Below is a 16 year old female with idiopathic scoliosis, who is otherwise healthy.
She noticed gradual development of waist asymmetry and a right rib prominence in the back. She was have daily back pain with athletics and having pain while in school.
The below radiographs/x-rays demonstrate she has a 71 degree right thoracic curve and a left lumbar curve of 45 degrees. On the side radiograph/x-ray she has a normal amount of rounding or kyphosis, at 40 degrees.
In general curves over 50 degrees, in this age group and diagnosis are surgical candidates. When larger curves are present, like the above 71 degree curve, it is recommended to have surgery.
But why?
1. Worsening of the curve. It is generally accepted, based on several long-term studies, that curves over 50 degrees will very slowly progress (get worse) over time, around 0.5 to 1.0 degrees per year. This may not sound very impressive, but if we calculate the future decades of life on top of what curve magnitude is at present, the deformity can become very large.
In the above radiograph/x-ray there is a 71 degree curve, and if there is a 5-10 degree increase every decade then she could have a 86 to 101 degree curve when she gets to her late 30’s. However, it is important to remember that not all patients will have curve worsening, but the average patient will.
Surgery will correct the scoliosis and prevent it from recurring.
2. Pain. As the curve magnitude increases the back pain usually gradually increases in severity, from mild to severe, and can progress from occasional to frequent. In addition, the pain can go from occurring just during strenuous athletic activities to basic activities, like going to school and walking. Studies have reported the average patient with surgically treated scoliosis has some back pain, but less than in patients, with the same size curves, whose scoliosis was not surgically treated.
Surgery helps mitigate pain now and in the future.
3. Body Asymmetry. Smaller curves cause less body asymmetry, larger one cause more body asymmetry. This can be seen in shoulders being uneven, having a rib prominence in the back and the front, waistline being uneven, and body shift.
Surgery 3-dimensionally improves the body position to be as close to normal as possible.
In previous blog posts we have shown growth modulation surgeries of Vertebral Body Stapling and Vertebral Body Tethering (VBT). In a upcoming post the newest technique on the block, ApiFix, will be discussed. However both VBT and ApiFix are not recommended for curves greater than 65 degrees. In addition, there must be adequate growth remaining to get the spine to grow straighter. The case in this post is mostly done growing, so again, neither VBT nor ApiFix are good treatment options.
So for the case in this post, the recommended surgery is a Posterior Spinal Fusion (PSF). There is no maximum curve size for a PSF.
Surgical planning is crucial for optimal results from a PSF. Before surgery flexibility radiographs (below) help plan what to fuse and how to perform the surgery. The below x-rays/radiographs show her biggest curve goes from 75 to 43 degrees, which is a normal amount of flexibility in a 16 year old female.
For this case the decision was to perform T3 to L1 fusion, meaning the top or upper vertebra to fuse is T3 and the bottom or lowest vertebra is L1. The selection of which levels to fuse is only the first step in surgical planning. There are many, many more steps to get the surgery right!
Two things to notice:
1. We did not put two screws at every vertebral level. It is never necessary to put two screws in each vertebra in a fusion. More screws takes more time during surgery, creates more blood loss, increases the risk of a screw being placed incorrectly, and increases the cost of surgery. Meticulous planning of screw placement optimizes surgical correction.
2. In a PSF the bigger curve is always fused. Fusion, or partial fusion, of smaller curves is frequently not needed. Fusions should always be a short as possible, yet be able to achieve the goals of surgery.
The outcome from this surgery demonstrates the typical correction and balance patients have after surgery.