I agree that the straight dope is likely not known. In the mean time, here's what I found for long term on fusion... emphasis added. N.B. these might be false.
-----------
Here's a 20-30 years follow up
http://www.ejbjs.org/cgi/reprint/62/3/364.pdf
---------------
Here's a review of long term H-rod studies
http://www.coa-aco.org/coa-bulletin/...deformity.html
---------------
Here's some long-term L fusion data from relatively early in the surgical period I think that may be one of the studies to establish the relationship between fusing past L3 and later problems...
http://journals.lww.com/spinejournal..._Fusion.4.aspx
------------
Long term on untreated scoliosis...
http://www.ejbjs.org/cgi/reprint/63/5/702
-----------
Here's a 20-30 years follow up
http://www.ejbjs.org/cgi/reprint/62/3/364.pdf
ABSTRACT: One hundred and ten scoliotic patients
underwent correction and spine fusion by one of us
(J. H. M.) at Gillette Children's Hospital between
1947 and 1957. Sixty-one of these patients were evaluated
in 1977 for this follow-up study. The evaluation
consisted of physical and roentgenographic examination,
photographs, and a detailed psychosocial
analysis. The aims of the study were to evaluate: (1) the
long-term stability of the fusion; (2) the incidence and
severity of low-back pain; and (3) the degree of integration
of the patient into society.
The results showed that a solid fusion had no significant
loss of correction with time. Eighty-four per
cent of the patients lost only zero to 5 degrees of correction
during an average follow-up of twenty-six
years. Low-back pain was found to be no more frequent
than in the normal population in this age group,
and there was less low-back pain than in a comparable
series of scoliotic patients without fusion.
There was no correlation between the occurrence
of low-back pain and the length or magnitude of the
fused curve or the lowest extent of the fusion. An unexpected
finding was the high incidence of neck pain, the
cause of which is unknown. Psychosocial analysis revealed
that the patients were productive, active, stable
persons who were working and contributing members
of society.
underwent correction and spine fusion by one of us
(J. H. M.) at Gillette Children's Hospital between
1947 and 1957. Sixty-one of these patients were evaluated
in 1977 for this follow-up study. The evaluation
consisted of physical and roentgenographic examination,
photographs, and a detailed psychosocial
analysis. The aims of the study were to evaluate: (1) the
long-term stability of the fusion; (2) the incidence and
severity of low-back pain; and (3) the degree of integration
of the patient into society.
The results showed that a solid fusion had no significant
loss of correction with time. Eighty-four per
cent of the patients lost only zero to 5 degrees of correction
during an average follow-up of twenty-six
years. Low-back pain was found to be no more frequent
than in the normal population in this age group,
and there was less low-back pain than in a comparable
series of scoliotic patients without fusion.
There was no correlation between the occurrence
of low-back pain and the length or magnitude of the
fused curve or the lowest extent of the fusion. An unexpected
finding was the high incidence of neck pain, the
cause of which is unknown. Psychosocial analysis revealed
that the patients were productive, active, stable
persons who were working and contributing members
of society.
Here's a review of long term H-rod studies
http://www.coa-aco.org/coa-bulletin/...deformity.html
---------------
Here's some long-term L fusion data from relatively early in the surgical period I think that may be one of the studies to establish the relationship between fusing past L3 and later problems...
http://journals.lww.com/spinejournal..._Fusion.4.aspx
Although patients after lower lumbar fusion report more pain than the general population and have more radiographic evidence of instability and stenosis than expected for the general population, they are generally doing well and are satisfied with the results of their surgery.
Long term on untreated scoliosis...
http://www.ejbjs.org/cgi/reprint/63/5/702
ABSTRACT: Two hundred and nineteen patients
with untreated adolescent idiopathic scoliosis who were
seen at the University of Iowa between 1932 and 1948
were studied, and recent information was available on
194 of the patients. The mortality rate was 15 per cent.
Backache was somewhat more common in these patients
than in the general population, although it was
never disabling. The backache was unrelated to the
presence of osteoarthritic changes on roentgenograms.
Many curves continued to progress slightly in adult
life, particularly thoracic curves that had reached between
50 and 80 degrees at skeletal maturity. The lumbar
components of combined curves between 50 and 74
degrees also tended to progress. Pulmonary function
was affected only in patients with thoracic curves.
with untreated adolescent idiopathic scoliosis who were
seen at the University of Iowa between 1932 and 1948
were studied, and recent information was available on
194 of the patients. The mortality rate was 15 per cent.
Backache was somewhat more common in these patients
than in the general population, although it was
never disabling. The backache was unrelated to the
presence of osteoarthritic changes on roentgenograms.
Many curves continued to progress slightly in adult
life, particularly thoracic curves that had reached between
50 and 80 degrees at skeletal maturity. The lumbar
components of combined curves between 50 and 74
degrees also tended to progress. Pulmonary function
was affected only in patients with thoracic curves.
Comment