Letter to Editor regarding “Ultrasound-guided erector spinae plane block versus modified thoracolumbar interfascial plane block in lumbar spine surgeries: A randomized controlled trial”

Dear Editor, We read with considerable interest the recent randomized controlled trial by Mogahed et al.[1] evaluating ultrasound-guided erector spinae plane block (ESPB) and modified thoracolumbar interfascial plane block (mTLIP) in lumbar spine surgeries. The study addresses a clinically relevant question in perioperative pain management, and the finding that both techniques reduce opioid consumption compared with control is noteworthy.[1] However, certain methodological aspects merit further consideration, as they may influence interpretation of the results. First, although patients undergoing “single-level lumbar spine surgery” were included, the specific vertebral levels operated (e.g., L2–L3, L4–L5, L5–S1) were not reported.[1] This is an important omission, as postoperative pain intensity may vary depending on the surgical level and extent of tissue trauma.[2] An unequal distribution of surgical levels between groups could therefore confound opioid consumption and pain scores, independent of the regional technique used. Clear reporting and, where appropriate, adjustment for this variable would enhance the robustness of the findings. Second, the two interventions were performed at different anatomical levels—ESPB at T10 and mTLIP at L3.[1] These techniques differ in both mechanism of action and pattern of spread.[3] While ESPB relies on variable cranio-caudal diffusion from a thoracic injection point, mTLIP provides a more localized lumbar plane block.[3,4] In the absence of alignment between block level and surgical site, or objective confirmation of dermatomal coverage, the comparison may not be entirely equivalent, thereby limiting conclusions regarding comparative efficacy. Furthermore, intraoperative fentanyl administration was titrated according to hemodynamic responses and was lower in the block groups.[1] Given that postoperative fentanyl consumption was the primary outcome, this introduces a potential confounding factor.[5] A standardized intraoperative analgesic protocol or statistical adjustment would have strengthened the internal validity of the study. Additionally, the exclusion criteria do not clarify whether patients with prior spine surgery were omitted.[1] This is relevant, as previous surgical interventions may alter paraspinal anatomy and disrupt fascial planes, potentially affecting the efficacy of ESPB and mTLIP blocks. The inclusion of such patients without explicit reporting may therefore confound the observed outcomes. The authors conclude that ESPB “potentially offers an advantage” in opioid reduction; however, this appears inconsistent with the comparable fentanyl and morphine consumption reported between the ESPB and mTLIP groups.[1] A more cautious interpretation may be warranted. Finally, the absence of a sham block and incomplete blinding may introduce bias, particularly for subjective outcomes such as pain scores and patient-controlled analgesia usage.[1] Considering these considerations, the conclusion that ESPB and mTLIP are comparable should be interpreted with caution. Future studies with detailed reporting of surgical levels, alignment of block level with the operative site, and rigorous control of confounding variables would provide more definitive evidence. We declare no conflicts of interest. Data availability statement Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study. Ethical approval statement Ethics approval was not required for this case article. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.