Comparative Study Of Treating Lumbar Spinal Stenosis By Modified PLIF And PLIF

Objective:To compare the clinical outcome and effects of modified posterior lumbar interbodyfusion(MPLIF)and posterior lumbar interbody fusion(PLIF)on lumbar spinalstenosis(LSS).Methods:From June2009to June2010,43patients with LSS were treated by modifiedPLIF(20cases)or PLIF(23cases); There were15males and28females．The age was from51to75years with an average of64.2years;57levels in total were fused including31cases of single level,10cases of double levels and2cases of three levels. X-ray, CT, MRIexamination were undertook for all the cases. We record operation time, bleed amountduring operation, the number of complications, incidence of perioperative complication,rate of interbody fusion; the visual analogue scale(VAS)score system and Oswestrydisability index(ODI)score system were used to evaluate the clinical outcome, and theimprovement rate was calculated; the height of disc space were measured by Robertsmethod at pro-operation and at the end of follow up; the Suk method were used to evaluatethe interbody fusion rate.Results:The incision all healed by first intention. There were avulsions of spinal cord4cases:group modified PLIF1case and group PLIF3cases, which were repaired by usingartificial spinal cord successfully. There were injured nerve3cases: group modified PLIF1case, which was passing; And group PLIF2cases, which remised by closing the nerve root.There was no fracture of the fixation system. The incidence of perioperative complicationin group PLIF(21.7％) was significantly higher than that of group modifiedPLIF(5.0％)(P<0.05). The operation time of modified PLIF was109±17min, bleed amountduring operation was390±53.5ml, rate of interbody fusion was89.3％. The operation timeof PLIF was143±2l min, bleed amount during operation was680±42.4ml, rate of interbody fusion was87.1％. The operation time and bleed amount during operation ofgroup PLIF were obviously higher than that of group modified PLIF(P<0.05). There wereno significant differences between two groups in terms of the rate of interbodyfusion(P>0.05). All of43patients were followed up for12-36months(average20months).At1week after operation, the satisfied rate of patients was90.0％in group modified PLIF,82.6％in group PLIF(P>0.05). There were no significant differences between two groupsin tems of VAS and ODI when compared the preoperative value with the final follow-upvalue (P>0.05). There was significant difference within group modified PLIF and PLIF interms of VAS and ODI when compared the preoperative value with the final follow-upvalue(P<0.05), but there were no significant differences among two groups in theimprovement rate(P>0.05)．The intervertebral space grading method proposed by Robertsmethod was adopted to evaluate the intervertebral space height，the value in groupmodified PLIF was0.80±0.9l at pre-operation，and1.26±0.43at the end of follow up(P<0.05)；the value in group PLIF was0.77±0.90at pre-operation，and1.25±0.58at theend of follow up(p<0.05)．Conclusion:Interbody fusion with either a PLIF or a modified PLIF provides good outcomes inthe treatment of LSS. According to the patients’ frondose condition, we should strictlycontrol the indictions of PLIF and MPLIF, and select the better method. Both PLIF andMPLIF are viable methods in the treatment of LSS.