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Age / Sex : 16 / F
Chief complaint : low back pain, 1 year of ballet training
What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of this case. (Please submit only one answer)
Courtesy: Jina Park, SMG-SNU Boramae medical center
Diagnosis: Unilateral spondylolysis with contralateral pedicular stress reaction
Discussion
Findings:
Plain
radiography and CT:
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defect at
right side pars interarticularis (unilateral spondylolisthesis)
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cortical
thickening and sclerosis at contralateral (left) side pedicle and pars
interarticularis at the same level (contralateral pedicular stress reaction)
MRI:
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bone marrow
edema and sclerosis, left pedicle and pars interarticularis
Diagnosis:
unilateral spondylolysis with contralateral pedicular stress reaction
Discussion:
Unilateral
spondylolysis
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15-30% of
the spondylolysis cases
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clinically
benign : not likely to be associated with forward slippage
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can lead to
contralateral stress related changes (stress reaction or stress fracture),
especially in advanced stages of the pars defect
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the risk of
the pedicular fatigue stresses increase in axial rotation to the contralateral
side of unilateral pars defect, in 12.6-fold as compared to the intact case
Contralateral pedicular stress
related change with unilateral spondylolysis
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CT: method
of choice
ú a thick, sclerotic pedicle with or
without linear defect
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MRI:
detecting early fractures
ú can be used to distinguish between the
reparative stage and the fibrously healed stage of fractures
ú actively healing fractures are
characterized by a decreased marrow SI on T1WI and increased marrow SI on T2WI
References:
1.
Athletes
with unilateral spondylolysis are at risk of stress fracture at the
contralateral pedicle and pars interarticularis: a clinical and biomechanical
study. Sairyo K et al. Am J Sports Med. 2005;33:583-590.
2.
Contralateral
Pedicular Fracture with Unilateral Spondylolysis. Jeong IH et al. J Korean
Neurosurg Soc. 2009;46(6):584-587.
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