To evauluate our novel ultrasound model for measurement of optic nerve sheath diameter (ONSD) and determine the intra- and inter-operator variability associated with this technique.

We conducted ten measurements of ONSD per model amongst eight different models with a single experienced operator to examine intra-operator variability. Similarly, we had seven different operators measure the OSND twice in eight different models, in order to determine inter-operator variability analyzed with a three level linear statistical model.

For intra-operator variability, the intra-cluster correlation coefficients for the experienced and novice operators were 0.643 and 0.453 respectively. This displayed improvement in intra-operator variability with experience. The inter-cluster correlation coefficient was 0 for the group of novice operators, indicating negligible difference amongst multiple operators in measuring any given model of ONSD. A strong, statistically significant, linear relationship between the actual model disc size and the ultrasound ONSD measures was identified, implying the reliability of the images produced by our novel model.

Utilizing a novel model for ONSD ultrasonography, we have determined the intraoperator reliability of ONSD measurement to be moderate, with no appreciable difference amongst multiple operators. Improvement in measurement reliability has been demonstrated between expert and novice operators with our model, indicating the potential benefit of simulation platforms for teaching the technique of ONSD ultrasound.

To define the incidence of new contralateral intracranial lesions following decompressive hemicraniectomy for blunt traumatic brain injury, and explore the potential association with metabolic factors that contribute to coagulopathy.

We retrospectively reviewed the records and imaging of all patients treated with hemicraniectomy for blunt traumatic brain injury at our institution from May 2007 up to and including January 2012.

Twenty patients were identified during the time period to have undergone decompressive craniectomy for blunt head injury. The average age and Glasgow Coma Scale on presentation was 44.1 years (range: 19 – 72 years) and 6.5 (range: 3 – 14) respectively. All but one patient presented with an extra-axial hematoma as their surgical indication for craniectomy. Seven patients (35.0%) developed new contralateral lesions post-craniectomy. The average peri-operative pH, bicarbonate (HCO3) and hematocrit (HCT) levels for those with new contralateral lesions were lower than those without new lesions. Five of the seven patients (71.4%) with new lesions had abnormalities on their laboratory results that have been know to be attributable to coagulopathy, with four (57.1%) having two or more abnormal results. Eight of 13 (61.5%) patients without new lesion had laboratory abnormalites, with five (38.5%) having two or more abnormalities identified.

The incidence of new contralateral lesions post-craniectomy for blunt head injury is 35.0% in our experience. There is an association between the metabolic derangements linked to trauma related coagulopathy and the formation of new lesions.

To review our institutional experience with Gamma Knife (GK) stereotactic radiosurgery in treating focally recurrent high grade glial neoplasms of World Health Organization (WHO) grade III or IV.

We conducted a retrospective cohort review of all patients treated with GK for focally recurrent high grade gliomas at our institution between November 2003 and April 2013. Data on age, sex, tumor volume, location and maximal diameter, presenting clinical status, complications and clinical outcome was recorded.

A total of 33 patients were identified. Four were lost to follow-up. Average post-GK and overall survival was 20.4 months (range: 3 – 72) and 63.3 months (range: 10 – 214) respectively. For WHO grade IV gliomas, the average post-GK and overall survival was 15.8 months (range: 3 – 77) and 40.1 months (range: 13 – 148) respectively. Similarily, for WHO grade III gliomas, the average post-GK and overall survival was 34.9 months (range: 6 – 72) and 136.4 months (range: 22 – 214) respectively. Twenty-two patients (75.9%) had post-GK edema, with 14 requiring dexamethasone and eight being asymptomatic. Four patients (13.8%) had imaging defined radiation necrosis.

Gamma Knife SRS affords an extension of local tumor control, acceptable morbidity, and potentially prolonged survival, for highly selected patients with focally recurrent high grade glial neoplasms.