Atherogenesis and Lymphstasis...Connecting the Dots.

"The Role of Lymphstasis in Atherogenesis" appeared in the Annals of Thoracic Surgery in the March 1981 issue which examined the significance of lymphatic involvement in arteriosclerosis. Presently, the underlying premise of the original paper is reviewed with its relationship to recent information regarding reverse cholesterol transport.Since then, an ncreasing number of articles have been published identifying the proteins and peptides that play a critical role in lymphatic clearance of arterial wall cholesterol. This process, its relationship to the 1981 article, and a concept of arteriosclerosis that explains the scientific merit of the beneficial effects of lifestyle is presented.

Brain tumors enhance plasmatic coagulation: the role of hemeoxygenase-1.

BACKGROUND: Patients with brain tumors suffer significant thrombotic morbidity and mortality. In addition to increased thrombin generation via tumor release of tissue factor-bearing microparticles and hyperfibrinogenemia, brain tumors and surrounding normal brain likely generate endogenous carbon monoxide (CO) via the hemeoxygenase-1 (HO-1) system. CO has been shown to enhance plasmatic coagulation via formation of carboxyhemefibrinogen (COHF). Thus, our goals in this study were to determine whether patients with brain tumors had increased HO-1 upregulation/CO production, plasmatic hypercoagulability, and formation of COHF. METHODS: Patients with brain tumors (N = 20) undergoing craniotomy had blood collected for determination of carboxyhemoglobin as a marker of HO-1 activity, plasmatic hypercoagulability (defined as clot strength > 95% confidence interval value of normal subject plasma), and COHF formation (determined with a thrombelastograph-based assay). Plasma obtained from commercially available normal subjects (N = 30) was used for comparison with brain tumor patient samples. RESULTS: Brain tumor patients had carboxyhemoglobin concentrations of 1.5% ± 0.5% (mean ± SD), indicative of HO-1 upregulation. Compared with normal subject plasma, brain tumor patient plasma had significantly (P < 0.0001) greater clot formation velocity (5.2 ± 1.5 vs 9.5 ± 2.3 dynes/cm/s, respectively) and significantly (P = 0.00016) stronger final clot strength (166 ± 28 vs 230 ± 78 dynes/cm, respectively). Ten of the brain tumor patients had plasma clot strength that exceeded the 95% confidence interval value observed in normal subjects, and 12 of the brain tumor patients had COHF formation. Five of the brain tumor patients in the hypercoagulable subgroup had COHF formation. Last, 5 of the hypercoagulable patients had primary brain tumors, whereas the other 5 patients had metastatic tumors or an inflammatory mass lesion. CONCLUSIONS: A subset of patients with brain tumors has increased endogenous CO production, plasmatic hypercoagulability, and COHF formation. Future investigation of the role played by HO-1 derived CO in the pathogenesis of brain tumor-associated thrombophilia is warranted.

Objective assessment of postural ergonomics in neurosurgery: integrating wearable technology in the operating room.

OBJECTIVE: Physical stress associated with the static posture of neurosurgeons over prolonged periods can result in fatigue and musculoskeletal disorders. Objective assessment of surgical ergonomics may contribute to postural awareness and prevent further complications. This pilot study examined the feasibility of using wearable technology as a biofeedback tool to address this gap. METHODS: Ten neurosurgeons, including 5 attendings (all faculty) and 5 trainees (1 fellow, 4 residents), were recruited and equipped with two wearable sensors attached to the back of their head and their upper back. The sensors collected the average time spent in extended (≤ -10°), neutral (> -10° and < 10°), and flexed (≥ 10°) static postures (undetected activity for more than 10 seconds) during spine and cranial procedures. Feasibility outcomes aimed for more than 70% of accurate data collection. Exploratory outcomes included the comparison of postural variability within and between participants adjusted to their demographics excluding nonrelated surgical activities, and postoperative self-assessment surveys. RESULTS: Sixteen (80%) of 20 possible recordings were successfully collected and analyzed from 11 procedures (8 spine, 3 cranial). Surgeons maintained a static posture during 52.7% of the active surgical time (mean 1.58 hrs). During spine procedures, all surgeons used an exoscope while standing, leading to a significantly longer time spent in a neutral static posture (p < 0.001, partial η2 = 0.14): attendings remained longer in a neutral static posture (36.4% ± 15.3%) than in the extended (9% ± 6.3%) and flexed (5.7% ± 3.4%) static postures; trainees also remained longer in a neutral static posture (30.2% ± 13.8%) than in the extended (11.1% ± 6.3%) and flexed (11.9% ± 6.6%) static postures. During cranial procedures, surgeons intermittently transitioned between standing/exoscope use and sitting/microscope use, with trainees spending a shorter time in a neutral static posture (16.3% vs 48.5%, p < 0.001) and a longer time in a flexed static posture (18.5% vs 2.7%, p < 0.001) compared with attendings. Additionally, longer cranial procedures correlated with surgeons spending a longer time (r = 0.94) in any static posture (extended, flexed, and neutral), with taller surgeons exhibiting longer periods in flexed and extended static postures (r = 0.86). Postoperative self-assessment revealed that attendings perceived spine procedures as more difficult than trainees (p = 0.029), while trainees found cranial procedures to be of greater difficulty than spine procedures (p = 0.012). Attendings felt more stressed (p = 0.048), less calmed (p = 0.024), less relaxed (p = 0.048), and experienced greater stiffness in their upper body (p = 0.048) and more shoulder pain (p = 0.024) during cranial versus spine procedures. CONCLUSIONS: Wearable technology is feasible to assess postural ergonomics and provide objective biofeedback to neurosurgeons during spine and cranial procedures. This study showed reproducibility for future comparative protocols focused on correcting posture and surgical ergonomic education.

Cerebrospinal Fluid Drainage in Patients with Acute Spinal Cord Injury: A Multi-Center Randomized Controlled Trial.

OBJECTIVE: The secondary phase of spinal cord injury (SCI) is characterized by ischemic injury. Spinal cord perfusion pressure (SCPP), calculated as the difference between mean arterial pressure (MAP) and intrathecal pressure (ITP), has arisen as a therapeutic target for improving outcomes. Cerebrospinal fluid drainage (CSFD) may reduce ITP and thereby increase SCPP. Randomized controlled trial to evaluate the safety and feasibility of CSFD to improve SCPP and outcomes after acute SCI. METHODS: Inclusion criteria included acute cervical SCI within 24 hours of presentation. All patients received lumbar drain placement and appropriate decompressive surgery. Patients randomized to the control group received MAP elevation only. Patients in the experimental group received MAP elevation and CSFD to achieve ITP <10 mmHg for 5 days. ITP and MAP were recorded hourly. Adverse events were documented and patients underwent functional assessments at enrollment, 72 hours, 90 days, and 180 days post-injury. RESULTS: Eleven patients were enrolled; 4 were randomized to receive CSFD. CSFD patients had a mean ITP of 5.3 ± 2.5 mmHg versus. 15 ± 3.0 mmHg in the control group. SCPP improved significantly, from 77 ± 4.5 mmHg in the control group to 101 ± 6.3 mmHg in the CSFD group (P < 0.01). Total motor scores improved by 15 ± 8.4 and 57 ± 24 points in the control and CSFD groups, respectively, over 180 days. No adverse events were attributable to CSFD. CONCLUSIONS: CSFD is a safe, effective mechanism for reducing ITP and improving SCPP in the acute period post-SCI. The favorable safety profile and preliminary efficacy should help drive recruitment in future studies.

Combined Transcranial and Endoscopic Endonasal Approach for Resection of a Complex Sinonasal Squamous Cell Carcinoma: Two-Dimensional Operative Video.

Sinonasal squamous cell carcinoma (SCC) is a rare head-and-neck neoplasm that has a propensity to locally invade vital structures. Currently, the combination of surgical resection and radiation remains the optimal treatment. 1 However, the extent of disease burden and involvement of surrounding anatomy may make these inoperable. Here, we demonstrate the successful application of multidisciplinary approach for surgical resection of a large, complex SCC lesion centered at the superior nasal cavity with extension into the eye orbits and brain. A two-step approach was performed; transcribiform, endoscopic piecemeal resection with reconstruction of the skull base, followed by a bifrontal craniotomy. Reconstruction was achieved using an inlay of DuraMatrix allograft (Stryker Inc., Kalamzoo, Michigan, United States) followed by an inlay of AlloDerm (Allergan Inc., Irvine, California, United States), anchored anteriorly and posteriorly with wide wings placed over the respective orbital roofs. Major steps include (1) a summary of the patient presentation and preoperative imaging, (2) resection of the tumor endonasally, (3) resection of the tumor intracranially from a bifrontal craniotomy, and (4) a review of the postoperative imaging. The patient tolerated the procedure ( Fig. 1 ) well, returned to his baseline with no new neurologic deficits, and was placed on 6-week antibiotics regimen for osteomyelitis discovered during the operation. Approximately, 2 months after discharge, the patient unfortunately returned with altered mental status, was found to have sepsis, and expired shortly thereafter. This operative video illustrates the technical steps and capabilities of surgical treatment, achieving near-complete gross total resection of a complex SCC lesion using a multidisciplinary approach. The link to the video can be found at: https://youtu.be/8ffckKIuBzM .

Multiple Extraaxial Cavernous Hemangiomas: Rare Entity.

BACKGROUND: Cavernous hemangiomas arising in the extraaxial space are rarely encountered, often mimicking other more common pathologies. Furthermore, multiple coexisting lesions and posterior fossa involvement are scarcely reported. Herein, we present the case of a patient with concurrent frontal bone and posterior fossa extraaxial cavernous hemangiomas. We also review the challenges associated with the diagnosis and management of these entities. CASE DESCRIPTION: An otherwise healthy 41-year-old gentleman presented with a 7-month history of a progressive right forehead mass. Imaging demonstrated a right frontal bone mass and an incidentally noted transverse sinus-based mass. The patient opted for surgical resection of both lesions. A right frontal craniotomy was performed to remove the bony lesion, followed by a suboccipital approach for the dural-based mass. There were no significant complications intraoperatively, and gross total resection was achieved for both lesions. Final pathology for each was consistent with cavernous hemangioma. CONCLUSIONS: Extraaxial cavernous hemangiomas are uncommon clinical entities that are challenging to distinguish from other diseases. If intraoperative complications can be avoided, treatment with surgical resection often offers excellent patient outcomes.

Suprasellar pleomorphic xanthoastrocytoma: A case report.

BACKGROUND: Pleomorphic xanthoastrocytoma (PXA) is a rare form of astrocytic neoplasm most commonly found in children and young adults. This neoplasm, which is classified as a Grade II tumor by the World Health Organization classification of tumors of the central nervous system, carries a relatively favorable outcome. It is usually found supratentorially in cortical regions of the cerebral hemispheres, and as such, presenting symptoms are similar to other supratentorial cortical neoplasms; with seizures being a common initial symptom. Due to the rarity of this type of neoplasm, PXA arising elsewhere in the brain is often not included in the initial differential diagnosis. CASE DESCRIPTION: This report presents an extremely rare patient with PXA arising in the suprasellar region who presented with progressive peripheral vision loss. Magnetic resonance imaging of the brain demonstrated a heterogeneous suprasellar mass with cystic and enhancing components initially; the most likely differential diagnosis was craniopharyngioma. The patient underwent endoscopic endonasal resection of the tumor. Microscopically, the tumor was consistent with a glial neoplasm with variable morphology. Based on these findings along with further immunohistochemical workup, the patient was diagnosed with a PXA arising in the suprasellar region. At the 1-year follow-up, the patient remained free of recurrence. Although rare PXA originating in other uncommon locations, such as the spinal cord, cerebellum, the ventricular system, and the pineal region have been previously described. CONCLUSION: Although rare, PXA should be included in the differential diagnosis for solid-cystic tumors arising in the suprasellar region in young adults.

Neurotrauma From Border Wall Jumping: 6 Years at the Mexican-American Border Wall.

BACKGROUND: The border between the United States (US) and Mexico is an international boundary spanning 3000 km, where unauthorized crossings occur regularly. We examine patterns of neurotrauma, health care utilization, and financial costs at our level 1 trauma center incurred by patients from wall-jumping into the US. OBJECTIVE: To determine the clinical and socioeconomic consequences from neurotrauma as a result of jumping over the US-Mexico border wall. METHODS: Medical records of patients at (Banner University of Arizona Medical Center - Tucson) were retrospectively reviewed from January 2012 through December 2017. Demographics, clinical status, radiographic findings, treatment, length of stay, and financial data were analyzed for all patients suffering neurotrauma during that time. RESULTS: Over 6 yr, 64 patients sustained cranial or spinal injuries directly from jumping or falling onto US soil from the border wall. Fifty (78%) suffered spinal injuries, 15 (23%) experienced cranial injury, and 1 patient had both. Total medical charges were available in 36 patients and summed $3.6 M, of which 22% was reimbursed, an amount significantly lower than expected from more conventional trauma. Neurotrauma steadily declined over the 6-yr observation period, dropping in 2017 to 6% of rates observed in 2012. CONCLUSION: In the Southern US, neurotrauma from unauthorized border crossings occurs commonly as a result of wall-jumping. These injuries represent a clinical and costly extreme of border-related trauma, and future efforts from both sides of the border wall are needed to decrease the detrimental impacts felt both by immigrants and surrounding health care systems.

A novel proposed grading system for cerebellar arteriovenous malformations.

OBJECTIVE: The objective of this study was to evaluate the existing Spetzler-Martin (SM), Spetzler-Ponce (SP), and Lawton-Young (LY) grading systems for cerebellar arteriovenous malformations (AVMs) and to propose a new grading system to estimate the risks associated with these lesions. METHODS: Data for patients with cerebellar AVMs treated microsurgically in two tertiary medical centers were retrospectively reviewed. Data from patients at institution 1 were collected from September 1999 to February 2013, and at institution 2 from October 2008 to October 2015. Patient outcomes were classified as favorable (modified Rankin Scale [mRS] score 0-2) or poor (mRS score 3-6) at the time of discharge. Using chi-square and logistic regression analysis, variables associated with poor outcomes were assigned risk points to design the proposed grading system. The proposed system included neurological status prior to treatment (poor, +2 points), emergency surgery (+1 point), age > 60 years (+1 point), and deep venous drainage (deep, +1 point). Risk point totals of 0-1 comprised grade 1, 2-3 grade 2, and 4-5 grade 3. RESULTS: A total of 125 cerebellar AVMs of 1328 brain AVMs were reviewed in 125 patients, 120 of which were treated microsurgically and included in the study. With our proposed grading system, we found poor outcomes differed significantly between each grade (p < 0.001), while with the SM, SP, and LY grading systems they did not (p = 0.22, p = 0.25, and p = 1, respectively). Logistic regression revealed grade 2 had 3.3 times the risk of experiencing a poor outcome (p = 0.008), while grade 3 had 9.9 times the risk (p < 0.001). The proposed grading system demonstrated a superior level of predictive accuracy (area under the receiver operating characteristic curve [AUROC] of 0.72) compared with the SM, SP, and LY grading systems (AUROC of 0.61, 0.57, and 0.51, respectively). CONCLUSIONS: The authors propose a novel grading system for cerebellar AVMs based on emergency surgery, venous drainage, preoperative neurological status, and age that provides a superior prognostication power than the formerly proposed SM, SP, and LY grading systems. This grading system is clinically predictive of patient outcomes and can be used to better guide vascular neurosurgeons in clinical decision-making.

Intraoperative brain tumor resection with indocyanine green using augmented microscopy.

Treatment outcomes for brain cancer have seen dismal improvements over the last two decades as evident in available statistical data. Efforts to address this challenge include development of near-infrared contrast agents for improvements in diagnostic and therapeutic modalities. This creates a need for imaging technologies that can support the intraoperative use of such agents. Here, we report implementation of a recently introduced augmented microscope in combination with indocyanine green (ICG), a near-infrared contrast agent, for surgical image guidance of a glioma resection in a rat model. Luc-C6 cells were implanted in rats in the left-frontal lobe and grown for 22 days. Surgical resection was performed by a neurosurgeon using the augmented microscope with ICG contrast. ICG accumulated in the tumor tissue due to enhanced permeation and retention from the compromised blood-brain barrier. Videos and images were acquired to evaluate image quality and resection margins. The augmented microscope highlighted tumor tissue regions via visualization of ICG fluorescence and was capable of guiding the rat glioma resection.

Hemodynamics Associated With Intracerebral Arteriovenous Malformations: The Effects of Treatment Modalities.

The understanding of the physiology of cerebral arteriovenous malformations (AVMs) continues to expand. Knowledge of the hemodynamics of blood flow associated with AVMs is also progressing as imaging and treatment modalities advance. The authors present a comprehensive literature review that reveals the physical hemodynamics of AVMs, and the effect that various treatment modalities have on AVM hemodynamics and the surrounding cortex and vasculature. The authors discuss feeding arteries, flow through the nidus, venous outflow, and the relative effects of radiosurgical monotherapy, endovascular embolization alone, and combined microsurgical treatments. The hemodynamics associated with intracranial AVMs is complex and likely changes over time with changes in the physical morphology and angioarchitecture of the lesions. Hemodynamic change may be even more of a factor as it pertains to the vast array of single and multimodal treatment options available. An understanding of AVM hemodynamics associated with differing treatment modalities can affect treatment strategies and should be considered for optimal clinical outcomes.

The Unique Features and Outcomes of Microsurgically Resected Cerebellar Arteriovenous Malformations.

BACKGROUND: Cerebellar arteriovenous malformations (CAVMs) are challenging to treat given their close proximity to the brain stem, greater propensity for rupture, and greater rates of morbidity and mortality than other brain arteriovenous malformations. The present investigation sought to describe and characterize the features of these rare and unique lesions. METHODS: A retrospective review of CAVM cases treated at 2 tertiary medical centers was performed. Patients surgically treated at institution 1 from September 1999 to February 2013 and institution 2 from October 2008 to October 2015 were included. RESULTS: A total of 120 patients had been treated. Of the 120 patients, 85 (70.8%) had initially presented with hemorrhage, 45 (37.5%) of whom experienced hemorrhage requiring emergent surgery. A favorable neurological outcome was observed in 76 patients (63.3%; modified Rankin Scale score <3). The perioperative mortality was 2.5% (n = 3). The long-term mortality rate was 7.5% (n = 9). The mean follow-up time was 1.82 years. On average, the patients with large CAVMs (≥3 cm; P ≤ 0.001), who had received embolization before surgery (P = 0.04), did not have an associated aneurysm (P ≤ 0.001), or had a residual CAVM after surgery (P = 0.008) were significantly younger. Female patients had fewer CAVMs with deep venous drainage (54.3% vs. 72.3%; P = 0.049), experienced decreased mortality (1.4% vs. 16.7%; P = 0.003), and were less likely to have worse neurological status after treatment (P = 0.003). CONCLUSIONS: CAVMs are rare lesions that exhibit unique disease characteristics. Although most patients will experience a favorable outcome, CAVMs frequently present with hemorrhage, result in high rates of morbidity and mortality, and characteristically differ depending on patient age and gender.

Accuracy of ventriculostomy catheter placement using a head- and hand-tracked high-resolution virtual reality simulator with haptic feedback.

OBJECT: The purpose of this study was to evaluate the accuracy of ventriculostomy catheter placement on a head- and hand-tracked high-resolution and high-performance virtual reality and haptic technology workstation. METHODS: Seventy-eight fellows and residents performed simulated ventriculostomy catheter placement on an ImmersiveTouch system. The virtual catheter was placed into a virtual patient's head derived from a computed tomography data set. Participants were allowed one attempt each. The distance from the tip of the catheter to the Monro foramen was measured. RESULTS: The mean distance (+/- standard deviation) from the final position of the catheter tip to the Monro foramen was 16.09 mm (+/- 7.85 mm). CONCLUSIONS: The accuracy of virtual ventriculostomy catheter placement achieved by participants using the simulator is comparable to the accuracy reported in a recent retrospective evaluation of free-hand ventriculostomy placements in which the mean distance from the catheter tip to the Monro foramen was 16 mm (+/- 9.6 mm).

Socioeconomic and regional differences in the treatment of cervical spondylotic myelopathy.

BACKGROUND: Cervical spondylotic myelopathy (CSM) is the leading cause of spinal cord dysfunction in the world. Surgical treatment is both medically and economically advantageous, and can be achieved through multiple approaches, with or without fusion. We used the Nationwide Inpatient Sample (NIS) database to better elucidate regional and socioeconomic variances in the treatment of CSM. METHODS: The NIS database was queried for elective admissions with a primary diagnosis of CSM (ICD-9 721.1). This was evaluated for patients who also carried a diagnosis of anterior (ICD-9 81.02) or posterior cervical fusion (ICD-9 81.03), posterior cervical laminectomy (ICD 03.09), or a combination. We then investigated variances including regional trends and disparities according to hospital and insurance types. RESULTS: During 2002-2012, 50605 patients were electively admitted with a diagnosis of CSM. Anterior fusions were more common in Midwestern states and in nonteaching hospitals. Fusion procedures were used more frequently than other treatments in private hospitals and with private insurance. Median hospital charges were also expectedly higher for fusion procedures and combined surgical approaches. Combined approaches were found to be significantly greater in patients with concurrent diagnoses of ossification of the posterior longitudinal ligament (OPLL) and CSM. Ultimately, there has been an increased utilization of fusion procedures versus nonfusion treatments, over the past decade, for patients with cervical myelopathy. CONCLUSIONS: Fusion surgery is being increasingly used for the treatment of CSM. Expensive procedures are being performed more frequently in both private hospitals and for those with private insurance, whereas the most economical procedure, posterior cervical laminectomy, was underutilized.

Intracranial Hemorrhage in Patients with Durable Mechanical Circulatory Support Devices: Institutional Review and Proposed Treatment Algorithm.

BACKGROUND: Spontaneous intracranial hemorrhage (ICH) is frequently managed in neurosurgery. Patients with durable mechanical circulatory support devices, including total artificial heart (TAH) and left ventricular assist device (LVAD), are often encountered in the setting of ICH. Although durable mechanical circulatory support devices have improved survival and quality of life for patients with advanced heart failure, ICH is one of the most feared complications following LVAD and TAH implantation. Owing to anticoagulation and clinically relevant acquired coagulopathies, ICH should be treated promptly by neurosurgeons and cardiac critical care providers. We provide an analysis of ICH in patients with mechanical circulatory support and propose a treatment algorithm. METHODS: We retrospectively reviewed medical records from 2013-2016 for patients with a durable mechanical circulatory device at Banner-University of Arizona Medical Center Tucson. All patients with suspected ICH underwent computed tomography scan of the brain. Anticoagulation was managed by the cardiothoracic surgeon. RESULTS: In 58 patients, an LVAD (n = 49), TAH (n = 10), or both (n = 1) were implanted. Both acquired von Willebrand disease and spontaneous ICH were diagnosed in 5 patients (8.6%) who underwent LVAD implantation. Seven neurosurgical procedures were performed in 2 patients. The overall mortality rate was 60%. Two patients had little or no deficits after treatment with modified Rankin Scale score of 1 and 2, respectively. CONCLUSIONS: We propose a novel treatment algorithm to manage patients with a LVAD or TAH and ICH, implemented in a multidisciplinary manner to best avoid neurologic and cardiovascular complications.

Complex Skull Base Reconstructions in Kadish D Esthesioneuroblastoma: Case Report.

Introduction Advanced Kadish stage esthesioneuroblastoma requires more extensive resections and aggressive adjuvant therapy to obtain adequate disease-free control, which can lead to higher complication rates. We describe the case of a patient with Kadish D esthesioneuroblastoma who underwent multiple surgeries for infectious, neurologic, and wound complications, highlighting potential preventative and salvage techniques. Case Presentation A 61-year-old man who presented with a large left-sided esthesioneuroblastoma, extending into the orbit, frontal lobe, and parapharyngeal nodes. He underwent margin-free endoscopic-assisted craniofacial resection with adjuvant craniofacial and cervical radiotherapy and concomitant chemotherapy. He then returned with breakdown of his skull base reconstruction and subsequent frontal infections and ultimately received 10 surgical procedures with surgeries for infection-related issues including craniectomy and abscess evacuation. He also had surgeries for skull base reconstruction and CSF leak, repaired with vascularized and free autologous grafts and flaps, synthetic tissues, and CSF diversion. Discussion Extensive, high Kadish stage tumors necessitate radical surgical resection, radiation, and chemotherapy, which can lead to complications. Ultimately, there are several options available to surgeons, and although precautions should be taken whenever possible, risk of wound breakdown, leak, or infection should not preclude radical surgical resection and aggressive adjuvant therapies in the treatment of esthesioneuroblastoma.

Effective Surgical Management of Competitive Venous Outflow Restriction After Radiosurgery for Cerebral AVMs: Report of 2 Cases.

BACKGROUND: Intracranial arteriovenous malformations (AVMs) are complex pathologies. For patients who do not present with hemorrhage, treatment strategies are often predicated on reducing the risk of hemorrhage and minimizing morbidity. Outcomes vary according to the efficacy of treatment selected. Radiosurgical treatment of certain AVMs can result in incomplete obliteration and may also have only a minimal effect on the presenting nonhemorrhagic symptoms. CASE DESCRIPTIONS: We present 2 cases of patients with AVMs who were initially treated with radiosurgery. Both patients' primary clinical symptoms were headaches, which persisted after radiosurgical treatment but abated after subsequent microsurgical resection with or without endovascular embolization. CONCLUSION: Venous outflow obstruction is likely a sizable contributive factor in occipital AVMs among patients who present with headaches and symptoms of intracranial hypertension. Because these high-flow lesions may be suboptimally responsive to stereotactic radiosurgery, microsurgical resection, with or without adjunctive endovascular embolization, should be considered as an initial and definitive treatment strategy. Optimal outcomes may be achieved in patients with a visual deficit that is anatomically correlated to their AVMs.

Second generation haptic ventriculostomy simulator using the ImmersiveTouch system.

Ventriculostomy is a neurosurgical procedure that consists of the insertion of a catheter into the ventricles of the brain for relieving the intracranial pressure. A distinct "popping" sensation is felt as the catheter enters the ventricles. Early ventriculostomy simulators provided some basic audio/visual feedback to simulate the procedure, displaying a 3D virtual model of a human head. Without any tactile feedback, the usefulness of such simulators was very limited. The first generation haptic ventriculostomy simulators incorporated a haptic device to generate a virtual resistance and "give" upon ventricular entry. While this created considerable excitement as a novelty device for cannulating ventricles, its usefulness for teaching and measuring neurosurgical expertise was still very limited. Poor collocation between the haptic device stylus held by the surgeon and the visual representation of the virtual catheter, as well as the lack of a correct viewer-centered perspective, created enormous confusion for the neurosurgeons who diverted their attention from the actual ventriculostomy procedure to overcoming the limitations of the simulator. We present a second generation haptic ventriculostomy simulator succeeding over the major first generation limitations by introducing a head and hand tracking system as well as a high-resolution high-visual-acuity stereoscopic display to enhance the perception and realism of the virtual ventriculostomy.

On resident duty hour restrictions and neurosurgical training: review of the literature.

Within neurosurgery, the national mandate of the 2003 duty hour restrictions (DHR) by the Accreditation Council for Graduate Medical Education (ACGME) has been controversial. Ensuring the proper education and psychological well-being of residents while fulfilling the primary purpose of patient care has generated much debate. Most medical disciplines have developed strategies that address service needs while meeting educational goals. Additionally, there are numerous studies from those disciplines; however, they are not specifically relevant to the needs of a neurosurgical residency. The recent implementation of the 2011 DHR specifically aimed at limiting interns to 16-hour duty shifts has proven controversial and challenging across the nation for neurosurgical residencies--again bringing education and service needs into conflict. In this report the current literature on DHR is reviewed, with special attention paid to neurosurgical residencies, discussing resident fatigue, technical training, and patient safety. Where appropriate, other specialty studies have been included. The authors believe that a one-size-fits-all approach to residency training mandated by the ACGME is not appropriate for the training of neurosurgical residents. In the authors' opinion, an arbitrary timeline designed to limit resident fatigue limits patient care and technical training, and has not improved patient safety.

Measuring Quality of Neurosurgical Care: Readmission Is Affected by Patient Factors.

OBJECTIVE: The Hospital Readmission Reduction Program section of the Patient Protection and Affordable Care Act uses readmission rates as a proxy for measuring quality of care. Multiple studies have demonstrated that readmission rates are highly imprecise proxies for quality of care because readmission rates contain large amounts of statistical noise and are dependent on disease type, insurance type, severity, population, and a multitude of other factors. The current study was conducted to investigate characteristics associated with readmission and the quality of neurosurgical care. METHODS: Admissions data were gleaned from the University Health System Consortium database for neurosurgical patient (both cranial and spine) readmissions to assess patient-related factors relating to readmission from January 2011 to December 2014. RESULTS: Among 257,212 admissions for neurosurgical disease analyzed, patients with Medicaid and private payers as a primary insurance source had increased rates of readmission (odds ratio for readmission of 1.38 and 1.17, respectively) compared with patients with Medicare or other primary insurers. Patients with greater severity of disease and emergent or urgent admission also had statistically significant rates of readmission. CONCLUSIONS: The findings suggest that readmission is affected by patient factors that are beyond the control of treating physicians. These findings also suggest that readmission rates may not be a good proxy for measurement of quality of care in neurosurgical patients.