silicon and Cadaver

The present investigation was performed with the objective of developing a method to estimate how long a corpse had been immersed in water after death (the time since death). Accurate determination of the time elapsed since death may lead to identification of the place of drowning, and therefore, serves not only as a piece of information useful for determination of the cause of death but also leads to prompt identification of the body. The results showed that diatoms attached to the surface of dental enamel increased with prolongation of immersion time in water. Further, as the immersion time increased, the quantity of O, Si, Mg, K, Al, and S detected on the surface of dental enamel increased, while the quantity of the main dental components (Ca and P) that were detected gradually decreased. Based on these results, we calculated a regression formula to estimate the immersion time. Our method is considered to be a breakthrough technique for evaluating the time since death more objectively, compared to the conventional method of determination based on the degree of decomposition of the corpse.

Topics: Aluminum; Cadaver; Calcium; Dental Enamel; Diatoms; Drowning; Forensic Dentistry; Humans; Magnesium; Microscopy, Electron, Scanning; Oxygen; Phosphorus; Potassium; Regression Analysis; Seawater; Silicon; Sulfur; Time Factors

We describe and quantitatively assess minimally invasive keyhole retrosigmoid approaches targeted to the upper, middle, and lower cranial nerve (CN) complexes of the cerebellopontine angle (CPA).. Anatomic dissections were performed on 10 sides of 5 fixed, silicone-injected cadaver heads. Surgical views through various trajectories were assessed in endoscopic videos and 3-dimensional (3D) interactive virtual reality microscope views. Surgical freedom and angles of attack to the proximal and distal areas of CN complexes of the CPA were compared among upper and lower keyholes and conventional retrosigmoid craniotomy using neuronavigation.. Compared with keyholes, the conventional approach had superior surgical freedom to most areas except for the distal CN V, the root of CN VII, and the root of CN IX, where differences were not significant. The conventional retrosigmoid approach provided a larger horizontal angle of attack than either the upper or lower keyholes for all selected areas; however, the vertical angles of attack were not different. Splitting the petrosal fissure resulted in a significant increase in the vertical angle of attack to the root zones of CNs V and VII but not to the distal areas of these nerves or CN IX. Illustrative cases of endoscope-assisted keyhole retrosigmoid approaches for the treatment of trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia are presented.. Targeted keyhole retrosigmoid approaches require detailed understanding of the 3D anatomy of the CPA to create appropriate locations of corridors, including skin incisions and keyholes. Endoscope assistance complements the standard microsurgical technique by maximizing the visualization and identification of the delicate neurovascular structures.

Topics: Adult; Aged; Cadaver; Cerebellopontine Angle; Cranial Nerves; Craniotomy; Endoscopy; Female; Glossopharyngeal Nerve Diseases; Head; Hemifacial Spasm; Humans; Magnetic Resonance Imaging; Male; Microvascular Decompression Surgery; Silicon; Skull

a silicone material was evaluated as an intervertebral disc thermal phantom. Temperature mapping was performed during the intradiscal electrothermal therapy (IDET) procedure and compared with results from the cadaver studies.. to determine whether a silicone material can be used as an intervertebral disc thermal phantom for evaluating thermal distributions of intradiscal electrothermal therapies and for reducing the need for cadaver and animal studies.. studies mapping thermal profiles of intradiscal heating therapies have been performed in cadavers and animal models. These studies are expensive, require special facilities and institutional reviews, and are susceptible to intercadaver and/or interanimal variation. A search of published data yielded no proposed thermal phantoms of the intervertebral disc. METHODS.: The thermal conductivity of a silicone material was measured and compared with that of an intervertebral disc. Thermal distributions were mapped in the material during the IDET procedure and compared with the distributions seen in cadaver studies. Logarithmic regression was performed to predict temperatures at certain distances from the IDET catheter. Mapping and regression were also performed for a decompression catheter.. the thermal conductivity of the silicone material, 0.587 W/m · °C, was similar to that previously reported for the intervertebral disc, 0.595 W/m · °C. Thermal distributions during the IDET procedure were comparable with those seen in previous cadaver studies. Logarithmic regression analysis predicted temperatures greater than 42°C and 60°C at distances of 14.10 and 2.31 mm, respectively, for the IDET catheter. These distances were 12.98 and 3.30 mm, respectively, for the decompression catheter.. the silicone material has a thermal conductivity similar to that of intervertebral disc. Temperature distributions in the material during IDET treatment are similar to that seen in cadaver studies. The material provides an alternative to cadaver and animal studies when determining thermal distributions of intradiscal electrothermal therapies.

Topics: Animals; Cadaver; Electric Stimulation Therapy; Feasibility Studies; Hot Temperature; Humans; Intervertebral Disc; Intervertebral Disc Displacement; Low Back Pain; Phantoms, Imaging; Silicon; Thermal Conductivity

Surgery for medically intractable epilepsy secondary to unihemispheric pathology has evolved from more aggressive hemispherectomy to less aggressive variations of hemispherotomy. The authors propose a novel minimally invasive endoscopic hemispherotomy that should give results comparable to conventional open craniotomy and microsurgery.. Endoscopic transventricular hemispherotomy was performed in 5 silicon-injected cadaveric heads in the authors' minimally invasive neurosurgery laboratory. The lateral ventricle was accessed endoscopically through a frontal and occipital bur hole. White matter disconnections were performed to unroof the temporal horn and to disconnect the frontobasal region, corpus callosum, and fornix.. Using an endoscopic transventricular approach, all white matter disconnections were successfully performed in all 5 cadavers.. The authors have demonstrated the feasibility of endoscopic transventricular hemispherotomy in a cadaveric model. The technique is simple and could be useful in a subgroup of patients with parenchymal volume loss and ventriculomegaly.

Topics: Cadaver; Cerebral Cortex; Cerebral Veins; Corpus Callosum; Endoscopy; Epilepsy; Feasibility Studies; Hemispherectomy; Humans; Lateral Ventricles; Minimally Invasive Surgical Procedures; Pia Mater; Postoperative Complications; Silicon

To assess the effect of cochlear implant (CI) insertion depth and surgical technique on intracochlear trauma.. Twenty-one fresh human temporal bones were implanted with CI electrodes and underwent histologic processing and evaluation. Specimens were grouped into 3 categories: 1) soft implantation technique and standard electrode; 2) soft implantation technique and flexible prototype array; 3) forceful implantations and standard electrode. Based on the grading system (1 to 4), 2 numeric values were calculated indicating the overall severity of cochlear damage (trauma indices).. Mean trauma index values were 13.8, 36.3, and 59.2 for group 1, 2, and 3, respectively. Differences in cochlear trauma (trauma index) were nonsignificant between specimens in groups 1 and 2 but were significant between groups 1 and 3.. This study gives evidence that intracochlear trauma increases with deep insertions. Thus, in cases where cochlear integrity might be important, limited insertions should be achieved.

Topics: Alloys; Basilar Membrane; Cadaver; Cochlea; Cochlear Duct; Cochlear Implantation; Cochlear Implants; Humans; Intraoperative Complications; Iridium; Platinum; Pliability; Prosthesis Design; Scala Tympani; Silicon; Spiral Lamina; Stress, Mechanical; Surface Properties; Temporal Bone

Surgical approaches to ambient cistern lesions are complex. We investigated the microanatomy of the transtemporal-transchoroidal fissure approach to the ambient cistern with emphasis on exposure of the posterior cerebral artery.. Dissections were performed bilaterally in five silicone-injected cadaveric heads. Critical anatomic distances, specifically with reference to the P2 segment of posterior cerebral artery in relation to the inferior choroidal point and P2-P3 junction, were measured with digital calipers. Other landmarks (temporal lobe tip, points from the temporal base to the choroidal fissure) were included for quantitative analysis.. The transtemporal-transchoroidal fissure approach provided adequate exposure of the ambient cistern, minimized temporal lobe retraction, and allowed assessment of regional microanatomy. The mean distance from the temporal base to the choroidal fissure measured 18.09 mm (range, 16.9-21.9 mm). The distances from the choroidal fissure to P2 varied at the coronal plane of the inferior choroidal point (mean, 6.96 mm; range, 3.6-12.0 mm) and the P2-P3 junction (mean, 6.02 mm; range, 4.3-6.9 mm), respectively.. The transtemporal-transchoroidal fissure approach provides a corridor to the ambient cistern and P2-P3 junction while minimizing temporal lobe retraction and avoiding interruption of temporal lobe venous drainage. Because of widely variable vascular anatomy, access to posterior cerebral artery lesions using this approach requires preoperative imaging to identify the specific location of the P2-P3 junction.

Topics: Arachnoid; Cadaver; Choroid Plexus; Dissection; Humans; Medical Illustration; Microsurgery; Silicon; Subarachnoid Space; Temporal Lobe

The aim of the present study was to determine variability of aluminum (Al) accumulation in human arteries and to observe the relationship between Al and five other elements (Ca, Fe, Mg, P, and Si) in the arteries. The Al contents in the thoracic aorta, basilar, coronary, femoral, and radial arteries of 26 human subjects were estimated by an inductively coupled plasma-atomic emission spectrometer and compared quantitatively to five elements. Al was detected in 88% of the cases in both the femoral and radial arteries, 73% in the coronary artery, 58% in the aorta, and 31% in the basilar artery. The average Al content was highest in the femoral artery (48.3 +/- 15.0 microg/g dry weight) and lowest in the basilar artery (8.1 +/- 3.6 microg/g). The Al had positive correlations with P, Ca, or Mg in both the aorta and femoral artery, and with Ca or P in the basilar artery. In the coronary artery, a correlation was found between Al and Si. No relationships were found between Al and each of the five elements in the radial artery. From these results, Al varied widely among the five arteries and accumulated more in the femoral and radial arteries but less in the basilar artery. These accumulations of Al were positively correlated with Ca or P in several arteries, but not sufficiently to explain the accumulation of Al. Further investigations are required to understand the mechanism of the variability of Al accumulation in the arteries.

Topics: Aged; Aged, 80 and over; Aluminum; Aorta, Thoracic; Arteries; Basilar Artery; Cadaver; Calcium; Coronary Vessels; Female; Femoral Artery; Humans; Iron; Magnesium; Male; Middle Aged; Phosphorus; Radial Artery; Silicon; Tissue Distribution

To study the microsurgical anatomy of intracranial segment of facial nerve so as to provide anatomic parameters for clinical operation.. Ten adult cadavers were fixed and perfused with color silicon. Facial nerves of these cadavers were observed and measured under operative microscope according to lateral cranial base operative approach. Ten dry skulls were dissected to observe the relationships of osseous structures. The anatomic relationship and data of different segment of facial nerve were obtained respectively.. The facial nerve was divided into five segments, namely, cerebellopontine angle segment, internal acoustic meatus segment, labyrinthine segment, tympanum segment and mastoid segment. The cerebellopontine angle segment and internal acoustic meatus segment paralleled the vestibulocochlear nerve. The labyrinthine aegment is the finest and shortest with the lebgth of 3.8 mm +/- 0.7 mm. The tympanum segment is closely related with osseous labyrinth. The mastoid segment, 15.5 mm +/- 1.9 mm long, leaves the cranium from stylomastoid foramen.. Facial nerve can be located with choroid plexus of the fourth ventricle in retrosigmoid approach. Arcuate eminence and greater superficial petrosal nerve are important mark to locate internal acoustic meatus segment and labyrinthine segment in antepetrosal approach. Tympanum segment may be exposed on the surface of petrous bone in some cases. The line between lateral semicircular canals and crista of digastric muscle is the mark of mastoid segment.

Topics: Adult; Cadaver; Facial Nerve; Humans; In Vitro Techniques; Perfusion; Silicon

Polarizing microscopy (PM), scanning electron microscopy (SEM), x-ray dispersive analysis (EDAX), x-ray diffraction (XRD), and infrared spectrometry (IR) were used to study the following pathological mineralizations: calcifications and silicon(Si)-bearing mineralizations in cerebral tissue from an epileptic child; traces of Si-bearing particles in periprosthesic mammarian tissue, and calcifications in capsular mammarian tissue from a patient with a silicone gel mammarian implant, and 2 calcium-bearing compounds, a typical apatitic calcification, and a nonphosphorous-bearing calcification in arterial tissues. In this tissue we also found Si-bearing particles due to an artifact from glassware.

Topics: Aged; Apatites; Arteries; Artifacts; Brain Diseases; Breast; Breast Diseases; Breast Implants; Cadaver; Calcinosis; Child; Electron Probe Microanalysis; Epilepsy; Female; Foreign Bodies; Glass; Humans; Lymph Nodes; Microscopy, Electron, Scanning; Microscopy, Polarization; Middle Aged; Prostheses and Implants; Silicon; Silicone Gels; Spectrophotometry, Infrared; Vascular Diseases; X-Ray Diffraction

A plethora of data has been used to condemn and defend the role of silicone and its association with "adjuvant disease." In the ongoing attempt to enhance our knowledge, we have chosen to identify tissue silicon levels (n = 15) in capsules that form around chemotherapeutic port-a-catheter devices, which consist of a metal dome encapsuled by silicone. We have compared these levels with previously established silicon levels in augmented breast capsules, distant tissue sites in these same augmented women, and nonaugmented cadaveric tissues from various geographic locations in the United States. All specimens were harvested by a "no touch" technique, not formalin fixed, frozen, and shipped to an independent toxicology laboratory for analysis. Inductively coupled plasma atomic emission spectroscopy was employed to obtain the tissue silicon measurements. Results demonstrated silicon values ranging from nondetectable in 9 patients to as high as 41 micrograms/gm. These values fell in between our cadaveric (0.5 to 6.8 micrograms/gm) and augmented tissue silicon levels (18 to 8700 micrograms/gm). Although the sample size is small and the power of statistical analysis is low, there was no correlation between the patient's silicon level and age, type of cancer, type of chemotherapeutic agent, radiation therapy, or length of time the port-a-catheters were in place. Although detectable levels of silicon identified around port-a-catheter devices were higher than expected, it is impossible to make any conclusions about these levels and the role of a potential collagen-vascular disease. What we have shown, however, is that silicone breast implants may not be the only medical device that can elevate tissue silicon levels. Our data seem to suggest that there may be a progression of measurable tissue silicon levels based on the amount of environmental or device-related silicon exposure a person has had at a particular time in his or her life. It is our belief that as we identify these tissue silicon levels, they will serve as a baseline and reference for further scientific studies.

Topics: Adolescent; Adult; Age Factors; Alloys; Breast; Breast Implants; Cadaver; Catheters, Indwelling; Child; Child, Preschool; Collagen Diseases; Connective Tissue; Equipment Design; Female; Humans; Infusion Pumps, Implantable; Male; Middle Aged; Neoplasms; Sample Size; Silicon; Silicones; Spectrum Analysis; Time Factors; Tissue Distribution; Vascular Diseases

A plethora of data has been used to condemn and defend the role of silicone and its association with "adjuvant disease." In the ongoing attempt to enhance our knowledge, we have chosen to identify tissue silicon levels in patients with saline implants or tissue expanders. We have compared these levels with tissue samples from a variety of patients with and without medicinal silicone devices from both the northeast and southwest United States over a 4-year period. All specimens were harvested by a "no touch" technique, non-formalin fixed, frozen, and shipped to an independent toxicology laboratory for analysis. Inductively coupled plasma atomic emission spectroscopy was used to obtain the tissue silicon measurements. Silicon tissue values in cadaveric tissue (n = 20 cadavers; n = 120 specimens) averaged 2.2 mcg/gm of tissue with undetectable silicon levels in over 50 percent of the specimens (range 0 to 45 mcg/gm; median = 0). Silicon levels surrounding port-a-catheter devices (n = 15 patients; n = 15 specimens) averaged 8.04 mcg/gm of tissue (range 0 to 41 mcg/gm; median = 0). Tissue levels in the capsules surrounding saline (n = 10 patients; n = 22 specimens) and silicone implants (n = 31 patients; n = 58 specimens) averaged 292 mcg/gm (range 0 to 1380 mcg/gm; median = 110) and 1439 mcg/gm (range 0 to 9800 mcg/gm, median = 490), respectively. Tissue levels, however, from distant sites (n = 22 specimens) in these same patients were equivalent to the cadaveric nonaugmented values (average = 3.2 mcg/gm; range 0 to 5.8 mcg/gm; median = 2.7). The results imply that there is a continuum of exposure to silicone medical devices based on the mechanical properties of silicone. The data seem to suggest that there may be a progression of measurable tissue silicon levels based on the amount of environmental or device-related silicone exposure a person has over his or her lifetime. It is our hope that these levels will serve as a baseline for our continuing knowledge of implantable medical devices.

Topics: Adjuvants, Immunologic; Adult; Aged; Autoimmune Diseases; Breast; Breast Implants; Cadaver; Catheters, Indwelling; Chemical Phenomena; Chemistry, Physical; Connective Tissue; Environmental Exposure; Equipment Failure; Female; Freezing; Humans; Longitudinal Studies; Male; Middle Aged; Prostheses and Implants; Silicon; Silicones; Sodium Chloride; Spectrum Analysis; Tissue Distribution; Tissue Expansion Devices; Tissue Fixation

Tissue silicon assays were performed on 10 nonaugmented cadavers and 25 augmented women to confirm our previous cadaveric data and to establish silicon levels at local and distant sites in augmented women undergoing explant and further reconstruction. All assays were performed by inductively coupled plasma atomic emissions spectroscopy (ICP-AES). Cadaveric tissues were sampled from six sites: liver, spleen, breast, nipple, axilla (soft tissue and nodes), and subcutaneous tissue (abdominal). Augmented women undergoing explant surgery had a portion of their implant capsule, breast tissue, and for those undergoing autogenous reconstruction, a portion of the autogenous donor site or distant tissue sampled. Twenty-four women had silicone implants; one had saline. Results revealed baseline silicon levels in all 10 non-augmented cadavers. These results were equivalent to our previous data, confirming the validity of these baseline data. Silicon tissue levels in the 25 augmented women revealed elevated levels within the implant capsule and surrounding breast tissue. However, silicon levels obtained from distant sites in augmented women were equivalent to the baseline nonaugmented cadaveric levels. There was no correlation between intact or ruptured implants and symptoms of collagen-vascular disease. In conclusion, study validates our original data of baseline silicon levels in nonaugmented cadavers. Contrary to what some may perceive as silicone floating throughout the body, we have found elevated levels around the implant only, and levels at distant tissue sites were equivalent to the baseline cadaveric data.

Topics: Abdomen; Adult; Aged; Aged, 80 and over; Axilla; Breast; Breast Implants; Cadaver; Female; Humans; Liver; Lymph Nodes; Male; Mammaplasty; Middle Aged; Nipples; Reproducibility of Results; Silicon; Skin; Spectrum Analysis; Spleen

Topics: Breast Implants; Cadaver; Capsules; Gels; Humans; Materials Testing; Silicon; Silicones; Tissue Distribution

Topics: Breast Implants; Cadaver; Humans; Silicon; Silicones; Tissue Distribution; Xenobiotics

Microscopic silicone in various tissues in the bodies of females with breast implants has led to the possible incrimination of these implants with connective-tissue disorders. Current technology precludes accurate silicone measurements, but all compounds containing the element silicon (which would include silicone) may be measured accurately. Direct positive correlations of silicon assays with silicone measured levels were confirmed by adding known amounts of silicone oil as a control. With the ubiquitous nature of organosilicons (food containers, syringes, etc.), we hypothesized that baseline silicon levels could be detected in tissues of cadavers without silicone breast augmentation. Ten cadavers were examined. Tissue samples were derived from subcutaneous fat, nipple, breast tissue, liver, spleen, and axillary nodes. Nine of 10 cadavers had silicon levels in various tissues. Measurements were performed by direct current atomic emission spectroscopy. The baseline data were compared with those from four augmented patients who underwent capsulectomies and implant removal. Silicon levels were fivefold higher in the augmented patients than in the nonaugmented cadavers. No difference in levels was noted if the patient had an intact or ruptured implant and/or was symptomatic versus asymptomatic for immunologic disease. This study was designed to measure baseline silicon levels in the normal population. It also has established an accurate level of measurement of tissue silicone.

Topics: Aged; Aged, 80 and over; Cadaver; Female; Humans; Male; Middle Aged; Prostheses and Implants; Reference Values; Silicon; Tissue Distribution

Topics: Cadaver; Catheterization; Drainage; Fluorocarbon Polymers; Humans; Kidney Transplantation; Silicon; Thoracic Duct; Transplantation, Homologous