Posterior lumbar interbody fusion with stand-alone Trabecular Metal cages for repeatedly recurrent lumbar disc herniation and back pain.

OBJECT: Patients with recurrent sciatica due to repeated reherniation of the intervertebral disc carry a poor prognosis for recovery and create a large burden on society. There is no consensus about the best treatment for this patient group. The goal of this study was to evaluate the 12-month results of the placement of stand-alone Trabecular Metal cages in these patients.

METHODS: The authors performed a retrospective analysis of 26 patients with recurrent disc herniations treated with stand-alone posterior lumbar interbody fusion (PLIF) with Trabecular Metal cages. At 1 year patients were evaluated using the Roland Morris Disability Questionnaire (RMDQ) and a visual analog scale (VAS) for back and leg pain. Furthermore, Likert scores of perceived recovery and satisfaction with the treatment were recorded. Lumbar spine radiographs after 1 year were compared with postoperative radiographs to measure subsidence. Stability of the operated segment was assessed using dynamic radiography.

RESULTS: The patient group consisted of 26 patients (62% male) with a mean age of 45.7 ± 11.4 years (± SD). Patients had a history of 1 (31%), 2 (42%), or more (27%) discectomies at the same level. The mean follow-up period was 15.3 ± 7.3 months. At follow-up the mean VAS score for pain in the affected leg was 36.7 ± 27.9. The mean VAS score for back pain was 42.5 ± 30.2. The mean RMDQ score at follow-up was 9.8 ± 6.2. Twelve (46%) of the 26 patients had a global perceived good recovery. With respect to treatment satisfaction, 18 patients (69%) were content or very content with the operation and would recommend it. Disc height was increased immediately postoperatively, and at the 1-year follow-up it was still significantly higher compared with the preoperative height (mean 41% ± 38.7%, range -25.7 to 126.8, paired t-test, both p < 0.001), although a mean of 7.52% ± 11.6% subsidence occurred (median 2.0% [interquartile range 0.0%-10.9%], p < 0.003). No significant correlation between subsidence and postoperative back pain was found (Spearman's rho -0.2, p = 0.459). Flexion-extension radiographs showed instability in 1 patient.

CONCLUSIONS: Although only 46% of patients reported a good recovery with significant reductions in back and leg pain, 85% of patients reported at least some benefit from the operation, and a marked improvement in working status at follow-up was noted. In view of previously published poor results of instrumented lumbar fusion for patients with failed back surgery syndrome, the present data indicate that Trabecular Metal interbody fusion cages can be used in a stand-alone fashion and should not always need supplemental posterior fixation in patients with recurrent disc herniation without spinal instability, although a long-term follow-up study is warranted.