Effect of interspinous fixation on adjacent segment degeneration in degenerative lumbar diseases

English Keywords:Lumbar  Interspinous implants  Adjacent segment degeneration

English Abstract:

  【Abstract】 Objectives: To study the effect of interspinous fixation on adjacent segment degeneration in degenerative lumbar diseases. Methods: From September 2007 to September 2009, 76 cases with L4/5 degenerative lumbar diseases were treated with interspinous fixation. The clinical results were assessed by VAS score on lumbar and lower limbs, lumbar JOA score, Prolo functional score and ODI score; the radiological results including segmental lordosis and segment movement ROM of L3/4, L4/5, L5/S1 and L1-S1 were assessed by dynamic lumbar X ray at final follow-up and compared with the pre-operative ones. Adjacent segment degenerations of L3/4 and L5/S1 were assessed by UCLA method. Results: 66 cases were followed up and the average time was 64.6 months. At final follow-up, lumbar VAS, lower limb VAS, lumbar JOA score, Prolo functional score and ODI score were all better than the pre-operative ones(P<0.01). Segmental lordosis angles of L4/5 and whole lumbar spine lordosis were less than the pre-operative ones(P<0.01); L4/5 and whole lumbar spine ROM were less than the pre-operative ones(P<0.01). Segmental lodosis angles of L3/4 and L5/S1 as well as L5/S1 ROM remained no significant change(P>0.05), while L3/4 ROM decreased slightly compared with the pre-operative one(P<0.05). In Wallis group, based on UCLA method, 2 cases changed from grade Ⅰ to grade Ⅱ in L3/4, 4 cases changed from grade Ⅰ to grade Ⅱ and 1 case changed from grade Ⅱ to grade Ⅲ in L5/S1. In Coflex group, 1 cases changed from grade Ⅰ to grade Ⅱ in L3/4, 2 cases changed from grade Ⅰ to grade Ⅱ and 1 case changed from grade Ⅱ to grade Ⅲ in L5/S1. Conclusions: Decompression and interspinous fixation for single segment degenerative lumbar diseases is effective with no symptomatic adjacent segment degeneration, while its effect on the adjacent segment degeneration needs further investigation and long-term follow-up.