Risk-factor analysis of adjacent segment disease requiring surgery after short lumbar fusion: the influence of rheumatoid arthritis

Publication date: Available online 13 February 2018
Source:The Spine Journal
Author(s): Jin-Sung Park, Kyu-Dong Shim, Young-Sik Song, Ye-Soo Park
BACKGROUND CONTEXTThe influence of rheumatoid arthritis (RA) on the lumbar spine has received relatively little attention compared with cervical spine, and few studies have been conducted for adjacent segment disease (ASD) after lumbar fusion in the patients with RA.PURPOSETo determine the incidence of ASD requiring surgery (ASDrS) after short lumbar fusion and to evaluate risk factors of ASDrS, including RA.STUDY DESIGNRetrospective cohort studyPATIENT SAMPLEThis study included 479 patients who underwent lumbar spinal fusion of 3 or fewer levels, with the mean follow-up period of 51.2 months (12 to 132).OUTCOME MEASRUESThe development of ASD and consequent revision surgery were reviewed using follow-up data.METHODSThe ASDrS-free survival rate of adjacent segments was calculated through Kaplan-Meier method. The log-rank test and Cox regression analysis were used to evaluate risk factors, comprising RA, age, sex, obesity, osteoporosis, diabetes, smoking, surgical method, and the number of fusion segments.RESULTSAfter short lumbar fusion, revision surgery for ASD was performed in 37 patients (7.7%). Kaplan-Meier analysis predicted that the ASDrS-free survival rate of adjacent segments was 97.8% at 3-years, 92.7% at 5-years, and 86.8% at 7-years. In risk factor analysis, patients with RA showed a 4.5 times higher risk for ASDrS than patients without RA (p < 0.001), and patients with 3-segment fusion showed a 2.7 times higher risk than 1- or 2-segment fusion (p = 0.005).CONCLUSIONASD requiring surgery was predicted in 13.2% of patients at 7-years after short lumbar fusion. RA and the number of fusion segments were confirmed as risk factors.



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