Examination of needle surface corrosion in electroacupuncture.

BACKGROUND: Electroacupuncture (EA) is a modern form of acupuncture therapy where stainless steel acupuncture needles are used as percutaneous electrodes to apply electrical stimulation. The concern about electrolytic corrosion of needles during EA has not been conclusively addressed. AIM: To examine whether corrosion of stainless steel acupuncture needles occurs after EA to establish the safety profile of this therapy. METHODS: The study comprised four EA sessions on healthy participants mimicking a common clinical practice, with needle surface examinations conducted immediately after each session. Used acupuncture needles that did not undergo electrical stimulation and unused needles taken from the original package were also examined as control comparisons. Two commonly used types of single-use, silicone-coated, stainless steel needles were selected for the experiment. The ES-160 digital acupunctoscope (a charge-balanced electric stimulator) was used to deliver electrical stimulation, and an oscilloscope was used to record the waveforms and electric currents. All needles were sterilised before examination by a scanning electron microscope (SEM), where images of needle tips and shafts were taken for further analysis. RESULTS AND CONCLUSIONS: 32 needles were examined under the SEM. As the main findings, the SEM images showed the surface finish, burr attachments and surface characteristics of needle samples. No evidence of electrolytic corrosion was detected on any needle that underwent electrical stimulation for 30 min delivered by a charge-balanced acupunctoscope in healthy participants. The choice of a charge-balanced acupunctoscope is recommended to avoid any potential corrosion of needles in EA clinical practice.

Examination of surface conditions and other physical properties of commonly used stainless steel acupuncture needles.

OBJECTIVES: The present work examined the surface conditions and various other physical properties of sterilised single-use stainless steel acupuncture needles from two of the most popular brands widely used in many countries. METHODS: Scanning electron microscope (SEM) images were taken for 10 randomly chosen needles from each brand. Further SEM images were taken after each of these needles underwent a standard manipulation with an acupuncture needling practice gel. A comparison of forces and torques during the needling process was also carried out. RESULTS: The SEM images revealed significant surface irregularities and inconsistencies at the needle tips, especially for needles from one of the two brands. Metallic lumps and small, loosely attached pieces of material were observed on the surfaces of some needles. Some of the lumps and pieces of material seen on the needle surfaces disappeared after the acupuncture manipulation. If these needles had been used on patients, the metallic lumps and small pieces of material could have been deposited in human tissues, which could have caused adverse events such as dermatitis. Malformed needle tips might also cause other adverse effects including bleeding, haematoma/bruising, or strong pain during needling. An off-centre needle tip could result in the needle altering its direction during insertion and consequently failing to reach the intended acupuncture point or damaging adjacent tissues. CONCLUSIONS: These findings highlight the need for improved quality control of acupuncture needles, with a view to further enhancing the safety and comfort of acupuncture users.