A New Method to Treat Severe Asymptomatic Pre-existing Degeneration of Adjacent Segment: a Retrospective Case-control Study
Abstract Background Pre-existing degeneration of adjacent segment is an important risk factor for adjacent segment degeneration (ASD), but limited and controversial studies have addressed its management. Methods Patients with symptomatic degeneration of the L5/S1 segment warranting surgical interference and severe asymptomatic degeneration of the L4/5 segment were retrospectively analyzed. Among them, those who underwent interbody fusion in the causative (L5/S1) segment and distraction of the intervertebral space and facet fusion in the adjacent L4/5 segment were included as Group A (n=103). Patients who underwent interbody fusion in both L5/S1 and L4/5 segments were included as Group B (n=81). Clinical and radiographic outcomes were evaluated. Results Mean follow-up was 58.5 months (range, 48-75 m). No significant difference in clinical outcomes or the incidence of adjacent segment degeneration in L3/4 segment was found between Groups A and B. Compared with Group B, less bleeding (315±84 vs. 532±105 ml), shorter operation time (107±34 vs. 158±55 min) and lower costs (13,830±2640 vs. 16,020±3380 US$) were found in Group A (P<0.05). In Group A, disc height ratio (DHR) of L4/5 segment was significantly increased from preoperative value of 0.40±0.13 to last follow-up value of 0.53±0.18 (P<0.05), while the degree of canal stenosis (DCS) was decreased from preoperative value of 34.3±11.2% to last follow-up value of 15.9±9.3% (P<0.05). Conclusions This new method could be effective in treating severe asymptomatic pre-existing degeneration of adjacent segment in lumbar spine.