Intradiscal Electrothermal Therapy (IDET)

1. OVERVIEW
2. DIAGNOSIS
3. PROCEDURE

OVERVIEW
Intradiscal Electrothermal Therapy (IDET) is a minimally invasive procedure performed by physiatrists at Hospital for Special Surgery (HSS) that offers an important treatment option to individuals with lower back pain caused by lumbar disc disease.  Typically, candidates for IDET have moderate to severe pain for at least six months and have not responded adequately to more conservative care, such as oral anti-inflammatory medication, education to improve body mechanics, physical therapy, and less invasive procedures, such as fluoroscopic lumbar epidural steroid injections.

The intervertebral disc serves as a cushion between the individual vertebrae (building blocks) of the spine and is composed of a soft, gelatinous center surrounded by layers of tough fibrocartilage tissue, known as the annulus.  The outer layer of the annulus wall contains nerve endings and is responsible for pain generation when the disc is injured or diseased.  In the presence of tears of the disc, with or without small protrusions of disc material or herniations, pain may be caused by a mechanical irritation of the nerve endings due to injury extending to the wall of the disc as well as a chemical irritation in the form of inflammation.

Patients with painful tears of the annulus of the disc, with or without small protrusions of disc material, are the best candidates for IDET. Patients with severe disc space narrowing or large herniations are not candidates for the procedure.

DIAGNOSIS
Lumbar disc injury and disease are usually diagnosed through a combination of a comprehensive history and physical examination, a magnetic resonance imaging (MRI), and, sometimes, a lumbar discogram, a radiology-guided procedure that detects disc tears.

PROCEDURE
Intradiscal Electrothermal Therapy is a percutaneous (performed through the skin) procedure conducted under light sedation as an outpatient.  First, the physician inserts a needle through the skin of the back after the area has been thoroughly cleaned and numbed with a local anesthetic.  The physician then passes a thermal catheter through the needle and into the injured disc in the specific area of the annulus tear.

Lateral fluoroscopic image of the introducer needle and IDET catheter in the L4-5 disc.

Anterior-posterior fluoroscopic image of the introducer needle and IDET catheter in the L4-5 disc.

The catheter heats the collagen of the disc to shrink the protruded material and destroy the pain fibers. Following the procedure, a patient is enrolled in a carefully monitored rehabilitation program, which initially includes pain control, bracing, and rest. When ready, the patient advances into a physical therapy program to strengthen his or her back and abdominal muscles and eventually returns to normal activity. 

The IDET success rate at HSS based on long-term follow up has been favorable.[1]  Our prospective outcome study showed that approximately one-third of patients enjoy complete pain relief, one-third experience moderate pain relief, and the remaining one-third report no change in pain relief.[2]  For the latter group, physicians may recommend pursuing more aggressive surgical treatment.

HSS has not seen any serious complications from the IDET procedures. However, any invasive procedure of the spine carries the risk of infection and nerve injury.