Efficacy of a Novel LAM Femoral Cutaneous Block Technique for Acute Donor Site Pain

Abstract

Patients with severe burn injuries often require split-thickness skin grafting to expedite wound healing with the thigh being a common donor site. Uncontrolled pain is associated with increased opioid consumption, longer lengths of stay, and delay in functional recovery. Peripheral nerve blocks are increasing in popularity although supportive literature is limited, and techniques vary. The purpose of this case series is to assess the safety, feasibility, and clinical efficacy of a recently demonstrated novel continuous LAM (lateral, anterior, medial) femoral cutaneous block technique in a larger cohort. The study was a dual IRB approved, observational case series from a single verified burn center. The electronic health record was retrospectively reviewed for patients admitted between June 2018 and May 2021 who had the continuous LAM block performed for donor site pain by the acute pain service team. Demographics were reported with descriptive statistics and morphine milligram equivalents (MME) were analyzed via Friedman analysis of variance. Forty-seven patients had a total of 53 blocks placed, where 2 patients received the LAM block on two separate occasions and 4 patients had bilateral LAM blocks placed. Most were African-American males, but mechanism of injury varied. Over half had a neurologic (17%) or psychiatric history (34%) outside of substance use. Almost three-quarters had a history of substance use with 17% being opioids, and a quarter had a history of polysubstance use. Median day from admission to LAM was 7 (2.5, 11.5) with a median duration of 4 (3, 5) days. Temperature and pressure sensation were reduced at the donor site. Quadricep strength remained intact, and median day until first ambulation after LAM placement was 2 (1, 3) days. Pain was adequately controlled, and there were no significant adverse events associated with the block. There was a significant reduction in MME after block placement (p < .001). Continuous peripheral nerve blocks offer an advantageous means of analgesia, while reducing potential adverse events associated with opioids or multimodal regimens. The novel LAM technique reduced sensation and pain without inhibiting early ambulation, and patients were able to fully participate in their rehabilitation.