Intrathecal baclofen in multiple sclerosis and spinal cord injury: complications and long-term dosage evolution

To investigate the long-term dosage evolution and complication rate of intrathecal baclofen use in multiple sclerosis and spinal cord injury patients, based on a large population with a long follow-up.

Retrospective data analysis.

Academic hospital.

Patients with multiple sclerosis (n = 81) or spinal cord injury (n = 49) having an intrathecal baclofen pump implanted at the University Hospitals Leuven between 1988 and 2009.

Medical records review of included patients in August 2010.

Complications linked to intrathecal baclofen therapy. Daily baclofen dosage after 3 and 6 months, and yearly thereafter. Data on dosage evolution were analysed using a mixed-effect linear model.

In 130 patients with a mean follow-up of 63 months, comprising 797 pump years, 104 complications were recorded. This corresponds to a complication rate of 0.011 per month, equally divided among both groups. Seventy-eight of these complications were catheter related. The mean dosage of baclofen stabilizes two years after implantation at 323 µg/day in the multiple sclerosis population. In spinal cord injury patients the daily dose only stabilizes after five years at a significantly higher dosage (504 µg/day). No significant increase in dosage is seen in the long term.

In multiple sclerosis and spinal cord injury patients, intrathecal baclofen therapy has a complication rate of 1% per month. Complications are mainly due to catheter-related problems (74%). The intrathecal baclofen dosage stabilizes in the long term, indicating that long-term tolerance, defined as progressive diminution of the susceptibility to the effects of a drug, is not present.