To conduct a systematic review of published research on the pharmacologic treatment
of pain after spinal cord injury (SCI).
MEDLINE, CINAHL, EMBASE, and PsycINFO databases were searched for articles published
1980 to June 2009 addressing the treatment of pain post SCI. Randomized controlled
trials (RCTs) were assessed for methodologic quality using the Physiotherapy Evidence
Database (PEDro) assessment scale, whereas non-RCTs were assessed by using the Downs
and Black (D&B) evaluation tool. A level of evidence was assigned to each intervention
by using a modified Sackett scale.
The review included RCTs and non-RCTs, which included prospective controlled trials,
cohort, case series, case-control, pre-post studies, and post studies. Case studies
were included only when there were no other studies found.
Data extracted included the PEDro or D&B score, the type of study, a brief summary
of intervention outcomes, the type of pain, the type of pain scale, and the study
Articles selected for this particular review evaluated different interventions in
the pharmacologic management of pain after SCI. Twenty-eight studies met inclusion
criteria; there were 21 randomized controlled trials; of these, 19 had level 1 evidence.
Treatments were divided into 5 categories: anticonvulsants, antidepressants, analgesics,
cannabinoids, and antispasticity medications.
Most studies did not specify participants' types of pain, making it difficult to identify
the type of pain being targeted by the treatment. Anticonvulsant and analgesic drugs
had the highest levels of evidence and were the drugs most often studied. Gabapentin
and pregabalin had strong evidence (5 level 1 RCTs) for effectiveness in treating
post-SCI neuropathic pain as did intravenous analgesics (lidocaine, ketamine, and
morphine), but the latter only had short-term benefits. Tricyclic antidepressants
only showed benefit for neuropathic pain in depressed persons. Intrathecal baclofen
reduced musculoskeletal pain associated with spasticity; however, there was conflicting
evidence for the reduction in neuropathic pain. Studies assessing the effectiveness
of opioids were limited and revealed only small benefits. Cannabinoids showed conflicting
evidence in improving spasticity-related pain. Clonidine and morphine when given together
had a significant synergistic neuropathic pain-relieving effect.