Pathophysiology Of Nerve Injury Research Articles

The Importance of Rare Subtypes in Diagnosis and Treatment of Peripheral Neuropathy: A Review.

Peripheral neuropathy is a prevalent condition that usually warrants a thorough history and examination but has limited diagnostic evaluation. However, rare localizations of peripheral neuropathy often require more extensive diagnostic testing and different treatments. To describe rare localizations of peripheral neuropathy, including the appropriate diagnostic evaluation and available treatments. References were identified from PubMed searches conducted on May 29, 2015, with an emphasis on systematic reviews and randomized clinical trials. Articles were also identified through the use of the authors' own files. Search terms included common rare neuropathy localizations and their causes, as well as epidemiology, pathophysiology, diagnosis, and treatment. Diffuse, nonlength-dependent neuropathies, multiple mononeuropathies, polyradiculopathies, plexopathies, and radiculoplexus neuropathies are rare peripheral neuropathy localizations that often require extensive diagnostic testing. Atypical neuropathy features, such as acute/subacute onset, asymmetry, and/or motor predominant signs, are frequently present. The most common diffuse, nonlength-dependent neuropathies are Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and amyotrophic lateral sclerosis. Effective disease-modifying therapies exist for many diffuse, nonlength-dependent neuropathies including Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and some paraprotein-associated demyelinating neuropathies. Vasculitic neuropathy (multiple mononeuropathy) also has efficacious treatment options, but definitive evidence of a treatment effect for IgM anti-MAG neuropathy and diabetic amyotrophy (radiculoplexus neuropathy) is lacking. Recognition of rare localizations of peripheral neuropathy is essential given the implications for diagnostic testing and treatment. Electrodiagnostic studies are an important early step in the diagnostic evaluation and provide information on the localization and pathophysiology of nerve injury.

Peripheral nerve injury grading simplified on MR neurography: As referenced to Seddon and Sunderland classifications.

The Seddon and Sunderland classifications have been used by physicians for peripheral nerve injury grading and treatment. While Seddon classification is simpler to follow and more relevant to electrophysiologists, the Sunderland grading is more often used by surgeons to decide when and how to intervene. With increasing availability of high-resolution and high soft-tissue contrast imaging provided by MR neurography, the surgical treatment can be guided following the above-described grading systems. The article discusses peripheral nerve anatomy, pathophysiology of nerve injury, traditional grading systems for classifying the severity of nerve injury, and the role of MR neurography in this domain, with respective clinical and surgical correlations, as one follows the anatomic paths of various nerve injury grading systems.

Ion Channel Targets and Treatment Efficacy in Neuropathic Pain

Chronic neuropathic pain due to injury or dysfunction of the nervous system remains a formidable treatment challenge in spite of a growing range of medication choices. We review current clinical research supporting the use of ion channel modulators for neuropathic pain states. New modes of local drug delivery, novel Ca 2+ channel targets, and increased choices for drugs with activity at Na +channels are transforming this longstanding therapeutic strategy. Clinical decision making is increasingly informed by a more nuanced understanding of the role of voltage-gated Na +channels (VGSCs) and Ca 2+ channels (VGCCs) in the pathophysiology of nerve injury. Although holding great promise for the future, mechanism-based approaches to treatment will require greater understanding of the analgesic mechanisms of drug action and of the relationships between pathophysiologic mechanisms and clinical presentation. Perspective Treatment options for neuropathic pain targeting ion channels have grown rapidly in the past decade. An evolving body of clinical research supports the widespread use of this longstanding therapeutic strategy. Improved efficacy of ion channel modulators hinges upon further elucidation of the relationship between signs and symptoms of pain and underlying pathophysiology.

Evaluation and Surgical Repair of Brachial Plexus Injuries

Traumatic injuries of the brachial plexus may result in severe and permanent loss of motor and sensory function of the involved extremity. The neurosurgeon's ability to improve the functional outcome following a plexus injury requires an understanding of the functional anatomy of the brachial plexus, the pathophysiology of nerve injury, and the natural history of these lesions. Primary reanastomosis, neurolysis, and nerve grafting techniques are commonly used to restore normal axonal continuity. When these options are unavailable, muscle and tendon transfers or neurotization techniques have been successful in achieving functional restoration of limb movements.

TECHNIQUES FOR PRIMARY NERVE REPAIR

This article reviews the anatomy of the peripheral nerve, the pathophysiology of nerve injury, and Wallerian degeneration. It reviews the factors for deciding on immediate or delayed primary nerve repair and discusses the concept of longitudinal excursion of peripheral nerves about joints and the techniques for achieving an appropriate tension-free repair. The techniques of primary nerve repair, epineurial repair, and group fascicular repair are reviewed along with techniques for matching fascicles intraoperatively.

Quantitative sensory testing in pain states

The diagnosis and treatment of chronic pain presents a constant challenge for practicing physicians.There are numerous disorders of the peripheral and central nervous system that lead to chronic pain states.The pathophysiology of nerve injury in chronic pain states is highly complex and therefore leads to unpredictable response to treatment modalities. Standard diagnostic tools are often inadequate or equivocal in these conditions. Physical examination on the other hand is prone to examiner bias. Quantitative sensory testing of the nociceptive system consists of psychophysical methods used to measure intensity of stimuli needed to produce specific sensory perceptions. Measurements of subjective thresholds to thermal, mechanical, and electrical stimulation reflect the state of the peripheral and central nervous system responsible for pain processing.As opposed to standard diagnostic tools, quantitative sensory testing enables us to test specific components of the nociceptive system (such as unmyelinated C-fibers). In the clinical setting, quantitative sensory testing is becoming a clinical standard for evaluation of certain chronic pain conditions. Further clinical trials might enable us to use quantitative sensory testing as guidance for tailoring a therapeutic approach.