With Seddon's classification of nerve injuries, it is often tough to identify whether a particular nerve injury is<unk> , or axonotmesis, which has damage to the nerve fibres but preservation of the nerve trunk. Due to the damage involved in both of these conditions they will both show paralysis of muscles that are supplied by nerves below the site of the lesion, and will have sensory deficits in accordance with the individual nerves that are damaged. The only way to know for sure if a nerve injury is in fact<unk>  is to allow for the normal progression of nerve regeneration to take place (nerves regenerate at a rate of approximately 2–4 mm/day proximal to the lesion), and if, after that time, there is still profound muscle paralysis and degeneration in these areas, then it is likely to have been a<unk>  injury.<unk>  is diagnosed through clinical evaluation of symptoms, physical evaluation, and other diagnostic studies. Patients often undergo a series of muscle strength tests, sensory exam which includes feeling the sensation of light touch, pinprick, vibration, and others. Other tests involved with diagnosis of nerve injury are electromyography (EMG) and nerve conduction studies (NCS). These help to distinguish upper from lower motor neuron disorder as well as diagnose primary muscle disease. Classification Peripheral nerve injuries can be classified in two different ways.<unk>  is classified under the Seddon system which is defined by three grades of nerve injury. The mildest grade is referred to as neurapraxia and is characterized by a reduction or complete blockage of conduction across a segment of nerve while axonal continuity is maintained and nerve conduction is preserved. These injuries are almost always reversed and a recovery takes place within days or weeks. The second classification of the Seddon system is referred to as axonotmesis which is a more severe case of peripheral nerve injury. Axonotmesis is classified by an interruption of the axons, but a preservation of the surrounding connective tissues around the axon. These injuries can heal themselves at about 1mm/day, therefore resulting in recovery to be possible but at a slower rate than neurapraxia. The last and most severe case of peripheral nerve injury is known as<unk> , which in most cases cannot be completely recovered from even with surgical repair. The second classification of nerve injury is known as the Sunderland classification which is more complex and specific. This classification uses five different degrees of nerve injury, the first one being the least severe and the equivalent to neurapraxia and the most severe being the fifth degree and having the same classification as<unk> . The second through fourth degrees are dependent on the variance of axon discontinuity and are classified under Seddon’s classification of axonotmesis.
Neurotmesis
Axonotmesis
Hutchinson's mask
Laryngeal mask airway
Electrolarynx
Cragie tube
Surgical mask
Schimmelbusch mask