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Amitabha Chanda and Anil Nanda

Object. An anatomical study in which measurements were obtained was undertaken to demonstrate that the orbitozygomatic transcavernous—transclinoidal approach provides excellent exposure of the trunk of the basilar artery (BA) and its bifurcation.

Methods. Bilateral stepwise dissections were performed on 10 fixed cadaver heads with the aid of × 3 to × 40 magnifications. A frontotemporal craniotomy was made, followed by an orbitozygomatic osteotomy. After the dura mater had been opened, the sylvian fissure was widely separated. The anteromedial triangle of the cavernous sinus was opened to mobilize the internal carotid artery medially. The sella turcica and the dorsum sellae were exposed. The posterior clinoid process and the dorsum sellae were drilled to expose a length of BA that included its bifurcation. Measurements were obtained following the frontotemporal craniotomy, orbitozygomatic osteotomy, and drilling of the posterior clinoid process to quantify the exposures provided by these procedures.

Excellent exposure of the trunk of the BA and its bifurcation was achieved. The structures in the interpeduncular cistern and the prepontine cistern were also exposed. There was an average gain of a 13.4-mm-long segment of the BA, which in some surgeries can be invaluable. The angle of exposure that was achieved with the BA bifurcation located at the apex increased markedly. Moreover, this method widened the oculomotor nerve—carotid artery corridor for easier access to the BA bifurcation region.

Conclusions. This approach combines the advantages granted by most conventional approaches to aneurysms of the BA bifurcation. The approach is suitable for aneurysms situated at a high, normal, or low position on the BA bifurcation. It exposes a sufficient length of the BA trunk to place a temporary clip.

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David E. Connor Jr. and Anil Nanda

In the 1970s, the membrane of Liliequist became the accepted name for a small band of arachnoid membrane separating the interpeduncular and chiasmatic cisterns, making it one of the most recent of the universally accepted medical eponyms. The story of its discovery, however, cannot be told without a thorough understanding of the man responsible and his contribution to the growth of a specialty. Bengt Liliequist lived during what many would consider the Golden Age of neuroradiology. With his colleagues at the Serafimer Hospital in Stockholm, he helped set the standard for appropriate imaging of the CNS and contributed to more accurate localization of intracerebral as well as spinal lesions. The pneumoencephalographic discovery of the membrane that was to bear his name serves merely as a starting point for a career that spanned five decades and included the defense of two separate doctoral theses, the last of which occurred after his 80th birthday. Although the recognition of neuroradiology as a subspecialty did not occur in his home country of Sweden until after his retirement, and technological progress saw the obsolescence of the procedure that he had mastered, Dr. Liliequist's accomplishments and his contributions to the current understanding of neuroanatomy merit our continued praise.

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Richard Menger, Austin Menger and Anil Nanda


Multiple studies have illustrated that rugby headgear offers no statistically significant protection against concussions. However, there remains concern that many players believe rugby headgear in fact does prevent concussions. Further investigation was undertaken to illustrate that misconceptions about concussion prevention and rugby headgear may lead to an increase in aggressive play.


Data were constructed by Internet survey solicitation among United States collegiate rugby players across 19 teams. Initial information given was related to club, age, experience, use of headgear, playing time, whether the rugger played football or wrestling in high school, and whether the player believed headgear prevented concussion. Data were then constructed as to whether wearing headgear would increase aggressive playing style secondary to a false sense of protection.


A total of 122 players responded. All players were male. The average player was 19.5 years old and had 2.7 years of experience. Twenty-three of 122 players (18.9%) wore protective headgear; 55.4% of players listed forward as their primary position. Overall, 45.8% (55/120) of players played 70–80 minutes per game, 44.6% (54/121) played football or wrestled in high school, 38.1% (45/118) believed headgear prevented concussions, and 42.2% (51/121) stated that if they were using headgear they would be more aggressive with their play in terms of running or tackling. Regression analysis illustrated that those who believed headgear prevented concussions were or would be more likely to engage in aggressive play (p = 0.001).


Nearly 40% of collegiate rugby players surveyed believed headgear helped to prevent concussions despite no scientific evidence that it does. This misconception about rugby headgear could increase aggressive play. Those who believed headgear prevented concussion were, on average, 4 times more likely to play with increased aggressive form than those who believed headgear did not prevent concussions (p = 0.001). This can place all players at increased risk without providing additional protection. Further investigation is warranted to determine if headgear increases the actual measured incidence of concussion among rugby players in the United States.

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Nasser Mohammed, Devi Patra and Anil Nanda


Magnetic resonance–guided focused ultrasound (MRgFUS) is a novel technique that uses high-intensity focused ultrasound to achieve target ablation. Like a lens focusing the sun’s rays, the ultrasound waves are focused to generate heat. This therapy combines the noninvasiveness of Gamma Knife thalamotomy and the real-time ablation of deep brain stimulation with acceptable complication rates. The aim of this study was to analyze the overall outcomes and complications of MRgFUS in the treatment of essential tremor (ET).


A meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was made by searching PubMed, Cochrane library database, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL). Patients with the diagnosis of ET who were treated with MRgFUS were included in the study. The change in the Clinical Rating Scale for Tremor (CRST) score after treatment was analyzed. The improvement in disability was assessed with the Quality of Life in Essential Tremor Questionnaire (QUEST) score. The pooled data were analyzed by the DerSimonian-Laird random-effects model. Tests for bias and heterogeneity were performed.


Nine studies with 160 patients who had ET were included in the meta-analysis. The ventral intermediate nucleus was the target in 8 of the studies. The cerebellothalamic tract was targeted in 1 study. There was 1 randomized controlled trial, 6 studies were retrospective, and 2 were prospective. The mean number of sonications given in various studies ranged from 11 ± 3.2 to 22.5 ± 7.5 (mean ± SD). The maximum delivered energy ranged from 10,320 ± 4537 to 14,497 ± 6695 Joules. The mean of peak temperature reached ranged from 53°C ± 2.3°C to 62.0°C ± 2.5°C. On meta-analysis with the random-effects model, the pooled percentage improvements in the CRST Total, CRST Part A, CRST Part C, and QUEST scores were 62.2%, 62.4%, 69.1%, and 46.5%, respectively. Dizziness was the most common in-procedure complication, occurring in 43.4%, followed by nausea and vomiting in 26.85% (pooled percentage). At 3 months, ataxia was the most common complication, occurring in 32.8%, followed by paresthesias in 25.1% of the patients. At 12 months posttreatment, the ataxia had significantly recovered and paresthesias became the most common persisting complication, at 15.3%.


The MRgFUS therapy for ET significantly improves the CRST scores and improves the quality of life in patients with ET, with an acceptable complication rate. Therapy with MRgFUS is a promising frontier in functional neurosurgery.

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Sudheer Ambekar and Anil Nanda

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.

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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.

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Shyamal C. Bir, Piyush Kalakoti, Christina Notarianni and Anil Nanda

In the late 18th and early 19th centuries, Dr. John Howship, a pioneering British surgeon, described the clinical features and pathophysiology of various surgical disorders of the human body. His critical contributions to pediatric neurosurgery came in 1816 when he first described the features of an important childhood condition following head trauma, what he referred to as parietal bone absorption. This condition as depicted by Dr. Howship was soon to be christened by later scholars as traumatic cephalhydrocele, traumatic meningocele, leptomeningeal cyst, meningocele spuria, fibrosing osteitis, cerebrocranial erosion, and growing skull fracture. Nevertheless, the basic features of the condition as observed by Dr. Howship were virtually identical to the characteristics of the above-mentioned disorders. This article describes the life and accomplishments of Dr. Howship and his contributions to the current understanding of growing skull fracture.

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Amitabha Chanda, Donald R. Smith and Anil Nanda

Object. The authors used a modern cell saver technique to perform autotransfusion in patients undergoing instrument-assisted lumbar and/or thoracic spinal fusion, in whom significant blood loss was anticipated. The safety and benefits of this procedure as well as its cost effectiveness were analyzed.

Methods. The authors studied 50 patients who underwent lumbar and/or thoracic spinal fusion in which instrumentation was placed between January 1998 and June 2000 and in whom an estimated blood loss of 500 ml or more was expected. All surgeries were conducted by a single neurosurgeon (D.R.S.). During surgery, the Brat 2 cell saver system was used to salvage the autologous blood. The anesthesiologist and surgeon jointly decided, on the basis of hematocrit and clinical stability, whether transfusion was necessary in each patient. Various parameters (hematocrit, plasma and urine hemoglobin, platelet counts, coagulation profile, and serum bilirubin) were measured pre-, intra-, and postoperatively.

Thirty-three patients (66%) required transfusion. The mean blood loss in these patients was 1046 ml. The most important factor affecting blood loss was the number of levels fused (p < 0.0001). Only two patients required postoperative homologous transfusion. The mean decrease in hematocrit was 7.82%. The maximum reduction of platelet count was limited to 80,000/mm3. Major complications such as hemoglobinuria, coagulopathy, cardiopulmonary problems, air embolism, and major sepsis were not observed in this study.

Conclusions. Autotransfusion performed using a modern cell saver technique is safe and has many advantages over homologous transfusion. It conserves the homologous blood resources. The costs of the two modes are statistically comparable when greater than 500 ml of red blood cell transfusion is necessary.

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Prasad Vannemreddy, Gloria Caldito, Brian Willis and Anil Nanda


The purpose of this study was to determine whether cocaine use is a significant prognostic factor for outcome measures such as Hunt and Hess grade and Glasgow Outcome Scale (GOS) score among patients presenting with ruptured intracranial aneurysms (IAs).


The authors performed a MEDLINE/PubMed search for cases of ruptured IAs associated with cocaine use. Fourteen cases from the authors' experience were combined with 50 from a literature review, for a total of 64 cases associated with cocaine use. These 64 cases were compared with 65 cases without cocaine use (controls), which had been obtained from an aneurysm database. Logistic regression analysis was performed to determine significant prognostic factors for a poor Hunt and Hess grade and a poor GOS score, and a general linear model was applied to identify significant factors for these measures among cocaine users.


There were 40 women in each group. The mean age was 32.3 ± 8.1 years in the cocaine group and 49.7 ± 10.6 years in the control group; thus, patients in the cocaine group were significantly younger (p < 0.01). Cocaine was snorted in 21% of cases, smoked in 55%, and intravenously injected or taken in through a combination of routes in 24%. Fifty-one percent of cocaine users and 7.7% of nonusers presented with a poor GOS score (p < 0.01). Fifty-six percent had ictus during cocaine abuse. At the end of a 30-day follow-up, 51% of the patients in the cocaine group had a good GOS score compared with 92% in the control group (p < 0.01). Controlling for the effects of other significant factors, cocaine use had a significant effect on Hunt and Hess grade (p < 0.03) and GOS score (p < 0.01). The odds of having a poor Hunt and Hess grade among cocaine users were 4.2 times greater than those in nonusers, and the odds of having a poor GOS score among cocaine users were 38.8 times greater.


Aneurysms were significantly smaller and ruptured at a younger age among cocaine users compared with nonusers. Although the poor clinical grade was not significantly different between the 2 groups, outcome was significantly worse in cocaine users.