Elevated intracranial pressure and reversible eye-tracking changes detected while viewing a film clip.

OBJECTIVE The precise threshold differentiating normal and elevated intracranial pressure (ICP) is variable among individuals. In the context of several pathophysiological conditions, elevated ICP leads to abnormalities in global cerebral functioning and impacts the function of cranial nerves (CNs), either or both of which may contribute to ocular dysmotility. The purpose of this study was to assess the impact of elevated ICP on eye-tracking performed while patients were watching a short film clip. METHODS Awake patients requiring placement of an ICP monitor for clinical purposes underwent eye tracking while watching a 220-second continuously playing video moving around the perimeter of a viewing monitor. Pupil position was recorded at 500 Hz and metrics associated with each eye individually and both eyes together were calculated. Linear regression with generalized estimating equations was performed to test the association of eye-tracking metrics with changes in ICP. RESULTS Eye tracking was performed at ICP levels ranging from -3 to 30 mm Hg in 23 patients (12 women, 11 men, mean age 46.8 years) on 55 separate occasions. Eye-tracking measures correlating with CN function linearly decreased with increasing ICP (p < 0.001). Measures for CN VI were most prominently affected. The area under the curve (AUC) for eye-tracking metrics to discriminate between ICP < 12 and ≥ 12 mm Hg was 0.798. To discriminate an ICP < 15 from ≥ 15 mm Hg the AUC was 0.833, and to discriminate ICP < 20 from ≥ 20 mm Hg the AUC was 0.889. CONCLUSIONS Increasingly elevated ICP was associated with increasingly abnormal eye tracking detected while patients were watching a short film clip. These results suggest that eye tracking may be used as a noninvasive, automatable means to quantitate the physiological impact of elevated ICP, which has clinical application for assessment of shunt malfunction, pseudotumor cerebri, concussion, and prevention of second-impact syndrome.

Utility of positron emission tomography in schwannomatosis.

Schwannomatosis is characterized by multiple non-intradermal schwannomas with patients often presenting with a painful mass in their extremities. In this syndrome malignant transformation of schwannomas is rare in spite of their large size at presentation. Non-invasive measures of assessing the biological behavior of plexiform neurofibromas in neurofibromatosis type 1 such as positron emission tomography (PET), CT scanning and MRI are well characterized but little information has been published on the use of PET imaging in schwannomatosis. We report a unique clinical presentation portraying the use of PET imaging in schwannomatosis. A 27-year-old woman presented with multiple, rapidly growing, large and painful schwannomas confirmed to be related to a constitutional mutation in the SMARCB1 complex. Whole body PET/MRI revealed numerous PET-avid tumors suggestive of malignant peripheral nerve sheath tumors. Surgery was performed on multiple tumors and none of them had histologic evidence of malignant transformation. Overall, PET imaging may not be a reliable predictor of malignant transformation in schwannomatosis, tempering enthusiasm for surgical interventions for tumors not producing significant clinical signs or symptoms.

Preoperative Predictors of Spinal Infection within the National Surgical Quality Inpatient Database.

BACKGROUND: Surgical-site infections (SSIs) are a major cause of morbidity and mortality, increasing the length and cost of hospitalization. In patients undergoing spine surgery, there are limited large-scale data on patient-specific risk factors for SSIs. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database was reviewed for all spinal operations between 2006 and 2012. The rates of 30-day SSIs were calculated, and univariate analysis of selected preoperative risk factors was performed. Multivariate analysis was then used to identify independent predictors of SSIs. RESULTS: A total of 1110 of the 60,179 patients (1.84%) had a postoperative wound infection. There were 527 (0.87%) deep and 590 (0.98%) superficial infections. Patients with infections had greater rates of sepsis, longer lengths of stay, and more return visits to the operating room. Independent predictors of infection were female sex, inpatient status, insulin-dependent diabetes, preoperative steroid use greater than 10 days, hematocrit less than 35, body mass index greater than 30, wound class, American Society of Anesthesiologists class, and operative duration. CONCLUSIONS: Analysis of a large national patient database revealed many independent risk factors for SSIs after spinal surgery. Some of these risk factors can be modified preoperatively to reduce the risk of postoperative infection.

Association of Steroid Use with Deep Venous Thrombosis and Pulmonary Embolism in Neurosurgical Patients: A National Database Analysis.

OBJECTIVE: Venous thromboembolism (VTE) is a major preventable cause of morbidity and mortality in hospitalized patients and is a widely accepted measure for quality of care. Prolonged corticosteroid therapy, which is common in neurosurgical patients, has been associated with VTE. Using a national database, we sought to determine whether corticosteroid use for >10 days was an independent risk factor for deep venous thrombosis (DVT) and pulmonary embolism (PE). METHODS: The well-validated American College of Surgeons National Surgical Quality Improvement Program database was queried to evaluate the rates of VTE during the period 2006-2013 in patients undergoing neurosurgical procedures. A multivariate regression model was constructed to assess the effect of prolonged corticosteroid use on the occurrence of PE and DVT by postoperative day 30. RESULTS: Of 94,620 patients identified, 565 (0.60%) developed PE and 1057 (1.12%) developed DVT within 30 days after surgery. In the multivariate model, patients receiving corticosteroids were significantly more likely to have PE (odds ratio = 1.47, 95% confidence interval = 1.13-1.90, P = 0.004) and DVT (odds ratio = 1.55, 95% confidence interval = 1.28-1.87, P < 0.001). Other factors independently associated with development of PE and DVT included the presence of malignancy, longer hospitalization, certain infections (including pneumonia and urinary tract infections), and stroke with a neurologic deficit. CONCLUSIONS: In the neurosurgical population, prolonged courses of corticosteroids are associated with an increased risk of developing postoperative DVT and PE, even when controlling for potential confounders.