Comparative Study Of Unilateral TLIF And Bilateral TLIF On Lumbar Degenerative Disease

ObjectivesOur research includes two parts of biomechanical study and clinical applicative research. The purpose of biomechanical study is to analyze the efficacy of Unilateral TLIF on one-level human cadaveric lumbar spine model. This study is proposed that Unilateral TLIF can achieve identical initial stability to Bilateral TLIF on one-level lumbar fusion segments. What is more, it is expected less change of biomechanical mode at adjacent segments, which can provide theoretical guidance for the clinical application of this technique. The purpose of the clinical study is to discussing the clinical feasibility of Unilateral TLIF on lumbar degenerative disease by reviewing the cases of unilateral TLIF and bilateral TLIF on lumbar degenerative disease, compare the operating time, blood loss, the long-term clinical efficacy, and fusion rates between them.PartⅠBiomechanical StudyMaterials and methodsSix fresh adult cadaveric lumbar spines were tested in such sequential order:A:Intact groupB:Unilateral instability groupC:Bilateral instability group Each specimen was nondestructively tested in flexion-extension, lateral bending, and axial rotation by ElectroForce, which were recorded by a six-camera motion analysis system.Results①Compared with the compact function unit, the ROM in all fixation group are lower clearly, the difference show static significance. (P<0.05)。②The ROM of group C in all working state is lower than group B, the difference show static significance. (P<0.05) PartⅡClinical StudyMaterials and methodsDuring Febuary 2009 and December 2009.40 cases with lumbar degenerative diseases had underwent TLIF surgery in our department. We arranged the patients to unilateral group (Group A) or bilateral group (Group B) by randomize. Among Group A, there were 14 male and 6 female. The mean age was 47.35±14.48. The L4-5 level was involved in 10, the L5-S1 level was involved in 10. Among Group B, there were 8 male and 12 female. The mean age was 46.35±12.42. The L4-5 level was involved in 11, the L5-S1 level was involved in 8, the L1-2 level was involved in 1.All patients experienced a combination of mechanical back pain and unilateral radiculopathy. All patients in Group A were treated with unilateral TLIF.14 of 20 were treated by conventional open approach, and the other 6 were treated by X-tube minimal invasive approach. All patients in Group B were treated with bilateral TLIF.15 of 20 were treated by conventional open approach, and the other 5 were treated by X-tube minimal invasive approach.ResultsThe mean operation duration of Group A was 186.0±36.0 minutes and th e mean blood loss amount was 280.0±20.0 ml. And the mean operation durat ion of Group B was 230±37.5 minutes and the mean blood loss amount was 5 21.5±264.6 ml. Dural tear happened in 1 but no leakage of cerebrospinal fluid happened. Lumbar pain almost eliminated and radicular pain in lower extremity totally disappeared postoperativey. The numbness in lower extr emity disappeared gradually, no worsen numbness and no contralateral radic ulopathy happened postoperatively. The ODI of the patients shows signific ant differences between preparative and 1 week after operative among Grou p A and Group B(P<0.05). The ODI of the patients which collected at 3 mon ths,6months, and 12 months shows no significant differences between Group A and Group B(P>0.05).No cage translation or subsidence occured, and no pedicle screws breakage happened during follow-up. There was no instabil ity sign on dynamic radiographic images. According to sagittal and corona 1 CT imager taken at last follow-up, complete bony fusion was shown in 10, incomplete bony fusion was shown in 2 in Group A, while complete bony fus ion was shown in 11, incomplete bony fusion was shown in 2 in Group B, it shows no significant differences between Group A and Group B(P>0.05) ConelusionsDifferent fixation method all could add the biomechanic stability for minimally invasive TLIF, and the group B>group C. In the minimally invasive TLIF surgical, single cage with same side pedicle screw fixation, the biomechanical strength is adequate.As to the existent slight instability preoperatively, it is effective to perform unilateral TLIF for one-level lumbar degenerative diseases with u nilateral radiculopathy. There is no sign of non fusion or mental failure during our long-term follow-up.