Surgical considerations regarding giant dilations of the perivascular spaces

Journal ArticleObject. Dilations of brain perivascular spaces (PVSs), also known as Virchow-Robin spaces, are routinely identified on magnetic resonance imaging studies of the brain and recognized as benign normal variants. Giant dilations occur only rarely and can be easily misdiagnosed as central nervous system tumors. The relevant surgical literature was reviewed to help establish indications for surgical intervention in these typically benign lesions. Methods. Giant dilations of the PVSs in 12 patients who had undergone surgery for several different indications were identified. Both clinical and radiographic presentations of these patients were reviewed along with the surgical procedures. Conclusions. Dilations of the PVSs can become giant lesions that may necessitate surgical intervention to relieve mass effect or hydrocephalus. The relationship of these lesions to neurological symptoms such as tremor and seizures remains unclear

Astrocytoma cell line

Journal ArticleTO THE EDITOR: It has long been established clinically that patients with neurofibromatosis Type 1 (NF1) have an increased susceptibility to develop many central and peripheral tumors. The nature of the genetic alterations underlying NF1 have recently begun to be characterized. It has been demonstrated that the NF1 gene plays a critical role as a tumor suppressor and that patients with NF1 harbor mutations in the NF1 gene, which codes for neurofibromin, a functional negative regulator of signal transduction through Ras. Neurofibromatosis Type 1 is an autosomal-dominant cancer predisposition syndrome in which 15 to 20% of affected individuals develop astrocytomas that are most commonly pilocytic. The power of cell culture as a foundation of current molecular and cell biology is often not apparent to clinicians in the direct daily management of their patients. In the article by Kurimoto, et al. (Kurimoto M, Hirashima Y, Ogiichi T, et al: Establishment and characterization of a novel malignant astrocytoma cell line derived from a tumor removed in a patient with neurofibromatosis Type 1. J Neurosurg 94:301-308, February, 2001), the authors have established in tissue culture an immortalized cell line (TM-31) from a high-grade glioma in a patient with NF1. Although malignant glioma lines are established routinely in most laboratories in which intracranial tumors are studied, to date there has been no available established glioma line from a patient with NF1. This cell line offers a unique opportunity to study the genetic alterations, growth, and invasive characteristics in vitro

Diagnosis and management of Cushing disease

Journal ArticleThe management of a case involving Cushing disease, defined as excess secretion of adrenocorticotropic hormone (ACTH) from a pituitary adenoma, remains one of the most vexing problems facing the pituitary surgeon. The systemic consequences of this endocrinopathy are profound morbidity and premature death in the unfortunate patients in whom remission fails to occur. For this reason, the challenge to endocrinologists and neurosurgeons charged with treating these patients is normalization of pathological ACTH and, thus, serum cortisol levels. Unfortunately, transsphenoidal surgery fails to produce remission of symptoms in a significant percentage of patients, and repeated surgery or the institution of adjuvant therapy must be considered in such cases. In this issue of Neurosurgical Focus, a series of papers has been selected to provide a comprehensive overview of the diagnosis and management of this complicated disease. Papers involving the contemporary diagnostic workup and pitfalls, as well as success rates and outcomes following transsphenoidal surgery, are presented. Author's present various treatment options for patients in whom initial surgery has failed to resolve symptoms. A fascinating review paper on the phenomenon of brain atrophy seen in Cushing disease and its possible pathogenesis is included. Finally, two papers?one a historical overview and the other a contemporary review of the management of Nelson syndrome, a dreaded complication of an aggressive ACTH-secreting tumor of the pituitary developing after bilateral adrenalectomy?are presented. I would like to acknowledge the efforts of Margie Shreve and Dr. Martin Weiss. Without their expert and timely help, compiling this issue would not have been possible

De novo fenestration of the optic nerve

Journal ArticleFenestration of the optic nerve or chiasm due to the presence of an aneurysmal dilation of the internal carotid artery (ICA) has been described previously. In three of five cases reviewed recently, the optic nerve was penetrated by an ICA?ophthalmic artery aneurysm.3 Penetration of the optic nerve was due to a ruptured anterior communicating artery aneurysm or an aneurysm of the anterior wall of the ICA in the other cases published to date.2,4 Splitting of the optic nerve without the presence of a penetrating aneurysm has not been identified previously. This 50-year-old woman was found to have multiple unruptured aneurysms during an evaluation for refractory tinnitus and headaches. The patient harbored a complex 2-cm aneurysm of the left middle cerebral artery as well as an 8-mm aneurysm at the origin of the right posterior communicating artery. Each of the aneurysms was successfully obliterated with clip ligation during separate operations. During surgery for the right-sided aneurysm, a unique structure of the medial left optic nerve and chiasm was identified (Fig. 1). The smaller portion of the optic nerve was dissected free of the investing arachnoid and was noted to course with the main portion of the nerve toward the optic canal. A cause of the split, such as a penetrating embryonic artery or osseous trabeculae, could not be identified. Several mechanisms have been proposed to explain how an enlarging aneurysm might split the optic nerve. One mechanism would involve a congenital fenestration through which an aneurysm passes. 4 Indeed, duplications of the optic canals have been identified in cadaveric specimens, indicating congenital optic nerve duplication is possible.1 Nevertheless, because this case illustration is the first report we are aware of to demonstrate a de novo optic nerve fenestration, it would appear that congenital fenestrations are extremely rare

Personal perspective: AANS Bulletin's momentum continues: new editor considers peer review, practice survey impact

Journal ArticleWith this issue, I assume the reins as editor of the AANS Bulletin. I am indebted to James Bean, MD, for his extraordinary efforts in this capacity, as witnessed by review of the recent issues published under his leadership. An important initiative put forth by Dr. Bean and the Bulletin Advisory Board is the establishment of the peer-review portion of the Bulletin. The peer-review mechanism is intended to encourage submissions of hypothesis-driven research relating to issues that affect the practice of neurosurgery

Revision of vagal nerve stimulator electrodes: technical approach

ManuscriptPurpose To demonstrate the feasibility of complete removal of the vagal nerve stimulator electrode using microsurgical technique. Methods Operative databases at the University of Utah (1995 through 2002), Westchester Medical Center (1995 through 2001), and University of Arizona Health Sciences Center (1995 through 1999) were retrospectively reviewed. Patients who had undergone removal or revision of a previously placed vagal nerve stimulator electrode were identified. Patients who had a vagal nerve stimulator device removed but had the lead trimmed and incompletely removed were excluded. Results Seven patients underwent complete removal of the lead. Microsurgical dissection allowed removal of the helical electrode from the vagus nerve without apparent physiological consequences. Four patients had a new electrode placed just proximal to the original lead site. The operative procedure required an additional 30 minutes to complete compared with initial device placement. The four patients who underwent replacement of the electrode demonstrated normal device function and lead resistance at the time of postoperative follow-up. Each experienced a return to prior stimulation response and seizure control. Conclusions This series suggests that the electrode can be removed from the vagus nerve and repositioned without significant consequence in most cases

Giant pituitary tumor combined approach

Journal ArticleNishioka et al. have provided a review of 29 patients with large pituitary adenomas who underwent surgery through a simultaneous transsphenoidal and transcranial approach at their institution during a 7-year period. Large adenomas with hourglass constriction, complex lobulations, and asymmetric extension were the primary indications for the simultaneous combined approach. The transcranial approaches used were the pterional approach in 17 patients, interhemispheric approach in 8, and transventricular (transcortical) approach in 4 patients. The results of the series of patients were carefully tabulated. The investigators are to be commended on their very good results with this difficult group of patients

William Osler at McGill University: the baby professor and his early contributions to neurosurgery

Journal ArticleBetween 1870 and 1884, as both a medical student and a member of the faculty, Sir William Osler performed approximately 1000 postmortem examinations at McGill University in Montreal. He conducted 786 of these examinations during his 7 years (1877-1884) of service as a pathologist at the M were carefully recorded and catalogued either by him or by those who compiled the Pathological Report of the Hospital. Included in this material are many early descriptions of neurosurgical disease. Osler used this information for subsequent teaching in both Philadelphia and Baltimore. Osler's early and lifelong special interest in diseases of the nervous system not only led him to make seminal observations but also served to initiate his influence and relationships with the emerging leaders in neurology and neurosurgery

Tunneled lumbar drain

Journal ArticleThe authors report a simple and rapid procedure for tunneling a lumbar drain subcutaneously to facilitate chronic cerebrospinal fluid (CSF) drainage. A standard lumbar puncture (LP) is performed with a large-bore Tuohy needle (14- to 16-gauge), the drainage catheter is advanced into the subarachnoid space, and the needle is removed. The free Tuohy needle is then passed from a lateral position and brought out through the initial LP site. The free catheter is fed through the needle, and the needle is removed. The drain is attached to an external drainage bag in the usual manner. The authors have found this method particularly useful in some skull base and spinal surgical applications in which longer term continuous CSF drainage is desired

Technique for methyl methacrylate cranioplasty to optimize cosmetic outcome

pre-printBackground: Cranioplasty aims to reconstruct skull defects from fractures, decompressive craniectomies, tumors, and congenital anomalies in a cosmetically acceptable manner. We present a technique in methyl methacrylate cranioplasty that gives excellent cosmetic results by maintaining patient's calvarial curvature. Method: Cranioplasty material is placed into a plastic bag and packed inside the defect. Wire mesh cut larger than the defect is held in position to take the exact skull curvature. Once solid, the implant is fixed in position using titanium plates and mini-screws. Conclusion: This is a simple, inexpensive method of achieving the most cosmetically desired cranioplasty results