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Experimental Research of Operative Time Selection after Traumatic Optic Nerve Injuries

Author: WuKun
Tutor: ShiJiXin
School: Southern Medical University,
Course: Surgery
Keywords: Optic nerve / injury Pathology Evoked potentials Sight
CLC: R779.6
Type: Master's thesis
Year: 2008
Downloads: 30
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Abstract

Background: traumatic optic nerve injury (Traumatic Optic Neuropathy, TON) vision caused by the trauma under part or all of the temporary or permanent loss leading to blindness, is one of the common causes of disability after injury. More common in the craniofacial complex injuries in recent years, with the incidence of traffic accidents has increased every year, there are a growing trend in the incidence of TON. For the diagnosis and treatment of traumatic optic neuropathy, is still a lack of mature and unified understanding. Carried out in the clinical optic nerve decompression is one of the commonly used method, but at the same time due to the type of trauma is often associated with serious brain and facial trauma occurred early after injury concern to save lives, to be discovered TON often missed the best timing of treatment, often resulting in permanent visual impairment, traumatic optic nerve damage surgical timing is always the concern of the medical profession. Objective: This study by the forward-looking animal studies, the establishment of the rabbit optic nerve crush injury model to understand the possible mechanism of injury, the systematic observation of optic nerve injury model in different periods after decompression tissue morphology and visual evoked potential change, understand the traumatic appropriate relationship between the timing of surgery and efficacy of optic nerve damage, to investigate the optimal timing of surgery, while exploring the the TON pathogenesis of clinical surgical treatment of traumatic optic neuropathy provide a theoretical basis for the surgical treatment of traumatic optic neuropathy surgery time limit provide a reference. Materials and Methods: rabbits traumatic optic neuropathy and different time decompression model, were randomly divided into normal control, injury two days decompression (d), 7 days (d) decompression, decompression group 14 days (d) damage decompression group. After the pattern reversal visual evoked potential (Pattern Reversal Visual Evoked Potential, P-VEP) testing control group of visual function, injury 2d decompression, 7d decompression 14d decompression injury before and after 1 hour (h), the different periods of decompression (1H, 2 weeks) and the injury is not corresponding set of visual function of the time change reduced pressure. Two weeks after the histological changes observed in each group of the optic nerve in the light microscope. Results: 1. Pathology observed: 1.1 normal control group: light microscopy, normal optic nerve glial cells of the longitudinal section of substantially uniform cylindrical arrangement, the nerve fibers arranged in neat rows, arranged in parallel to the longitudinal interstitial uniform matrix red dye, no obvious inflammatory cell infiltration, interstitial rich thin-walled blood vessels. 2d the decompression group of: 1.2 injury the longitudinal section glial cell arrangement is essentially uniform, damage seen at vacuolar degeneration, optic slightly swollen, the perivascular slightly oozing; 1.3 damage 7d after decompression: optic nerve damage visible section glue interstitial cells arranged in disorder. Multiple vacuoles of varying sizes in most of the region, some areas appear demyelinating like change, part of the axon bare perivascular exudation local visible gliosis; the 1.4 injuries after 14d decompression Group: optic nerve complete loss of the longitudinal section of the glial cells of the damaged area cylindrical arrangement, the full vision glial cells were hyperplasia, optic nerve demyelination like change significantly, partially visible small necrotic occasionally macrophage infiltration, perivascular exudation alleviate part of the vascular seen in inflammatory infiltration. 1.5 injuries after decompression: optic nerve damage area visible large areas of necrosis, optic nerve demyelination kind of obvious and serious vascular leakage, gliosis. Visual evoked potentials: the 2.1 pet healthy rabbits P-VEP examination leads to typical NPN curve, after optic nerve crush low 1h NPN waveform wide flat prolonged P-wave latency and amplitude decreased with their own injury and normal group the difference was statistically significant (P = 0.000). 2.2 decompression before and after the group self-control: (1) injury 2d decompression group before and after the decompression latency and amplitude of the difference was statistically significant (P = 0.000); the 7d the decompression group of decompression (2) damage before and after the incubation period with volatility differences have significant significance (P = 0.000); (3) damage 14d decompression group of decompression before and after the volatility of the difference was significant significance (P = 0.000), while the latency difference there is significant significance (P = 0.000) . 2.3 decompression after two weeks of each group visual evoked potential comparison between: (1) injury 2d decompression, decompression group 7 days after injury, after injury 14d decompression group pairwise comparisons: between the three groups latent period were significantly significance (P = 0.000), decompression injury 2d decompression injury 7d after injury 14d decompression volatility comparison, the difference was statistically significant (P = 0.000), and 7 days after injury decompression group, injury 14d the decompression group of between volatility differences were significant (P = 0.000); (2) in each group and the injury is not decompression group: 2d decompression injury, decompression group 7 days after injury and damage unabated latency and amplitude differences between pressure groups have significant significance (P = 0.000), injury 14d decompression injury decompression was no significant difference between the groups (P> 0.05); conclusions: 1. nerve $ secondary injury decreased visual function, protect neurons from secondary damage is depending on the function of the protection of the important aspects of primary injury; 2. optic nerve decompression will help reduce the indirect optic damage , early decompression after optic nerve injury distant period of decompression to better protect visual function can be reversed, as the function of the damage to some extent, the earlier (1 week) can prevent axon secondary injury decompression to avoid visual function decline further.

Experimental Research of Operative Time Selection after Traumatic Optic Nerve Injuries

Abstract

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