The Clinical Study On Adjacent Segment Degeneration Following Posterior Instrumental Lumbar Fusion:Floating Fusion Versus Lumbosacral Fusion

ObjectiveTo contrast mid-term outcome towards degenerative lumbar disease of lumbar floating fusion and lumbaosacral fusion,and study their different influence factors of postoperative adjacent segment degeneration or adjacent segment disease.MethodsPatients who were diagnosed with degenerative lumbar disease(including lumbar disc herniation,lumbar spinal stenosis or lumbar spondylolisthesis)and underwent lumbar posterior operation in Guangdong Province Hospital of TCM from January 2010 to November 2014 were investigated.84 patients conformed to the selected conditions were collected,divided into two groups,42 cases in observation group(lumbar floating fusion)and 42 cases in matched group(lumbaosacral fusion).The Visual Analogue Scale(VAS),Japanese Orthopaedic Association Scores(JOA)were used to evaluated postoperative clinical effects for two groups.The upper and below adjacent segment degeneration(ASDeg)and adjacent segment disease(ASDis)were evaluated by measuring the height of intervertebral space and the range of motion,using University of California at Loa Angles Grading Scale(UCLA)on X-ray radiography.Several radiographic parameters were measured on pre-and postoperative radiographs,including lumbar lordosis(LL),pelvic incidence(PI),and pelvic incidence-lumbar lordosis(?PILL).To record the above-mentioned index of two groups,Excel 2007 software was used to establish a database and SPSS Statistics 21.0 statistical software was used to analyze this database.P<0.05 was considered as statistically significant.ResultsThe general information of observation group(lumbar floating fusion)and control group(lumbaosacral fusion)has no statistical difference in the comparison,which prompts comparable between the two sets of data.Including age,sex ratio,BMI,course of disease,operation time,hospitalization time,follow up period,intraoperative blood loss and distribution of cases.The observation group of preoperative JOA score:16.98 ± 2.25,preoperative lumbago VAS score:3.74 ± 1.70,preoperative skelalgia VAS score:5.05 ± 1.51;the control group of preoperative JOA score:16.93 ± 2.68,preoperative lumbago VAS score:3.96+2.03,preoperative skelalgia VAS score:5.12 ± 1.48;after the comparison,preoperative VAS and JOA score was no significant difference(P>0.05).While in the last follow-up period,the observation group,postoperative lumbago VAS score and postoperative skelalgia VAS score were:25.17 ± 1.78,0.68 ± 0.56 and 0.76 ± 0.59,respectively;of the control group they were 24.97±1 65,0.67±0.60 and 0.83±0.56,respectively.After midterm follow-up,comparing differences were statistically significant(P<0.01).During the follow-up period,a total of 34 cases with adjacent segment degeneration were clarified,occurred in the postoperative follow-up of 24.50± 12.95 months.In the observation group,the incidence of ASDeg was 26.19%(11 out of 42),the incidence of ASDis was 19.05%(8 out of 42),and 1 patient received revision surgery due to the obvious symptoms of ASDis.While in the control group,the morbidity of ASDeg was 4.76%(2 out of 42),30.95%patients suffered from ASDis(13 out of 42),and 3 patients received revision surgery because of the obvious radicular symptom.With the pelvic incidence-lumbar lordosis mismatch predisposes to adjacent segment degeneration,the receiver-operating characteristic curve of the AUC area,sensitivity,specificity,positive predictive value,negative predictive value of ?PILL were 0.797,85.7%,75.7%,87.3%,93.1%,respectively.Take the best point of 19.10 for grouping,in the ?PILL<19.10 group,the incidence of ASDeg was 12.7%,while in the APILL>19.1°group,the incidence of ASDeg raised up to 93.1%?The comparing difference was statistically significant(P<0.01).ConclusionBoth lumbar floating fusion and lumbosacral fusion can obtain good therapeutic effect in treatment of degenerative lumbar disease(LDH?LSS or spondylolisthesis)during a midterm follow-up,and these two operation methods got similar effect.Either of each method fails to prevent patients from ASDeg.Patients who had floating lumbar fusion were statistically more likely to develop radiological ASD over time than those who had lumbosacral fusion incorporating the S1 spinal segment,but were less likely to experience postoperative radicular symptom.Patients with obviously mismatched pelvic incidence-lumbar lordosis exhibit higher risk for developing postoperative ASDeg or ASDis.