|
Christopher B. Shields, MD
John R. Dimar, MD
George H. Raque, MD
Y. Ping Zhang, MD
Steven D. Glassman, MD (Louisville, KY)
Optimal timing of decompression
of the spinal cord (SC) following SCI with concomitant spinal
stenosis (SS) remains controversial. Some surgeons recommend
emergent decompression and others believe that timing of decompression
has no effect on long–term outcome.
To answer this question we asked
two critical questions:
1) what constitutes a significant
spinal stenosis following SCI, and
2) what is the optimal timing
of decompression following SCI + concomitant spinal stenosis?
In an earlier experiment, we
performed a T1O laminectomy in Sprague–Dawley rats and inserted
different sized spacers at the level of moderate SCI (25 gm–cm
created using a NYU impactor). Narrowing of the spinal canal
by a 35% sized spacer was the greatest degree of spinal stenosis
that consistently showed neurological improvement (p less than
0.05). In this experiment, 42 Sprague–Dawley rats underwent
a TI 0 laminectomy, a moderate SCI, and insertion of a 35% spacer
which was left in the epidural space for 2, 6, 24, or 72 hours,
then removed. All rats were evaluated weekly for 6 weeks using
the BBB locomotor score. Neurological outcome was significantly
greater the earlier that decompression was performed. BBB scores
for rats in which decompression was performed at 2 hours were
greater than at 6 hours, greater than at 24 hours, and greater
than at 72 hours (p less than 0.05). If extrapolated clinically,
the greater the degree of spinal stenosis existing following
a spinal cord injury, the poorer the neurological outcome. Furthermore,
neurological outcomes improve the earlier the spinal cord can
be decompressed.
|
