Percutaneous Electrical Nerve Stimulation (Pens) for the Treatment of Post-Mastectomy Pain Syndrome (Pmps): A Case Report

INTRODUCTION Post-mastectomy pain syndrome (PMPS) is a chronic post-surgical pain that can be severe and incapacitating [1]. We present a case of a patient who underwent percutaneous electrical nerve stimulation (PENS) for pain in the surgical wound after a radical mastectomy accompanied by ipsilateral axillary lymphadenectomy. For the purpose of influencing the nerve's distal distribution, stimulation is usually applied close to the area of pain. PENS is a minimally invasive neuromodulation technique that acts at the subcutaneous level and is effective for certain types of chronic pain. PENS has demonstrated an effect on Aβ nerve fibers and the localized release of various biochemical agents, such as endorphins and neurotransmitters. During PENS, a needle probe of varying length (area dependent) is inserted into the skin. The probe is tunneled percutaneously along the axis of the painful area, typically within the subcutaneous tissue at a depth between 0.5 cm and 3.0 cm, and then activated. This is a conventional stimulation protocol derived from published research indicating enhanced release of enkephalins, beta-endorphin, and endomorphin with 2-Hz stimulation and of dynorphin with 100-Hz stimulation [2]. Consent for publication was provided. METHODS The databases of PubMed were examined for observational studies, reviews, and case reports related to PMPS and PENS. The investigation targeted the terms ‘postmastectomy pain syndrome’ and ‘percutaneous electrical nerve stimulation’. Works published from 2000 to 2025 in English were included. RESULTS A 42-year-old Caucasian female weighing 55 kg presented to our outpatient clinic for reported pain of the left post-radical mastectomy surgical scar, arising 6 months after breast reconstruction surgery, which occurred in 2019. The discomfort was described as tingling, hypoesthesia, hyperalgesia, numbness, and a sensation of burning. This was initially managed with paracetamol and NSAIDs. At her initial consultation (T0), she rated her pain severity at a constant 8/10 on the Numerical Rating Scale (NRS) and 5/10 on Dolour Neuropatique 4 (DN4). It was decided to treat the painful area in two sessions, dividing the medial and lateral areas. A PENS therapy device and a 22-gauge flexible probe with an 80 mm active length were used, which alternates between 100 Hz and 2 Hz every 3 seconds for 30 minutes. Respecting the patient's comfort, the stimulation intensity varied from 1 mA to 20 mA. After 30 days (T1), the results on the treated medial area were NRS 4/10 and DN4 0/10. So it was decided to treat the affected lateral area as well. At the last check-up, after a further 30 days (T2), the patient reported NRS 1/10 and DN4 0/10 over the entire treated area. CONCLUSIONS We propose that PENS may represent a safe and effective treatment for PMPS. Given that the existing literature shows potential yet remains scarce, additional case reports and research on PENS use in post-mastectomy patients who have not experienced long-term benefits from other treatments are needed.