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  • Author or Editor: Michael C Brown x
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Mark P. Piedra, Paul D. Brown, Paul C. Carpenter and Michael J. Link

✓ The authors present the case of a 58-year-old woman who presented with symptoms of diabetes insipidus (DI) 1 year after she was found to have a Stage 3 (of 4) estrogen receptor—positive infiltrating ductal adenocarcinoma of the left breast with pulmonary and bone metastases. Magnetic resonance images demonstrated a solitary site of metastasis in the patient's pituitary stalk, and gamma knife surgery (GKS) was performed to treat the lesion. Three months after GKS the patient was able to reduce the medication she required for the DI. There was no evidence of pituitary failure and no negative effect on her vision.

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Robert D. Brown Jr., David O. Wiebers, James C. Torner and W. Michael O'Fallon

✓ The purpose of this study was to determine the symptoms at presentation and the incidence of intracranial hemorrhage (ICrH) caused by intracranial vascular malformations (IVMs) in a defined population. The authors used the Mayo Clinic medical records linkage system to detect all cases of IVM among residents of Olmsted County, Minnesota, during the period 1965 through 1992. Forty-eight IVMs were detected over the 27-year period. Twenty-nine of the 48 patients were symptomatic at presentation. The most common presenting symptom was ICrH, which was present in 20 patients, 69% of all symptomatic cases. Sixty-five percent of arteriovenous malformations (AVMs) presented with ICrH. The most common subtype of ICrH was intracerebral hemorrhage, which was found in nine of 20 patients; the second most common subtype was subarachnoid hemorrhage. The peak occurrence of hemorrhage was during the fifth decade of life. The age- and gender-adjusted occurrence of a first ICrH from an IVM among residents of Olmsted County, Minnesota was 0.82 per 100,000 person years (95% confidence interval 0.46–1.19). There was no increase in the detection of IVM-related ICrH throughout the study period. The 30-day mortality rate following ICrH was 17.6% for patients with an AVM and 25% for all patients with IVMs. This study provides unique data on symptoms at presentation and the incidence of ICrH and hemorrhage subtypes from IVMs on a population basis.

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Mark C. Preul, Phillip B. Long, Jeffrey A. Brown, Manuel E. Velasco and Michael T. Weaver

✓ The histopathological and autonomic effects of percutaneous trigeminal ganglion compression for trigeminal neuralgia were studied in New Zealand White rabbits. Drops in mean arterial blood pressure of 38% and in heart rate of 30% were observed during compression (p < 0.0001). Corneal reflex, pinprick sensation, and mastication strength were intact in 13 of 14 rabbits after compression. These findings resembled the effects of percutaneous compression in humans and suggested that the New Zealand White rabbit is a useful model for the study of percutaneous compression.

Trigeminal sensory roots and ganglia from 14 rabbits killed at intervals from 1 to 84 days after percutaneous compression were sectioned and stained using immunoperoxidase for neurofilaments, hematoxylin and eosin, luxol fast blue, and cresyl echt violet. Focal axonal damage and demyelination were present 7 days after compression. No difference could be detected in the perikaryonal distribution of neurofilaments between compressed and control trigeminal ganglia. Focal demyelination and Schwann cell proliferation preceding remyelination were present in the trigeminal sensory root at 84 days. Differential injury of axons compared to trigeminal ganglion cell bodies suggests that axonal regeneration is possible and may contribute to the recovery of motor and sensory function in patients after percutaneous compression.

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Martina Stippler, Veronica Ortiz, P. David Adelson, Yue-Fang Chang, Elizabeth C. Tyler-Kabara, Stephen R. Wisniewski, Ericka L. Fink, Patrick M. Kochanek, S. Danielle Brown and Michael J. Bell

Object

Minimizing secondary brain injuries after traumatic brain injury (TBI) in children is critical to maximizing neurological outcome. Brain tissue oxygenation monitoring (as measured by interstitial partial pressure of O2 [PbO2]) is a new tool that may aid in guiding therapies, yet experience in children is limited. This study aims to describe the authors' experience of PbO2 monitoring after TBI. It was hypothesized that PbO2 thresholds could be established that were associated with favorable neurological outcome, and it was determined whether any relationships between PbO2 and other important clinical variables existed.

Methods

Forty-six children with severe TBI (Glasgow Coma Scale score ≤ 8 after resuscitation) who underwent PbO2 and brain temperature monitoring between September 2004 and June 2008 were studied. All patients received standard neurocritical care, and 24 were concurrently enrolled in a trial of therapeutic early hypothermia (n = 12/group). The PbO2 was measured in the uninjured frontal cortex. Hourly recordings and calculated daily means of various variables including PbO2, intracranial pressure (ICP), cerebral perfusion pressure (CPP), mean arterial blood pressure, partial pressure of arterial O2, and fraction of inspired O2 were compared using several statistical approaches. Glasgow Outcome Scale scores were determined at 6 months after injury.

Results

The mean patient age was 9.4 years (range 0.1–16.5 years; 13 girls) and 8554 hours of monitoring were analyzed (PbO2 range 0.0–97.2 mm Hg). A PbO2 of 30 mm Hg was associated with the highest sensitivity/specificity for favorable neurological outcome at 6 months after TBI, yet CPP was the only factor that was independently associated with favorable outcome. Surprisingly, instances of preserved PbO2 with altered ICP and CPP were observed in some children with unfavorable outcomes.

Conclusions

Monitoring of PbO2 demonstrated complex interactions with clinical variables reflecting intracranial dynamics using this protocol. A higher threshold than reported in studies in adults was suggested as a potential therapeutic target, but this threshold was not associated with improved outcomes. Additional studies to assess the utility of PbO2 monitoring after TBI in children are needed.

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Kristin J. Redmond, Simon S. Lo, Scott G. Soltys, Yoshiya Yamada, Igor J. Barani, Paul D. Brown, Eric L. Chang, Peter C. Gerszten, Samuel T. Chao, Robert J. Amdur, Antonio A. F. De Salles, Matthias Guckenberger, Bin S. Teh, Jason Sheehan, Charles R. Kersh, Michael G. Fehlings, Moon-Jun Sohn, Ung-Kyu Chang, Samuel Ryu, Iris C. Gibbs and Arjun Sahgal

OBJECTIVE

Although postoperative stereotactic body radiation therapy (SBRT) for spinal metastases is increasingly performed, few guidelines exist for this application. The purpose of this study is to develop consensus guidelines to promote safe and effective treatment for patients with spinal metastases.

METHODS

Fifteen radiation oncologists and 5 neurosurgeons, representing 19 centers in 4 countries and having a collective experience of more than 1300 postoperative spine SBRT cases, completed a 19-question survey about postoperative spine SBRT practice. Responses were defined as follows: 1) consensus: selected by ≥ 75% of respondents; 2) predominant: selected by 50% of respondents or more; and 3) controversial: no single response selected by a majority of respondents.

RESULTS

Consensus treatment indications included: radioresistant primary, 1–2 levels of adjacent disease, and previous radiation therapy. Contraindications included: involvement of more than 3 contiguous vertebral bodies, ASIA Grade A status (complete spinal cord injury without preservation of motor or sensory function), and postoperative Bilsky Grade 3 residual (cord compression without any CSF around the cord). For treatment planning, co-registration of the preoperative MRI and postoperative T1-weighted MRI (with or without gadolinium) and delineation of the cord on the T2-weighted MRI (and/or CT myelogram in cases of significant hardware artifact) were predominant. Consensus GTV (gross tumor volume) was the postoperative residual tumor based on MRI. Predominant CTV (clinical tumor volume) practice was to include the postoperative bed defined as the entire extent of preoperative tumor, the relevant anatomical compartment and any residual disease. Consensus was achieved with respect to not including the surgical hardware and incision in the CTV. PTV (planning tumor volume) expansion was controversial, ranging from 0 to 2 mm. The spinal cord avoidance structure was predominantly the true cord. Circumferential treatment of the epidural space and margin for paraspinal extension was controversial. Prescription doses and spinal cord tolerances based on clinical scenario, neurological compromise, and prior overlapping treatments were controversial, but reasonable ranges are presented. Fifty percent of those surveyed practiced an integrated boost to areas of residual tumor and density override for hardware within the beam path. Acceptable PTV coverage was controversial, but consensus was achieved with respect to compromising coverage to meet cord constraint and fractionation to improve coverage while meeting cord constraint.

CONCLUSIONS

The consensus by spinal radiosurgery experts suggests that postoperative SBRT is indicated for radioresistant primary lesions, disease confined to 1–2 vertebral levels, and/or prior overlapping radiotherapy. The GTV is the postoperative residual tumor, and the CTV is the postoperative bed defined as the entire extent of preoperative tumor and anatomical compartment plus residual disease. Hardware and scar do not need to be included in CTV. While predominant agreement was reached about treatment planning and definition of organs at risk, future investigation will be critical in better understanding areas of controversy, including whether circumferential treatment of the epidural space is necessary, management of paraspinal extension, and the optimal dose fractionation schedules.

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Jacob K. Greenberg, Donna B. Jeffe, Christopher R. Carpenter, Yan Yan, Jose A. Pineda, Angela Lumba-Brown, Martin S. Keller, Daniel Berger, Robert J. Bollo, Vijay M. Ravindra, Robert P. Naftel, Michael C. Dewan, Manish N. Shah, Erin C. Burns, Brent R. O’Neill, Todd C. Hankinson, William E. Whitehead, P. David Adelson, Mandeep S. Tamber, Patrick J. McDonald, Edward S. Ahn, William Titsworth, Alina N. West, Ross C. Brownson and David D. Limbrick Jr.

OBJECTIVE

There remains uncertainty regarding the appropriate level of care and need for repeating neuroimaging among children with mild traumatic brain injury (mTBI) complicated by intracranial injury (ICI). This study’s objective was to investigate physician practice patterns and decision-making processes for these patients in order to identify knowledge gaps and highlight avenues for future investigation.

METHODS

The authors surveyed residents, fellows, and attending physicians from the following pediatric specialties: emergency medicine; general surgery; neurosurgery; and critical care. Participants came from 10 institutions in the United States and an email list maintained by the Canadian Neurosurgical Society. The survey asked respondents to indicate management preferences for and experiences with children with mTBI complicated by ICI, focusing on an exemplar clinical vignette of a 7-year-old girl with a Glasgow Coma Scale score of 15 and a 5-mm subdural hematoma without midline shift after a fall down stairs.

RESULTS

The response rate was 52% (n = 536). Overall, 326 (61%) respondents indicated they would recommend ICU admission for the child in the vignette. However, only 62 (12%) agreed/strongly agreed that this child was at high risk of neurological decline. Half of respondents (45%; n = 243) indicated they would order a planned follow-up CT (29%; n = 155) or MRI scan (19%; n = 102), though only 64 (12%) agreed/strongly agreed that repeat neuroimaging would influence their management. Common factors that increased the likelihood of ICU admission included presence of a focal neurological deficit (95%; n = 508 endorsed), midline shift (90%; n = 480) or an epidural hematoma (88%; n = 471). However, 42% (n = 225) indicated they would admit all children with mTBI and ICI to the ICU. Notably, 27% (n = 143) of respondents indicated they had seen one or more children with mTBI and intracranial hemorrhage demonstrate a rapid neurological decline when admitted to a general ward in the last year, and 13% (n = 71) had witnessed this outcome at least twice in the past year.

CONCLUSIONS

Many physicians endorse ICU admission and repeat neuroimaging for pediatric mTBI with ICI, despite uncertainty regarding the clinical utility of those decisions. These results, combined with evidence that existing practice may provide insufficient monitoring to some high-risk children, emphasize the need for validated decision tools to aid the management of these patients.