The analgesic technique of spinal cord stimulation consists of the implantation in 2 stages of a device whose mission is to stimulate the posterior cords of the spinal cord that transmit normal sensitivity from the different parts of the body (except the head) to the brain. This stimulation of spinal cords produces a pleasant paresthesia (ant-like sensation) that should cover all or a large part of the area affected by chronic pain and, in this way, block the transmission of nerve impulses that carry the painful sensation to the brain, in line with the theory of the “pain gateway” described in 1965 by the Canadian psychologist Ronald Melzack and the British neuroscientist Patrick David Wall.
When should we use it?
This is achieved through electrodes implanted percutaneously in the posterior epidural space of the spinal column (a few millimeters from the spinal cord, but without coming into contact with it) in a first surgical stage in which the efficacy of the therapy is checked for about 10-15 days by obtaining the stimulus through an external generator. If during these days, the patient experiences a pain relief of more than 50%, we can indicate the implantation of the definitive generator. In this second stage, the small generator, similar to a pacemaker, with a rechargeable battery (wirelessly) would be implanted subcutaneously in the buttock region or in the lower-lateral region of the abdomen, to connect them to the electrodes already implanted previously and continue to maintain the electrical stimulus.
The use of this therapy, when appropriately indicated, allows patients to significantly reduce the use of analgesics and largely avoid their associated side effects and greatly improve their quality of life.
History of spinal cord stimulation
Although the first use of this technique dates back to 1967, when an American neurosurgeon, Dr. Clyde Norman Shealy, performed the procedure. Clyde Norman Shealy performed the first implant to treat chronic pain in a patient with bronchial carcinoma, it is not until the last 20 years, thanks to the improvement of the implant technique and the continuous technological advances that provide safer, smaller and more durable devices, that its use has become popular in pain units to treat those cases of severe pain that have not responded to pharmacological, infiltrative, rehabilitative and/or surgical treatments, with guarantees of efficacy and safety.
Indications
- Failed Back Syndrome, in which pain persists after surgical interventions on the lumbar spine. This is the indication most frequently treated and with the highest success rates.
- Complex Regional Pain Syndromes in extremities, also called Sympathetic Reflex Sympathetic Dystrophy, Algodystrophy, Sudeck’s Syndrome…, when infiltrative treatments aimed at achieving a permanent blockade of the Sympathetic Nervous System have failed.
- Peripheral nerve lesions.
- Chronic anginal pain in severe ischemic heart disease refractory to medical treatment.
- Pain due to severe chronic arterial ischemia of lower or upper limbs.
Contraindications
- Blood coagulation disorders.
- Infections or states of immunosuppression that may favor them.
- Severe vertebral instability with risk of progression.
- Inability of the patient to use the device.