Long-term outcome in 132 consecutive patients after posterior internal fixation and fusion for Grade I and II isthmic spondylolisthesis.

Object: The authors assessed the late outcome of patients with Meyerding Grade I and II isthmic spondylolisthesis (IS) who underwent posterior instrumentation and posterolateral fusion (PLF). Decompression and posterior internal fixation with PLF is the classic surgical treatment for painful low-grade IS. Nevertheless, outcome data are scarce and of limited value mainly because they represent small numbers of patients, short follow-up periods, or both.