- Discussion:
- disruption of the pars interarticularis occurs less frequently at L4;
- symptomatic spondylolysis at this level is reportedly more common in young adults than in children or adolescents;
- in 25% of affected patients, it is associated with either partial or complete sacralization of L5;
- it may be unilateral or bilateral;
- most common in males sustaining trauma;
- intensity of pain in back & of functional impairment are greater w/spondylolysis is at L4 as compared to L5;
- incidence of neurological signs compared to L5 spondylolisis;
- progression to Grade-I Spondylolisthesis has been reported in adults, but severe slipping is unusual;
- neurological signs and symptoms are more frequent, however, when there is progression to Spondylolisthesis