The prevalence of degenerative spondylolisthesis (DS) increases with age. With an ageing population there will be increasing demands for adult deformity surgery, with associated significant financial and complication costs. The prevalence of lytic spondylolisthesis (LS) is 6–8%. Our clinical observation is that it is extremely rare to see LS in the presence of DS and therefore the objective was to formally describe the prevalence of LS in combination with DS to assess the hypothesis that 6–8% of patients with DS should also have LS. If this is not the case it may further our understanding of the pathogenesis of DS, which could aid in future prevention or treatment.

A retrospective review of erect lateral lumbar radiographs demonstrating lumbar spondylolisthesis was performed. Radiographs were identified and analysed on the hospital Synapse Picture Archiving and Communication System (PACS). Search criteria were radiographs requested by primary care and patients aged over 60.

101 patients with spondylolisthesis were identified. 89% were requested for back or leg pain. There were 89 patients with DS (69.7% women) and 12 with LS (83% men). The average age of DS and LS patient was 75 and 70 respectively (not significant). There were no cases found with both DS and LS. This was significantly different to the expected amount of 6% (p=0.03). The level of DS was at L3/4 in 11.2% (n=10), L4/5 in 79.8% (n=71) and L5/S1 in 16.9% (n=15). 2 levels were involved in 7 patients. 94.4% (n=84) demonstrated a Meyerding grade 1 slip and 5.6% (n=5) grade 2 slip. For LS the slipped level was at L5/S1 in all cases. 66.7% (n=8) had a grade 1 slip and 33.3% (n=4) a grade 2 slip.

We found no cases of lytic spondylolisthesis in the presence of degenerative spondylolisthesis. We hypothesis that the presence of spondylolysis or lytic spondylolisthesis may be protective against development of degenerative spondylolisthesis. More work is needed to explore this further.