Clinical Application of Transforaminal Percutaneous Endoscopic Lumbar Discectomy Via Superior Notch of Inferior Vertebral Pedicle Approach for Very High-grade Inferiorly Migrated Disc Herniation

Abstract Background: To assess the efficacy of the superior notch of inferior vertebral pedicle approach of transforaminal percutaneous endoscopic lumbar discectomy for very high-grade inferiorly migrated disc herniation.Methods: Data on 32 consecutive patients operated with percutaneous endoscopic surgery via the superior notch of inferior vertebral pedicle approach were reviewed. Age, gender, clinical diagnoses, operation time, hospitalization time, a self-administered questionnaire composed of the leg pain visual analogue scale (VAS leg pain) and the Oswestry Disability Index (ODI) had been recorded before operation and 1, 3, 6 and 12 months after operation, respectively. The clinical results were assessed at the final follow-up by using modified Macnab criteria. Complications were recorded during follow-up, and postoperative X-ray, CT and MRI examinations were performed.Results: There were 21 males and 11 females. The mean age of patients was 51.8±10.6 years. MRI findings of patients with disc herniation were L2-3 level in 4 case, L3-4 level in 9 cases and L4-5 level in 19 cases, which were correlated with clinical symptoms. All patients completed a 12-month follow-up assessment after surgery. The mean operative duration was 68.2±12.8 min, and hospitalization time was 3.6±0.8 days. At 12 months follow up the VAS leg pain had improved by 6.3 (P< 0.05) and the ODI by 43.6 points (P< 0.05). Twenty-three cases (71.9%) were rated as excellent, 7 (21.9%) as good, 2 (6.2%) as fair at the final follow-up. On the basis of the modified MacNab criteria, the overall excellent and good rate was 93.8%. Two patients (6.2%) had transient dysesthesia after surgery. Postoperative radiological evaluations showed no signs of instability or recurrence of pathology.Conclusion: Transforaminal percutaneous endoscopic lumbar discectomy via the superior notch of inferior vertebral pedicle approach could be a safe and effective minimally invasive technique for very high-grade inferiorly migrated disc herniation. This technique warrants further study and clinical application.