Analysis of preoperative anatomical parameters: Helpful for predicting outcome after decompression for lumbar stenosis?

Aims: Surgical decompression for lumbar spinal stenosis (LSS) causing symptomatic neurogenic claudication has shown to be effective. However, the optimal surgical strategy remains a matter of debate, especially in the presence of concomitant low-grade spondylolisthesis (LGS). We aimed to analyze the influence of preoperative anatomical parameters in patients who underwent selective decompression for LSS in terms of reoperation within 4 years. Methods: This is a single-center cohort study of adult patients with symptomatic LSS who underwent primary decompression without fusion between January 2012 and September 2013 at our institution. Disc height (in mm), facet joint orientation (degrees), and Meyerding grade (0–4) of spondylolisthesis of all index levels (ILs) were analyzed from preoperative magnetic resonance imaging. Patients were contacted 4 years after surgery by follow-up phone call regarding revision surgery of ILs or adjacent levels. For subgroup analysis, ILs not revised (group 1) were compared with ILs that did require revision (group 2). Results: A total of 162 patients (95 men, 67 women, mean age 68.6 years, ± 11.3) were included into the study and a total of 237 ILs in the lumbar spine were analyzed. LGS was present in 25.3% of ILs (60 ILs); there were no ILs with high-grade spondylolisthesis. Twenty-five patients (15.4%) underwent a second lumbar decompression surgery within 4 years involving 34 levels (13.9%). Of these, 24 ILs (10.1%) had recurrent stenosis and 10 (4.2%) had adjacent segment stenosis. Five patients (20%) were revised with decompression and instrumented fusion, and four of these had LGS. ILs with LGS had a significantly higher rate of recurrent stenosis that required revision compared with ILs without spondylolisthesis (18.3% [11/60] versus 7.3% [13/177], p = 0.0148, odds ratio 2.832, 95% confidence interval 1.233–6.899). Disc height and facet joint orientation of ILs showed no statistically significant difference between groups 1 and 2. Conclusions: Concomitant LGS is an important risk factor for recurrent stenosis after decompression of LSS without fusion. This must be taken into account for preoperative surgical planning and patient counseling