By: Nick Birch and David Harrison
Spondylolysis – a stress fracture of the pars interarticularis – is a common cause of low back pain in children and adolescents, particularly those who are engaged in athletic pursuits . In the Caucasian population, 4.4 per cent of children have pars fractures by the age of six, rising to 6 per cent by the age of eighteen. The condition is more common in boys than girls and the fractures all occur before skeletal maturity . It is recognised as being significantly more common in athletes .
There is a clear genetic variation across the world with people of African descent having a very low prevalence but almost half of people of Inuit descent will have spondylolysis.
The great majority of fractures occur at L5 (87 per cent) with 10 per cent occurring at L4 and 3 per cent at L3. In 4 per cent of cases there are multiple levels of involvement and in 80 per cent of the fractures are bilateral .
After skeletal maturity, it is rare for spondylolysis to develop except in certain groups of athletes such as cricketers, tennis players, rugby players, weight lifters and track and field competitors.