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Unilateral Biportal Endoscopy (UBE) versus Percutaneous Endoscopic Lumbar Discectomy (PELD) for Lumbar Disc Herniation: Comparative Outcomes, Complication Risk Factors, and Predictive Model

This retrospective study compares Unilateral Biportal Endoscopy (UBE) and Percutaneous Endoscopic Lumbar Discectomy (PELD) for lumbar disc herniation, finding that while PELD offers faster early recovery, UBE results in lower recurrence rates, and introduces a validated nomogram model to predict postoperative adverse events based on identified risk factors to guide individualized surgical selection.

Original authors: Shuai Zhao¹, Jibin Wu¹, Ming Zhang

Published 2026-07-28

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CC BY 4.0

Original authors: Shuai Zhao¹, Jibin Wu¹, Ming Zhang

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine your spine as a towering stack of jelly-filled donuts, each one cushioning the bones above and below. Sometimes, the jelly inside a donut squirts out the side, pressing on the nerves that run down your legs. This is called a lumbar disc herniation, and it can turn a simple walk into a painful ordeal. For decades, the solution was a big surgery with a large cut, but doctors have been on a quest to find "keyhole" solutions—tiny, precise ways to fix the problem without wrecking the surrounding muscles. Two of the most popular "keyhole" tools are PELD and UBE. Think of PELD as a single, narrow straw you stick through a tiny hole to suck out the jelly; it's fast and leaves a tiny mark. UBE, on the other hand, is like using two small holes: one for a camera to see clearly, and another for a tool to grab the jelly. It gives the surgeon a wider view, like having a second hand to help, but it takes a bit more time to set up. The big question for doctors and patients is: which tool is better? Is the speed of the straw worth the risk of leaving some jelly behind, or is the extra time and effort of the two-hole method worth it for a cleaner fix?

This study, conducted by researchers at The Affiliated Hospital of Xuzhou Medical University, decided to put these two tools to the test. They looked back at the records of 216 patients who had a single-level disc herniation and were treated with either the single-straw method (PELD) or the two-hole method (UBE) between January 2020 and December 2024. The team wanted to see not just who felt better, but who had more trouble after surgery, like the pain coming back or unexpected complications.

The results painted a clear picture of trade-offs. If you are looking for the fastest recovery right out of the gate, the PELD group had the edge. These patients lost less blood during the surgery, stayed in the hospital for a shorter time, and reported less back pain in the very early days after the operation. However, the UBE group had a major advantage in the long run: their herniation was much less likely to come back. The study found that the recurrence rate (the chance of the problem returning) was only 2.8% for the UBE group, compared to 9.2% for the PELD group. While both groups ended up feeling similarly good after a full year, the UBE method seemed to do a more thorough job of cleaning out the problem area.

But the researchers didn't stop at just comparing the tools; they wanted to know who was most likely to have a bad outcome, regardless of which tool was used. They built a special "risk calculator" (called a nomogram) to help doctors predict trouble before the surgery even starts. They discovered that five specific things made a patient more likely to face complications or a return of the pain: being 65 years or older, having a Body Mass Index (BMI) of 28 kg/m² or higher, having specific changes in the bone called "Modic II changes," having a type of herniation where the jelly has broken free (non-contained), and, interestingly, choosing the PELD procedure itself.

The study concludes that both methods are safe and effective, but they serve different needs. If a patient is young, not overweight, and has a contained herniation, the quick and easy PELD might be the best bet for a speedy recovery. However, for older patients, those with higher BMIs, or those with complex, broken-free herniations, the UBE method is suggested as the safer choice to avoid the herniation coming back. The new risk calculator the team built can help surgeons look at a patient's specific details and pick the right tool, ensuring that the choice of surgery is as personalized as the patient's own body.

Technical Summary: Unilateral Biportal Endoscopy (UBE) versus Percutaneous Endoscopic Lumbar Discectomy (PELD) for Lumbar Disc Herniation

Problem Statement
Lumbar disc herniation (LDH) is a prevalent musculoskeletal disorder significantly impacting quality of life. While Unilateral Biportal Endoscopy (UBE) and Percutaneous Endoscopic Lumbar Discectomy (PELD) are established minimally invasive surgical options, existing comparative literature primarily focuses on general clinical efficacy metrics such as Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI). There is a notable gap in the analysis of postoperative complication and recurrence risk factors, and currently, no predictive models exist to assist surgeons in preoperative decision-making for individualized treatment selection between these two techniques.

Methodology
This study employed a retrospective cohort design involving 216 patients with single-level LDH treated at The Affiliated Hospital of Xuzhou Medical University between January 2020 and December 2024. Patients were divided into two groups: UBE ( $n=107$ ) and PELD ( $n=109$ ).

Surgical Protocols: The UBE group underwent general anesthesia with two 8 mm portals for endoscopic visualization and instrumentation under saline irrigation. The PELD group utilized a single portal via Kambin's triangle under local or general anesthesia.
Data Collection: Perioperative parameters (operation time, blood loss, hospital stay), functional outcomes (VAS back/leg, ODI) at 1, 3, 6, and 12 months, and adverse events (complications and recurrence) were recorded.
Statistical Analysis: Univariate and multivariate logistic regression analyses were conducted to identify independent risk factors for postoperative adverse events (defined as a composite of complications or recurrence). Based on these factors, a nomogram prediction model was constructed and validated using the C-index and calibration curves.

Key Contributions

Comparative Outcomes Analysis: The study provides a direct comparison of perioperative and long-term outcomes, highlighting specific trade-offs between the two techniques.
Risk Factor Identification: It identifies specific independent risk factors associated with postoperative adverse events, moving beyond general efficacy to specific safety and recurrence predictors.
Predictive Modeling: The paper constructs and validates a clinical nomogram model designed to predict the probability of postoperative adverse events, facilitating individualized surgical strategy.

Results

Perioperative Metrics: The UBE group demonstrated significantly longer operation times. Conversely, the PELD group exhibited significantly less intraoperative blood loss, shorter hospital stays, and lower early postoperative back pain VAS scores ( $P < 0.05$ ).
Functional Outcomes: Both groups showed significant improvements in back VAS, leg VAS, and ODI at all follow-up points. At the 12-month mark, there were no significant differences between the groups regarding leg pain relief or ODI improvement.
Complications and Recurrence: The overall complication rates were comparable between groups (UBE: 8.4% vs. PELD: 11.9%; $P > 0.05$ ). However, the recurrence rate was significantly lower in the UBE group compared to the PELD group (2.8% vs. 9.2%; $P = 0.042$ ).
Risk Factors: Multivariate logistic regression identified five independent risk factors for postoperative adverse events:
1. Age $\ge$ 65 years
2. BMI $\ge$ 28 kg/m²
3. Modic II changes
4. Non-contained herniation
5. Undergoing the PELD procedure
Model Performance: The constructed nomogram demonstrated good discrimination with a C-index of 0.826 (95% CI: 0.761–0.891) and excellent calibration between predicted and actual probabilities.

Significance and Claims
The authors assert that both UBE and PELD are safe and effective minimally invasive treatments for single-level LDH. The study concludes that while PELD offers advantages in early postoperative recovery (less blood loss, shorter stay, less early pain), UBE provides a superior long-term outcome regarding lower recurrence rates.

The primary significance of this work lies in the development of the predictive nomogram. The authors claim this is the first model to combine clinical, imaging, and surgical factors to predict adverse events specifically for the UBE versus PELD decision. They suggest that this tool can guide individualized surgical selection: recommending UBE for high-risk patients (e.g., elderly, obese, non-contained herniation) to mitigate recurrence and complications, while favoring PELD for lower-risk patients seeking faster recovery. The authors acknowledge limitations, including the retrospective, single-center nature of the study and the 12-month follow-up period, noting that larger, multicenter prospective studies are required for further validation.

Technical Summary: Unilateral Biportal Endoscopy (UBE) versus Percutaneous Endoscopic Lumbar Discectomy (PELD) for Lumbar Disc Herniation

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