Pain Management in Neurogenic Thoracic Outlet Syndrome – Pharmacologic Strategies

Abstract

The diagnosis and management of thoracic outlet syndrome (TOS) is challenging and controversial. The symptoms seen in TOS patients depend on which structures are affected in the thoracic outlet. The most common form of TOS is the neurogenic TOS (NTOS), which frequently can cause neuropathic pain (NP). Treatment strategies for NTOS patients include minimally invasive therapies, muscle relaxants, anti-inflammatories and analgesics, trigger point injections or surgery. Treatment for NP will also include medications that target peripheral and central nerves or different cytokines affecting the sensitivity of sensory neurons to painful stimuli. The pharmacological treatment is challenging and patients often need to be treated with more than just one medication. Antidepressants, ­alpha-2-delta calcium-channel ligands, and topical lidocaine are considered as first-line treatments for NP in recent evidence-based recommendations. Tricyclic antidepressants (TCA) are established to be efficacious for several different types of NP and the antidepressant effect may be beneficial, because depression is a common concomitant disease in patients with chronic pain. Selective serotonin reuptake inhibitors are better tolerated than TCA’s, they are superior to placebo, but show only a weak ­analgetic effect. Anticonvulsants are a further important group. Carbamazepine, a sodium-channel blocker, has shown efficacy in the treatment of some forms of NP. Gabapentin is approved by the U.S. Food and Drug Administration for the treatment of postherpetic neuralgia (PHN). The pain relieving effects of pregabalin have been demonstrated in ­randomized controlled trials. Lidocaine patches are used as supplemental therapy. The benefits of opioids have been proven in RCT’s in central and peripheral NP. Pharmacological treatment of NP associated with TOS is challenging. Combination therapy appears useful and pain relief in NP patients is often achieved at the expense of unwanted systemic side effects. Clinical trials looking at pharmacological treatment of NP in patients with NTOS are lacking.