to tell the doctor before surgery?
What do I need to do before surgery? If you are fairly overweight, it is advisable that you engage in a sensible weight loss program before you surgery. Please discuss this with your GP and neurosurgeon. In order to prevent unwanted bleeding during or after surgery, it is critical that you stop taking aspirin, and any other antiplatelet (blood-thinning) medications or substances including herbal remedies at least 2 weeks before your surgery. If you normally take warfarin, you will usually be admitted to hospital 3 or 4 days before your surgery. Your warfarin will be ceased at that time (it takes a few days to wear off) and you may be commenced on shorter-acting anti-clotting agents for a few days. These can then be stopped a day or so before surgery. Ideally, you should take a Zinc tablet a day, commencing one month before surgery, and continuing for 3 months after. This should help wound healing. Will I need further investigations? In some patients there is uncertainty either about the diagnosis or exactly which disc or discs in the neck are responsible for their symptoms: in those patients, nerve conduction studies and/or a nerve block may shed light on the diagnostic issues. If you have not had an MRI for over 12 months before your surgery, or if your symptoms have changed significantly since your most recent MRI, then this investigation will need to be repeated to make sure that there are no surprises at the time of surgery! Who will perform surgery? Who else will be involved? How is an ACDF performed? Your skin will be cleaned with antiseptic solution and some local anaesthetic will be injected. The skin incision is about 2-3cm across the front of your neck. It is horizontal and can be made to the left or right hand side of the neck. The thin muscle immediately beneath the skin is split. Dissection is then performed along the natural planes of the neck, going between the food pipe and wind pipe on one side, and the carotis artery (a major blood vessel to the brain) on the other. The thin layer of fibrous tissue (‘fascia’) that covers the front of the spine is dissected away from the disc space. A needle is inserted into the disc space and an x-ray is performed to confirm that the correct disc is being operated upon. The disc is then removed (discectomy) by first cutting the outer annulus fibrosis (fibrous ring around the disc) and removing the nucleus pulposus (the soft inner core of the disc). The dissection is performed using a microscope or special surgical magnifying glasses (‘loupes’) to aid with visualization of the canal and nerves. Disc removal is performed using a combination of special instruments. Adjacent bone is often removed using a fine drill; this is done to recontour the disc space for later fusion, to provide safe access to the spinal canal, and to allow removal of extra bone growth (‘osteophytes’) at the back of the disc space. A ligament (‘posterior longitudinal ligament’) directly in front of the spinal cord is gently removed to allow access to the spinal canal to remove any disc material that may have extruded through the ligament. Each nerve root (when appropriate) is identified and carefully decompressed (this is known as a ‘rhizolysis’). The residual space can be replaced with a cage made out of PEEK, carbon fibre, or trabecular metal. The cage is filled with a combination of bone shavings, growth factors, and/or granules of tricalcium phosphate (a bone graft is rarely taken from the hip). Bone eventually grows through the cage and ideally will join or fuse the vertebrae together (fusion). It usually takes a few months for the vertebrae to completely fuse. In some cases, instrumentation (a plate and screws) will also be used to add stability to the spine. Another X-ray is performed to confirm satisfactory cage, plate and screw positioning, as well as cervical spine alignment. The wound is closed with dissolving sutures. In some cases a wound drain may be used for 24-48 hours post-operatively. What happens immediately after surgery? Most patients are up and moving around within a few hours of surgery. In fact, this is encouraged in order to keep circulation normal and avoid blood clot formation in the legs. You will be able to drink after 4 hours, and should be able to eat a small amount later in the day. It is common to experience swallowing problems after surgery, and this is usually worst on days 2-4 post-operatively. These swallowing problems typically settle over several weeks, but it may take longer. You will have X-rays or a CT scan a day or so after surgery, and can be discharged home when you are comfortable. What happens after discharge? You will need to take it easy for 6 weeks, but should walk for
at least an hour every day. Signs of infection such as swelling, redness or discharge from the incision, and fever should be brought to the surgeon’s attention immediately. A firm neck brace (‘Aspen collar’) is used after surgery. This is worn for 6 weeks if a plate is not placed during surgery (plates are avoided whenever possible due to a risk that they might cause persistent swallowing problems). If a plate is used at surgery, the collar is optional, and can be discarded after a couple of weeks. You cannot drive a motor vehicle while you are wearing the collar, and should also avoid driving for at least 2 weeks after surgery if you are not wearing a collar. You should not drive a motor vehicle or operate heavy machinery your neurosurgeon gives you the go-ahead. You will be reviewed after 6-8 weeks by your neurosurgeon. Until then, you should not lift objects weighing more than 2-3kg, and should not engage in repetitive neck or arm movements. Smoking and anti-inflammatory medications impair fusion. Smoking should be avoided for at least 12 months after surgery, and anti-inflammatory medications can be used for a couple of weeks in the early post-operative period only. You should continue wearing your TED stockings for a couple of
weeks after surgery.
What do I need to tell my surgeon about after the operation?
What are there results of surgery? Generally, the symptom that improves the most reliably after surgery is arm pain. Neck pain and headaches may or may not improve (very occasionally they can be worse). The next symptom to improve is usually weakness. Your strength may not return completely back to normal, however. Improvement in strength generally occurs over weeks and months. Numbness or pins and needles may or may not improve with surgery, due to the fact that the nerve fibres transmitting sensation are thinner and more vulnerable to pressure (they are more easily permanently damaged than the other nerve fibres). Numbness can take up to 12 months to improve. What are the costs of surgery? A quotation for surgery will be issued, however this is an estimate only. The final amount charged may vary with the eventual procedure undertaken, operative findings, technical issues etc. Patients are advised to consult with their Private Health Insurance provider and Medicare to determine the extent of out-of-pocket expenses. Separate accounts will be rendered by the anaesthetist and sometimes the assistant, and hospital bed excess charges may apply. Medical expenses may be tax deductible (you should ask your accountant). You should fully understand the costs involved with surgery before going ahead, and should discuss any queries with your surgeon. What is the consent process? |
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