Biomedical subjects

L P Müller

Publications and source records attributed to L P Müller.

At least 19 recordsLinked to original sources

PubMed2003

Rapid musculoskeletal magnetic resonance imaging using integrated parallel acquisition techniques (IPAT)--initial experiences.

PURPOSE: To investigate the feasibility of using multiple receiver coil elements for time saving integrated parallel imaging techniques (iPAT) in traumatic musculoskeletal disorders. MATERIAL AND METHODS: 6 patients with traumatic derangements of the knee, ankle and hip underwent MR imaging at 1.5 T. For signal detection of the knee and ankle, we used a 6-channel body array coil that was placed around the joints, for hip imaging two 4-channel body array coils and two elements of the spine array coil were combined for signal detection. All patients were investigated with a standard imaging protocol that mainly consisted of different turbo spin-echo sequences (PD-, T (2)-weighted TSE with and without fat suppression, STIR). All sequences were repeated with an integrated parallel acquisition technique (iPAT) using a modified sensitivity encoding (mSENSE) technique with an acceleration factor of 2. Overall image quality was subjectively assessed using a five-point scale as well as the ability for detection of pathologic findings. RESULTS: Regarding overall image quality, there were no significant differences between standard imaging and imaging using mSENSE. All pathologies (occult fracture, meniscal tear, torn and interpositioned Hoffa's cleft, cartilage damage) were detected by both techniques. iPAT led to a 48 % reduction of acquisition time compared with standard technique. Additionally, time savings with iPAT led to a decrease of pain-induced motion artifacts in two cases. CONCLUSION: In times of increasing cost pressure, iPAT using multiple coil elements seems to be an efficient and economic tool for fast musculoskeletal imaging with diagnostic performance comparable to conventional techniques.

Adolescent↗

PubMed2002

[The HEPFIEx simulator, a device for determination of friction between femur head prosthesis and cartilage].

We describe a device designed to investigate friction between various femoral head prostheses and human acetabula. It enables not only the determination of friction and the relevance of the play between the femoral head and acetabulum, but also the evaluation of the kinematic behaviour of bipolar prostheses. In the simulator, the various femoral head prostheses are placed on a special cone and tested against a human cadaveric acetabulum. The swiveling range of the device is uniaxial, and the swiveling angle is +/- 35 degrees. The maximum force produced pneumatically is 5kN. Testing of the simulator with a TEP was successful and friction-coefficients of < 0.1 were measured, as are reported in the literature.

Acetabulum↗

PubMed2001

Association of chronic lymphocytic leukemia with specific alleles of the HLA-DR4:DR53:DQ8 haplotype in German patients.

The etiology of chronic lymphocytic leukemia (CLL) remains unknown, though a genetic susceptibility has been suggested. Results of complete DNA typing of HLA alleles in CLL patients are lacking. We compared HLA class I and class II frequencies in 101 German CLL patients and 157 healthy German controls as determined by PCR-SSP/SSO DNA analysis and serologic typing. The most striking difference was the increased frequency of HLA-DRB4*0103 [relative risk (RR) = 2.74, p < 0.0025] among patients. The presence of alleles HLA-DRB1*0401, HLA-DQB1*0302 and HLA-DPB1*0301 as well as of homozygosity for HLA-DQB1 was also associated with a higher risk for CLL, though none of these differences remained significant after correction for multiple comparisons. No association was found for any HLA class I allele. Haplotype analysis revealed a CLL-specific linkage disequilibrium for HLA-DRB1*0401:DRB4*0103 and HLA-DRB4*0103:DQB1*0302. Our results suggest that CLL could be associated with distinct class II alleles of the Caucasian haplotype HLA-DR4:DR53:DQ8, which has also been related to a susceptibility for several auto-immune diseases. The positive, though weak, association of CLL with HLA-DPB1*0301 might represent an independent susceptibility factor since no linkage disequilibrium existed with any of the other CLL-associated alleles. None of the previously reported associations with HLA class I antigens was confirmed. Our results suggest that factors within or close to the human MHC class II region confer susceptibility to CLL.

Alleles↗

PubMed2001

Long-term results after operative treatment of femoral neck fractures with ceramic head prostheses.

From 1985-1990, a total of 277 elderly patients underwent hemiarthroplasty using a ceramic head prosthesis. Average patient age was 81.7 years. Of these, 77 patients were available for follow-up examination in 1993. A standardized score was calculated assessing activity, gait, and hip pain; the average score was 58 out of 78 possible points. Three patients had hip pain, and in 4 patients, radiographic examination revealed protrusio acetabuli. Two of 4 patients underwent revision surgery for replacement of the cup, leaving the stem in situ. Because of the small number of prosthetic-related complications, hemiarthroplasty using a ceramic head prosthesis is the recommended surgical treatment for femoral neck fractures in elderly patients. In the rare patient with protrusio acetabuli, revision surgery can be performed to replace the cup, leaving the stem in situ.

Acetabulum↗

PubMed2000

Frozen shoulder: a sympathetic dystrophy?

Diagnostic and clinical features of the frozen shoulder syndrome and the Sudeck syndrome are similar in many aspects. Radioisotope bone scan shows an increased uptake in affected areas in both diseases, while native radiographs show a progressive demineralisation. Measurement of bone mineral density (BMD) by quantitative digital radiography objectified these local decalcification processes in an early stage of the frozen shoulder syndrome; 10 of 12 patients with primary frozen shoulder had BMD decreases greater 21% in the humeral head of the affected shoulder compared to the non-affected side. In the immobilised control group with degenerative changes of the rotator cuff, calcifying tendinitis and shoulder instability (n = 12) and in the group of healthy probands (n = 20), the difference between the affected and non-affected side (left and right humerus of the healthy probands) was only more than 21% in one case each. There are several references in the literature that assume frozen shoulder to be an algoneurodystrophic process; our observations support this hypothesis, possibly leading to earlier diagnoses and extended therapeutic management.

Absorptiometry, Photon↗

PubMed2000

Endoscopic carpal tunnel release: results with special consideration to possible complications.

Single-portal endoscopic carpal tunnel release (Agee technique) was carried out in 148 patients. Of these, 100 were examined clinically and electrophysiologically 1 day before surgery and 1 and 3 months thereafter. Ten patients experienced transient ulnar neuropraxia and two patients complained postoperatively of intense pain in the middle and ring fingers. Three patients suffered residual symptoms. In one of these an incomplete release of the distal portion of the retinaculum flexorum was suspected and later confirmed by magnetic resonance imaging. Another patient had applied for pension due to problems associated with a vertebral fracture in addition to his carpal tunnel symptoms. A third patient with residual symptoms was rheumatic, and upon reexamination 6 months later he was virtually symptom free. Five of the 148 operations were converted to an open procedure due to poor visualization. A review of literature on carpal tunnel release (biportal Chow technique and uniportal Agee technique) uncovered 31 intra- and postoperative complications, including 14 affecting nerve structures, 2 tendon structures, 2 bony structures, and 9 the surrounding tissues. We discuss the most common complications, considering in particular the anatomical characteristics in the carpal tunnel region.

Carpal Tunnel Syndrome↗

PubMed2000

Is there still an indication for operative treatment of femoral neck fractures with a ceramic hemiprosthesis? Four-year results.

From 1985 to 1995, 417 patients with dislocated medial femoral neck fractures (Garden III-IV) were treated with hemiarthroplasty using a Biolox ceramic head. The average patient age at the time of operation was 81.5 years. A total of 140 survivors was available for follow-up examination with a mean prosthesis longevity of 55.8 months. The Harris hip score recorded a mean of 70.6 points. At the time of follow up, 5 patients had severe hip pain, and in 8 the roentgenographic examination revealed protrusio acetabuli. Five of these 8 patients underwent revision surgery for replacement of the cup, leaving the stem in situ.

Aged↗

PubMed2000

HLA-A, B, Cw and DRB1, DRB3/4/5, DQB1, DPB1 frequencies in German immunoglobulin A-deficient individuals.

HLA class I and II frequencies and haplotype frequencies were determined in 80 German immunoglobulin (Ig)A-deficient individuals and 157 healthy controls with normal IgA levels using serological and DNA typing methods. For several alleles, significant associations were found, which could be explained mainly in the context of a positive association with three different extended haplotypes (HLA-B*08:DRB1*0301: DQB1*0201, HLA-B*14:DRB1*0102:DQB1*0501 and HLA-B*44:DRB1*0701:DQB1*0202) and a negative association with a fourth haplotype (HLA-B*07:DRB1*1501:DQB1*0602). Furthermore, for the first time this study reports a positive association of IgA deficiency with DPB1 alleles. Homozygosity rate for the gene loci DRB1 and DQB1 was increased in IgA deficiency. Further analysis suggested a different pattern of HLA associations depending on the degree of IgA deficiency and the gender of the IgA-deficient individuals.

Alleles↗

PubMed1999

[Bilateral elastofibroma dorsi].

A 75-year-old man had painless, slowly enlarging tumors in the right and left infrascapular regions. Clinically, the tumors were nontender and semimobile. MR imaging and the operative exploration revealed tumors infiltrating the lateral thoracic muscles and periost of the scapula and underlying ribs. At surgery, the tumors were thought to be malignant, most likely liposarcomas. The histological examination showed the characteristic appearance of elastofibromas with spindle-shaped fibroblasts, which were separated by thick eosinophilic collagenous and elastic fibers. Elastofibromas are benign mesenchymal soft-tissue lesions that mainly affect elderly women. In 10 % of the patients bilateral, often asynchronous tumors are seen. Ninety-nine percent of the lesions are located in the subscapular region. Occasional elastofibromas have been described in the extremities, head, and in the abdominal and thoracic cavities.

Aged↗

PubMed1999

Pigmented villonodular synovitis of the shoulder: review and case report.

Pigmented villonodular synovitis (PVNS) as reviewed in detail elsewhere most frequently involves the knee and finger synovial structures; shoulder involvement is rare: A search through the English literature yielded 18 publications describing 25 cases of PVNS affecting the shoulder joint. Analyzing these reports we found the clinical and radiological findings generally to be nonspecific, often mimicking a malignancy, as in the case presented here of a 16-year-old boy with painful swelling in the area of the left proximal humerus. Magnetic resonance imaging showed a suspected malignant soft tissue mass involving the shoulder capsule and measuring 7.5 x 6 x 4 cm. Preoperatively the patient could recall no trauma; however, postoperatively he did report a distortion trauma of the affected shoulder following a bicycle accident. Intraoperatively, two tumors were found infiltrating the axillary vessels and nerve and tendon structures originating in the capsule of the shoulder joint. Rapid sections of the tissue revealed no signs of malignancy; further pathohistological examination revealed localized PVNS. Preoperatively, the shoulder joint was not suspected as the primary site of origin of the tumor because the patient had no complaints or functional deficits of the shoulder. The clinical presentation of such a PVNS lesion over the proximal humerus is unusual and to date has only twice been described in the literature.

Adolescent↗

PubMed1998

Radiation exposure to the hands and the thyroid of the surgeon during intramedullary nailing.

During 41 procedures of intramedullary nailing of femoral and tibial fractures, the primary surgeon and the first assistant wore ring dosimeters on their dominant index fingers. While the average fluoroscopy time per procedure was 4.6 min, the average dose of radiation to the dominant hand of the primary surgeon was 1.27 mSv and 1.19 mSv to the first assistant. The dose limit for the extremities is 500 mSv per year, as recommended by the International Commission on Radiological Protection. Extrapolation of the mean dose of the primary surgeon and first assistant per procedure of 1.23 mSv leads to the result that the recommended dose limit of 500 mSv would only be exceeded if more than 407 intramedullary nailing procedures are carried out per year. The duration of fluoroscopy time correlated with the radiation dose to the hands of the surgeons, though it was determined by phantom measurements that the majority of radiation exposure occurred during brief exposures of the hands in the direct X-ray beam on the X-ray tube near side of the patient. In order to assess the surface doses of the thyroid gland to the primary surgeon with and without a lead shield, we performed in vitro measurements during operative procedures of the lower leg simulating different intraoperative situations under fluoroscopic control. The average registered ionizing dosage without a thyroid shield was approximately 70 times higher than with thyroid lead protection. In a previous study we found average fluoroscopy times during intramedullary nailing of the tibia and femur of 4.6 min per procedure. Extrapolation of this value leads to the result, that even when 1000 intramedullary nailings were carried out without wearing lead protection, only 13 per cent of the dose limit recommended by the International Commission on Radiological Protection for the thyroid of 300 mSv per year would be reached; by wearing the lead protection only 0.2 per cent of the recommended dose would be reached.

Femoral Fractures↗

PubMed1998

[Pigmented villonodular synovitis of the shoulder joint].

A 16-year-old student presented with painful swelling over the left proximal humerus. Magnetic resonance imaging showed a malignant-looking soft tissue mass of 7.5 x 6 x 4 cm invading the shoulder capsule. The patient did not remember initially a shoulder trauma, through postoperatively he reported a distortion trauma of the affected shoulder after a mountain bike accident. Intraoperatively we found two tumors infiltrating the axillary vessel and nerve structures originating from the shoulder joint capsule. Quick examination of the tissue revealed to signs of malignancy, further pathohistologic examination showed a local pigmented villonodular synovitis. Unusual is the clinical presentation of the lesion over the proximal humerus, leading us preoperatively to neglect the possibility of tumor origin from the shoulder capsule, especially since the patient didn't have any complaints or functional deficits of the shoulder joint.

Adolescent↗

PubMed1998

Frozen shoulder--an algoneurodystrophic process?

The frozen shoulder syndrome and the Sudeck syndrome are clinically in many aspects similar. Radioisotope bone scan shows an increased uptake in the affected areas in both diseases, while standard radiographs show a progressive demineralization. With measurement of bone-mineral density by quantitative digital radiography these local decalcification processes were diagnosed in an early stage of the frozen shoulder syndrome: of 12 patients with primary frozen shoulder 10 had a bone-mineral density decrease of more than 21% in the humeral head of the affected shoulder compared to the unaffected side. In the control groups (n = 32) the difference between affected and unaffected side (left and right humerus of the healthy probands) was in only one case each above 21%. There are several indications in the literature assuming the frozen shoulder to be an algoneurodystrophic process. Our observation supports this hypothesis, and may possibly lead to earlier diagnosis and improved therapeutic management.

Bone Density↗

PubMed1997

[Effectiveness of lead thyroid shield for reducing roentgen ray exposure in trauma surgery interventions of the lower leg].

The occupational radiation exposure of trauma surgeons has increased over the last few years as a result of biologic orthopaedic procedures like intramedullary nailing as closed reduction and insertion of distal interlocking screws need fluoroscopic control. In order to assess the surface doses of the primary surgeon with and without lead shield of the thyroid we performed in vitro measurements during operative procedures of the lower extremities simulating different intraoperative situations under fluoroscopic control. The average registered ionizing dosage without thyroid shield was 70 times higher compared to the measurements with thyroid protection. In a previous study we found average fluoroscopy times during intramedullary nailing of tibia and femur of 4.6 min per procedure. Extrapolation of this value leads to the result, that even when 1000 intramedullary nailings were carried out without wearing lead protection, 13% of the dose limit recommended by the International Commission on Radiological Protection for the thyroid of 300 mSv per year would not be exceeded, whereas by wearing the lead protection only 0.2% of the recommended dose would be reached.

Body Burden↗

PubMed1997

[Paradoxical embolism after femoral fracture].

The foramen ovale is anatomically open in 25% of individuals, but functionally closed by the higher pressure in the left antrum. Right-to-left shunt and subsequent paradoxical embolism may occur when pressure in the left antrum rises, for example, as a result of pulmonary embolism. In the present case we demonstrate a patient who presented 20 days after osteosynthetic treatment of a femoral fracture with word-finding deficits. Cerebral MRT revealed a fresh ischemic insult. Duplex ultrasound of the legs showed a fresh thrombosis of the superficial femoral vein and scintigraphy of the lungs detected pulmonary embolism. Transesophageal contrast echocardiography trapped a hemodynamically spontaneous, open foramen ovale. Duplex ultrasound of the carotid arteries detected no pathological findings. Deep vein thrombosis and pulmonary embolism can be clinically inconspicuous and become manifest by cerebral deficits resulting from paradox embolism and cerebral ischemia.

Aged↗

PubMed1997

[Traumatic thrombosis of the distal ulnar artery (hypothenar hammer syndrome) in a golf player with an accessory muscle loop around Guyon's canal. Case report].

Arteriography of a 34-year-old golf player with M. Raynaud symptoms of his left hand revealed filling defects in the digital arteries II to IV fingers associated with corkscrew-like configuration of the ulnar artery in Guyon's space. The preoperative workup including 50 clinical laboratory tests searching for connective tissue diseases, vasculitis, and haematological disorders was without pathological findings; more central embolic sources were excluded angio- and cardiologically. MRI-scan demonstrated an anomalous muscle at the level of the hamate hook located underneath the M. palmaris brevis forming a sling around the ulnar artery. Surgery showed the ulnar artery distal to the anomalous muscle dilated with fibrotic thickening and intraluminal thrombosis. The involved A. ulnaris segment was resected and an interpositional vein graft performed. Histopathologic sections showed fibrosis of the arterial wall with intraluminal thrombosis and elastica fragmentation indicating traumatic genesis (hypothenar-hammer syndrome). We suspect intensive golf playing with the grip style and repetitive movements leading to pressure injury of the hypothenar area and the underlying ulnar artery. Contraction of the anomalous muscle belly may have additionally compressed the artery slowing down the arterial flow and accelerating the thrombosis.

Adult↗

PubMed1997

[Complications of endoscopic retinaculum dissection].

Reviewing the literature on endoscopic carpal tunnel release (biportal Chow-technique and uniportal Agee-technique), we found 31 different intra- and postoperative complications. Of these, 14 affected nerve structures, four vessel structures, two tendon structures, two bony structures, and nine surrounding tissues. The most common complications were analyzed taking anatomical and pathological variations of the carpal tunnel into consideration. In our own prospective series of 88 endoscopic releases of the carpal tunnel using the Agee technique, we had eleven complications: one patient suffered residual symptoms, five patients experienced transient ulnar neurapraxia, and one patient complained of intense pain in the middle- and ringfinger after the operation. In four cases, intraoperative change of technique from endoscopic to open became necessary, due to poor visualization.

Carpal Tunnel Syndrome↗

PubMed1996

Hypothenar hammer syndrome in sports.

Repetitive blunt trauma or single severe trauma to the hypothenar region may lead to traumatic thrombosis of the distal ulnar artery (hypothenar hammer syndrome, HHS). In the sports-related literature we found and analysed isolated cases attributed to injuries sustained during sporting activities such as baseball, badminton, handball, football, frisbee, softball, karate, weight-lifting and hockey. Further, we report the case of an amateur golf player with ischaemic symptoms of his left hand, where angiography revealed filling defects in the digital arteries associated with a corkscrew-like configuration of the distal ulnar artery. Magnetic resonance imaging (MRI) scan demonstrated, at the level of the hamulus ossis hamati, accessory fibres of m. palmaris brevis forming a sling around the ulnar artery. Treatment by resection of the thrombosed a. ulnaris segment and replacement with an autologous vein graft resulted in complete relief of symptoms. Histological sections revealed partially organized thrombi adherent to the intimal surface with fragmentation of the internal elastic membrane, indicating a traumatic genesis. As the mechanism of injury, we suspected intensive golf playing with the grip style and subsequent motions leading to pressure injury of the hypothenar area and the underlying ulnar artery. Contraction of the anomalous muscle belly may have additionally compressed the artery, slowing down the arterial flow and promoting thrombosis. In most reported cases including our own, it took a relatively long time until the cause of the disease as traumatic was found and accepted. The initial repetitive blunt or single severe trauma initiating the HHS can easily be overlooked or ignored. After intimal damage of a. ulnaris, the beginning of symptoms may be prolonged and mislead one into thinking the cause is a collagen or vasospastic disease.

Adult↗