BID FAREWELL
TO PAIN

Spinal Cord Stimulator – A boon for patients
with pains of Neuropathic origin

Spinal Cord Stimulation is a therapy that masks pain signals before they reach the brain. A small device called the Spinal Cord Stimulator is implanted in the body for the same.

How It Works: Spinal Cord Stimulation is based on the gate control theory of pain proposed by Wall and Melzack. Pain is felt because nerves send the pain signal to the brain. This pain transmission occurs through the ‘gate’ in substantia gelatinosa in the dorsal aspect of the spinal cord. At the gate, both myelinated fibre (which transmits pressure, touch and vibration) and unmyelinated fibres (which transmits pain) try to pass messages through the synapse. However, through the gate, only one message can pass through at a time; either through myelinated fibres or unmyelinated fibres. The message through myelinated fibres is preferred over unmyelinated ones.

Spinal Cord Stimulator is a small device implanted inside the body (like a pacemaker), which has a pulse generator with a battery and thin wires called ‘leads”. It is operated through an external handheld remote control. When the patient feels pain, he presses the remote, electrical pulses are generated which are carried by leads to the spinal cord that blocks the pain signals through the ‘gate’ travelling to the brain. Instead of pain, the patient feels a vibration/fluttering sensation that replaces the pain. Stimulation does not eliminate the source of pain, it simply interferes with the signal to the brain, and so the amount of pain relief varies for each person.

Indications: Spinal Cord Stimulation is particularly effective for relieving the pain of neuropathic origin. The most common indications include –

• ♦ Failed Back Surgery Syndrome (FBSS)
     with radicular pain
• ♦ Complex Regional Pain Syndrome (CRPS)
• ♦ Cervical and Lumbar Radiculopathy
• ♦ Arachnoiditis
• ♦ Peripheral Neuropathy
• ♦ Intractable pain from Postherpetic
     Neuralgia
♦ Phantom Limb pain
• ♦ Ischemic Limb pain

The Surgical Process: Implantation of the Spinal Cord Stimulator is a two-step process. Since the amount of pain relief varies for each person and some patients find the tingling sensation unpleasant, a trial stimulation is performed before the device is permanently implanted.

Stage 1. Trial Spinal Cord Stimulation:
Trial stimulation is a "test drive" to determine if a Spinal Cord Stimulator will work for the type, location, and severity of the pain. It is performed under local anaesthesia. Using X-ray, a hollow needle is inserted through the skin into the epidural space between the bone and spinal cord. The trial lead is inserted and positioned over specific nerves. The wires are attached to an external generator worn on a belt. After 4 to 7 days, the decision to permanently implant the stimulator is taken based on the improvement in pain.

Stage 2. Permanent Spinal Cord
Stimulation: If the trial is successful and there is greater than 50% improvement in pain, surgery can be scheduled to permanently implant the Spinal Cord Stimulator. The Spinal Cord Stimulator will be placed in the body, depending on the site of pain. For Chest wall common lead placement target is T1-T2, for Back and Legs T7-T9, for legs T10, and for pelvis L1.