5.4.3 Neuroaugmentation
Interest in endogenous pain control systems as a therapeutic target began over
20 years ago in the context of the contemporaneous discoveries of the positive
reinforcing quality of electric self-stimulation of the brain in animals and
humans. Profound analgesia without drugs was reported in laboratory animals
during electrical stimulation of the brain stem (Reynolds, 1969; Yaksh and
Rudy, 1976). These effects appear to depend on the body's own opioids,
endorphins. Since then, electrical stimulation for cancer pain control has been
directed at deep brain structures such as the periaqueductal and
periventricular grey areas (Meyerson, Boethius, and Carlsson, 1978; Young and
Brechner, 1986), the limbic system (Gol, 1967), and other more superficial
sites such as the pituitary gland (Yanagida, Suwa, Trouwborst, et al., 1988).
Evaluation of the efficacy of electrical stimulation ("neuroaugmentation") of
deep brain structures for cancer pain relief, as for many other modalities, is
difficult because of scanty descriptions of patients' diagnoses and limited
pain assessment and followup, as well as the relatively few patients treated in
this fashion compared with much larger numbers treated, e.g., with
pharmacotherapy. Nonetheless, the few descriptive, uncontrolled published
studies report partial or complete pain relief in 27 to 76 percent of patients
treated by neuroaugmentation (Meglio and Cioni, 1982; Meyerson, 1982; Young and
Brechner, 1986). Published results of spinal cord stimulation for cancer pain
relief are less encouraging. Meglio and others (Meglio, Cioni, and Rossi, 1989)
reported, in a series of 109 patients treated for pain relief by means of
spinal cord stimulation, that none of the 11 who had cancer pain derived any
clinical benefit, in contrast to favorable responses observed in patients with
vasculopathic pain or postherpetic neuralgia. Similarly, others (North, 1993;
Gybels, 1993; Marchand, 1993) have found spinal cord stimulation useful to
treat chronic pain if not due to malignancy and only anecdotal observations
support the success of this modality in patients with cancer-related pain
(Miles, Lipton, Hayward, et al., 1974; Nittner, 1980; Raj, 1992).
TENS
Acupuncture
Introduction (Invasive nonpharmacologic interventions)
Plexopathy
Brachytherapy
Peripheral Neurectomy
Dorsal Rhizotomy
Surgical Management of Pain due to Primary or Metastatic Tumor
Index