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Biomedical subjects

V Mooney

Publications and source records attributed to V Mooney.

134 records · Page 8Linked to original sources

Neurocirculatory disorders of the foot.

There is a simple rationale for care of the dysvascular neuropathic foot. Either prevention or correction of deformities, or both, is of primary importance in the insensitive or poorly healing foot. Control of edema is necessary to achieve maximum healing potential. There are tools at hand to allow the orthopedic surgeon to judge arterial supply in addition to his clinical judgment. Interest in defensive footwear, appreciation of interface forces, and the application of standard operative techniques to this ever-present population can result in significant improvement in patient care.

Amputation, Surgical↗

Resorbable structured porous materials in the healing process of hard tissue defects.

The long-term goal of this research is to assist the resurfacing of damaged articular cartilage. Coralline hydroxyapatite (HA) was coated with a thin film of polylactide (PLa), maintaining pore structural characteristics. Cylindrical plugs (3 x 7 mm) implanted in non-load-bearing femoral and tibial diaphyses of the rabbit indicated substantial bone ingrowth at 3 weeks, with no significant difference between coated and uncoated HA in the amount and distribution of new bone. PLa-epsilon caprolactone polymeric negative replicas of coral Goniopora (G), inserted into the rabbit femur for 4 wks, showed newly formed bone grown deeply into the pores. Tight attachment of new bone to the implant and minimal inflammatory response suggested an osteocompatible reaction. In order to maintain the desirable pore structure of G while introducing controllable degradation rate and mechanical properties, a novel technique was employed to replicate G with PLa and its co-polymers. An intermediary negative replica of G was prepared with aspirin. A co-polymer positive replica of G was then prepared by solution or melt infusion into the negative replica; the aspirin was removed by methanol. A macro- (300-500 microns) and microporous (5-15 microns) structure was prepared by freeze-drying. This replica received appreciable bone ingrowth when implanted in the rabbit tibia for 3 wks. Our results demonstrate the feasibility of creating devices with interconnected pore structures and controlled porosity, elasticity, and mechanical strength sufficient for articular cartilage application, osteocompatibility, and controlled degradation rate.

Animals↗

Quantification of lumbar function. Part 5: Reliability of range-of-motion measures in the sagittal plane and an in vivo torso rotation measurement technique.

Intra- and intertester reliability of a previously described technique for measurement of sagittal plane lumbar spine motion was assessed. Results demonstrated a high degree of reliability of this technique. Sagittal plane norms for men and women are also presented. In addition, a pilot study of a simple in vivo measurement method for lumbar torsion is described and tested on a group of control subjects and a group of chronic low-back pain patients.

Adult↗

Granular tricalcium phosphate in large cancellous defects.

Tricalcium phosphate (TCP) is a porous ceramic which has biological properties of being non-reactive and resorbable, and acts as a scaffolding for bone ingrowth, undergoing progressive degradation and replacement by bone. Tricalcium phosphate has been shown to be comparable to autogenous bone graft in small periodontal defects. However, orthopedic defects are much larger. This prompted us to review the bone ingrowth potential in large cancellous bone defects (up to 12 cm3) in adult pigs. To quantitate bone ingrowth potential, three skeletally mature pigs had metaphyseal defects created in the tibia and femur of each hind limb, for 12 total sites. Twelve-cc defects in the distal femur and eight cc defects in the proximal tibia were made. Bone curetted was saved to be used as autogenous graft in the control, while the other ipsilateral defect was packed with tricalcium phosphate. Four months following the initial defect, the opposite hind extremity was similarly operated. All animals were sacrificed at nine months. Specimens were imbedded in methyl-methacrylate, cut at 120 microns, and stained. The quantity of regenerated bone was measured by histomorphometric techniques. Qualitative assessment at four months revealed absence of inflammation and TCP surrounded by trabecular bone, which was uniformly viable. There was very little TCP left by nine months. Quantitative analysis revealed the tibias to have a higher percent net bone replacement with TCP as compared to the control (32 percent versus 13 percent). The femoral TCP-filled defects were comparable to autogenous bone (both measured 29 percent).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Magnetic resonance imaging of the lumbar spine with CT correlation.

The results of magnetic resonance (MR) imaging and computed tomography (CT) in 18 patients with known degenerative disk disease of the lumbar spine were compared. In 60 intervertebral disk levels studied, there were 17 disks with degeneration and disk bulge, and 15 herniated disks. Final diagnoses were based on several factors, with surgical confirmation in five patients. There was good correlation between the two methods at 51 of the 60 levels studied. However, there were major discrepancies in interpretation at nine intervertebral disk levels. These included three false-positive MR imaging interpretations of a herniated disk and one false-negative herniated disk on MR imaging. MR imaging detected one case of disk herniation that was missed prospectively on CT. There were also four presumed degenerated disks seen on MR scans that appeared normal on CT. The conus medullaris was imaged in 16 of 18 patients. The sagittal view proved best for demonstrating both disk abnormality and the conus medullaris. The transaxial view was sometimes helpful in localizing a disk herniation, but partial-volume averaging in the 7-mm slice thickness limited its usefulness. There were five disk herniations that could not be accurately localized on the MR scan. MR imaging proved more sensitive than CT in detecting early disk disease, which appeared as decreased signal intensity within the disk. In three postoperative cases, MR imaging was better able to distinguish between recurrent disk herniation and postoperative scar formation. CT, on the other hand, was more specific in distinguishing herniated disk from disk bulge and proved far superior to MR imaging in localizing disk herniation.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗