Revision does not mean to do the same thing over. It could mean to undo or to add to something, even extend or make it stronger.

On the left a neurosurgical procedure ‘Selective Dorsal Rhizotomy’ (the old way) affected posterior spinal growth with excessive and progressive lordosis. The long scar is from the original surgery which nowadays is done through a short incision.

Gastrointestinal and spinal discomfort as well as seating difficulties required a substantial correction as stabilization (x-rays).

In this case, substantial hip stiffness required leaving more lordosis than is “normal”. The goal is not “normal” but functional which makes sitting balance and care easier.

Trisomy 21 (extra 21st chromosome, also known as Down Syndrome) is notorious for poor bone formation, especially when bone grafting is carried out. Even the bone that does form is extra flexible. This illustrates a generality that goes beyond this syndrome. Metal fixation holds a position and also helps to increase the success of bone healing. But metal cannot do it alone. If bone does not heal, for any reason, the metal will eventually fail. In this instance we a young woman with Down Syndrome who had a very severe but localized lumbar scoliosis corrected nearly 100% and fused anteriorly with Dwyer’s cable/screw fixation. You couldn’t have asked for better.

Yet, some considerable time later we see the old curve returning with the titanium cable ripped and most of the screws broken [small insets]. She was having balance problems from listing to one side.

The Old cable was removed, the fusion - which actually seemed to be intact but oddly flexible - was revised and a much heavier and more rigid anterior metal device used to replace the failed anterior cable system. It was supplemented by a spanning double rod posterior fixation to help correct the list and further stabilize the critical area of curvature [tall narrow inset]. She did quite well, but look at the longer term [large] x-ray. As her bone is inherently flexible, metal will - and did - eventually fail. However, this time there were no symptoms nor problems. So this is simply a visual curiosity. A ‘lucky break’.

Flat Back
A cause for revision that is not related to failure but to better understanding of postural mechanics, is the flat back syndrome. At the heart of this syndrome is an insufficiency of lordosis. Our bodies ought to be balanced over the center of out feet in relaxed standing posture.

A characteristic lean with the arms held oddly forward gives it away. This individual is not at rest but working to stay balanced as balance derives from having the line of balance pass just behind the hip (stabilizing it) and just forward knee center (stabilizing that as well) to center over the mid foot.

Absence of lordosis makes getting those three relationships lined up. If they don’t line up then one joint or more has to sustain more than relaxed effort to simply stand still. Bending the knees to lean backward is typical. Often it is subtle but eventually quite annoying.

The more severe examples are more quickly seeking intervention and less likely to take ‘no’ for an answer.