Postoperative Admission of Adult Craniotomy Patients to the Neuroscience Ward Reduces Length of Stay and Cost.

BACKGROUND: The neurointensive care unit (NICU) has traditionally been the default recovery unit after elective craniotomies. OBJECTIVE: To assess whether admitting adult patients without significant comorbidities to the neuroscience ward (NW) instead of NICU for recovery resulted in similar clinical outcome while reducing length of stay (LOS) and hospitalization cost. METHODS: We retrospectively analyzed the clinical and cost data of adult patients undergoing supratentorial craniotomy at a university hospital within a 5-yr period who had a LOS less than 7 d. We compared those admitted to the NICU for 1 night of recovery versus those directly admitted to the NW. RESULTS: The NICU and NW groups included 340 and 209 patients, respectively, and were comparable in terms of age, ethnicity, overall health, and expected LOS. NW admissions had shorter LOS (3.046 vs 3.586 d, P < .001), and independently predicted shorter LOS in multivariate analysis. While the NICU group had longer surgeries (6.8 vs 6.4 h), there was no statistically significant difference in the cost of surgery. The NW group was associated with reduced hospitalization cost by $3193 per admission on average (P < .001). Clinically, there were no statistically significant differences in the rate of return to Operating Room, Emergency Department readmission, or hospital readmission within 30 d. CONCLUSION: Admitting adult craniotomy patients without significant comorbidities, who are expected to have short LOS, to NW was associated with reduced LOS and total cost of admission, without significant differences in postoperative clinical outcome.

A method for optimizing EEG electrode number and configuration for signal acquisition in P300 speller systems.

OBJECTIVE: The P300 speller is intended to restore communication to patients with advanced neuromuscular disorders, but clinical implementation may be hindered by several factors, including system setup, burden, and cost. Our goal was to develop a method that can overcome these barriers by optimizing EEG electrode number and placement for P300 studies within a population of subjects. METHODS: A Gibbs sampling method was developed to find the optimal electrode configuration given a set of P300 speller data. The method was tested on a set of data from 15 healthy subjects using an established 32-electrode pattern. Resulting electrode configurations were then validated using online prospective testing with a naïve Bayes classifier in 15 additional healthy subjects. RESULTS: The method yielded a set of four posterior electrodes (PO8, PO7, POZ, CPZ), which produced results that are likely sufficient to be clinically effective. In online prospective validation testing, no significant difference was found between subjects' performances using the reduced and the full electrode configurations. CONCLUSIONS: The proposed method can find reduced sets of electrodes within a subject population without reducing performance. SIGNIFICANCE: Reducing the number of channels may reduce costs, set-up time, signal bandwidth, and computation requirements for practical online P300 speller implementation.

Integrating language information with a hidden Markov model to improve communication rate in the P300 speller.

The P300 speller is a common brain-computer interface (BCI) application designed to communicate language by detecting event related potentials in a subject's electroencephalogram (EEG) signal. Information about the structure of natural language can be valuable for BCI communication systems, but few attempts have been made to incorporate this domain knowledge into the classifier. In this study, we treat BCI communication as a hidden Markov model (HMM) where hidden states are target characters and the EEG signal is the visible output. Using the Viterbi algorithm, language information can be incorporated in classification and errors can be corrected automatically. This method was first evaluated offline on a dataset of 15 healthy subjects who had a significant increase in bit rate from a previously published naïve Bayes approach and an average 32% increase from standard classification with dynamic stopping. An online pilot study of five healthy subjects verified these results as the average bit rate achieved using the HMM method was significantly higher than that using the naïve Bayes and standard methods. These findings strongly support the integration of domain-specific knowledge into BCI classification to improve system performance and accuracy.

Identification of knowledge gaps in neurosurgery through analysis of responses to the Self-Assessment in Neurological Surgery (SANS).

OBJECTIVE: To examine the gaps in knowledge of neurosurgeons responding to the Self-Assessment in Neurological Surgery (SANS). METHODS: From 2008-2010, 267 neurosurgery residents and 993 attending neurosurgeons completed the 245 available question in SANS. Mean scores were calculated and assessed according to 18 major neurosurgical knowledge disciplines. Statistical analysis was carried out to evaluate for knowledge gaps among all users and differences in performance between residents and practicing neurosurgeons. RESULTS: The mean overall score was 66% ± 12. Of the 18 major knowledge categories in SANS, respondents answered questions incorrectly ≥ 30% of the time in half of the categories. Mean scores in anatomy (76%) were the highest, and mean scores in vascular (60%) were the lowest (P < 0.001). The mean score per category was significantly higher for practicing neurosurgeons (71.5% ± 8.9) than residents (60.5% ± 12.6; P < 0.001). Residents answered questions incorrectly ≥ 30% of the time in all 18 categories versus 7 categories for attending neurosurgeons. Among residents, the highest mean scores were achieved in anatomy and the lowest were achieved in vascular (P < 0.001); this differential response was also reflected among attending neurosurgeons. CONCLUSIONS: SANS demonstrated areas of knowledge gaps in a broad group of neurosurgeons. There were also significant differences between residents and attending neurosurgeons. Identification of areas of deficiency could prove useful in future educational endeavors.

Identification of knowledge gaps in neurosurgery using a validated self-assessment examination: differences between general and spinal neurosurgeons.

OBJECTIVE: The practice of neurosurgery requires fundamental knowledge base. Residency training programs and continuing medical education courses are designed to teach relevant neurosurgical principles. Nevertheless, knowledge gaps exist for neurosurgeons and may be different between cohorts of neurosurgeons. The Self-Assessment in Neurological Surgery (SANS) General Examination and Spine Examination are online educational tools for lifelong learning and maintenance of certification. This study examines the gaps in knowledge of spinal neurosurgeons and general neurosurgeons taking SANS. METHODS: From 2008 to 2010, a total of 165 spinal neurosurgeons completed the 243 available questions of the SANS Spine Examination. Over that same time frame, 993 general neurosurgeons completed the SANS General Spine Examination. Mean scores were calculated and assessed according to 18 major neurosurgical knowledge disciplines. Statistical analysis was carried out to evaluate for significant knowledge gaps among all users and significant differences in performance between spinal neurosurgeons and their general neurosurgeon counterparts. RESULTS: The mean overall examination score was 87.4% ± 7.5% for spinal neurosurgeons and 71.5% ± 8.9% for general neurosurgeons (P < 0.001). Of the 18 major knowledge categories in SANS, spinal neurosurgeons (n = 165) answered questions incorrectly 15% or greater of the time in five of the categories. The categories of lower performance for spinal neurosurgeons were cerebrovascular, anesthesia and critical care, general clinical, tumor, and trauma. For general neurosurgeons (n = 993), the five knowledge categories with lowest performance were cerebrovascular, epilepsy, peripheral nerve, trauma, and radiosurgery. Although spinal neurosurgeons and general neurosurgeons shared some areas of decreased performance including trauma and cerebrovascular, spine neurosurgeons relatively underperformed in general clinical, anesthesia and critical care, and tumor. CONCLUSIONS: The SANS Spine Examination demonstrated knowledge gaps in specific categories for spinal surgeons. The knowledge areas of diminished performance differed between spinal and general neurosurgeons. Identification of specific areas of deficiency could prove useful in the design and implementation of educational programs and maintenance of certification.

MR imaging characteristics of oligodendroglial tumors with assessment of 1p/19q deletion status.

PURPOSE: Patients with oligodendrogliomas with allelic loss of chromosomal arm 1p and 19q have been shown, especially with anaplastic oligodendrogliomas, to have both a better initial and long-term response to chemotherapy as well as an improved overall survival. Effective treatment of patients with brain tumors requires accurate diagnostic techniques. MR imaging can be used to help differentiate between low- and high-grade tumors. We hypothesize that certain MR imaging characteristics can be used to differentiate between patients with and without 1p and 19q deletion. METHODS: Using the clinical database at the University of Virginia Neuro-Oncology Center, we identified adult patients with grade II and III oligodendroglial tumors who underwent treatment from 2002 to 2007. Age at diagnosis, gender, tumor grade, chromosomal deletion status, duration of follow-up, and MR imaging characteristics were analyzed; the latter was read by a blinded neuroradiologist. RESULTS: One hundred and four patients met the inclusion criteria. Of these patients, 44 manifested 1p/19q co-deletion and 60 patients lacked this deletion. The greatest cross-sectional area (mean) of the tumor measured 23.4 cm(2) for patients with the co-deletion and 31.7 cm(2) for patients with intact alleles (p = 0.008). In addition, inner table thinning was noted directly adjacent to seven tumors with intact 1p and 19q alleles and in no tumors with the 1p/19q co-deletion (p = 0.020). Amongst patients with pure oligodendrogliomas, those with 1p/19q co-deletion had tumors more often confined to a single lobe as compared with those patients without the co-deletion (p = 0.023). Finally, tumors with intact alleles were more often found in the temporal lobe (45.0%) as compared with co-deleted tumors (22.7%) (p = 0.011). CONCLUSION: MR imaging is a valuable imaging modality for differentiating between oligodendrogliomas with or without the 1p/19q deletion. While imaging will never replace definitive tissue diagnosis, imaging characteristics such as tumor size, location, and overlying skull thinning can assist clinicians in assessing patients with oligodendroglial tumors prior to surgical or medical intervention.