In preparation for a Tweetchat I am guest hosting on this topic for Pallimed, A Hospice and Palliative Medicine Blog (#hpm), I decided to put together this short summary of what neurosurgery has to offer for the palliative care of suffering patients. Links to references and other resources are at the bottom.
There are three major ways that neurosurgery can alleviate pain:
1. Targeted Drug Delivery in which medication is delivered directly to the brain or spinal cord by way of a very small catheter placed in the spinal fluid. The catheter could be connected to a pump placed under the skin for longer term use. Alternatively, a procedure not much bigger than a spinal tap can be used to place the catheter and bring it out through the skin to an external pump.
When patients require doses of opioids and other medications that give them unacceptable side-effects, like clouding of consciousness, lethargy, loss of appetite, severe constipation, targeted drug delivery can often allow caregivers to reduce or even eliminate such medications, resulting in an improved quality of life and often better pain control.
2. Neurostimulation is the use of electrical stimulation, through small electrodes placed via needle or small incision, to reduce pain. It is especially effective with neuropathic pain (the pain caused by an injured or damaged nerve that sends erroneous signals to the brain causing the perception of burning, itching ,swelling or other kinds of pain). One can stimulate a peripheral nerve, the spinal cord or even the brain (“deep brain stimulation”) to achieve pain control, depending on the circumstances.
Often neurostimulation is not considered in the context of palliative care. But, in such a setting, neuropathic pain can be difficult to address. It is possible to place a neurostimulation lead under the skin and bring it out to an external control (pulse generator). In this way, hard-to-control pain (e.g., after radiation, chemotherapy or the surgical injury of a nerve) can often be addressed without the additional incision and expense of an implanted pulse generator (as is used in non-palliative care settings).
3. Neuroablation is the interruption of certain pain pathways in the brain or spinal cord to achieve pain control. These can be very effective and often will allow the patient to drastically decrease or even eliminate the pain medication s/he is taking. There are a number of such procedures available, depending on the details of the pain. Percutaneous cordotomy, myelotomy and nucleotractotomy are outpatient, CT-guided procedures, done under local anesthesia through a needle, that interrupt the pain pathways for different locations. There are links to brochures below.
Cingulotomy is a procedure done under brief general anesthesia in which a computer is used to target two areas of the brain to interrupt pathways related to suffering. It can be very effective in treating the “suffering” component of pain. Recently, it was found to be effective in treating the air hunger associated with a lung tumor in a case report (see reference here).
Radiosurgical hypophesectomy is a non-invasive, single visit, outpatient procedure targeting the pituitary gland (hypophysis). It is based on decades of experience with surgically removing the pituitary gland for diffuse pain from bone metastases (cancer that has traveled to the bone). No one knows how it works, but it can be very effective. And, since it is completely non-invasive, the risks are very low. Even pituitary function is usually preserved and, if it is affected, hormones can easily be replaced.
References and Resources
A randomized, multicenter trial of targeted drug delivery for cancer pain – this does not, however, address an externalized catheter for palliative care
Intrathecal Drug Delivery for the Management of Cancer Pain: A Multidisciplinary Consensus of Best Clinical Practices
Here is a good review of neuroablation procedures: Destructive Procedures for the Control of Cancer Pain
A case series of radiosurgical hypophysectomy for cancer pain
Patient Resource is a great resource for cancer-related information. Their Cancer Guide has a good overview of pain control inside. In addition, the Cancer Pain Research Consortium is working with them to produce a guide to controlling cancer pain.(Disclosure: I am on their National Advisory Board.)