Letter to the Editor Regarding “Testosterone Replacement Therapy in Posterior Lumbar Fusion Patients: A Propensity Score-matched Analysis of Long-Term Outcomes”

Dear Editor,

We read with great interest the article by Miller et al., ¹ titled “Testosterone Replacement Therapy in Posterior Lumbar Fusion Patients: A Propensity Score-Matched Analysis of Long-Term Outcomes”, published in *Global Spine Journal*. The authors should be commended for addressing a timely and clinically relevant question regarding testosterone replacement therapy (TRT) in patients undergoing posterior lumbar fusion (PLF). Their large propensity score-matched analysis provides valuable preliminary evidence that TRT exposure may be associated with lower short-term readmission and emergency department utilization but higher long-term revision PLF rates. This apparent divergence between early recovery and later surgical burden is clinically important.

However, we wish to highlight a critical issue regarding interpretation of the most clinically consequential finding: increased revision PLF cannot be fully understood without knowing why revision surgery occurred. TRT exposure was associated with higher revision PLF at one and two years, whereas pseudarthrosis, implant displacement, and surgical site infection were not significantly different between groups. This raises an important question as to whether the revision signal reflects adjacent segment disease, recurrent stenosis, persistent symptoms, unrecorded implant-related problems, surgeon practice patterns, or other indications. Without operative reports, imaging findings, patient-reported outcomes, or adjudicated revision indications, revision PLF remains a meaningful but nonspecific endpoint. Interpretation is further complicated by the exposure definition: documentation of TRT use within one year before surgery does not establish dose, route, treatment duration, adherence, achieved serum testosterone levels, indication for therapy, or perioperative discontinuation and resumption. These factors may influence both perioperative recovery and longer-term outcomes and therefore limit attribution of the observed revision association to TRT itself. Accordingly, the higher revision rate should be viewed as hypothesis-generating rather than evidence of a direct adverse effect of TRT on fusion biology or mechanical failure after PLF. Future studies incorporating TRT dose and duration, serum testosterone levels, perioperative management, imaging findings, and adjudicated indications for revision would help determine whether TRT represents a modifiable risk factor or instead identifies a clinically distinct patient population. We appreciate the valuable contribution of Miller et al. Their findings warrant further investigation, but greater clinical granularity is needed before TRT-associated revision risk is translated into specific preoperative counseling or postoperative surveillance strategies.

Sincerely,

Author name and affiliation withheld for peer review.

ORCID iD

Zhiwan Chen https://orcid.org/0009-0004-6181-3141