A colonoscopy is a common, minimally invasive procedure used to screen for and prevent colorectal cancer. Since this procedure takes place under sedation in a hospital or clinic, patients must follow specific pre-procedure instructions. One consistent regulation across nearly all healthcare facilities is the complete removal of all metal jewelry. This mandate protects the patient from several potential safety hazards arising when metal objects are brought into a medical environment involving specialized equipment.
Electrosurgical Risks During the Procedure
The primary reason for removing metal jewelry relates to the use of electrosurgery, a technique frequently employed during a colonoscopy. If a polyp is identified, the endoscopist uses an electrosurgical unit (ESU) for removal (polypectomy). This process uses high-frequency electrical current to cut tissue and simultaneously cauterize blood vessels, preventing bleeding.
In monopolar electrosurgery, the electrical current travels from the cutting instrument, through the patient’s body, and is directed back to the ESU generator via a dispersive electrode, commonly called a grounding pad. Metal jewelry interferes with this circuit because it conducts electricity. If jewelry is in contact with the skin, it can provide an alternative, smaller pathway for the current to exit the body.
This redirection of electrical energy through a small surface area, such as a ring or a necklace, can cause a dangerous localized buildup of heat. This concentration of energy leads to severe thermal burns on the skin where the metal touches. Equipment malfunctions or a dislodged grounding pad increase the risk of stray current seeking a metal pathway. Removing all jewelry is mandatory to eliminate this burn risk, as all metals conduct electricity.
Practical and Physical Safety Concerns
Beyond the electrical risks, wearing jewelry presents mechanical and logistical challenges for patient safety. Once sedated, patients cannot control their movements or protect themselves from minor physical hazards. Jewelry, especially necklaces, bracelets, and rings, can easily snag on monitoring cables, linens, or the hospital gown during patient transfers or positioning.
Snagging jewelry could result in minor skin tears or injury if the item is pulled forcefully. Loose items like watches or earrings also risk being misplaced or lost during transfer to the recovery area. Healthcare facilities recommend leaving all valuables at home to avoid claims of loss or damage. Rings can also become problematic if the patient experiences unexpected swelling, potentially requiring the ring to be cut off.
Clarifying the Scope of the Rule
The rule requiring removal applies to all external metal items, including rings, watches, bracelets, necklaces, earrings, and body piercings. This regulation applies even if the items are not near the procedure site. Any metallic item, including dental appliances, may need to be removed or disclosed to the medical team.
For body piercings that are difficult or impossible to remove, patients should contact the endoscopy unit ahead of time for guidance. Fixed metal piercings must often be replaced with a non-conductive retainer made of materials like plastic, glass, or PTFE. Covering a metal piercing with tape is not sufficient to mitigate the electrical burn risk, as tape only helps prevent loss.