RISKS AND COMPLICATIONS
As with any surgical procedure there are potential complications. Fortunately these are relatively infrequent. Some of the more common ones are described below;
POTENTIAL INJURY TO A MAJOR VEIN
The main veins (vena cava, common iliac veins) are large thin walled blood vessels that can be damaged during this surgery. Bleeding from these veins is impressive but most cases are comparatively easily controlled simply with a finger or pressure. In most cases a vein injury can be simply repaired with some stitches. It is possible that more significant damage to the vein can occur in which case it may be needed to call a vascular surgeon for further help to repair the injury.
DEEP VENOUS THROMBOSIS / PULMONARY EMBOLISM
A retractor is placed in surgery to keep the vein out of the way. In doing this it partially blocks the flow in the vein. Theoretically it is possible to form a clot in the vein and when the retractor is removed this could pass through to the heart/lungs causing pulmonary embolism. This is potentially a life threatening condition. The actual incidence of this occurring in such surgery is very low, certainly lower than that seen in hip and knee replacement surgery.
The arteries are much thicker walled structures and more resilient to injury. It is unlikely that the artery will be torn. The wall of the artery however is made up of lots of rings (like an onion skin). It is possible that either layer can shear during retraction causing a flap. Bleeding can then occur between the layers causing a blockage to the artery which at its worst can mean loss of blood supply to the leg. Should this occur it is an emergency and further surgery will be required to repair the injury. Again the odds of this occurring are quite low.
DISC OR BONE FRAGMENT RETROPULSION
Once we have cleaned the disc space out and placed the implant it is not possible to see the spinal canal. It is possible that a fragment of disc or bone could be pushed back into the space around a nerve. This could cause some persistent sciatica. Should this be persistent after six weeks it may be required to then do an operation from the back of the spine to clean out the space around the nerve.
IMPLANT SUBSIDENCE/MIGRATION AND FAILURE
It is possible that the implant could sink into the bone on either side if it is not strong enough. It is also possible that the fusion doesn’t take and over time this could lead to shifting or subsidence of the implant. Should this occur and be associated with symptoms, at times it may be required to go and put some screws in the back of the spine to provide further support.
RETROGRADE EJACULATION (Men only)
There are some tiny nerves which run down over the front of the L5/S1 disc space which co-ordinate ejaculation. In rare cases these nerves are damaged (around 0.5-1%). These nerves do not control erection or orgasm but simply ejaculation. With orgasm, instead of semen coming out of the end of the penis, it goes up into the bladder. The majority of cases usually recover over a six month period.