1/2. Delayed visual deterioration after pituitary surgery--a review introducing the concept of vascular compression of the optic pathways.BACKGROUND: Delayed visual deterioration after pituitary surgery has been attributed to secondary empty sella syndrome and downward herniation of the optic nerves and chiasm, but the pathophysiological basis of this condition is still a matter of debate. review: According to the literature, prior radiation therapy, previous visual impairment and transcranial surgery constitute risk factors for delayed visual deterioration. radiation-induced vascular changes and/or strangulation of the optic nerves or chiasm are thought to compromise local blood flow. Downward herniation of the optic pathways was present in the majority of cases, but did not correlate with visual symptoms and signs, while dense scarring of the chiasm was a reproducable finding in all surgically explored cases. Indentations in the upper margin of the optic nerves or chiasm caused by the A1 segments of the anterior cerebral arteries have been reported repeatedly. As perichiasmal scarring constitutes the most consistent finding, the intimate relationship between artery and nerve with consecutive pulsatile pressure may constitute a causative factor in delayed visual dysfunction after pituitary surgery. The authors therefore introduce the concept of vascular compression, which is illustrated with a personal case of a successful decompression procedure with teflon interposition between the A1 segment and the non-herniated optic nerve to treat visual loss eight months following removal of a hemorrhagic pituitary adenoma. CONCLUSIONS: Clinicians should be aware that surgical exploration via a transcranial approach is indicated in cases of progressive visual loss late after pituitary surgery, no matter whether downward displacement of the optic pathways is present on imaging studies or not. Special attention should be paid intra-operatively to the dissection of the intimate relationship between the anterior cerebral arteries and the optic nerves and chiasm.- - - - - - - - - - ranking = 1keywords = pressure (Clic here for more details about this article) |
2/2. Bilateral visual loss complicating liposuction in a patient with idiopathic intracranial hypertension.A 34-year-old obese woman developed blurred vision in both eyes soon after large-volume liposuction of the dorsum and gluteus region bilaterally associated with abdominal dermolipectomy. An ophthalmic examination revealed severe bilateral visual loss and pallid optic disc edema. The patient gave a history of transient obscurations of vision in the past. neuroimaging studies were non-revealing, but a lumbar puncture disclosed a markedly elevated intracranial pressure. The patient was diagnosed as having had bilateral ischemic optic neuropathy superimposed on pre-existing idiopathic intracranial hypertension (IIH). acetazolamide treatment was used. Some visual improvement occurred, and optic disc edema evolved into severe optic disc pallor. This case shows that visual loss from optic disc infarction may be a devastating complication of high-volume liposuction in patients with underlying IIH. Because liposuction is frequently performed on obese patients, physicians should screen for signs and symptoms of IIH before undertaking this procedure.- - - - - - - - - - ranking = 1keywords = pressure (Clic here for more details about this article) |