Surgical decompression in endocrine orbitopathy--a three-dimensional locating device ensures greater safety

Numerous techniques have been described for surgical decompression in endocrine orbitopathy. Irrespective of the approach chosen, the procedure might involve hazards to important vessels and nerves near the base of the skull. When the optic nerve is compressed and relief of pressure at the orbital apex is necessary, the internal carotid artery and the cavernous sinus are at risk as well as the optic nerve itself. Although the use of modern optical instruments such as operating microscopes and endoscopes is now standard practice for this form of surgery, adequate topographical orientation is not achieved in every case. For this reason a computer-assisted locating device developed in this department has been employed by us in 7 cases of endocrine orbitopathy where surgical decompression was required. By using computer-tomographic or MR-tomographic image data, the positions of structures at risk can be plotted to within 0.6 mm. Used in conjunction with an operating microscope and with endoscopic techniques, the system proved helpful in all cases.