Intrathecal Baclofen Monotherapy and Polyanalgesia for Treating Chronic Pain in Patients with Severe Spasticity

Intrathecal drug delivery is a well evidenced strategy for the treatment of many chronic pain syndromes. While opioids, anesthetics, and ziconotide are the most commonly used agents, intrathecal baclofen (ITB), which is indicated to treat spasticity, is also thought to have some analgesic properties that are poorly understood. These analgesic benefits have been reported with ITB use in treating patients with central neurological disorders who suffer from severe spasticity and chronic pain. Our review aims to characterize ITB's effects on pain, function, and quality of life in patients with severe spasticity. We performed a systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. The primary outcome parameters were analgesic relief and functional improvements. Secondarily, quality of life and adverse effects were also recorded.

After an initial survey identified 393 studies, 20 studies met final inclusion criteria. Of these, 16 utilized ITB monotherapy and 4 utilized ITB polyanalgesia. Overall, there was a paucity of high-powered studies. Mean titrated ITB doses ranged from 140 to 627.9 μg daily. Nineteen studies reported improved pain and spasticity. Seven studies reported improved functional outcomes and quality of life. Our results show that ITB may be an effective agent in treatingfor the treatment of chronic pain in patients with severe spasticity independent of its spasmolytic effects. Although this evidence was largely derived from studies lacking clearly defined outcomes of pain relief, ITB is reasonable to consider for concurrent spasticity and pain management. Well-designed studies are still needed to characterize ITB's analgesic efficacy when used in patients with severe spasticity.