What is the Rate of Lumbar Adjacent Segment Disease after Percutaneous versus Open Fusion?

Objective: Adjacent segment disease (ASD) requiring treatment or re-operation is a common problem after surgery on the lumbar spine. The hypothesis of this retrospective study was that ASD occurs less often following lumbar spine fusion in patients who undergo percutaneous minimally invasive (MIS) instrumentation than in those in whom open instrumentation is used. Methods: A case-control study was performed on consecutive patients who had undergone staged single or two level anterior lumbar interbody fusion for degenerative conditions followed by open or MIS instrumentation from 2002 to 2005 in our institution. ASD was defined as that necessitating additional procedures for new symptoms related to an adjacent lumbar dermatome. Results: One hundred and seventeen patients met the inclusion criteria. Of these, 53 had been followed up by chart or medical record review for longer than one year. There were 23 patients in the MIS group and 30 in the open group. Of the 30 patients in the open group, 9 had developed ASD (30%). Of the 23 patients in the MIS group, 7 had developed ASD (30%). This difference is not statistically significant (P = 1.00). Conclusion: Contrary to our hypothesis, there was no significant difference in incidence of ASD in patients who had underwent open versus percutaneous instrumentation following anterior lumbar interbody fusion.