Study Design. Acute progression of spondylolysis to spondylolisthesis in an adult without degenerative disc disease at the slip level is reported.
Objective. To document a case of adult-onset progression of isthmic spondylolisthesis, in which the disc space height at the slip level was normal. There were no known risk factors for progression, and the olisthesis occurred acutely after minimal trauma.
Summary of Background Data. Adult progression of spondylolysis to spondylolisthesis is reported infrequently because the highest risk for slip progression is before skeletal maturity. Previous reports documenting progressive slips in adults have uniformly related the olisthesis to progressive disc collapse and subluxation below the pars defect.
Methods. A 39-year-old woman was evaluated for a primary complaint of back and bilateral leg pain. Standing radiographs of her lumbar spine showed an L4–L5 and L5-S1 spondylolysis without spondylolisthesis. She had severe degenerative disc changes at L5–S1. The disc space height was normal at L4–L5. Two years later she was essentially immobilized by back pain after minimal trauma. Standing radiographs demonstrated a new Grade 2 L4–L5 isthmic spondylolisthesis. As demonstrated by magnetic resonance imaging, spontaneous reduction of the olisthesis has occurred with normal disc space height maintained.
Results. An L4–S1 anterior lumbar interbody fusion and posterior decompression and spinal fusion with instrumentation were performed without complication. At this writing, the patient has returned to work and is doing well 1 year after surgery.
Conclusions. This case is important because it illustrates the potential for acute progression of spondylolisthesis with minimal trauma. A patient with known spondylolysis who sustains acute severe exacerbation of his or her back pain should have repeat standing radiographs.