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Biomedical subjects

D Davidson

Publications and source records attributed to D Davidson.

282 records · Page 16Linked to original sources
PubMedDate not supplied

Comparison of Gianturco Z stents and Wallstents in a hemodialysis access graft animal model.

PURPOSE: To compare the primary patency of two structurally different metallic stents in an animal model of hemodialysis access grafts. MATERIAL AND METHODS: Nineteen synthetic femorofemoral arteriovenous shunts were created in 10 dogs. After a 1-month period of maturation (during which one graft thrombosed), stents were placed spanning the venous anastomosis. The grafts were divided into two treatment groups (Wallstent, n = 6, and Gianturco stent, n = 6) and a control group with no stent (n = 6). Fistulograms and pressure measurements were obtained at monthly intervals for 6 months or until thrombosis of the graft. RESULTS: Mean graft patency in the Wallstent group (112 days +/- 30) was significantly shorter than in the control (157 days +/- 32, P < .03) or Gianturco (157 days +/- 32, P < .05) groups. Patency in the Gianturco stent group was no different from that in the control group. Stenosis due to intimal hyperplasia within the stents appeared greater in the Wallstent group but did not achieve statistical significance. One Wallstent migration, three Gianturco stents shifts, and two Gianturco stent breakages occurred. Histologic examination revealed a necrotizing vasculitis in the portion of vein containing the stent in all grafts treated with the Gianturco stent but not in any other grafts. CONCLUSION: In an animal model of hemodialysis access grafts, the Gianturco stent had longer primary patency than the Wallstent when placed across the venous anastomosis. However, stent fractures and focal necrotizing inflammation may limit the use of the Gianturco stent in hemodialysis access.

Anastomosis, Surgical↗
PubMedDate not supplied

Younger and older adults' recall of typical and atypical actions from script-based text: evidence for interruption and bizarre-imagery effects.

In the present research, younger (mean age 20) and older (mean age 78) adults' perception and recall of scripted and nonscripted actions were examined. Two primary types of nonscripted or atypical actions were presented: those that interrupted the sequence of the script and those that were irrelevant to the script. Script-irrelevant actions also varied in terms of how plausible they were in relationship to both the sentence they were embedded in and the context of the story. Across experiments, both younger and older adults recalled script-interruptive actions better than all other actions, including script actions. In addition, an unexpected finding was that both younger and older adults recalled implausible (bizarre) script-irrelevant actions better than script actions. This latter finding suggests that a bizarre-imagery effect may operate in both younger and older adults. Older adults' better recall of atypical actions over script actions is noteworthy, as these results question the assumption that older adults show an increased reliance on their schematic knowledge structures to recall. Contrary to expectations, older adults showed better recall of actions that required more active story integration (interruptive and implausible atypical actions) than actions requiring less integration (script and plausible atypical actions).

Adolescent↗
PubMedDate not supplied

Atrial and venous thrombosis secondary to septic arthritis of the sacroiliac joint in a child with hereditary protein C deficiency.

Septic arthritis and osteomyelitis in children is seldom accompanied by calf vein thrombosis and rarely by atrial thrombosis. We report the case of an 11-year, 5-month-old boy with septic arthritis and osteomyelitis of the sacroiliac region who developed deep venous thrombosis, in addition to life-threatening right atrial thrombosis. After an intensive hematologic investigation, a hereditary protein C deficiency was revealed. The association of venous thrombosis with septic arthritis or osteomyelitis should raise the possibility of the presence of protein C deficiency.

Arthritis, Infectious↗
PubMedDate not supplied

The adolescent pilon fracture: management and outcome.

Pilon fractures in the adolescent are complicated by the presence of the adjacent physis. These fractures usually result from high-energy trauma, frequently associated with soft-tissue trauma, further potentiating treatment difficulties. Although rare, such fractures are associated with a high complication rate, including physeal arrest. It was the objective of this review to increase awareness of this fracture pattern in the adolescent, to determine the types of complications in this difficult group, and to develop a treatment plan to improve the outcome of treatment. Seven children, with a total of eight pilon fractures were treated at a major pediatric tertiary referral center over the past 10 years. The average age of the children was 15 years 10 months (range, 13 years 6 months to 17 years 7 months). The average length of follow-up was 16 months (range, 3 months and 3 years 10 months). There were three Reudi type II equivalent fractures and two Reudi type III equivalent injuries. Three fractures did not fit the Reudi classification system as there was an associated ankle dislocation. All fractures were treated with open reduction and internal fixation. There were two cases of posttraumatic osteoarthritis and one physeal arrest. Results were good to excellent in 63% of cases. A new classification system for pediatric pilon fractures has been proposed.

Adolescent↗
PubMedDate not supplied

Intraoral plexiform (multinodular) neurilemoma.

An intraoral (buccal) mass in a 6-year-old child was found to be a benign plexiform (multinodular) neurilemoma by fine-needle aspiration (FNA) biopsy cytology and histologic examination of the excised specimen. Clinical and pathological features of these rare tumors are reviewed, and the capacity of FNA to guide surgical planning in the pediatric population is emphasized.

Biopsy, Needle↗
PubMedDate not supplied

Q & A: AHA's Dick Davidson.

Alabama hospitals face an array of complex challenges and questions as the nation moves toward health care reform. We recently asked Dick Davidson, president of American Hospital Association, to explain some key aspects of AHA's position on reform and how it relates to the Clinton administration's proposal.

American Hospital Association↗
PubMedDate not supplied

The SAPHO syndrome in children: a rare cause of hyperostosis and osteitis.

The SAPHO syndrome is a rare constellation of signs and symptoms characterized by synovitis, acne, pustulosis, hyperostosis, and osteitis. The most common musculoskeletal complaints are hyperostosis, causing pain, tenderness, and swelling of the anterior chest wall, although any part of the axial and appendicular skeleton may be affected. There is a great degree of variability in the dermatologic involvement of this syndrome. A combination of clinical, radiographic, and pathological investigation is required to establish the correct diagnosis. No single treatment has been found to be effective, although nonsteroidal antiinflammatory drugs have been the most frequently used. Because there is no mention of SAPHO syndrome in the English orthopaedic literature, and pediatric orthopaedic surgeons may be the first caregivers to treat these children, we thought it appropriate to share our experience with a 5-year-old boy with SAPHO syndrome recently under our care.

Acquired Hyperostosis Syndrome↗
PubMedDate not supplied

Congenital synspondylism: diagnostic features.

Congenital synspondylism is a recently described condition characterized by short stature, an unusual constellation of vertebral fusions without rib anomalies and carpal coalition. A new case is described to illustrate the diagnostic features and the orthopaedic problems associated with this rare syndrome. Review of available literature shows that patients with congenital synspondylism commonly develop spinal deformity and mild respiratory compromise.

Adolescent↗
PubMedDate not supplied

Semitendinosus tenodesis for repair of recurrent dislocation of the patella in children.

Recurrent dislocation of the patella is more common in girls than in boys. Although several predisposing factors may exist, patellar dislocation is most commonly associated with familial ligamentous laxity. Many surgical repairs have been described to stabilize the patella. We have found the semitendinosus transfer to the patella to result in a predictable, stable patellofemoral joint without risk of injury to the proximal tibial physis. Between January 1990 and December 1997, 29 children have been treated at the Children's Hospital of Eastern Ontario with a semitendinosus transfer for recurrent dislocation of the patella. Seven children were excluded from the study because of insufficient follow-up; consequently this series consisted of 22 children. Four children underwent bilateral repairs, hence 26 knees that have been operated on with this procedure were included in this study. There were three boys and 19 girls, with an average age at surgery of 14 years and 4 months, ranging from 8 years and 11 months to 17 years and 10 months. The average length of follow-up was 3 years and 2 months, ranging between 2 years and 7 years and 4 months. All children had experienced greater than three episodes of recurrent dislocation of the patella. Pain consistent with patellofemoral syndrome or chondromalacia was present in 17 of 26 knees. On clinical examination, 10 knees exhibited marked ligamentous laxity. There were nine positive patellar apprehension tests, and eight patellae were hypermobile. All children were treated with a semitendinosus transfer to the patella with concomitant tightening of the medial retinaculum and a lateral retinacular release. On long-term follow-up, 23 of the 26 knees (88%) were asymptomatic, and the child had returned to regular activities. Each child completed the Lysholm and the subjective component of the Zarins-Rowe questionnaire to determine the subjective results of the repair procedure. Three children complained of patellofemoral symptoms. One child experienced recurrence of the patellar dislocation, and one child developed medical patellar subluxation.

Adolescent↗
PubMedDate not supplied

Severe hemorrhage from an arteriovenous malformation of the mandible: report of case.

A case of a potentially lethal arteriovenous malformation of the mandibular bone in a 6.5-year-old girl is reported. Diagnosis is often difficult and the AVM may be discovered only when a tooth is extracted. The intent of the preceding report is to alert dental practitioners to the need for immediate control of abnormal bleeding from an extraction socket, because of the potentially lethal consequences. Failure to respond quickly to profuse bleeding of this type could result in the death of the patient by exsanguination.

Arteriovenous Malformations↗