Pump away shingles pain?

6 May, 2009 - A surgically implanted pump that delivers medication to the spinal fluid helps reduce the persistent pain that can linger in some patients after they recover from shingles, according to a new study.

‘All patients showed a greater than 50% improvement in pain control’, says Dr Andrew J. Fabiano, of the University of Buffalo in New York state who was scheduled to present the findings yesterday at the American Association of Neurological Surgeons meeting in San Diego. ‘The patients describe a dramatic improvement in pain’, he says. The study follow-up averaged nearly six years.

Shingles affects about one in five people in their lifetime according to the NHS, with the risk being much higher for people 50 and older.

Shingles occurs when the varicella zoster virus that causes chickenpox reactivates and causes a painful rash on the trunk or other parts of the body. In about 15% of patients, Fabiano says, the pain persists a month or longer, a condition called postherpetic neuralgia or post-shingles pain.

Shingles pain: Study details

Fabiano and his colleagues evaluated five patients - one woman and four men - all of whom had post-shingles pain. Their average age was 75 and none had been helped enough by the typically prescribed oral pain medications given for the condition.

They decided to study the pump system, already on the market and used for other chronic pain conditions, after finding little published on it for post-shingles pain.

They implanted a pump, which is about 8cm in diameter by about 3cm thick Fabiano says, in a procedure that takes about 45 minutes. The pump is placed under the skin, typically in the abdomen, and is attached to a small tube inserted into the spine. The medication goes from the pump through the tube and enters the spinal fluid.

Before the pump was implanted, all patients were given a trial, Fabiano says, either by injecting the pain medicine into the spinal area or placing a temporary catheter to deliver the medication for 24 or 48 hours to be sure the medicine worked for their pain.

The amount of medication delivered is pre-programmed and can't be changed by the patient, he says. The medicines delivered varied and included morphine with or without other medicines.

Fabiano acknowledges that the study is small and that they did not compare the patients with others not on the pump to determine the differences in pain relief. No outside sources funded the study.

The pump isn't for everyone, he says. ‘This is not a first-line treatment’, he says. ‘The first line is oral or transdermal [ skin patch] medication.’

‘It's for a minority of patients with shingles’, he adds. But for those whose pain doesn't respond to other treatments, he says, the pump is worth considering.

The patients didn't report any side effects.

Post-shingles pain: Pump is last report

Another expert agrees that the pump is a last resort for shingles patients in pain. ‘The ideal candidate is someone who has not been helped enough by other treatments who gets substantial pain relief from taking these opioid medicines by mouth but can't continue to do so because of severe side effects’, says Dr Anne Louise Oaklander, professor of neurology at Harvard Medical School, who reviewed the study results.

Those side effects include drowsiness and nausea, she says.

‘If oral [medicines] work fine’, she says, ‘stick with it.’