To the Editor,

Percutaneous Needle Electrolysis Therapy (PNET) is a relatively recent technique introduced by Sánchez-Ibáñez in Spain during the early 2000s. It has gained rapid popularity and adoption in Western Europe. The procedure involves applying a short galvanic current to a specifi c musculoskeletal target area by inserting percutaneous acupuncture-like needles [1]. The technique is easy to learn and perform and is utilized for treating various musculoskeletal conditions. It involves applying a brief galvanic current to a specific target area, with ultrasound assistance sometimes used for precise placement of the needles. The current creates local NaOH, acting as a caustic agent that dissolves damaged collagen fibers and other tissue debris. As a result, PNET’s therapeutic effect is based on a non-thermal ablation of the affected region, leading to a controlled local infl ammatory response. This response activates phagocytosis and promotes soft tissue regeneration [2]. Abat et al. [3] investigated the potential mechanisms of PNET on muscle injuries in a mouse model. Their fi ndings indicated that PNET could infl uence infl ammatory mediators and neovascularization in the injured area. They observed a reduction in plasma levels of pro-infl ammatory cytokines like tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). Additionally, PNET led to an increase in the expression of anti-infl ammatory mediators (PPAR-gamma) and proangiogenic factors (vascular endothelial growth factor (VEGF) and VEGF receptor-1 [VEGF-R1]).

PNET has gained significant popularity as a treatment for chronic soft-tissue overuse injuries, especially within the realm of sports medicine. Numerous studies have reported the effectiveness of this technique in non-acute conditions [4]. The therapy typically involves the application of the direct current for several minutes, followed by a period of rest. The duration and frequency of therapy sessions will depend on the specific condition being treated and the severity of the symptoms. The dosage of PNET varied based on the intensity and duration of the galvanic current application. High-intensity treatments were administered for short durations, ranging from 1 to 6 mA, ranging from 3 to 10 seconds. On the other hand, low-intensity treatments involved prolonged application times, with intensities ranging from 0.3 to 1 mA and lasting between 50 and 80 seconds. PNET usually is applied once a week, the total duration of the treatment differed ranging from 2 to 8 sessions based on clinical improwement [5]. A sample of PNET and its application is given in Figure 1.

PNET’s use has extended to various other medical conditions, including epicondylagia, carpal tunnel syndrome, proximal hamstring tendinopathy, injuries of the hamstring and rectus femoris muscles, plantaris tendon disorder, achilles tendinopathy, chronic soleus injuries, inguinal pain, whiplash syndrome, temporomandibular myofascial pain, subacromial pain syndrome, and patellofemoral pain syndrome [5].

PNET is considered a safe technique; however, adverse effects that may arise from its application can be attributed to either the needling process or the applied electric current. Commonly encountered are transient pain and mild vasovagal responses, which are inherent to the stimulation caused by needling and the electric current utilized. To mitigate vasovagal reactions, it is recommended to administer the treatment with the patient in a supine position [6].

Figure 1. A Sample of Percutaneous Needle Electrolysis Therapy and Its Application

PNET differs from other electrical currents used in the treatment of musculoskeletal disorders in several ways. One of the main differences between PNET and other electrical currents, such as transcutaneous electrical nerve stimulation (TENS) and peripheral nerve stimulation (PNS), is that PNET is delivered directly to the affected tissue.

TENS uses a low-frequency electrical current to stimulate the nerves in the affected area, which can help to alleviate pain. However, TENS does not stimulate tissue regeneration in the same way as PNET. Another difference between PNET and TENS is the depth of penetration. PNET is delivered through a needle electrode that is inserted into the affected tissue, which allows for the electrical current to penetrate deeper into the tissue. This can be particularly beneficial in the treatment of musculoskeletal disorders that involve deep tissue structures, such as tendons and ligaments.

Another treatment that is similar to PNET therapy is PNS. PNS, a neuromodulation therapy, is a commonly used approach to treat chronic and focal intractable pain by electrically modulating peripheral nerves. It involves a minimally invasive procedure that places a small electrical device (a wire-like electrode) next to one of the peripheral nerves [7]. PNS is implanted using ultrasound and/or fluoroscopic guidance or an open surgical approach along a named peripheral nerve or branches of a named nerve. PNS treatment is also different from PNET, which is a regenerative treatment method, in that it is a pain reliever treatment like TENS.

PNET therapy is important because it is a regeneration therapy that has similar effects to platelet-rich plasma and prolotherapy, unlike other analgesic currents such as TENS and PNS. PNET therapy is promising in terms of being both an effective analgesic and a regenerative treatment.

The most important step of PNET is the necessity of applying it under ultrasound guidance. Ultrasonography utilizes high-frequency sound waves to visualize the internal structures of tissues. During PNET, the use of ultrasonography offers several important advantages:

．Precise needle placement: Ultrasonography enables accurate placement of the needle into the targeted tissue. Proper needle placement enhances the effectiveness of the treatment by directly targeting the affected tissue and reducing the risk of damage to surrounding tissues.

．Visual guidance: Real-time visual monitoring of needle insertion is possible with ultrasonography. It serves as a guiding tool throughout the treatment process, ensuring accurate targeting of the treated area.

．Tissue assessment: Ultrasonography can be used to assess the condition and structure of tissues. By utilizing ultrasonography before and after the treatment, the healing process of the tissues can be monitored, and the suitability of the treatment can be evaluated.

．Reduction of side effects: The use of ultrasonography helps reduce the risk of affecting vital anatomical structures such as nerves or blood vessels with the needle. Real-time visualization facilitates the safe application of the treatment.

The incorporation of ultrasonography in PNET can enhance treatment effectiveness and minimize the risk of complications. However, it is important to have the necessary equipment, competence, and experience to utilize ultrasonography properly. Therefore, healthcare professionals performing PNET should develop their ultrasonography skills and follow current guidelines to manage the treatment process effectively.

In conclusion, PNET is an effective and safe treatment option for musculoskeletal disorders. It is my hope that more clinicians will consider PNET as a potential treatment option for their patients with musculoskeletal disorders.