Is Chiari/SM always regarded as IS?

[Pooka1]

Apparently not.

From the link Tom posted...

http://www.scoliosisjournal.com/content/3/1/8#B96

Emphasis added

Comment no. 24
Tether, syringomyelia and curve laterality

Cord tethering and Chiari I malformation appear to be major causes of syringomyelia and scoliosis. The laterality of these curves is reported to be about equal, left and right [77]. If cord tethering in syringomyelia does not cause a predominant laterality for the associated scoliosis, how can a short spinal cord explain the laterality patterns of AIS?
Response

In those cases with structural cord tethering and syringomyelia resulting in scoliosis, they are not regarded as idiopathic scoliosis. Also in our group, we have observed the presence of a wider foramen magnum [35] which is contrast to the reported typical cases of Chiari I malformation manifested with juvenile idiopathic scoliosis or syringomyelia in subjects with neurological manifestations. We explain the predominant thoracic AIS curve right laterality by the pre-existent normal axial rotation [57] as stated in the response to Comment no. 23.

I don't know if this is only a small subset of scoliosis plus Chiari/SM but it explains why these cases tend to be excluded from studies of straight AIS. And if they are excluding these cases then they should have separate studies only on them.

[TAMZTOM]

I don't know if this is only a small subset of scoliosis plus Chiari/SM but it explains why these cases tend to be excluded from studies of straight AIS. And if they are excluding these cases then they should have separate studies only on them.

Thought it was an excellent article, Sharon. I'll be reading it again, probably as we travel to Sheffield on Friday. What I thought of general importance was the staggeringly high percentage of AIS kids with descended CTs...25 - 35%? Size and distorted shape of the spinal cord/canal and disproportionate ratios given anterior spinal overgrowth are crucial factors in optimising efforts to adjust posture; which areas to strengthen, which to stretch and (RED FLAG TIME) DO NOT STRETCH. Your stray comment about bed rest should be reined in and studied: I'm not suggesting chain them down, rather, as laying down releases the tether and unloads the curves, how can exercise (upright) do something similar. E.g., although no spine-surgeon, neurosurgeon or orthotist raised the issue, it seemed obvious to me that Tamzin's sacrum is not typically angled; this directly induced more hyperlordosis, which, it turn, can cause hypokyphosis. We've been adjusting the pelvis for 8 months now and recently added even more direct, conscious sacrum postural 'habits' ("tuck your bloody tail in girl!"...she responds to me, "Tuck your belly in, fat boy.")

Wondering how sloppy the medics are in detecting descended CTs with so many possible kids affected. With such a high percentage, it'd be difficult to remove them to a non-idiopathic subset. There are so many possible aetiological factors, treatment/research etc. would become very fragmented. Furthermore, it is not known if the brain hernia causes the scoliosis, or the scoliosis causes the tether. (We'll leave the syrnix formation to another discussion.) I vaguely recall reading about "pre-existing" natural thoracic rotation; even a slight descent (e.g., 2 - 4 mm), could have a devastating effect on curves. These slightly descended CTs are dismissed (I think 5 - 6 mm is the speculative cut-off point). And then we're into vicious cycle territory; slight curve causing slight tether which causes bigger curve and on and on...)