Pain is a defence mechanism, but sometimes it is so intense and lasts so long that it becomes a problem. Acute pain can be controlled with medication, but when it comes to chronic pain the situation becomes much more complicated. Though the dose of medication is increased, there comes a time when either the pain is no longer controlled or the side effects are such that the medication cannot be increased further. This is especially common in patients with cancer.
If the pain affects just one side of the body (left or right), or an arm or a leg, but not the trunk, there is an alternative. Since pain is transmitted by means of nerve fibres through the spinal cord, we can block the transmission of pain carried out by these nerve fibres if we lesion them at some point in the spinal cord. This is achieved by introducing a special needle, insulated completely except for the tip, which heats up when current is passed through it. It is this heat that burns the nerve fibres that transmit the pain, and so the opposite half of the body where this has been carried out will stop feeling pain. Unfortunately, this side of the body will also lose its sensitivity to temperature changes because the fibres that transmit pain, those that transmit the feeling of heat and those that transmit feeling of cold run together in the spinal cord.
Percutaneous thoracic cordotomy
WHAT WILL HAPPEN DURING A PERCUTANEOUS CORDOTOMY?
Admission into the hospital for 2-3 days before the procedure is recommended, especially if you are having the second side done (after having a cordomy performed on one side, a while back) or if a cervical cordotomy is to be carried out.
This procedure is usually performed in the neck, but may be applied anywhere else on the spinal cord, e.g. thoracic region if the pain affects one leg. Carrying out a cordotomy on both sides at a high cervical level is not recommended, for it can induce difficulties to breathe. This is why, when the cordotomy is to be bilateral, the cordotomy on each side is performed at a different level. If the pain affects one side, the procedure is carried out in the opposite side because the nerve fibres that transmit pain cross over to the opposite side as soon as they enter the spinal cord.
The skin of the area where the procedure is to be performed is first disinfected with iodine. Next, under local anesthesia, a thin needle is inserted into the part of the selected side of the neck closest to the head, and X-rays are used to check that it is exactly where it is intended to be.
Test electrical stimuli are then applied, and you will notice an electric current in some part of your body. The surgeon will need to know where you are noticing it, because the needle must be changed of position until the electric current is felt exactly in the area of pain. If this does not happen, the result of the procedure will not be good, and this is why it is so important that you convey to the surgeon exactly where you are feeling the current and where you feel the pain. The needle will then be exactly where it should be, and the technique will have maximum effectiveness.
Once the needle rightly positioned, a greater electric current is applied, warming the tip of the needle. The temperature that the tip reaches is controlled by a thermostat at the tip of the needle. It is this heat which will lesion the fibres that transmit pain, and depending on the temperature reached we can achieve a temporary or a permanent injury and a wider or smaller lesion. At the point in which the temperature is rising, the patient may notice some discomfort or even pain, but this is temporary.
Percutaneous cervical cordotomy
WHAT WILL HAPPEN AFTER THE PROCEDURE?
After the procedure you should spend a few days in the hospital, depending on the evolution and complications. The main problem is bladder control problems, especially in bilateral cases.
If there have been problems with bladder control, it may be necessary to leave an indwelling bladder catheter for a few days or to consult with the urologist.
If the long sections of the nerve fibres must be lesioned, a loss of strength on the side where the procedure has been performed, so the opposite side to that in which the pain has been eliminated, is possible. Usually this loss of strength is temporary and is recovered with rehabilitation.
In some cases there may be lack of balance for a while, mainly due to the lack of strength of one of the legs. This may last a few days or a few weeks, but disappears spontaneously in the majority of cases.
The chances of success are high, but, over time, the pain may return as the disease causing the pain progresses.
- After the treatment, the sensitivity to heat and cold is reduced on the side of the body when the pain was felt. After the treatment you must be careful when handling hot or cold objects or when having a hot shower. Always control the temperature with the “good” side of your body.
- Be careful too when handling sharp objects, such as potato peelers, for if you cut yourself you may not feel the pain.
- Walk with solid footwear both outside and inside of your house, for you may step on something and hurt yourself without feeling anything.