The American Back Society
Conservative Treatment of Lumbar Spondylolysis in Childhood and Adolescence
K. Saryo, T. Sakai, and N. Yasui
JBJS volume 91-B, #2, February 2009

Spondylolysis is a result of a stress fracture of the pars interarticularis, and because it is a fracture, it can, theoretically unite after conservative treatment if it is identified early before it progresses to pseudarthrosis.  It has been reported that bony union can be obtained by wearing a trunk brace such as a Boston brace or a Damen-type soft corset.  The authors point out that several radiologic features have been identified which can predict healing of the pars defect by conservative management.   They performed a retrospective study and studied the stage of the defect on CT and high signal changes in the adjacent pedicle on T2 weighted MRI.  They proposed a strategy for the conservative management of lumbar spondylolysis in children and adolescence.  The authors noted that bony union of a pars defect can be achieved in children if they wear a trunk brace.  They treated 23 children conservatively for at least three months.  There were 19 boys and four girls with a mean age of 13.5 years in a range of 7 to 17.  They were asked to refrain from assorted activity and to wear a Damen soft thoracolumbosacral type brace.  There were 41 pars defects in 23 patients.  These were classified as an early, progressive or terminal stage on CT.  The early stage lesions had a hairline crack on the pars interarticularis which became a gap in the progressive stage.  A terminal stage defect was equivalent to a pseudarthrosis.  With respect to the T2 weighted MRI images, the presence or absence of high signal change in the adjacent pedicle was assessed and on this basis the defects were divided into high signal change-positive or –negative.  Healing of the defect was assessed by CT. 

In all, 13 (87%) of the 15 early defects healed.  Of 19 progressive defects, only six (32%) healed.  None of the seven terminal defects healed.  Of the 26 high signal change-positive defects 20 (77%) healed after conservative treatment whereas none of the high signal change-negative defects did so.  They concluded that an early stage defect on CT and high signal change in the adjacent pedicle on a T2 weighted MRI scan are useful predictors of bony healing from a pars defect in children after conservative treatment.  They found that a good candidate for conservative treatment should have an early stage defect on CT or a progressive stage defect on CT with a high signal change of the adjacent pedicle on MRI.  They state that for all other types of defects, there is little point in attempting to achieve bony union by conservative means.  The aim of treatment should be to control back pain.  If this is severe, analgesics should be given in addition in addition to wearing of a brace.  We note that this is primarily a problem of the growth plate rather than the disc and particularly in children.  They found that in 80% of children with an immature skeleton and a spondylolysis the slip increases within two years.  This group should be observed carefully until they achieve skeletal maturity.  They noted that isotope scanning can help to diagnose active spondylolysis which may heal without surgery.  They chose not to carry out bone scanning.  CT was needed to assess whether or not the pars defect had healed after treatment and they had no wish to expose their patients to excessive radiation.  Instead, they used an MRI and found that they were able to predict which lesions would heal.  They noted that there is a genetic predisposition to spondylolysis and the incidence of which differs among the various races.