Cerebral revascularization, an indispensable component of neurovascular surgery, has been performed in the treatment of cranial base tumors, complex cerebral aneurysms, and occlusive cerebrovascular disease. The goal of a revascularization procedure is to augment blood flow distally. It can therefore be used as an adjunctive measure in the treatment of complex neurosurgical disease processes that require parent artery sacrifice for definitive treatment. In the treatment of giant anterior circulation aneurysms, for instance, a cerebral revascularization procedure may be considered in patients in whom the collateral circulation is marginal and in whom lesions may be treated either using a Hunterian-based strategy or clip-assisted reconstruction requiring a prolonged period of temporary occlusion. To date, there is no entirely effective method known to produce long-term tolerance to carotid artery (CA) sacrifice and, largely for that reason, some neurovascular surgeons advocate universal revascularization. The authors of this report, however, prefer to perform revascularization only in the limited subset of patients in whom preoperative assessment has revealed risk factors for cerebral ischemia due to hypoperfusion. In this paper, the authors introduce their protocol for assessing cerebrovascular reserve capacity, indications for cerebral revascularization in the treatment of complex anterior circulation aneurysms, and discuss their rationale for choosing to practice selective, rather than universal, revascularization.
Brian A. O'Shaughnessy, Sean A. Salehi, Stefan A. Mindea and H. Hunt Batjer
Stefan A. Mindea, Sean A. Salehi, Aruna Ganju, Michael K. Rosner, Brian A. O'Shaughnessy, Allan Jorge and Stephen L. Ondra
Lumbosacropelvic junction instability may result from a variety of disease processes including primary and meta-static sacral tumors and degenerative disease. Regardless of the origin of the disease, restoring or maintaining spinal stability at this junction is essential for normal translation of axial forces from the lumbar spine and sacrum to the pelvis. Spinal stability is also critical for maintaining structural integrity, preventing neurological function deterioration, and alleviating resultant mechanical or axial pain. In this report, the authors describe one option for safe and effective spinal pelvic stabilization by using a transiliac rod and iliac bolt construct, which results in early postoperative ambulation, preserved neurological function, and reduced axial pain in selected patients.
Benson P. Yang, Stefan A. Mindea and Arthur J. DiPatri Jr.
Stefan A. Mindea, Benson P. Yang, Robert Shenkar, Bernard Bendok, H. Hunt Batjer and Issam A. Awad
✓ Familial disease is responsible for one third to one half of cerebral cavernous malformation (CCM) cases presenting to clinical attention. Much has been learned in the past decade about the genetics of these cases, which are all inherited in an autosomal dominant pattern, at three known chromosome loci. Unique features of inherited CCMs in Hispanic-Americans of Mexican descent have been described. The respective genes for each locus have been identified and preliminary observations on disease pathways and mechanisms are coming to light, including possible explanations for selectivity of neural milieu and relationships to endothelial layer abnormalities. Mechanisms of lesion genesis in cases of genetic predisposition are being investigated, with evidence to support a two-hit model emerging from somatic mutation screening of the lesions themselves and from lesion formation in transgenic murine models of the disease. Other information on potential inflammatory factors has emerged from differential gene expression studies. Unique phenotypic features of solitary versus familial cases have emerged: different associations with venous developmental anomaly and the exceptionally high penetrance rates that are found in inherited cases when high-sensitivity screening is performed with gradient echo magnetic resonance imaging. This information has changed the landscape of screening and counseling for patients and their families, and promises to lead to the development of new tools for predicting, explaining, and modifying disease behavior.
Stefan A. Mindea, Benson P. Yang, Bernard R. Bendok, Jeffrey W. Miller and H. Hunt Batjer
✓Cerebral vasospasm is a significant cause of morbidity and mortality in patients who have sustained a subarachnoid hemorrhage from aneurysm rupture. Symptomatic cerebral vasospasm is also a strong predictor of poor clinical outcome and has thus drawn a great deal of interest from cerebrovascular surgeons. Although medical management is the cornerstone of treatment for this condition, endovascular intervention may be warranted for those in whom this treatment fails and in whom symptomatic vasospasm subsequently develops. The rapid advancements in endovascular techniques and pharmacological agents used to combat this pathological state continue to offer promise in broadening the available treatment armamentarium. In this article the authors discuss the rationale and basis for using the various endovascular options for the treatment of cerebral vasospasm, and they also discuss the limitations, complications, and efficacy of these treatment strategies in regard to neurological condition and outcome.
Case report and review of the literature
Stefan A. Mindea, Benson P. Yang and H. Hunt Batjer
✓The authors report on a patient harboring an unruptured cortical arteriovenous malformation (AVM), who had presented with obstructive hydrocephalus due to compression of the cerebral aqueduct by a large venous varix. Although patients with ruptured AVMs are known to either present with or later suffer from obstructive hydrocephalus, those with unruptured AVMs who present in this manner are quite rare. Moreover, hydrocephalus caused by a venous varix draining an AVM, to our knowledge, has never been previously reported in the literature. This report serves to illustrate two primary points, namely, that tortuous venous varices draining AVMs can result in obstructive hydrocephalus and that this unusual circumstance can be fostered in the setting of venous outflow obstruction.
Stefan A. Mindea, Keith J. Kaplan, Michael A. Howard and Shaun T. O'leary
✓Granular cell tumors (GCTs) are benign lesions that, paradoxically, despite originating from the Schwann cell, are most commonly seen in nonneuronal tissue including the skin, subcutaneous tissue, and tongue. Their presence in the brachial plexus is quite rare, but their involvement of peripheral nerves is exceptional. The authors report on a case of GCT involving the axillary nerve in a 54-year-old woman who underwent complete resection of the lesion. To the author's knowledge, this case marks the first report of a GCT involving the axillary nerve. Aspects pertaining to the radiographic and histopathological features as well as the surgical management of this lesion are discussed.
Varun R. Kshettry, Stefan A. Mindea and H. Hunt Batjer
✓Cranial injuries were among the earliest neurosurgical problems faced by ancient physicians and surgeons. In this review, the authors trace the development of neurosurgical theory and practice for the treatment of cranial injuries beginning from the earliest ancient evidence available to the collapse of the Greco–Roman civilizations. The earliest neurosurgical procedure was trephination, which modern scientists believe was used to treat skull fractures in some civilizations. The Egyptian papyri of Edwin Smith provide a thorough description of 27 head injuries with astute observations of clinical signs and symptoms, but little information on the treatment of these injuries. Hippocrates offered the first classification of skull fractures and discussion of which types required trephining, in addition to refining this technique. Hippocrates was also the first to understand the basis of increased intracranial pressure. After Hippocrates, the physicians of the Alexandrian school provided further insight into the clinical evaluation of patients with head trauma, including the rudiments of a Glasgow Coma Scale. Finally, Galen of Pergamon, a physician to fallen gladiators, substantially contributed to the understanding of the neuroanatomy and physiology. He also described his own classification system for skull fractures and further refined the surgical technique of trephination. From the study of these important ancient figures, it is clearly evident that the knowledge and experience gained from the management of cranial injuries has laid the foundation not only for how these injuries are managed today, but also for the development of the field of neurosurgery.
Bradley A. Gross, Stefan A. Mindea, Anthony J. Pick, James P. Chandler and H. Hunt Batjer
✓ In Cushing disease, a pituitary corticotroph neoplasm causes secondary adrenal hypercortisolism. This condition has known morbidity and mortality, underscoring the need for an efficient and accurate diagnostic approach. An 11 p.m. salivary cortisol level is a modern, simple initial screening tool for the diagnosis of Cushing syndrome. Confirmation with a 24-hour urinary free cortisol test and/or a low-dose dexamethasone suppression test may subsequently be performed. Patients with repeatedly equivocal results should be reevaluated after several months or undergo a corticotropin-releasing hormone (CRH) stimulation test following low-dose dexamethasone suppression to help rule out pseudo-Cushing states. The presence of low morning serum adrenocorticotropic hormone (ACTH) levels then distinguishes primary adrenal hypercortisolism from Cushing disease and the ectopic ACTH syndrome. Patients with moderate ACTH levels can undergo CRH stimulation testing to clarify the underlying disease because those with an ACTH-independent disorder have blunted subsequent ACTH levels. Once ACTH-dependent hypercortisolemia is detected, magnetic resonance (MR) imaging of the pituitary gland can be performed to detect a pituitary neoplasm. Normal or equivocal MR imaging results revealing small pituitary lesions should be followed up with inferior petrosal sinus sampling, a highly specific measure for the diagnosis of Cushing disease in experienced hands. If necessary, body imaging may be used in turn to detect sources of ectopic ACTH.
Bradley A. Gross, Stefan A. Mindea, Anthony J. Pick, James P. Chandler and H. Hunt Batjer
✓Although transsphenoidal excision of the adrenocorticotropic hormone (ACTH)–producing neoplasm is often the treatment of choice in patients with Cushing disease, medical management is itself a useful preoperative temporizing measure, an option for long-term management in nonsurgical candidates, and an option for patients in whom surgery and/or radiotherapy have failed. Three pathophysiologically based approaches exist in the research literature—neuro-modulation to limit ACTH levels, adrenal enzyme inhibition, and glucocorticoid receptor antagonism. Unfortunately, the neuromodulatory approach involving agents such as bromocriptine, cyproheptadine, octreotide, and valproate has yielded only suboptimal results. Glucocorticoid receptor antagonism remains in its infancy but may overall be limited by side effects and a resultant increase in ACTH and cortisol levels. Adrenal enzyme inhibitors, however, offer substantial future promise in the management of Cushing disease but are limited by the potential need to use them indefinitely and by dose-tolerance effects.
Although etomidate is a potential intravenous alternative for acute cortisol level control, ketoconazole has shown efficacy in the long-term treatment of patients with the disease. Metyrapone and/or aminoglutethimide can be added to ketoconazole if additional control is needed. If success is still not achieved, the potent adrenolytic agent often used for adrenocortical carcinomas, mitotane, is another alternative.