Long-term Radiological Changes And Clinical Effect After Microendoscopic Discectomy (MED):A Cross-sectional Study

OBJECTIVE:This study was designed to evaluate post-operative radiological changes and to assess the risk of post-operative back pain in patients who underwent microendoscopic discectomy(MED).METHODS:We classified 132 patients into three groups based on follow-up duration.The patients in Groups 1-3 were followed up for Group 1(42 patients)0-5,Group2(48 patients)5-10,and Group3(42 patients)10?15 years,respectively.Their clinical outcomes were assessed based on their self-reported scores on visual analog scales(VASs)to quantify back pain.Twelve radiological parameters indicating degenerative changes or instability in the operated segments were recorded at various time points.The patients were further classified into two groups based on their VASs:those with back pain and those without back pain(The patients whose VAS scores was higher than 3 points was considered as the back pain group).The independent risk factors for post-MED back pain were identified through bivariate logistic regression from among the risk factors selected via univariate analysis.The identified risk factors were then used to develop a scoring system that used regression coefficients to predict the probability of post-MED back pain.RESULTS:On the clinical effect assessment,the mean VAS scores for back pain in Groups 1?3 were 1.62±0.69,2.81±1.44,and 3.07 ± 1.16,respectively.The scores in Group 1 differed significantly from those of Groups 2 and 3(P<0.01).On the radiological assessments,the mean posterior disc height ratios(PDHRs)in Groups 1?3 were 0.77 ± 0.21,0.72 ±0.18,and 0.67±0.22,respectively(P?0.01).A traction spur was observed in 17 of the 42 patients in Group 1,in 46 of the 48 patients in Group 2,and in 40 of the 42 patients in Group 3(P<0.01).Lateral listhesis was detected in 1 of the 42 patients in Group 1 and in 4 of the 42 patients in Group 3(P ?0.04).Modic type 1 changes were observed in 15(36%)patients in Group 1,18(38%)patients in Group 2,and 5(12%)patients in Group 3(P = 0.01).Modic type 2 changes were found in 5(12%)patients in Group 1,18(38%)patients in Group 2,and 16(38%)patients in Group 3(P = 0.01).Modic type 3 changes were observed in 3(7%)patients in Group 3(P<0.01).Other radiological parameters showed no significant differences.PDHR,traction spur,Modic changes,and lateral listhesis were considered the independent risk factors for post-MED back pain.The established system was then utilized to divide the patients into two groups:-6.55 to-3.58 and>-3.58 points on the probability of post-surgical back pain.The accuracy of the scoring system was 62%.CONCLUSION:This cross-sectional study demonstrated that clinical effect deteriorates over time.High back pain scores corresponded to exacerbating clinical outcomes,and this condition was correlated with radiological findings of degeneration in the operated segments.