Open cranium model for the study of cerebrovascular dynamics in intracranial hypertension.

BACKGROUND: Significant research has been devoted to developing noninvasive approaches to neuromonitoring. Clinical validation of such approaches is often limited, with minimal data available in the clinically relevant elevated ICP range. NEW METHOD: To allow ultrasound-guided placement of an intraventricular catheter and to perform simultaneous long-duration ICP and ultrasound recordings of cerebral blood flow, we developed a large unilateral craniectomy in a swine model. We also used a microprocessor-controlled actuator for intraventricular saline infusion to reliably and reversibly manipulate ICP according to pre-determined profiles. RESULTS: The model was reproducible, resulting in over 80 hours of high-fidelity, multi-parameter physiological waveform recordings in twelve animals, with ICP ranging from 2 to 78 mmHg. ICP elevations were reversible and reproducible according to two predetermined profiles: a stepwise elevation up to an ICP of 30-35 mmHg and return to normotension, and a clinically significant plateau wave. Finally, ICP was elevated to extreme levels of greater than 60 mmHg, simulating extreme clinical emergency. COMPARISON WITH EXISTING METHODS: Existing methods for ICP monitoring in large animals typically relied on burr-hole approaches for catheter placement. Accurate catheter placement can be difficult in pigs, given the thickness of their skull. Additionally, ultrasound is significantly attenuated by the skull. The open cranium model overcomes these limitations. CONCLUSIONS: The hemicraniectomy model allowed for verified placement of the intraventricular catheter, and reversible and reliable ICP manipulation over a wide range. The large dural window additionally allowed for long-duration recording of cerebral blood flow velocity from the middle cerebral artery.

Dynamic networks of cortico-muscular interactions in sleep and neurodegenerative disorders.

The brain plays central role in regulating physiological systems, including the skeleto-muscular and locomotor system. Studies of cortico-muscular coordination have primarily focused on associations between movement tasks and dynamics of specific brain waves. However, the brain-muscle functional networks of synchronous coordination among brain waves and muscle activity rhythms that underlie locomotor control remain unknown. Here we address the following fundamental questions: what are the structure and dynamics of cortico-muscular networks; whether specific brain waves are main network mediators in locomotor control; how the hierarchical network organization relates to distinct physiological states under autonomic regulation such as wake, sleep, sleep stages; and how network dynamics are altered with neurodegenerative disorders. We study the interactions between all physiologically relevant brain waves across cortical locations with distinct rhythms in leg and chin muscle activity in healthy and Parkinson's disease (PD) subjects. Utilizing Network Physiology framework and time delay stability approach, we find that 1) each physiological state is characterized by a unique network of cortico-muscular interactions with specific hierarchical organization and profile of links strength; 2) particular brain waves play role as main mediators in cortico-muscular interactions during each state; 3) PD leads to muscle-specific breakdown of cortico-muscular networks, altering the sleep-stage stratification pattern in network connectivity and links strength. In healthy subjects cortico-muscular networks exhibit a pronounced stratification with stronger links during wake and light sleep, and weaker links during REM and deep sleep. In contrast, network interactions reorganize in PD with decline in connectivity and links strength during wake and non-REM sleep, and increase during REM, leading to markedly different stratification with gradual decline in network links strength from wake to REM, light and deep sleep. Further, we find that wake and sleep stages are characterized by specific links strength profiles, which are altered with PD, indicating disruption in the synchronous activity and network communication among brain waves and muscle rhythms. Our findings demonstrate the presence of previously unrecognized functional networks and basic principles of brain control of locomotion, with potential clinical implications for novel network-based biomarkers for early detection of Parkinson's and neurodegenerative disorders, movement, and sleep disorders.

Intracranial Hypertension Following Gunshot Wound to the Torcula: Case Report and Literature Review.

BACKGROUND: Elevation of bone for the treatment of depressed skull fractures overlying venous sinuses is rarely required or performed. The neurosurgical literature only describes a handful of cases of surgical intervention in which the posterior two-thirds of the superior sagittal sinus was involved. Clinical course is variable, signs and symptoms suggest increased intracranial pressure, and all conservative measures should be exhausted before proceeding with the surgical route. CASE DESCRIPTION: A 27-year-old man presented with a self-inflicted gunshot wound to posterior head. On presentation, there were no neurologic complaints. On imaging, the bullet fragment was associated with a comminuted anteriorly displaced fracture over the torcula. Vessel imaging showed tapering of the superior sagittal sinus and transverse sinuses near the torcula, suggesting narrowing due to mass effect. The patient did not respond to initial conservative management and developed worsening diplopia and papilledema concerning for increased intracranial pressure. Occipital/suboccipital craniectomy was performed with elevation of depressed skull fracture, decompression of dural venous sinus, removal of bullet, and mesh cranioplasty. Repeat ophthalmology examination postoperatively showed improvement in optic disc edema and diplopia. CONSLUSIONS: This case confirms that the approach of surgical management of superior sagittal venous sinus injuries associated with skull fractures described in the literature also can be used successfully for injuries over the torcula if conservative management does not help alleviate the symptoms and results in good outcome. It was felt that delayed surgery also plays an important role, as it gives time for scar tissue to form, which may help to protect the sinus from injury during surgery.

Intraocular Silicone Oil Migration into the Ventricles Resembling Intraventricular Hemorrhage: Case Report and Review of the Literature.

BACKGROUND: Intracranial silicone migration is a rare complication of ocular silicone oil endotamponade and may resemble intraventricular hemorrhage. The etiology of the phenomenon is challenging to understand. CASE DESCRIPTION: In an effort to shed light on this phenomenon, we report a case of a 67-year-old woman with ocular silicone oil endotamponade on the left eye due to retinal detachment who presented with headache to the emergency department. The imaging work-up revealed intraventricular silicone oil migration. CONCLUSIONS: The literature is reviewed through the perspective of pathophysiology. The migration of intraocular silicone oil into the ventricular system provides both an important complication for clinicians to be aware of, as well as a paradigm reminding us that cerebrospinal fluid spaces may have more extensive communications with other body compartments than previously thought.

Concussion Care Practices and Utilization of Evidence-Based Guidelines in the Evaluation and Management of Concussion: A Survey of New England Emergency Departments.

Evidence-based clinical practice guidelines can facilitate proper evaluation and management of concussions in the emergency department (ED), often the initial and primary point of contact for concussion care. There is no universally adopted set of guidelines for concussion management, and extant evidence suggests that there may be variability in concussion care practices and limited application of clinical practice guidelines in the ED. This study surveyed EDs throughout New England to examine current practices of concussion care and utilization of evidence-based clinical practice guidelines in the evaluation and management of concussions. In 2013, a 32-item online survey was e-mailed to 149/168 EDs throughout New England (Connecticut, Rhode Island, Massachusetts, Vermont, New Hampshire, Maine). Respondents included senior administrators asked to report on their EDs use of clinical practice guidelines, neuroimaging decision-making, and discharge instructions for concussion management. Of the 72/78 respondents included, 35% reported absence of clinical practice guidelines, and 57% reported inconsistency in the type of guidelines used. Practitioner preference guided neuroimaging decision-making for 57%. Although 94% provided written discharge instructions, there was inconsistency in the recommended time frame for follow-up care (13% provided no specific time frame), the referral specialist to be seen (25% did not recommend any specialist), and return to activity instructions were inconsistent. There is much variability in concussion care practices and application of evidence-based clinical practice guidelines in the evaluation and management of concussions in New England EDs. Knowledge translational efforts will be critical to improve concussion management in the ED setting.

Resection of Primary Brachial Plexus Tumor via a Modified Supraclavicular Approach.

Benign peripheral nerve sheath tumors are generally considered curable lesions, and surgical resection is recommended as the primary line of treatment. When these tumors occur in the brachial plexus, they are most frequently accessed via the supraclavicular approach. Traditional descriptions of this approach have included either transection of sternocleidomastoid (SCM) muscle fibers or disarticulation of the clavicular head of the SCM muscle. This report presents a simple and easy-to-adapt modification of the supraclavicular approach that offers greater preservation of the SCM muscle. The modification primarily consists of the creation of an intramuscular window between the sternal and clavicular heads of the SCM via the splitting and dilation SCM muscle fibers. This technique minimizes the disruption of SCM muscle tissue compared with previous descriptions and may be associated with improved postoperative pain and return to function.

The effect of a neurocritical care service without a dedicated neuro-ICU on quality of care in intracerebral hemorrhage.

BACKGROUND: Introduction of neurocritical care services to dedicated neuro-ICUs is associated with improved quality of care. The impact of a neurocritical care service without a dedicated neuro-ICU has not been studied. METHODS: We retrospectively identified all patients admitted to our institution with intracerebral hemorrhage (ICH) in two 12-month periods: immediately before the arrival of the first neurointensivist ("before") and after the neurocritical care service was established ("after"). There was no nursing team, ICU housestaff/physician extender team, or physical unit dedicated to the care of patients with critical neurologic illness during either period. Using an uncontrolled before-after design, we compared clinical outcomes and performance on quality metrics between groups. RESULTS: We included 74 patients with primary supratentorial ICH. Mortality, length of stay (LOS), proportion of patients with modified Rankin Score 0-3, and destination on discharge did not differ between groups when adjusted for confounders. Time to first two consecutive systolic blood pressure (SBP) measurements <180 mmHg was shorter in the "after" cohort (mean 4.5 vs. 3.2 h, p = 0.001). Area under the curve measurement for change in SBP from baseline over the first 24 h after ED arrival demonstrated greater, sustained SBP reduction in the "after" cohort (mean -187.9 vs. -720.9, p = 0.04). A higher proportion of patients were fed without passing a dysphagia screen in the "before" group (45 vs. 0%, p < 0.001). CONCLUSIONS: Introduction of a neurocritical service without a neuro-ICU at our institution was associated with a trend toward longer ICU LOS and improvement in some key metrics of quality of care for patients with ICH.

Postpartum trifecta: simultaneous eclamptic intracerebral hemorrhage, PRES, and herniation due to intracranial hypotension.

BACKGROUND: In the postpartum patient, sudden depression of consciousness may be caused by a number of etiologies and can result in serious consequences. Rapid, accurate diagnosis allows for specific treatments that optimize outcome, but diagnosis can be challenging in this population. We present a case of postpartum herniation due to intracranial hypotension in a patient with eclampsia, posterior reversible encephalopathy syndrome (PRES), and intracerebral hemorrhage (ICH). METHODS: Case report. RESULTS: A 26-year-old woman developed headache on postpartum day (PD) 1 after cesarean section with epidural anesthesia. Over the next 3 days, she developed progressively worsening headache and hypertension. On PD 5, she had a generalized seizure, leading to endotracheal intubation, propofol infusion, and transfer to our institution. By PD 6, she opened her eyes to voice, followed commands, moved all extremities, and had briskly reactive 4 mm pupils. MRI showed L parasagittal ICH with minimal mass effect, edema consistent with PRES, and brain descent with obliteration of the basal cisterns and tonsillar herniation. Later on PD 6, after diuresis for pulmonary edema, she became unresponsive with a dilated and nonreactive left pupil. She was laid flat for transport to CT, with improvement in arousal and pupil reactivity within 5 min. Intravascular volume was repleted with normal saline and albumin, and she was placed in the Trendelenburg position. Over the subsequent 8 h, she developed a dilated and nonreactive left pupil whenever her head was raised to horizontal. Her head position was gradually successfully raised over 48 h without need for a lumbar epidural blood patch. She was discharged home on PD 13 with only mild left arm dysmetria. CONCLUSIONS: Intracranial hypotension may coexist with other potential causes of cerebral herniation in the postpartum period. Establishing this diagnosis is crucial because its treatment is opposite that of other causes of herniation.

Aggressive pediatric meningioma with soft tissue and lymph node metastases: a case report.

Metastatic meningioma is extremely rare, occurring in an estimated 0.1% of cases. We report a case of pediatric meningioma metastatic to cervical soft tissue and lymph nodes. An 8-year-old boy presented with headaches, dizziness, and involuntary eye flickering. Magnetic resonance imaging (MRI) revealed a 7.5-cm parasagittal, dural-based mass with venous sinus encasement. Therapeutic embolization was followed by bilateral craniotomy, achieving subtotal resection. Histopathologic examination revealed an atypical meningioma with regions of hypercellularity, small cell morphology, sheeting architecture, increased mitoses, and brain invasion. Surveillance MRI studies showed growth of residual tumor and enlarging cervical soft tissue masses with posterior triangle lymphadenopathy. Radiation and surgical resection were employed for the intracranial tumor burden; resection of the soft tissue masses revealed metastatic meningioma, with soft tissue infiltration and metastasis to 8 lymph nodes. This case demonstrates the aggressive biologic potential of pediatric meningiomas, with potential for distant spread via cerebrospinal fluid leakage and lymphatic invasion.

Training for fitness: reconsidering the 80-hour work week.

The medical literature is replete with articles about the Accreditation Council for Graduate Medical Education's 2003 resident duty hour restrictions. Most of these papers describe creative and thoughtful responses to the new system. However, others express concern that the "80-hour work week" could hamper continuity of care and educational activities. Nevertheless, if fatigue impairs resident learning and medical care quality, then work hour restrictions seem worthwhile. We add our voices to the critics' for additional reasons. Data support that fatigue occurs even with reasonable work schedules, and residents do not reliably use time off from work to rest. Regulated work schedules can interfere with adequate rehearsal of the physical and mental stamina required in certain specialties, yet patients have a right to expect their physicians to be trained in the particular demands of those specialties. Similarly, residents have a right to a realistic understanding of authentic clinical practice. Further, while self-sacrifice need not be routine, trainees should feel that occasional self-sacrifice is appropriate and acceptable for a physician. We reject uniform, arbitrary duty hour limits for all specialties. Rather, we propose that a subspecialty-based system can foster the development of the endurance, skills, and reasoning that patients and colleagues expect.

Ventral thoracic spinal cord herniation: frequently misdiagnosed entity.

STUDY DESIGN: Case report with review of the literature. OBJECTIVE: Symptomatic spinal cord herniation through ventral aspect of dura is frequently misdiagnosed because this condition is rare. The most frequent misdiagnosis was that of dorsal arachnoid cyst. The purpose of this article is to provide insight on clinical presentation, diagnosis, and surgical treatment of this entity. Results of our cases were compared with that of the reported literature. SUMMARY OF BACKGROUND DATA: Eighty-six cases reported in the literature were reviewed and data are presented in this article. METHODS: We had 3 patients diagnosed with spinal cord herniation through the ventral aspect of the dural sac. All 3 cases were misdiagnosed initially and later successfully operated. The dura was repaired primarily with suture in 1 case and with surgical graft in the other 2 cases. RESULTS: Reduction of spinal cord herniation reverses some of the signs and symptoms that have been present for years. Two of our patients had remarkable recovery in motor strength and bladder function. The third patient improved but remained with residual myelopathy. CONCLUSION: Ventral herniation of the thoracic spinal cord is a partially treatable cause of myelopathy, when recognized promptly and treated surgically. Recognizing this infrequent cause of myelopathy prevents misdiagnosis. Delay in diagnosis may impair recovery at a later date.

Magnetic resonance imaging characteristics of hyperacute hemorrhage in the brain and spine.

Five distinct stages have been defined for the magnetic resonance (MR) appearance of intraparenchymal hematomas in the brain: hyperacute, acute, early subacute, late subacute and chronic. Despite the extensive study of the evolution of hematomas there has been little attention given to the MR appearance of the posthemorrhagic state within the initial hours after the hemorrhage occurs. We discuss and illustrate the MR imaging characteristics of hyperacute hemorrhage. Five cases of hyperacute intraparenchymal hemorrhage, one intracranial subdural and one intraspinal lumbar epidural hemorrhage are presented.