Diagnostic approach, treatment, and outcomes of cervical sympathetic chain schwannomas: a global narrative review.

OBJECTIVE: This review examined the diagnostic approach, surgical treatment, and outcomes of cervical sympathetic chain schwannomas (CSCS) to guide clinical decision making. DATA SOURCES: Medline, EMBASE, and Cochrane databases. REVIEW METHODS: A literature review from 1998 to 2013 identified 156 articles of which 51 representing 89 CSCS cases were evaluated in detail. Demographic, clinical, and outcomes data were extracted by 2 independent reviewers with high interrater reliability (κ = .79). Cases were mostly international (82%), predominantly from Asia (50%) and Europe (27%). CONCLUSIONS: On average, patients were 42.6 years old (SD = 13.3) and had a neck mass ranging between 2 to 4 cm (52.7%) or >4 cm (43.2%). Nearly 70% of cases were asymptomatic at presentation. Presurgical diagnosis relied on CT (63.4%), MRI (59.8%), or both (19.5%), supplemented by cytology (33.7%), which was nearly always inconclusive (96.7%). US-treated cases were significantly more likely to receive presurgical MRI than internationally treated cases but less likely to have cytology (P < .05). Presurgical diagnosis was challenging, with only 11% confirmatory accuracy postsurgically. Irrespective of mass size, extracapsular resection (ie, complete resection with nerve sacrifice) was the most frequently (87.6%) performed surgical procedure. Common postsurgical adverse events included Horner's syndrome (91.1%), first bite syndrome (21.1%), or both (15.7%), with higher prevalence when mass size was >4 cm. Adverse events persisted in 82.3% of cases at an average 30.0 months (SD = 30.1) follow-up time. IMPLICATIONS FOR PRACTICE: Given the typical CSCS patient is young and asymptomatic and the likelihood of persistent morbidity is high with standard surgical approaches, less invasive treatment options warrant consideration.

An evaluation of the effectiveness of different techniques for intraoperative infiltration of antibiotics into alloplastic implants for use in facial reconstruction.

BACKGROUND: Reconstruction in the head and neck can be difficult owing to the size of the defect or characteristics of the tissue that needs to be replaced. Facial wounds or reconstruction sites can be subject to contamination, thereby risking infection of any implanted material even under ideal circumstances. Particular areas of concern are sites where minimizing the bacterial contamination prior to placing an implant is difficult (eg, the oral cavity and internal nose). Reconstruction involves the facial subcutaneous soft tissue and/or bone, and the ideal implant provides support and natural feel, as well as a low risk of infection. The biocompatibility of alloplastic implants depends on the tissue inertness of the implant and the porosity, allowing connective tissue ingrowth, which in turn decreases the susceptibility to infection. Scalafani et al demonstrated that alloplastic implants contaminated prior to fibrovascular ingrowth had a much higher incidence of infection and rejection. OBJECTIVE: To examine the effectiveness of several techniques for infiltrating antibiotics into alloplastic implants of different porosity using 2 commonly used alloplastic implants, expanded polytetrafluoroethylene (e-PTFE, or GORE-TEX) and porous high-density polyethylene (Medpor). RESULTS: Using an in vitro bacterial growth inhibition model, we found that suction infiltration of the implant with antibiotics was the most effective technique, with a statistically significant advantage over other techniques used. The advantages of the suction impregnation were seen to be most effective using alloplasts with a smaller pore size (20-30 microm) (P < .001), but there was a statistically significant difference even with implants with a larger pore size (150-200 microm) (P < .001). CONCLUSIONS: Suction infiltration of antibiotics into porous implants seems to be the most effective method identified using an in vitro testing protocol. Further experiments will be needed to confirm the effectiveness in reducing the perioperative risk of infection in vivo.

Seeing atoms with aberration-corrected sub-Angström electron microscopy.

High-resolution electron microscopy is able to provide atomic-level characterization of many materials in low-index orientations. To achieve the same level of characterization in more complex orientations requires that instrumental resolution be improved to values corresponding to the sub-Angström separations of atom positions projected into these orientations. Sub-Angström resolution in the high-resolution transmission electron microscope has been achieved in the last few years by software aberration correction, electron holography, and hardware aberration correction; the so-called "one-Angström barrier" has been left behind. Aberration correction of the objective lens currently allows atomic-resolution imaging at the sub-0.8A level and is advancing towards resolutions in the deep sub-Angström range (near 0.5A). At current resolution levels, images with sub-Rayleigh resolution require calibration in order to pinpoint atom positions correctly. As resolution levels approach the "sizes" of atoms, the atoms themselves will produce a limit to resolution, no matter how much the instrumental resolution is improved. By arranging imaging conditions suitably, each atom peak in the image can be narrower, so atoms are imaged smaller and may be resolved at finer separations.

Nodular fasciitis of the nasal cavity: a case report.

Nodular fasciitis is an uncommon tumor-like fibroblastic proliferation of the head and neck that is difficult to differentiate from its more malignant counterparts. Despite modern advances, making this distinction is challenging because the clinical presentation is nonspecific and the histologic and radiologic features are variable. Once nodular fasciitis is diagnosed, the primary treatment is conservative resection and observation. We describe a case of nodular fasciitis of the nasal cavity in a 43-year-old woman. To the best of our knowledge, this is only the second reported case of nodular fasciitis arising in the nasal cavity, and the first such case in an adult.

Early results from an aberration-corrected JEOL 2200FS STEM/TEM at Oak Ridge National Laboratory.

The resolution-limiting aberrations of round electromagnetic lenses can now be successfully overcome via the use of multipole element "aberration correctors." The installation and performance of a hexapole-based corrector (CEOS GmbH) integrated on the probe-forming side of a JEOL 2200FS FEG STEM/TEM is described. For the resolution of the microscope not to be severely compromised by its environment, a new, specially designed building at Oak Ridge National Laboratory has been built. The Advanced Microscopy Laboratory was designed with the goal of providing a suitable location for aberration-corrected electron microscopes. Construction methods and performance of the building are discussed in the context of the performance of the microscope. Initial performance of the microscope on relevant specimens and modifications made to eliminate resolution-limiting conditions are also discussed.

HRTEM imaging of atoms at sub-Angström resolution.

John Cowley and his group at Arizona State University pioneered the use of transmission electron microscopy for high-resolution imaging. Images were achieved three decades ago showing the crystal unit cell content at better than 4 A resolution. This achievement enabled researchers to pinpoint the positions of heavy atom columns within the unit cell. Lighter atoms appear as resolution is improved to sub-Angström levels. Currently, advanced microscopes can image the columns of the light atoms (carbon, oxygen, nitrogen) that are present in many complex structures, and even the lithium atoms present in some battery materials. Sub-Angström imaging, initially achieved by focal-series reconstruction of the specimen exit surface wave, will become commonplace for next-generation electron microscopes with C(S)-corrected lenses and monochromated electron beams. Resolution can be quantified in terms of peak separation and inter-peak minimum, but the limits imposed on the attainable resolution by the properties of the microscope specimen need to be considered. At extreme resolution the 'size' of atoms can mean that they will not be resolved even when spaced farther apart than the resolution of the microscope.

Use of image-guided systems in the reconstruction of the periorbital region.

The conflict in the Middle East has led to an increase in the incidence and severity of facial trauma evaluated at tertiary military medical facilities. The Naval Medical Center San Diego, San Diego, Calif, has treated 5 patients with penetrating injuries to the orbit with associated comminuted fractures. We have used the technology of image-guided surgery to assist in reconstructing these injuries. Image-guided surgery has many applications in the head and neck. This review consists of a series of traumatic applications of the image-guided system with a focus on orbital and midfacial trauma. We will discuss the benefits and drawbacks of this technique compared with previously described techniques.

Sub-angstrom atomic-resolution imaging from heavy atoms to light atoms.

John Cowley and his group at Arizona State University pioneered the use of transmission electron microscopy (TEM) for high-resolution imaging. Three decades ago they achieved images showing the crystal unit cell content at better than 4 angstroms resolution. Over the years, this achievement has inspired improvements in resolution that have enabled researchers to pinpoint the positions of heavy atom columns within the cell. More recently, this ability has been extended to light atoms as resolution has improved. Sub-angstrom resolution has enabled researchers to image the columns of light atoms (carbon, oxygen, and nitrogen) that are present in many complex structures. By using sub-angstrom focal-series reconstruction of the specimen exit surface wave to image columns of cobalt, oxygen, and lithium atoms in a transition metal oxide structure commonly used as positive electrodes in lithium rechargeable batteries, we show that the range of detectable light atoms extends to lithium. HRTEM at sub-angstrom resolution will provide the essential role of experimental verification for the emergent nanotech revolution. Our results foreshadow those to be expected from next-generation TEMs with CS-corrected lenses and monochromated electron beams.

Subacute hypoglossal nerve paresis with internal carotid artery dissection.

OBJECTIVES: To describe a case of an isolated hypoglossal nerve palsy in a patient with a spontaneous internal carotid artery dissection (ICAD). This condition is a well-recognized cause of cerebral ischemic stroke in patients younger than 45 years of age. Isolated cranial nerve neuropathy is a rare presentation. More common manifestations include incomplete hemiparesis, hemicrania, Horner syndrome, cervical bruit, pulsatile tinnitus, and multiple cranial nerve palsies. METHODS: A comprehensive literature search (Ovid, MEDLINE) for the presentation, diagnostic evaluation, treatment, and outcome of patients with internal carotid artery dissection was performed. RESULTS: A 43-year-old man presented with a 3-week history of mild dysarthria. There was no history of craniocervical trauma. The physical examination revealed an isolated left hypoglossal nerve paresis. Magnetic resonance imaging and angiography findings were consistent with a left skull base ICAD. The patient was successfully treated with anticoagulation therapy. The current rate of cranial nerve involvement is estimated at 10% of all ICADs. This is the second report of isolated hypoglossal nerve palsy without hemicrania in a case of atraumatic ICAD. CONCLUSIONS: Patients with an ICAD infrequently present to the otolaryngologist because of its head and neck manifestations. It is crucial to recognize atypical findings and to perform an accurate and prompt diagnostic evaluation. The foundation of treatment is aggressive anticoagulation, with surgical or radiologic intervention reserved for cases demonstrating life-threatening progression.

The effects of autologous platelet gel on wound healing.

Laser resurfacing techniques have become a popular means of achieving rejuvenation of damaged skin. Interest is great in attempting to speed re-epithelialization and healing so that patients can return to their normal activities as quickly as possible. Previous studies have demonstrated that wounds heal more quickly when they are covered and kept moist than when they are left open to the air. Until now, no study has been conducted to investigate whether the healing process of a superficial skin burn might be accelerated by the use of an autologous platelet gel as a biologic dressing. Our study of five pigs showed that autologous platelet gel can influence wound healing by stimulating an intense inflammatory process that leads to highly significant increases in the production of extracellular matrices and granulation tissue. The platelet gel accelerated vascular ingrowth, increased fibroblastic proliferation, and accelerated collagen production. However, the gel did not appear to accelerate re-epithelialization. The aggressive production of granulation tissue and the acceleration of collagen production might mean that autologous platelet gel will have a future role in the treatment of burns because the highly vascularized bed it helps create should promote the success of skin grafting in patients with deep partial-thickness and full-thickness burns.

Atomic resolution of lithium ions in LiCoO2.

LiCoO2 is the most common lithium storage material for lithium rechargeable batteries, used widely to power portable electronic devices such as laptop computers. Operation of lithium rechargeable batteries is dependent on reversible lithium insertion and extraction processes into and from the host materials of lithium storage. Ordering of lithium and vacancies has a profound effect on the physical properties of the host materials and the electrochemical performance of lithium batteries. However, probing lithium ions has been difficult when using traditional X-ray and neutron powder diffraction techniques due to lithium's relatively low scattering power when compared with those of oxygen and transition metals. In the work presented here, we have succeeded in simultaneously resolving columns of cobalt, oxygen and lithium atoms in layered LiCoO2 battery material, using experimental focal series of LiCoO2 images obtained at sub-ångstrom resolution in a mid-voltage transmission electron microscope. Lithium atoms are the smallest and lightest metal atoms, and scatter electrons only very weakly. We believe our observations of lithium to be the first by electron microscopy, and that they show promise for direct visualization of the ordering of lithium and vacancies in transition metal oxides.

Anticoagulation and spontaneous retropharyngeal hematoma.

A 57-year-old man treated with Coumadin for an episode of paroxysmal atrial fibrillation presented to the Emergency Department with progressive dysphagia and odynophagia. Physical examination revealed a large right-sided lateral and posterior pharyngeal wall mass. Laboratory studies were significant for an international normalized ratio (INR) of 5.4 with a white blood cell count of 11,600/muL and a hematocrit of 33.2%. A lateral soft tissue radiograph and computed tomography (CT) scan of the neck demonstrated a retropharyngeal hematoma compromising the airway. Rapid reversal of the coagulopathy was achieved with fresh frozen plasma and vitamin K. Patients with space-occupying retropharyngeal masses present a significant management dilemma. The choice between observation, intubation, or a surgical airway intervention must rely upon knowledge of the natural course and high rate of airway occlusion when faced with a patient who presents with a retropharyngeal hematoma. Once symptoms of airway compromise manifest, the airway must be expeditiously secured before complete obstruction occurs. This diagnosis should be sought when an anticoagulated patient presents with upper airway symptoms.

Atomic resolution three-dimensional electron diffraction microscopy.

We report the development of a novel form of diffraction-based 3D microscopy to overcome resolution barriers inherent in high-resolution electron microscopy and tomography. By combining coherent electron diffraction with the oversampling phasing method, we show that the 3D structure of a nanocrystal can be determined ab initio at a resolution of 1 A from 29 simulated noisy diffraction patterns. This new form of microscopy can be used to image the 3D structures of nanocrystals and noncrystalline samples, with resolution limited only by the quality of sample diffraction.

HRTEM image simulations for the study of ultrathin gate oxides.

We have performed high resolution transmission electron microscope (HRTEM) image simulations to qualitatively assess the visibility of various structural defects in ultrathin gate oxides of MOSFET devices, and to quantitatively examine the accuracy of HRTEM in performing gate oxide metrology. Structural models contained crystalline defects embedded in an amorphous 16-A-thick gate oxide. Simulated images were calculated for structures viewed in cross section. Defect visibility was assessed as a function of specimen thickness and defect morphology, composition, size, and orientation. Defect morphologies included asperities lying on the substrate surface, as well as "bridging" defects connecting the substrate to the gate electrode. Measurements of gate oxide thickness extracted from simulated images were compared to actual dimensions in the model structure to assess TEM accuracy for metrology. The effects of specimen tilt, specimen thickness, objective lens defocus, and coefficient of spherical aberration (Cs) on measurement accuracy were explored for nominal 10-A gate oxide thickness. Results from this work suggest that accurate metrology of ultrathin gate oxides (i.e., limited to several percent error) is feasible on a consistent basis only by using a Cs-corrected microscope. However, fundamental limitations remain for characterizing defects in gate oxides using HRTEM, even with the new generation of Cs-corrected microscopes.