In 6 patients with endocrine ophthalmopathy, indications, surgical technique and results of the endoscopic controlled endonasal orbital decompression are described in comparison to the common surgical procedures. When medical and radiation therapy fail, indications for decompression are a) loss of visual acuity or visual field defects, b) increasing strabismus, c) severe keratopathy due to eyelid retraction. The endoscopic-controlled endonasal surgical decompression technique is proceeded in three steps. First, an endonasal ethmoidectomy with resection of the middle turbinate is performed and the medial wall of the maxillary sinus is widely opened. Second, the medial and inferior wall of the orbital walls are removed, preserving the infraorbital nerve. In the last step, the periorbital area is incised and the orbital fat herniates. The advantages of this procedure consist in the absence of exterior scars and the known morbidity of a Caldwell-Luc antrotomy. The results were documented by computed tomographic scans (CT), magnetic resonance imaging (MRI), Hertel measurements, evaluation of ocular motility and ophthalmoscopy. An average of 3-4 mm improvement in Hertel-measurements could be reached. All patients had a postoperative improvement of visual acuity. 2 patients developed more significant diplopia postoperatively, whereas in all other patients ocular motility either improved or rested unaffected. Therefore, the endoscopic controlled endonasal procedure allows to obtain comparable results to the common extranasal and transantral procedures without the disadvantages of the latter.
Zoom endoscopic electromyography of the larynx, as introduced in 1979, has contributed greatly to the diagnosis of lower cranial nerve palsies, but in the early stage of a vagus nerve disorder one cannot investigate the nerve conduction from the brain stem to the laryngeal muscles with electrical stimulation. As with the early diagnosis of facial nerve palsies, up to now the intracranial part of the motoric brain nerves could not be stimulated directly. With a new magnetic coil device (Novametrix, Magstim 200) this intracranial stimulation is easily possible in the awake patient with painless magnetic stimuli that induce a muscle action potential into the laryngeal muscles. Hence, an immediate diagnosis is possible. Two coils with mean diameters of 8.5 or 3 cm were used. The stimulator delivered current pulses of peak amplitude up to 5,000 A with rise times of 140 microseconds and 65 microseconds, respectively, that generated peak fields of up to 2 T. In a healthy population, cisternal stimulation of the vagus nerve leads to a muscular response in the vocal muscle after 4 to 6.6 milliseconds (mean 5 milliseconds). Cortical stimulation leads to such a response after 9.5 to 12 milliseconds. Potentials in healthy individuals have been shown to be very uniform. Stimulation in recurrent nerve palsies may show prolongation of these latencies up to 30 milliseconds. The method is limited by the fact that complete neural blocks cannot be overcome by proximal stimulation. We have applied magnetic stimulation to 190 patients with different disorders of the vagus nerve.(ABSTRACT TRUNCATED AT 250 WORDS)
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