Abstract
Isthmic spondylolisthesis, i.e. the slipping of one vertebra on another
due to a defect in the pars interarticularis, is a common radiological
finding in the general population and can sometimes be the source of
chronic low back pain. The efficiency of fusion and conservative
treatment in adult isthmic spondylolisthesis has not previously been
documented using valid scientific methods. The primary objective of the
present randomized controlled study was to compare the outcome of
posterolateral fusion in adult isthmic spondylolisthesis with
conservative treatment. Further objectives were to investigate whether
there are specific symptoms and signs associated with spondylolisthesis,
whether pain drawing can predict the outcome of treatment, whether fusion
or conservative treatment changes the mobility of the spine and whether
supplementary transpedicular fixation improves the outcome of fusion.
The studies included 111 patients with isthmic spondylolisthesis. There
were 54 women and 57 men with a mean age of 39 years (range 18-55). The
level of the slip was L5 in 94 patients, L4 in 14 patients and both L4
and L5 in 3 patients. There were 67 patients with a grade I slip, 42 with
a grade II slip and 2 with a grade III slip. The patients were randomly
allocated to (1) posterolateral fusion in situ (40 patients), (2)
posterolateral fusion in situ with transpedicular Cotrel-Dubousset
instrumentation (37 patients) and (3) to a strength training exercise
program (34 patients). Pain, functional disability and range of motion of
the spine were quantified before treatment and at one and two years
follow-up. A pain drawing was completed before treatment. The follow-up
rate was 93%.
This prospective randomized study shows that posterolateral fusion
relieves pain and improves function whereas strength training exercises
have a limited, if any, effect on the symptoms in adult isthmic
spondylolisthesis. The use of supplementary transpedicular
instrumentation improves neither the fusion rate nor the clinical
outcome. The clinical pattern and functional disability in
spondylolisthesis and in low back pain of non-specific origin are
similar. Sciatica in adult isthmic spondylolisthesis is typically not
associated with a positive straight leg raising test. Lower lumbar fusion
does not result in a clinically significant change of sagittal mobility
of the spine. The use of pain drawing improves the selection of patients
for spinal fusion and decreases the risk of exposing patients with a poor
chance of improvement to non-effective surgery.
