Risk of Burns from Jewelry NOT Removed During Surgery

It is common practice to require patients to remove all metal jewelry before surgery due to risk of skin burns. But how significant is this risk? Why would it even happen?

During surgery, electric cautery is very commonly used to stop any bleeding. The device used, called a monopolar, has a small metal tip when electrically active, can result in an electrically induced burn to any tissue it touches. This is analogous to how some people can accidentally electrocute themselves when taking a bath when a plugged in radio falls into the water.

Monopolar Cautery

Unlike a radio in water where the electricity is sent directly to the entire body, when it comes to bleeding during surgery, a monopolar device similarly sends an electric current through the patient's body BUT only at point of contact. However, because the metal tip has a tiny surface area, ALL of the electric current emitted is directly transmitted to any soft tissue it touches only at the point of contact (analogous to an adult putting all their weight on top of a stilleto heel causing the ground to indent at point of contact). The soft tissue acts as a point of high resistance which is why it burns at that specific point and nowhere else. From there, the electric current is diffusely sent out through the patient's entire body and towards a large surface grounding pad, typically placed on the thigh or back (when doing ENT surgery). The rest of the patient's body is unaffected as the electric current flows through from monopolar to grounding pad (path of least resistance; the grounding pad being a point where resistance to an electric current is very low).

Theoretically, if there is any metal (ie metal jewelry) between the monopolar and grounding pad, those areas can build up electricity and cause a burn. However, this would only occur if there is resistance which should not theoretically occur as long as the grounding pad is properly applied, as again, this is the path of least resistance for an electric current to go through and not any metal jewelry.

Grounding Pad

Similarly, metal retractors and metal instruments used during surgery does not cause tissue burns when a monopolar device is used due to either the large surface area of the metal (ie retractor) or due to distance from where the monopolar is utilized. However, as any surgeon knows, we can deliberately use a metal surgical tool, whether clamp or forceps, to burn the tissue by touching the monopolar to the metal instrument. Sometimes, even without touching, an electric spark or arc can be created between the monopolar and metal instrument when brought into close proximity.

As such, risk of burns from having metal jewelry on the body has a very low, but not zero, risk of causing burns to the skin when electrocautery is used during surgery due to long distance from where monopolar being used and grounding pad (assuming proper application) being the path of least resistance to the electric current.

That said, given this (low) risk can be completely and easily avoided by removal, it is customary to require all patients to remove any metal jewelry before surgery.

As an aside, putting tape over metal jewelry does absolutely nothing in terms of burn risk. It's really just a reminder for everyone that the jewelry is there.