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Nelson M. Oyesiku

✓ A contemporary review of the use of stereotactic radiosurgery in the treatment of Cushing disease (CD) is presented with information drawn from a literature review and from the author's experience. Stereotactic radiosurgery is an effective and safe therapeutic alternative for treating CD in carefully selected cases. Improvements in imaging, dose planning, and general understanding of radiobiology are likely to yield better results in the future.

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Nelson M. Oyesiku and Robert K. Jones

✓ A case is reported in which a Heifetz aneurysm clip, applied for the treatment of an aneurysm of the posterior inferior cerebellar artery, slipped and migrated into the cauda equina resulting in lumbar radiculopathy. Related reports are discussed briefly.

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Nelson M. Oyesiku and Kalmon D. Post

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Nelson M. Oyesiku, Daniel L. Barrow, James R. Eckman, Suzie C. Tindall, and Austin R. T. Colohan

✓ Intracranial aneurysms are an unusual complication of sickle-cell anemia; only 15 patients have been described in the world literature. An additional 15 patients with sickle-cell anemia and subarachnoid hemorrhage (SAH) from ruptured intracranial aneurysms are presented. There was a high incidence of multiple aneurysms (60%); some of which were in unusual locations. The clinical and pathological features of this series of patients have provided a paradigm for acquired aneurysm formation that may be applicable to other intracranial aneurysms. Thirteen patients underwent craniotomy and clip ligation; the perioperative management of these patients is discussed. Of these 13, eight had a good recovery, three were left with moderate disability, one patient died of surgical complications, and one died of complications related to sickle-cell anemia. Two of the 15 patients died of SAH. The authors propose that endothelial injury from the abnormal adherence of sickle erythrocytes to the endothelium is the initiating event in arterial wall injury. Subsequently, there is fragmentation of the internal elastic lamina and degeneration of the smooth-muscle layer. Hemodynamic stress at these loci of arterial wall damage results in aneurysm formation. This hypothesis also explains other cerebrovascular manifestations of sickle-cell anemia, namely vaso-occlusive disease and hemorrhage without aneurysm formation. Pathological material from this series and data from the literature are presented to support this hypothesis.

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George T. Tindall, Nelson M. Oyesiku, Nelson B. Watts, Richard V. Clark, James H. Christy, and David A. Adams

✓ The results of transsphenoidal adenomectomy for growth hormone (GH)-secreting pituitary adenomas in acromegaly performed over a 17-year period were analyzed retrospectively to determine which preoperative factors significantly influenced the long-term surgical outcome. These variables were then used to develop a logistic regression model to determine the probability of surgical failure.

The series consisted of 103 patients. Long-term follow-up study (mean duration 102 ± 64 months) was performed to derive outcome analysis and determinants of failure. Surgical control was defined as a long-term postoperative serum basal GH level of less than 5 µg/liter, a long-term postoperative serum somatomedin C (SM-C) level of less than 2.2 U/ml, and a favorable clinical response. Eighteen (17.5%) patients did not meet these criteria. The overall control rate by the GH criteria was 81.3% and by the SM-C criteria 76.2%.

By multivariate logistic regression analysis, tumor stage was the strongest predictor of outcome (p < 0.05). The preoperative GH level, tumor grade, and preoperative SM-C level were significant univariate predictors (p < 0.05). There were statistically significant differences in mean preoperative GH and SM-C levels (p < 0.05, t-test) and tumor stage (p < 0.05, chi-squared test) between patients whose acromegaly was controlled by surgery and those whose acromegaly was not. Furthermore, estimates were derived of the probability of surgical failure based on preoperative GH level, preoperative SM-C level, and tumor grade and stage. The authors believe these findings will enhance clinical decision-making for neurosurgeons considering transsphenoidal microsurgery in patients with acromegaly.

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Nelson M. Oyesiku