Editing Electromyography (section)

===Skin preparation and risks===
The first step before insertion of the needle electrode is skin preparation. This typically involves simply cleaning the skin with an alcohol pad.{{citation needed|date=December 2021}}

The actual placement of the needle electrode can be difficult and depends on a number of factors, such as specific muscle selection and the size of that muscle. Proper needle EMG placement is very important for accurate representation of the [[muscle]] of interest, although EMG is more effective on superficial muscles as it is unable to bypass the action potentials of superficial muscles and detect deeper muscles. Also, the more [[body fat]] an individual has, the weaker the EMG signal. When placing the EMG sensor, the ideal location is at the belly of the muscle: the longitudinal midline. The belly of the muscle can also be thought of as in-between the motor point (middle) of the muscle and the tendonus insertion point.{{citation needed|date=December 2021}}

[[Cardiac pacemaker|Cardiac pacemakers]] and implanted [[Defibrillation|cardiac defibrillators]] (ICDs) are used increasingly in clinical practice, and no evidence exists indicating that performing routine electrodiagnostic studies on patients with these devices pose a safety hazard. However, there are theoretical concerns that electrical impulses of [[Nerve conduction study|nerve conduction studies]] (NCS) could be erroneously sensed by devices and result in unintended inhibition or triggering of output or reprogramming of the device. In general, the closer the stimulation site is to the pacemaker and pacing leads, the greater the chance for inducing a voltage of sufficient amplitude to inhibit the pacemaker. Despite such concerns, no immediate or delayed adverse effects have been reported with routine NCS.{{citation needed|date=December 2021}}

No known contraindications exist for performing needle EMG or NCS on pregnant patients. Additionally, no complications from these procedures have been reported in the literature. Evoked potential testing, likewise, has not been reported to cause any problems when it is performed during pregnancy.<ref name="aanem.org">{{cite web |title=Not Found – American Association of Neuromuscular & Electrodiagnostic Medicine |url=http://www.aanem.org/getmedia/2034191e-583b-4c55-b725-fc38ea8262e2/risksinEDX.pdf.aspx. |url-status=dead |archive-url=https://web.archive.org/web/20230225222910/https://www.aanem.org/Not-Found?aspxerrorpath=/getmedia/2034191e-583b-4c55-b725-fc38ea8262e2/risksinEDX.pdf.aspx. |archive-date=2023-02-25 |access-date=2014-12-26 |website=www.aanem.org}}</ref>

Patients with [[lymphedema]] or patients at risk for lymphedema are routinely cautioned to avoid percutaneous procedures in the affected extremity, namely [[venipuncture]], to prevent development or worsening of [[lymphedema]] or [[cellulitis]]. Despite the potential risk, the evidence for such complications subsequent to venipuncture is limited. No published reports exist of cellulitis, infection, or other complications related to EMG performed in the setting of lymphedema or prior lymph node dissection. However, given the unknown risk of cellulitis in patients with lymphedema, reasonable caution should be exercised in performing needle examinations in lymphedematous regions to avoid complications. In patients with gross edema and taut skin, skin puncture by needle electrodes may result in chronic weeping of serous fluid. The potential bacterial media of such serous fluid and the violation of skin integrity may increase the risk of cellulitis. Before proceeding, the physician should weigh the potential risks of performing the study with the need to obtain the information gained.<ref name="aanem.org"/>