As with any surgical procedure there are potential risks and complications. Fortunately these are infrequent. Those relevant to Direct Lateral Interbody Fusion are as follows;
INJURY TO THE NERVES OF THE LUMBAR PLEXUS
The lumbar plexus is a group of nerves that are originating from the spine which go to the pelvis and leg. The nerve roots originate from the spine and intersect within the psoas muscle. What lets this operation occur safely is an electrical stimulator which gives the surgeon an idea as to where the individual nerves are. This then helps place the guide wire and retractor through the muscle safely to access the disc. It is possible in doing this that any component of the lumbar plexus could be damaged. The risk is highest at the L4 level where the plexus is most complicated. Injury to the nerves could cause pain, numbness or weakness into the leg and the distribution of the damaged branch. It is not uncommon after such surgery from the approach that patients will have some numbness in the front of their thigh and weakness of lifting their hip off the ground. In nine out of ten cases this resolves over four to six weeks.
INJURY TO THE AORTA OR VENA CAVA
The major blood vessels sit on the front of the spine. Direct Lateral Interbody Fusion is a minimally invasive operation which requires good x-ray visualisation of the surgical area to do it safely. If during operation I am unable to get a good view of the surgical levels with x-ray, the procedure may need to be abandoned. The major risks of poor image quality is the instruments or implants could be inadvertently placed anterior to the spine. If this occurs they could cause damage to the major blood vessels (aorta, vena cava) which could potentially result in life threatening haemorrhage. Similarly if an implant or instruments are placed too far toward the back of the spine they could result in damage to the nerves running through the spinal canal.
IMPLANT SUBSIDENCE / MIGRATION OR FAILURE
The recommendation with Direct Lateral Interbody Fusion is that a second surgical procedure be undertaken to place screws in the back of the spine to give added stability. In many cases however, the inter-vertebral implant is sufficiently stable and decision is made not to proceed with supplementary fixation of the back of the spine. It is possible that the implant can push out of the disc space or subside into the vertebral body above or below the disc space. If this occurs, in most cases, it is then a matter of placing some screws in the back of the spine for added support. Rarely it would be the intervertebral implant that needs to be re positioned or removed.
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 have 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.