Canal Structures Research Articles

Microstructural analysis of three‐dimensional canal network in the rabbit lumbar vertebral endplate

Insufficient nutrient supply through vertebral canal structures to the intervertebral disc (IVD) has been considered as an important contributor for disc degeneration. Despite previous canal structure characterization studies using histology, scanning electron microscopy, and angiography, among others, their three-dimensional (3D) topology inside the vertebral endplate remains poorly understood. This study aims to characterize the 3D canal structure in the rabbit lumbar vertebral endplate using micro computed tomography (μCT). Vertebral endplates were imaged using high-resolution μCT with 1.4 × 1.4 × 1.8 μm voxel size. Diameter, length, orientation, and depth starting from the vertebral endplate surface were analyzed for each canal using individual 3D canal models from the vertebral endplate scans. In the layer underneath the vertebral endplate, at a mean depth of 76.2 μm, longitudinally-oriented relatively short-length (57.6 μm) and small diameter (45.7 μm) canals were dominant. Large-scale canals with a mean diameter of 152.1 μm running parallel to the endplate surface were isolated at the depth of 224.1 μm. These canals were connected to both IVD and bone marrow spaces through vertically oriented canals.

Water pollution risk simulation and prediction in the main canal of the South-to-North Water Transfer Project

Summary The middle route of the South-to-North Water Transfer Project (MRP) will divert water to Beijing Tuancheng Lake from Taocha in the Danjiangkou reservoir located in the Hubei province of China. The MRP is composed of a long canal and complex hydraulic structures and will transfer water in open channel areas to provide drinking water for Beijing, Shijiazhuang and other cities under extremely strict water quality requirements. A large number of vehicular accidents, occurred on the many highway bridges across the main canal would cause significant water pollution in the main canal. To ensure that water quality is maintained during the diversion process, the effects of pollutants on water quality due to sudden pollution accidents were simulated and analyzed in this paper. The MIKE11 HD module was used to calculate the hydraulic characteristics of the 42-km Xishi-to-Beijuma River channel of the MRP. Six types of hydraulic structures, including inverted siphons, gates, highway bridges, culverts and tunnels, were included in this model. Based on the hydrodynamic model, the MIKE11 AD module, which is one-dimensional advection dispersion model, was built for TP, NH3-N, CODMn and F. The validated results showed that the computed values agreed well with the measured values. In accordance with transportation data across the Dianbei Highway Bridge, the effects of traffic accidents on the bridge on water quality were analyzed. Based on simulated scenarios with three discharge rates (ranged from 12 m3/s to 17 m3/s, 40 m3/s, and 60 m3/s) and three pollution loading concentration levels (5 t, 10 t and 20 t) when trucks spill their contents (i.e., phosphate fertilizer, cyanide, oil and chromium solution) into the channel, emergency measures were proposed. Reasonable solutions to ensure the water quality with regard to the various types of pollutants were proposed, including treating polluted water, maintaining materials, and personnel reserves.

Neurovascular disturbances after implant surgery.

With a steadily increasing impact of oral implant placement in daily practice, the number of reported surgical complications has also been growing. Recent studies reveal significant variation in the occurrence and morphology of neurovascular canal structures in the jaw bone. All those structures contain a neurovascular bundle, the diameter of which may be large enough to cause clinically significant damage. Therefore, it has become obvious that presurgical radiographic planning of jaw-bone surgery should pay attention to the neurovascular structures and their likely variations, in addition to examining many other factors, such as jaw-bone morphology and volume, bone trabecular structure and the absence of bone or tooth pathology. A critical review is accomplished to explore the potential risks for neurovascular complications after implant placement, with evidence derived from histologic, anatomic, clinical and radiologic studies. In this respect, cross-sectional imaging can often be advocated, as it is obvious that the inherent three-dimensional nature of jaw-bone anatomy may clearly benefit from a detailed spatial image analysis. Although this could initially be realized by conventional computed tomography, in current practice, dentomaxillofacial cone beam computed tomography might be used, as it offers high-quality images at low radiation dose levels and costs.

Cholangiocarcinoma of intrahepatic bile ducts with disseminated metastases in a Siamese cat: a case report

This case report concerns a four-year-old female Siamese cat which presented with inappetence, vomiting and weight loss. During routine clinical examinations of the patient, numerous neoplastic masses were detected in the liver, lungs and abdomen. Upon a request from the owner, the cat was euthanised. At necropsy, the primary tumour was detected in the liver. The tumour was greyish-white, firm, and multi-nodular. There were metastases in the portal lymph nodes, diaphragm, omentum, colon, caecum and lungs. Histologically, the tumour was characterised by a tubular pattern with periodic acid-Schiff- positive secretory material in glandular and canal structures. The neoplastic cells were positive to broad-spectrum cytokeratin. Histochemical and immunohistochemical stains were consistent with an intrahepatic bile duct carcinoma. This is the first case to report the metastasis of a cholangiocellular carcinoma to the colon in cats.

Lateral lingual vascular canals of the mandible: a CBCT study of 500 cases

The aim of the present study was to use cone-beam computed tomography (CBCT) images of patients to assess the localization, diameter, and course of the lateral lingual vascular canal (LLVC). CBCT (Morita, Accuitomo 170) images from 500 patients were used in the present study. The CBCT images were examined by two oral radiologists. The diameter, localization, and course of the LLVCs were assessed using axial, cross-sectional, and multiplanar reformatted images. Statistical analysis was performed using SPSS(®) v. 15 (SPSS Inc., Chicago, IL, USA), and t tests were used for statistical analysis. Of the 500 patients examined, 163 LLVCs were detected in 124 (24.8 %) cases. The mean diameter of LLVCs on the right side and left side was 0.65 ± 0.18 and 0.64 ± 0.17 mm, respectively. The majority of the LLVCs (n = 106, 83 %) were observed in the premolar region. There was a statistically significant difference between the occurrence of LLVCs in the premolar region and the other areas (p < 0.01). All the LLVCs observed in this study had a connection with inferior alveolar canal structures. The detection of an LLVC on CBCT images should alert the radiologist and surgeons to the possible presence of collateral arterial and vascular structures.

Evaluation of internal auditory canal structures in tinnitus of unknown origin.

ObjectivesThe aim of the present study was to evaluate the internal auditory canal (IAC) and the nerves inside it to define possible structural differences in cases with subjective tinnitus of unknown origin.MethodsCases applying to the ear, nose and throat department with the complaint of tinnitus with unknown origin and having normal physical examination and test results were included in the study (n=78). Patients admitted to the radiology clinic for routine cranial magnetic resonance imaging (MRI) and whose MRI findings revealed no pathologies were enrolled as the control group (n=79). Data for the control group were obtained from the radiology department and informed consent was obtained from all the patients. Diameters of the IAC and the nerves inside it were measured through enhanced images obtained by routine temporal bone MRIs in all cases. Statistical evaluations were performed using Student t-test and statistical significance was defined as P<0.05.ResultsMeasurements of IAC diameters revealed statistically significant differences between the controls and the tinnitus group (P<0.05). Regarding the diameters of the cochlear nerve, facial nerve, inferior vestibular nerve, superior vestibular nerve, and total vestibular nerve, no statistically significant difference was found between the controls and the tinnitus group.ConclusionNarrowed IAC has to be assessed as an etiological factor in cases with subjective tinnitus of unknown origin.

Microsurgical procedure combined with thoracoscopic resection for thoracic spinal canal dumbbell-shaped tumors

Background Spinal canal dumbbell-shaped tumor growing to spinal canal and paravertebral, may compress the spinal cord and invade the spinal canal, intervertebral foramen and spinal structures, and cause clinical symptoms. The dumbbell-shaped tumor in the thoracic vertebrae can penetrate thorax to cause pleural irritation symptoms, such as chest pain, short breath, cough and so on. As the microsurgical technique and video-assisted thoracoscopic surgery can remarkably reduce the harm, retrospective analysis was performed in order to explore the combined treatment of microsurgical proceduse and thoracoscopic resection for spinal canal dumbbell-shaped tumor and to summarize the surgical experience. Methods and Results There were 4 cases with thoracic spinal canal dumbbell-shaped tumors, among them 3 were typeⅡ and one was typeⅢ. In the surgery, 3 patients with typeⅡ underwent posterior mediastinal tumor resection under thoracoscope, and then underwent hemilaminectomy through posterior median approach. Under microscope, the tumors were entirely excised with excellent exporsure. The patient with type Ⅲ was firstly subjected to spinal canal tumor excision, and then entirely excisied intrathoracic tumor under thoracoscope. In 2 cases, the uncommon feelings became worse after surgery, but became better after half a year. In one case, the weakness of two legs, chest pain and cough were remarkably relieved, and in one case dry cough obliterated. During the follow-up period, there was no serious complication or death, and MRI revealed that the tumors were entirely excised without relapse. Conclusion The posterior median hemilaminectomy combined with video-assisted thoracoscopic surgery to treat spinal canal dumbbell-shaped tumors has following advantages: small trauma, few complication, good effectiveness and rapid recovery, which can be used as preferred treatment for spinal canal dumbbell-shaped tumor. doi：10.3969/j.issn.1672-6731.2013.12.004

Taphonomy of diploporite (Echinodermata) holdfasts from a Silurian hardground, southeastern Indiana, United States: palaeoecologic and stratigraphic significance

AbstractA microbioherm-bearing hardground within the middle Silurian (Wenlock) Massie Formation near Napoleon, southeastern Indiana, United States is encrusted by the attachment structures of numerous pelmatozoan echinoderms. Among the most common of these holdfasts are multi-plated discoidal structures representing the thecal attachments of diploporite ‘cystoids’. This large population of holdfasts permits the first detailed taphonomic and palaeoecologic study of hardground diploporite attachments, allowing for increased morphological understanding of these rarely studied structures and facilitating identification of holdfasts in deposits where they might have been overlooked or misidentified. The biostratinomic sequence commences with detachment of thecae, followed by weathering of isolated discoidal holdfasts to bring out radiating canal structures and plate sutures, eventually leading to removal of the interior floor to expose the underlying substrate. Continued exposure can result in separation of component holdfast plates, though cementation to the substrate prevents scattering of plates. Diagenetic precipitation of pyrite occurred after burial; the large size of crystals suggests late diagenesis, perhaps seeded by early diagenetic pyrite crystallites produced by decay of ligamentary tissue. Extrinsic taphonomic factors include overgrowth of holdfasts by laminar stenolaemate bryozoans and other echinoderm attachment structures. Diploporite holdfasts are not bored and are absent on microbioherms. Taphonomic data indicate the time-averaged nature of this hardground and its diploporite assemblage and permit prediction of similar occurrences at major flooding surfaces.

Spatial and temporal changes in groundwater salinity in South Florida

A combination of statistical and interpolation methods and Geographic Information System (GIS) spatial analysis was used to evaluate the spatial and temporal changes in groundwater Cl− concentrations in Collier and Lee Counties (southwestern Florida), and Miami-Dade and Broward Counties (southeastern Florida), since 1985. In southwestern Florida, the average Cl− concentrations in the shallow wells (0–43m) in Collier and Lee Counties increased from 132mgL−1 in 1985 to 230mgL−1 in 2000. The average Cl− concentrations in the deep wells (>43m) of southwestern Florida increased from 392mgL−1 in 1985 to 447mgL−1 in 2000. Results also indicated a positive correlation between the mean sea level and Cl− concentrations and between the mean sea level and groundwater levels for the shallow wells. Concentrations in the Biscayne Aquifer (southeastern Florida) were significantly higher than those of southwestern Florida. The average Cl− concentrations increased from 159mgL−1 in 1985 to 470mgL−1 in 2010 for the shallow wells (<33m) and from 1360mgL−1 in 1985 to 2050mgL−1 in 2010 for the deep wells (>33m). In the Biscayne Aquifer, wells showed a positive or negative correlation between mean sea level and Cl− concentrations according to their location with respect to the saltwater intrusion line. Wells located inland behind canal control structures and west of the saltwater intrusion line showed negative correlation values, whereas wells located east of the saltwater intrusion line showed positive values. Overall, the results indicated that since 1985, there was a potential decline in the available freshwater resources estimated at about 12–17% of the available drinking-quality groundwater of the southeastern study area located in the Biscayne Aquifer.

Rehabilitation and modernisation of irrigation schemes

Boosting agricultural productivity to increase food production and raise living standards is a policy in most developing countries as they face increasing populations, rising costs and deteriorating rural infrastructure. Many irrigation and drainage systems built over the last 100 years have suffered from a chronic lack of maintenance, resulting in canal networks that cannot deliver sufficient water. Crop yields and farmer incomes have thus fallen, exacerbating rural poverty. By this stage, deferred maintenance is not effective – comprehensive rehabilitation and modernisation is needed. This entails a hydraulic design review (possibly increasing capacity), improving water level control, water distribution and flow measurement by building new canal structures or modifying existing ones, lining canals as required and installing canal performance monitoring equipment. The author uses his experiences in Pakistan and Vietnam to discuss the different methods of water control used, the rehabilitation of canals and structures, lining criteria, monitoring equipment and cost estimates per hectare for rehabilitating and modernising gravity irrigation systems

A New Method of Locating the Optic Canal Based on Structures in Sella Region

The location of optic canal and the intracranial segment of optic nerve is difficult because of the high possibility of the deficiency of optic protuberance as well as its complex relationship to sphenoid and ethmoidal sinus. A new method of locating the optic canal and a comprehensive analysis of it and the structures around is of great importance. Our study aimed to provide a new method to locate the optic canal and analyze the relationship between optic canal and other structures in the sella region, which can be a guidance for endoscopic sinus surgery such as the optic nerve decompression and transsphenoidal approach to the pituitary adenoma and reduced complications caused by the injury of optic nerve. Computed tomography images of 120 sphenoid sinuses in adults were reviewed, and multiplanar reconstruction was used to make it possible to make the measurement in coronal, sagittal, and axial plane at the same time. The positional relationship between optic canal and the stationary structures in sella region was analyzed. The horizontal distance between the lowest point of sella bottom (SB) and sulcus prechiasmaticus in the sagittal plane was 8.08 (SD, 0.79) mm. The distance between the medial wall of optic canal and the midline of SB were 7.01 (SD, 1.43) mm in plane 1, 7.78 (SD, 0.86) mm in plane 2, 11.08 (SD, 0.82) mm in plane 3, and 13.81 (SD, 0.66) mm in plane 4; the angles between line BO and line BC were 87.99 (SD, 5.04) degrees in plane 1, 87.71 (SD, 4.98) degrees in plane 2, 82.54 (SD, 5.78) degrees in plane 3, and 82.57 (SD, 6.99) degrees in plane 4. As for the relationship between optic canal and the sphenoid sinus, there were 2.08% of sphenoid sinus of type A, 19.17% of type B, 45.00% of type C, 17.50% of type D, and 16.25% of type E. Optic canal can be located by the structures or markers in sella region such as the midline of SB, the lowest point of SB, the midpoint in the top edge of sphenoid sinus, and tubercular recess. The analysis of the relationship between optic canal and the sphenoid sinus as well as the data measured in our study is helpful to make an accurate location of the optic canal when the bony landmarks of optic canal are not available.

Occult Spinal Dysraphism in the Presence of Rare Cutaneous Stigma in a Neonate: Importance of Ultrasound and Magnetic Resonance Imaging

Occult spinal dysraphism is defined as a group of dystrophic conditions below an intact cover of dermis and epidermis. Ultrasonography using linear transducers is a fast, inexpensive, and effective method that makes it possible to view the content of the vertebral canal and bone structures. Magnetic resonance imaging (MRI) is reserved for elucidating the type of dysraphism and for planning corrective surgery. We present a case of a five-day-old female neonate who presented cutaneous stigmas (in the lumbar region, hands, and feet), in whom ultrasonography demonstrated dysraphism in the lumbar region. MRI confirmed the type of dysraphism and enabled surgical planning.

Utility of Transesophageal Echocardiography in Confirmation of Spread of Local Anesthetic in the Epidural Space

ABSTRACTA 30-years-old female with diagnosis of carcinoid tumor of right bronchus was planned to undergo right pneumonectomy under combined epidural and general anesthesia. A pediatric transesophageal echocardiography (TEE) probe was inserted for intraoperative monitoring of the right ventricular function. It also showed spinal canal structures (dura matter, epidural and subarachnoid space and spinal cord) and helped in visualization of local anesthetic spread in the epidural space.How to cite this articleKumar B, Goswami V, Rana SS, Puri GD. Utility of Transesophageal Echocardiography in Confirmation of Spread of Local Anesthetic in the Epidural Space. J Perioper Echocardiogr 2013;1(2):72-74.

Numerical study on the effect of frost heave prevention with different canal lining structures in seasonally frozen ground regions

Frost heave damage problems in canal linings are a common phenomenon in seasonally frozen ground regions. These problems are regarded as interactions between heat transport and moisture flow processes. To research the influence of frost heave prevention in two types of canal structures in the Ningxia irrigation district of China, a two-dimensional coupled heat transport and moisture flow model was used to analyze temperature characteristics in the traditional canal lining structure and a new type of canal lining structure for frost heave prevention. The simulated results from this numerical model are in agreement with in situ temperature measurements for both canal lining structures. The in situ measurement results show that the new canal lining structure exhibits low seepage, low thermal conductivity, quick drainage speed and less uneven deformation. Therefore, this new canal lining structure is a good choice for frost heave prevention in seasonally frozen ground regions.

Cochlear implantation in children with cochlear nerve deficiency: A report of nine cases

ObjectiveCochlear implantation for children with cochlear nerve deficiency remains controversial, as the presence of the cochlear nerve has been central to the success of cochlear implantation. This study sought to investigate whether there is any benefit from cochlear implantation for children with cochlear nerve deficiency. MethodsNine children with cochlear nerve deficiency and bilateral prelingual profound sensorineural hearing loss were included in this study. Inner ear and internal auditory canal structures were evaluated using magnetic resonance imaging and temporal bone computed tomography scans. Meaningful auditory integration scales, categories of auditory performance scores, speech intelligibility ratings and pure tone average threshold with cochlear implantation were measured for evaluation of hearing and speech performance. ResultsOnly four (44.4%) children had a significant improvement in pure tone average threshold with the cochlear implant device (77.5dBHL, 45dBHL, 51.3dBHL and 68.8dBHL). No child achieved sufficient speech intelligibility or perception ability during a follow-up of at least one year after surgery. ConclusionsThe decision to perform cochlear implantation in children with cochlear nerve deficiency must be undertaken with caution as it has limited effectiveness and uncertain cost-benefit.

Radiographic examination of patients with dehiscence of semicircular canals with digital volume tomography

Digital volume tomography (DVT) is an extension of panoramic tomography. With this diagnostic technique, characterized by high resolution, a narrow section width (0.125 mm), and three-dimensional display, small pathological processes can be well visualized. We examined 434 patients with DVT (Accu-I-tomo, Morita, Japan). Eleven patients with a history of peripheral vertigo presented a fistula of the labyrinth. The results were compared with intraoperative findings to evaluate the diagnostic value of DVT in cases of erosion of the semicircular canals. With high resolution and artifact-free demonstration of the labyrinth and inner ear structures, it was possible to determine the presence of a fistula of the semicircular canals in all 11 patients. An erosion of the lateral semicircular canal was found in nine patients with additional fistulae of the superior and posterior semicircular canals in one patient, a dehiscence of bone of the superior semicircular canal in one patient, and a dehiscence of the posterior semicircular canal in another patient. The predicted erosion of semicircular canals was verified in all patients during surgery where a closure of the fistulae was performed. DVT is an excellent technique to examine the semicircular canal structures in patients with peripheral vertigo, and expand the application of diagnostic possibilities in the lateral skull base. With this method, the preoperative diagnosis is improved allowing more accurate planning of the surgical procedure. DVT delivers a small radiation dose with a high resolution and a low purchase price for the equipment.

An unusual cause of dyspareunia

Pancreatic pseudocyst is a complication of acute pancreatitis and it usually manifests with abdominal pain. We report the case of a 45-year-old man with a history of acute pancreatitis who presented with abdominal pain, dyspareunia, and a palpable inguinal mass. Computed tomography scan revealed a large loculated pseudocyst that dissected through the pelvic cavity towards the inguinal canal, compressing pelvic and inguinal structures. When a patient with a history of pancreatitis develops an inguinal mass, a dissecting pancreatic pseudocyst should be suspected.

Anatomic Variations of Neural Canal Structures of the Mandible Observed by 3-Tesla Magnetic Resonance Imaging

Anatomical variations of the dental canal structures are present in a small proportion of the population and often go undiagnosed. In such cases, there could be an increased risk of complications during surgery and failure of anesthesia. The aim of this study was to search for anatomical anomalies in a relatively large random population by using 3-T high-field magnetic resonance imaging (MRI). Sixty-four dentate patients were examined using a modified T2 space sequence. The scans were analyzed with respect to anatomical features, variations, and rarities of the mandibular canal, mental canal, incisive canal, and the nutrient canals. Sixteen anatomical variations were identified in the study, and some of those images are presented. High-resolution MRI performed on a 3.0-T system can effectively visualize variations of the inferior alveolar nerve in dentate mandible of patients. Thus, MRI can be used in dentistry and oral surgery in vague or unclear cases, which could not be clarified by orthopantomography or even a computed tomographic scan, to improve patient care.

Evaluation of reliability and reproducibility of linear measurements of cone-beam-computed tomography

it was to evaluate intra- and interexaminer reliability and reproducibility of linear measurements in cone-beam tomography (CBCT) images. CBCT scans were obtained from 50 patients of a private clinic. Two examiners located the landmarks twice in two-dimensional and three-dimensional images on different days, with images performed 1 week apart. Intra- and interexaminer reproducibility and reliability were analyzed. the measurement error (ME) did not show significant differences between intra- and interexaminers. The intraclass correlations (ICC) between the intra- and interexaminer readings obtained with the different methods showed almost perfect matches. The results demonstrated high examiner reproducibility for linear and volumetric parameters with high intraclass correlation coefficient (ICC) and coefficient of variation (CV). The ICC showed that the methodology was highly reliable and reproducible (ICC- >0.99 and CV <1.5%). the measurements demonstrated strong agreement between examiners and significant reliability and reproducibility. Therefore, this methodology can serve as a standard for linear measurement analysis of the topography of mandibular canal and osseous adjacent structures.

Incarcerated femoral hernia in men: Incidence, diagnosis, and surgical management

Incarcerated femoral hernia in men: Incidence, diagnosis, and surgical management