Biomedical subjects

P Afshar

Publications and source records attributed to P Afshar.

3 recordsLinked to original sources

PubMed2002

Hydroxyapatite/calcium carbonate (HA/CC) vs. plaster of Paris: a histomorphometric and radiographic study in a rabbit tibial defect model.

The search for an ideal bone substitute is ongoing. Multiple osteoconductive bone substitutes are available today. Plaster of Paris (POP) (calcium sulfate) has been used for more than 100 years for treatment of skeletal defects. This implant is compared to a new material, hydroxyapatite/calcium carbonate (HA/CC), in a rabbit tibia model. HA/CC is made from partial conversion of coralline calcium carbonate to hydroxyapatite and has an outer hydroxyapatite layer and an inner calcium carbonate core, a combination that leads to faster resorption than that of pure hydroxyapatite. This study compares the histomorphometric and radiographic properties of POP and HA/CC in a rabbit tibial defect. Both implants preferentially restore bone to the cortex relative to the canal. Plaster of Paris was fully resorbed by 6 weeks both radiographically and histometrically and HA/CC was substantially resorbed by 42 weeks. No significant difference was noted in volume fraction of bone between the two implants at 42 weeks postimplantation. Hydroxyapatite/calcium carbonate is a biocompatible bone graft substitute with a rate of resorption significantly slower than plaster of Paris.

Animals↗

PubMed2001

Predicting complications in elderly patients undergoing lumbar decompression.

A retrospective chart review of 68 patients 70 years of age or older who underwent decompressive procedures of the lumbar spine with or without fusion for benign conditions was performed to determine the ability of preoperative assessment of medical comorbidities to predict early postoperative complications. Patients 70 years of age or older who underwent decompressive procedures on the lumbar spine with or without fusion from January 1, 1990 to June 30, 1996 were identified. A chart review focused on preoperative comorbid diseases and early postoperative complications. A telephone survey was performed to assess patient satisfaction. Thirty-four women and 34 men with an average of 76.5 years averaged 1.6 comorbidities. Thirteen patients did not have comorbidities. The weighted comorbidity index resulted in an average score of 1.9. Eighty-five percent of the patients underwent posterolateral fusion. The total complication rate was 40%. Serious complications potentially affecting quality of life occurred in 12% of patients. The early mortality rate was 1.4%. The authors were unable to show a significant relationship between comorbidities and postoperative complications. Seventy-one percent of the 44 patients who were contacted at an average 42 months postoperatively were satisfied with their outcome. Elderly patients can safely undergo lumbar spinal procedures with an outcome similar to younger patients.

Aged↗

PubMed2000

Skeletal muscle response to tenotomy.

Tenotomy is a commonly encountered clinical entity, whether traumatic or iatrogenic. This article reviews the response of skeletal muscle to tenotomy. The changes are subdivided into molecular, architectural, and functional categories. Architectural disruption of the muscle includes myofiber disorganization, central core necrosis, Z-line streaming, fibrosis of fibers and Golgi tendon organs, changes in sarcomere number, and alterations in the number of membrane particles. Molecular changes include transient changes in myosin heavy chain composition and expression of neural cell adhesion molecule (NCAM). Functionally, tenotomized muscle produces decreased maximum tetanic and twitch tension. Alterations in normal skeletal muscle structure and function are clinically applicable to the understanding of pathological states that follow tendon rupture and iatrogenic tenotomy.

Animals↗