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Biomedical subjects

D T Sowa

Publications and source records attributed to D T Sowa.

12 recordsLinked to original sources

Symptomatic proximal translation of the radius following radial head resection.

Eight patients with symptomatic proximal translation of the radius after having radial head resection for trauma were treated with a combination of immediate pinning of the radius to the ulna, silicone radial head replacement, or some form of ulnar shortening, including the Darrach procedure, formal ulnar shortening, or Suave-Kapandji fusion. Despite these techniques, all patients did not maintain effective relative length of the radius, exhibiting 3 mm or greater positive ulnar variance after treatment. Injuries to the central band of the interosseous membrane of the forearm probably do not heal with mechanical integrity. Without this structure, conventional methods of equalization of the radius and ulnar do not appear to be reliable. Current methods of treatment of acute longitudinal dissociation of the radius and ulna are inadequate.

Adult

Mixed gonococcal and mycobacterial sepsis of the wrist.

Mycobacterial infections of the hand and wrist are rare. Concurrent infection of a joint by more than one organism is also unusual. A 25-year-old man developed wrist sepsis caused by Neisseria gonorrhoeae and Mycobacterium avium intracellularis. The infection was successfully treated by wrist drainage, carpal debridement, and intravenous antibiotics. Secondary carpal reconstruction was accomplished by delayed bone grafting and internal fixation to preserve radiocarpal motion.

Adult

An anatomic and mechanical study of the interosseous membrane of the forearm: pathomechanics of proximal migration of the radius.

The interosseous membrane of the forearm of 12 fresh cadaver specimens was studied anatomically and mechanically to better understand its role in stabilization of the radius after radial head excision. A central band of ligamentous tissue, approximately twice the thickness of the membrane on either side was identified in all specimens. Mechanical studies determined the relative contribution to longitudinal stiffness of the forearm. The central band was responsible for 71% of the longitudinal stiffness of the interosseous membrane after radial head excision. The contribution of the triangular fibrocartilage complex was 8%. Silicone radial head implants were much less stiff than the intact interosseous membrane. Injury to the central band of the interosseous membrane may be crucial to the development of proximal migration of the radius after radial head excision.

Biomechanical Phenomena

Application of magnetic resonance imaging to ischemic necrosis of the lunate.

Twenty patients (22 wrists), in whom ischemic necrosis of the lunate was suspected clinically, were studied prospectively by physical examination, conventional radiography, radionuclide bone scintigraphy, and magnetic resonance imaging. Magnetic resonance imaging showed more specificity than radiography or radionuclide bone imaging in making the diagnosis of ischemic necrosis of the lunate. Two patterns of lunate signal defect were seen on magnetic resonance imaging with focal or generalized signal loss on T1-weighted and T2-weighted images. Generalized loss of lunate signal on T1-weighted images was diagnostic for ischemic necrosis of the lunate. Focal signal loss on the radial one half of the lunate suggested early involvement. Normal or increased signal on the corresponding T2-weighted image implied an earlier stage and a better prognosis. Magnetic resonance imaging evaluation of the lunate may be useful for subclassification of Lichtman's radiographic stage 2 and can be employed to follow lunate revascularization after treatment. Magnetic resonance imaging is a low risk, noninvasive diagnostic technique, which can modify diagnosis, staging, treatment and prognosis of ischemic necrosis of the lunate.

Adolescent

Ankle fusion: a new technique of internal fixation using a compression blade plate.

A new technique of tibiotalar arthrodesis has been developed offering wide exposure, excellent correction of deformity, good bony apposition, and blade plate fixation. This technique has even been effective in cases of ischemic necrosis of the talus. A modified pediatric blade plate is used to effect compression of the talus to the tibia and to provide stability against flexion/extension and varus/valgus movement. Fixation is augmented by a lateral fibular struct screwed to the tibia and talus. In this series, 17 compression blade plate tibiotalar arthrodeses were performed. Follow-up averaged 48 months (range 13 to 85 months). Preoperative diagnoses included postraumatic degenerative arthritis, rheumatoid arthritis, and ischemic necrosis of the talus. Solid fusion was achieved in 16 of 17 patients (94%) with a painless, stable pseudarthrosis in the remaining one. Time to fusion averaged 4 months (range 2 1/2 to 6 months). Functional clinical results were excellent in 12 and good in 4 patients. Of 14 patients evaluated by the Mazur scale, 10 scored within the range of excellent; 2, good; and 2, fair.

Aged

Congenital pseudarthrosis of the forearm.

Congenital pseudarthrosis of the forearm is a rare condition in which traditional treatment methods have proven unsatisfactory. We report a case of congenital pseudarthrosis of the radius and ulna successfully treated by resection of the distal ulna and excision of the radial pseudarthrosis with replacement by an interpositional free vascularized fibular graft.

Child, Preschool

Extraskeletal osteochondromas of the wrist.

Extraskeletal osteochondromas of the wrist are described in two patients. They both had painless, slow-growing wrist masses, one palmar and one dorsal. Radiographs demonstrated the presence of an extraskeletal, radiopaque mass. Excisional biopsy showed extraskeletal, firm, calcified masses. Histologic examination revealed mature hyaline cartilage, with extensive ossification consistent with the diagnosis of extraskeletal osteochondroma. The ambiguous nomenclature for this cartilage lesion and the differential diagnosis of extraskeletal calcification are reviewed.

Aged

Clinical applications of vascularized bone autografts.

Our experience with microvascular transfer of fibular grafts and composite osteocutaneous iliac flaps has shown that massive autogenous bone grafting with an intact vascular pedicle decreases the time to bony union and the duration of immobilization required for functional reconstruction of an extremity. The technique has proven reliable (87 per cent success rate) in the reconstruction of bone defects of greater than 6 to 8 cm following tumor resection or defects existing in a fibrotic, avascular bed. More importantly, these techniques have been applied for limb salvage in patients with tumors or with severely traumatized extremities that were not candidates for more traditional methods of bone grafting. In many cases, amputation would have been the only alternative.

Adult

Polymicrobial polyarticular septic arthritis.

A bacteriology technologist was found to have acute polyarticular arthritis after a brief prodromal illness. Gram's stain of fluid from the right knee showed pleomorphic gram-negative organisms, while that of fluid from the right elbow and left wrist showed gram-negative cocci and diplococci. Culture of fluid from the right knee yielded Salmonella enteritidis. Cultures of fluid from all other joints, collected after starting therapy, were negative. An enzyme-linked immunosorbent assay of fluid from the right elbow confirmed Neisseria meningitidis, group C. This organism was also isolated from the patient's throat. This case represents concurrent infection of separate joints by two bacterial pathogens, one confirmed by culture and one by current immunodiagnostic techniques.

Adult

Electrophoretic determination of charge on carrier-free 99mTc-labeled complexes.

A new method for determining the charge on carrier-free 99mTc-labeled complexes is described. This method and mixed-ligand experiments were used to determine if the charge on the technetium 99m complex of N-(2,6-dimethylphenylcarbamoylmethyl)iminodiacetic acid (I) is - 1 and if the ligand to technetium ratio in the complex is 2:1. The preparation of an iodinated analog (II) of I and its 99mTc-labeled complex is described, as is the biodistribution of the 99mTc-labeled complex in mice. The synthesis of the 51Cr(III)- and 57Co(III)-labeled complexes also are described. The net biliary excretion in mice of both the 99mTc- and 51Cr-labeled complexes of II was significantly greater than that of the 99mTc-labeled complex of I.

Animals