A certain category of patients are suffering from widespread pains of a very severe nature. Usually these patients suffer from malignant diseases and have pains arising from bone metastases, distension, compression or irritation to nerves or organs. Since the pains are arising from multiple sources, isolated lesioning or neuromodulatory techniques are usually not effective and need opioids (narcotics) in high doses which have many side effects. Constipation, respiratory depression, itching and an altered state of mind are among the most common adverse effects. In such patients who have a longer expectancy of life are encouraged to have an intrathecal drug delivery system implanted in them. The advantages of such a system are that the opioid dose is reduced by approximately ten times and with better pain control.
These systems consist of a tiny implantable device that is placed in a superficial skin pocket and cosist of a programmable reservoir for the drug to be delivered at a constant rate and have a refillable percutaneous port for refilling. They can be programmed from outside only and one can increase or decrease the delivery rate of the drug dose. Similar pumps are also useful in spastic patients having generalized symptoms and needing quite a high oral or parentral dose of baclofen (anti spatic drug most commonly used). Delivering baclofen or morphine within the cerebrospinal fluid increases their efficacy as well as reduces the overall dose with substantial reduction in adverse effect profile. Another advantage of these systems is their continuous supply of the drug at a constant and uniform rate. This provides a near normal blood level throughout 24 hours with minimal fluctuation. Newer systems are being developed that sense the need of the patient and can then vary the delivered drug based on the patients’ requirement.