The purpose of this study is to report the results of nonoperative treatment of presumed traumatic spondylolysis in a young patient population seen at the Walter Reed Army Medical Center Orthopaedic Surgery Spine Service from 1986 to 1994. A retrospective chart review analysis with recent follow-up was performed on 29 patients diagnosed through clinical examination and plain radiographs. Bone scan was reserved for those patients with an examination consistent with spondylolysis yet inconclusive plain films. All patients were treated with activity modification (to include a temporary profile for active duty military), full-time bracing (most commonly a thoracolumbosacral orthosis), and nonsteroidal anti-inflammatory drugs. Narcotic analgesics were added to this regimen, if indicated. There were 23 males and 6 females with an average age of 21 (range 13-31). There were 7 United States Military Academy cadets, 7 dependent children, 5 noncommissioned officers, 6 enlisted, and 4 officers. Of the 29 patients with spondylolysis, 20 had an L5 defect, 6 had an L4 defect, 4 had an L3 defect, and 1 had an L2 defect. Two of the 29 patients healed their spondylolysis, but the remainder failed nonoperative treatment. In the population of patients referred to our institution, spondylolysis is not a benign process. The literature suggests that the majority of these injuries heal, yet this has not been our experience. We propose that if the patient is diagnosed acutely with a fracture of the pars interarticularis and the aforementioned proven regimen is initiated, the chances for a successful nonoperative outcome are optimized.(ABSTRACT TRUNCATED AT 250 WORDS)