Radiological and clinical outcomes of midline lumbar fusion on sagittal lumbar-pelvic parameters for degenerative lumbar diseases

BACKGROUND Improving the sagittal lumbar-pelvic parameters after fusion surgery is important for improving clinical outcomes.The impact of midline lumbar fusion(MIDLF)on sagittal lumbar-pelvic alignment for the management of degenerative lumbar diseases is still unknown.AIM To analyze the effects of short-segment MIDLF and minimally invasive transforaminal lumbar interbody fusion(MIS-TLIF)on sagittal lumbar-pelvic parameters.METHODS We retrospectively analyzed 63 patients with degenerative lumbar diseases who underwent single-segment MIDLF or MIS-TLIF.The imaging data of patients were collected before surgery and at the final follow-up.The radiological sagittal parameters included the lumbar lordosis(LL),lower LL,L4 slope(L4S),L5 slope(L5S),L5 incidence(L5I),L1 axis and S1 distance(LASD),pelvic incidence(PI),pelvic tilt(PT),sacral slope(SS),and PI-LL mismatch(PI-LL).Additionally,the clinical outcomes,including lower back and leg pain visual analog scale(VAS)and Oswestry disability index(ODI)scores,were also analyzed.RESULTS In both groups,LL and Lower LL significantly increased,while L5I and LASD significantly decreased at the final follow-up compared to that recorded prior to operation(P<0.05).In the MIDLF group,L4S significantly decreased compared to that recorded prior to operation(P<0.05),while the mean SS significantly increased and the PT significantly decreased compared to that recorded prior to operation(P<0.05).In the MIS-TLIF group,SS slightly increased and the mean PT value decreased compared to that recorded prior to operation,but without a statistically significant difference(P>0.05).However,the PI-LL in both groups was significantly reduced compared to that recorded prior to operation(P<0.05).There was no significant difference in the sagittal lumbar-pelvic parameters between the two groups prior to operation and at the final follow-up(P>0.05).In addition,the change in sagittal lumbar-pelvic parameters did not differ significantly,except forΔLASD within the two groups(P>0.05).The mean lower back and leg pain VAS and ODI scores in both groups were significantly improved three months after surgery and at the final follow-up.Though the mean ODI score in the MIDLF group three months after surgery was slightly higher than that in the MIS-TLIF group,there was no significant difference between the two groups at the final follow-up.CONCLUSION Short-segment MIDLF and MIS-TLIF can equally improve sagittal lumbar parameters such as LL,Lower LL,L5I,and LASD in the treatment of lumbar degenerative diseases.However,MIDLF had a larger impact on pelvic parameters than MIS-TLIF.

Differences of Sagittal Lumbosacral Parameters between Patients with Lumbar Spondylolysis and Normal Adults

Background： Recent studies have suggested an association between elevated pelvic incidence （PI） and the development of lumbar spondylolysis. However, there is still lack of investigation for Hart Chinese people concerning the normal range ofspinopelvic parameters and relationship between abnormal sagittal parameters and lumbar diseases. The objective of the study was to investigate sagittal lumbosacral parameters of adult lumbar spondylolysis patients in Han Chinese population. Methods： A total of 52 adult patients with symptomatic lumbar spondylolysis treated in the General Hospital of Armed Police Force （Beijing, China） were identified as the spondylolysis group. All the 52 patients were divided into two subgroups, Subgroup A： 36 patients with simple lumbar spondylolysis, and Subgroup B： 16 patients with lumbar spondylolysis accompanying with mild lumbar spondylolisthesis （slip percentage 〈30%）. Altogether 207 healthy adults were chosen as the control group. All patients and the control group took lumbosacral lateral radiographs. Seven sagittal lumbosacral parameters, including PI, pelvic tilt （PT）, sacral slope （SS）, lumbar lordosis （LL）, L5 incidence, L5 slope, and sacral table angle （STA）, were measured in the lateral radiographs. All the parameters aforementioned were compared between the two subgroups and between the spondylolysis group and the control group with independent-sample t-test. Results： There were no statistically significant differences of all seven sagittal lumbosacral parameters between Subgroup A and Subgroup B. PI, PT, SS, and LL were higher （P 〈 0.05） in the spondylolysis group than those in the control group, but STA was lower （P 〈 0.001 ） in the spondylolysis group. Conclusions： Current study results suggest that increased PI and decreased STA may play important roles in the pathology of lumbar spondylolysis in Han Chinese population.