Unilateral biportal endoscopy (UBE)

Dr Huang Yilun

Dr Huang Yilun is an experienced Orthopaedic Consultant and Spine Surgeon with over 15 years of expertise in managing complex spinal conditions. Specialising in endoscopic spine surgery and joint preservation, he trained under renowned mentors in Korea and France, and now serves as the Lead of the Endoscopic Spine Surgery Focus Group within the Singapore Spine Society.

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Table of Contents

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What is Unilateral Biportal Endoscopy ?

Unilateral biportal endoscopy (often shortened to UBE or biportal endoscopic spine surgery) is a minimally invasive spine technique that uses two separate working channels (portals) through a single side of the back: one for the endoscope (visualization) and one for instruments (working). Continuous fluid irrigation maintains a clear field while the spine doctor performs decompression or discectomy using standard microsurgical tools adapted to the endoscopic environment. 

How UBE differs from other endoscopic or “MIS” approaches:

Two portals vs Unilateral Biportal Endoscopyone

Unlike uniportal full-endoscopic systems (one channel for both seeing and working), UBE separates vision and instrumentation. This separation can improve instrument maneuverability and visualization in tight spaces.

Use of conventional instruments

Surgeons can use familiar microsurgical tools through the working portal, which is one reason UBE has been adopted by centers already experienced in microsurgery.

Irrigation-based visualization

UBE typically relies on continuous saline irrigation to clear blood and debris, a feature that affects both visibility and fluid management considerations.

Typical Conditions where Unilateral Biportal Endoscopy may be considered:

UBE is most frequently used for degenerative lumbar conditions, including:

Lumbar disc herniation

(central, paracentral, some far-lateral cases with appropriate approach selection).

Lumbar spinal canal stenosis

(central, lateral recess), including selected bilateral decompressions via a unilateral approach.

Foraminal stenosis and adjacent segment disease

in carefully chosen patients.

As with any technique, patient selection is critical and determined by the treating spine surgeon after correlating symptoms with imaging and exam findings. (This overview is informational and not medical advice.)

What happens during the operation (high-level steps):

Positioning & imaging

The patient is positioned prone; intraoperative fluoroscopy is used to plan the skin entry points and confirm levels.

Two portals on one side

Small incisions are made on the symptomatic side to create a viewing portal for the endoscope and a working portal for instruments.

Decompression or discectomy

Under continuous irrigation, the surgeon decompresses the nerve structures (e.g., partial laminotomy/medial facetectomy, ligamentum flavum removal) and/or removes herniated disc fragments, depending on indication.

Hemostasis & closure

Bleeding control is achieved endoscopically; portals are closed in layers.

Clinical Outcomes ofUnilateral Biportal Endoscopy:

Comparable clinical results to standard techniques

Multiple comparative studies and reviews report that, for properly selected lumbar cases, UBE can achieve pain relief and functional improvement comparable to microscopic lumbar decompression or microdiscectomy.

Peri-operative metrics

Several analyses note trends such as lower rates of blood loss and shorter length of hospitalization with UBE relative to some open or microscope-assisted approaches, while operative times can be similar or sometimes longer, especially early in adoption. These findings vary by study design and surgeon experience.

Risks and potential complications of Unilateral Biportal Endoscopy:

Reported complications with UBE largely overlap with other lumbar decompression/discectomy procedures, and include:

Dural tear

(with possible CSF leak), sometimes associated with postoperative headache.

Transient dysesthesia/paresthesia

or nerve root irritation, epidural hematoma, infection, and inadequate decompression (occasionally requiring revision).

Fluid-related considerations

Because UBE uses continuous irrigation, meticulous fluid management and awareness of pressure effects are important to minimize irrigation-related issues.

Overall complication profiles in contemporary series are generally low and comparable to other minimally invasive decompression techniques, but rates vary with indication, technique, and experience.

When Unilateral Biportal Endoscopy may not be suitable:

Unilateral Biportal Endoscopy may not be suitable for individuals experiencing:

Fixed or high-grade instability

that may require fusion rather than decompression alone.

Severe deformity

large multilevel disease, or pathology not amenable to an endoscopic corridor, where other approaches may be more appropriate at the surgeon’s discretion. (General principle reflected across technique reviews.)

UBE vs. uniportal endoscopy vs. microscopic “MIS” surgery (context)

UBE vs uniportal endoscopy

UBE’s separate viewing/working portals can offer greater instrument freedom; uniportal systems can be more compact but may limit instrument angles. Choice depends on surgeon training and case needs.

UBE vs microscopic MIS (tubular) approaches

Studies comparing UBE with tubular microdiscectomy show similar clinical improvements, with differing trade-offs in operative time, analgesic consumption, and peri-operative metrics across series.

Post-operative course and recovery after Unilateral Biportal Endoscopy:

Recovery after Unilateral Biportal Endoscopy (UBE) varies from person to person and depends on the underlying condition, extent of nerve compression, and overall health. Many patients are encouraged to begin gentle walking soon after surgery, as movement can help maintain circulation and support early mobility.

Mild discomfort, muscle soreness, or temporary numbness may be experienced around the surgical sites as tissues heal. Pain medication and wound-care instructions will be provided. Patients are usually advised to avoid heavy lifting, prolonged bending, and strenuous activities during the initial healing phase.

A gradual return to daily routines and light activity is typically expected, with physiotherapy often recommended to improve core strength, posture, and spinal stability. Most individuals resume normal activities as comfort allows, under the guidance of their surgeon. Follow-up appointments are scheduled to monitor recovery and ensure that the nerves have adequate relief.

If new or worsening symptoms occur (such as increasing pain, weakness, or wound concerns), prompt medical review is recommended.

In summary:

Frequently Asked Questions

Is Unilateral biportal endoscopy considered “minimally invasive”?

Yes. Unilateral biportal endoscopy is classified as a minimally invasive technique due to limited muscle dissection and bone removal.

Unilateral biportal endoscopy usually does not require implants for decompression alone. If instability is identified, a fusion procedure might be recommended instead.

Yes, in specific cases, Unilateral biportal endoscopy allows bilateral decompression via a unilateral approach.

Most unilateral biportal endoscopy procedures are performed under general anesthesia according to current literature.

Unilateral biportal endoscopy varies based on individual patient pathology and surgeon experience.

Unilateral biportal endoscopy is primarily used to treat conditions in the lumbar spine. Expanding interest exists in:

  • Cervical biportal approaches
  • Thoracic endoscopic decompression

Still evolving and less established than lumbar use.

Recovery from Unilateral biportal endoscopy depends on patient factors, extent of pathology, and surgeon protocol. Many people return to light activities relatively soon after decompression surgery.

Complication rates in studies are generally comparable to other minimally invasive decompression techniques when performed by experienced surgeons and in suitable cases.