Abstract
To the Editor,
We read with great interest the recent article by Diego Garcia and colleagues investigating the association between preoperative vitamin D deficiency and postoperative complications following single-level lumbar fusion. 1 The authors should be commended for conducting a large propensity score–matched analysis demonstrating that vitamin D deficiency was associated with increased short-term medical complications and higher long-term risks of pseudoarthrosis and revision surgery. This study provides important evidence supporting the growing recognition of metabolic and nutritional optimization as an essential component of perioperative spine care.
Nevertheless, several issues merit further discussion. First, the study defined vitamin D deficiency using a threshold of <20 ng/mL, which is consistent with many endocrine society guidelines. 2 However, the optimal serum vitamin D level for musculoskeletal health and spinal fusion remains controversial. While some earlier guidelines recommended maintaining serum 25-hydroxyvitamin D levels above 30 ng/mL in at-risk populations, 3 more recent guidance from the Endocrine Society in 2024 no longer endorses strict definitions of vitamin D “sufficiency” or “insufficiency” based on fixed serum thresholds. 4 This evolving perspective highlights the ongoing uncertainty regarding the most clinically relevant vitamin D target for patients undergoing spinal fusion. Accordingly, future studies should investigate whether a dose-response relationship exists between varying degrees of vitamin D deficiency and postoperative outcomes. Stratification into severe deficiency, insufficiency, and sufficient vitamin D groups may provide more clinically meaningful insights for perioperative risk stratification and metabolic optimization.
Second, the study assessed vitamin D status using a single preoperative 25-hydroxyvitamin D measurement. However, vitamin D levels may fluctuate considerably during the perioperative period as a result of postoperative inflammation, reduced mobility, altered nutritional intake, and recovery-related metabolic changes.5,6 Accordingly, serial monitoring of vitamin D levels at multiple postoperative time points may provide a more comprehensive understanding of the relationship between vitamin D status and spinal fusion outcomes. Future prospective studies evaluating dynamic perioperative vitamin D changes may help clarify whether persistent postoperative deficiency, rather than isolated preoperative deficiency alone, is more strongly associated with pseudarthrosis and revision surgery.
In addition, the findings of this study may have important implications from a healthcare systems perspective. Because vitamin D deficiency was associated with increased risks of readmission, surgical site infection, pseudarthrosis, and revision surgery, routine preoperative vitamin D screening and optimization could potentially represent a cost-effective perioperative intervention. Although vitamin D testing and supplementation are relatively inexpensive, revision lumbar fusion and postoperative complications are associated with substantial healthcare utilization and financial burden. Future investigations should therefore evaluate the cost-effectiveness of routine perioperative vitamin D assessment using metrics such as quality-adjusted life years, hospitalization costs, and revision-related expenditures. Such analyses may help determine whether preoperative vitamin D optimization provides not only clinical benefit but also economic value in spine surgery populations.
Overall, Garcia et al. should be congratulated for addressing an important and increasingly recognized aspect of perioperative spine care. Their findings further support the role of preoperative metabolic assessment in patients undergoing lumbar fusion and provide a strong rationale for future prospective and interventional studies.
