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Erratum: Isadore Max Tarlov (1905–1977) and the controversial Tarlov cyst: historical perspective

Anil Nanda

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Anatomical study of the orbitozygomatic transsellar—transcavernous—transclinoidal approach to the basilar artery bifurcation

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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Skull base cerebrospinal fluid fistula

John Diaz Day and Anil Nanda

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Charles Stent and the mystery behind the word “stent”

Historical vignette

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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Lessons from the life of Asia’s first female neurosurgeon for modern neurosurgical trainees and educators worldwide

Ahmad Ozair, Vivek Bhat, and Anil Nanda

Surgical specialties, and particularly neurosurgery, have historically had and continue to have poor representation of female trainees. This is especially true of South Asia, considering the added social and cultural expectations for women in this region. Yet it was in India, with its difficult history of gender relations, that Asia’s first fully qualified female neurosurgeon, Dr. T. S. Kanaka (1932–2018), took root, flourished, and thereafter played an integral role in helping develop stereotactic and functional neurosurgery in the country. While a few biographical accounts of her exist, highlighted here are the lessons from her illustrious life for neurosurgical trainees and educators worldwide, along with the instances that exemplify those lessons, drawn from several hitherto unutilized primary sources. These lessons are consistent with the factors identified in previous systematic reviews to be contributing to gender disparities in neurosurgery. Many of the virtues that ensured her success are attributes that continue to be critical for a neurosurgical career. Additionally, the circumstances that helped Kanaka succeed have been recounted as considerations for those working to promote diversity and inclusion. Finally, her life choices and sacrifices are described, which are underexplored but relevant concerns for women in neurosurgery.

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Bengt Liliequist: life and accomplishments of a true renaissance man

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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Impact of body habitus on fluoroscopic radiation emission during minimally invasive spine surgery

Presented at the 2014 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves

Sunil Kukreja, Justin Haydel, Anil Nanda, and Anthony H. Sin

OBJECT

Minimally invasive spine surgeries (MISSs) have gained immense popularity in the last few years. Concern about the radiation exposure has also been raised. The purpose of this study was to demonstrate the impact of body habitus on the radiation emission during various MISS procedures. The authors also aim to evaluate the effect the surgeon's experience has on the amount of radiation exposure during MISS especially with regard to patient size.

METHODS

The authors conducted a retrospective analysis of 332 patients who underwent 387 MISS procedures performed at their institution from January 2010 to August 2013 by a single surgeon. The dose of radiation emission available from the fluoroscopic equipment was recorded from the electronic database. The authors analyzed mainly 3 procedure groups: microdiscectomy/decompression (MiDD, n = 211) and transforaminal lumbar interbody fusion (TLIF) either with unilateral instrumentation (UnTLIF, n = 106) or bilateral instrumentation (BiTLIF, n = 70). The patients in each procedure group were divided into 6 categories based on the WHO criteria for obesity: underweight (body mass index [BMI] < 18.50), normal (18.50–24.99), overweight (25.00–29.99), Class 1 obese (30.00–34.99), Class 2 obese (35.00– 39.99), and Class 3 obese (> 40.00).

RESULTS

Patients who underwent BiTLIF had the highest median radiation exposure (113 mGy, SD 9.44), whereas microdiscectomy required minimal exposure (12.62 mGy, SD 2.75 mGy). There was a significant correlation between radiation emission and BMI of the patients during all MISS procedures (p < 0.05). The median radiation exposure was substantially greater with larger patients (p ≤ 0.001). In the analyses within the procedure groups, radiation exposure was found to be significantly high in patients who were severely obese (Class 2 and Class 3 obesity). The radiation emission was lower during the surgeries performed in 2013 than during those performed in 2010 especially in obese patients; however, this observation was not statistically significant.

CONCLUSIONS

Body habitus of the patients has a substantial impact on radiation emission during MISS. Severe obesity (BMI ≥ 35) is associated with a significantly greater risk of radiation exposure compared with other weight categories. Surgical experience seems to be associated with lower radiation emission especially in cases in which patients have a higher BMI; however, further studies should be performed to examine this effect.

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Iatrogenic splenic injury during anterior thoracolumbar spinal surgery

Case report

Anthony Sin, Donald Smith, and Anil Nanda

✓The proximity of major abdominal structures encountered in the approach for an anterior thoracolumbar spinal operation makes patients vulnerable to potential intraoperative complications. The spleen, in particular, can be easily injured during manipulation or from being under retractors for a number of hours, although it is a rarely reported phenomenon in the literature. The authors report on a 52-year-old man who suffered a spleen laceration following anterior L1–2 corpectomy and fusion for osteomyelitis of the lumbar spine. The patient required an emergency splenectomy, but he made a full recovery.

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Autotransfusion by cell saver technique in surgery of lumbar and thoracic spinal fusion with instrumentation

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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Rugby headgear and concussion prevention: misconceptions could increase aggressive play

Richard Menger, Austin Menger, and Anil Nanda

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.