Unilateral Biportal Endoscopic Trans-Kambin Triangle Lumbar Interbody Fusion With an Oblique Lateral Interbody Fusion Cage

Cheng-Ying Lee; Borriwat Santipas; Rohit Akshay Kavishwar; Sagar Gurnani; Hui-Ling Kerr; Cheol-Wung Park

doi:10.21182/jmisst.2024.01928

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Journal of Minimally Invasive Spine Surgery and Technique 2025; 10(2): 285-288.

Published online: October 31, 2025

DOI: https://doi.org/10.21182/jmisst.2024.01928

Unilateral Biportal Endoscopic Trans-Kambin Triangle Lumbar Interbody Fusion With an Oblique Lateral Interbody Fusion Cage

Cheng-Ying Lee¹

, Borriwat Santipas²

, Rohit Akshay Kavishwar³

, Sagar Gurnani⁴

, Hui-Ling Kerr⁵

, Cheol-Wung Park⁶

¹Department of Neurosurgery, Taichung Veterans General Hospital, Taichung, Taiwan

²Department of Orthopedic Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand

³MS DNB FNB Spine, Asha Nursing Home, Pune, India

⁴Dr DY Patil Medical College, Hospital and Research Centre, Dr DY Patil Vidyapeeth, Pune, India

⁵Gloucestershire Hospitals NHS Trust, Gloucestershire, UK

⁶Department of Neurosurgery, Daejeon Woori Hospital, Daejeon, Korea

Corresponding Author: Cheol-Wung Park Department of Neurosurgery, Daejeon Woori Hospital, 70, Munjeong-ro 48beon-gil, Seo-gu, Daejeon 35262, Korea Email: endospine@naver.com

Received December 22, 2024 Accepted February 26, 2025

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study aims to demonstrate the surgical technique of inserting a larger cage, typically used in the oblique lateral interbody fusion (OLIF) approach, through the unilateral biportal endoscopic trans-Kambin triangle lumbar interbody fusion (UBE-KLIF) method to maximize the cage footprint and increase fusion rates with minimal tissue disruption. UBE-KLIF is a minimally invasive alternative to traditional open and other fusion methods, and it is particularly suitable for patients without central spinal stenosis where decompression is unnecessary. In this case, a 68-year-old woman with L4–5 spondylolisthesis and instability, presenting with low back pain radiating to her left lower limb, was treated using the UBE-KLIF approach. A large OLIF cage (50 mm×18 mm×10 mm) was successfully inserted, achieving an endplate-to-cage footprint ratio of 46.8%. The procedure minimized tissue disruption while enabling the use of a larger cage, which could potentially improve the fusion rate. This technique demonstrates the feasibility and effectiveness of inserting a larger OLIF cage via the UBE-KLIF approach in patients without central stenosis, offering a promising minimally invasive option for improving fusion outcomes.

Key Words: Endoscopy, Biportal endoscopic surgery, Lumbar spine, Large cage

WRITTEN TRANSCRIPT

0:00 Topic

Unilateral biportal endoscopic (UBE) trans-Kambin’s triangle lumbar interbody fusion (KLIF), with oblique lateral interbody fusion (OLIF) cage.

0:08 Introduction

Unilateral biportal endoscopy lumbar interbody fusion, a minimally invasive procedure developed as an alternative to traditional open and other minimally invasive fusion methods, is particularly suitable for patients without central stenosis, where central decompression is not required [1].

To increase the fusion rate, expanding the interbody cage footprint plays an important role [2,3].

The cage designed for OLIF surgery, is significantly larger than the transforaminal lumbar interbody fusion cage used in traditional posterior approaches, providing a much broader footprint [4].

This article aims to explore the feasibility of inserting an OLIF cage using the UBE approach [5].

0:45 Case Presentation

A 68-year-old female with a medical history of hypertension, diabetes, and hyperlipidemia presents with a 3-month history of left-sided low back pain, rated 7 out of 10 on the visual analogue scale. The pain radiates to the left lower limb, also rated at 7. She reports that the pain worsens with standing and movement.

1:05 Image Studies

The preoperative dynamic x-rays of the lumbar spine showed L4–5 spondylolisthesis and instability (Figure 1). Magnetic resonance imaging of the lumbar spine revealed a grade one spondylolisthesis at the L4–5 level (Figure 2). Axial views showed no evidence of central spinal stenosis.

1:22 Anesthesia, Patient Positioning

The surgery is performed under general anesthesia with the patient in the prone position. When using the C-arm fluoroscope for positioning, it is crucial to achieve a true anterior-posterior view. This ensures that the incision and the intervertebral endplate are aligned, facilitating smoother cage insertion.

1:37 Localization and Skin Marking

An incision was made 2 cm lateral to the lateral pedicle line, extending from the L5 transverse process to the upper endplate of the disc space, serving as a 2-cm working portal. Additionally, along the lateral pedicle line approximately 2 cm superior to the working portal, a 1-cm incision was made to serve as the scope portal.

1:56 Approach

Step 1, use finger dissection to bluntly separate the muscle tissue over the facet. Step 2, triangulation was performed on the L5 transverse process, and a radiofrequency probe was used to expose the bony structures of the lateral facet and transverse process. Next, the facet joint was exposed to distinguish between the inferior and superior articular processes. Then dissect along the base of superior articular process with radiofrequency probe.

2:27 Remove Superior Articular Process

Locate the neck of the superior articular process. From this point, a high-speed burr was used to grind medially until nearly reaching the spinal canal. Using a Kerrison punch or an osteotome to break the neck of the superior articular process, freeing its tip. The superior articular process was removed in one piece to be used as a bone graft. Confirm the medial wall of the pedicle with a hook. Resect the remaining tip of the superior articular process.

3:00 Remove Partial Inferior Articular Process

Next, to create space for cage insertion, we used a high-speed drill to remove an appropriate portion of the inferior articular process. After completing all the bony work, remove the foraminal ligamentum flavum. Following appropriate hemostasis, the lateral edge of the dura and the exiting root were exposed. Use an radio frequency probe to expose the Kambin triangle. Dissect the soft tissue between the 2 nerves to mobilize them, thereby enlarging the space within the Kambin triangle.

3:29 Annulotomy and Discectomy

Perform annulotomy from the lateral side toward the medial side. Perform the discectomy, use an endplate separator to carefully separate the cartilage endplate from the bony endplate in one piece.

3:45 Insert Cage Trail

Insert the OLIF cage trial through the working portal. Use the Hopper cannula attached to the endoscope to inspect the dura sac and the exiting root. Ensuring the trial does not impinge on or injure the nerves.

4:08 Insert Cage

After testing the trial and selecting the appropriate size, insert the OLIF cage along with the cage slide. Once inserted, recheck to ensure the cage is not impinging on or injuring the nerves on both the medial and lateral sides.

4:42 Tilt the Cage Down

Now, begin the process of laying down the cage into its final position. Use a flat or angled impactor to gently tap the posterior end of the cage, applying torque to gradually lay it transverse in its final position (Figure 3).

Unilateral Biportal Endoscopic Trans-Kambin Triangle Lumbar Interbody Fusion With an Oblique Lateral Interbody Fusion Cage

Abstract

WRITTEN TRANSCRIPT

0:00 Topic

0:08 Introduction

0:45 Case Presentation

1:05 Image Studies

1:22 Anesthesia, Patient Positioning

1:37 Localization and Skin Marking

1:56 Approach

2:27 Remove Superior Articular Process

3:00 Remove Partial Inferior Articular Process

3:29 Annulotomy and Discectomy

3:45 Insert Cage Trail

4:08 Insert Cage

4:42 Tilt the Cage Down

NOTES

Figure 1.

Figure 2.

Figure 3.

REFERENCES