Lumbar spondylolysis is a relatively common condition that causes severe and perennial back pain in young populations. Conservative treatment of this condition may be futile, and may eventually require surgical treatment such as direct repair of pars defect and a segmental lumbar fusion with an anterior or posterior approach. Recently, of surgical treatment methods for spondylolysis, direct repair surgery of pars defect has been focused due to its inherited strengths. Most importantly, fusion surgery caused the affected segment to lose the nature range of motion and furthermore adjacent segment to be adversely affecting such as adjacent disc disease or degeneration, while direct repair theoretically could preserve the motion of the affected segment, which do not cause the adjacent segment problems as being the fusion surgery, as well as could produce better surgical outcomes with relatively less invasive technique as compared to fusion surgery. Moreover, previous articles have demonstrated that the direct repair surgery for spondylolysis of lumbar spine could achieve great functional and radiological outcomes. However, most of the previous studies was conducted using lower level designed study such as retrospective and small sample size, thereby prior literature does not provide clear information on the therapeutic outcome of direct repair for lumbar spondylolysis, especially for managing spondylolysis of young population.

Therefore, The investigators aimed to evaluate and determine the outcomes of direct repair surgery for lumbar spondylolysis in young population. To our knowledge, this is the first report that describes the functional and radiological outcomes of direct repair for spondylolysis in young populations with prospective cohort study design and relatively large sample size.

Inclusion Criteria:

• patients for whom conservative treatment for six months and three-times injection treatments had failed
• a follow-up period of one year or more after surgery

Exclusion Criteria:

• patients with abnormal muscle activity or ambulation such as parkinsonism and neuromuscular disease.
• patient inability to accurately record results of preoperative and postoperative questionnaires due to problems such as a history of stroke, dementia, or major medical illness that required intensive treatment
• patient follow-up was limited to one year or less