Spondolysis/-listhesis
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Medical Spondylolysis
-isthmic spondylolysis represents a fatigue fx of the1 pars interarticularis
of the neural arch
-high incidence of radiographic spondylolysis in gen population, but vast
majority occur w/out associated symptoms
-symptomatic pars lesions a problem in adolescents, esp athletes
-tx requires initially rest and rehab w/consideration of bracing or surgery

Definition
-defect in the par interarticularis of the vertebral arch

Spondylolysis and Spondylolisthesis
-Wiltse et al. Clin Orthop 117;1976

Type I
-dysplastic (congenital abnls of L5 or the upper sacrum allow ant displacement
of L5 on the sacrum)

Type II
-isthmic (lesion in the pars interarticularis)
-subclassified:
-lytic (fatigue fx of pars)
-elongated but intact pars
-acute fx

Type III
-degenerative (secondary to long standing intersegmental instability
w/associated remodelling of the articular processes)

Type IV
-traumatic (acute fxs in vertebral arch other than the pars)

Type V
-pathological (gen or focal bone dz affecting vertebral arch)

Isthmic (type II) spondylolysis
-3 to 6% of population
-Roche and Rowe studied 4200 cadaveric spines and found incidence of 4.2%
-6.4% for white males, 2.8% for AA males, 2.3% for white females, and 1.1% for
AA females
-No sig inc in rate w/inc from 20-80 yrs of age
-males 2-3 times more affected
-Majority of spondylitic defects occur at L5 (85-95%)
-L4 is the next most common level (5-15%)
-Association of pars defect and spina bifida occulta
-spondylolysis is associated w/spondylolisthesis 25% of the time
-Fredrickson found an incidence of spondylolysis of 4.4% at age six, 5.2% at
age 12 , and 6% by adulthood
-family members have a higher rate of spondylolysis
-higher incidence in young athletic population
-Rossi et al. note a 15% incidence in adolescent athletes (lifters, wrestlers,
gymnasts)

Progressive Spondylolisthesis
-risk is small w/low grade spondylolisthesis
-3% slip progression of greater than 20% over 3.8 yrs (Danielson)
-10-12% slip progression of greater than 10%

Diagnosis
-plain x-rays
-defect is defined as a lucency in the region of the pars
-collar or broken neck of scotty dog seen in lateral oblique x-rays (45
degrees)
-defect needs to be tangentially aligned to the x-ray beam
-20% of pars defects are seen on x-rays
-SPECT and CT are more sensitive for ID of pars defect

Tx
-most pts w/symptomatic spondylolysis do well w/conservative care
-many pars lesions may heal w/conservative care, particularly early stage
unilateral defects
-osseous healing is not necessary to achieve an excellent clinical outcome
w/full return to activities
-no published controlled trials on tx for spondylolysis
-bone healing has been shown to occur w/rigid, soft, or no bracing
-rigid bracing is not mandatory
-rest and avoidance of activities associated w/inc pain
-minimize the biomechanical forces responsible for propagation of stress rxn