Posterior lumbar interbody fusion for revision disc surgery: review of 50 cases in which carbon fiber cages were implanted

OBJECT: The authors undertook a study to assess the value of posterior lumbar interbody fusion (PLIF) in which carbon fiber cages (CFCs) were placed in patients undergoing revision disc surgery for symptoms suggesting neural compression with low-back pain. METHODS: The authors followed their first 50 patients for a maximum of 5 years and a minimum of 6 months after implantation of the CFCs. Patients in whom magnetic resonance (MR) imaging demonstrated "simple" recurrent herniation did not undergo PLIF. Surgery was performed in patients with symptoms of neural root compression, tension signs, and back pain with focal disc degeneration and nerve root distortion depicted on MR imaging compatible with clinical signs and symptoms. In 40 patients (80%) pedicle screws were not used. Clinical outcome was assessed using the Prolo Functional Economic Outcome Rating scale. Fusion outcome was assessed using an established classification. Symptoms in 46 patients (92%) improved after surgery, and given their outcomes, 45 (90%) would have undergone the same surgery again. Two thirds of patients experienced good or excellent outcomes (Prolo score > or = 8) at early and late follow up. There was no difference in clinical outcome between those in whom pedicle screws were and were not implanted (p = 0.83, Mann-Whitney U-test). The fusion rate at 2 years postsurgery was 95%. There were minimal complications, and no patients fared worse after surgery. No patient has undergone additional surgical treratment of the fused intervertebral space. CONCLUSIONS: In this difficult group of patients the aim remains to improve symptoms but not cure the disease. A high fusion rate is possible when using the CFCs. Clinical success depends on selecting patients in whom radiological and clinical criteria accord. Pedicle screws are not necessary if facet joints are preserved, and high fusion rates and clinical success are possible without them.