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Christopher J Winfree

Publications and source records attributed to Christopher J Winfree.

10 recordsLinked to original sources
PubMed2005

Intraoperative positioning nerve injuries.

Intraoperative positioning nerve injuries are regrettable complications of surgery thought to arise from stretch and/or compression of vulnerable peripheral nerves. Generally thought to be preventable, these injuries still occur in patients despite rigorous preventative measures. Sometimes injuries, initially thought to be due to malpositioning, are caused by other factors, such as retraction injury or brachial plexitis. Because of the diversity of nerves susceptible to positioning injury, the clinician must be aware of a variety of presentations and must be able to distinguish them from other postoperative complaints. Prevention remains the mainstay of the management of positioning injuries. Diagnosed and managed appropriately, these lesions typically improve completely over time.

Anesthesia, General↗
PubMed2005

An extramedullary foramen magnum cavernous malformation presenting with acute subarachnoid hemorrhage: case report and literature review.

OBJECTIVE AND IMPORTANCE: This case summarizes our experience with the first described intradural extramedullary cavernous malformation at the foramen magnum and reminds the neurosurgical community to consider cavernous malformations in the differential diagnosis for subarachnoid hemorrhage. CLINICAL PRESENTATION: A 21-year-old man presented with an occipital headache, photophobia, nausea, neck stiffness, and fever of 10 days' duration. A lumbar puncture yielded a clear pink fluid with 300 leukocytes/mm3 (30% neutrophils and 65% lymphocytes) and 42,200 erythrocytes/mm3, a protein count of 243 mg/dl, and a glucose count of 56 mg/dl. Computed tomography revealed a 1.5-cm right-sided dural-based mass of high attenuation that spanned the foramen magnum and a segment of the upper spinal canal. Magnetic resonance imaging showed a loculated, heterogeneously enhancing mass with a cystic component that slightly displaced the medulla to the left. An angiogram was negative for aneurysms and vascular malformations but did show an area of early filling and slow washout of the epidural venous plexus at the posterior canal margin of C1 and C2. INTERVENTION: A suboccipital craniectomy and C1 laminectomy were performed. Upon opening of the dura, an encapsulated mass was visualized. The lesion was located on the right lateral surface of the cervicomedullary junction and was entirely extraparenchymal. The mass was microsurgically dissected, and its associated venous malformation was left intact. The patient's postoperative course was uneventful, with a return to baseline function. Pathological examination confirmed the diagnosis of cavernous malformation. CONCLUSION: Our report not only presents a unique combination of pathological lesion, location, and presentation but also demonstrates that such lesions may be treated surgically with excellent results.

Acute Disease↗
PubMed2004

Solitary cerebellar metastasis of malignant pleural mesothelioma: case report.

BACKGROUND: Malignant pleural mesothelioma is an uncommon malignancy that rarely metastasizes to the central nervous system and even less frequently occurs as a solitary lesion. CASE DESCRIPTION: We present a 71-year-old white female, nonsmoker, with no occupational exposure to asbestos. She presented with a 15-lb. weight loss over several months and persistent right subscapular pain radiating to her anterior chest. Imaging studies revealed a pleural mass, and biopsy confirmed fibrous type malignant pleural mesothelioma. During a metastatic workup, computed tomography (CT) and magnetic resonance imaging (MRI) of the head demonstrated a 1 cm subcortical, contrast-enhancing lesion without surrounding edema in the right posterior cerebellum. Surgical resection of the solitary cerebellar mass revealed fibrous-type metastatic malignant mesothelioma. Postoperatively, the patient received a combined chemotherapy regimen of Adriamycin and Cisplatin and underwent whole brain radiation therapy. CONCLUSIONS: We report the first resection of a solitary cerebellar metastasis of malignant pleural mesothelioma. We also review past cases of intracranial metastasis of this malignancy, its histologic subtypes, outcome, and recent treatment modalities.

Aged↗
PubMed2003

An improved functional neurological examination for use in nonhuman primate studies of focal reperfused cerebral ischemia.

There is renewed interest in primate models of acute stroke for the evaluation of potential therapeutic agents prior to clinical trials. The development of more precise functional outcome measures would improve the pre-clinical assessment of neuroprotective strategies. We have constructed a grading scale that utilizes an increased number of goal-oriented tasks to assess both behavior and motor function. The new scoring system is designed to enhance precision and accuracy when compared to existing scales. Twenty-seven male baboons were subjected to 1 h of middle cerebral artery territory occlusion followed by reperfusion. Outcome was evaluated using both a standard neurological function scale and a new task-oriented scale. Each scoring system was assessed for reproducibility (inter-observer reliability) and for association with radiographic infarct volume. The task-oriented grading system was significantly less variable than the standard outcome measure (p < 0.0001). The task-oriented neurological scale demonstrated stronger correlation with radiographic infarct volume (p < 0.0001) than the standard scale (p < 0.01) and more accurately reflected infarct size in animals with small strokes. Compared to the accepted system for grading neurological function, the task-oriented scale demonstrates improved inter-observer variability and a better association with radiographic outcome measures. Incorporating this refined neurological evaluation into a baboon model of stroke may serve to increase the functional predictive value of pre-clinical studies.

Animals↗
PubMed2003

Failure of intraoperative jugular bulb S-100B and neuron-specific enolase sampling to predict cognitive injury after carotid endarterectomy.

OBJECTIVE: Cognitive decline occurs in 25% of patients after carotid endarterectomy (CEA). Elevated serum concentrations of S-100B and neuron-specific enolase (NSE) occur after stroke, and serum S-100B levels at 24 hours are associated with clinical outcome after both stroke and CEA. We hypothesized that we could detect acute elevations in serum levels of these markers obtained intraoperatively from the jugular bulb (JB) and that these elevations would predict cognitive dysfunction postoperatively as measured by neuropsychometric test performance. METHODS: Forty-three patients scheduled for elective CEA were assessed with a battery of neuropsychometric tests before and 1 day after surgery. Before the carotid artery was clamped, a 6-French Fogarty catheter was inserted into the facial vein and threaded 6 cm rostrally into the JB. Serum samples were withdrawn from this catheter and simultaneously from a radial arterial catheter (A-line) at three time points: before clamping, 15 minutes into clamping, and after unclamping the carotid artery. Concentrations between groups were compared by analysis of variance and paired t tests. RESULTS: Total deficit scores were significantly worse in 13 (30%) of the 43 patients 1 day after surgery. There was a trend toward elevations in JB concentrations of S-100B relative to A-line levels 15 minutes after cross-clamping (11% elevation, P = 0.079, paired t test). In addition, 15 minutes after clamping of the carotid artery, levels of S-100B from the JB were significantly elevated compared with levels at baseline (P = 0.040, one-way analysis of variance). No significant changes were found between any time point in levels of S-100B from the A-line blood or of NSE from either the JB or the A-line. Subtle cognitive decline after CEA was not correlated with intraoperative levels of S-100B or NSE, but there was a weak, statistically nonsignificant, association between a rise in 15-minute S-100B levels and cognitive injury that was not seen with JB samples. CONCLUSION: Although intraoperative levels of S-100B and NSE from the JB failed to predict cognitive injury, carotid cross-clamping, independent of injury, seems to be associated with early elevations in S-100B.

Aged↗
PubMed2002

A controlled prospective study of neuropsychological dysfunction following carotid endarterectomy.

BACKGROUND: Although subtle cognitive injury as revealed by neuropsychological testing occurs in a substantial number of patients following carotid endarterectomy (CEA), there is controversy about whether this finding is a result of the surgery or the anesthesia. OBJECTIVES: To examine the changes in neuropsychological test performance in patients following CEA vs a control group of patients older than 60 years following spine surgery, so as to determine whether neuropsychological dysfunction after CEA is a result of surgery or anesthesia. METHODS: Patients undergoing CEA (n = 80) and lumbar spine surgery (n = 25) were assessed with a battery of neuropsychological tests preoperatively and on postoperative days 1 and 30. The neuropsychological performance of patients in the control group was used to normalize performance for patients in the CEA group, by calculating z scores using the mean and SD of the change scores in the control group. Significant cognitive dysfunction was defined as performance that exceeded 2 SDs above the mean performance of patients in the control group. RESULTS: Postoperative days 1 and 30 total deficit scores were significantly worse in the CEA group compared with the controls. When individual test results were examined, the CEA group performed significantly worse than the controls on the Rey Complex Figure test and Halstead-Reitan Trails B on day 1, and on the Rey Complex Figure on day 30. Overall, cognitive dysfunction was seen in 22 patients (28%) in the CEA group on day 1 and in 11 (23%) of 48 patients on day 30. CONCLUSIONS: Subtle cognitive decline following CEA occurs and persists for at least several weeks after surgery. This decline was absent in a control group.

Aged↗
PubMed2002

Interhemispheric intracranial pressure gradients in nonhuman primate stroke.

BACKGROUND: Although the development of significant interhemispheric intracranial pressure (ICP) gradients in the setting of unilateral stroke remains controversial, no study to date has investigated the existence of these gradients in a controlled, reproducible, clinically relevant model. Therefore, we used a primate model of reperfused hemispheric stroke to better characterize the development of these gradients. METHODS: Bilateral intraparenchymal ICP was continuously monitored in 7 adult male baboons subjected to left hemisphere reperfused stroke. Interhemispheric ICP gradients were calculated for each baboon and plotted over time. Infarct volume was determined using T2-weighted magnetic resonance imaging (MRI) at sacrifice. RESULTS: A bimodal distribution of interhemispheric ICP gradients was observed in animals with >20% infarct volume (22.1% +/- 0.9; range 21-23%) versus < or = 15% infarct volume (6.6% +/- 2.7; range 1-15%). In animals with >20% infarct volume, interhemispheric gradients developed early and persisted throughout the monitoring period. At 12 hours postreperfusion, animals with large infarcts demonstrated a mean pressure gradient of 13.8 +/- 4.3 mm Hg, compared to a mean gradient of -2.6 +/- 1.1 mm Hg for animals with < or =15% infarct volume. The difference in pressure gradients was statistically significant at all time points from 4 to 12 hours postreperfusion (p < 0.01). CONCLUSIONS: These data suggest that, in nonhuman primates, infarcts of a size approaching 20% of the hemisphere may be associated with significant ICP gradients. With these larger infarcts, ipsilateral monitoring is required if regional cerebral perfusion pressure is to be accurately assessed.

Animals↗