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  • Author or Editor: Susan M. Fiorex
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Intraspinal psammomatous melanotic schwannoma not associated with Carney complex: case report

Saman Shabani, Susan M. Fiore, Roberta Seidman, and Raphael P. Davis

The authors present a case of intraspinal malignant psammomatous melanotic schwannoma (PMS) not associated with Carney complex and review all reported cases not associated with this syndrome. The focus of this review paper is on the characteristics of the malignant progression of PMS.

A 54-year-old man had a history of squamous cell carcinoma of the neck and tonsillar carcinoma. The patient’s serial CT scanning study showed a mass in the left C-5 foramen. On presentation he was neurologically intact. After 18 months, the patient developed radiating pain down the left arm with decreased sensation. MRI of the cervical spine showed an enhancing 2.1 × 1.5 × 1.9-cm mass in the left C5–6 foramen. A C5–6 hemilaminectomy was performed with gross-total removal of the tumor. At 3 months postoperatively, the patient developed new-onset pain and weakness. MRI showed a dumbbell-shaped mass in the left C-7 foramen. MRI of the pelvis showed a 1.4 × 1.0-cm lesion on the right ischium and a 1.1 × 2.8-cm lesion on the right inferior pubic ramus. Anterior cervical discectomy of C5–6 and C6–7 with corpectomy of C-6 with subtotal resection of the tumor was completed. PMS should not be considered a benign tumor because in 41.1% of patients, including the patient in this report, the tumor progresses to malignancy. Long-term follow-up is needed in these patients. New surgical treatment plans should be considered.

InJournal of Neurosurgery: Spine Volume 23 (2015): Issue 2 (Aug 2015)

Open access

A quantitative model of the cerebral windkessel and its relevance to disorders of intracranial dynamics

Michael Egnor, Liu Yang, Racheed M. Mani, Susan M. Fiore, and Petar M. Djurić

OBJECTIVE

Traditional models of intracranial dynamics fail to capture several important features of the intracranial pressure (ICP) pulse. Experiments show that, at a local amplitude minimum, the ICP pulse normally precedes the arterial blood pressure (ABP) pulse, and the cranium is a band-stop filter centered at the heart rate for the ICP pulse with respect to the ABP pulse, which is the cerebral windkessel mechanism. These observations are inconsistent with existing pressure-volume models.

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To explore these issues, the authors modeled the ABP and ICP pulses by using a simple electrical tank circuit, and they compared the dynamics of the circuit to physiological data from dogs by using autoregressive with exogenous inputs (ARX) modeling.

RESULTS

The authors’ ARX analysis showed close agreement between the circuit and pulse suppression in the canine cranium, and they used the analogy between the circuit and the cranium to examine the dynamics that underlie this pulse suppression.

CONCLUSIONS

This correspondence between physiological data and circuit dynamics suggests that the cerebral windkessel consists of the rhythmic motion of the brain parenchyma and CSF that continuously opposes systolic and diastolic blood flow. Such motion has been documented with flow-sensitive MRI. In thermodynamic terms, the direct current (DC) power of cerebral arterial perfusion drives smooth capillary flow and alternating current (AC) power shunts pulsatile energy through the CSF to the veins. This suggests that hydrocephalus and related disorders are disorders of CSF path impedance. Obstructive hydrocephalus is the consequence of high CSF path impedance due to high resistance. Normal pressure hydrocephalus (NPH) is the consequence of high CSF path impedance due to low inertance and high compliance. Low-pressure hydrocephalus is the consequence of high CSF path impedance due to high resistance and high compliance. Ventriculomegaly is an adaptive physiological response that increases CSF path volume and thereby reduces CSF path resistance and impedance. Pseudotumor cerebri is the consequence of high DC power with normal CSF path impedance. CSF diversion by shunting is an accessory windkessel—it drains energy (and thereby lowers ICP) and lowers CSF path resistance and impedance. Cushing’s reflex is an accessory windkessel in extremis—it maintains DC power (arterial hypertension) and reduces AC power (bradycardia). The windkessel theory is a thermodynamic approach to the study of energy flow through the cranium, and it points to a new understanding of hydrocephalus and related disorders.

InJournal of Neurosurgery: Pediatrics Volume 32: Issue 3 (Sep 2023)

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Modeling the return to consciousness after severe traumatic brain injury at a large academic level 1 trauma center

Nathan J. Winans, Justine J. Liang, Bradley Ashcroft, Stephen Doyle, Adam Fry, Susan M. Fiore, Sima Mofakham, and Charles B. Mikell

OBJECTIVE

严重创伤性脑损伤(sTBI)价格ficant morbidity and mortality. It remains difficult to counsel families on functional prognosis and plan research initiatives aimed at treating traumatic coma. In order to better address these problems, the authors set out to develop statistical models using retrospective data to identify admission characteristics that correlate with time until the return of consciousness, defined as the time to follow commands (TFC). These results were then used to create a TFC score, allowing for rapid identification of patients with predicted prolonged TFC.

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Data were reviewed and collected from medical records of sTBI patients with Glasgow Coma Scale (GCS) motor subscores ≤ 5 who were admitted to Stony Brook University Hospital from January 2011 to July 2018. Data were used to calculate descriptive statistics and build binary logistic regression models to identify admission characteristics that correlated with in-hospital mortality and in-hospital command-following. A Cox proportional hazards model was used to identify admission characteristics that correlated with the length of TFC. A TFC score was developed using the significant variables identified in the Cox regression model.

RESULTS

There were 402 adult patients who met the inclusion criteria for this study. The average age was 50.5 years, and 122 (30.3%) patients were women. In-hospital mortality was associated with older age, higher Injury Severity Score (ISS), higher Rotterdam score (head CT grading system), and the presence of bilateral fixed and dilated pupils (p < 0.01). In-hospital command-following was anticorrelated with age, ISS, Rotterdam score, and the presence of a single fixed and dilated pupil (p < 0.05). TFC was anticorrelated with age, ISS, Rotterdam score, and the presence of a single fixed and dilated pupil. Additionally, patients who sustained injuries from falls from standing height had a shorter average TFC. The 3 significant variables from the Cox regression model that explained the most variance were used to create a 4-point TFC score. The most significant of these characteristics were Rotterdam head CT scores, high impact traumas, and the presence of a single fixed and dilated pupil. Importantly, the presence of a single fixed and dilated pupil was correlated with longer TFC but no increase in likelihood of in-hospital mortality.

CONCLUSIONS

4点的创建交通得分allow clinicians to quickly identify patients with predicted prolonged TFC and estimate the likelihood of command-following at different times after injury. Discussions with family members should take into account the likelihood that patients will return to consciousness and survive after TBI.

InJournal of Neurosurgery Volume 133: Issue 2 (Aug 2020)

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