Transforaminal Endoscopic Lumbar Discectomy For Extruded Disc Herniation

Background:The conventional open surgery is the gold standard for treating extruded lumbar disc herniation.Endoscopic spine surgery is known to be very challenging and technically demanding task,particularly for disc herniation with migration.Objective:To assess the clinical results of percutaneous endoscopic lumbar discectomy(Outside-in technique)with additional foraminoplasty before and after the surgery in patients with migrated lumbar disc herniation and investigate the short and long-term clinical outcomes.Methods:A retrospective review was performed on 250 consecutive patients who had undergone PELD(outside-in technique)with additional foraminoplasty between January 2015 and January 2017 at The Affiliated ZhongDa Hospital of Southeast University Spine Surgery Department.Only 68 patients were selected for this study,there were 52 Male and 16 Female mean age 37.3±12.4;range(16-64 y),BMI mean(24.84±3.60)kg/m2.All patients were preoperatively diagnosed with migrated lumbar disc herniation.The Diagnosis was confirmed with MRI(magnetic resonance imaging)and CT scan results.The migration was classified into 3 grades according to the classification proposed by Lee et al:Upward/Downward(very high,high,and low).The surgical outcomes were assessed by visual analogue scale score for back and leg pain,Oswestry Disability Index,and modified MacNab criteria.Patients operative time were also recorded.The follow-up period was 1 year(at 1 month,3 months,6 months,and 12 months post-operative respectively).Results:A total of 68 patients underwent PELD for lumbar migrated disc herniation.There were upward-very high 0 case(0%)upward-low 2 case(2.9%),upward-high 3 cases(4.4%),downward-low 32 cases(47.1%),downward-high 22 cases(32.4%),and downward-very high 9 cases(13.2%),In all cases the herniation was removed with the outside-in technique from L3-4 to L5-S1,with additional foraminoplasty.The mean operative time was 80.88±29.81,preoperative VAS leg(6.07±1.21),VAS back(3.97±2.53)and ODI(35.31±9.63)score decreased,which explains that there is significant improvement at the last follow-up VAS leg(0.49±1.29),VAS back(0.76±1.37);ODI(3.10±6.75)p value<0.05.27 patients(39.7%)preoperatively had numbness,the symptom had improved in 23 patients and 4 patients had poor outcomes.Based on the modified MacNab criteria the outcome at the last follow-up was excellent in 45(66.2%)patients,good in 17(25%),fair in 2(2.9%)and poor in 4(5.9%).Limitations:A small sample size,Short follow upConclusions:the Outside-in technique with additional foraminoplasty for treating extruded lumbar disc herniation,especially in migrated ones is safe and effective,even though it is hard to predict long-term outcome acknowledging that there are factors such as recurrence,surgery-related-complication,and other unforeseen events that can contribute to surgical failures.