Impact of the S–O Clip on Endoscopic Submucosal Dissection Outcomes: A Meta-Analysis

The meta-analysis on the impact of the S–O clip on Endoscopic Submucosal Dissection (ESD) outcomes provides compelling evidence supporting the clinical benefits of this traction device. Below is a detailed summary of the findings:

### **Background and Challenges in ESD**

Endoscopic submucosal dissection (ESD) is a highly effective technique for removing early gastrointestinal (GI) neoplasms with en-bloc resection. However, it is technically demanding and associated with challenges such as:

1. **Poor submucosal visibility** during dissection.

2. **Long procedure times**, increasing operator fatigue and potential complications.

3. **Risk of complications** such as bleeding and perforation.

To address these limitations, traction devices like the S–O clip have been developed to improve procedural efficiency and safety.

### **Role and Mechanism of the S–O Clip**

The S–O clip is a specialized traction device designed to enhance submucosal exposure during ESD. Its **spring-and-loop mechanism** provides stable counter-traction, enabling better visibility of submucosal layers and facilitating precise dissection. Importantly, the design minimizes obstruction of the endoscopic field, allowing for uninterrupted visualization and manipulation.

### **Meta-Analysis Design**

This meta-analysis followed the **PRISMA guidelines** and synthesized evidence from 17 studies involving 1,449 patients. The included studies compared ESD outcomes with and without S–O clip assistance, focusing on procedure efficiency, safety, and resection quality.

### **Key Findings**

#### **1. Procedure Time Reduction**

The use of the S–O clip significantly shortened ESD procedure times compared to conventional techniques. This is attributed to improved submucosal exposure, which allows for faster and more precise dissection. The reduction in procedure time may also decrease operator fatigue, enhancing technical precision and overall safety.

#### **2. Improved Dissection Speed**

Dissection speed was consistently higher with S–O clip assistance across studies. This reflects the device's ability to provide stable traction and optimize the efficiency of submucosal dissection.

#### **3. Higher En-bloc Resection Rates**

The S–O clip modestly but significantly increased **en-bloc resection rates**, which is critical for achieving complete removal of neoplastic tissue and minimizing recurrence risk. This advantage was particularly evident in colorectal ESD.

#### **4. Comparable Complete Resection (R0) Rates**

Complete resection rates (R0) were similar between S–O clip-assisted and conventional ESD groups, indicating that the device does not compromise the quality of resection.

#### **5. Maintained Safety Profile**

No significant increase in intraoperative perforation rates was observed with S–O clip use, demonstrating its safety during ESD. Additionally, post-ESD bleeding rates were comparable between S–O clip-assisted and conventional techniques.

#### **6. Lesion-Specific Benefits**

• **Gastric Lesions**: The S–O clip significantly reduced procedure time and improved dissection speed for gastric neoplasms.
• **Colorectal Lesions**: In colorectal ESD, the device resulted in higher en-bloc resection rates and faster dissection.
• **Duodenal Lesions**: Evidence for duodenal lesions was limited, though procedure time appeared reduced with S–O clip use.

### **Additional Advantages**

#### **1. Reduced Operator Fatigue**

Shorter procedure times with the S–O clip may alleviate operator fatigue, which is particularly important for lengthy and complex ESD cases. Reduced fatigue can improve technical precision and minimize the risk of errors.

#### **2. Training Implications**

The S–O clip may facilitate safer and more efficient ESD performance by less experienced endoscopists. Its ability to enhance submucosal exposure and simplify dissection may serve as a valuable training tool.

#### **3. Cost-Effectiveness**

While the S–O clip adds to procedural costs, its ability to reduce procedure time and complications may offset device expenses, particularly in high-volume centers.

### **Evidence Quality**

The majority of included studies were assessed as **low risk of bias**, with moderate-to-high certainty of evidence for key outcomes such as procedure time, dissection speed, and en-bloc resection rates.

### **Clinical Recommendations**

Based on the meta-analysis findings, the S–O clip is a valuable adjunct for ESD, particularly for gastric and colorectal lesions. It improves procedural efficiency without compromising safety or resection quality. While evidence for duodenal lesions is limited, preliminary data suggest potential benefits. The device is recommended for routine use in ESD, especially in high-volume centers and training programs.

### **Conclusion**

The S–O clip significantly enhances ESD outcomes by improving submucosal visibility, reducing procedure time, increasing dissection speed, and modestly improving en-bloc resection rates. Its safety profile is comparable to conventional techniques, with no increased risk of perforation or bleeding. These findings support the widespread adoption of the S–O clip as a valuable tool for optimizing ESD performance.