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Biomedical subjects

A Prescher

Publications and source records attributed to A Prescher.

At least 73 records · Page 4Linked to original sources
PubMed1997

New anatomical description of the cavernous sinus surface and its significance in microsurgery.

The anatomical and surgical approach to the sella region is of special interest for microsurgeons involved in ear, nose, and throat surgery, neurosurgery, ophthalmology, maxillofacial surgery, and skull base surgery. We investigated the surface morphology of the cavernous sinus and the sella turcica in 48 adult and 2 neonate specimens. To simplify the morphometric recording, distances between anatomical landmarks were defined. In addition, three triangles-the preinfundibular, the parasellar, and the internal carotid artery triangle-are introduced. These triangles are defined in order to determine the location where cranial nerves III, IV, V, and VI penetrate the dura with respect to the anterior and posterior clinoid processes and the tuberculum and dorsum sellae. The triangles were found to be symmetrical, with identical bilateral measurements, and the entry points of the cranial nerves were found to be constant. In 17 cases (34%), we found a dehiscence of the sellar diaphragm, and in 15 cases (30%), rope-like adhesions at the pituitary stalk.

Journal Article↗
PubMed1996

Anatomo-experimental study for lace fixation of winged scapula in muscular dystrophy.

Winging of the scapula is one of the major features of the rare facio-scapulo-humeral muscular dystrophy. Several methods of retention and fixation of the scapulae have been published, but most have technical disadvantages or complications. A modified method of operative fixation of the scapula to the chest using three polyester laces is described with the results of cadaveric studies on the stability of this system. In order to determine the optimal region for the scapula fixation using polyester laces we performed pull-out tests on twenty cadaver scapulae. Four points of insertion in the inferior part of the scapula were tested. The lateral margin showed the best results with regard to the tensile strength and the morphology of the resulting fractures. The elongation of the laces was measured as well. Compared to scapulothoracic arthrodesis interscapulo-scapulocostal scapulopexy leads to greater preserved mobility between the scapula and the chest wall and conserves vital capacity.

Adolescent↗
PubMed1996

MRI of degenerative bone marrow lesions in experimental osteoarthritis of canine knee joints.

OBJECTIVE: The objective of this study was to determine the value of MRI in the detection of degenerative bone marrow abnormalities in an animal osteoarthritis model. DESIGN: In 10 dogs with experimentally induced unilateral osteoarthritis of the knee, MRI was performed using two-dimensional spin-echo (2D-SE) and three-dimensional gradient-echo (3D-GE) imaging. Contrast enhanced T1-weighted 2D-SE sequences were also obtained after injection of gadolinium-DTPA. The results were compared with the gross and histopathologic findings and with radiography. RESULTS: Histopathologic specimens revealed 21 osteosclerotic lesions and 5 intraosseous cysts. On 2D-SE images, 24 of 26 lesions were detected, while 21 of 26 lesions were identified on 2D-GE sequences. Radiography, including conventional tomography, demonstrated 9 of 26 lesions. Regardless of the sequence weighting, all osteosclerotic lesions appeared hypointense on MRI. Signal loss in bone sclerosis resulted primarily from the reduction of intact fat marrow, the increased bone density being of secondary importance. Quantitative signal analysis allowed approximate estimation of the grade of sclerosis. On postcontrast images, sclerotic bone remained hypointense, although significant but non-specific enhancement relative to the normal fat marrow was observed. The extent of contrast enhancement did not correlate with the grade of osteosclerosis. All five cysts were readily diagnosed by MRI. Cysts displayed either central or marginal contrast enhancement within their cavities. CONCLUSIONS: MRI provides a sensitive method for the diagnosis of osteoarthritic bone abnormalities, allowing their differentiation from most non-degenerative subarticular lesions.

Animals↗
PubMed1996

Bone cement penetration of the acetabulum in total hip replacement. An experimental study.

Cones of cement passing through, or below, the acetabulum may be seen after total hip replacement and are due either to iatrogenic perforation of the wall or to substantial bony defects. An experimental study was undertaken to establish which structures might be affected by these cones. In 20 cadaveric specimens, the acetabula were divided into 4 quadrants and, after the cement was set, the structures within the pelvis were dissected. In the antero-inferior quadrant the cement impinged on either the obturator nerve or vein, or the external iliac vein. Anterosuperiorly, these structures and the external iliac artery were impinged. In the posterior quadrants, the obturator muscle and nerve, and vessels, were affected, and inferiorly the external obturator muscle was also involved. The size of the cones depended on the bony depth of the acetabulum. Compared with screws, the cement can cause late complications through heat necrosis and continuous friction. The posterosuperior quadrant is the safest area to make holes for anchoring the cup.

Acetabulum↗
PubMed1996

[MRT of experimental liver abscesses: a comparison of a new blood pool contrast medium with gadolinium-DTPA in animal experiments].

PURPOSE: In an experimental pyogenic liver abscess model, the signal intensities were compared intraindividually and interindividually after the application of a new blood pool contrast agent, 24-gadolinium-DTPA (diethylenetriamine-pentaacetic acid) cascade polymer, and after the application of gadopentetate dimeglumine. METHODS: In 20 rabbits with experimentally induced liver abscesses, the relative signal intensities of the liver, abscess centre, abscess wall and portal vein were assessed before and between 30 seconds and 60 minutes after injection of a 25 mumol/kg dose of gadolinium polymer and of 100 mumol/kg of gadolinium-DTPA, respectively. Measurements were performed at 1.5 Tesla, using a head coil and a Flash-2-D sequence. RESULTS: The interindividual comparison (unpaired T-test, p < 0.05) yielded significant differences of the relative signal intensities of the abscess centre (at any time point after contrast-media application), abscess wall (between 15 and 60 minutes after contrast media application), and portal vein (between 30 seconds and 7.5 minutes after contrast media application). The interindividual comparison showed a significantly higher abscess centre-liver contrast (between 30 seconds and 12.5 minutes after contrast media application) and a significantly higher abscess wall-centre contrast (between two and 7.5 minutes after contrast media application) after the application of gadolinium polymer compared with gadopentetate dimeglumine. CONCLUSION: In this animal model, the higher abscess centre-liver contrast after the application of gadolinium polymer was the basis for a better and prolonged visibility of the abscesses, as compared with images acquired after injection of gadopentetate dimeglumine.

Animals↗
PubMed1996

Computed tomography of experimental liver abscesses using a new liposomal contrast agent.

RATIONALE AND OBJECTIVES: Evaluation of computed tomographic enhancement characteristics of a new liposomal contrast agent (liposomal iodixanol [LI]) in a pyogenic liver abscess model in 17 rabbits. METHODS: Eight to 14 days after abscess induction (Escherichia coli), density-time curves were calculated for regions of interest in liver, abscess wall and center, spleen, portal vein, abdominal aorta, inferior vena cava, and kidney. Images were obtained every minute between 1 and 10 minutes, every 5 minutes between 15 and 60 minutes, and 75 minutes after 200 mg/kg LI application (group A: 7 rabbits) and after 600 mg/kg iopentol application (group B: 10 rabbits), and 90, 105, and 120 minutes after LI. RESULTS: The abscess wall-liver contrast after LI lasted from 10 to more than 120 minutes with a maximum of 30 delta Hounsfield Units (HU) at 45 minutes. For iopentol, the abscess wall-liver contrast lasted from 2 to 7 minutes with a maximum of 8 delta HU at 5 minutes. The abscess wall-center contrast after LI lasted from 1 to more than 120 minutes with a maximum of 112 delta HU at 40 minutes. For iopentol, the abscess wall-center contrast lasted from 1 to 75 minutes with a maximum of 79 delta HU at 1 minute. The liver-portal vein contrast after LI lasted from 1 to more than 120 minutes with a maximum of 100 delta HU at 20 minutes. For iopentol, the liver-portal vein contrast lasted from 1 to 8 minutes with a maximum of 38 delta HU at 2 minutes. An abscess wall was detected in a higher percentage of the LI images (86% LI, 56% iopentol), and images in the LI group correlated better with histopathology. CONCLUSIONS: The diagnostic value of LI exceeds that of iopentol in terms of overall abscess contrast and duration of the diagnostic interval. The higher hepatic vessel contrast allows better abscess localization.

Animals↗
PubMed1995

The various shapes of the paries jugularis and the frequency of additional ducts in the fossa jugularis as further factors influencing the spread of pathological processes.

We investigated 100 skulls and found in 8 cases a dehiscence of the paries jugularis. In 7 cases this was on the left side and in 1 case on the right. Thickness of the paries jugularis was estimated by means of a diaphanoscopic technique. We classified data according to four degrees of diaphaneity: 0 (hardly translucent), 1 (translucent), 2 (brightly translucent) and 3 (nearly transparent). The frequencies of these degrees were: 0, 38 cases (19%); 1, 122 cases (61%); 2, 35 cases (17.5%); and 3, 5 cases (2.5%). In investigating the frequency of additional ducts in the paries jugularis, we distinguished between three types of solum tympani: type I, no additional canals (18 cases); type II, 1-10 additional canals (172 cases); and type III, more than 10 additional canals (10 cases).

Adult↗
PubMed1995

[The MRT of osteophytosis in experimental gonarthrosis].

PURPOSE: The value of MRI for the detection of knee osteophytosis was determined in an animal osteoarthritis model. METHODS: 10 dogs with experimentally induced unilateral osteoarthritis of the knee were investigated with MRI including 2-D-spin echo (SE) and 3-D-gradient echo (GE) imaging. The results were correlated with gross and histopathologic findings and with radiography. RESULTS: Osteophyte formation appeared early in the osteoarthritic process. Pathological analysis yielded 65 osteophytes. With 3-D-GE imaging, 91% of the osteophytes were detected, while 68% were visible on 2-D-SE images. With two-level radiography, 43% of the osteophytes were diagnosed. Additional use of tunnel view and conventional tomography increased the detection rate to 65%. Independent of the imaging technique, MRI revealed three different signal patterns of the osteophyte bone structure. Compared with the histologically evident fat marrow content and the grade of bone sclerosis, best agreement was achieved with 2-D-SE sequences. However, a discrepancy remained in 22%. A fibrocartilaginous layer at the osteophyte surface could be delineated especially on 3-D-GE images. CONCLUSIONS: MRI provides the highest standard in non-invasive diagnosis of osteophytes in the knee. 3-D-GE imaging in particular can demonstrate early and small osteophyte formation.

Animals↗
PubMed1995

Does the area of the glenoid cavity of the scapula show sexual dimorphism?

The area of the glenoid cavity was determined in 214 scapulae (114 male, 100 female). Mean values of 9.87 cm2 for the males and 7.18 cm2 for the females were found. Presentation of the values as a histogram showed a bimodal distribution indicating sexual dimorphism, which was confirmed by the Mann-Whitney-Wilcoxon test for unconnected samples. The area of the cavity can therefore be used for the sexing of a skeleton. With the described method 60% of males but only 36% of females can be graded unambiguously.

Anthropometry↗
PubMed1994

[MRI of the hyaline knee joint cartilages. Animal and clinical studies].

The value of MR imaging for the detection of hyaline cartilage lesions using 2-D spin-echo and 3-D gradient-echo imaging was evaluated in an animal experiment in 10 dogs and in a clinical study in 30 patients. MR imaging findings were compared with histopathological and arthroscopy findings, respectively. Using MRI neither grade I nor grade II hyaline cartilage lesions were detectable. In the animal experiments 77% of grade III lesions and all the grade IV lesions were seen. However, in the clinical study only about the half of grade III and IV lesions were detected. 3-D gradient-echo MR imaging was superior to 2-D spin-echo imaging (p < 0.001), while 3-D FLASH and 3-D FISP did not differ significantly in the detection rate (p < 0.34). 3-D gradient-echo MR imaging seems to be the best method for the delineation of high grade cartilage lesions. However, early stages of cartilage degeneration are invisible even with this imaging modality.

Adult↗
PubMed1993

Anatomical and radiological observations concerning ossification of the sacrotuberous ligament: is there a relation to spinal diffuse idiopathic skeletal hyperostosis (DISH)?

In a collection of 101 anatomical preparations of the human pelvis, ossification of the sacrotuberous ligament was found in 8 cases. In 7 of these, the ossification showed a characteristic intraligamentous morphology, with a broad-based origin at the ischial tuberosity and tapering off craniomedially. The length varied between 1.1 and 7.2 cm. The surface of the bone formations appeared fasciculated, except in one case which had a wax-like flowing bone formation lying upon the sacrotuberous ligament. Careful anatomical and radiological examination of the spine, the ulnae, the calcanei and the iliac crests in these 8 cases, revealed in only one case any findings (spurs at the olecranon) that could be attributed to extraspinal manifestations of diffuse idiopathic skeletal hyperostosis (DISH). Indeed, in no case were the most widely accepted diagnostic criteria of DISH, the spinal alterations, seen. We therefore suggest that ossification of the sacrotuberous ligament is an autonomous finding and not a good indicator of the presence of spinal DISH.

Adult↗
PubMed1993

Effect of upper tibial osteotomy on fibula movement and ankle joint motion.

Several techniques of upper tibial osteotomy in the treatment of unicompartmental osteoarthritis of the knee have been described. Osteotomy of the fibula is normally also carried out, or alternatively, dissection of the capsule of the proximal tibiofibular joint. There is concern, however, that this latter procedure may have an adverse effect on the mobility of the ankle joint and on fibula rotation. To investigate these suspected interactions we performed experimental studies in 14 cadaver legs. The vertical, lateral and rotational movements of the fibula were measured with the ankle in neutral (0 degrees) and maximal ankle dorsiflexion before and after performing an interligamental upper tibial osteotomy of a standardised valgus wedge. Maximal ankle dorsiflexion before the osteotomy produced external rotation of the fibula in most specimens, whereas after osteotomy this movement caused mainly internal rotation. In the neutral position of the ankle, upper tibial osteotomy lead to external rotation of the fibula. The upward movement of the fibula head after osteotomy was 0.64 cm on average. There was no measurable vertical motion of the fibula during ankle dorsiflexion either before nor after upper tibial osteotomy. Ankle dorsiflexion improved minimally after osteotomy. In conclusion, this study shows that upper tibial osteotomy with dissection of the capsule of the proximal tibiofibular joint has no adverse effect on movement of the fibula or of the ankle joint. In addition, unlike fibular osteotomy, this technique also has the advantage that the risk of common peroneal nerve injury is minimal.

Ankle Joint↗
PubMed1993

Anatomical observations of spurs of the tuber ischiadicum.

In a study of 101 human pelves, 8 pelves (only males) were found with ossification in the area of the ligamentum sacrotuberale. Seven of these showed a characteristic and similar morphology and could be considered to be periosteal exostoses. The term "spur of the tuber ischiadicum" is proposed for this manifestation. There was a single case of metaplastic ossification, possibly of traumatic origin. Hence, not all ossifications in the area of the ligamentum sacrotuberale can summarily be classified as a spur of the tuber ischiadicum; careful discrimination is essential in every case.

Calcinosis↗
PubMed1993

A special form of hyperostosis frontalis interna.

The article describes a very severe case of hyperostosis of the frontal bone and discusses its possible differential diagnosis. What makes this case special is the fact that the osseous changes include all 3 layers of the bone. Macroscopically the lesion resembles an osteoma as described by Burkhardt (1970) and v. Eiselsberg (1906). The histological examination lead to the final diagnosis of hyperostosis frontalis interna. One must note that there were certain effects caused by a metastasis of a lobular carcinoma of the breast which influenced the osseous changes from the outer surface. The rough, spicula-like structure in the centre of the frontal squama should be put down to tumour erosion. The peripheral areas of the hyperostosis, however, still exhibit the original smoother texture of the disease. The final diagnosis in this unusual and possibly unique case was an intense hyperostosis frontalis interna with secondary changes due to the metastases of a lobular carcinoma of the breast.

Aged↗