Fine Wire Electrodes
We offer two different types of fine wire electrode, each electrode comprising of two sterilized fine-wires with hooked ends suitable for intra muscular recordings supplied in different length needles. The shorter 30mm needles are used for shallow insertions, while the longer 50mm needles are suitable for placement in deeper muscles.
Both lengths of fine wire electrode are supplied in boxes of ten (10) electrodes - each electrode is supplied in an individual sterilized package, ready for use without requiring any special preparation. All electrodes have a minimum expiration period of one year from the date of purchase.
The completed assemblies are sterilized by gamma radiation, minimum dose of 25kGy with the sterilization validated using the VD-max method (AAMI TIR 27). Nelson Labs in Salt Lake City, UT performs lab testing services for the electrode manufacturer in conjunction with Sterigenics (the contract irradiator).
Each pair of wires is 200mm (~8 inches) long. The individual wires are 0.002" (0.051 mm) diameter, 304 series stainless steel with green nylon insulation for improved visibility. Each pair of wires has bare hooked sensor ends (The insulation is offset to avoid short circuits) in the cannula.
The equipment connection ends of each pair of wires are clean and free of insulation suitable for connection to any EMG system designed for bi-polar, intra muscular, fine-wire recording.
The Nickel Directive
Our fine wire electrodes and preamplifiers sensors are made with surgical grade stainless steel to ensure compliance with the 14th Amendment to European Directive 76/769/EEC is known as ‘The Nickel Directive’ or, more correctly, as the ‘European Parliament and Council Directive 94/27/EC’ which is summarized below. This Directive defines unsuitable products in three classes of use. Basically these are:
- Post assemblies, used to maintain an open hole during the healing of wounds after body piercing, must be homogenous and must not contain more than 0.05% of nickel.
- Products intended to come into direct and prolonged contact with the skin must not release soluble nickel at a rate in excess of 0.5 microgram/cm²/week, when tested in artificial sweat according to standard EN 1811:1998.
- Nickel, or nickel alloy coated products, as defined in ‘2’ above, shall not release nickel in excess of 0.5 microgram/cm²/week after two years of normal use, when tested according to standard EN 12472:1998.
In the first category, we are concerned that, while this directive is primarily aimed at jewelry and piercing, the possibility of leaving small particles of wire in the body when a traditional nickel alloy fine wire is withdrawn from the muscle could bring the traditional nickel alloy wire electrodes into violation of the Directive. As a result we use medical grade stainless steel wire in the construction of our fine-wire electrodes.
The second category applies to the stainless steel sensors which, according to the Directive, must not release nickel at a rate greater than 0.5 microgram/cm²/week in the EN1811 test - which our preamplifier disks easily meet.
The third category covers similar articles to the second, but relates to coated materials that must not release nickel at a rate greater than 0.5 microgram/cm²/week after two years of normal use. Motion Lab Systems does not use any nickel coated materials.