Implanting an infusion pump that continuously delivers the muscle relaxant baclofen to the spinal canal is a safe and effective treatment for muscle stiffness in people with neurological conditions, including cerebral palsy (CP), and provides a great degree of satisfaction to patients, according to 19 years of clinical experience at a single center in Portugal.
The results are detailed in the study “Intrathecal Baclofen Infusion Pumps in the Treatment of Spasticity: A Retrospective Cohort Study in a Portuguese Centre,” published in the journal Acta Médica Portuguesa.
Spasticity, the medical term for muscle stiffness, is a distressing problem for many patients with neurological disorders, including those with cerebral palsy. Stiff muscles can cause pain and discomfort and make movements difficult.
Directly infusing the muscle relaxant baclofen into the spinal canal (intrathecal infusions) is a treatment option to effectively reduce patients’ hyperactive reflexes and excessive muscle tone.
When taken orally, baclofen has difficulty crossing the blood-brain barrier — a selective membrane that shields the brain from the outside environment. As a result, delivering the medicine directly to the spinal canal instead has the potential to provide the same antispasticity effect at a much lower dose.
Intrathecal baclofen therapy (ITB), which uses a baclofen pump, enables the continuous delivery of the medicine to the cerebrospinal fluid, which is the fluid that surrounds the brain and spinal cord. Using a pump surgically implanted under the skin of the abdomen, the therapy employs a catheter — a thin, flexible tube — to bring the medication from the pump into the spinal fluid.
The baclofen is supplied by a reservoir connected to the catheter, which needs to be refilled from time to time. The device also contains a battery that may need periodic replacements.
Technological improvements have allowed ITB use in children, and there are studies supporting its safety in young children with cerebral palsy.
Usually, the lower doses of baclofen used for intrathecal delivery have minimal side effects. However, the procedure is not free of risks. Surgery-related complications, including infections or reopening of surgical cuts, failures in the pump, and human error — for example, overdosing — may lead patients to stop the treatment, or even, in rare cases, to death.
Now, a team of Portuguese researchers-physicians analyzed 19 years of medical records, up to 2015, from patients implanted with baclofen pumps at their hospital’s chronic pain unit (CPU). The goal was to evaluate the efficacy, incidences of complications, and patient satisfaction associated with the procedure.
During the 19-year period, a total of 251 baclofen pumps were placed in 155 patients, ages 7 to 77. Among the patents, 14 were younger than age 18. The most frequent conditions among the patients were trauma (34%), cerebral palsy (14%), multiple sclerosis (12%) and stroke (12%).
About half of the patients (55%) required a second pump, and 11 (7%) a third one. The first pump lasted a median of 6 years, with a range from 3 to 7.4 years. Median patient follow-up time was 8 years, with a range from 9 months to 11 years.
In the years covered by the study, 19% of the procedures had complications — 48 out of 251 surgeries — excluding battery replacements. Among the complications registered, infections accounted for 6.4% of the cases (16 events) and 9.6% were due to problems with the catheter (24 events).
Ten patients were lost to follow-up (6%) and 22 deaths were registered (14%), although none was related to the pumps. Overall, the incidence of complications and mortality was similar to other reports, despite this study’s longer follow-up time.
None of the patients experienced side effects directly caused by the intrathecal use of baclofen, or any neurological deficits tied to the treatment.
Pump removal or replacement resulted primarily from battery failure (57%), followed by catheter migration or kinking (24%), infection (14%), and pump displacement or exteriorization (7%).
Confirming prior reports, baclofen pumps proved effective for easing spasticity, as muscle tone and muscle spasm measurements among patients were seen to lessen considerably after the pumps were implanted.
Notably, all patients reported to be satisfied with the treatment. All confirmed improvements with the implant. Nearly half (44.6%) rated their quality of life and everyday activities as a level 10 on a rating scale from 0 to 10, with 0 being very unsatisfied and 10 totally satisfied.
“The results of this study demonstrate that IPs [intrathecal pumps] are a safe, valid and effective therapy in the treatment of spasticity,” the researchers said, adding that “infusion pumps provide a high level of satisfaction regarding treatment and quality of life.”
The researchers also note that ITB has high initial costs, yet its effectiveness and likely long-term benefits for the physical and mental well-being of patients end up making it a cost-efficient option.