Conducting reliable research: transparency, integrity and disclosing conflicts of interest

It is with great interest that we read the manuscript “Expandable cages that expand both height and lordosis provide improved immediate effect on sagittal alignment and short-term clinical outcomes following minimally invasive transforaminal lumbar interbody fusion (MIS TLIF)” by Jitpakdee et al. (1). In this retrospective study of 149 patients, patients who received a cage that could increase the disc height were compared with cages that could increase both the disc height and the lordosis. Visual analogue scale (VAS) and the Oswestry Disability Index (ODI) were collected as clinical measures while disc height, angle and sagittal alignment were measured as radiological outcomes. The study concluded that expendable cages that can increase both disc height and lordosis can provide favorable outcomes and improve sagittal alignment following MIS TLIF compared to conventional cages. While the study provides interesting data, some issues of this paper warrant discussion.

The most important issue is the unacknowledged conflict of interest of the authors and more specifically the corresponding/senior author. In the medical field, working together with the medical industry is a necessity as this helps the progression of technical and scientific advances in the field. However, it is important for doctors and scientists to disclose these collaborations or other potential conflict of interest so that readers but also peer-reviewers can cautiously interpret the study. In this study the authors fail to disclose the conflict of interest.

In this study both the cages (SABLE^® and RISE^©) were produced by the same company, Globus Medical Inc. (Audubon, PA, USA). Meanwhile, the authors state that no funding has been received for this study and that all authors have no conflict of interest to disclose. If we take a look at the OpenPaymentData (https://openpaymentsdata.cms.gov/), not only can we see the disclosure of the senior author (and sole surgeon of the patients) but we can also see that a significant payment was received by the same author from Globus Medical Inc. (2). Of course, receiving a payment of a company does not necessarily mean that a study is not reliable. However, failure to disclose a financial conflict of interest does not only go against the journal’s policy but can also seen as scientific misconduct (3).

Aside from these ethical issues, there are also some scientific issues that warrant clarification. First is that the study is a single surgeon study which limits generalizability of the study data. Second, it is unclear at which time points the postoperative outcome measures were measured. Were all measurements conducted at 3 months? Or were some radiographs used that were conducted at one day postoperative?

Third is that an inappropriate test was used to compare continuous variables between two groups as the authors state that the “χ² sample Student t-test” was used.

Fourth is potential confounding by indication as the authors do not describe based on what criteria some patients received the SABLE^® or RISE^© cage.

Fifth, Fig. 2 supposedly shows magnetic resonance imaging, but only radiographs are shown in the picture. We would like to ask the authors to correct this.

Sixth is the remarkable failure of the surgery to improve the functional impairment of patients as measured on the ODI. Even though the indication for the MIS TLIF was degenerative disc disease, the patients only had a mean improvement on the ODI of 2 points (2%) which is far below the minimally clinically important difference of 15–20%. Based on this data, it can be concluded that the MIS TLIF does not improve functionality in patients with degenerative disc disease.

Seventh is the omittance of information regarding the radiographic measurements. Who conducted these measurements? Were they conducted by a radiologist or two radiologists? Where the measurements conducted blindly?

And finally is the issue with Tab. 2. For instance, there is no scientific added value of testing differences between postoperative measurements if they are not corrected for baseline values.

We invite the authors to discuss above points with us and perhaps clarify and/or correct some issues.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was a standard submission to the journal. The article did not undergo external peer review.

Conflicts of Interest: The author has completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-24-40/coif). The author has no conflicts of interest to declare.

Ethical Statement: The author is accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Jitpakdee K, Sommer F, Gouveia E, et al. Expandable cages that expand both height and lordosis provide improved immediate effect on sagittal alignment and short-term clinical outcomes following minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). J Spine Surg 2024;10:55-67. [Crossref] [PubMed]
2. Open Payment Data [Internet]. USA. [cited 2024 March 20]. Available online: https://openpaymentsdata.cms.gov/physician/137644
3. Botkin JR. Should Failure to Disclose Significant Financial Conflicts of Interest Be Considered Research Misconduct? JAMA 2018;320:2307-8. [Crossref] [PubMed]