Risk Factors for Dropping Out of Neurosurgical Residency Programs-A Survey Study.

BACKGROUND: Resident education has to adapt to a changing health care environment. Although aspects such as working hours and attrition rates have been studied in detail, data about the residents' perspective, especially in European countries, are underrepresented in the scientific literature. The aim of this study was to assess and report aspects of neurosurgical education in German-speaking countries and to identify risk factors for quitting or changing the neurosurgical residency program. METHODS: We conducted a nonanonymous online survey among neurosurgical residents in Germany, Austria, and Switzerland. Log-binomial regression models were calculated to further assess risk factors. RESULTS: Of 201 residents who responded to the survey, 37.3% (n = 75) dropped out of neurosurgical training programs, including 20 residents (10%) who ultimately quit neurosurgery and changed to another specialty. Only female gender (relative risk, 2.97; 95% confidence interval, 1.3-6.78) and starting residency in a city one studied or grew up in (2.38; 1.01-5.62) were significant risk factors. Residents who had close supervision at work (0.39; 0.17-0.89), who observed the residency program for >3 days before applying (0.54; 0.31-0.95), who had well-defined guidelines within the program (0.57; 0.35-0.92), and who were working in a university hospital (0.41; 0.26-0.64) were significantly less likely to quit or change their program. CONCLUSIONS: The high attrition rate, especially among female residents, in Germany, Austria, and Switzerland should encourage program directors to specifically address the issues reported by this survey during interviews and to further improve their residency program accordingly.

Surgical treatment of spinal metastases from renal cell carcinoma-effects of preoperative embolization on intraoperative blood loss.

The objective of this paper is analyzing the effects of preoperative embolization on intraoperative blood loss in spinal surgery for renal cell carcinoma (RCC) metastasis and identifying factors contributing to an increased blood loss in the surgical procedure. A retrospective analysis was performed in patients who were treated in for spinal metastasis from RCC between 2011 and 2016. Factors analyzed were reduction of tumor blush, timing of embolization, selective vs. superselective approach, surgical factors, and tumor volume and localization. Parameters were statistically correlated with intraoperative blood loss (hemoglobin (Hg) decrease, blood loss in milliliters, number of transfused blood bags). Twenty-five patients with 34 surgical interventions were included. Seventeen cases were treated superselectively and 11 treated selectively. Mean perioperative blood loss was 2248 ± 1833 ml. Higher blood loss was detected for vertebra replacement compared to percutaneous procedures (Hg decrease 4.22 vs. 2.62, p < 0.05). Blood loss increased with increasing tumor volumes (0-50 ccm/50-100 ccm/> 100 ccm) for Hg loss (3.29/3.64/4.24 mg/dl, NS), blood loss in milliliters (1291/2620/4971 ml, p < 0.001), and number of transfusions (1.2/3.4/7.0, p < 0.001). Stratifying by the grade of embolization, no significant differences were found between the groups (> 90%/90-75%/75-50%) for Hg loss, blood loss, or number of transfusions. Endovascular embolization for RCC metastasis of the spine is a safe procedure; however, in this cohort, patients undergoing embolization did not show a reduced blood loss in comparison to the non-embolized cohort. Additional factors contributing to an increased blood loss were tumor size and mode of surgery.

Angioarchitectural Risk Factors for Hemorrhage and Clinical Long-Term Outcome in Pediatric Patients with Cerebral Arteriovenous Malformations.

BACKGROUND: Intracranial arteriovenous malformation (AVM) in children is a rare diagnosis. Little is known about factors determining AVM rupture and appropriate treatment strategies to prevent hemorrhage and associated disability. Available data suggest that children are subject to an increased risk for AVM rupture compared with adults. METHODS: In 46 pediatric patients with AVM, demographic factors, clinical presentation, angioarchitectural features, and treatment regimens as well as clinical and radiologic outcomes were retrospectively analyzed. First-line treatment option was microsurgical resection of the disease, with or without preoperative embolization. RESULTS: Twenty-four boys (52.2%) and 22 girls (47.8%) with a mean age on admission of 12.4 years (4-18 years) were included. Mean follow-up was 4 years (median, 1.5; range, 0.1-16.4). Thirty-one children presented with intracerebral hemorrhage (67.4%). Small AVMs (<3 cm) ruptured in 83.3% (n = 25) and were shown to be more prone to hemorrhage than larger ones (P < 0.01). Small AVM size (P < 0.01; odds ratio [OR], 0.12; 95% confidence interval [CI] 0.02-0.59) and exclusive deep venous drainage (P < 0.01; OR, 29.74; 95% CI, 2.45-4445.34) were independent risk factors for hemorrhage in the presented cohort. Good long-term outcome was associated with a high score on the Glasgow Coma Scale on admittance (P < 0.05; OR, 0.148; 95% CI, 0.03-0.73). CONCLUSIONS: Two-thirds of children with AVM are admitted with intracerebral hemorrhage. Microsurgical resection was successful as confirmed by radiologic studies in 95%, and 79.5% of patients presented in a good clinical condition on follow-up (modified Rankin Scale 0 or 1). Microsurgical treatment is recommended if the lesion is accessible and angioarchitectural risk factors favor definitive treatment.

Intramedullary spinal cavernoma: clinical presentation, microsurgical approach, and long-term outcome in a cohort of 48 patients.

OBJECT Intramedullary spinal cavernoma (ISC) is a rare entity and accounts for approximately 5%-12% of all spinal vascular pathologies. The purpose of the present study was to examine the influence of clinical presentation, localization, and different surgical approaches on long-term outcome in patients treated for ISC. METHODS The authors performed a retrospective single-center study of 48 cases of ISC treated microsurgically over the past 28 years. Analyzed factors included preoperative clinical history, microsurgical strategies, neurological outcome (American Spinal Injury Association [ASIA] grade, Epstein and Cooper grade), and the occurrence of postoperative spinal ataxia. Univariate analysis was performed to identify factors influencing long-term outcome. RESULTS Preoperatively, 18.8% of all patients experienced a slow, progressive decline in neurological function and 33.3% suffered repetitive episodes of acute neurological deterioration over a time frame of months to years. Moreover, 16.7% noted the sudden onset of a severe neurological deficit, whereas 25% experienced the sudden onset of symptoms with a subsequent gradually progressive decline in neurological function. On long-term follow-up after treatment (mean ± SD, 79.3 ± 35.2 months), 70.8% of patients showed no change in neurological function, 6.3% suffered from a decline, and 22.9% improved neurologically. Thoracolumbar localization (p = 0.043), low preoperative Epstein and Cooper grade for the lower extremities (p < 0.001), and a low preoperative ASIA grade (p < 0.001) were identified as factors associated with an unfavorable outcome (ASIA Grade A-C). The rate of spinal ataxia related to surgical approach was 16.7%. CONCLUSION Postoperative neurological function in ISC patients is determined by the preoperative neurological status. On long-term follow-up after microsurgical treatment, 93.7% of patients presented with a stable or improved condition (ASIA grade); thus, definite microsurgical treatment should be considered as long as patients present with only mild symptoms after the diagnosis of symptomatic ISC.

Impact of intraventricular hemorrhage measured by Graeb and LeRoux score on case fatality risk and chronic hydrocephalus in aneurysmal subarachnoid hemorrhage.

BACKGROUND: Reliable prognostic tools to estimate the case fatality rate (CFR) and the development of chronic hydrocephalus (CHC) in aneurysmal subarachnoid hemorrhage (SAH) are not well defined. This study aims to investigate the practicability and reliability of Fisher, Graeb, and LeRoux scores for SAH patient prognosis. METHODS: A total of 206 patients with aneurysmal SAH were retrospectively analyzed in prediction of CFR and CHC. Clinical data was evaluated and grading was performed using Fisher, Graeb, and LeRoux scores. Univariate and multivariate analyses were performed to identify relevant predictive parameters. RESULTS: CFR was 17.0 % and was associated with higher age, higher Hunt & Hess (H&H) grade, lower Glasgow Coma Scale (GCS) at admission, as well as a higher Fisher, Graeb, and LeRoux score (p < 0.001). There were 19.9 % that developed CHC requiring permanent cerebrospinal fluid diversion. Low initial GCS (p = 0.003), high H&H (p < 0.001), intracerebral hematoma (p = 0.003), high Fisher (p = 0.047), Graeb and LeRoux scores (p < 0.001) were associated with a higher rate of ventricular-peritoneal shunting (VPS) in surviving patients. In multivariate analyses, Graeb score (odds ratio (OR) 1.183 [1.027, 1.363], p = 0.020), LeRoux score (OR 1.120 [1.013-1.239, p = 0.027), and H&H (OR 2.715 [1.496, 4.927], p = 0.001) remained independent prognostic factors for VPS. CONCLUSIONS: Graeb or LeRoux scores improve the prediction of shunt dependency and in parts of CFR in aneurysmal SAH patients therefore confirming the relevance of the extent and distribution of intraventricular blood for the clinical course in SAH.

Correlation of oxygenation and perfusion sensitive MRI with invasive micro probe measurements in healthy mice brain.

The non-invasive assessment of (patho-)physiological parameters such as, perfusion and oxygenation, is of great importance for the characterization of pathologies e.g., tumors, which may be helpful to better predict treatment response and potential outcome. To better understand the influence of physiological parameters on the investigated oxygenation and perfusion sensitive MRI methods, MRI measurements were correlated with subsequent invasive micro probe measurements during free breathing conditions of air, air+10% CO2 and 100% O2 in healthy mice brain. MRI parameters were the irreversible (R2), reversible (R2') and effective (R2*) transverse relaxation rates, venous blood oxygenation level assessed by quantitative blood oxygenation level dependent (qBOLD) method and cerebral blood flow (CBF) assessed by arterial spin labeling (ASL) using a 7 T small animal MRI scanner. One to two days after MRI, tissue perfusion and pO2 were measured by Laser-Doppler flowmetry and fluorescence quenching micro probes, respectively. The tissue pO2 values were converted to blood oxygen saturation by using the Hill equation. The animals were anesthetized by intra peritoneal injection of ketamine-xylazine-acepromazine (10-2-0.3 mg/ml · kg). Results for normal/hypercapnia/hyperoxia conditions were: R2[s(∧)-1] = 20.7/20.4/20.1, R2*[s(∧)-1] = 31.6/29.6/25.9, R2'[s-(∧)1] = 10.9/9.2/5.7, qBOLD venous blood oxygenation level = 0.43/0.51/0.56, CBF[ml · min(∧)-1 · 100 g(∧)-1] = 70.6/105.5/81.8, Laser-Doppler flowmetry[a.u.] = 89.2/120.2/90.6 and pO2[mmHg] = 6.3/32.3/46.7. All parameters were statistically significantly different with P < 0.001 between all breathing conditions. All MRI and the corresponding micro probe measurements were also statistically significantly (P ≤ 0.03) correlated with each other. However, converting the tissue pO2 to blood oxygen saturation = 0.02/0.34/0.63, showed only very limited agreement with the qBOLD venous blood oxygenation level. We found good correlation between MRI and micro probe measurements. However, direct conversion of tissue pO2 to blood oxygen saturation by using the Hill equation is very limited. Furthermore, adverse effects of anesthesia and trauma due to micro probe insertion are strong confounding factors and need close attention for study planning and conduction of experiments. Investigation of the correlation of perfusion and oxygenation sensitive MRI methods with micro probe measurements in pathologic tissue such as tumors is now of compelling interest.

Intranasal delivery of neural stem/progenitor cells: a noninvasive passage to target intracerebral glioma.

Stem cell-based therapies for neurological disorders, including brain tumors, advance continuously toward clinical trials. Optimized cell delivery to the central nervous system remains a challenge since direct intracerebral injection is an invasive method with low transplantation efficiency. We investigated the feasibility of intranasal administration of neural stem/progenitor cells (NSPCs) as an alternative, noninvasive, and direct passage for the delivery of stem cells to target malignant gliomas. Tumor-targeting and migratory pathways of murine and human NSPCs were investigated by intravital magnetic resonance imaging and in histological time course analyses in the intracerebral U87, NCE-G55T2, and syngenic Gl261 glioblastoma models. Intranasally administered NSPCs displayed a rapid, targeted tumor tropism with significant numbers of NSPCs accumulating specifically at the intracerebral glioma site within 6 hours after intranasal delivery. Histological time series analysis revealed that NSPCs migrated within the first 24 hours mainly via olfactory pathways but also by systemic distribution via the microvasculature of the nasal mucosa. Intranasal application of NSPCs leads to a rapid, targeted migration of cells toward intracerebral gliomas. The directional distribution of cells accumulating intra- and peritumorally makes the intranasal delivery of NSPCs a promising noninvasive and convenient alternative delivery method for the treatment of malignant gliomas with the possibility of multiple dosing regimens.

Clinical relevance of associated aneurysms with arteriovenous malformations of the posterior fossa.

The aim of this study was to determine the frequency of aneurysms associated with arteriovenous malformations (AVMs) of the posterior fossa and their relation to hemorrhagic presentation in comparison to supratentorial AVMs. We performed a retrospective analysis of 474 patients with intracranial AVMs treated in our center from 1990 to 2010. Patients were analyzed for AVM size, drainage type and their clinical course with focus on vessel anomalies including AVM-associated aneurysms. Seventeen (30%) of 57 posterior fossa AVMs versus 46 (11%) of 417 supratentorial AVMs were associated with aneurysms. In six (10.5%) versus seven (1.7%) patients, respectively, flow-associated aneurysms were the source of hemorrhage. Infratentorial location of an AVM was a significant risk factor for the incidence (p < 0.001) and rupture (p < 0.001) of AVM-associated aneurysms. Feeding artery aneurysms in particular represented a risk factor for hemorrhage in the overall group of AVM patients, independently of the location (p < 0.001). The majority of patients with a posterior fossa AVM were treated by combined embolization and surgical removal within one procedure (n = 33, 58%). Feeding artery aneurysms were excluded by endovascular coiling or surgical clipping whenever feasible. Overall treatment-associated permanent morbidity in the subgroup of posterior fossa AVMs was 11% (n = 6) and mortality 4% (n = 2). Posterior fossa AVMs display a significantly higher frequency of associated aneurysms of the adjacent vessels that are correlated to the high bleeding rate compared to AVMs of the supratentorial compartment. We therefore recommend aggressive AVM treatment including the exclusion of associated aneurysms as a minimal therapeutic goal whenever possible.