Computer-assisted surgery in medical and dental applications.

INTRODUCTION: Computer-assisted surgery (CAS) is a broad surgical methodology that utilizes computer technology to both plan and execute surgical intervention. CAS is widespread in both medicine and dentistry as it allows for minimally invasive and precise surgical procedures. Key innovations in volumetric imaging, virtual surgical planning software, instrument tracking, and robotics have assisted in facilitating the transfer of surgical plans to precise execution of surgical procedures. CAS has long been used in certain medical specialties including neurosurgery, cardiology, orthopedic surgery, otolaryngology, and interventional radiology, and has since expanded to oral and maxillofacial application, particularly for computer-assisted implant surgery. AREAS COVERED: This review provides an updated overview of the most current research for CAS in medicine and dentistry, with a focus on neurosurgery and dental implant surgery. The MEDLINE electronic database was searched and relevant original and review articles from 2005 to 2020 were included. EXPERT OPINION: Recent literature suggests that CAS performs favorably in both neurosurgical and dental implant applications. Computer-guided surgical navigation is well entrenched as standard of care in neurosurgery. Whereas static computer-assisted implant surgery has become established in dentistry, dynamic computer-assisted navigation is newly poised to trend upward in dental implant surgery.

Characteristics and career outcomes of Neurosurgery Research and Education Foundation research fellowship recipients.

OBJECTIVE: The American Association of Neurological Surgeons (AANS) Neurosurgery Research and Education Foundation (NREF) provides ongoing competitive research fellowships for residents and young investigators. The authors sought to determine the characteristics and career tracks of award recipients. METHODS: The authors analyzed characteristics and academic productivity parameters of NREF resident and young investigator awardees in the United States and Canada from 1983 to 2017. Data were extracted from the NREF database and online resources (Web of Science, NIH reporter). RESULTS: In total, 224 research grants were awarded to 31 women (14%) and 193 men (86%) from 1983 to 2017. Neuro-oncology (36%) was the most common research category. Sixty percent of awardees were in training and most resident award winners were in postgraduate year 5 (37%). Forty-nine percent of all awardees had an additional postgraduate degree (PhD 39%, Master's 10%) with a significantly higher number of PhD recipients being from Canada in comparison to any US region (p = 0.024). The Northeastern and Southeastern United States were the regions with the highest and lowest numbers of award recipients, respectively. More than one-third (40%) of awardees came from institutions that have a National Institute of Neurological Disorders and Stroke Research Education Grant (NINDS R25) for neurosurgical training. Awardees from NINDS R25-funded programs were significantly more likely to go on to receive funding from the National Institutes of Health (NIH) (40.4% vs 26.1%; p = 0.024). The majority of recipients (72%) who were no longer in training pursued fellowships, with a significant likelihood that fellowship subspecialty correlated with NREF research category (p < 0.001). Seventy-nine percent of winners entered academic neurosurgery practice, with 18% obtaining the position of chair. The median h-index among NREF winners was 11. NIH funding was obtained by 71 awardees (32%) with 36 (18%) being a principal investigator on an R01 grant from the NIH Research Project Grant Program. CONCLUSIONS: The majority of AANS/NREF research award recipients enter academics as fellowship-trained neurosurgeons, with approximately one-third obtaining NIH funding. Analysis of this unique cohort allows for identification of characteristics of academic success.

The burden of neurothrombectomy call: a multicenter prospective study.

INTRODUCTION: Neurothrombectomy frequency is increasing, and a better understanding of the neurothrombectomy call burden is needed. METHODS: Neurointerventional physicians at nine participating stroke centers prospectively recorded time requirements for all neurothrombectomy (NT) consultations over 30 consecutive 24 hour call periods. RESULTS: Data were collected from a total of 270 days of call. 214 NT consultations were reported (mean 0.79 per day), including 130 'false positive' consultations that ultimately did not lead to thrombectomy (mean 0.48 per day). 84 NT procedures were performed at the nine centers (0.32 per day, or 1 every 3 days). Most (59.8%) consultations occurred between 5pm and 7am. 30% of thrombectomy procedures resulted in delays in scheduled cases; treating physicians had to emergently travel to the hospital for 51.2% of these cases. A median of 27 min was spent on each false positive consultation and 171 min on each thrombectomy. Overall, the median physician time spent on NT responsibilities per 24 hour call period was 69 min (mean 85 min; IQR 16-135 min). CONCLUSIONS: NT consultations are frequent and often disrupt physician schedules, requiring physicians to commute in from home after hours in the majority of cases. As procedural and consultation volumes increase, it is crucial to understand the significant burden of call on neurointerventional physicians and develop strategies that reduce the potential for burnout. Importantly, this study was performed prior to the completion of the DAWN and DEFUSE3 trials; NT consultations are expected to continue to increase in the future.

Minimally invasive approach to resection of paraspinal schwannoma.

In this video, the authors demonstrate a minimally invasive approach and resection of a paraspinal schwannoma. Using an expandable retractor, the authors were able to identify important adjacent bony landmarks and hence visualize and remove this peripheral nerve sheath tumor. While a tubular retractor is commonly used for interbody fusion procedures, the location of the tumor allowed this minimally invasive approach resulting in excellent access, minimal soft-tissue injury, and a short hospital stay. The authors present this approach as a less invasive and yet effective technique for resection of otherwise difficult-to-access nerve lesions. The video can be found here: https://youtu.be/89OY5wdMB_k .

A multicenter study evaluating the frequency and time requirement of mechanical thrombectomy.

INTRODUCTION: There are few published data evaluating the incidence of mechanical thrombectomy among stroke centers or the times at which they occur. METHODS: A multicenter retrospective study was performed to identify all patients undergoing emergent thrombectomy for acute ischemic stroke during a 3-month period (June through August 2016). Consultations that did not undergo thrombectomy were not included. RESULTS: Ten institutions participated in the study. During the 92-day study period, a total of 189 patients underwent mechanical thrombectomy. The average number of procedures per hospital over the study period was 18.9 (average of 0.2 cases per day per or 75.6 cases per year). This ranged from 0.09 cases per day at the lowest volume center to 0.49 cases per day at the highest volume center. Procedures were more common on weekdays (p<0.001) and during non-work hours (p<0.001). The most common period for thrombectomy procedures was between 20:00 and 21:00 hours. The median time from notification to groin puncture was 84 min (IQR 56-145 min) and from puncture to closure was 57 min (IQR 33-80 min). The median time from imaging completion to procedural start was 52 min longer for non-work hours than during work hours (p<0.001). There were no differences in procedural length based on day of the week or time of day. CONCLUSIONS: These findings indicate that the majority of mechanical thrombectomy cases occur during non-work hours, with associated off-hours delays, which has important operational implications for hospitals implementing stroke call coverage.

Tracking Career Paths of Women in Neurosurgery.

BACKGROUND: Women represent a growing cohort of US neurosurgeons. OBJECTIVE: To describe postresidency fellowship, practice environment, and updated academic rank among female neurosurgeons. METHODS: Databases from the American Association of Neurological Surgeons (AANS) and the American Board of Neurological Surgery (ABNS) from 1964 to 2013 were reviewed for female neurosurgery residency graduates. Data on postresidency fellowships, practice environment (private vs academic), academic rank, board certification, and AANS/CNS (Congress of Neurological Surgeons) Joint Section on Women in Neurosurgery (WINS) membership were collected in 2016. Academic rank was verified from program websites and electronic correspondence. Faculty members were asked to report directorships and tenure. The AANS/CNS Joint Section on Women in Neurosurgery verified WINS membership. RESULTS: A total of 379 female neurosurgery residency graduates were identified in this 50-yr span. Of these, 70% became ABNS certified, and 2.1% left neurosurgery. Twenty-seven percent of women (n = 103) pursued fellowships, with pediatric neurosurgery (33%) the most common. Regarding practice environment, 26% entered academic medicine (n = 91), with 42 at the rank of assistant professor, 33 at the rank of associate professor, and 16 reaching the rank of full professor. CONCLUSION: Upon completion of training, 27% of women pursue fellowships. The distribution of women in private vs academic practice environments is proportionate to male neurosurgeons; however, the number women in academic leadership positions remains exceedingly low, with disproportionate representation in higher academic ranks. Women in national organized neurosurgery are increasing. Tracking the career paths of women in neurosurgery is a necessary step to identifying current achievements and opportunities for future progress.

A Pilot Study of the Level of Evidence and Collaboration in Published Neurosurgical Research.

OBJECTIVE: Large-scale studies analyzing neurosurgical published research are lacking. This pilot study was designed to assess feasibility of an ongoing annual neurosurgical literature and research analysis of published articles in English-language neurosurgery journals. METHODS: All scientific articles published during 2015 in the print version of 14 English-language neurosurgery journals were reviewed individually. RESULTS: During 2015, 4065 articles were published in 14 neurosurgical journals. Of these, 1116 (27.5%) were nonscientific articles and were excluded from the analysis, and 2949 scientific articles were analyzed. Of these, 2% and 8.5% of publications met criteria for levels of evidence 1 and 2, respectively. One third of published manuscripts (33.2%) were retrospective chart reviews. There were 1742 different centers (mean 1.95 centers per article; range, 1-19) represented in 2949 articles from 67 countries (mean 1.23 countries per article; range, 1-12). Multicenter collaboration was present in 47.5% of published articles, and international collaboration was present in 17.5%. The highest numbers of U.S. author international collaborations were with Canada (70 collaborations), China (33 collaborations) and Italy (25 collaborations). Data for levels of evidence, multicenter collaborations, and international collaborations are presented for each individual journal and subject within neurosurgery. CONCLUSIONS: This pilot analysis provides a descriptive assessment of levels of evidence and collaboration based on journal, general subject matter, and subcategories of subject allowing for comparison. This methodology may be used on an annual basis to establish neurosurgery publication trends and to identify underrepresented areas of research within the specialty.

Tuberous Sclerosis Health Care Utilization Based on the National Inpatient Sample Database: A Review of 5655 Hospitalizations.

INTRODUCTION: Tuberous sclerosis complex (TSC) has an incidence of 1/6000 in the general population. Overall care may be complex and costly. We examine trends in health care utilization and outcomes of patients with TSC over the last decade. METHODS: The National Inpatient Sample (NIS) database for inpatient hospitalizations was searched for admission of patients with TSC. RESULTS: During 2000-2010, the NIS recorded 5655 patients with TSC. Most patients were admitted to teaching hospitals (71.7%). Over time, the percentage of craniotomies performed per year remained stable (P = 0.351). Relevant diagnoses included neuro-oncologic disease (5.4%), hydrocephalus (6.5%), and epilepsy (41.2%). Hydrocephalus significantly increased length of stay and hospital charges. A higher percentage of patients who underwent craniotomy had hydrocephalus (29.8% vs. 5.3%; P < 0.001), neuro-oncologic disease (43.5% vs. 3.4%; P < 0.001), other cranial diseases (4.2% vs. 1.2%; P < 0.001), and epilepsy (61.4% vs. 40.1%; P < 0.001). CONCLUSIONS: Our study identifies aspects of inpatient health care utilization, outcomes, and cost of a large number of patients with TSC. These aspects include related diagnoses and procedures that contribute to longer length of stay, increased hospital cost, and increased in-hospital mortality, which can inform strategies to reduce costs and improve care of patients with TSC.

Cortical screw trajectory for instrumentation and fusion in the setting of osteopathic compression fracture allows for percutaneous kyphoplasty for adjacent level compression fractures.

Spinal fixation in the osteoporotic patient can be challenging due to the poor trabecular bone quality of the vertebral body. Patients with osteoporotic vertebral body compression fractures are at risk for future compression fractures at adjacent levels, especially after cement augmentation. The purpose of this technical report is to describe the utilization of a cortical screw trajectory along with kyphoplasty for a patient with an osteoporotic compression fracture as well as degenerative spinal disease. This trajectory allows for the possibility of percutaneous pedicle access in the event of future compression fractures. Our patient underwent a decompressive laminectomy and kyphoplasty at the level of an osteoporotic compression fracture. The fracture was stabilized with cortical screw instrumentation and fusion at a level above and a level below the fracture. Subsequently the patient developed an adjacent level fracture within the fusion construct. Due to the utilization of a cortical screw trajectory for the initial fusion, the traditional pedicle trajectory was still accessible. As a result, the new fracture was treated with a percutaneous kyphoplasty through a standard pedicle trajectory. In conclusion, the use of a cortical screw trajectory for stabilization of osteoporotic compression fractures provides for a stronger bone screw interface and avoids osteoporotic trabecular vertebral body bone. At the same time this trajectory allows for future percutaneous pedicular access in the event that the patient suffers future compression fractures.

Neurosurgical decision making: personal and professional preferences.

OBJECT: Physicians are often solicited by patients or colleagues for clinical recommendations they would make for themselves if faced by a clinical situation. The act of making a recommendation can alter the clinical course being taken. The authors sought to understand this dynamic across different neurosurgical scenarios by examining how neurosurgeons value the procedures that they offer. METHODS: The authors conducted an online survey using the Congress of Neurological Surgeons listserv in May 2013. Respondents were randomized to answer either as the surgeon or as the patient. Questions encompassed an array of distinct neurosurgical scenarios. Data on practice parameters and experience levels were also collected. RESULTS: Of the 534 survey responses, 279 responded as the "neurosurgeon" and 255 as the "patient." For both vestibular schwannoma and arteriovenous malformation management, more respondents chose resection for their patient but radiosurgery for themselves (p = 0.002 and p = 0.001, respectively). Aneurysm coiling was chosen more often than clipping, but those whose practice was ≥ 30% open cerebrovascular neurosurgery were less likely to choose coiling. Overall, neurosurgeons who focus predominantly on tumors were more aggressive in managing the glioma, vestibular schwannoma, arteriovenous malformation, and trauma. Neurosurgeons more than 10 years out of residency were less likely to recommend surgery for management of spinal pain, aneurysm, arteriovenous malformation, and trauma scenarios. CONCLUSIONS: In the majority of cases, altering the role of the surgeon did not change the decision to pursue treatment. In certain clinical scenarios, however, neurosurgeons chose treatment options for themselves that were different from what they would have chosen for (or recommended to) their patients. For the management of vestibular schwannomas, arteriovenous malformations, intracranial aneurysms, and hypertensive hemorrhages, responses favored less invasive interventions when the surgeon was the patient. These findings are likely a result of cognitive biases, previous training, experience, areas of expertise, and personal values.

Epidural Blood Patch Performed for Severe Intracranial Hypotension Following Lumbar Cerebrospinal Fluid Drainage for Intracranial Aneurysm Surgery. Retrospective Series and Literature Review.

Intracranial hypotension (IH) can occur following lumbar drainage for clipping of an intracranial aneurysm. We observed 3 cases of IH, which were all successfully treated by epidural blood patch (EBP). Herein, the authors report our cases.

Gauging the feasibility of cost-sharing and medical student interest groups to reduce interview costs.

Indirect costs of the interview tour can be prohibitive. The authors sought to assess the desire of interviewees to mitigate these costs through ideas such as sharing hotel rooms and transportation, willingness to stay with local students, and the preferred modality to coordinate this collaboration. A survey link was posted on the Uncle Harvey website and the Facebook profile page of fourth-year medical students from 6 different medical schools shortly after the 2014 match day. There were a total of 156 respondents to the survey. The majority of the respondents were postinterview medical students (65.4%), but preinterview medical students (28.2%) and current residents (6.4%) also responded to the survey. Most respondents were pursuing a field other than neurosurgery (75.0%) and expressed a desire to share a hotel room and/or transportation (77.4%) as well as stay in the dorm room of a medical student at the program in which they are interviewing (70.0%). Students going into neurosurgery were significantly more likely to be interested in sharing hotel/transportation (89.2% neurosurgery vs 72.8% nonneurosurgery; p = 0.040) and in staying in the dorm room of a local student when on interviews (85.0% neurosurgery vs 57.1% nonneurosurgery; p = 0.040) than those going into other specialties. Among postinterview students, communication was preferred to be by private, email identification-only chat room. Given neurosurgery resident candidates' interest in collaborating to reduce interview costs, consideration should be given to creating a system that could allow students to coordinate cost sharing between interviewees. Moreover, interviewees should be connected to local students from neurosurgery interest groups as a resource.

Glioblastoma multiforme: State of the art and future therapeutics.

BACKGROUND: Glioblastoma multiforme (GBM) is the most common and lethal primary malignancy of the central nervous system (CNS). Despite the proven benefit of surgical resection and aggressive treatment with chemo- and radiotherapy, the prognosis remains very poor. Recent advances of our understanding of the biology and pathophysiology of GBM have allowed the development of a wide array of novel therapeutic approaches, which have been developed. These novel approaches include molecularly targeted therapies, immunotherapies, and gene therapy. METHODS: We offer a brief review of the current standard of care, and a survey of novel therapeutic approaches for treatment of GBM. RESULTS: Despite promising results in preclinical trials, many of these therapies have demonstrated limited therapeutic efficacy in human clinical trials. Thus, although survival of patients with GBM continues to slowly improve, treatment of GBM remains extremely challenging. CONCLUSION: Continued research and development of targeted therapies, based on a detailed understanding of molecular pathogenesis can reasonably be expected to yield improved outcomes for patients with GBM.

Comparison of outcomes and utilization of extracranial-intracranial bypass versus intracranial stenting for intracranial stenosis.

BACKGROUND: Extracranial-intracranial (EC-IC) bypass and intracranial stenting (ICS) are both revascularization procedures that have emerged as treatment options for intracranial atherosclerotic disease (ICAD). This study describes and compares recent trends in utilization and outcomes of intracranial revascularization procedures in the United States using a population-based cohort. It also investigates the association of ICS and EC-IC bypass with periprocedural morbidity and mortality, unfavorable discharge status, length of stay (LOS), and total hospital charges. METHODS: The National Inpatient Sample (NIS) was queried for patients with ICAD who underwent EC-IC bypass or ICS during the years 2004-2010. Patient characteristics, demographics, perioperative complications, outcomes, and discharge data were collected. RESULTS: There were 627 patients who underwent ICS and 249 patients who underwent EC-IC bypass. Patients who underwent ICS were significantly older (P < 0.001) with more comorbidities (P = 0.027) than those who underwent EC-IC bypass. Patients who underwent EC-IC bypass experienced higher rates of postprocedure stroke (P = 0.014), but those who underwent ICS experienced higher rates of death (P = 0.006). Among asymptomatic patients, the rates of postprocedure stroke (P = 0.341) and death (P = 0.887) were similar between patients who underwent ICS and those who underwent EC-IC bypass. Among symptomatic patients, however, there was a higher rate of postprocedure stroke in patients who underwent EC-IC bypass (P < 0.001) and a higher rate of death among patients who underwent ICS (P = 0.015). CONCLUSION: The ideal management of patients with ICAD cannot yet be defined. Although much data from randomized and prospective trials on revascularization have been collected, many questions remain unanswered. There still remain cohorts of patients, specifically patients who have failed aggressive medical management, where not enough evidence is available to dictate decision-making. In order to further elucidate the safety and efficacy of these intracranial revascularization procedures, further clinical trials are needed.

National trends in utilization and outcomes of angioplasty and stenting for revascularization in intracranial stenosis.

INTRODUCTION: Angioplasty and intracranial stenting (ICS) are both endovascular revascularization procedures that have emerged as treatment options for intracranial atherosclerotic disease (ICAD). Some believe angioplasty alone is better, while others believe stenting is better. This study examines recent trends in utilization and outcomes of angioplasty alone and ICS in the United States using a population-based cohort. METHODS: The National Inpatient Sample (NIS) database was queried for patients with ICAD who underwent angioplasty or ICS from 2005 to 2010. RESULTS: There were 1115 patients (angioplasty: n=495, ICS: n=620) with ICAD who underwent endovascular revascularization. Over time, the number of endovascular revascularization procedures increased. The percentage of symptomatic patients (p=0.015) as well as in the number of comorbidities of patients treated (p<0.001) also increased. Combined post-procedure stroke and death rates were 16% and 28.9% for angioplasty and ICS, respectively (p<0.001). A larger percentage of angioplasty patients presented symptomatically compared to those who underwent ICS (p<0.001). CONCLUSION: Angioplasty appears to be associated with higher rates of peri-procedural complications; however, that may represent patient selection bias. Further studies are needed to identify patients who would benefit from revascularization and to clarify the roles of angioplasty and ICS.

A comparative review of the hemodynamics and pathogenesis of cerebral and abdominal aortic aneurysms: lessons to learn from each other.

OBJECTIVE: Cerebral aneurysms (CAs) and abdominal aortic aneurysms (AAAs) are degenerative vascular pathologies that manifest as abnormal dilations of the arterial wall. They arise with different morphologies in different types of blood vessels under different hemodynamic conditions. Although treated as different pathologies, we examine common pathways in their hemodynamic pathogenesis in order to elucidate mechanisms of formation. MATERIALS AND METHODS: A systematic review of the literature was performed. Current concepts on pathogenesis and hemodynamics were collected and compared. RESULTS: CAs arise as saccular dilations on the cerebral arteries of the circle of Willis under high blood flow, high wall shear stress (WSS), and high wall shear stress gradient (WSSG) conditions. AAAs arise as fusiform dilations on the infrarenal aorta under low blood flow, low, oscillating WSS, and high WSSG conditions. While at opposite ends of the WSS spectrum, they share high WSSG, a critical factor in arterial remodeling. This alone may not be enough to initiate aneurysm formation, but may ignite a cascade of downstream events that leads to aneurysm development. Despite differences in morphology and the structure, CAs and AAAs share many histopathological and biomechanical characteristics. Endothelial cell damage, loss of elastin, and smooth muscle cell loss are universal findings in CAs and AAAs. Increased matrix metalloproteinases and other proteinases, reactive oxygen species, and inflammation also contribute to the pathogenesis of both aneurysms. CONCLUSION: Our review revealed similar pathways in seemingly different pathologies. We also highlight the need for cross-disciplinary studies to aid in finding similarities between pathologies.