Evaluation of Two Methods (Inside-Out/Outside-In) Inferior Articular Process Resection for Uniportal Full Endoscopic Posterolateral Transforaminal Lumbar Interbody Fusion: Technical Note.

Jun-Hyung Lee,Hyeun-Sung Kim,Myeong-Hun Kim,Il-Tae Jang,Yeon-Jin Lee,Jun-Hyung Lee,Jin-Woo An,Inkyung Lee,Pang-Hung Wu,Jun-Hwan Park,Jong-Sung Park

doi:10.3390/brainsci11091169

Abstract

Objective: There is limited literature comparing the uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion outside-in approach (ETLIF (O)) with the inside-out approach (ETLIF (I)). Methods: Radiological evaluation was performed on disc height restoration and coronal wedging angle, and operation time (inferior articular process resection time/total operation time) and clinical evaluation were made. Result: 48 cases of inside-out and 38 cases of outside-in cases were included. Compared to inside-out, the outside-in approach had significantly less operative time required to resect inferior articular process: 36.55 ± 10.37, and total operative time: 87.45 ± 20.14 min compared to 49.83 ± 23.97 and 102.56 ± 36.53 min, respectively, for the inside-out approach, p < 0.05. Compared to the preoperative state, both cohorts achieved significant improvement of VAS and ODI at post-operative 1 week, 3 months and at final follow up. Both cohorts achieved statistically significant increased disc height with 5.00 ± 2.87 mm, 5.49 ± 2.33 mm and statistically significant improvement in coronal wedge angle with 1.76 ± 1.63°, 3.24 ± 2.92° in the inside-out and outside-in approaches respectively. Conclusions: Complete removal of inferior articular process is the key part of endoscopic fusion with two methods that can be applied: an inside-out approach or an outside-in approach. Comparing both techniques, the outside-in approach has a shorter operative time required for inferior articular process resection and total length of operation with similar good clinical and radiological outcomes.

Highlights

With the evolution of endoscopic spine surgery, there are an increasing variety of endoscopic techniques being applied in lumbar spine surgery [1,2]
There is no direct decompression in KLIF and additional decompression is required if there is significant spinal stenosis
As the subsequent steps in handling of superior articular process, end plate and cage insertion were similar in both ETLIF (I) and ETLIF (O): they both allowed a large cage to be inserted in the intervertebral space. We found both ETLIF approaches to be as proficient in correction of coronal wedge angle, disc height, improving clinical parameters of Visual Analog Scale (VAS) pain score and Oswestry Disability Index (ODI) score with statistical improvement within each cohort compared to pre and postoperative parameters but no statistical difference was found between the two cohorts

Summary

Introduction

With the evolution of endoscopic spine surgery, there are an increasing variety of endoscopic techniques being applied in lumbar spine surgery [1,2] Both transforaminal and interlaminar approaches have been described to treat various degenerative conditions of the lumbar spine [3,4,5,6,7]. Endoscopic lumbar interbody fusion through the transforaminal route in Kambin’s triangle (KLIF) has a relatively longer history than endoscopic lumbar interbody fusion through the posterolateral route (ETLIF). Kim and Wu et al described the uniportal full endoscopic approach to perform posterolateral transforaminal lumbar interbody fusion (ETLIF) with facet resection in grade 2 spondylolisthesis, scoliosis of less than 30◦ curve and severe foraminal stenosis patients [17,18,19]. We performed a retrospective comparative cohort study to evaluate the operative, radiological roentgenogram outcomes and clinical outcomes of ETLIF inside-out, ETLIF (I) as compared to outside-in and ETLIF (O) for single level lumbar interbody fusion

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Discussion

Conclusion