The Parameter Of Osseous Structure Play Roles On Progression Of Isthmic Spondylolisthesis In Adults

Objective: To analyse the parameter of osseous structure such as lumbosacral angle, slipping angle and shearing force angle play roles on progression of isthmic spondylolisthesis in adults. By vitodynamics testing and clinic following-up. Methods: The lumbosacral spine of six fresh cadaveric specimens from L₄ to S₂ were obtained. The age at time of death ranged from 28 to 51 years old. The average age was 39 years old. The specimens were carefully dissected with preservation of supraspinale ligament, interspinal ligaments, anterior longitudinal ligaments and posterior longitudinal ligaments. The lumbosacral spines were double-bagged and frozen at -20oC until the day testing. The time of preservation was from 12 to 109 days,with the average time of 62 days. All specimens were evaluated radio-graphically before testing. All specimens were proved without abnormal osseous structures. Using a polyester fixating medium, each specimen was embedded at L₄ vertebra and part of L₅ vertebra superiorly and at S₂ vertebra and part of S₁ vertebra inferiorly. According to Crawford and Panjabi method, each specimen was transected supraspinale ligament, interspinal ligaments and arcuate ligaments. The L₅ isthmic part and L₅-S₁ articular capsule was disassociated. The disckectomy was made through lateral spine. Anterior and posterior longitudinal ligament were decoherenced. The mode of isthmic spondylolisthesis was made. In order to reduce the viscoelasticity of specimen effecting to the results, five loads were made before experiment. The testing sequence was taken based on 4 line of random arrangement table, the group with odd number was tested under the sequence of angle from large to little, and tested again under the sequence of angle from little to large, the average was made from the two results under the same angle. ,the group with even number was tested under the sequence of angle from little to large, and tested again under the sequence of angle from large to little, the average was made from the two results under the same angle. Each specimen were subjected to 265N with a load speed of 0.2mm/min and moving range of 50mm.The load was made under even speed in vivo experiment. The feeler searcher was linked to computer, the movement-load curve was recorded. Each test under the same angle was repeated for 3 cycles, the third cycle result was used for analysis. The mark for parameter of osseous structure: The angle between long axis of five lumbar body and long axis of sacral vertebra was called lumbosacral angle. because sacral vertebra is curve, the convenient way is drawing a straight line which perpendicular upper end-plate of the first sacral vertebra, and lumbosacral angle is described as the angle between the line and this line and long axis of five lumbar body .The angle between parallel line of inferior end-plate of the five lumbarvertebra and parallel line of upper end-plate of the first sacral vertebra was called slip angle. The angle between the line which linking the midpoint of five lumbar vertebra and the midpoint of first sacral vertebra and weight line was called shearing force angle. The results of experiment were taken by figure camera. The angle and slippage of vertebra were measured by software of AutoCAD 2004 in computer. The average of results at different testing sequence in the same angle, was analyzed by two-way ANOVA and SNK-q testing. Statistical significance for the test was set at P<0.05. Clinical following:107 cases of spondylolysis or â… o spondylolisthesis were followed-up between February 2003 and January 2005.The people with continuous intact radiograph were 82.According to Meyerding spondylolisthesis classifica-tion, all of the followed-up people was spondylolysis or â… o spondylolisthesis. Cases of spondylolysis were 23,and cases of â… o spondylolisthesis were 59.male 52,female 30.aged at 31 to 50 years old, with the average of 41 years old. All cases were taken radiograph of obverse, lateral and ambi-oblique position, the spondylolysis was valided. The groups were individually divided by the size of lumbosacral angle, slip angle and shearing force angle. A₁ group was included 42 cases with the lumbosacral angle more than 40o, A₂ group was included 40 cases with the lumbosacral angle equal or less than 40o. B₁ group was included 30cases with the slip angle more than 5o, B₂ group was included 52 cases with the slip angle equal or lessthan 5o. C1 group was included 47 cases with the shearing force angle more than 40o, C2 group was included 35 cases with the shearing force angle equal or less than 40o.The followed-up time was from 3 months to 2 years, with the average of 1.8 years. Questionnaire and periodic inspection were taken semiannually at one time. According to Boxall defined the development of spondylolisthesis, increasing slippage no less than 10% or the change of slip angle no less than and both of the two was considered as development of spondylolisthesis. because slip angle was evaluated as a parameter, Only slip increase was considered as development of spondylolisthesis in this study. All of the continuous radiograph was put in computer, the angle and slippage of vertebra were measured by software of AutoCAD 2004.The results of clinical group in different angle were analyzed by chi-square test in SPSS10.0 software. Statistical significance for the test was set at P<0.05. Results: (1)Biomechanical result: â‘ Five lumbar vertebra was slipped forward with the average of 18.6mm, 20.1mm, 23.5mm, 24.8mm, 25.9mm at lumbosacral angle of 30o, 35o, 40o, 45o, 50o, was analyzed by two-way ANOVA with significant different, and SNK-q testing was made. The lumbar vertebra slippage at 30o and 35o was no statistical different. The lumbar vertebra slippage at 40o, 45o and 50o was no statistical different. The lumbar vertebra slippage between 30o, 35oand 40o, 45o, 50o was significant different. â‘¡Five lumbar vertebra was slipped forward with the average of 10.87mm, 10.91mm,11.30mm, 11.55mm at slip angle of -5o, 0o, 5o, 10o, was analyzed by two-way ANOVA with no statistical different. â‘¢Five lumbar vertebra was slipped forward with the average of 18.61mm, 19.42mm, 23.07mm, 24.58mm at shearing force angle of 30o, 35o, 40o, 45o, 50o, was analyzed by two-way ANOVA with significant different, and SNK-q testing was made. The lumbar vertebra slippage at 30o and 35o was no statistical different. The lumbar vertebra slippage at 40o, 45o and 50o was no statistical different. The lumbar vertebra slippage between 30o, 35oand 40o, 45o, 50o was significant different. (2) Clinical result: â‘ 13 of the 41 cases with lumbosacral angle more than 40o were found progression of spondylolisthesis, the incidence of development was 30.95%, 5 of the 40 cases with lumbosacral angle less than or equal 40o were found progression of spondylolisthesis, the incidence of development was 16.67%, were analyzed by chi-square test with significant different(P<0.05). â‘¡6 of the 30 cases with slip angle more than 5o were found progression of spondylolisthesis, the incidence of development was 20.00%, 12 of the 52 cases with slip angle less than or equal 5o were found progression of spondylolisthesis, the incidence of development was 23.08%, were analyzed by chi-square test with no statistical differen(tP>0.05). â‘¢16 of the 47 cases with shearing force angle more than 40o were found progression of spondylolisthesis, the incidence of development was 34.04%, 2 of the 35 cases with shearing force angle less than or equal 40o were found progression of spondylolisthesis,...