Clinical And Applied Anatomical Study On Percutaneous Endoscopic Lumbar Discectomy

BackgroudsLumbar disc herniation is a common disease causing the low-back pain and sciatica.10%-20%of patients who did not improve after conservative treatment accept surgical management.In 1997,Yeung first reported that patients underwent Percutaneous endoscopic lumbar discectomy(PELD) using Yeung endoscopic spine systerm(YESS) instruments.The clinical outcomes of PELD were satisfied.PELD has been developed recently in China,but the clinical research about PELD was rare. Lumbar discography is only an efficient and safe method of diagnosing with discogenic low back pain.Lumbar discography is routinely performed before PELD, fluoroscopic monitoring after lumbar discography was essential to observe the degeneration of nucleus and integrity of annular fibrosus.In addition,Discography was operated by using methylene blue for the staining of the disc material,which is useful to guide the extent of discectomy.Lumbar disc herniation at L3/4,L4/5 levels was suitable for PELD.LS/S1 disc is thought to be inaccessible or inadequately accessed by the endoscopic technique due to the high iliac crest,so herniations with high iliac crest at L5/S1 level may be excluded from PELD. The purpose of this study was to analyses the surgical outcomes and the cliniacl application of PELD.Because access to the L5/S1 level can be difficult,the objective of this study was to perform the anatomical study of L5-S1 segmental and make a comparison between lumbar discography with MRI in diagnosing with lumbar disc degeneration.All above researches were to provide theory foundation for the clinical application of PELD.Objectives1.To investigate the clinical outcome,indication,contraindication,complication of PELD and initially evaluate the clinical value of PELD.2.To determine the correlation between discography with MRI in reflecting the lumbar disc degeneration.3.To investigate the adjacent structures of L5-S1 disc and provide anatomic data for PELD through the lateral approach.Materials and Methods1.Fifty-two patients with lumbar disc herniation underwent PELD from March 2006 to decemember 2006.The mean age of the patients was 38.5 years(range17 to 63years).The levels of lumbar disc hemiations were L3/4 in 6 cases,L4/5 in 43 cases, LS/S1 in 3 cases.The median course of disease was 34.5 months(range 3 to 156 months).The patients were evaluated for their pain on a Visual Analog Scale(VAS) and functional assessment by a patient-based questionnaire(Oswestry Disability Index,ODI).2.Seventy-four lumbar intervertebral discs(L3/L4 13 cases,L4/L5 57 cases,LS/S1,4 cases)of 72 patients(46 men,26 women) were examined from March 2006 to decemember 2007.The mean age of the patients was 38.7 years(range 17 to 65 years).74 intervertebral discs underwent discography guided by fluoroscopy monitoring.This study was to evaluate the degeneration of lumar intervertebral disc from the results of discography and MRI.3.This study was to study 21 human cadavers to record their adjacent strucutres of lower L5-S1 disc and investigate the feasibility of lateral approach into the L5/S1 disc.Results1.All the patients were performed with PELD successfully.The average period of follow up were 15.4 months(range 12 to 24 months).The mean operative time was 68.1 mins(range 40 to130mins);the mean blood loss was 9.4 ml(range 1 to 50 ml); the mean hospital time was 7 days(range 5 to 12 days).Mean VAS score for back pain improved from7.8 to 0.5,mean VAS score for leg pain improved from 7.3 to 0.6, mean ODI imprvoed from 63 to 19.The improvements in VAS and ODI were statistically significant(P=0.000).Based on the MacNab criteria,90.3%showed excellent outcomes,3.8%showed good outcomes,3.8%showed fair outcomes,2.1% showed poor outcomes.2.Lumbar Modic endplate classification:Type 0,41 discs;Typeâ… ,10 discs;Typeâ…¡, 13 discs;Typeâ…¢,10 discs;The grade of lumbar disc degeneration from the results of lumbar discography:Grade 1,34discs;Grade 2,6 discs;Grade 3,10 discs;Grade 4,11 discs;Grade 5,3 discs;The grade of lumbar disc degeneration based on the results of MRI:Gradel,13 discs;Grade2,48 discs;Grade3,13 discs.There was positive correlation between the Modic degeneration of lumbar endplate on the basis of MRI with the disc degeneration of lumbar intervertebral observed on fluoroscopy discography(r=0.785,P=0.000);There was positive correlation between the disc degeneration of lumbar intervertebral from MRI with the disc degeneration of lumbar intervertebral from discography(r=0.728,P=0.000),There was positive correlation between the disc degeneration of lumbar intervertebral observed on MRI with the Modic degeneration of lumbar end-plate observed on MRI(r=0.616,P=0.000). 3.There is a safety region in lateral suface of the L5-S1 disc,the left region is bigger than the right region.Conclusions1.PELD is suitable for lumbar disc herniation with the advantages of smaller incision,less bleeding,less tissue trauma,better visual exposure,more careful manipulation and quicker recovery,therefore PELD is safe and effective technique in the treatment of lumbar disc herniation.2.Lumbar discography may reflect intervertebral disc degeneration pathology,and is an efficient and safe assistant diagnostic tools for discogenic low pain.There was positive association between the degeneration of lumbar endplate with the disc degeneration of lumbar intervertebral.3.Lateral area of the L5-S1 disc can be used as an alternative target region for the treatment of intervertebral disc disease.It is possible to peform the PELD in the L5/S1 segment through the lateral approach.