2/18/20 Peripheral Tambra Marik, OTR/L, OTD, CHT Nerves Medical University of South Carolina South Carolina Occupational Therapy Association Marc Bartholdi, OTR/L, OTD, CHT February 29, 2020 Select Medical 1 South Carolina Occupational Therapy Association Annual Conference 2020 Tambra Marik, OTD, OTR/L, CHT Peripheral Assistant Professor Medical University of Nerve Injuries South Carolina Marc Bartholdi, OTR/L, OTD, CHT Select Medical 2/28/20 2 Objectives • Discuss the basic anatomy and physiology of the nervous system • Identify varying surgical techniques for common nerve compression injuries • Apply assessment tools to evaluate peripheral nerve compression • Apply evidence-based intervention to treatment of common nerve compression conditions • Identify common brachial plexus injuries • Analyze proximal nerve symptoms to guide with treatment • Demonstrate cervical screening to rule in/out spinal nerve root injury • Implement treatment strategies for cervical nerve root compression • Evaluate and implement therapeutic techniques for Thoracic Outlet (TOS) 3 1 2/18/20 The Nervous System Structurally Functionally • Somatic Nervous System • Central Nervous System • Voluntary: Sensory carries (CNS) sensations and position sense • Brain and spinal cord from skin and joints. Motor carries impulses to muscles • Peripheral Nervous System (PNS) • Autonomic Nervous System • Involuntary/visceral: walls of • Nerve fibers and cell bodies blood vessels, sweat glands, viscera (internal organs), body cavities (heart, stomach, bladder, etc) By Own work, CC BY 3.0, https:/ /commons.wikimedia.org/w/index.php?curid=10187018 By OpenStax College - Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013., CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=301480084 4 Central Nervous Structure: Brain & Spinal Cord System (CNS) Function: Control Center & Integrative Peripheral Structure: Cranial & Spinal Nerves Nervous System Function: Communicates between CNS and (PNS) the rest of the body Autonomic Involuntary/Visceral Sensory Motor Structure: Somatic & visceral Structure: Motor nerve Sympathetic: Parasympathetic: fibers fiber Fight or flight Conserves Energy Function: Connects impulses Function: Conducts from receptors to the CNS impulses from CNS to muscles & glands 5 Spinal cord relays information to and from the brain through the spinal tracts through the thalamus and finally to the cortex. Dorsal Horn Sensory Ventral Horn Motor By OpenStax College - Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, https://upload.wikimedia.org/wikipedia/commons/f/f3/Sobo_1909_615.png Jun 19, 2013., CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=30148131 6 6 2 2/18/20 Peripheral Nerve Axon away • Peripheral nerves connect information to the central nervous system • Consist of cell body, dendrite send messages to cell body and axon send Dendrite receives messages message out https://upload.wikimedia.org/wikipedia/commons/1/10/Blausen_0657_MultipolarNeuron.png • Efferent: motor • Afferent: sensory • Interneurons: connect neurons within a specific region (sensory or motor) to the central nervous system. Play a role in Interneuron By By Ruth Lawson Otago Polytechnic - originally uploaded at en.wikibooks. original description reflexes. page is/was here[1], CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=8831185 7 7 Spinal Nerves Mixed Fibers Part of Peripheral Nervous System • 8 pairs of cervical nerves • 12 pairs of thoracic nerves • 5 pairs of lumbar nerves • 5 pairs of sacral nerves • 1 pair of coccygeal nerves 8 • Axons: receives information • Dendrite: relays information dendrite • All peripheral nerve fibers have a sheath cell and a soma Schwann cells. Larger nerve fibers have a fatty (myelin) sheath in addition to the Schwann cell • Presence of myelin speeds conduction Myelin sheath • Nodes of Ranvier: constrictions separating successive Node of Ranvier segments Schwann of myelin cell • Nerve impulses “leap” from node to node • Farther apart=faster conduction Axon terminal Attribution: Quasar Jarosz 9 9 3 2/18/20 Peripheral Nerve Communication • Nerves have three connective tissue layers to protect • Endoneurium: inner most nerve fiber or axons; protects against transmission of substances across the membrane • Perineurium: surrounds fasicles of nerve axons controls substances bi-directionally, diffusion barrier • Epinueurium: outer most connective tissue that is highly vascularized 10 10 Sensory Receptors • Mechanoreceptors/Pressure, Proprioception • Meissner corpuscles: light touch • Merkel cells: light touch (abundant in fingertips) • Ruffini (Bulbous Corpuscle): skin stretch, temperature, contribute to proprioception • Pacinian corpuscle: vibrations • Free nerve endings: pain fast adapting (A delta II) slow adapting (A delta I and C fibers) http://www.bayareapainmedical.com/nerve.html 11 Sensory Receptors of Muscle & Tendon • Muscle Spindles : detect changes in length, protects muscle length with the stretch reflex. • Golgi tendon reflex (inhibitory): detects muscle tension changes, protects muscle force to help maintain steady levels of tension and stable Joints to counteract effects that reduce muscle force such as fatigue 12 4 2/18/20 Nerve Injury Classification Mononeuropathy Poly Neuropathy • Traumatic or non-traumatic • Metabolic • Compression syndromes • Nutritional • Can result in ischemic changes, edema injury • Hereditary to myelin • Immunologically Mediated • Can result in demyelination, axonal degeneration, or both • Infectious Disease • Nerve lacerations/compression • Neoplastic • Motor & Sensory Deficits in nerve distribution • Bilateral & Symmetrical • Weakness is dependent on the motor units • Affects large fibers distally first damaged • Sensory loss precedes motor loss • Sensory loss is distal to injury site • Sensory loss at feet followed by hands (bilateral) 13 13 Peripheral Nerve Injury • Macrophages and phagocyte remove myelin and axonal debris. Schwann cells signal to turn on pro-growth genes. • The proximal end forms a growth cone that secretes growth hormone to be guided back to its target nerve if the cell body is intact and Schwann cells have made contact in the endoneurial tube • Schwann cells then proliferate and migrate to regenerating axon Photo from: Arslantunali, D., Dursun, T., Yucel, D., Hasirci, N., & Hasirci, V. (2014). Peripheral nerve conduits: technology update. Medical Devices (Auckland, NZ), 7, 405. 14 14 Nerve Injury Seddon Classification Seddon Peripheral Nerve Injury Classification (Sunderland not on chart) Axonotomesis Photo by Syedm191 - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=58517905 Seddon Axon Endoneural Peri- Epi- Wallarian Nerve conduction 1943 Tube neurium neurium Degeneration distal to injury/Prognosis Neuro- + + + + No Present/ praxia Reversable Axono- - +/- ? + + Yes Absent/ tomesis Reversable Neuro- - - - +/- ? Yes Absent/ tomesis Irreversible 15 5 2/18/20 Nerve Injury Classification Sunderland 16 Medical Treatment • Neurapraxia - Observation • Axonotmesis - Surgical intervention may be required • Neurotmesis - Loss of nerve trunk, surgical intervention necessary. 17 Nerve Mechano-sensitivity Proximal Injuries Referring Distally Sensitivity of Regenerating Axon Sprouts • Micro-neuromas (sprouting nerve cells) form around the damage nerve • New cells fire causing severe electrical burning and shooting pain http://www.bayareapainmedical.com/nrvp ain2.html 18 6 2/18/20 Nerve Mechano-sensitivity Proximal Injuries Referring Distally Nervi Nervorum (unmyelinated or poorly myelinated fibers in peripheral nerve sheaths) • Participate in the transmission of evoked sensory information • Neuropeptide release leading to edema due to poor lymphatic drainage. Distorts the endoneurom and epineurom due to Image from: Lam, K. H. S., Hung, C. Y., Chiang, Y. P., Onishi, K., Clark, T. B., Reeves, D. K., & Daniel, S. (2020). Ultrasound-Guided Nerve Hydrodissection for Pain Management: An Updated Review of Anatomy and Techniques. pressure. • Inflammatory mediators spread distal likely related to poor lymphatic drainage • Nerve becomes more sensitive 19 Histopathology of Chronic Nerve Compression 20 Double Crush Syndrome Axioplasmatic Flow Disruption Alterations of Axoplasmic Flow • Possible alterations with a proximal lesion affecting distal compression sites • Possible alterations with a distal lesion affecting proximal lesion sites • Alterations to neural transmission (axoplasmic flow), but each site in isolation may not reproduce patient symptoms when tested (Hurst, Weissberg & Carroll, 1985) 21 7 2/18/20 Double Crush Syndrome Possible Posture Contribution (cont.) ↑ Muscle ↓ Muscle Length Length Middle traps. Sternocleidomastoid Lower traps. Serratus anterior Pronator teres Scalenes ↑ Nerve Pectoralis minor Tension/Compres- sion Carpal tunnel Muscle Weakness Muscle Overuse Cubital tunnel Middle trapezius Upper trapezius Levator scapulae Median nerve Lower trapezius forearm Serratus anterior Radial sensory Novak & Mackinnon, 2005 Brachial plexus • Movement patterns and posture can be effected with a nerve compression • Muscle imbalances can occur 22 Thoracic Outlet (TOS) Potential Compression Sites • Interscalene triangle Anterior and middle scalenes • Costoclavicular space Between clavicle and 1st rib • Thoraco-coraco-pectoral space Pectoralis minor neural, arterial and/or venous Photo from: Jones, M. R., Prabhakar, A., Viswanath, O., Urits, I., Green, J. B., Kendrick, J. B., ..