Anatomical And Clinical Research Of The Full-Endoscopic Interlaminar Approach For Lower Lumbar Disc Herniations

Object:Conventional open discectomy procedures may result subsequent damage due to trauma which lead to epidural scarring, surgery-induced instabilities.Endoscopic techniques can reduce tissue damage and epidural scarring.With the transforaminal and MED techniques,this procedures are available for lumbar disc operations.But at L5/S1 levels the transforaminal approach may be impeded at the caudal level by the pelvis.The newly developed full-endoscopic Interlaminar Approach is less traumatic than MED techniques.To discuss whether this techniques is applicable in our country,this research is focused on anatomical and clinical statistic of using full-endoscopic interlaminar approach.Methods:1.Diagnosis 16 adult human specimens and measure the following statisticL3/4,L4/5,LS/S1:interlaminar window's square meter and width,distance between lower limb of the spinous process and adjacent top range of vertebral lamina,the length of vertebral lamina,the thickness of vertebral lamina.Then we using the working tube to carried on model experiments.2.A retrospective study of 20 cases which had been carried out Full-Endoscopic Interlaminar Approach for the treatment of lumbar disc hemation during Sep.2008 to Feb.2009.There are 11 males and 9 females,the age ranged from 15～51 years,(mean 32 years).All patients belongs to single level LDH,18 cases in L5/S1,2 cases in L4/5.The mean course of disease was 3.9 months.All patients presented with back pain and ischialgia which underwent MRI examination before surgery.The pathologies typing:13 lateral prolapsed,5 paracenter prolapsed and 2 sequestration.The study parameters including operation time,amount of bleeding,complication and clinical outcome.The following measuring instruments were used VAS legs pain and Oswestry back pain Questionnaire.Result:Distance between lower limb of the spinous process and adjacent top range of vertebral lamina:L3:6.34±2.06mm,L4:7.54±1.15mm L5:6.81±0.33mm,lower limb of the spinous process can be one sign of the interlaminar window on the surface of body.Interlaminar window's width:L3/4:20.65±2.97mm,L4/5 21.27±3.63mm,L5/S1:26.64±4.33mm. Interlaminar window's square meter:L3/4 218.06±11.43mm~2,L4/5 244.38±7.56mm~2,L5/S1 280.75±6.18mm~2.Interlaminar window's square meter and width are increasing from L3 to L5,the working tube is suitable for both side of the windows.The thickness of vertebral lamina at L3:9.90±0.75mm,L4:7.30±0.99mm,L5:6.18±0.71mm.Length of vertebral:L3:24.41±0.98mm,L4:21.42±1.48mm,L5:20.20±1.22mm.At L4/5 and L5/S1 level we found a quadrant as lower zygapophyseal joints.The never roots of right side belongs to partⅢand partⅥ,on the other side the never root belongs to partⅠand partⅡ.Then we put working tube into the interlaminar windows to observe the quadrant of the tube,the right side still at partⅢand partⅥ,the right side at partⅠand partⅡ.Clinical study:20 patients are single level pathological changes according to MRI test,there was little bleeding we could ignored,3 cases turned to mini-open access,2 cases occurred dural injury.There was no serious complication such as postoperative bleeding,Positioning error and nerve injury.Mean hospital stays was 7 days,no infections,19 cases didn't have leg pain when they leave hospital,1 case got relief.The mean following time was 5.8 months(3～9month)and didn't have recurrence case.VAS legs pain and Oswestry back pain Questionnaire:The values of preoperative compared with postoperative 3 months had significantly difference(P＜0.01),the values of last follow-up compared with postoperative 3 months had no difference(P＞0.05)Conclusion:Full-Endoscopic Interlaminar Approach for the surgical treatment of lower lumbar disc herniation have good clinical outcome at L4/5 and L5/S1 levels,this technique is feasible to adult according to the anatomical research.However at the beginning of this technique,this procedure could have a sharp learning-curves,the long-term clinical outcome still under discussion...