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Results for “Anatomic Variation”

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PubMed2000

Importance of US findings in access planning during jugular vein hemodialysis catheter placements.

PURPOSE: To evaluate the significance of internal jugular vein ultrasound (US) findings in long-term hemodialysis patients and to assess how frequently these findings lead to a change in access approach. MATERIALS AND METHODS: One hundred consecutive hemodialysis catheter placements in 79 patients were retrospectively analyzed. Prior to catheter insertion, each patient underwent an US examination of the proposed access site by an interventional radiologist or interventional radiology fellow. The examinations were recorded on VHS tapes. The procedure notes, dictated radiology reports, and VHS tapes were reviewed for evidence of total occlusion, non-occlusive thrombus, presence of venous collaterals, stenosis, or variation in normal anatomy. The number of months that the patient required hemodialysis prior to catheter placement was also noted. RESULTS: Significant US findings were present in 28 patients (35%). Findings included total occlusion (n = 18), non-occlusive thrombus (n = 11), stenosis (n = 5), and anatomic variation (n = 1). These required a change in access approach in 21 patients. Unexpectedly, 54% of the patients with US findings had been undergoing dialysis for 12 months or less. CONCLUSION: These results underscore the importance of sonography in planning and performing vascular access procedures. A thorough US examination of the internal jugular veins is warranted prior to hemodialysis catheter placement, especially in patients with previous temporary or tunneled catheters. Three-quarters of patients with sonographic abnormalities required a change in access approach.

Catheterization, Central Venous↗

PubMed1996

Duplicated hepatic artery: radiologic and surgical implications.

Preoperative angiography of the coeliac trunk and superior mesenteric artery is routinely performed before liver resections and transplantations. For this purpose, it is usual to inject each branch of the coeliac trunk separately. Selective angiographic studies, however, may lead to overlooking surgically essential anatomic variations of the hepatic blood supply, as demonstrated by the present report. A case of a duplicated hepatic artery is presented, its radiologic and surgical implications discussed, and the relevant literature reviewed. This uncommon and particularly evocative feature illustrates the clinical importance of a sound knowledge of anatomical variants.

Adult↗

PubMed1997

Detection, visualization and animation of abnormal anatomic structure with a deformable probabilistic brain atlas based on random vector field transformations.

This paper describes the design, implementation and preliminary results of a technique for creating a comprehensive probabilistic atlas of the human brain based on high-dimensional vector field transformations. The goal of the atlas is to detect and quantify distributed patterns of deviation from normal anatomy, in a 3-D brain image from any given subject. The algorithm analyzes a reference population of normal scans and automatically generates color-coded probability maps of the anatomy of new subjects. Given a 3-D brain image of a new subject, the algorithm calculates a set of high-dimensional volumetric maps (with typically 384(2) x 256 x 3 approximately 10(8) degrees of freedom) elastically deforming this scan into structural correspondence with other scans, selected one by one from an anatomic image database. The family of volumetric warps thus constructed encodes statistical properties and directional biases of local anatomical variation throughout the architecture of the brain. A probability space of random transformations, based on the theory of anisotropic Gaussian random fields, is then developed to reflect the observed variability in stereotaxic space of the points whose correspondences are found by the warping algorithm. A complete system of 384(2) x 256 probability density functions is computed, yielding confidence limits in stereotaxic space for the location of every point represented in the 3-D image lattice of the new subject's brain. Color-coded probability maps are generated, densely defined throughout the anatomy of the new subject. These indicate locally the probability of each anatomic point being unusually situated, given the distributions of corresponding points in the scans of normal subjects. 3-D MRI and high-resolution cryosection volumes are analyzed from subjects with metastatic tumors and Alzheimer's disease. Gradual variations and continuous deformations of the underlying anatomy are simulated and their dynamic effects on regional probability maps are animated in video format (on the accompanying CD-ROM). Applications of the deformable probabilistic atlas include the transfer of multi-subject 3-D functional, vascular and histologic maps onto a single anatomic template, the mapping of 3-D atlases onto the scans of new subjects, and the rapid detection, quantification and mapping of local shape changes in 3-D medical images in disease and during normal or abnormal growth and development.

Anatomy, Cross-Sectional↗

PubMed2000

Bilateral mandibular accessory foramina and canals: a case report and review of the literature.

OBJECTIVES: To present a case of bilateral mandibular accessory canals and foramina observed on CT and review the relevant literature. RESULTS: Based on the literature, accessory canals and foramina are prevalent in the posterior mandible and the area of the symphysis and more frequently on the internal than the external surface of the mandible. Bilateral symmetry is common. Variations exist in size and number. Occurrence may change with age and racial origin. Nerves, neurovascular bundles, arterioles and venules have been found to occupy the accessory canals and foramina. No gender differences have been described. CONCLUSION: CT has advantages over two-dimensional radiography in identification of anatomical variations in the mandible.

Chronic Disease↗

PubMed1977

An anatomic-arthrographic study of the relationships of the lateral meniscus and the popliteus tendon.

The anatomy of the posterior lateral knee joint is studied through photography and radiography of plastic corrosion casts of the knee joint. The images thus obtained are compared to in vivo arthrograms. This anatomic-arthrographic correlation clearly demonstrates how the bursal extensions of the joint space about the popliteus tendon dictate the location and arthrographic appearance of the peripheral attachments of the posterior lateral meniscus. The casts also serve to illustrate a discussion of anatomic variation, embryology, and function of the popliteus apparatus. The largely unappreciated direct action of the popliteus muscle on the lateral meniscus is emphasized.

Cartilage, Articular↗

PubMed1992

Developmental toxicity of CI-921, an anilinoacridine antitumor agent.

CI-921, an anilinoacridine compound active against leukemic and solid tumors, was evaluated for potential developmental toxicity. Intravenous injections of CI-921 in dextrose were given to female Sprague-Dawley rats (0.1, 0.5, and 1.0 mg/kg) on Gestation Days (GD) 6-15 and to female New Zealand White rabbits (0.1, 1.0 and 2.0 mg/kg) on GD 6-18. Appropriate vehicle and untreated controls were included. Maternal and fetal parameters, including external, visceral, and skeletal malformations and variations, were assessed. Treatment of rats with 1.0 mg/kg resulted in maternal toxicity, manifested as reduced body weight gain and food consumption during and after treatment. Reduced fetal body weight, an increased incidence of stunted fetuses, malformations of the axial and appendicular skeleton, microphthalmia, and an increased number of anatomical variations (including anomalies of the axial skeleton and apparent hydronephrosis) also occurred in rats at 1.0 mg/kg. Treatment of rabbits resulted in no apparent maternal toxicity. However, reduced fetal body weight, agenesis of the azygous lobe of the lung, and an increased incidence of variations of the axial skeleton occurred at 2.0 mg/kg in rabbits. These results indicate that CI-921, at the highest dose tested in each species, produced developmental toxicity in the presence of maternal toxicity in rats, but in the absence of maternal toxicity in rabbits.

Abnormalities, Drug-Induced↗

PubMed2003

Morphology and dimensions of the mandibular jaw bone in the interforaminal region in patients requiring implants in the distal areas.

This study aimed to analyse variations in the mandibular interforaminal morphology in an attempt to identify potential risks or contraindications for surgery, especially implant installation, in this particular region. A total of 210 spiral computer tomography (CT) examinations of patients requiring endosseous implant installation in the lower jaw were re-evaluated to explore anatomical variations in bone morphology (shape and contour), and to measure parameters concerning height, width and inclination of the bone in the symphyseal atrea. All measurements were performed on the cross-sectional reformatted images mesial to the mental foramina. A lingual concavity (with a depth of 6 +/- 2.6 mm) was observed in 2.4% of the jaws, with a remaining bone height in that area ranging from 4.2 to 11.9 mm. A clearly lingual tilted/inclined morphology was seen in 28.1% of jaws with a mean angle of 67.6 +/- 6.5 degrees, but a relatively constant width (> 8.8 mm). The remaining jaws (69.5%) showed a slight broadening in the caudal direction. The morphologic parameters were influenced neither by age nor by gender. In conclusion, mandibles with a lingual concavity or a severe slope of the lingual cortex might confer increased risks of lingual perforations during trepanation surgery or graft harvesting as well as fenestrations during implant installation. The detection frequency of such variations within the lower jaw seems to advocate a profound dissection of the lingual site and, in the case of some special treatment strategies, additional cross-sectional radiography.

Adolescent↗

PubMed2002

Ulnar artery cannulation for coronary angiography and percutaneous coronary intervention: case reports and anatomic considerations.

Transradial artery cannulation is a useful alternative approach to the performance of diagnostic and interventional coronary procedures. However, its utility can be limited by incomplete palmar collateral support, access site failure, and anatomic variations. We report on five patients in whom percutaneous cannulation of the ulnar artery was primarily chosen, based on preprocedure examination, for coronary angiography in three patients and percutaneous coronary intervention in two others. The transulnar artery approach to coronary procedures is feasible and may be preferable in selected cases. Anatomic considerations are discussed.

Aged↗

PubMed1993

Variations of the ethmoid labyrinth and sphenoid sinus and CT imaging.

Three hundred macerated and partly isolated postmortem mid-facial bones were studied for the development, variations and dimensions of the structures of the nasal cavity. On 184 axial CT scans of bones (102 male, 82 female) from patients ranging in age from 1 to 90 years old, the dimensions of the ethmoid labyrinth and sphenoid sinus were studied in detail in order to determine which anatomic situation might be unsafe during clinical endoscopic interventions. Six anatomic variations were identified. Most unsafe for surgery seemed to be the following types: type III, in which the anterior diameter of the ethmoid labyrinth was large and the posterior ethmoid and sphenoid diameters were relatively narrow; type V, in which both ethmoid dimensions were large and the sphenoid diameter was narrow: type VI, in which the ethmoid labyrinth had an "hour-glass" shape. Present findings indicate that CT orientation before any endoscopic intervention might help to avoid serious complications.

Adolescent↗

PubMed1993

Management of the resected root end: a clinical review.

Careful management of the resected root end during endodontic surgery is critical to the overall success of the case. After resection, the root structure presents with multiple anatomical variations and considerations at both a macroscopic and microscopic level. These include root outline, canal anatomy, dentinal tubule configuration, presence of a smear layer and root canal filling material. Proper assessment of these variables will dictate the best methods for root-end management, along with the attainment of an anatomically compatible root face for optimal healing of the periradicular tissues.

Apicoectomy↗

PubMed1992

Comparison and investigation of bone mineral density in opposing femora by dual-energy X-ray absorptiometry.

A dual-energy X-ray absorptiometry (DXA) machine was used to measure the bone mineral density (BMD) of both femora in 760 female volunteers. Each volunteer completed a questionnaire and exclusion criteria were applied such that only 480 of these were considered normal subjects. The remaining 280 women failed to comply with the criteria and were considered 'abnormal'; their BMD results were analysed separately. Two abnormal subgroups, one with previous long bone fractures and one with radiologically diagnosed osteopenia, were studied. BMD values for femoral neck, Ward's triangle and trochanter were compared between the two femora in all the above groups. No dominance relationship was found when comparing left to right femur, averaged over any population studied, but large differences were found between the femora in individual volunteers. There was a high correlation between BMD in opposing femora of 0.91, 0.91 and 0.84 for the femoral neck, Ward's triangle and trochanter respectively. However, in normal subjects the percentage variation in these regions ranged up to 34%, 64% and 80% respectively at the different femoral sites. In addition, the normal population was divided into two subgroups, one in which the density difference between the femora was large, and the other in which the difference was statistically insignificant. The analytical and anatomical variations between these two groups were investigated. Only part of the difference appeared to be due to analytical problems and it seems that there is a genuine difference in femoral density. Poor correlation for femoral neck percentage density difference was found with average BMD, age, height and weight in the normal population.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗

PubMed2004

[The retro-orbicularis oculus fat (ROOF) or Charpy's fat pad. Descriptive and functional anatomy. Surgical concepts applied to the design of a frontotemporal lift procedure].

The eyebrow fat pad, or retro-orbicularis oculus fat (ROOF) is a syssarcosis, described as an anatomic and functional unity by M. Charpy in 1909. Our anatomic study on 12 (24 half-head) fresh cadaver specimens confirm anatomic variations, mainly according to age and sex. Synthesis of recent literature shows the renewed interest for this fat pad and its involvement in the eye's lateral flare. We will describe its detailed ultrastructure and the physiopathological mechanisms of aging, causing an earlier lateral eyebrow ptosis. So we can evolve new anatomic concepts applied to recent facial rejuvenative procedures, particularly frontotemporal facelifts (endoscopic or classical procedures), by a harmonious repositioning of the eyebrow and in order to restore the lateral flare of the eye.

Adipose Tissue↗

PubMed2006

A case of atypical insertion of the levator scapulae.

Anatomical variations in the musculature of the spine have the potential to cause functional and postural abnormalities, which in turn could lead to chronic myofascial and skeletal pain. We present a unilateral case of a 71-year-old Caucasian female in which the left levator scapulae muscle gave rise to an accessory head that inserted, by way of a flat aponeurotic band, to the ligamentum nuchae, the tendon of the rhomboideus major and the superior aspect of the serratus posterior superior muscle. The innervation was provided by a branch of the dorsal scapular nerve. By exerting unilateral traction on the vertebrae and surrounding musculature, this unusual variation might have resulted in clinical consequences including scoliosis and movement abnormalities of the head and neck as well as myofascial pain syndrome.

Aged↗

PubMed1995

The treatment of chronic sinusitis: a controversial issue.

The persistence of sinusitis after upper respiratory tract infection is influenced by a range of aetiological factors such as anatomical variation which may be surgically corrected, mucociliary abnormalities and immune deficiency. The latter is more common than previously realised, encompassing IgG subclass deficiency, reduced opsonization and Fc gamma receptor polymorphism. This has therapeutic implications, with the possibility of IgG replacement therapy and vaccination. CT scanning suggests that the age of the patient and anatomical abnormalities are important aetiological factors in chronic rhinosinusitis. Only when medical therapy fails, is surgery considered. Although a range of surgical procedures are available, an endoscopic approach may be directed at the ostiomeatal complex and is generally very conservative. Scanning is a prerequisite to this surgery, demonstrating both the extent of disease and the anatomy but requires careful interpretation. Furthermore, an endoscopic technique can be employed for a number of other sinus conditions though this should only be undertaken by an experienced surgeon. A long-term prospective study of children undergoing radical sinus surgery for neoplasia strongly suggests that concerns that surgery in the middle meatus might disturb subsequent facial development are unfounded.

Adolescent↗

PubMed2003

[Anatomical landmarks and surgical limits in the suboccipital transmeatal approach to the acoustic neuroma].

INTRODUCTION: To completely remove the intracanalicular portion of the acoustic neuroma through the retrosigmoid approach, we must open the posterior wall of the internal auditory canal (IAC). Therefore, drilling the IAC is one of the key steps we need to take in the transmeatal surgical approach. Nevertheless, there are no clear anatomical landmarks to identify structures such as the semicircular canals, the jugular bulb or air cells. The individual anatomical variations and those caused by the tumour itself make preoperative evaluation essential if we wish to avoid complications such as deafness, cerebrospinal fluid leakage, bleeding and air embolism. OBJECTIVE: We describe here the personal experience of the senior author (EU) in drilling the posterior wall of the IAC, with special reference to the anatomical landmarks and surgical limits in the suboccipital approach to the intracanalicular portion of the acoustic neuromas. MATERIAL AND METHODS: This work is based on anatomical data obtained from drilling human temporal bones obtained from cadavers, along with our experience with 20 patients who were operated on for acoustic neuroma using Samii's technique. RESULTS: We did not operate on any purely intracanalicular neurinomas using this approach. Two tumors were grade II (up to 20mm in diameter), 12 were grade III and 6 were grade IV. We did not drill far enough in any of these cases to be able to see the fundus of the IAC, which was confirmed by postoperative CT. Despite this, the tumor was considered to be completely removed in 17 cases. There was no mortality and we has no major complications as a result of drilling the IAC such as cerebrospinal fluid leakage or air embolism. we cannot guarantee that hearing loss of postoperative deafness, which were the norm except in one case of grade II, were caused by nervous, ischemic or labyrinthine lesions. CONCLUSION: In our material it was not possible to completely expose the IAC fundus using a retrosigmoid approach without injury to labyrinth. The areas in which the risk of secondary complications is greatest when drilling are the inferior wall and the IAC fundus. The medial extension of the suboccipital craniotomy makes drilling the intrameatal tumor exposure easier. There are no intraoperative landmarks to locate the petrous structures while drilling the IAC except for those provided by the surgeon's own experience.

Culture Techniques↗

PubMed1991

Diagnostic pitfalls in abdominal CT.

Many factors result in suboptimal performance of abdominal computed tomography (CT) or inaccurate interpretation of the images. Improper technique, observers' errors, and lack of clinical information are major contributors to misdiagnoses. Because of inadequate oral administration of contrast material, normal structures (eg, bowel) may remain unopacified and simulate tumors. Repeat scanning with additional contrast material and sodium bicarbonate, at selected levels, and perhaps with changes in patient position often reveals the true nature of pseudotumors in the gastrointestinal tract. Dynamic CT of the liver, performed during contrast material injection, yields the best results. Occasionally, reconstruction of axial images in coronal or sagittal planes helps delineate normal sectional anatomic variations of the diaphragm and liver and avoid misdiagnosis of pseudomasses. Volume averaging can cause problems when the section thicknesses are larger than the lesions (eg, small hepatic cysts) or structures are very close (eg, kidney and spleen); repeat CT with thinner sections is needed to obtain accurate attenuation values or delineate normal anatomic relationships. The gallbladder, spleen, and pancreas can change position due to prior surgery and raise suspicion of a mass unless clinical history is known. Familiarity with these and other pitfalls described herein should lead to accurate interpretation of CT scans.

Diagnostic Errors↗

PubMed2005

Variations of nerve roots of the brachial plexus.

OUTCOME: Aberrations observed during surgical treatments inspired us to initiate the investigation of variations in the formation of brachial plexus. MATERIAL AND METHODS: 100 brachial plexuses in 50 cadavers were examined for the incidence of neural variations. We examined the involvement of the C4 root and eventually of that of Th2 root, as well as various deviations in the exit of individual roots and their branches from the backbone. We have focused also on their paths, anastomoses, on their thickness or on their eventual absence. In addition to the anatomical complexity and variability, the specifics of motor innervation related to diagnostics are also emphasized. The attention is paid to the mechanisms and morphological reasons of the occurrence of specific types of injuries. RESULTS: Prefixed type was present in 24 cases (48 %), postfixed type was present just in one case. Aberrations have been observed in 14 cases (28 %). They occurred more frequently on the left side (9 cases) followed by two-sided aberrations (4 cases). CONCLUSION: This study enabled to identify and describe exceptional and hitherto undescribed anatomical variations in the formation of nerve roots of brachial plexus.

Brachial Plexus↗

PubMed2006

Detailed preoperative planning for fracture treatment with Ilizarov method in three dogs.

The purpose of this study is to present preoperative planning with consideration of the anatomical variations of different dog breeds, gross anatomy, preoperative radiographs and computed tomography (CT) images, ring number, ring type and ring levels, rod positions and rod number for fracture treatment using the Ilizarov method in three dogs. In all cases, preoperative radiographs of affected limb and contralateral limb, intact extremity's CT views and anatomical atlases were used for preoperative frame planning. The frame is assembled preoperatively, rehearsed and then it is applied. Preoperative radiographs and clinical findings of affected limbs are beneficial for preoperative frame planning, whilst CT views are not as they do not provide any different vision of anatomical structures for all cases. Other colleagues' and our anatomical atlases, including cross-sectional views of limbs, are satisfactory for preoperative planning. In addition, functional and cosmetical results in all three cases were determined to be very good.

Animals↗