Peripheral Nerve Injuries

The part of the peripheral nervous system that carries sensory information to the CNS is designated

Studies on nerve fibers’ longitudinal growth, axons’ regeneration and structural plasticity of axons and dendrites illustrated that they are restricted to short distances and limited spatial dimensions in the CNS. Scientists recognized that neural repair required plasticity, sprouting, and regeneration, which was limited within the adult CNS. However, once adult CNS axons from multiple areas successfully regenerated into peripheral nerve grafts in the spinal cord, brain, or optic nerve, scientists discovered the key role of local tissue microenvironment in determining the extent of growth. Scientists discovered neurite growth inhibitor factors enriched in myelin such as Nogo-A, myelin proteins, MAG and OMgp, semaphorins and ephrins, and chondroitin sulphate

found that motor unit twitch force remains constant or is even slightly increased following chronic denervation, challenging the theory that denervated muscle cannot be re-innervated, as believed since the findings of Gutmann. (Gutmann 1948, Fu and Gordon 1995a) Compensatory enlargement through the incorporation of denervated muscle fibers into adjacent motor units, by collateral sprouting, can make up for a loss of up to 80% of motoneurons of a muscle, as motor unit expand their size 3 to 5 fold. (Gordon, Yang et al. 1993) After 6 months of denervation maximal motor unit expansion through collateral sprouting was found, even though functional recovery was poor. (Fu and Gordon 1995b) These findings demonstrate that both the reduced number of axons reaching denervated motor endplates and atrophic muscle changes, respectively, influence poor functional outcomes after nerve injury. (Fu and Gordon 1997, Furey, Midha et al.

The CNS contains the brain and spinal cord. Its main functions include: processing, integrating, and coordinating sensory information and motor instructions. The sensory data conducts information that is being processed from internal and external conditions the body is experiencing. Motor commands regulate and control peripheral organs (skeletal muscles). The brain functions under memory, emotions, learning, and intelligence. The PNS consist of the neural tissue found outside of the CNS. It functions in sending data to the CNS which motor commands are than carried out to the peripheral tissues/systems. Multiple nerve fibers send sensory data and motor commands in the PNS. The nerves that assist with transmitting data include the cranial nerves and spinal nerve. However, the PNS can be divided into afferent (to bring in) and efferent (to bring out) divisions of transferring data. The afferent division functions in bringing in sensory data to the CNS. Sensory structures are receptors that detect internal/external environmental change and adjusting accordingly. The efferent division functions in carrying out motor commands from the CNS to glands, muscles, and adipose tissue. The efferent division contains somatic

Evaluation of the prognosis of recovery of the nerve injury should be first established before management could be done conservatively or using a surgical approach.

A spinal cord injury does not occur in a single moment. Instead damage will continue to ensue for days to weeks after the initial injury. The initial impact and injury causes the immediate damage and death of oligodendrocytes and motor neurons. However, another wave of damage is caused by the secondary processes that occur after the injury. The spinal cord is a bundle of nervous tissue and neurons protected by the vertebral column that transmits electrical synapses, or messages, from the brain to the rest of the body. It is composed of three layers of membranes and is protected by the bony vertebrae that make up our vertebral column. The spinal cord upon impact will swell and secrete chemicals which will cause an inflammatory response and will kill neighboring cells increasing the amount of functioning lost throughout the body. The swelling can also cut off the blood flow to the

The muscular system, in conjunction with the skeletal system, is responsible for movement of the body among other things (VanPutte, 270). The ability of the human body to move has been critical in the survival of the species over the years—for example; escaping from predators is only possible with skeletal muscle contraction. Hansen’s disease generally only affects the peripheral nerves of the extremities, not the locations of the larger muscle groups; however the smaller muscles of the hands and feet are vital for the well-being of individuals. For example, it would be quite difficult to feed oneself without the use of hands. Unfortunately, extreme cases of Hansen’s disease cause paralysis of the individual’s hands and feet. Paralysis occurs due to deadening of the peripheral nerves, both sensory and motor. As the afferent neurons lose the ability to receive and send stimuli, the nerve impulses (action potentials) are sent to the central nervous system less and less often. Even so, the action potentials that are transmitted to the CNS still are unlikely to stimulate the skeletal muscles for contraction. This is because the efferent peripheral neurons of the hands and feet are damaged as well. In effect, the sensory nerves of the extremities cannot receive much stimuli, and the motor neurons are also less able to start the action potentials in the skeletal muscle

Out of the twelve cranial nerves, I picked the optic nerve to research on how it can become damaged. Optic nerve damage would be described as any kind of injury or damage to the optic nerve, which is including trauma, inflammation, disease or deterioration. There is another name for optic nerve damage, which is called optic nerve atrophy or optic neuropathy. Optic nerve damage involves vision damage, vision loss, and blindness. Optic nerve damage can result from a various of different things. It can form from Glaucoma, or also known as high blood pressure within the eye, an infection or inflammation, interruption in blood circulation to the optic nerve, cancer, and trauma.

Based on the literature the use of indwelling electrical stimulation after injury and surgical repair is supported as a modality to promote axonal regeneration of both sensory and motor neurons in animals and humans. The stimulation protocol that is seen as being the most beneficial for axonal regeneration and functional recovery is brief, low frequency (20Hz) continuous electrical stimulation with short phase duration and between 3-5 volts. Asensio-Pinilla et al. looked that the effects of electrical stimulation combined with exercise to increase axonal regeneration. Treadmill training when combined with acute electrical stimulation was seen to enhance regeneration and increase motor nerve conduction velocity. Asensio-Pinilla et al. was able to provided

The nerve did not likely have a complete laceration, but rather her post-surgical issues may have been a result of a stretching injury or adjacent soft tissue swelling which could resolve

It is known that following primary sensory axonal injury there is a slight increase in regeneration of their central axons, meaning that the increase in growth status after injury causes regeneration. Previous studies have looked into conditioning lesion and found that primary sensory neurons can in fact increase their growth capacity and enhance regeneration after injury, activating ciliary neurotrophic factors (CNTF), interleukin-6 (IL-6), and the cAMP signaling pathway among others in conditioning lesion. In the current article the researchers investigated whether ATP injection into peripheral nerves were able to mimic the effects of nerve injury in promoting regeneration of sensory neurons both in vivo and in vitro, so that the growth and

Stretch-related injuries, compression, ischemia and lacerations are among the most common peripheral nerve injuries (Burnett). The severity and the amount of disruption to internal structures of the nerve determine the degree of injury. There are five degrees of injury that exist ranging from first to fifth degree based on the Sunderland classification system (Burnett). A first-degree injury is the least severe and a fifth-degree injury is the most severe resulting in complete transection of the nerve. The degeneration and regeneration process of peripheral nerves is depended on the degree of injury and axon length to target muscle (Campbell). Since injury by way of laceration is easily reproduced, research subjects in the literature analyzed

Objective: Facial nerve injury is considered as the most frequent complication of parotid gland surgery due to close relation of the extra-temporal course of facial nerve and the parotid gland. The aim of the current study was to evaluate the role of anatomical location of parotid tumors in the incidence of post-operative facial nerve paresis with antegrade dissection technique. Methods: Patients with parotid tumors required surgical procedures were enrolled in the study. Preoperative evaluation of the tumor location within the parotid gland tumor was done using axial and coronal CT. Transient facial nerve dysfunction was investigated in relation to the following factors: patient age, tumor size, histopathological diagnosis, and the location

The peripheral nervous system (PNS) is connected directly to the central nervous system, and consists of neurons and nerves that send information back and forth the CNS. Furthermore, the peripheral nervous system can be divided into two sections, the sensory nervous system and the motor nervous system. The Sensory The sensory nervous system is in charge of transmitting data from a variety of internal organs or from external stimuli to the central nervous system using sensory nervous cells. On the other hand, the cells of the motor nervous system (motor neurons), take the impulse from the CNS to effectors, which include glands and muscles. In addition, the motor nervous system can be further divided into the somatic nervous system, controls voluntary actions of the skeletal muscle and external sensory organs, whilst the autonomic nervous system operates

The two systems within the peripheral nervous system are somatic nervous system and the central nervous system. The control that somatic nervous system have is the process of reflex arcs and optional muscular systems. The peripheral nerve sends sensory information that predict skeletal muscles to the motor nerve and central nervous.