Deformity Surgery - Complex Scoliosis

There are many types of scoliosis. Childhood scoliosis has a broad range of causes although we now know a lot of them are genetically linked. Idiopathic (cause unknown - but now most likely genetic) scoliosis, neuromuscular scoliosis (associated with developmental or congenital conditions like cerebral palsy for example), or structural childhood scoliosis (due to malformation of the vertebral bodies) are not talked about on this page. This page is concerned with adult degenerative scoliosis, how it presents, how it is treated and the results of reconstructive surgery.

This page assumes you have read the pages on spine anatomy and mechanics and the one on causes of back pain. If not a lot of what follows will not make sense!

One of the most challenging types of deformity to fix is that associated with adult, degenerative scoliosis. Scoliosis is a 3 dimensional deformity (coronal, sagittal and rotational - see page on spine anatomy and mechanics) spanning large segments of the spine. Traditional (open) scoliosis surgery is a massive undertaking with a very significant 'surgical footprint' (see page on minimally invasive spine surgery) left on the patient. Blood loss is usually high, wounds often span mid thoracic segments right down to the sacrum, and risks of infection, nerve damage and medical complications due to the 'surgical footprint' are high. Many patients elect to be treated medically for this condition with very high doses of painkillers or infusion pumps filled with morphine / fentanyl rather than face the trauma of surgery. The pain of scoliosis is subtly different usually from the pain associated with degenerative disc disease. Whereas DDD pain tends to be mostly discogenic in it's character, scoliosis pain is mostly purely mechanical. In other words, as soon as the spine is loaded by standing or sitting, it fails and collapses down (usually in a concertina-type fashion). Muscles quickly fatigue in their attempts to keep the spine erect and this is very painful. If this concertina-ing type of collapse catches nerve roots in it's concertina, then radicular pain ensues. Some patients collapse so much that their rib cage hits the top of their pelvis such that the bottom rib grates with the iliac crest with every breath giving a very protruded look to the abdomen and a typical posture. These patients often can get very good pain relief simply by lying down and unloading their spine but this is no way to spend life. The goal of minimally invasive scoliosis reconstruction is to recreate the stability the patient feels when lying down in all aspects of upright life, without resorting to massive, open surgeries. This can now be accomplished because of the development of the extreme lateral approach to the spine.

On the left is an x-ray showing a severe scoliotic curve. So this is looking at the spine in the coronal plane - i.e. front-on. No medical degree is required to see how this is painful as soon as the patient loads their spine. The red arrow points to the 11th rib, which is pointing straight down into the pelvis. As soon as this patient stands up (this x-ray was taken with the patient lying down) this situation gets much worse. The extreme lateral technique allows each motion segment to be individually reconstructed by sliding a cage across each disc space via a few small incisions on the side of the abdomen. This, of course has to be performed at each level involved in the curve. On the right is the reconstructed x-ray. A green marker indicates at each level a cage placed across the disc space. You can see that the correction is not 100% - to try and achieve this would be impossible - but it is very significantly better than before surgery. Although we try to get as much curve correction as possible you also have to be safe. Too much correction can mean too much stretch on already damaged nerves. The main reason this surgery works very well is not because of the amount of curve correction anyhow - it works because it provides immediate stability to the spine and prevents the concertina-ing collapse.

Without the extreme lateral approach to the spine the only other way to achieve this result over so many levels is to resort to a big open procedure. If you're not too squeamish the photo on the left is the kind of exposure needed to accomplish this correction and result traditionally. To reference how big this dissection is the blades on the metal retractors in the wounds are about 5 cm in width. Because of the lateral approach a much better correction can be achieved through much smaller incisions with on average less than 50mls blood loss per level. To put things in perspective, my hand on the photo to the right is not that big. Two levels have been performed through that small incision and I am just moving up a little to do two more.

Steve Garfin, MD, a very well respected spine surgeon in California reported in the scientific literature his results from using just the extreme lateral approach to correct his large series of patients with scoliosis. Overall the lateral approach using cages as described above resulted in better angle of correction than any other approach, including traditional open approaches. This improvement was by a factor of about 3 when compared with posterior methods. In this same article he demonstrated that at each individual motion segment, the average angle of correction was 4.1 degrees compared with 1.4 degrees for anterior approaches and 1.3 degrees for posterior approaches. This is really just intuitive as well - the deformity is in the lateral plane, so it makes sense that correcting it in the lateral plane gives the best result.

During my training years the most miserable patients I ever saw were these poor souls who lived their upright lives in severe pain because nothing could be done for them. Now I would say that they are my most grateful patients from my entire cohort.

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