Stents have come to be well-known devices and are being used widely in numerous branches of medicine. It is intriguing that the word “stent” actually derives from the name of a dentist, Charles Stent, who developed a material to obtain dental impressions. There are numerous other theories as to the origin of the word and how its use has been extended to various fields in medicine. The origin of intravascular stenting took place as early as 1912, but it was not until Charles Dotter reinvented the wheel in 1969 that further development took place in the technology and techniques of stenting. Intracranial stenting is a relatively new and rapidly developing field that came into being not more than 12 years ago. The authors describe the life and works of Charles Stent, discuss the possible origins of the word stent, and discuss how intravascular and intracranial stenting came into existence.
Sudheer Ambekar and Anil Nanda
Sudheer Ambekar, Brandon G. Gaynor, Eric C. Peterson, and Mohamed Samy Elhammady
Dural arteriovenous fistulas (DAVFs) are complex lesions consisting of abnormal connections between meningeal arteries and dural venous sinuses and/or cerebral veins. The goal of treatment is surgical or endovascular occlusion of the fistula or fistulous nidus or at least the disconnection of the feeding vessels and the draining veins. Delayed angiographic data on previously embolized dural fistulas is lacking. The authors report their experience and the long-term angiographic results with embolization of intracranial DAVF using Onyx.
All cases of DAVF treated primarily with Onyx at the authors’ institution from 2006 to 2013 were retrospectively reviewed. Patient demographics, fistula characteristics, embolization details, and angiographic follow-up were analyzed.
Fifty-eight patients with DAVFs were treated during the study period. Twenty-two patients were treated with open surgery with or without prior embolization. Thirty-six patients were treated with embolization alone, of whom 26 underwent an attempt at curative embolization and are the subject of this review. All but 2 of these patients were treated in a single session. Angiographic “cure” was achieved in all cases following treatment. Follow-up angiography was performed in 21 patients at a mean of 14 months after treatment (range 2–39 months). Asymptomatic angiographic recurrence of the fistula was evident in 3 of the 21 patients (14.3%). On reviewing the procedural angiograms of the cases in which the DAVFs recurred, it was observed that the Onyx cast did not reach the venous portion in 1 case, whereas it did reach the vein in the other 2 cases.
Recurrence following initial angiographic cure of DAVF is not uncommon. Incomplete penetration of the embolic material into the proximal portion of the venous outlet may lead to delayed recurrence. Long-term angiographic follow-up is highly recommended.
Shyamal C. Bir, Sudheer Ambekar, Sunil Kukreja, and Anil Nanda
Julius Caesar Arantius is one of the pioneer anatomists and surgeons of the 16th century who discovered the different anatomical structures of the human body. One of his prominent discoveries is the hippocampus. At that time, Arantius originated the term hippocampus, from the Greek word for seahorse (hippos [“horse”] and kampos [“sea monster”]). Arantius published his description of the hippocampus in 1587, in the first chapter of his work titled De Humano Foetu Liber. Numerous nomenclatures of this structure, including “white silkworm,” “Ammon's horn,” and “ram's horn” were proposed by different scholars at that time. However, the term hippocampus has become the most widely used in the literature.
Anil Nanda, Sudheer Ambekar, Vijayakumar Javalkar, and Mayur Sharma
Tuberculum sellae meningiomas (TSMs) and diaphragma sellae meningiomas (DSMs) are challenging lesions to treat due to their proximity to neurovascular structures.
The authors reviewed the medical records of patients who underwent surgical excision of TSMs and DSMs from 1990 to 2013. They also describe the technical strategies used to minimize injury to the optic apparatus, vascular structures, and pituitary stalk.
Twenty-four patients with TSM and 6 patients with DSM were included in the study. Seventy percent of the tumors were large (≥ 5 cm). The pterional approach was employed in most cases. Optic canal involvement was observed in 4 patients. Twenty-one patients (70%) had visual dysfunction before surgery. At follow-up (median 18 months), visual improvement was noted in 10 (47.6%) of 21 patients. Gross-total excision was achieved in 22 patients (91.6%) with TSM and 5 (83.3%) with DSM. At last follow-up, 28 patients (93.3%) had a Glasgow Outcome Scale score of 5. There were no deaths in this series.
Tuberculum and diaphragma sellae meningiomas present a unique subset of tumors due to their location. They can be safely excised with minimal morbidity and mortality using microsurgical techniques. Attention to technical details during surgery leads to greater respectability and superior visual outcome.
Sunil Kukreja, Sudheer Ambekar, Anthony Hunkyun Sin, and Anil Nanda
Reports of myxopapillary ependymomas (MPEs) of the spinal cord in pediatric patients are scarce. In the literature, various authors have shared their experiences with small groups of patients, which makes it difficult to create a consensus regarding the treatment approach for spinal MPEs in young patients. The aim of this study was to perform a survival analysis of patients in the first 2 decades of life whose cases were selected from the published studies, and to examine the influence of various factors on outcomes.
A comprehensive search of studies published in English was performed on PubMed. Patients whose age was ≤ 20 years were included for integrative analysis. Information about age, treatment characteristics, critical events (progression, recurrence, and death), time to critical events, and follow-up duration was recorded. The degree of association of the various factors with the survival outcome was calculated by using Kaplan-Meier estimator and Cox proportional hazard model techniques.
A total of 95 patients were included in the analysis. The overall rate of recurrence (RR) was 34.7% (n = 33), with a median time to recurrence of 36 months (range 2–100 months). Progression-free survival (PFS) and overall survival rates at 5 years were 73.7% and 98.9%, respectively. Addition of radiotherapy (RT) following resection significantly improved PFS (log-rank test, p = 0.008). In patients who underwent subtotal resection (STR), administering RT (STR + RT) improved outcome with the lowest failure rates (10.3%), superior to patients who underwent gross-total resection (GTR) alone (RR 43.1%; log-rank test, p < 0.001). Addition of RT to patients who underwent GTR was not beneficial (log-rank test, p = 0.628). In patients who had disseminated tumor at presentation, adjuvant RT controlled the disease effectively. High-dose RT (≥ 50 Gy) did not change PFS (log-rank test, p = 0.710).
Routine inclusion of RT in the treatment protocol for spinal MPEs in young patients should be considered. Complete resection is always the goal of tumor resection. However, when complete resection does not seem to be possible in complex lesions, RT should be used as an adjunct to avoid aggressive resection and to minimize inadvertent injury to the surrounding neural tissues. High-dose RT (≥ 50 Gy) did not provide additional survival benefits, although this association needs to be evaluated by prospective studies.
Sunil Kukreja, Sudheer Ambekar, Mayur Sharma, and Anil Nanda
The authors report the case of a spinal intradural schwannoma presenting with intracranial subarachnoid hemorrhage (SAH). Cerebral angiography did not show any intracranial lesion; however, MRI revealed two separate tumors in the lower segment of the spinal cord. The proximal lesion arising from the conus medullaris was well circumscribed and homogeneously enhanced, whereas the tumor in the cauda equina revealed hemorrhagic signals on MRI. This case also illustrates an unusual presentation of intracranial SAH simultaneously with intratumoral hemorrhage in a spinal cord schwannoma. The absence of hemorrhagic changes in the lesion arising proximal to the cauda equina region supports the mechanical theory proposed for the pathogenesis of hemorrhagic complications in spinal cord tumors.
Anil Nanda and Sudheer Ambekar
This video describes the classic retrosigmoid approach for the resection of petroclival lesions. In this procedure, a careful dissection of the tumor within the arachnoid plane from the neurovascular structures is described. The key steps in the procedure are outlined, and include positioning, tumor devascularization, decompression, dissection from lower cranial nerves, IV, V cranial nerves and the VII-VIII complex and from the brainstem and closure of the dura, bone flap and the incision.
The video can be found here: http://youtu.be/DmutL7dBOxI.
Venkatesh S. Madhugiri, Sudheer Ambekar, Shane F. Strom, and Anil Nanda
The volume of scientific literature doubles approximately every 7 years. The coverage of this literature provided by online compendia is variable and incomplete. It would hence be useful to identify “core” journals in any field and validate whether the h index and impact factor truly identify the core journals in every subject. The core journals in every medical specialty would be those that provide a current and comprehensive coverage of the science in that specialty. Identifying these journals would make it possible for individual physicians to keep abreast of research and clinical progress.
The top 10 neurosurgical journals (on the basis of impact factor and h index) were selected. A database of all articles cited in the reference lists of papers published in issues of these journals published in the first quarter of 2012 was generated. The journals were ranked based on the number of papers cited from each. This citation rank list was compared with the h index and impact factor rank lists. The rank list was also examined to see if the concept of core journals could be validated for neurosurgical literature using Bradford's law.
A total of 22,850 papers spread across 2522 journals were cited in neurosurgical literature over 3 months. Although the top 10 journals were the same, irrespective of ranking criterion (h index, impact factor, citation ranking), the 3 rank lists were not congruent. The top 25% of cited articles obeyed the Bradford distribution; beyond this, there was a zone of increased scatter. Six core journals were identified for neurosurgery.
The core journals for neurosurgery were identified to be Journal of Neurosurgery, Neurosurgery, Spine, Acta Neurochirurgica, Stroke, and Journal of Neurotrauma. A list of core journals could similarly be generated for every subject. This would facilitate a focused reading to keep abreast of current knowledge. Collated across specialties, these journals could depict the current status of medical science.
Shyamal C. Bir, Sudheer Ambekar, Christina Notarianni, and Anil Nanda
In the 19th century, Dr. Odilon Marc Lannelongue was a pioneering French surgeon who introduced a surgical technique for the treatment of craniosynostosis. In 1890, Dr. Lannelongue performed correction of sagittal synostosis by strip craniectomy. From his procedure, multiple techniques have been developed and endorsed for this condition, ranging from simple suturectomies to extensive calvarial vault remodeling. In addition, even today, endoscopically aided strip craniectomy is performed as a surgical treatment of craniosynostosis. This article describes the life and works of the surgeon who revolutionized the management of craniosynostosis.
Mayur Sharma, Sudheer Ambekar, Bharat Guthikonda, Jessica Wilden, and Anil Nanda
The aim of this study was to analyze the incidence of adverse outcomes, complications, inpatient mortality, length of hospital stay, and the factors affecting them between academic and nonacademic centers after deep brain stimulation (DBS) surgery for Parkinson's disease (PD). The authors also analyzed the impact of various factors on the total hospitalization charges after this procedure.
This is a retrospective cohort study using the Nationwide Inpatient Sample (NIS) from 2006 to 2010. Various patient and hospital variables were analyzed from the database. The adverse discharge disposition and the higher cost of hospitalization were taken as the dependent variables.
A total of 2244 patients who underwent surgical treatment for PD were identified from the database. The mean age was 64.22 ± 9.8 years and 68.7% (n = 1523) of the patients were male. The majority of the patients was discharged to home or self-care (87.9%, n = 1972). The majority of the procedures was performed at high-volume centers (64.8%, n = 1453), at academic institutions (85.33%, n = 1915), in urban areas (n = 2158, 96.16%), and at hospitals with a large bedsize (86.6%, n = 1907) in the West or South. Adverse discharge disposition was more likely in elderly patients (OR > 1, p = 0.011) with high comorbidity index (OR 1.508 [95% CI 1.148–1.98], p = 0.004) and those with complications (OR 3.155 [95% CI 1.202–8.279], p = 0.033). A hospital with a larger annual caseload was an independent predictor of adverse discharge disposition (OR 3.543 [95% CI 1.781–7.048], p < 0.001), whereas patients treated by physicians with high case volumes had significantly better outcomes (p = 0.006). The median total cost of hospitalization had increased by 6% from 2006 through 2010. Hospitals with a smaller case volume (OR 0.093, p < 0.001), private hospitals (OR 11.027, p < 0.001), nonteaching hospitals (OR 3.139, p = 0.003), and hospitals in the West compared with hospitals in Northeast and the Midwest (OR 1.885 [p = 0.033] and OR 2.897 [p = 0.031], respectively) were independent predictors of higher hospital cost. The mean length of hospital stay decreased from 2.03 days in 2006 to 1.55 days in 2010. There was no difference in the discharge disposition among academic versus nonacademic centers and rural versus urban hospitals (p > 0.05).
Elderly female patients with nonprivate insurance and high comorbidity index who underwent surgery at low-volume centers performed by a surgeon with a low annual case volume and the occurrence of postoperative complications were correlated with an adverse discharge disposition. High-volume, government-owned academic centers in the Northeast were associated with a lower cost incurred to the hospitals. It can be recommended that the widespread availability of this procedure across small, academic centers in rural areas may not only provide easier access to the patients but also reduces the total cost of hospitalization.