High Fusion Rates with Structured Titanium TLIF Cages: A Retrospective 1-Year Study with and Without Adjacent Level Dynamic Stabilization

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. The study presents a retrospective analysis of patient outcomes following TLIF with structured titanium cages, comparing those with and without adjacent-level dynamic stabilization. While the study reports high fusion rates and significant improvements in patient-reported outcomes (PROMs), the manuscript would benefit from a more detailed discussion on the potential confounding factors that may have influenced the results. For instance, the authors should address the baseline characteristics of the two groups, including age, gender, BMI, preoperative diagnosis, and the severity of the spinal pathology, which could have an impact on the fusion rates and clinical outcomes. Additionally, the manuscript should include a more comprehensive analysis of the complications and reoperation rates, as these are critical for evaluating the overall safety and efficacy of the surgical interventions.
2. The manuscript reports that the addition of dynamic stabilization had no significant effect on PROM or fusion outcomes at 12 months. However, the long-term effects of dynamic stabilization on adjacent segment disease have not been fully elucidated in this study. The authors should provide a more nuanced interpretation of these findings given the relatively short follow-up period of 12 months. It is important to acknowledge the limitations of short-term studies in predicting long-term outcomes, especially in the context of spinal surgery where delayed complications may occur. The manuscript should also discuss the rationale for the use of dynamic stabilization in the hybrid instrumentation group and whether there are specific indications or patient subgroups that may benefit more from this approach. Future studies with longer follow-up are recommended to better understand the role of dynamic stabilization in preventing adjacent segment disease.

Author Response

Comment 1: The manuscript would benefit from a more detailed discussion on potential confounding factors such as baseline characteristics.

Response: We have added a dedicated paragraph to the Discussion section explicitly addressing potential confounders, including differences in age, surgical indications (e.g., radiculopathy vs. claudication), and surgical history (primary vs. revision). These factors may have influenced outcomes and are now discussed as limitations of the retrospective study design.

 

Comment 2: The manuscript should include a more comprehensive analysis of complications and reoperation rates.

Response: Complication and reoperation data are now discussed in more depth in the Discussion section, including superficial infections and the low overall reoperation rate (4.8%). This additional analysis supports the safety profile of both surgical techniques.

 

Comment 3: The 12-month follow-up may be insufficient to assess long-term effects of dynamic stabilization.

Response: We agree and have expanded the limitations paragraph to emphasize that long-term outcomes, particularly regarding adjacent segment disease (ASD), require further study. We clarify that our focus was short-term efficacy and safety.

 

Comment 4: Discuss rationale for DSS use and possible patient subgroups that may benefit.

Response: We have revised the Discussion to include the rationale for DSS usage, particularly in older patients or those with adjacent-level symptoms. We now mention that DSS was used based on surgeon preference and clinical indications of early adjacent-level degeneration or mobility concerns

Reviewer 2 Report

Comments and Suggestions for Authors

This is a well writen paper with a proper methodological design related to TLIF cages. I have some minor recommendations for the authors:

1. remove abbreviations from the abstract keywords section
2. include the flowchart in the methods section, rather than results section
3. what were the way of assessing fusion rates? was there any procedure? Please detail in section 2.3.
4. Figure 3 graphs are too small. Consider replacing them with higher resolution images
5. All the sections are adequately presented, and the results are clear
6. References are relevant to the cited work
7. The abbreviations list is missing some of the terms used

Author Response

Comment 1: Remove abbreviations from the abstract keyword section.

Response: Abbreviations have been removed from the keyword list and replaced with full terminology (e.g., “Transforaminal Lumbar Interbody Fusion” instead of “TLIF”).

 

Comment 2: Include the patient flowchart in the Methods section.

Response: The flowchart (Figure 2) has been moved to the Methods section (now Section 2.2) and referenced appropriately.

 

Comment 3: Clarify fusion assessment method.

Response: Section 2.3 has been expanded to include details of the fusion assessment procedure. Specifically, we now state that fusion was evaluated via thin-slice sagittal and coronal CT scans by two independent reviewers (a radiologist and a spine surgeon) using criteria such as continuous trabecular bridging bone across the disc space.

 

Comment 4: Figure 3 graphs are too small.

Response: We have replaced Figure 3 with a set of higher-resolution plots that clearly distinguish between groups and outcomes across timepoints. These plots are now optimized for clarity and legibility.

 

Comment 5: Some abbreviations used in the text are missing from the abbreviation list.

Response: We have reviewed the manuscript for abbreviation consistency and updated the list to include missing items such as PROMs, DSS, EQ-5D-5L, and ODI.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

It would be helpful to include any recent studies published since the literature search cut-off date to ensure that the discussion is up-to-date.

Author Response

Review Question	Reviewer’s Evaluation	Author Response
Does the introduction provide sufficient background and include all relevant references?	Can be improved	We have revised the introduction to include multiple recent references published in 2023–2024 related to porous titanium cages, dynamic stabilization, and topping-off techniques. This ensures the background is up-to-date and more comprehensive. (See page 2, paragraph 3.)
Is the research design appropriate?	Can be improved	We kindly invite the reviewer to clarify whether there are any specific areas where further improvement is recommended.
Are the methods adequately described?	Can be improved	We kindly invite the reviewer to clarify whether there are any specific areas where further improvement is recommended.
Are the results clearly presented?	Can be improved	We kindly invite the reviewer to clarify whether there are any specific areas where further improvement is recommended.
Are the conclusions supported by the results?	Can be improved	We kindly invite the reviewer to clarify whether there are any specific areas where further improvement is recommended.
Are all figures and tables clear and well-presented?	Can be improved	We kindly invite the reviewer to clarify whether there are any specific areas where further improvement is recommended.

Author Response File: Author Response.docx