[Controversies and current status of therapy of optic nerve damage in craniofacial traumatology and surgery]

Abstract

In craniomaxillofacial traumatology, surgical oncology and craniomaxillofacial reconstruction, a surgeon's aim may interfere with the prechiasmatic visual pathway. Precise concepts and therapeutic strategies are mandatory to detect and deal with anterior visual pathway disorders. In order to develop these strategies, knowledge of the pathomechanisms of potential optic nerve trauma, primary radiological investigations, and further diagnostic measures are important. Due to the difficulties in neuroophthalmological testing of visual pathway functioning in severely injured patients or even during craniomaxillofacial reconstructions, we established flash-evoked visual potentials (VEP) and the electroretinogram (ERG) as reliable electrophysiological methods to gather specific information as to whether the visual pathway function is intact, even if pathological, but still present or absent. Case reports show that subjectively or objectively confirmed unilateral amaurosis does not necessarily mean irreversible vision loss. The electrophysiological evaluation together with multiplanar computer tomography (CT) are important for the immediate identification of optic nerve trauma. The results of this evaluation will provide the diagnostic information on whether surgical intervention and/or conservative therapy is required to prevent secondary optic nerve damage. The conservative therapy of choice for the treatment of traumatic optic nerve lesions is the methylprednisolone-megadosis regimen (30 mg Urbason/kg bodyweight i.v. and 5.4 mg/kg bodyweight/h i.v. for the following 47 h). Surgical therapy involves decompression of the orbital compartment in case of retrobulbar hematoma or decompression of the intracanalicular part of the optic nerve in the traumatized optic canal or posterior orbit as confirmed by CT. Prospective analysis of our trauma patients and the international literature on traumatic optic nerve lesions show that the time factor in when to start therapy has been greatly underestimated. To fulfill modern treatment concepts in craniomaxillofacial surgery, sound diagnostic and therapeutic knowledge on the maintenance of visual pathway function is required.