Clinical neurophysiology and imaging of nerve injuries: preoperative diagnostic work-up and postoperative monitoring

Abstract

Peripheral nerve injuries are a heterogeneous group of lesions that may occurs secondary to\ud various causes. Several different classifications have been used to describe the pathophysiological\ud mechanisms leading to the clinical deficit, from simple and reversible compression‑induced\ud demyelination, to complete transection of nerve axons. Neurophysiological data localize, quantify,\ud and qualify (demyelination vs. axonal loss) the clinical and subclinical deficits. High‑resolution\ud ultrasound can demonstrate the morphological extent of nerve damage, fascicular echotexture\ud (epineurium vs. perineurium, focal alteration of the cross‑section of the nerve, any neuromas, etc.),\ud and the surrounding tissues. High field magnetic resonance imaging provides high contrast\ud neurography by fat suppression sequences and shows structural connectivity through the use\ud of diffusion‑weighted sequences. The aim of this review is to provide clinical guidelines for the\ud diagnosis of nerve injuries, and the rationale for instrumental evaluation in the preoperative and\ud postoperative periods. While history and clinical approach guide neurophysiological examination,\ud nerve conduction and electromyography studies provide functional information on conduction\ud slowing and denervation to assist in monitoring the onset of re‑innervation. High‑resolution nerve\ud imaging complements neurophysiological data and allows direct visualization of the nerve injury\ud while providing insight into its cause and facilitating surgical treatment planning. Indications and\ud limits of each instrumental examination are discussed

Human Motor Endplate Survival after Chronic Peripheral Nerve Injury

“…14 Increasing fibrillation potential grades correlate with increased severity of nerve damage. 15 Of the muscle biopsy cohort, 1 patient had 4+ fibrillation potentials, 7 had 3+ fibrillation potentials, and 1 had 1+ fibrillation potentials. Distribution of fibrillation potentials for the other cohort of patients was: 2 had 3+ potentials, 7 had 2+ potentials and 1 patient had 1+ potentials.…”

Bipolar Radiofrequency-Assisted Liposuction for Cervical Contouring in Eastern Asians

“…This finding is consistent with previous reports that nerve recovery occurs after remyelination and that sensorimotor functions can usually be fully restored within days to weeks without sequelae. 20 , 21 Neuropraxia was caused by temporary interruption in the conduction of nerve impulses and motor function, which was a consequence of trauma to the nerve fibers without nerve rupture. Given that the marginal nerve was dominant for lower lip depressor function, temporary unilateral neuropraxia of the marginal branch of the mandibular nerve resulted in paralysis of the ipsilateral depressor anguli oris muscle.…”

Imaging diagnosis in peripheral nerve injury

“…Magnetic resonance imaging (MRI) can reveal pathological changes in peripheral nerves (35,36,(40)(41)(42)(43)(44)(45). Affected nerves and associated structures show changes in both morphology and signal intensity when observed with the assistance of magnetic resonance imaging (45).…”

“…Magnetic resonance imaging (MRI) is a non-invasive imaging based diagnostic tool that can be employed to detect peripheral nerve injury ( 35 , 36 ). High magnetic field MRI imaging can be utilized to execute high contrast neurography with the help of fat suppression sequences and this kind of imaging modality enables us to observe structural connectivity through the use of diffusion tensor imaging and tractography ( 35 ).…”

“…Magnetic resonance imaging (MRI) is a non-invasive imaging based diagnostic tool that can be employed to detect peripheral nerve injury ( 35 , 36 ). High magnetic field MRI imaging can be utilized to execute high contrast neurography with the help of fat suppression sequences and this kind of imaging modality enables us to observe structural connectivity through the use of diffusion tensor imaging and tractography ( 35 ). Peripheral nerve MRI can reveal pathological changes such as nerve compression, inflammation, or tumors in peripheral nerves and other associated components of the peripheral nervous system ( Figure 3 ) ( 36 ).…”