Clinical and radiological data were reviewed for all patients
with mucopolysaccharidoses (MPS) with thoracolumbar kyphosis managed
non-operatively or operatively in our institution. In all 16 patients were included (eight female: eight male; 50%
male), of whom nine had Hurler, five Morquio and two Hunter syndrome.
Six patients were treated non-operatively (mean age at presentation
of 6.3 years; 0.4 to 12.9); mean kyphotic progression +1.5o/year;
mean follow-up of 3.1 years (1 to 5.1) and ten patients operatively (mean
age at presentation of 4.7 years; 0.9 to 14.4); mean kyphotic progression
10.8o/year; mean follow-up of 8.2 years; 4.8 to 11.8)
by circumferential arthrodesis with posterior instrumentation in
patients with flexible deformities (n = 6).Aims
Methods
The belief that an intervertebral disc must degenerate
before it can herniate has clinical and medicolegal significance,
but lacks scientific validity. We hypothesised that tissue changes
in herniated discs differ from those in discs that degenerate without
herniation. Tissues were obtained at surgery from 21 herniated discs
and 11 non-herniated discs of similar degeneration as assessed by
the Pfirrmann grade. Thin sections were graded histologically, and
certain features were quantified using immunofluorescence combined
with confocal microscopy and image analysis. Herniated and degenerated
tissues were compared separately for each tissue type: nucleus, inner
annulus and outer annulus. Herniated tissues showed significantly greater proteoglycan loss
(outer annulus), neovascularisation (annulus), innervation (annulus),
cellularity/inflammation (annulus) and expression of matrix-degrading
enzymes (inner annulus) than degenerated discs. No significant differences
were seen in the nucleus tissue from herniated and degenerated discs.
Degenerative changes start in the nucleus, so it seems unlikely
that advanced degeneration caused herniation in 21 of these 32 discs.
On the contrary, specific changes in the annulus can be interpreted
as the consequences of herniation, when disruption allows local
swelling, proteoglycan loss, and the ingrowth of blood vessels,
nerves and inflammatory cells. In conclusion, it should not be assumed that degenerative changes
always precede disc herniation. Cite this article:
