Electrode Placement
The hallmark of a good neurophysiologist is accurate electrode placement that provides excellent recordings, minimal to no noise, is repeatable and reliable and doesn't get removed easily while the patient is under the drapes rendering a myotome unrecordable.
Good placement comes with an area that is properly prepped. It is Evoked Potential preference to use an operating room towel saturated with 70% Isopropyl rubbing alcohol. Massage/Scrub/Rub/Wipe the towel with over the areas that electrodes will be placed ensuring the area is clean. Fold and unfold the towel as necessary if and when it becomes dirty. This will ensure excellent contact with the electrode and a secure field for tape to adhere. Also provides for an area that will not get infected. Including and especially where the ground site is. The body and head need to be prepped in all areas.
For the scalp, ensure that a newly clean area of the towel is used and massage/scrub/rub/wipe the head where all electrodes will be placed including and especially where the ground electrode site is.
It is paramount, before any electrode is placed, that a seating plan is organized and agreed with the staff. Where do they want you to be, where will you sit, where will the pods be positioned at the bed for you to plug into where you can access them without violating the sterile field or impeding progress of the surgery. A little bit of strategy goes a long way.
Other questions to ask, will the patient be supine or prone, will the patient's arms be positing superman, tucked or lateral at sides? All of this information will let you know the proper placement of pods so you can access them both for immediate insertion once the patient is positioned but in case a stimulator will be added during the course of the surgery for identification of neural tissue. will the operating room be turned 90 or 180 degrees? If you have a choice, it is best to be in a position of triangulation where you can easily communicate with anesthesia and the surgeon; it is the Evoked Potential plan to be within eye contact and voice contact of each for effective communication. You want to be opposite of the scrub table so there is no chance of violating the sterile field.
Let's start with the ground, the most important electrode placed. What is a ground? It is a reference point for all electrode sites placed on the body. A pair of electrodes the ground, strategically placed in the most opportune area for the extremities being monitored and the positioning of the patient.
For a cervical case, in the shoulder, for a lumbar/sacral case, in the hip. The ground can typically be placed anywhere, however the closer to bone you are the better.
Let's take the shoulder for an example, a pair of electrodes are brought together to be placed at a singular point, placed at the shoulder girdle at the medial deltoid. It is placed at a 90 degree angle to the skin, the electrode tips are flattened against the skin toward the hands and the electrodes are secured by tape and then a tension loop is placed. If the patient is going to be supine for an ACDF and you are siting on the east side of the table, place the ground in the east shoulder. If it is a cervical case and the patient will be rotated to prone and you will be sitting on the east side of the table, place the electrode in the west shoulder so when the patient is rotated the ground is on your side. The same ideology takes place for a lumbar sacral position.
Let's start with ideal positioning using north, south, east and west as directions of the operating room table with the patient's head facing north.
Good placement comes with an area that is properly prepped. It is Evoked Potential preference to use an operating room towel saturated with 70% Isopropyl rubbing alcohol. Massage/Scrub/Rub/Wipe the towel with over the areas that electrodes will be placed ensuring the area is clean. Fold and unfold the towel as necessary if and when it becomes dirty. This will ensure excellent contact with the electrode and a secure field for tape to adhere. Also provides for an area that will not get infected. Including and especially where the ground site is. The body and head need to be prepped in all areas.
For the scalp, ensure that a newly clean area of the towel is used and massage/scrub/rub/wipe the head where all electrodes will be placed including and especially where the ground electrode site is.
It is paramount, before any electrode is placed, that a seating plan is organized and agreed with the staff. Where do they want you to be, where will you sit, where will the pods be positioned at the bed for you to plug into where you can access them without violating the sterile field or impeding progress of the surgery. A little bit of strategy goes a long way.
Other questions to ask, will the patient be supine or prone, will the patient's arms be positing superman, tucked or lateral at sides? All of this information will let you know the proper placement of pods so you can access them both for immediate insertion once the patient is positioned but in case a stimulator will be added during the course of the surgery for identification of neural tissue. will the operating room be turned 90 or 180 degrees? If you have a choice, it is best to be in a position of triangulation where you can easily communicate with anesthesia and the surgeon; it is the Evoked Potential plan to be within eye contact and voice contact of each for effective communication. You want to be opposite of the scrub table so there is no chance of violating the sterile field.
Let's start with the ground, the most important electrode placed. What is a ground? It is a reference point for all electrode sites placed on the body. A pair of electrodes the ground, strategically placed in the most opportune area for the extremities being monitored and the positioning of the patient.
For a cervical case, in the shoulder, for a lumbar/sacral case, in the hip. The ground can typically be placed anywhere, however the closer to bone you are the better.
Let's take the shoulder for an example, a pair of electrodes are brought together to be placed at a singular point, placed at the shoulder girdle at the medial deltoid. It is placed at a 90 degree angle to the skin, the electrode tips are flattened against the skin toward the hands and the electrodes are secured by tape and then a tension loop is placed. If the patient is going to be supine for an ACDF and you are siting on the east side of the table, place the ground in the east shoulder. If it is a cervical case and the patient will be rotated to prone and you will be sitting on the east side of the table, place the electrode in the west shoulder so when the patient is rotated the ground is on your side. The same ideology takes place for a lumbar sacral position.
Let's start with ideal positioning using north, south, east and west as directions of the operating room table with the patient's head facing north.