UBE-LIF: First Technical Description

#Citation

Heo DH, Son SK, Eum JH, Park CK. Fully endoscopic lumbar interbody fusion using a percutaneous unilateral biportal endoscopic technique: technical note and preliminary clinical results. Neurosurg Focus. 2017;43(2):E8.

#Overview

At the time of publication, the clinical application of endoscopic spine surgery was largely confined to decompressive procedures such as discectomy and laminotomy. The feasibility of performing interbody fusion using a purely endoscopic approach remained uncertain.

This study presents the first structured technical description of fully endoscopic lumbar interbody fusion using a unilateral biportal endoscopic (UBE) technique, along with preliminary clinical outcomes.

#Key Findings

A total of 69 patients undergoing single-level lumbar fusion (L3–S1) were treated using the UBE approach with a minimum follow-up of 12 months.

The procedure utilized a dual-portal system consisting of a dedicated endoscopic portal and a working portal, allowing decompression, discectomy, endplate preparation, and cage insertion under continuous endoscopic visualization without microscopic assistance.

Postoperative MRI obtained on day 2 confirmed adequate neural decompression in all cases. Significant improvement was observed in both VAS and ODI scores at final follow-up, with no reported postoperative neurological deterioration.

The authors conclude that UBE-based fully endoscopic LIF may serve as a minimally invasive alternative for degenerative lumbar disease, while emphasizing the need for long-term validation.

#Technical Significance

This report establishes the fundamental surgical architecture of UBE-LIF.

The separation of visualization and instrumentation through two independent portals allows unrestricted instrument handling and facilitates the use of conventional spinal instruments. The endoscopic field closely resembles that of microscopic posterior approaches, enabling direct neural decompression comparable to conventional TLIF while minimizing posterior soft tissue injury.

Endplate preparation under direct endoscopic visualization represents a notable technical advantage over other minimally invasive approaches, where preparation is often performed under limited or indirect visualization.

#Methodological Considerations

This study is a single-arm prospective case series without a comparator group. As such, the results should be interpreted as demonstrating procedural feasibility rather than comparative efficacy.

Although the cohort size (n=69) is relatively large for a technical report, the study is limited by its single-center design and potential surgeon-dependent bias.

Importantly, radiographic fusion outcomes were not systematically evaluated, and complication reporting was focused primarily on neurological status, with limited detail on procedure-specific adverse events.

#Clinical Implications

The study expands the scope of endoscopic spine surgery from decompression to fusion.

It demonstrates that single-level lumbar fusion using a fully endoscopic approach is technically feasible and can achieve effective neural decompression with favorable short-term clinical outcomes.

However, its findings remain at the level of feasibility evidence. Clinical decision-making should therefore incorporate higher-level data, including comparative studies and long-term outcome analyses, particularly regarding fusion rates, mechanical stability, and alignment restoration.

#Perspective

This work defines an initial technical framework that has subsequently been refined and expanded in later studies.

While the concept of “fully endoscopic” fusion has evolved with the introduction of hybrid and modified techniques, the present study remains a reference point for the early development of UBE-based interbody fusion.

#Author Note

This review is based on metadata and full-text analysis of a PubMed-indexed publication. It is intended for academic discussion and does not constitute clinical recommendation.