RESUMO
Headache is a leading cause of disability and suffering. One major challenge in developing device treatments is demonstrating their efficacy given devices' often-high placebo rate. This paper reviews the importance of validating sham devices as part of finalizing the design for larger-scale prospective randomized controlled trials in patients with chronic headache as well as the results of a prospective, single-blind trial to validate two potential sham noninvasive thermal nerve block devices. Study participants were trained to self-administer thermal nerve block treatment using sham devices in an office visit. Two different sham systems with different temperature profiles were assessed. Devices were offered for patients to use daily at-home for one week to assess the durability of sham placebo effects before participants were given active treatment in a second office visit followed by another optional week of self-administered active treatment at-home use. Sham treatments reduced pain scores by an average of 31% from 6.0 ± 2.3 to 4.3 ± 3.3, including two participants who fell asleep during the in-office treatment and woke up with no pain, but whose pain recurred after returning home during at-home use of the sham system. In-office active treatments reduced pain scores by 52% from 6.7 ± 2.1 to 3.3 ± 2.9 with sustained pain relief during optional at-home use. Successful blinding for the study was confirmed with an ideal Bang's Blinding Index of 0 and an ideal James' Blinding Index of 1. Both the sham and active treatments were viewed by participants as highly credible, and credibility increased from the beginning to end of sham treatments on average.
RESUMO
BACKGROUND: Trigeminal neuralgia (TN) is a chronic neuropathic pain condition affecting one or more divisions of the fifth cranial (trigeminal) nerve. TN is defined by recurrent unilateral electric shock-like pain that is abrupt in both onset and termination. The pain is triggered by innocuous sensory stimuli and is classified as either classic TN, related to vascular compression; secondary TN, due to a tumor along the trigeminal nerve or an underlying disease like multiple sclerosis; or idiopathic TN. Among the various therapies available for TN, carbamazepine remains the first-line treatment. Newer medications have demonstrated efficacy in patients who do not respond to or cannot tolerate carbamazepine. When medical management and neuroablative procedures fail, spinal cord stimulation (SCS) serves as a promising and popular option, with an estimated 34,000 SCS procedures performed annually worldwide. SCS employs the implantation of electrical leads in the epidural space to manage pain. PURPOSE OF REVIEW: A review of literature was conducted to explore the use of cervical spinal cord stimulation (SCS) for the treatment of trigeminal neuralgia. METHODS: A MEDLINE/PubMed search using the search terms "spinal cord stimulation" and "trigeminal neuralgia" was employed to find any case reports and research studies (retrospective studies, double-blinded studies, observational studies) on the topic. No date limiters were used for the search. The initial search resulted in 76 non-duplicate entries from the database. After application of the search criteria, 58 studies were excluded because they were not relevant to the study. A further detailed review of the included articles was conducted by all the reviewers. During this phase of the review, additional 6 studies were excluded. A total of 11 studies were included: 7 case reports and 4 retrospective review studies. RECENT FINDINGS: In the review, we discuss 7 different case reports on the use of cervical SCS for trigeminal neuralgia and an additional 4 retrospective studies reviewing outcomes and pain relief in patients who underwent treatment. The case reports and retrospective studies reviewed demonstrated that TN patients realized > 50% pain relief following permanent electrode implantation. In all the cases discussed, complications from SCS were rare and/or not reported. Additionally, most of the cases report that patients who had adequate pain relief from SCS were able to wean off, or significantly reduce, oral medications given the vast improvement in pain reduction. CONCLUSIONS: Cervical spinal cord stimulation (SCS) is a safe and effective procedure for patients with trigeminal neuralgia (TN) who have refractory pain despite the use of medications. In many cases, the procedure provides an adequate level of pain relief with very few complications or side effects. The vast majority of current research on the use of cervical SCS for TN currently consists of case reports and retrospective analysis. In order to further evaluate the efficacy of SCS for treatment, large-scale randomized controlled studies or observational studies need to be conducted to properly evaluate SCS as a treatment modality for trigeminal neuralgia.
