✓ Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of the early mammalian embryo. Because of their plasticity and potentially unlimited capacity for self-renewal, ES cells have generated tremendous interest both as models for developmental biology and as possible tools for regenerative medicine. This excitement has been attenuated, however, by scientific, political, and ethical considerations. In this article the authors describe somatic cell nuclear transfer and transcription-induced pluripotency, 2 techniques that have been used in attempts to circumvent the need to derive ES cells by the harvest of embryonic tissue.
Sunit Das, Michael Bonaguidi, Kenji Muro, and John A. Kessler
Sunit Das, Bernard R. Bendok, Christopher C. Getch, Issam A. Awad, and H. Hunt Batjer
Stroke remains the leading cause of disability in adults and the third leading cause of death in the US. Carotid artery (CA) occlusive disease is the primary pathophysiological source of 10 to 20% of all strokes. Carotid endarterectomy (CEA) has been shown to reduce the risk of stroke in patients with both symptomatic and asymptomatic extracranial CA stenosis. Carotid artery angioplasty and stent placement has recently emerged as an alternative to CEA for primary and secondary prevention of stroke related to CA stenosis. With the advent of the embolic protection device, the safety of CA angioplasty and stent placement has approached, if not surpassed, that of CEA. In particular, the former has come to be considered as a first-line therapy in the management of CA stenotic disease in individuals at high risk for complications related to surgical intervention. Preliminary data from multiple registries have demonstrated that CA angioplasty and stent placement is an effective means of treating CA stenosis. The results of the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy trial have demonstrated that this modality has a significant role in the management of CA disease in symptomatic and asymptomatic patients with risk factors for high rates of surgery-related morbidity or mortality. With the completion of the Carotid Revascularization Endarterectomy versus Stent Trial, the role of CA angioplasty and stent placement in the prevention of stroke in all individuals with significant CA stenosis should be better demarcated. This treatment modality promises to assume a central role in stroke prophylaxis in patients with CA disease who are at high risk for complications related to surgery.
Sunit Das, Aruna Ganju, Robert L. Tiel, and David G. Kline
✓Tumors of the brachial plexus are relatively rare and present a clinical challenge for the neurosurgeon. The management of these tumors therefore requires not only an understanding of the complex anatomy of the brachial plexus but also an appreciation of the appropriate surgical approach to the various tumors that may be encountered. Over a 30-year period (1969–1999), 226 patients with brachial plexus tumors were evaluated and surgically treated by the senior authors (R.L.T., D.G.K.). In the present paper they review the most common benign and malignant brachial plexus tumors and discuss management and surgical principles established through their experience at the Louisiana State University Health Sciences Center.
Sunit Das, James P. Chandler, Ania Pollack, Eileen H. Biggio, Leslie Diaz, Jeffrey J. Raizer, and H. Hunt Batjer
✓ The authors describe an oligodendroglioma of the pineal region in a 59-year-old woman. The patient presented with intermittent confusion, memory disturbance, and headache associated with a cystic pineal region mass demonstrated on magnetic resonance imaging. Gross-total resection was performed via a suboccipital supratentorial approach. Pathological and genetic evaluation showed the tumor to be an anaplastic oligodendroglioma. Although the spectrum of tumors arising within the region of the pineal gland is broad, to the authors’ knowledge this is the first report of an oligodendroglioma occurring in this area.
Sunit Das, Kenji Muro, Stewart Goldman, Veena Rajaram, and Arthur J. DiPatri Jr.
✓ Teratomas, a group of nongerminomatous germ cell tumors, account for 3% of all childhood tumors. These unusual lesions reproduce the cellular and structural phenotypic traits associated with the three classic germ layers in inappropriate places in the body and often retain an embryonal character. These immature cells can differentiate into more malignant neoplasms. An intracranial location for this lesion type is rare. The authors describe the case of a 2-year-old boy with a teratoma of the posterior fossa that had partially differentiated into a medulloblastoma.
Timothy R. Smith, M. Maher Hulou, Sandra C. Yan, David J. Cote, Brian V. Nahed, Maya A. Babu, Sunit Das, William B. Gormley, James T. Rutka, Edward R. Laws Jr., and Robert F. Heary
Recent studies have examined the impact of perceived medicolegal risk and compared how this perception impacts defensive practices within the US. To date, there have been no published data on the practice of defensive medicine among neurosurgeons in Canada.
An online survey containing 44 questions was sent to 170 Canadian neurosurgeons and used to measure Canadian neurosurgeons’ perception of liability risk and their practice of defensive medicine. The survey included questions on the following domains: surgeon demographics, patient characteristics, type of physician practice, surgeon liability profile, policy coverage, defensive behaviors, and perception of the liability environment. Survey responses were analyzed and summarized using counts and percentages.
A total of 75 neurosurgeons completed the survey, achieving an overall response rate of 44.1%. Over one-third (36.5%) of Canadian neurosurgeons paid less than $5000 for insurance annually. The majority (87%) of Canadian neurosurgeons felt confident with their insurance coverage, and 60% reported that they rarely felt the need to practice defensive medicine. The majority of the respondents reported that the perceived medicolegal risk environment has no bearing on their preferred practice location. Only 1 in 5 respondent Canadian neurosurgeons (21.8%) reported viewing patients as a potential lawsuit. Only 4.9% of respondents would have selected a different career based on current medicolegal risk factors, and only 4.1% view the cost of annual malpractice insurance as a major burden.
Canadian neurosurgeons perceive their medicolegal risk environment as more favorable and their patients as less likely to sue than their counterparts in the US do. Overall, Canadian neurosurgeons engage in fewer defensive medical behaviors than previously reported in the US.
Melanie A. Morrison, Fred Tam, Marco M. Garavaglia, Laleh Golestanirad, Gregory M. T. Hare, Michael D. Cusimano, Tom A. Schweizer, Sunit Das, and Simon J. Graham
A computerized platform has been developed to enhance behavioral testing during intraoperative language mapping in awake craniotomy procedures. The system is uniquely compatible with the environmental demands of both the operating room and preoperative functional MRI (fMRI), thus providing standardized testing toward improving spatial agreement between the 2 brain mapping techniques. Details of the platform architecture, its advantages over traditional testing methods, and its use for language mapping are described. Four illustrative cases demonstrate the efficacy of using the testing platform to administer sophisticated language paradigms, and the spatial agreement between intraoperative mapping and preoperative fMRI results. The testing platform substantially improved the ability of the surgeon to detect and characterize language deficits. Use of a written word generation task to assess language production helped confirm areas of speech apraxia and speech arrest that were inadequately characterized or missed with the use of traditional paradigms, respectively. Preoperative fMRI of the analogous writing task was also assistive, displaying excellent spatial agreement with intraoperative mapping in all 4 cases. Sole use of traditional testing paradigms can be limiting during awake craniotomy procedures. Comprehensive assessment of language function will require additional use of more sophisticated and ecologically valid testing paradigms. The platform presented here provides a means to do so.