Impact of Lipoma Size and Depth on Local Anesthetic Volume: Exploring the Efficacy of Diluted Lidocaine for Excision

Local anesthesia is commonly used in the surgical excision of lipomas. However, concerns regarding anesthetic toxicity and insufficient analgesia may arise in larger or deeper tumors. Tumescent anesthesia using highly diluted lidocaine has been proposed to mitigate these risks, though its clinical utility remains insufficiently studied. In this retrospective observational study, we evaluated the efficacy and safety of 10-fold diluted 1% lidocaine in the excision of 53 lipomas from 38 patients. We also investigated how tumor characteristics, including size and depth, influenced anesthetic volume and the choice of anesthesia (local vs. general). Local anesthesia was used in 86.8% of cases, whereas general anesthesia was typically reserved for deep-seated lipomas. Among cases performed under local anesthesia, total anesthetic volume was positively correlated with lipoma size (ρ = 0.666, p < 0.001), while the volume of undiluted 1% lidocaine showed only a weak correlation (ρ = 0.280, p = 0.084). Ten-fold diluted lidocaine was effective for providing adequate analgesia, even for large tumors, and its use reduced the need for general anesthesia. Our findings suggest that the use of highly diluted lidocaine is a safe and practical method in the outpatient excision of lipomas, especially when deeper lesions are avoided. This approach may help optimize anesthetic strategies by minimizing lidocaine dosage while maintaining analgesic efficacy. While lipoma depth remains a critical factor in anesthesia selection, the broader application of diluted local anesthetics could expand the role of local anesthesia in soft tissue surgery.