Stereotactic radiosurgery and the linear accelerator: accelerating electrons in neurosurgery
Maryam Rahman, Gregory J. A. Murad, and J Mocco
Stereotactic neurosurgery has a rich history, beginning with the first stereotactic frame described by Horsley and Clarke in 1908. It is now widely used for delivery of radiation, surgical targeting of electrodes, and resection to treat tumors, epilepsy, vascular malformations, and pain syndromes. These treatments are now available due to the pioneering efforts of neurosurgeons and scientists in the beginning of the 20th century. Their efforts focused on the development of stereotactic instruments for accurate lesion targeting. In this paper, the authors review the history of the stereotactic apparatus in the early 20th century, with a focus on the fascinating people key to its development.
E. Sander Connolly Jr.
Maryam Rahman, Gregory J. Velat, Brian L. Hoh, and J Mocco
Cerebral venous sinus thrombosis (CVST) is an increasingly diagnosed disease with a wide range of symptoms, ranging from a mild headache to cerebral herniation. A potentially devastating syndrome, CVST has been associated with a mortality rate of 6–10%. In prospective studies, the overall rate of death and dependency from CVST ranges from 8.8 to 44.4%. Systemic anticoagulation remains the first-line treatment. However, a percentage of patients deteriorate despite medical therapy. These cases have resulted in the development of thrombolysis or endovascular treatment for CVST. Initial reports of the use of endovascular treatment of CVST have been promising. However, enthusiasm for the use of endovascular thrombolysis and thrombectomy should be tempered by an understanding of possible risks such as intracerebral hemorrhage and/or vessel dissection. The authors review the literature regarding endovascular treatment of CVST with a description of the chemical and mechanical thrombolytic techniques.
Kyle M. Fargen, Dan Neal, Spiros L. Blackburn, Brian L. Hoh, and Maryam Rahman
The Agency for Healthcare Research and Quality patient safety indicators (PSIs) and the Centers for Medicare and Medicaid Services hospital-acquired conditions (HACs) are publicly reported quality metrics linked directly to reimbursement. The occurrence of PSIs and HACs is associated with increased mortality and hospital costs after stroke. The relationship between insurance status and PSI and HAC rates in hospitalized patients treated for acute ischemic stroke was determined using the Nationwide Inpatient Sample (NIS) database.
The NIS was queried for all hospitalizations involving acute ischemic stroke between 2002 and 2011. The rate of each PSI and HAC was determined by searching the hospital records for ICD-9 codes. The SAS statistical software package was used to calculate rates and perform multivariable analyses to determine the effects of patient variables on the probability of developing each indicator.
The NIS query revealed 1,507,336 separate patient admissions that had information on both primary payer and hospital teaching status. There were 227,676 PSIs (15.1% of admissions) and 42,841 HACs reported (2.8%). Patient safety indicators occurred more frequently in Medicaid/self-pay/no-charge patients (19.1%) and Medicare patients (15.0%) than in those with private insurance (13.6%; p < 0.0001). In a multivariable analysis, Medicaid, self-pay, or nocharge patients had significantly longer hospital stays, higher mortality, and worse outcomes than those with private insurance (p < 0.0001).
Insurance status is an independent predictor of patient safety events after stroke. Private insurance is associated with lower mortality, shorter lengths of stay, and improved clinical outcomes.
Kyle M. Fargen, Maryam Rahman, Dan Neal, and Brian L. Hoh
The Agency for Healthcare Research and Quality (AHRQ) patient safety indicators (PSIs) and the Centers for Medicare and Medicaid Services hospital-acquired conditions (HACs) are metrics used to gauge the quality of health care provided by health care institutions. The PSIs and HACs are publicly reported metrics and are directly linked to reimbursement for services. To better understand the prevalence of these adverse events in hospitalized patients treated for unruptured cerebral aneurysms, the authors determined the incidence rates of PSIs and HACs among patients with a diagnosis of unruptured aneurysm in the Nationwide Inpatient Sample (NIS) database.
The NIS, part of the AHRQ's Healthcare Cost and Utilization Project, was queried for all hospitalizations between 2002 and 2010 involving coiling or clipping of unruptured cerebral aneurysms. The incidence rate for each PSI and HAC was determined by searching the hospital records for ICD-9 codes. The SAS statistical software package was used to calculate incidences and perform multivariate analyses to determine the effects of patient variables on the probability of each indicator developing.
There were 54,589 hospitalizations involving unruptured cerebral aneurysms in the NIS database for the years 2002–2010; 8314 patients (15.2%) underwent surgical clipping and 9916 (18.2%) were treated with endovascular coiling. One thousand four hundred ninety-two PSI and HAC events occurred among the 8314 patients treated with clipping; at least 1 PSI or HAC occurred in 14.6% of these patients. There were 1353 PSI and HAC events among the 9916 patients treated with coiling; at least 1 PSI or HAC occurred in 10.9% of these patients. Age, sex, and comorbidities had statistically significant associations with an adverse event. Compared with the patients having no adverse event, those having at least 1 PSI during their hospitalizations had significantly longer hospital stays (p < 0.0001), higher hospital costs (p < 0.0001), and higher mortality rates (p < 0.0001).
These results estimate baseline national rates of PSIs and HACs in patients with unruptured cerebral aneurysms. These data may be used to gauge individual institutional quality of care and patient safety metrics in comparison with national data.
Kyle M. Fargen, Dan Neal, Maryam Rahman, and Brian L. Hoh
The Agency for Healthcare Research and Quality (AHRQ) patient safety indicators (PSIs) and the Centers for Medicare and Medicaid Services hospital-acquired conditions (HACs) are publicly reported metrics used to gauge the quality of health care provided by health care institutions. To better understand the prevalence of these events in hospitalized patients treated for ruptured cerebral aneurysms, the authors determined the incidence rates of PSIs and HACs among patients with a diagnosis of subarachnoid hemorrhage and procedure codes for either coiling or clipping in the Nationwide Inpatient Sample database.
The authors queried the Nationwide Inpatient Sample database, part of the AHRQ's Healthcare Cost and Utilization Project, for all hospitalizations between 2002 and 2010 involving coiling or clipping of ruptured cerebral aneurysms. The incidence rate of each PSI and HAC was determined by searching the hospital records for ICD-9 codes. The authors used the SAS statistical software package to calculate incidence rates and perform multivariate analyses to determine the effects of patient variables on the probability of developing each indicator.
There were 62,972 patient admissions with a diagnosis code of subarachnoid hemorrhage between the years 2002 and 2010; 10,274 (16.3%) underwent clipping and 8248 (13.1%) underwent endovascular coiling. A total of 6547 PSI and HAC events occurred within the 10,274 patients treated with clipping; at least 1 PSI or HAC occurred in 47.9% of these patients. There were 5623 total PSI and HAC events among the 8248 patients treated with coils; at least 1 PSI or HAC occurred in 51.0% of coil-treated patients. Age, sex, comorbidities, hospital size, and hospital type had statistically significant associations with indicator occurrence. Compared with patients without events, those treated by either clipping or coiling and had at least 1 PSI during their hospitalization had significantly longer lengths of stay (p < 0.001), higher hospital costs (p < 0.001), and higher in-hospital mortality rates (p < 0.001).
These results estimate baseline national rates of PSIs and HACs in patients treated for ruptured cerebral aneurysms. These data may be used to gauge individual institutional quality of care and patient safety metrics in comparison with national data.
Maryam Rahman, Gregory J. A. Murad, Frank Bova, William A. Friedman, and J Mocco
The search for efficacious, minimally invasive neurosurgical treatment has led to the development of the operating microscope, endovascular treatment, and endoscopic surgery. One of the most minimally invasive and exciting discoveries is the use of targeted, high-dose radiation for neurosurgical disorders. Radiosurgery is truly minimally invasive, delivering therapeutic energy to an accurately defined target without an incision, and has been used to treat a wide variety of pathological conditions, including benign and malignant brain tumors, vascular lesions such as arteriovenous malformations, and pain syndromes such as trigeminal neuralgia. Over the last 50 years, a tremendous amount of knowledge has been garnered, both about target volume and radiation delivery. This review covers the intense study of these concepts and the development of linear accelerators to deliver stereotactic radiosurgery. The fascinating history of stereotactic neurosurgery is reviewed, and a detailed account is given of the development of linear accelerators and their subsequent modification for radiosurgery.
Kristin J. Weaver, Matthew McCord, Dan Neal, Frank Bova, Didier Rajon, Alfredo Quinones-Hinojosa, and Maryam Rahman
Many colloid cyst patients present with obstructive hydrocephalus that resolves after resection of the cyst. However, a proportion of patients with these cysts will require cerebrospinal fluid shunting after tumor resection, despite resolution of the obstruction at the foramina of Monro. The goal of this study was to determine if colloid cyst size or preoperative ventricular volume predicted the need for postresection shunting.
In a retrospective study design, ICD-9 codes 742.2 (colloid cyst) and 348.0 (brain cyst) were used to identify patients who had undergone resection of a colloid cyst at the University of Florida over the last 20 years. Preoperative imaging (CT or MRI) with a stereotactic software program developed at the University of Florida was used to measure volumes of the colloid cyst and the lateral ventricles. The relationships among ventricular volume, colloid cyst volume, and postoperative shunting were analyzed.
The number of patients included in the study was 67, and their mean age was 37.7 years. Forty percent of the patients were female. Overall, 49.2% of the patients had a transcallosal approach, 35.8% a transcortical approach, and 14.9% an endoscope-assisted surgery. Mean preoperative ventricular volume was 76.5 cc in patients who never received a ventriculoperitoneal shunt (VPS) and 98.1 cc in those who were eventually treated with a VPS (p = 0.305). Patients with a postoperative VPS had an initial mean colloid cyst volume of 1.8 cc compared with 0.9 cc in patients without a VPS postoperatively (p = 0.019). Patients with colloid cysts larger than 0.6 cc (1-cm diameter) had a 12.8 increased odds of needing a VPS postoperatively (95% CI 1.81–275).
Larger colloid cysts are associated with an increased need for postresection shunting independent of preoperative ventricular size. Prospective studies of patients with colloid cysts are necessary to further identify risks of permanent hydrocephalus.
Tyler Lazaro, Visish M. Srinivasan, Maryam Rahman, Ashok Asthagiri, Garni Barkhoudarian, Lola B. Chambless, Peter Kan, Ganesh Rao, Brian V. Nahed, and Akash J. Patel
Neurosurgical education in the US has changed significantly as a consequence of the novel coronavirus (COVID-19) pandemic. Institutional social distancing requirements have resulted in many neurosurgical programs utilizing video conferencing for educational activities. However, it is unclear how or if these practices should continue after the pandemic. The objective of this study was to characterize virtual education in neurosurgery and understand how it should be utilized after COVID-19.
A 24-question, 3-part online survey was administered anonymously to all 117 US neurosurgical residency programs from May 15, 2020, to June 15, 2020. Questions pertained to the current use of virtual conferencing, preferences over traditional conferences, and future inclinations. The Likert scale (1 = strongly disagree, 3 = neutral, 5 = strongly agree) was used. Comparisons were calculated using the Mann-Whitney U-test. Statistical significance was set at 0.05.
One-hundred eight responses were recorded. Overall, 38 respondents (35.2%) were attendings and 70 (64.8%) were trainees. Forty-one respondents (38.0%) indicated attending 5–6 conferences per week and 70 (64.8%) attend national virtual conferences. When considering different conference types, there was no overall preference (scores < 3) for virtual conferences over traditional conferences. In regard to future use, respondents strongly agreed that they would continue the practice at some capacity after the pandemic (median score 5). Overall, respondents agreed that virtual conferences would partially replace traditional conferences (median score 4), whereas they strongly disagreed with the complete replacement of traditional conferences (median score 1). The most common choices for the partial replacement of tradition conferences were case conferences (59/108, 55%) and board preparation (64/108, 59%). Lastly, there was a significant difference in scores for continued use of virtual conferencing in those who attend nationally sponsored conferences (median score 5, n = 70) and those who do not (median score 4, n = 38; U = 1762.50, z = 2.97, r = 0.29, p = 0.003).
Virtual conferences will likely remain an integral part of neurosurgical education after the COVID-19 pandemic has abated. Across the country, residents and faculty report a preference for continued use of virtual conferencing, especially virtual case conferences and board preparation. Some traditional conferences may even be replaced with virtual conferences, in particular those that are more didactic. Furthermore, nationally sponsored virtual conferences have a positive effect on the preferences for continued use of virtual conferences.