Spondylolysis and spondylolisthesis. Treatment by internal fixation and bone-grafting of the defect.

Eighteen patients who had symptomatic spondylolysis or Grade-I spondylolisthesis, and whose symptoms had not been relieved by non-operative treatment, were operated on using the Buck method for bone-grafting and internal fixation of the defect of the pars interarticularis with screws. There were six male and twelve female patients and the average age was twenty years (range, fourteen to thirty-eight years). The amount of slipping ranged from zero to ten millimeters. After an average period of follow-up of forty-one months (range, twenty-four to seventy-two months), the result was excellent in ten, good in five, and poor in three patients. Thus, a satisfactory result was obtained in 83 per cent of the patients.