Both types of leads convey electrical signals from the Ellipse implant to the spinal cord. The main difference is the shape of the leads and how they are implanted.
Percutaneous leads are thin, flexible cables which end in cylindrical electrode contacts. This type of electrode may be inserted through a needle and threaded into the spine under fluoroscopic x-ray. These leads are routinely used during a Stage I stimulator trial. Their advantage is the ease of insertion via minimally-invasive technique. Their primary disadvantage is the risk of the lead electrodes becoming dislodged from their desired position within the spine. This can result in loss of pain relief and may require revision surgery to resolve.
Surgical leads also have a thin, flexible cable but terminate in a paddle-shaped segment which is placed in the spinal canal through a surgical procedure called a laminotomy. A small portion of bone overlying the spinal cord (the lamina) is removed and the paddle is slid underneath between the bone and the membrane (dura) covering the spinal cord. The surgical lead is then fixated to the spine at the bone, making it resistant to dislodgment. The disadvantage of surgical leads is that the implantation procedure is more involved.
There are additional factors to consider when selecting a lead type. Please speak with your healthcare provider regarding the type of lead recommended for your particular situation.