The Imageology Localization Of Lumbosacral Vertebrae Of Microendoscopic Disectomy And Its Clinical Application

Objective:To study the imageology relation of space between lumbar vertebral body,lamina of lumbar vertebral arch and lumbar spinous process in different position to guide the accurate pre-operative and operative localization of MED and provide quantized data of operation of lumbar interlaminar space for MED.Methods:83 cases of lumbar disc herniation treated by MED were selected,All of which have taken both AP and lateral radiographs respectively in common posture and in sham operated posture.On the AP radiographs the following data have been measured:1.the vertical distance(d)from the lower edges of the vertebral body to the inferior edge of the root of the same lumbar spinous process;2.the sagittal diameter and transverse diameter of lumbar interlaminar space and.the abducent angle of lumbar vertebral plate.Statistical analysis was done by comparing these values in common posture team with those of in sham operated posture.While on the lateral radiographs the following data have been measured:1 the angle between the bisection line of space of lumbar vertebral body and the perpendicular of horizontal plane from L_1/2to L₅/S;2.the part of spinous process cut by the extension line of the bisection line of lumbar vertebral body space from L_1/2to L₅/S₁;3.the vertical distance from the center point of space between spinous processes to the extension line of the bisection line of lumbar vertebral body space from L_1/2to L₅/S₁.Statistical analysis was also done by comparing these values in common posture team with those of in sham operated posture.According to the localization of radiographs in sham operated posture,puncture of MED operations was carried out and confirmed by C-arm.Results:1.AP radiographs in sham operated posture show that.the vertical distance(d)from the lower edge of the vertebral body to the inferior edge of the root of the same lumbar spinous process of L₁,L₃,L₅ is 8.50±2.17mm,7.53±2.50mm,and -1.50±3.05mm respectively and gradually becomes smaller from L₁ to L₅,the sagittal diameters of lumbar interlaminar space of L_1/2,L_3/4,L₅/s₁ is 15.35±2.27mm,16.15±2.50mm,and 21.25±4.62mm respectively;the transverse diameter of lumbar interlaminar space of L_1/2,L_3/4,L₅/s₁ is 18.52±2.65mm,21.35±3.13mm,and31.65±5.48mm respectively,the abducent angle of lumbar vertebral plate in the left of L_1/2,L_3/4,L₅/s₁ is 47.53±6.12°,51.73±7.25°,and 55.85±7.59°respectively,all of which became larger and larger from L₁ to L₅.There isn't statistical significance by comparing the abducent angle of lumbar vertebral plate of the right side with the left.2 lateral radiographs in sham operated posture show the angle between the bisection line of space of lumbar vertebral body and the perpendicular of horizontal plane changes from tail angle of dip to head angle of dip from L₁ to L₅,angleα₁ is -7.0±2.7°,α₅ is 19.3±4.1°;the part of spinous process cut by the extension line of the bisection line of lumbar vertebral body space become upper and upper from L₁ to L₅;the vertical distance from the center point of space between spinous processes to the extension line of the bisection line of lumbar vertebral body space of L₁,L₃,L₅ is 7.01±1.85mm,10.58±1.73mm,and 12.00±1.05mm respectively,it becomes bigger gradually from L₁ to L₅.3 On AP and lateral radiographs in sham operated postur all of them are different. There are statistically significance(p＜0.05).4.83 cases(87 interspinal spaces)were undergone this kind of surgery and the 1 set correct puncture rate was 97.60%.Conclusions:1.It is a wise choice to take the inferior or middle one third portion of the spinous process as the level of localization and keep a tail angle of dip 1～10°when lumbar disc herniation of L1/2 to L3/4 is treated by MED while the upper or middle one third portion of the spinous process should be choosed as the level of localization and keep a head angle of dip L_4/5:1～5°;L₅/S₁.15～23°when dealing with lumbar disc herniation of L_4/5and L₅/S₁.2.Nearly 5 to 10 mm of the inferior part of lumbar vertebral plate and 3 or 4 mm of the medial border of the inferior articular process should be removed,when carrying out the MED operation of L_1/2～L_3/4.As for the operation of lower lumbar disc herniation, 38 segments of intervertebral space in L4/5 need excise part of the inferior part of lumbar vertebral plate and the medial border of the inferior articular process to expose the space,37segments of intervertebral space in L₅/S₁ need not excise lumbar vertebral plate.3 Radiographs in common posture can not be used as the evidence of precise localization of MED.4.It is a practical and reliable localization method to take photographs in sham operated posture when perform MED.