Anterior Cervical Discectomy And Fusion

Anterior cervical discectomy and fusion is an operation designed to remove a fragment of disc or other tissue causing compression of nerves of the spinal cord in the neck. The pressure on the spinal cord can cause pain, numbness, weakness in the arms and or legs, loss of fine motor function and unsteadiness on the feet. Pressure on the nerves in the neck can cause either pain, numbness or weakness in the distribution of a particular nerve running down the arm. Pressure on the nerves and spinal cord in themselves are unlikely to be the source of pain in the neck which is more likely to be due to the underlying degeneration. Whilst surgery is good to relieve pressure on the spinal cord, nerves and subsequent symptoms into the limbs, it is not good for relieving pain in the neck.

THE PROCEDURE

The operation is performed under an anaesthetic. Once you are asleep a catheter is passed into the bladder and electrodes placed onto muscle groups to monitor nerve function during the surgery. A cut is made usually on the left hand side of the neck. The space between the main artery and vein going to the brain, wind pipe and gullet is opened. This allows access to the front of the spine. A marker is placed over the neck and an x-ray taken to ensure the correct level is selected. The muscles are then elevated from the front of the neck bones and a retractor placed. The disc is then cut with a scalpel and then removed. The back margin of the disc can then be removed to gain access to the space around the spinal cord and nerves. Any material in this space can then be removed. A burr can be used to remove the back portion of the vertebra to relieve any other areas of compression around the spinal canal.

Once this is done, a plastic implant is inserted into the disc space. Different size trials help select the correct sized implant. Bone substitute is injected into the actual implant before it is inserted into the disc space. This is held in place with a small plate with screws going into the bone. In some cases rather than using an implant in the disc space, a cut is made over the pelvis and a piece of bone cut into the right shape and used to fill this space between the vertebra. A drain is inserted and the wound closed.

You are then placed on a bed before the anaesthetic is reversed. When you wake up you will have a drip on your arm, hooked to a pump which you will control to give yourself pain relief. You may have a catheter in the bladder. There will be a surgical drain coming out from next to the incision. The catheter and drain will be removed on the first morning following surgery and you will be mobilised with the physiotherapist and nursing staff. Approximately fifty percent of patients will be comfortable enough to go home the first day following surgery with the remainder usually going home on the second day.

WHAT YOU CAN EXPECT AFTER YOUR SURGERY

At home you are able to be active as you can. The physiotherapist would have demonstrated some simple movement exercises for the neck and I encourage you to walk for exercise. The stitches are beneath your skin and hence do not need to be taken out. The dressing on the wound should be left in place for three or four days. It can then be removed. You can get your wound wet, just make sure you dry it. We usually organise for you to have a review appointment around six weeks after your surgery with an x-ray. You are able to drive when your pain has settled enough such that you have a reasonable range of movement in your neck and you are happy you can safely control a car. You are able to return to work when you feel comfortable enough to do so.

Following surgery, a number of patients will have some discomfort or awkward feeling swallowing for some time. This is consequent to the surgical approach. It usually settles over time.

POTENTIAL RISKS/COMPLICATIONS

As with any surgical procedure there are potential risks and complications which fortunately are infrequent. The risks and complications relevant to Anterior Cervical Discectomy and Fusion are;

INFECTION

From this sort of surgery it is exceedingly rare. Should you develop infection, treatment would range from requiring simple antibiotics through to needing further surgery to clean the infection out.

COMPLICATIONS RELATING TO SURGICAL ACCESS

As above, the approach to access the spine runs between the artery and vein going to and coming from the brain (carotid neurovascular bundle) as well as your wind pipe (trachea) and gullet (esophagus). This space is usually easy to access. Rarely, any of these structures could be damaged in the approach. This could cause stroke, breathing difficulties or infection. There is a nerve that runs down with the artery and vein and comes back up with the trachea and esophagus which goes to the voice box. Some times this nerve can be stretched leaving you with some hoarseness of voice which usually recovers. Rarely is the nerve permanently damaged leading to permanent hoarseness of the voice. Coincidentally it is this nerve that Neville Wran had damaged during an operation on his neck.

SPINAL CORD / NERVE INJURY

The purpose of the surgery is to remove pressure on the spinal cord or nerves and obviously involves working around these structures. It is possible that they can be damaged during the surgery. The worst case scenario is this could lead to quadriplegia or possible nerve damage which could result in pain, weakness or numbness in the distribution of the injured nerve. Such complications are very unusual from this type of surgery. It is possible that post operatively there could be significant bleeding around the spinal cord or nerve (epidural hematoma). Should progressive nerve defect develop after surgery this may require emergency surgical drainage.

INSTRUMENTATION MALPOSITION / FAILURE

It is possible that the implants can be incorrectly placed and this can cause damage to the spinal cord or nerves. Again this is highly unusual. On occasions the implant can sink into the bone if it is not strong enough. This may require further surgery.

PSEUDARTHROSIS

The operation is designed to fuse two adjacent vertebra. The fusion rate for a single level operation should be in the region of 95 or 96%. If the vertebra do not fuse together and you have limited in the way of symptoms, this is of no consequence. Occasionally failure to fuse (pseudarthrosis) is associated with significant pain in which case further surgery can be undertaken. This usually involves placement of some screws across the same levels at the back of the spine. Occasionally it may involve re-doing the surgery from the front of the neck.

MEDICAL COMPLICATIONS

There are a variety of medical complications which can occur with major surgical procedures. The likelihood that these will occur to some extent is determined by your health before surgery and past medical history. Fortunately with modern anaesthesia and perioperative care, medical risks involved in elective surgery are comparatively low. Common surgical complications such as deep venous thrombosis, pulmonary embolism, pneumonia, urinary tract infection and skin pressure areas that are best avoided with early mobilisation.

If you have any further questions regarding your procedure, please don’t hesitate to ask.

Rob Kuru, Spinal Surgeon