Long-term outcomes of long level posterolateral fusion in lumbar degenerative disease: comparison of long level fusion versus short level fusion: a case control study

BACKGROUND: We sought to evaluate the long-term outcomes of long-level instrumented posterolateral fusion (PLF) directly compared to those with short level instrumented PLF for degenerative spinal stenosis. METHODS: From 1987–2002, patients who underwent instrumented PLF with wide decompression for degenerative spinal stenosis were reviewed. A total of 295 patients were available for follow-up over 10 years (mean, 14 years). These patients were divided into Group 1 (fusion of 1 or 2 levels) and Group 2 (fusion of three or more levels). Clinical and radiological outcomes were evaluated. RESULTS: On clinical outcomes, Group 1 showed better results than Group 2 based on the Katz’s Activities Daily Living index (p = 0.024), Kirkaldy-Willis criteria (p = 0.001) and the Korean version of the Oswestry disability index (p = 0.01). However, excellent and good outcome was noted in more than 64.5 % in Group 2. For radiological outcomes, overall fusion rate was higher in Group 1 compared with Group 2, but not significantly different (p = 0.35). However, the metal problems and surgical complications were more developed in Group 2 (p < 0.001). Although the radiologic changes on adjacent segments increased in accordance with the follow-up period, particularly in Group 2 (p < 0.001), no correlation with clinical symptoms was found. CONCLUSIONS: The long-level fusion group maintained acceptable clinical and radiological outcomes compared to the short-level fusion group at minimum of 10 years of follow-up.