Core principle of dispersive pad placement
Electrosurgery completes its circuit through the patient. The active electrode delivers concentrated current at the surgical site, while the
dispersive electrode (return pad) collects that current over a wide surface area and carries it back to the generator. If the return pad has poor contact or is placed over tissue that cannot safely conduct current away, current density rises at that site and produces a
return-electrode burn .
The pad must be placed over a large, well-perfused muscle mass so that heat generated by current flow is rapidly dissipated by blood flow. Muscle has high water and electrolyte content, making it a good conductor. Adipose tissue, bone, scar tissue, and areas with poor vascularity are poor conductors and increase resistance, which raises local temperature .
Why each option is safe or unsafe for this client
| Site | Assessment | Verdict |
|---|
| Left anterior thigh | Large quadriceps muscle mass, well perfused, clean and dry, no scar or implant on that side, away from the surgical field (right inguinal area) | Correct — meets all placement criteria |
| Left buttock | Has a healed surgical scar from prior hip surgery; scar tissue is poorly vascularized and has higher impedance | Unsafe — scar increases resistance and burn risk |
| Lower back over the sacrum | Bony prominence with thin soft tissue coverage; poor muscle mass and risk of pressure-related poor contact | Unsafe — bony prominences concentrate current and impair pad contact |
| Right lateral thigh | Same side as the surgical site and near the path of current flow; also adjacent to the right hip replacement | Unsafe — proximity to the active electrode and metal implant increases risk |
The implant concern
This client has a right total hip replacement. Metal implants are conductive and can create unintended current pathways. Research using phantom models and simulations has shown that when a metallic implant lies between the active and dispersive electrodes, localized heating can occur around the implant even at routine power settings such as
20 W to
40 W .
The dispersive pad should be positioned so that the current path from the active electrode to the pad does not cross through or near the metal implant. Placing the pad on the left anterior thigh directs current away from the right hip prosthesis .
Practical placement checks
Before applying the pad, the circulating nurse should confirm the skin is
clean, dry, and hairless. Excessive hair should be clipped, not shaved, to avoid microabrasions that increase impedance. The pad must lie
flat with full contact — no wrinkles, no gaps, and no edges lifting. It should be placed as close to the surgical site as practical while remaining on intact skin and away from the active electrode path . The pad should also be positioned away from
bony prominences,
scar tissue,
metal implants, and
areas with excess adipose tissue .
Key point! The left anterior thigh is the only listed site that provides a large, well-perfused muscle mass on clean, dry, hairless skin, with no scar, no bony prominence, and no metal implant in the current path. The right lateral thigh is too close to the surgical site and the hip prosthesis; the left buttock has a healed scar; the sacrum is a bony prominence with thin tissue .