Spondylolisthesis (slippage of the spine)
Spondylolisthesis (spondylo = spine, listhesis = slippage) refers to a slippage of one vertebral body over another usually due to defect in the pars interarticularis. This is a common injury of sports that involve repetitive flexion (bending forwards), extension (bending backwards) and rotation of the lower back, such as in cricket fast bowling.
The mechanism involves repeated bending stresses around the thinnest part of the lower vertebrae (pars interarticularis) eventually resulting in a break in the vertebra – Spondylolysis), usually L4-L5 or L5-S1. In more severe cases, the involved vertebra may slip forward, ie. Spondylolisthesis (as per diagram below).
Types and Causes
There are two main theories on what causes the increased stresses on pars interarticularis: 1) Repeated Hyperextension (increased strain from high forces through superior/inferior facets), and 2) Repeated Hyperflexion (erector spinae resists movement as downward pull increasing stress on pars interarticularis).
1. Isthmic/Spondylolysis (50% of cases)
Due to acute or repetitive fatigue leading to stress fracture of the pars interarticularis, more common in males > females.
Common sports include gymnastics, cricket, weight-lifting, football.
Typical x-ray appearance = neck of the ‘Scotty Dog’
2. Degenerative (25%)
Due to degeneration of discs and facet joints; common in 40+ year olds and females > males
Causes long-standing instability, most common at L4-5 level
3. Dysplastic/Congenital (14-21%)
Due to thin vertebral bones or defective facet joints
Most common during growth spurt and females > males
4. Traumatic and Pathological
Less common, due to acute fracture of the spine or bone problems (eg. severe osteoporosis or bone tumours, usu. metastatic)
Classifications and Grades of Severity
The degree of severity (slippage) is graded by how much a vertebral body has slipped forward over the body below it.
GRADE% of vertebral body slipped forwardGrade 1<25%Grade 225-50%Grade 350-75%Grade 475-100% Grade 5Vertebral body completely fallen off
Signs & Symptoms
Often asymptomatic initially
Low back pain +/- buttock and leg pain, especially after exercise (may feel like a muscle strain)
Pain (sciatica) +/- weakness in one or both legs (if severe slippage there could be nerve compression and narrowing of spinal canal – may require MRI)
Aggravating factors are activity, standing, extension, rotation
Easing factor is rest, sitting
X-ray: slipping seen on a lateral view
Palpable slip
Tight hamstrings/ilipsoas often with spasm
Increased lumbar spine lordosis
Waddling gait
Treatment
1. Conservative
Medication (to assist with pain, inflammation and spasm)
Interferential therapy, ice/heat as required for pain relief
Back care advice and education
Activity restrictions (no heavy lifting, excessive bending/twisting/stooping etc that causes stress to lumbar spine)
Physiotherapy rehab program including:
Training for core stability and strengthening exercises for back, abdominals, legs
Stretching for hamstrings, ilipsoas
Postural education and exercises
Joint mobilisations to stiff joints above and below (not at level of slip)
Hydrotherapy, swimming, land-walking exercises
Progressive return to sport when painfree on extension and good spinal stabilisation
2. Surgery
Indications for surgery are:
If conservative management fails leading to prolonged and disabling pain and sciatica
Spinal canal stenosis
Symptomatic radiographic instability
Symptomatic Grade 3-4 slip
Cord compression signs (eg. hyperreflexia, sensory deficits, bowel/bladder dysfunction)
Lower motor neurone lesion
Options for surgery are:
Pars interarticularis repair
Decompression +/- fusion
Interbody fusion
Reduction of the listhetic deformity
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