Outcomes And Outcome Predictors Of Percutaneous Endoscopic Lumbar Discectomy For The Treatment Of Lumbar Disc Hernitation

BackgroundPercutaneous endoscopic lumbar discectomy(PELD)is a popular surgical procedure for the treatment of lumbar disc herniation with radiculopathy.There is a paucity of literature studying efficacy and safety of this surgery.Clinical practice found that a small part of the patients had poor surgical outcomes,but the reasons remain unknown.In this study,we aim to analyze the outcomes of the patients managed by PELD and explore the factors which might affect the outcomes of this surgery.The findings of this study will improve the understanding of the advantages and disadvantages of PELD and help surgeons acquire a clear awareness of the indications and contraindications for PELD so as to reduce incidence of poor outcomes of this surgery.Methods Patients managed by PELD in the authors' institution were reviewed and followed up to 2 years.Their numeric rating scale(NRS)pain scores and Oswestry Disability Index(ODI)scores were analyzed.The complications and their treatments were summarized.The outcomes of the patients were graded as excellengood,fair and poor based on MacNab criteria Their characteristics in clinical history,physical examination,imaging,and surgery were compared between the groups.Univariate analysis and ordinal logistic regression analysis were used to identify independent predictors for outcomes.Regarding to Percutaneous transforaminal endoscopic discectomy(PTED),postoperative intervertebral disc degeneration assessed on magnetic resonance imaging and spinal stability assessed on lateral radiography in flexion and extension planes compared with preoperative values.Results430 patients who had been managed by PELD for lumbar disc herniation with radiculopathy were reviewed.327 patients were included and 103 excluded in the follow-up.241 patients who had completed the follow-up were available for analysis.The mean follow-up period was 23.8±14.8 months.The preoperative mean scares of the total on NRS for back pain NRS for leg pain,and ODI were 4.2±2.6,5.5±2.5 and 50.8±23.7%,2 years after surgery,these scores reduced to 1.2±1.7,0.8±1.5 and 82±10.9%,respectively(P<0.001).The complication rate of PELD was 13.6%.Recurrent lumbar disc herniation and neural injury dominated,occurring in 5.1%and 4.2%of the patents.The reoperation rate was 5.1%.The rates of excellent,good,fair,and poor outcomes were 44.9%,313%,16.8%and 7.0%respectively.Univariate analysis and ordinal logistic regression analysis revealed that two-level PELD(OR=5.3,P=0.001),history of lumbar fusion(OR=8.2,P-0.007),and Modic changes(OR=2.1,P=0.011)were independent predictors for poor outcomes.Numbness was independent predictors for excellent outcomes(OR=0.5,P=0.014).Regarding to PTED,the percentage of degenerated disc was 85.1%preoperatively and increased to 100.0%postoperatively(P=0.002);the percentage of Moid changes was 33.3%preoperatively and increased to 55.6%postoperatively(P=0.031);mean disc height was 13.9±1.6mm preoperatively and decreased to 12.7±2.1mm postoperatively(P=0.001);anterior olisthesis,retro-olisdiesis and segmental range of motion on lateral flexion and extension radiographs were not significantly increased after surgeryConclusionsPELD appears to be an effective surgical treatment for lumbar disc herniation with radiculopathy.It helps the patients relieve pain and inaiease activities.A small part of the patients experience poor surgical outcomes.The main complications are recurrent lumbar disc herniation and neural injury.Two-level PELD,history of lumbar fusion,and Modic changes at the hemiation level are independent predictors for poor outcomes following PELD.Patients of lumbar disc herniation with numbness are likely to have excellent outcomes.PTED may possibly aggravate intervertebral disc degeneration,but it does not lead to spinal instability.