1. 2017;20;E507-E512Initial Clinical Outcomes of Percutaneous Full-Endoscopic Lumbar Discectomy Using an Interlaminar Approach at the L4-L5
   Retrospective Evaluation
   Kiyoshi Yoshihara, MD, and Jun-ichiro Nakamura, MD.

BACKGROUND: Percutaneous full-endoscopic discectomy (PED) is being increasingly used because of its potential to minimalize soft-tissue damage and decrease hospital stay. PED using the interlaminar approach (PED-IL) at L4-L5 is performed by only a few surgeons. To the best of our knowledge, the safety and efficacy of PED-IL at L4-L5, without experience in PED via a transforaminal approach (PED-TF) has not been previously reported.

OBJECTIVE: This study aimed to evaluate initial clinical outcomes and complications of PED-IL at L4-L5 without experience in PED-TF.

STUDY DESIGN: Retrospective evaluation.

SETTING: An urban minimally invasive spine hospital.

METHODS: Of a total of 50 patients (36 men and 14 women, ages ranging from 21-59 years, with the average age being 40.3 years old), 16 cases were performed at L4-L5 and 34 cases were performed at L5-S1. PED-IL was successfully completed in all cases, and no case required conversion to open surgery. The operative time, hospital stay, modified MacNab criteria, and visual analog scale (VAS) scores were examined at L5-S1 (range: 41-112). There was no significant difference in operative time between the L4-L5 and L5-S1 groups; the operative time was gradually decreased. The mean hospital stay was 2.9 days (range: 2-8 days). According to modified MacNab criteria, 20 cases (6 at L4-L5 and 14 at L5-S1) were excellent, 27 (10 at L4-L5 and 17 at L5-S1) were good, one at L5-S1 was fair, and 2 at L5-S1 were poor. Two perineurium tears occurred at L5-S1. There was no infection or recurrence of herniated nucleus pulposus (HNP). The clinical outcomes of PED-IL at L4-L5 were equal to those at L5- S1.

RESULTS: The mean operative time was 71.3 ± 19.3 minutes for all cases (range: 41-112 mins.),76.1 ± 16.8 minutes at L4-L5 (range: 52-102 mins.), and 70.5 ± 20.1 minutes at L5-S1 (range: 41-112 mins.).

LIMITATIONS: A small sample size and a short follow-up period.

CONCLUSIONS: The clinical outcomes of PED-IL at L4-L5 were equal to those at L5-S1. Therefore, PED-IL is suitable to be a standard method for any type of intracanalicular disc herniation.