Applied Anatomy And Clinical Effect Study Of The Multifidus Gap TLIF Approach In Treatment Of Lumbar Spondylolisthesis

Objective:1. To observe the anatomy of Wiltse gap and multifidus gap and tomeasure the date of MRI for the clinical application.2. To evaluate clinical effect intreatment of lumbar spondylolisthesis of the multifidus gap and the traditional openTLIF approach.Materials and methods:1. Ten formalin-management adult cadavers withcomplete spine were dissected to observe morphology of the thoraolumbar fascia,longest muscle and multifidus muscle. Measurement of the distance which theoutermost edge of the multifidus muscle and the facet to the middleline of L3-S1segment. Thirty sets of the MRI with L3-S1segment cross-pedicle sectional sliceswere selected for measurement of the length of operation channel and the tilt angle ofthe operation channel. The distance between skin surface of the outermost edge of theparaspinal muscle and the root of the transverse process represents the operationchannel length. The angle between the operation channel and the sagittal plane of thespine was measured to represent the operation tilt angle.2. Seventy patients withlumbar spondylolisthesis were selected according to the inclusion criteria. Thirty-fourof whom underwent traditional open TLIF (group A), another36underwent theparaspinal approach TLIF (group B). The follow-up was carried out for2years. Theoperation time, intraoperative blood loss, postoperative complications, fusion rate,VAS score and ODI scores were recorded and statistically analyzed.Results:1. There is a natural gap between multifidus muscle and longest muscle,which is covered by longest muscle at the lumbosacral segment. Part of surfacemultifidus muscle bundles are intertwined with longest muscle. The distance whichthe outermost edge of the multifidus muscle to the middleline is26.84±3.34mm-33.48±3.01mm; the distance which the facet to the middleline is23.17±1.35mm-31.89±1.47mm. The operation channel length range from70mm to65mm. The tiltangle of operation channel is12.63±1.75°-14.84±1.58°.2. VAS and ODI scores of last follow-up of two groups, were significantly improved compared with thepreoperative (p <0.001). VAS scores of group A and group B were7.2±2.3,4.5±1.8(p <0.001) on third postoperative day; ODI score of group A and group B on thirtythpostoperative day were32%±10.5,18%±6.1%(p <0.001). VAS score and ODIscore in group B have a more quicker recovery in the early. Long-term follow-upresults showed no statistically significant in two groups. The average blood loss ofgroup A and group B were620±46ml、230±39ml (p <0.001); Averagepostoperative drainage were290±69ml、120±40ml (p <0.05) in group A andgroup B; Average length of hospital stay were7.4±1.5d、4.1±1.2d (p <0.05);Conclusion:1. There is a natural gap between the multifidus muscle and thelongissimus. The facet and transverse roots can be directly reached through the gap.The outermost edge of the multifidus muscle and the facet to the middleline of L3-S1segment, the operation channel length and the tilt angle of the operation channel, theycan be used for the guideline of the multifidus muscle gap approach.2. Comparedwith the traditional open TLIF surgery, the multifidus muscle gap approach TLIFsurgery show the same clinical efficacy. However, shorter incision, less multifidusmuscle damage, less bleeding, faster recovery in the perioperation period show is aminimally invasive by the multifidus muscle gap approach TLIF surgery.