Spondylolisthesis means forward slipping of a vertebra
on the one below. The term spondylolisthesis is derived from the Greek
words “spondylos” (meaning vertebra) and “olisthesis”
(meaning to slip). This forward slipping of the vertebra occurs when the
posterior (back part) hook mechanism of the vertebra is damaged by one
of the following conditions:
1. Congenital defect of the facet joints or hook mechanism
2. Defect in the pars interarticularis. This is referred to as isthmic
spondylolisthesis. The basic lesion consists of a stress or fatigue fracture
of the pars interarticularis (the portion between the upper and lower
facet joints). The highest prevalence occurs at ages 5 to 7 years and
again during increased activity at ages 11 to 16 years. The lowest incidence
is found in black woman (1, 1 %) and the highest in young sportsmen with
an incidence of up to 50 percent in gymnasts and 36 percent in weightlifters.
It occurs in approximately five percent of the general population. The
L5/S1 level is most commonly involved followed by L4/5.
3. Degeneration of the facet joints with destruction of the cartilage
(degenerative spondylolisthesis). This condition occurs in an older population
group with the highest incidence in the sixties and seventies. In the
late stages of the disease severe narrowing of the spinal canal (spinal
stenosis) and the nerve root canal occurs. The L4/5 level is most commonly
4. Pathological disease where tumour or infection cause elongation or
destruction of the pars interarticularis.
5. Trauma of the spine with fracture of any part of the hook mechanism
except the pars interarticularis.
1. Plainly x-rays remain the most important single modality
to determine anterior displacement, rotation, lumbar lordosis (spinal
curvature) and the sacral angulation. It also provides evidence of the
type of spondylolisthesis in most patients.
2. CT scan (computed tomography) is rarely indicated when plain x-rays
failed to determine the lesion in the pars interarticularis in doubtful
3. Bone scan (Technicium 99) is the most sensitive modality for detecting
early stress fractures in children and young adults.
4. MRI (Magnetic Resonance Imaging) is important for the diagnosis of
neurological compression associated with the spondylolisthesis
1. CONSERVATIVE TREATMENT
Physiotherapy, back exercise programme under the supervision
of a biokineticist, patient education with postural information by an
occupational therapist and weight loss if indicated remain the cornerstones
of conservative treatment and give good results in up to 80 percent of
2. SURGICAL TREATMENT
Surgical treatment is indicated when the conservative
treatment failed to alleviate the pain and the pain intensity is so severe
that the patient cannot live with the pain any longer. It is also indicated
with neurological deficit, especially when progressive and in patients
with a progressive slip.
The traditional surgical treatment consists of decompression
of neurological tissue followed by a fusion without reduction of the slipped
vertebra or instrumentation. Pedicle fixation instrumentation was introduced
later and seems to increase the fusion and success rate. The most recent
surgical treatment consists of decompression of the neurological tissue,
reduction of the spondylolisthesis with restoration of the anatomy, followed
by an anterior and posterior fusion and instrumentation.
An extensive back rehabilitation programme to restore
normal function should always follow the surgical treatment.