LAS VEGAS—Compared with conventional medical management, intrathecal baclofen significantly improves poststroke spasticity, according to research presented at the 21st Annual Meeting of the North American Neuromodulation Society. Intrathecal baclofen also appears to improve functional independence and reduce pain, compared with standard treatment.
“This was the first randomized, controlled trial comparing intrathecal baclofen and conventional medical management in a poststroke patient population,” said Michael J. Creamer, DO, a pain medicine specialist at Central Florida Pain Relief Centers in Orlando. The results may “provide additional options to stroke survivors and their families,” he added.
The SISTERS Trial
The prevalence of poststroke spasticity is estimated to be as high as 43%. Approximately 70% of stroke survivors with spasticity and their caregivers rank spasticity as one of the top three symptoms that affect their lives. Treatments for managing poststroke spasticity include physical therapy, occupational therapy, oral antispasmodic agents, intrathecal baclofen, and botulinum toxin.
Dr. Creamer and colleagues conducted the Spasticity in Stroke Randomized Study (SISTERS) to compare the effect of an intrathecal baclofen pump on poststroke spasticity with that of conventional medical management. The study used the Medtronic SynchroMed II Infusion System to deliver Lioresal Intrathecal (baclofen). The investigators also sought to analyze the pump’s effects on function and pain. They conducted the open-label, phase IV study at 11 centers in Europe and seven in the United States.
Eligible participants had a prior cerebrovascular accident, had substantial upper- and lower-limb spasticity (ie, an Ashworth Scale score of 3 or higher in at least two muscle groups of the lower extremity), had failed prior treatment, and had significant functional limitations. Patients were randomized to an intrathecal baclofen trial or a continuation of oral antispasmodic agents. Patients who successfully completed the baclofen trial underwent pump implantation. Both study groups received physical therapy. At regular visits, investigators measured participants’ spasticity and pain and monitored participants for functional improvements and adverse effects.
The primary outcome was change in Ashworth Scale in the lower extremities from baseline to six months. Secondary outcomes included change in upper-limb spasticity, functional independence, and pain.
Implanted Patients Had More Adverse Events
Dr. Creamer and colleagues randomized 60 patients, and 25 patients underwent intrathecal baclofen pump implantation. A total of 48 patients completed the study, 24 in each treatment arm. Demographic characteristics were similar between groups. The population was predominantly young (mean age, 56) and male (70%). Mean poststroke spasticity duration was approximately four years at enrollment.
Mean reduction in Ashworth Scale score was 0.99 points for patients who received intrathecal baclofen, compared with 0.43 points for those who received conventional medical management. The researchers saw no correlation between catheter tip placement and successful reduction of upper-limb spasticity.
The researchers observed a trend toward improvement in Functional Independence Measure score for patients who underwent pump implantation, but the data did not reach statistical significance.The rate of satisfaction with the pump was high among implanted patients.
In addition, Dr. Creamer and colleagues recorded statistically significant reductions in Numeric Pain Rating Scale scores for actual pain and least pain. Scores for worst pain also improved, but the result was not statistically significant.
The rate of adverse events was higher in the intrathecal baclofen group (96%) than in the conventional medical management group (63%). Adverse events in the former group generally were consistent with the known safety profile of intrathecal baclofen therapy. All serious adverse events related to the drug or device were resolved by the conclusion of the study.
The study’s strengths include its randomized, controlled design and objective spasticity measurements. One limitation, however, is that the sample size was lower than anticipated because of recruitment difficulties. Furthermore, the study was not powered to detect treatment differences for secondary outcomes. Finally, the six-month follow-up period was relatively short, said Dr. Creamer.
Creamer M, Cloud G, Kossmehl P, et al. Intrathecal baclofen therapy versus conventional medical management for severe poststroke spasticity: results from a multicentre, randomised, controlled, open-label trial (SISTERS). J Neurol Neurosurg Psychiatry. 2018 Jan 11 [Epub ahead of print].