Indications

The indications for this are limited. All too often, damage to the optic nerve is recognized days after the trauma that caused it. The type of head injury that leads to optic nerve damage is usually associated with significant brain damage, whose management takes precedence. The clinical picture is normally clouded by the overall neurological status of the patient. Assessing the optic afferent pathway in these circumstances is not easy, as the patient often requires ventilation and is paralyzed. Under these circumstances, it may be inappropriate for the patient to undergo a a c

Removal Turbinate Bones

Fig. 14.48 a Axial CT scan showing a posttraumatic fragment of bone pressing on the optic nerve (arrow). b Peroperative endoscopic view showing removal of the bony fragment (*) responsible 4 hours after accident. c Partial loss of vision returned following removal of the bony fragment and decompression of the orbit.

Fig. 14.48 a Axial CT scan showing a posttraumatic fragment of bone pressing on the optic nerve (arrow). b Peroperative endoscopic view showing removal of the bony fragment (*) responsible 4 hours after accident. c Partial loss of vision returned following removal of the bony fragment and decompression of the orbit.

b c surgery, particularly if they have a Glasgow coma scale score of less than 8 (Jones et al., 1997b). If there is a skull base fracture included in the sphenoid and there is evidence of an afferent defect, then further investigations, including visual evoked potentials (Jones, 1997) or usually a swinging light test (Mason et al., 1998 a), should be done. If these are abnormal, then the question remains when it is appropriate to decompress the optic nerve. Several studies suggest that with retro-orbital hemorrhage, decompression of the orbit needs to be done in less than one hour (Mason et al., 1998 a). However, where there is no hemorrhage, it is less clear under what circumstances it is beneficial to decompress the nerve pathway.

High-dose steroids are the primary treatment of choice in traumatic optic neuropathy (Sofferman, 1995). However, if the optic nerve function is deteriorating in spite of these it would seem reasonable to intervene (Jiang et al., 2001). If there is an anatomical constriction on CT scans affecting the course of the optic nerve and the patient is fit for anesthesia, then it seems reasonable to remove the bone pressing on the nerve (Fig. 14.48a-c). While the results of optic nerve decompression have been encouraging, the assessment of these patients, the state of the afferent pathway, and knowledge of the ability of the optic nerve to improve without any intervention are too limited to allow clear guidelines at present.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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