Intrathecal drug infusion refers to the implantation of a special pump that is designed to release a specific medication (usually opioids, such as morphine) into the intrathecal space.
The intrathecal or Subarachnoid space is the area between the two layers of the spinal cord meninges—the arachnoid and the pia mater—where cerebrospinal fluid circulates. This continuous infusion results in altering or reducing the transmission of painful stimuli from the periphery to the brain, effectively relieving the patient’s symptoms.
The implantation of this pump is recommended for patients suffering from chronic somatic pain, which arises from dysfunction of tissues such as muscles, bones, and tendons (e.g., musculoskeletal pain), as well as for patients with chronic visceral pain, which originates from the dysfunction of internal organs like the pancreas, stomach, liver, etc. (e.g., cancer pain).
Since implementing the pump is an invasive procedure that is performed under general anesthesia ,it is typically suggested for patients who do not experience relief from the maximum safe oral dosage of medication or who suffer intolerable side effects from oral drugs. It is also indicated for patients who, for various reasons, cannot or do not wish to undergo surgery, or those who have undergone previous surgical or less invasive procedures that did not provide satisfactory symptom relief.
The entire procedure is done under general anesthesia. A small catheter is surgically placed into the intrathecal space and connected to the special pump that holds the medication. This pump is then implanted subcutaneously, typically under the fatty tissue of the abdominal area, making it invisible.
The pump contains all the necessary parameters for the treatment, including the dosage of the medication to be released, the infusion rate, meaning how frequently the medication is delivered. These parameters, if deemed necessary can be adjusted externally by the physician using a special device, without the need for any further invasive intervention.
Additionally, the patient is provided with a special remote control that allows them to release a small dose of medication on their own if they feel their pain is not adequately controlled. This self-administered “on-demand” dose is safe, as the pump’s settings, including the maximum number of doses that can be given per day, are pre-programmed by the physician, ensuring the patient cannot exceed safe limits and put themselves at risk.
