Simple Lumbar Fusion
LUMBOSACRAL FUSION WITH FACET JOINT SCREW FIXATION
This operation is usually performed at the lowest lumbar disc when there is significant disc degeneration. The disc shows loss of height and there is thickening of the adjacent bone (sclerosis and osteophyte formation). There may be gas in the disc (vacuum phenomenom) which indicates the centre of the disc is no longer liquid. It is important that the next disc up (usually L4/5) is normal or showing very minor changes only. This is usually assessed by MRI scan.
The operation is performed under general anaesthetic, with a tube through the larynx into the lungs. A catheter is placed in the bladder to drain the urine during and after the operation. The patient lies face down on a special frame and head rest.
The back of the spine is exposed by opening the muscles. Firstly, I enter the disc from behind by gently retracting the nerves. All loose and degenerate disc material is removed and then the space is packed with bone to enhance fusion across the disc between the vertebrae. Occasionally, a titanium mesh spacer may be inserted as well.
Secondly, the two facet joints on either side of the spine are cleared of cartilage and packed with bone.
Thirdly, the lateral aspects of the vertebra and sacrum are cleared of soft tissue and more bone placed in the lateral gutters.
This bone graft is taken from the back of the pelvis using the same skin incision. A trapdoor of bone is opened, pieces of marrow bone from within are removed, and then the trapdoor stitched closed. This method minimizes the pain from the bone graft site and gives an ample quantity of bone to be placed in the three locations - in the disc, in the joints and down each side.
Fourthly, two titanium screws 4.5mm in diameter and 30-50mm long are placed obliquely across the two joints to prevent movement while the bone is healing. It is rare for these screws to cause problems or require removal. They will not usually set off metal detectors.
Finally, the wound is washed and closed over a drain with buried stitches which do not require removal. This operation takes between two and two and a half hours. It is usually very sore for the first 24 hours following operation even with a pain pump.
The patient is usually out of bed the next day and goes home on the third or fourth day. The back will be quite sore for the first month - rest and simple pain relief help this.
It takes four to six months to become totally fused but one usually feels significant benefit by two months. An Xray is taken at this stage to assess bone healing. Light work is possible as well as more exercise, e.g., swimming and cycling/exercycling.
Minor complications can occur with any operation but major complications are rare with this procedure.
Fusion may not occur in patients who continue to smoke or who take anti-inflammatories for a prolonged period after the operation although you may receive these for a few days in hospital after your operation e.g., Voltaren or Tilcotil.
Any surgery under general anaesthesia entails risks. These may include pain, nausea and vomiting, drug reactions, problems with the mouth and larynx (voice-box), stomach and intestinal upset including diarrhoea or constipation. Rarely, chest infection, lung collapse, pneumonia, clot, stroke, ulcer or even death. Infection is an occasional risk and damage to nerves can occur (smalll tears of the lining of the nerve can usually be repaired but will require a period of complete bed rest for two or three days). All precautions are taken to minimize these and serious complications occur in less than 1% of cases.
From my own series of over 2400 cases there have been two pneumonias, three leg clots, three lung clots (one fatal), two serious deep infections, several drug related liver reactions, two temporary cauda compressions due to bleeding (resolved), two divided nerves but no permanent paralysis. Death can occur.
Irritation of nerves due to traction or damage to the nerve may leave residual pain or numbness.
In a recent review of 36 cases, 27 (75%) had a good result and 6 were fair (2 are old, one slow, 1 has pain at bone donor site, 1 has knee problems and 1 revised