Flavonoids in the Treatment of Neuropathic Pain.

PURPOSE OF REVIEW: Chronic pain continues to present a large burden to the US healthcare system. Neuropathic pain, a common class of chronic pain, remains particularly difficult to treat despite extensive research efforts. Current pharmacologic regimens exert limited efficacy and wide, potentially dangerous side effect profiles. This review provides a comprehensive, preclinical evaluation of the literature regarding the role of flavonoids in the treatment of neuropathic pain. RECENT FINDINGS: Flavonoids are naturally occurring compounds, found in plants and various dietary sources, which may have potential benefit in neuropathic pain. Numerous animal-model studies have demonstrated this benefit, including reversal of hyperalgesia and allodynia. Flavonoids have also exhibited an anti-inflammatory effect relevant to neuropathic pain, as evidenced by the reduction in multiple pro-inflammatory mediators, such as TNF-α, NF-κB, IL-1ß, and IL-6. Flavonoids represent a potentially new treatment modality for neuropathic pain in preclinical models, though human clinical evidence is yet to be explored at this time.

Ultrasound-Guided Peripheral Nerve Stimulation of Cervical, Thoracic, and Lumbar Spinal Nerves for Dermatomal Pain: A Case Series.

OBJECTIVES: With the development of percutaneously inserted devices, peripheral nerve stimulation (PNS) has been gaining attention within chronic pain literature as a less invasive neurostimulation alternative to spinal column and dorsal root ganglion stimulation. A majority of current PNS literature focuses on targeting individual distal nerves to treat individual peripheral mononeuropathies, limiting its applications. This article discusses our experience treating dermatomal pain with neurostimulation without needing to access the epidural space by targeting the proximal spinal nerve with peripheral nerve stimulation under ultrasound-guidance. MATERIALS AND METHODS: A temporary, percutaneous PNS was used to target the proximal spinal nerve in 11 patients to treat various dermatomal pain syndromes in patients seen in an outpatient chronic pain clinic. Four patients received stimulation targeting the lumbar spinal nerves and seven patient received stimulation targeting the cervical or thoracic spinal nerves. RESULTS: The case series presents 11 cases of PNS of the proximal spinal nerve. Seven patients, including a majority of the patients with lumbar radiculopathy, had analgesia during PNS. Four patients, all of whom targeted the cervical or thoracic spinal nerves, did not receive analgesia from PNS. CONCLUSION: PNS of the proximal spinal nerve may be an effective modality to treat dermatomal pain in patients who are not candidates for other therapies that require access to the epidural space. This technique was used to successfully treat lumbar radiculopathy, post-herpetic neuralgia, and complex regional pain syndrome.

Pilot Study in Temporary Peripheral Nerve Stimulation in Oncologic Pain.

OBJECTIVES: Temporary, percutaneous peripheral nerve stimulation (PNS) has been shown to provide analgesia for acute postoperative pain, postamputation pain, and low back pain. The implanted device stimulates the neural target for up to 60 days at which point the leads are extracted. Patients have demonstrated prolonged analgesia continuing after extraction of the leads. The purpose of this case series is to demonstrate peripheral neural targets that could feasibly be used to treat various pain syndromes prevalent in the oncologic population. MATERIALS AND METHODS: A temporary, percutaneous PNS was implanted under ultrasound guidance in 12 oncologic chronic pain patients seen in an outpatient pain clinic who had failed medical and/or interventional management. The device was implanted for up to 60 days. Clinical progress of pain and functional capacity was monitored through regular clinical visits. RESULTS: The case series presents seven successful cases of implementation of the PNS to treat oncologic pain. Three of these cases demonstrate targeting of proximal spinal nerves to treat truncal neuropathic pain and lumbar radicular pain. The four remaining cases demonstrate successful targeting of other peripheral nerves and brachial plexus. We also share five failed cases without adequate pain relief with PNS. CONCLUSIONS: PNS has potential uses in the treatment of oncologic pain. Further high-quality studies should be designed to further elucidate use of the PNS to treat oncologic pain.