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PubMed1997

Anatomical variation of human cancellous bone mechanical properties in vitro.

The aim of the study was to assess mechanical properties of human cancellous bone in vitro. Six hundred cubic specimens of cancellous bone were obtained from the tibia, femur, patella, lumbar spine and humerus of eight subjects. The elastic properties were assessed using an ultrasonic transmission technique developed and validated by Ashman (1). The results showed that differences exist between subjects significantly (p < 0.05) and that the mechanical properties vary along the length and the periphery (about a factor 3 to 5). Cancellous bone should be considered heterogeneous and as orthotropic materials exhibiting degrees of anisotropy varying from 2 to 4. Linear and power fit elationships for cancellous bone were found approximately equal. Powers vary from 1.3 to 1.7 for axial modulus versus density and 1.3 and 2.3 for strength versus density. Finally, these results suggest the use of appropriate mechanical properties upon the type of bone for finite element analysis.

Aged↗
PubMed1998

Magnetic Resonance Angiography in Pulsatile Tinnitus: The Role of Anatomical Variations.

Pulsatile tinnitus (PT) is a perception of a rhythmical sound that is synchronous with the heartbeats. Despite being seen rarely in daily practice, frequently it is associated with identifiable causes, thus warranting special attention in regard to the etiological diagnosis. PT results from blood flow turbulence, which in turn results from changes in flow velocity or in the vessel lumen. One of the most important causes of PT is the paraganglioma, a vascular tumor that appears as a reddish retrotympanic mass. However, a normal tympanic membrane mandates differentiating among other diagnoses, such as arteriovenous malformations or fistulas, intracranial or extracranial aneurysms, a high or dehiscent jugular bulb, and persistent stapedial artery. Owing to the progress of radiological evaluation, magnetic resonance angiography (MRA) has proven to be excellent for evaluating vascular diseases. From January 1995 to June 1997, the authors prospectively studied 16 patients with PT and normal otoscopic examination. The study comprised 1 male and 15 female patients (ages 25-71 years; mean age, 42.5 years). All were subjected to MRA evaluation, which revealed the etiological diagnosis in 13 cases (81.25%), including 2 aneurysms and 1 case of intracranial hypertension. Of the 13 patients 9(69.23%) presented with at least one variation of vascular anatomy of the skull, showing a close correlation, in most cases, with the side on which PT occurred. Our results confirm that MRA is an excellent primary screening modality for patients with PT and normal otoscopic findings. The authors point out the importance of making etiological diagnoses in such cases, suggesting that variations of the vascular anatomy of the skull are a possible etiology.

Journal Article↗
PubMed2000

[Surgical treatment of rare anatomic variations and anomalies of the thyroid gland].

Choristoma and thyroid gland malpositions are embryonal disorders. The aim of this article is ten years analysis of their diagnostic and operative treatment. In 1425 thyroidectomies we have found: one lingual, intratracheal, intracardial thyroid and ovarial struma; six separated intrathoracic goitre and 10 mostly intrathoracaly (80%) situated goitre; 1.4% out of all. Correct preoperative diagnosis we have in lingual thyroid, two intrathoracal thyroid and in all mostly intrathoracal thyroids, and in others after histopathological examination. Operative approach was: collar incision with medial sternotomy in nine, collar incision with lateral thoracotomy in three, right thoracotomy in two, and only collar incision in one. There were two operative complications, one recurrent nerve lesion and one mediastinal haematoma. There was no hypocalcaemia and mortality. Thyroid gland anomalies are very rare and associated with lot of problems in diagnostic and treatment. In specialised institutions frequency of operative complications is the same like in routine thyroid gland surgery.

Choristoma↗
PubMed1975

Fractures and anatomical variations of the proximal portion of the fifth metatarsal.

Fractures of the tuberosity of the fifth metatarsal are frequent and with conservative treatment uniformly heal well. In contrast, fractures of the metatarsal shaft distal to the tuberosity heal slowly. Of 100 fractures of the tuberosity, almost all were clinically united within three weeks and roentgenographically united within two months. Of twenty fractures in the proximal part of the shaft, five required bone grafts and the time elapsed before roentgenographic and clinical evidence of union was variable and often prolonged.

Adolescent↗
PubMed2000

[Stapedotomy and anatomical variations of the facial nerve].

Among the 595 stapedotomies performed between 1992 and 1999 (surgeon R. Häusler), there were 40 cases (6.7%) where the facial nerve had an abnormal course. In 32, a partial nerve prolapse over the oval window was noted with (6 cases, 1 being a duplicated nerve around the oval window) or without (26 cases) dehiscence in the long bony canal. In 8 cases, there was a total prolapse of the nerve over the oval window, with 2 special cases: facial nerve having an inferior course over the oval window and the promontory; facial nerve being widely spread over the oval window and the promontory. Concomitant anomalies of the stapes were seen and several patients had dysmorphic syndromes with conductive hearing loss since early childhood. Stapedotomy was performed in 39 patients. In the 32 cases of partial nerve prolapse, a small piston (0.4 mm) was placed in the lower part of the oval window which was sometimes enlarged towards the promontory, except when the nerve was duplicated: the prosthesis was placed into the footplate between the nerve branches. In the 8 patients with total facial nerve prolapse, the prosthesis was either placed directly in a burr hole into the promontory just below the oval window (6 cases), or, when the nerve ran over the promontory and over the oval window, the prosthesis was placed above the oval window at the site where the facial nerve is usually located (1 case). In the case where the nerve was spread widely over the oval window and the promontory, no prosthesis was placed. In the 39 patients where a stapedotomy was performed, the average hearing level gain ranged from -15 dB to 40 dB (average: 18 dB) at 0.5, 1, 2 and 4 kHz. The average residual air-bone gap was < 30 dB in 36 patients (92.3%), < 20 dB in 30 (77%) and < 10 dB in 16 (41%). A post-operative additional hearing loss > or = 10 dB occurred in 3 cases (10, 12.5 and 12.5 dB). There were no cases of post-operative deafness or facial palsy. This analysis shows that in many cases with an aberrant course of the facial nerve, stapedotomy using adequate and sometimes non-conventional techniques can give post-operative hearing improvement.

Adult↗
PubMedDate not supplied

Anatomical variations in the coronary arteries.

The following are observations on 500 consecutive cases of coronary angiographical studies carried out on patients without any case history of myocardial ishcemia. There were 251 males and 249 females. The patients' average age was 45 years old.

Adult↗
PubMed2001

Anatomical variations of gallbladder and biliary ducts among Ethiopians.

The extrahepatic biliary system was investigated to determine the types and frequency of variations in a group of Ethiopian subjects. A total of 110 specimens were obtained from adult Ethiopian subjects. Each specimen consisting of the whole of the liver, stomach, duodenum and the lesser omentum was removed and dissected carefully to expose the gallbladder and biliary ducts without disturbing their relationship. The majority (51%) of subjects had supramarginal type of gallbladder. The neck and infundibulum of the gallbladder were shorter in the present group compared to reports in other populations. There were significantly more cases of kinking of the gallbladder and Hartmann's pouch in the female than in the male subjects. However, there was no significant difference between the present and previously reported groups as well as the male and female subjects of the present group in the length or course of the cystic, hepatic or bile ducts. The findings in the present study suggest that variations in the gallbladder and the biliary ducts seen in the Ethiopian group are similar to what is reported in other populations. The significantly higher prevalence of kinking of the gallbladder and Hartmann's pouch in the female than in the male subjects may have some contribution to the higher rate of gallstone formation and biliary tract diseases in females.

Adult↗
PubMedDate not supplied

Implications of subtalar joint anatomic variation in calcaneal lengthening osteotomy.

The purpose of this study was to identify the percentage of individuals with distinct anterior and middle calcaneal facets. Calcaneal lengthening osteotomy, as popularized by Mosca, is extra-articular, with its site being the interval between the anterior and middle calcaneal facets. For individuals without a distinct anterior and middle facet, the subtalar joint must be violated to perform this operation. The authors studied 1,056 calcanei in 528 human cadavers from the Hamann-Todd Osteology Collection at the Cleveland Museum of Natural History. Findings were categorized using the Bunning and Barnett classification of subtalar facet configuration. Type A was found in 389 calcanei (37%), type B in 480 calcanei (46%), and type C in only two calcanei. Transitional type was found in 122 calcanei (12%). There was no anterior facet in 61 calcanei (6%). Asymmetry was found in 51 cadavers (10%). Most calcaneal lengthening osteotomies will occur intra-articularly, which may affect clinical results.

Adult↗
PubMed2002

[Anatomical variation of the helix root (Radicis Helicis)].

The root of the helix is not a smooth structure and morphologically constant but shows a series of irregularities, which are described in this article. 288 patients were aleatory studied and found some prominences, localized on the root of the helix. There are two tubercules--upper and lower--and one cleft or groove facing the lower branch of the antehelix. We report these variants as well as the prevalences dues to the age and sex.

Adolescent↗