Pulsed Electromagnetic Field (PEMF) Dosing Regimen Impacts Pain Control in Breast Reduction Patients
Erin Taylor, B.A.1, Krista Hardy, B.A.1, Amanda Alonso, B.A.1, Arthur Pilla, PhD2, Christine Rohde, M.D., M.P.H., F.A.C.S.1.
1Division of Plastic Surgery, Columbia University Medical Center, New York, NY, USA, 2Departments of Biomedical Engineering, Columbia University and Orthopedics, Mount Sinai School of Medicine, New York, NY, USA.
Non-invasive pulsed electromagnetic field (PEMF) therapy significantly accelerates pain reduction and decreases narcotic requirements after breast reduction (BR) and autologous flap breast reconstruction. PEMF is known to rapidly augment nitric oxide (NO) normally released in injured tissue, which can lead to accelerated pain relief. NO signaling is dynamic and self-regulating. Therefore, this study was designed to assess whether PEMF regimen could modulate its effect on post-op pain decrease in BR patients.
The original BR study was double-blind, randomized, and placebo-controlled (PRS, 2010). This study adds two groups of active BR patients treated with the identical PEMF signal applied at different time intervals (regimen). The original regimen was 20 min PEMF every 4 hours, “Q4” (n=12). The new regimens were 15 min. PEMF every 2 hours, “Q2” (n=13), and 5 min PEMF every 20 minutes, “5/20” (n=13). Pain scores by patient-assessed visual analog scale (VAS) and narcotic use in Percocet equivalents were recorded starting at one hour post-op until discharge (within 24 hrs post-op).
VAS scores are summarized in Fig. 1, which shows that the overall rate of pain decrease, normalized to 1 hr post-op, was not significantly different for Q4 and Q2 regimens P <0.01), whereas that for the 5/20 regimen was not significantly different from Q4 shams (P = 0.618). Pain at 24 hrs post-op was 41% and 32% of pain at 1 hr. for Q4 and Q2, respectively (P < 0.01). In contrast, pain at 24 hrs for 5/20 was 85% of pain at 1 hr, compared to 73% for Q4 shams (P = 0.215). Concomitantly, post-op narcotic usage for 5/20 was not different from Q4 shams, and approximately 2-fold higher compared to Q4 and Q2 regimens by 24 hrs (Fig. 2).
This study provides evidence that dosing of PEMF therapy modulates its effect on clinical outcomes. There was no significant difference between Q4 and Q2 regimens on the rate of post-op pain relief, which justifies the use of Q4 shams. The 5/20 regimen increases NO in the wound bed 4-fold faster than Q4, which may be large enough to augment natural negative feedback mechanisms controlling the rate of increase of NO in a wound. The dose effect of regimen reported here is supported by results from human fibroblast cultures, which show PEMF-enhanced NO release can be blocked if PEMF enhances both NO and phosphodiesterase (PDE) activity, which can reduce or inhibit PEMF-augmented NO release.
Fig 1: Effect of PEMF regimen on post-op pain reduction.
Fig 2: Effect of PEMF regimen on post-op narcotic requirements (Percocet equivalents).
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