Spondylolisthesis
Definition: the
slipping forward of one vertebra upon another.
Incidence is approximately 6% of population. Common in gymnasts,
football players, weightlifters.
Spondylolysis is the
presence of a bony defect at the pars interarticularis, the space between the
superior and inferior facet, and can lead to spondylolysthesis
Etiology
(Wiltse classification):
o
Type I = dysplastic deficiency of superior sacral facet,
inferior 5th lumbar facet, or both
o
Type II = isthmic type, defect in pars interarticularis
(types I & II most common)
o
Type III = degenerative form, mostly L4-5
o
Type IV = traumatic form
o
Type V = pathologic form, caused by neoplasm
Signs/Symptoms:
o
May be asymptomatic
o
Back pain
o
Leg pain
o
Radicular pain, bowel or bladder symptoms rare
o
Isthmic spondylolisthesis commonly presents between 10-15
years
o
Extent of slippage may not correlate with pain
o
L5 slippage on sacrum is most common
Radiographs:
o
Lateral view shows defect
o
Oblique view demonstrates “Scottie dog” with “collar” or
“broken neck” sign indicating pars defect
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Axial CT
image of a 17-year-old demonstrating unilateral spondylolysis with sclerosis
of the contralateral pars. |
Classification:
o
Slip angle = measure of lumbosacral kyphosis, helps
determine likelihood and presence of progression on younger patients
o
Meyerding’s classification
o
Grade I = 1-25% slippage
o
Grade II = 26-50% slippage
o
Grade III = 51-75% slippage
o Grade IV = 76-100% slippage
Treatment:
- Grades
I and II managed conservatively by restricting aggravating activities, bracing
to reduce lumbar lordosis, physical therapy
- Grade III
& IV slips are at risk for progression, especially in skeletally immature
patients, and fusion is recommended
- Fusion
indications are: demonstrate progression of slip, greater than 50% slip,
fail to respond to conservative measure, and skeletal immaturity
- Combined spinal decompression and fusion are indicated if neurological findings present (numbness, weakness, bowel or bladder compromise
- Pars repair possible in young patients with minimal slip
