Biomedical subjects

E Diao

Publications and source records attributed to E Diao.

28 records · Page 2Linked to original sources

PubMed1996

Effect of peripheral suture depth on strength of tendon repairs.

The peripheral suture in flexor tendon repairs was originally introduced to "tidy up" the repair site and to improve gliding after core suture placement. More recently, it has been proposed that the peripheral suture can be an important structural component of tendon repair; yet, the effect of peripheral suture technique as an independent factor on the strength of the tendon repair has had little attention. We proceeded to determine whether differing levels of penetration of the tendon by the peripheral suture significantly affect the strength of the repair. We performed tensile tests on two groups of fresh frozen cadaver flexor digitorum superficialis tendons that had lacerations repaired by modified Kessler core sutures: one group had supplemental superficial peripheral sutures while the other group had supplemental deep (half the depth to the center of the tendon) peripheral sutures. The mean failure load of the deep peripheral suture group (38.96 N) was almost 80% greater than that of the superficial suture group (21.68 N). This increased strength may be due to an improved tendon-suture interface, with the deep peripheral suture acting as an auxiliary core suture. Our results with deep peripheral sutures, a simple technique based on a modification of commonly employed suture patterns, demonstrate substantially improved repair strength. This suture has the potential to be used in conjunction with early active finger motion rehabilitation program after flexor tendon repair.

Biomechanical Phenomena↗

PubMed1996

Congenital hypoplasia of the extensor tendons of the hand.

An 18-year-old woman with congenital flexion contractures of the ulnar three digits bilaterally is presented. She had a three-generation family history of this disorder with autosomal dominant inheritance. Magnetic resonance imaging scan of the wrist and forearm was used to demonstrate a hypoplasia of the digital extensor muscles and tendons.

Adolescent↗

PubMed1995

Comparative mechanical analysis of dorsal versus palmar placement of core suture for flexor tendon repairs.

This study was designed to evaluate the effect of core suture placement in the coronal plane on the tensile strength of flexor tendon repairs. We compared the tensile strength of modified Kessler core sutures placed in the palmar versus the dorsal side of matched-lacerated human cadaver flexor digitorum profundus tendons tested in vitro under static loading. We also compared the relative strengths of the dorsal and palmar portions of the flexor digitorum tendons. The mean failure load of a dorsal-side modified Kessler suture was 26.5% greater than that of a palmar-side modified Kessler suture. The mean strength of the dorsal half of the flexor digitorum tendons was 58.3% greater than that of the palmar half of the flexor digitorum tendons. Our data demonstrate that the dorsal tendon can sustain greater loads-to-failure than the palmar tendon. This suggests that there are biomechanical advantages to dorsal as opposed to palmar placement of the core suture in clinical tendon repair.

Cadaver↗

PubMed1994

Morphologic changes following endoscopic and two-portal subcutaneous carpal tunnel release.

This study describes the morphologic changes that occur following single incision endoscopic and two-portal subcutaneous carpal tunnel release. Seventeen patients were studied preoperatively and an average of 24 weeks postoperatively. Canal volume, carpal arch width, and median nerve palmar displacement and cross-sectional area were measured by use of multiplanar reformation and three-dimensional reconstruction of magnetic resonance images. Both methods produced a marked increase in canal volume and median nerve cross-sectional area; neither resulted in a significant change in carpal arch width. These data provide a morphologic basis for the belief that endoscopic or subcutaneous carpal tunnel release will produce clinical relief equivalent to open carpal tunnel release.

Carpal Tunnel Syndrome↗

PubMed1994

Mallet finger: results of early versus delayed closed treatment.

The efficacy of continuous splinting was retrospectively compared in two populations of 40 patients with soft tissue and bony mallet finger whose treatment was initiated within 2 weeks after injury (early) or more than 4 weeks after trauma (delayed). Splint treatment was successful in restoring active extension (with no more than 10 degrees extensor lag) in 17 of 21 patients in the early group and 15 of 19 patients in the delayed group. Neither the presence or absence of dorsal lip fracture less than one third of the articular surface of the distal phalanx nor the type of splint used affected the final outcome. Splinting was as effective in the delayed treatment population as it was in the early treatment population.

Finger Injuries↗

PubMed1993

Total collateral ligament excision for contractures of the proximal interphalangeal joint.

The complete excision of scarred proximal interphalangeal collateral ligaments as the cornerstone of surgical treatment for proximal interphalangeal joint contractures was evaluated. Supplemental palmar plate distal release, extensor tenolysis, and flexor sheath release were performed as needed. Sixteen patients with primary proximal interphalangeal joint contractures treated by this method were reviewed with the use of preoperative data obtained from chart review and postoperative data from direct patient examination. The average range of motion increased from 38 degrees to 78 degrees. No patients had instability of the proximal interphalangeal joints on manual testing and x-ray examination. This radical surgical approach to contracted proximal interphalangeal joints is justified by the improved range of motion without instability.

Adult↗

PubMed1992

Common tumors.

Common tumors of the hand and upper extremity are, by definition, benign conditions. There is a predictable pattern of occurrence and presentation for many of these lesions. The practitioner should always bear in mind, however, that any tumor that appears anywhere in the body can appear in the hand and upper extremity. Moreover, several of the benign conditions can, in certain clinical settings, have a predilection for transformation or association with more aggressive conditions. We would emphasize that the approach to any tumor be carefully considered and include an appropriate differential diagnosis. Any suspicious lesion should be examined thoroughly, including first-order screening tests, history, physical examination, radiographic imaging, and laboratory evaluations followed by more detailed diagnostic imaging prior to surgery. Surgery should be approached as a biopsy, with the possibility of frozen section analysis, and the possibility of a two-staged operation for tumor removal with appropriate margins if necessary.

Bone Neoplasms↗

PubMed1989

Kinetic and biochemical heterogeneity in vertebrate chondroepiphyseal regions during development.

The purpose of this study was to see if kinetic and biochemical heterogeneity could be documented in vertebrate chondroepiphyseal regions as they develop from mesenchymal condensations to cartilage. The kinetics of developing proximal and distal femoral chondroepiphyseal regions were studied from early limb bud stage to newborn animals in chicks, mice, and rabbits with thymidine autoradiography. Proteoglycan synthesis in the proximal femoral chondroepiphyseal region of the rabbit was studied with radioactive sulfate incorporation at 28 days of gestation and at 1 and 4 days after birth. The results indicated that these kinetic and biochemical characteristics of the developing chondroepiphyseal regions became heterogeneous very early in development. This early programming of populations of cells for division and for different biochemical functions existed during the fetal period when heterogeneity has been described histologically but has not been well documented.

Animals↗

PubMed1980

Lymphocyte antigens in systemic lupus erythematosus: studies with heterologous antisera.

Rabbit antisera were produced against pooled living lymphocytes from 25 patients with active systemic lupus erythematosus (SLE). Lymphocytes collected at plasmapheresis or venipuncture were frozen in liquid nitrogen and later coated with rabbit antibody to normal human tonsils and normal thymocytes immediately before intravenous immunization of rabbits. Antisera were subsequently extensively absorbed with normal human tonsillar cells, thymocytes, peripheral blood lymphocytes, erythrocytes, and leukocytes from patients with myelogeneous and lymphatic leukemia until residual base-line immunofluorescent staining of normal human lymphocytes using F(ab)2' of whole antisera averaged less than 5%. Absorbed pepsin-digested antisera detected membrane antigens which were markedly increased (mean 32%) on lymphocytes from patients with active SLE (P less than 0.05). Membrane antigens reacting with absorbed, pepsin-digested antisera were present on both T and B cells but, in most instances, predominated on T cells. Control observations using absorbed pepsin-digested antisera to normal human lymphocytes or peripheral blood lymphocytes from patients with rheumatoid arthritis showed no similar specificity. SLE patients treated with moderate or high dose corticosteroids or immunosuppressive agents (cytoxan or azathioprine) appeared to lose lymphocyte antigens detected by these reagents. Control studies with other connective tissue disease patients, miscellaneous hospitalized subjects, or normal controls showed low levels of reactivity (2-5%). SLE lymphocyte membrane antigens uniquely increased during active disease; this may represent neoantigens or alterations associated with the disease itself.

Adult↗

PubMedDate not supplied

In vivo studies of an implantable energy convertor for skeletal muscle powered cardiac assist.

A device that harnesses the mechanical energy of skeletal muscle contracting in a linear configuration has been implanted in goats. This energy convertor transforms muscle work to hydraulic energy that could drive a variety of cardiac assist devices. The device is mounted with a rib clamp and plate affixed to the sternum by cortical bone screws. A transcutaneous hydraulic line carries a silicon based working fluid to an external system that controls the muscle load. In 60 to 70 kg goats, the latissimus dorsi insertion was reattached to the energy convertor. A Telectronics myostimulator with intramuscular electrodes stimulated the latissimus dorsi. In acute implants, hydraulic pressures in excess of 150 psi were obtained. Chronic implantation of the device allowed system evaluation in the conscious unanesthetized animal. Two weeks after implant, hydraulic pressures in excess of 200 psi were obtained and energy transferred to the external loading system exceeded 1 J per contraction. Six weeks after implant, the device continued to cycle freely. These initial results are very promising and suggest an implantable energy convertor is feasible. Development of an energy convertor is an important step toward tether-free skeletal muscle powered cardiac assist devices.

Animals↗