Incidence and Prevalence of Surgery at Segments Adjacent to a Previous Posterior Lumbar Arthrodesis.
Podium presentation at EuroSpine 2010
Vienna, September 17th 2010
Awarded 2010 EuroSpine Best Podium Presentation
Vienna, September 17th 2010
Awarded 2010 EuroSpine Best Podium Presentation
Abstract
Adjacent segment disease (ASD) following lumbar spinal fusion has been an important reason behind the development of non-fusion stabilisation technology. However, the prevalence & incidence of this condition remain unclear. The prevalence rates reported in the literature vary and rarely has the annual incidence been analysed, in the lumbar spine. Conflicting reports exist regarding risk factors - especially the length of the fusion - perhaps due to the heterogeneous nature and relatively small size of study cohorts.
The aim of the current study was to determine the annual incidence and prevalence of ASD, requiring further lumbar surgery, in a large retrospective cohort study, and to explore possible risk factors.
A postal and telephone survey was undertaken of 912 patients who underwent 1000 consecutive posterior lumbar interbody fusion (PLIF) procedures between October 1993 and October 2009, with mean follow-up (F/U) of 62 months (range: 5 mnths – 16 yrs), to ascertain whether they had undergone further surgery since the index procedure. End points of further surgery for ASD, surgery free survival or death were recorded. F/U rate was 91%, including the 11% of patients who had died. The annual incidence and prevalence of ASD requiring further surgery was determined for all patients and sub-groups with Kaplan-Meier survivorship analysis. Logistic regression analysis was used for examination of possible risk factors. Significance was set at p<0.05. Results are expressed as means with 95% confidence intervals.
Further surgery for ASD occurred following 125/1000 or 12.5% of procedures at a mean 44 months (range: 2.3 – 162 months). Based on Kaplan-Meier survivorship analysis, the annual incidence of further surgery for ASD for all patients was 2.6%(95%CI: 2.2-3.0) with prevalences of 13% & 23% at 5 & 10-years, respectively. The annual incidence varied significantly with the number of levels fused (p<0.0001): 1.8%(1.4-2.2) following fusion at 1-level, 3.4%(2.3-4.5) post 2-level and 5.4%(3.9-7.0) post 3 & 4-level. The 5 & 10-year prevalences were 9% & 16%, 16% & 33% and 30% & 40% for 1, 2 and 3 & 4-levels, respectively. The annual incidence of surgery for ASD following single level fusion for lytic spondylolisthesis was significantly lower than that following fusion for degenerative spondylolisthesis (p=0.037): 1.0%(0.4-1.6) vs. 2.2%(0.7-3.6), respectively.
In conclusion, approximately 1 in 4 patients may require further surgery for ASD within 10 years of undergoing posterior lumbar arthrodesis (PLIF) for degenerative disease. The prevalence varies however with the number of levels fused and the condition treated. It is lowest (10%) following 1-level fusion for lytic spondylolisthesis and highest (40%) following 3 or 4-level fusion.
Adjacent segment disease (ASD) following lumbar spinal fusion has been an important reason behind the development of non-fusion stabilisation technology. However, the prevalence & incidence of this condition remain unclear. The prevalence rates reported in the literature vary and rarely has the annual incidence been analysed, in the lumbar spine. Conflicting reports exist regarding risk factors - especially the length of the fusion - perhaps due to the heterogeneous nature and relatively small size of study cohorts.
The aim of the current study was to determine the annual incidence and prevalence of ASD, requiring further lumbar surgery, in a large retrospective cohort study, and to explore possible risk factors.
A postal and telephone survey was undertaken of 912 patients who underwent 1000 consecutive posterior lumbar interbody fusion (PLIF) procedures between October 1993 and October 2009, with mean follow-up (F/U) of 62 months (range: 5 mnths – 16 yrs), to ascertain whether they had undergone further surgery since the index procedure. End points of further surgery for ASD, surgery free survival or death were recorded. F/U rate was 91%, including the 11% of patients who had died. The annual incidence and prevalence of ASD requiring further surgery was determined for all patients and sub-groups with Kaplan-Meier survivorship analysis. Logistic regression analysis was used for examination of possible risk factors. Significance was set at p<0.05. Results are expressed as means with 95% confidence intervals.
Further surgery for ASD occurred following 125/1000 or 12.5% of procedures at a mean 44 months (range: 2.3 – 162 months). Based on Kaplan-Meier survivorship analysis, the annual incidence of further surgery for ASD for all patients was 2.6%(95%CI: 2.2-3.0) with prevalences of 13% & 23% at 5 & 10-years, respectively. The annual incidence varied significantly with the number of levels fused (p<0.0001): 1.8%(1.4-2.2) following fusion at 1-level, 3.4%(2.3-4.5) post 2-level and 5.4%(3.9-7.0) post 3 & 4-level. The 5 & 10-year prevalences were 9% & 16%, 16% & 33% and 30% & 40% for 1, 2 and 3 & 4-levels, respectively. The annual incidence of surgery for ASD following single level fusion for lytic spondylolisthesis was significantly lower than that following fusion for degenerative spondylolisthesis (p=0.037): 1.0%(0.4-1.6) vs. 2.2%(0.7-3.6), respectively.
In conclusion, approximately 1 in 4 patients may require further surgery for ASD within 10 years of undergoing posterior lumbar arthrodesis (PLIF) for degenerative disease. The prevalence varies however with the number of levels fused and the condition treated. It is lowest (10%) following 1-level fusion for lytic spondylolisthesis and highest (40%) following 3 or 4-level fusion.