For millions suffering from chronic back and leg pain due to lumbar degenerative disease, the prospect of spine surgery can be daunting. Traditional open surgery, while effective, often involves a long and painful recovery. The rise of minimally invasive endoscopic spine surgery has been a game-changer, allowing surgeons to perform major decompressions and fusions through tiny incisions. But within this advanced field, a new debate has emerged: is the two-portal (biportal) endoscopic technique superior to the single-portal (uniportal) approach? This article dives into the latest scientific evidence to uncover which technique might be best for patients.
The Key Players: Understanding the Techniques
Before comparing the techniques, it's essential to understand what they are. Both uniportal and biportal endoscopy aim to treat common issues like lumbar disc herniations and spinal stenosis with minimal tissue damage.
Uniportal Endoscopy (UPFE)
This is the epitome of minimalism. The surgeon makes a single small incision through which a specialized endoscope is inserted. This device contains both a camera for visualization and a channel for surgical instruments.
Advantage: Highly streamlined approach
Challenge: The confined space can limit instrument movement and make controlling bleeding more challenging 7
Biportal Endoscopy (UBE)
As the name suggests, this technique uses two separate small incisions (portals) placed about 2-3 cm apart. One portal is dedicated to the endoscope for a clear, magnified view, while the other is used for a full range of surgical instruments.
Visual Comparison of Surgical Approaches
Uniportal (Single Portal)
One incision for both visualization and instruments
Biportal (Dual Portals)
Separate portals for visualization and instruments
The Verdict from Evidence: A Close Look at the Data
So, how do these techniques stack up against each other in practice? Multiple meta-analyses—which statistically combine results from several studies to provide more powerful conclusions—have sought to answer this question. The findings reveal a nuanced picture where each technique has its own strengths.
| Outcome Measure | Uniportal (UPFE) Advantage | Biportal (UBE) Advantage | No Significant Difference |
|---|---|---|---|
| Operative Time | Shorter for simple disc herniations 1 | Shorter for complex procedures like fusions 5 | Varies by specific procedure |
| Intraoperative Blood Loss | Less blood loss 1 | ||
| Hospital Stay | Shorter stay 1 | ||
| Early Post-Op Back Pain | Better pain relief in first few days 2 7 | ||
| Postoperative Dural Expansion | Greater increase in canal area 1 | ||
| Long-Term Pain & Function | ODI and VAS scores at 3+ months 1 2 | ||
| Complication Rates | Overall safety profile 1 2 |
Uniportal Advantages
- Faster surgery for simple cases
- Less blood loss
- Shorter hospital stay
- Less early postoperative pain
Biportal Advantages
- Better for complex procedures
- Greater surgical freedom
- Superior canal expansion
- Two-handed technique
A Deeper Dive into a Key Study
To truly understand how these conclusions are reached, let's examine a specific 2024 meta-analysis published in the Journal of Orthopaedic Science 1 . This study provides a robust model of how such research is conducted.
2024 Meta-Analysis Methodology
Literature Search
The researchers systematically combed through seven major scientific databases to find all relevant studies published up to March 2022.
Study Selection
They applied strict inclusion and exclusion criteria to ensure only high-quality, comparable studies were analyzed.
Data Analysis
In the end, nine articles were selected for the final quantitative analysis.
Statistical Methods
For each study, data on critical outcomes were extracted and statistical models were used to calculate collective effect sizes.
Key Finding
UBE demonstrated a clear advantage in one crucial area: it achieved a greater increase in the postoperative dural sac area 1 .
This means the UBE technique may create more free space for the compressed nerves, a potentially important factor for patients with severe spinal stenosis.
| Outcome | Mean Difference (MD) / Odds Ratio (OR) | Confidence Interval (CI) | Significance |
|---|---|---|---|
| Operative Time | MD: 17.14 minutes | 6.52 to 27.76 | Favors UPFE |
| Intraoperative Bleeding | MD: 59.01 mL | 21.29 to 96.73 | Favors UPFE |
| Hospital Stay | MD: 2.12 days | 0.35 to 3.90 | Favors UPFE |
| Complication Rate | OR: 0.82 | 0.31 to 2.12 | Not Significant |
The Surgeon's Toolkit: Essentials of Endoscopic Spine Surgery
Performing delicate surgery through a keyhole requires a specialized set of tools and a deep understanding of the surgical environment. The following "toolkit" is critical for success in both uniportal and biportal procedures.
High-Definition Endoscope
Provides a magnified, clear view of the intricate spinal anatomy on a monitor. The foundation of the entire procedure 7 .
Continuous Saline Irrigation
Fluid flow (usually gravity-fed) clears the field of blood and debris. Proper "inflow and outflow" is critical for maintaining a clear view .
Specialized Instruments
Miniaturized burrs (drills), Kerrison rongeurs (for bone removal), and nerve hooks designed to operate in tight spaces 9 .
Fluoroscopy (C-arm)
Real-time X-ray used at the start of surgery to accurately locate the spinal level and guide initial instrument placement .
Triangulation
A key concept in biportal endoscopy where the surgeon mentally converges the separate paths of the endoscope and instrument at the target point .
Hemostatic Tools
Bipolar radiofrequency probes are used to control bleeding, essential for preventing the "red screen" phenomenon that can obscure vision .
The Future is Complementary, Not Competitive
Tailored Approach for Optimal Outcomes
Rather than a clear winner, the evidence suggests that uniportal and biportal endoscopic techniques are largely complementary 7 . Mastery of both allows a surgeon to tailor the operation to the patient's specific needs.
Choose Uniportal for:
Contained disc herniations, especially at the L5-S1 level, and when the goal is the absolute minimal tissue disruption and fastest early recovery 7 .
Complementary Techniques
The future of spine surgery lies in this kind of tailored, patient-specific approach. As one editorial puts it, "Dual proficiency allows the surgeon to tailor an approach to the specific anatomical and pathological context, widening the scope of cases amenable to endoscopic intervention" 7 . The focus is shifting from which technique is better in general to which technique is better for you.
Further Reading
If you want to learn more about the practical steps surgeons take when learning these techniques, you can refer to the 10 essential starting points for biportal endoscopy outlined by spine surgeons .