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Biomedical subjects

J G Seiler

Publications and source records attributed to J G Seiler.

61 records · Page 4Linked to original sources
PubMed1989

Intraoperative assessment of median nerve blood flow during carpal tunnel release with laser Doppler flowmetry.

Eleven consecutive median nerves in patients with clinical carpal tunnel syndrome were examined prospectively with laser Doppler flowmetry. All procedures were done without a tourniquet with the patient under local or general anesthesia. Multiple measurements of median nerve blood flow were obtained during carpal tunnel release. Flow characteristics proximal to the transverse carpal ligament did not change after release of the ligament. Beneath the transverse carpal ligament, initial flow was random in 10 of 11 nerves. Within 1 minute after release of the transverse carpal ligament, flow became pulsatile and synchronized with the patient's pulse in nine nerves. Although preliminary, these data suggest that in carpal tunnel syndrome the segment of median nerve beneath the carpal ligament is relatively ischemic and this ischemia may be a factor in the development of symptomatic median nerve entrapment. The rapid return of a pulsatile signal within the nerve after release is positively correlated with relief or improvement of median nerve dysesthesias.

Adult↗
PubMed1989

Correlation of the findings of magnetic resonance imaging with those of bone biopsy in patients who have stage-I or II ischemic necrosis of the femoral head.

A prospective study was undertaken to determine the diagnostic accuracy of magnetic resonance imaging in the evaluation of a symptomatic hip for which a diagnosis of early ischemic necrosis of the femoral head was suspected. Fifteen patients (sixteen symptomatic hips), for whom the findings of magnetic resonance imaging were consistent with a diagnosis of osteonecrosis of the femoral head, had a core decompression and a biopsy of the contents of the core. Preoperative magnetic-resonance imaging was useful for planning which segment of the femoral head should be biopsied. Plain radiographs and tomograms of the hips were also made. On the basis of the plain radiographs, ten hips were determined to have Stage-I findings and six hips, Stage-II ischemic necrosis, according to the system of Ficat and of Arlet and Ficat. Histological study revealed evidence of necrosis in all of the biopsy specimens of bone. We concluded that findings of magnetic resonance imaging that are characteristic of osteonecrosis correlate well with the results of biopsies of bone in patients who have an early stage of ischemic necrosis. Magnetic resonance imaging is a highly sensitive and specific method for both the diagnosis and the location of Stage-I and Stage-II osteonecrosis.

Adult↗
PubMed1986

Amputation after extremity injury.

Extremity injury is a significant cause of morbidity and mortality in the trauma patient. The decision to amputate is a difficult one to make in a patient population still in the productive years of life. At the University of Louisville Hospital from 1976 to 1984, 37 patients with traumatic extremity injury required amputation. Ninety percent of these injuries were to the lower extremities. A decision for amputation was based on the absence of neurovascular function, the presence of fracture of the involved extremity, the presence of a large soft tissue defect, and the presence of severe contamination. Prompt amputation of such severely damaged limbs may be preferable to attempts at salvage. Early amputation offers the opportunity for prosthetic replacement and good long-term functional recovery.

Adolescent↗
PubMed1986

Factors contributing to fatal outcome after treatment of pancreatic abscess.

The authors analyzed 27 patients with pancreatic abscess treated since 1975 at hospitals affiliated with the University of Louisville School of Medicine. Treatment consisted of careful debridement, abscess drainage, and multiple antibiotics in all patients. Overall mortality was 33%; however, only three of 17 patients treated since 1980 have died. Patients who died were more likely to have bacteremia, a residual abscess, multiple organ system failure, and/or polymicrobial growth on culture of the abscess. The proper use of soft suction drains in a dependent position reduced the rate of residual abscess to 19% compared to 67% in patients not treated in this fashion. The results identify factors that are correlates of death in patients with pancreatic abscess and emphasize the importance of prompt diagnosis and proper treatment.

Abscess↗
PubMedDate not supplied

Geometric properties and the predicted mechanical behavior of adult human clavicles.

An image processing system was used to examine histomorphometric properties of 15 adult male and female human clavicles. Variations in porosity, cross-sectional area, anatomic and principal moments of inertia were assessed at 2.5-5.0% increments along the length of the clavicles. The clavicle's biomechanical behavior (axial, flexural, and torsional rigidities and the critical force for buckling) was modeled from these data using beam theory. Over threefold variations in porosity and moments of inertia were found along the length of the s-shaped clavicle--the greatest porosity and moments of inertia were located in the variably shaped sternal and acromial thirds of the bone in contrast to the denser and smaller, more circulatory shaped central third of the bone. Clavicle orientation, as indicated by the direction of greatest resistance to bending (maximum principal moment of inertia), was found to rotate from a primarily cranio-caudal orientation at the sternum to a primarily anterior-posterior orientation at the acromion. Based on cross-sectional geometry, section moduli, and estimates of flexural and torsional rigidity, the clavicle was found to be weakest in the central third of its length. These data concur with the fracture location most commonly reported clinically. Analysis of Euler buckling predicted a minimum critical force for buckling during axial loading of approximately two to three body weights for an average adult. Thus, buckling, or a combination of axial loading and bending or torsional loading, must be considered as possible failure mechanisms for this commonly injured bone.

Acromion↗
PubMedDate not supplied

The distal biceps tendon. Two potential mechanisms involved in its rupture: arterial supply and mechanical impingement.

The purpose of this anatomic study was to evaluate potential causes of rupture of the distal biceps tendon, to assess the dynamic relationship of the proximal radioulnar joint during pronation and supination, and to identify potential sites of impingement of the distal biceps tendon. For the anatomic study specimens were evaluated by light microscopy, multiplanar gross dissections, and Spalteholz vascular injection. For the radiographic study computed tomography was used to assess dynamic changes in the radioulnar space in pronation, neutral position, and supination. Three vascular zones were identified in the distal biceps tendon. Vascular contributions were consistently noted from the brachial artery proximally and from the posterior recurrent artery distally. A hypovascular zone averaging 2.14 cm was evident between the proximal and distal zones. On sectioning through the proximal radioulnar joint 85% of the space was occupied by the distal tendon in full pronation. In addition, computed tomography imaging revealed a 50% reduction in the radioulnar joint at the radial tuberosity from full supination to full pronation. Mechanical impingement on the biceps tendon during forearm rotation and hypovascularity within sections of the tendon may contribute to attritional ruptures of the distal biceps tendon.

Cadaver↗