The dura is the sac lining the nerves and contains spinal fluid. This can be torn by instruments resulting in leakage of spinal fluid. Often this is simply repaired with a stitch. Some patients develop a headache for a few days, this would usually resolve. On rare occasions the leakage will continue and lead to a clear fluid discharge from the wound. If this occurs, further surgery to seal the leak may be required. In very rare cases it has been reported that some patients (usually elderly) have developed an unusual type of stroke after having had some leakage of spinal fluid. The mechanism for this is very poorly understood but in its simplest form is said to be due to pressure changes in the brain caused by loss of spinal fluid leading to shearing for some of the smaller blood vessels around the brain. Fortunately as above this is an exceptionally rare complication.
IMPLANT MALPOSITION OR FAILURE
Screws and wedges are placed into the spine, with small margins for error around nerves and other important structures. If the screws are placed too far towards the middle or bottom of the bone it can irritate a nerve running through the spine. If a screw is accidentally placed through the front of the spine the body’s major blood vessels (aorta and vena cava) can be damaged. This could potentially cause life threatening bleeding. It is possible that the screws can loosen in the bone or break requiring replacement. It is also possible the wedges between the vertebral body can sink into the bone with some resulting loss of position which at times can require further surgery.
The aim of fusion is to get bone growing between the vertebral bodies. If bone does not solidly grow between the vertebral bodies this is called pseudarthrosis (false joint). If you are limited in the way of pain this is of no concern. If you have significant pain from the fusion not healing sometimes further surgery can be considered to promote bone healing.
ADJACENT SEGMENT DEGENERATION
A commonly held view is that spinal fusion will lead to early wear and tear on the joints either side and progressive arthritis. In reality this is a much more complicated process and depends upon age related progression of wear and tear changes in the spine, the type of surgery and the overall spinal alignment. If adjacent segment changes do develop over time resulting in stenosis or loss of alignment of the spine, extension of the surgery maybe indicated.
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 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