Review History
Assessment of complications and success rates of Percutaneous nephrolithotomy: single tract vs. multi tract approaches

Behzad Narouie · Sep 27, 2024

Additional comments

Accepted for publication .

Reviewer 3 · Sep 29, 2024

Tanan Bejrananda · Oct 1, 2024

Additional comments

Below is a structured review of the manuscript titled "Assessment of complications and success rates of Percutaneous nephrolithotomy: Single tract vs. Multi-tract approaches":

### **1. Basic Reporting**
- **Language**: The manuscript is generally well-written, but a few sections would benefit from improved clarity and grammatical corrections. Examples include:
- Line 24: "ûuoroscopy" should be corrected to "fluoroscopy."
- Line 32: Consider revising "diûerences" to "differences."
- Throughout the text, "multi-tract" and "multi-channel" are used interchangeably. Consistency in terminology would improve clarity.
- **Introduction and Background**: The introduction provides adequate context about the challenges of treating complex and staghorn kidney stones. However, adding recent publications and more detailed comparisons of single-tract versus multi-tract PNL from the literature would strengthen the background and show why this study is needed.
- **Figures and Tables**:
- Figures are clear and relevant but could benefit from higher resolution. For example, Table 1’s presentation could be enhanced by aligning the parameters and formatting values for better readability.
- Table 2 includes valuable information about the outcomes but could be improved by summarizing key trends in a concluding note.

### **2. Experimental Design**
- **Research Scope and Questions**: The research question is well defined, addressing a relevant and meaningful issue in urology. The need for understanding the difference in complications between single and multi-tract approaches is clearly justified.
- **Methods and Replicability**:
- The methods are adequately described, and replication seems possible based on the details provided. However, it would be beneficial to elaborate more on the rationale for excluding specific patients, such as those with kidney abnormalities or skeletal deformities. Were there any other considerations that might affect generalizability?
- The criteria for defining success (i.e., "stone-free" status as stones <4 mm) is reasonable, but it could be beneficial to discuss why 4 mm was used as the threshold, as standards may vary.
- **Ethical Considerations**: Ethical approval and consent are well documented. However, there is no mention of any potential biases due to the retrospective nature of the data.

### **3. Validity of the Findings**
- **Data and Analysis**:
- The study includes robust data on 208 patients, split into two groups based on single-tract and multi-tract PNL. The statistical analyses used are appropriate, but the sample sizes of the groups are unequal. It would be beneficial to comment on any potential biases or statistical limitations due to the smaller size of the multi-tract group.
- The study reports a statistically significant difference in fluoroscopy and operation times between groups, but the clinical relevance of these differences should be more explicitly discussed. For example, how do longer operation times affect patient outcomes or recovery?
- **Interpretation of Results**:
- The authors conclude that multi-tract PNL is feasible, though it has slightly higher complications. However, the practical implications of these complications are not adequately explored. For instance, while the drop in hemoglobin is noted, how does this impact post-operative care, patient discomfort, or follow-up protocols?
- The comparison of complication rates between single-tract and multi-tract PNL is comprehensive, but there is little discussion on potential preventive measures for complications in the multi-tract group.

### **4. General Comments**
- **Strengths**:
- The manuscript addresses an important gap in the literature regarding the safety and efficacy of multi-tract versus single-tract PNL.
- It uses clearly defined metrics to compare both groups and adheres to established classification systems (e.g., Clavien-Dindo for complications).
- **Weaknesses**:
- The study is limited by its retrospective nature. The authors should elaborate on potential biases or limitations stemming from this, and perhaps suggest how these could be addressed in future research.
- The use of a single surgeon for all operations is a double-edged sword—it controls for variability, but may limit the generalizability of findings to other surgeons with different experience levels. Discussing how generalizable the results are to other settings would be helpful.
- **Suggestions for Improvement**:
- Consider adding a paragraph in the **Discussion** about the clinical implications of the findings, such as how these findings might change practice in terms of choosing single vs. multi-tract PNL based on patient characteristics or stone burden.
- Provide more detail on how patients were followed postoperatively, especially those with complications. For instance, what kind of interventions or additional care was needed for patients with major complications?
- Discuss whether the findings align with or contradict recent literature, particularly regarding transfusion rates and hemoglobin drop. This will help place the findings in a broader clinical context.
- Address the limitations more explicitly, particularly the impact of the retrospective design and the single-center nature of the study on the generalizability of results.

### **5. Confidential Notes to the Editor**
- The manuscript is generally well-prepared, and the topic is relevant to urologists managing complex kidney stones. The retrospective nature is a limitation that the authors acknowledge, but they should be encouraged to emphasize this limitation in the manuscript. It would also be beneficial to ask for a more detailed comparison of their findings with those in the existing literature.
- The sample size disparity between the groups is a potential limitation that could affect the statistical power and should be addressed in greater depth by the authors.
- The figures and tables are acceptable, but improvements in formatting and resolution would enhance the overall presentation of the data.

Overall, this study adds valuable information about the safety and efficacy of multi-tract PNL. The authors should refine certain sections, such as the methods and discussion, to improve the readability and context of the study findings.

Behzad Narouie · Apr 19, 2024

Reviewer 2 · Jun 1, 2024

Reviewer 3 · Jul 14, 2024

Tanan Bejrananda · Jul 22, 2024

Additional comments

Here's a detailed review of your manuscript, with comments for improvement in each section:

### Title and Author Information

**Title**:
- Consider rephrasing for clarity and conciseness. Example: "Comparative Assessment of Complications and Success Rates in Percutaneous Nephrolithotomy: Single Tract vs. Multi-Tract Access."

**Author Information**:
- Ensure consistent formatting of author names and affiliations.
- Double-check the contact details for accuracy.

### Abstract

**Purpose**:
- The objective is clear. No significant issues here.

**Material and Methods**:
- Provide a brief explanation of what PNL is, as not all readers may be familiar with it.

**Results**:
- The results are detailed but could be more concise. Focus on the most significant findings.

**Conclusion**:
- The conclusion is clear and well-structured.

### Introduction

- **First Paragraph**:
- Consider mentioning why staghorn or complex calyceal stones are particularly challenging.
- Include a brief overview of other treatment methods and why PNL is preferred.

- **Second Paragraph**:
- This paragraph is well-written, providing the rationale for the study.
- Expand slightly on the potential complications associated with multiple tracts to set up the study's significance.

- **Third Paragraph**:
- This is redundant as it repeats information from the abstract. Consider integrating it into the introduction more smoothly.

### Materials and Methods

- **Study Design**:
- Clearly state the study's retrospective nature.
- Mention the ethical approval earlier in this section to reassure readers about the study's integrity.

- **Participants**:
- Specify the inclusion and exclusion criteria more clearly. Consider bullet points for better readability.

- **Surgical Procedure**:
- The description is detailed, but could be more concise. Focus on key steps and differences between single and multi-tract approaches.

- **Statistical Analysis**:
- Clearly explain why certain statistical tests were chosen.
- Ensure all statistical methods are appropriately justified and referenced.

### Results

- **Demographic Data**:
- Presenting in table format is good. Ensure all relevant demographic data are included and clearly labeled.

- **Operation and Fluoroscopy Time**:
- The comparison is clear, but ensure the statistical significance is highlighted.

- **Hemoglobin Levels and Transfusion Rates**:
- Discuss the clinical relevance of the hemoglobin drop in more detail.

- **Stone-Free Rates and Complications**:
- Clearly differentiate between minor and major complications.

### Discussion

- **First Paragraph**:
- This provides a good summary of the study's findings. Ensure you reference other key studies here.

- **Stone-Free Rates**:
- The discussion on stone-free rates is solid. Compare your findings with those from other significant studies.

- **Complications**:
- Discuss the potential reasons for the differences in complication rates more deeply.
- Mention any limitations in measuring complications or variations in surgical technique.

- **Clinical Relevance**:
- Clearly state how your findings can impact clinical practice.

### Conclusion

- **Key Findings**:
- Summarize the main findings concisely. Avoid repeating the results in detail.

- **Recommendations**:
- Provide clear recommendations for clinical practice based on your findings.

### References

- Ensure all references are up-to-date and relevant.
- Verify that all citations are correctly formatted according to the journal's guidelines.

### General Comments

- **Formatting**: Ensure consistent formatting throughout the manuscript. Use the same font and size for all sections.
- **Language**: Proofread for grammatical errors and typos. Consider professional editing for clarity and fluency.
- **Figures and Tables**: Make sure all figures and tables are clearly labeled and referenced in the text.

In summary, the manuscript is well-structured and provides valuable insights into PNL. By addressing these comments, you can enhance the clarity and impact of your study before publication.