Surgical management of isthmic spondylolisthesis.

In order to determine the factors that produce a successful outcome in the surgical management of spondylolisthesis, 44 consecutive patients who underwent surgical treatment were reviewed. Preoperative evaluation was directed towards determining the presence or absence of nerve root compression. The patients without nerve root compression typically underwent fusion alone, while those with evidence of nerve root compression had decompression and fusion. After an average 36-month follow-up, results were good in 78%, fair in 18%, and poor in 4%. There were five complications, all of which were successfully managed. Two patients required reoperation for pseudoarthrosis. An eventual 100% fusion rate was achieved. Results in the patients with Grade III or Grade IV olisthesis were nearly equivalent to the less severe cases. Nine patients received allograft, with a fusion rate equal to the 32 receiving autogenous bone. This study suggests that in patients who have isthmic spondylolisthesis with mechanical lumbar symptoms only, or in patients with low-back pain with radicular extremity pain caused by nerve root irritation, fusion alone is indicated. In patients with documented radiculopathy resulting from nerve root compression, decompression in addition to fusion is indicated.