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Biomedical subjects

V Mooney

Publications and source records attributed to V Mooney.

At least 73 records · Page 4Linked to original sources
PubMed1988

Objective evaluation of insert material for diabetic and athletic footwear.

Five of the most commonly used materials for shoe inserts (soft Plastazote, medium Pelite, PPT, Spenco, and Sorbothane) were objectively evaluated in the laboratory to characterize their behavior in the following three specific functions that correspond to clinical use: (1) the effect on the materials of repeated compression. (2) the effect of a combination of repetitive shear and compression. (3) the force-distribution (force-attenuation) properties of these materials, both when new and after repeated compression. The last function represents a model for relief of pressure beneath plantar bony prominences, a topic of special concern for the insensitive foot. All materials were effective in reducing transmitted force over the simulated bony prominence with a rank order of effectiveness. Other factors considered were: amount and rate of permanent deformation offset by considerations of enhanced moldability when comparing the neoprene and urethane materials with the polyethylene foams. The ideal insert represents a combination of material to achieve both durability and moldability.

Foot Diseases↗
PubMed1988

The failed back--an orthopaedic view.

The causes of the failed back syndrome are several. The failure to appropriately identify the structural sources of pain is one. The identities may include radiographically controlled injection procedures. The failure to use sufficiently discrete surgery with an attempt to avoid scar is another cause and the failure to provide an opportunity to avoid and later treat deconditioning is another. The appropriate treatment programme is based on objective assessment of function. Functional achievement as the principal care rather than pain self-report is the most effective manoeuvre to avoid the chronic pain of the failed back syndrome.

Back Pain↗
PubMed1987

A prospective two-year study of functional restoration in industrial low back injury. An objective assessment procedure.

One hundred sixteen consecutive patients entered a functional restoration treatment program for chronic low back pain and were compared with 72 patients not treated. A two-year follow-up survey reached more than 85% of both groups; its findings were compared with earlier results of a five-month and one-year follow-up. Analysis demonstrated that 87% of the treatment group was actively working after two years, as compared with only 41% of the nontreatment comparison group. Moreover, about twice as many of the comparison group patients had additional spine surgery relative to the treatment group. The comparison group continued with an approximately five times higher rate of patient visits to health professionals in the second year as the treatment group. Also, treatment group reinjury rates were no higher than those expected in the general population, while nontreatment subjects had a higher incidence of reinjury. Finally, a small treatment "dropout" group did poorest of all, with results in almost all areas even worse than those of the comparison group patients.

Adult↗
PubMed1987

Porous hydroxyapatite as a bone graft substitute in diaphyseal defects: a histometric study.

Porous hydroxyapatite (IP200), formed by conversion of the Poritidae porites exoskeleton, has pores averaging 230 microns and pore interconnections averaging 190 microns in diameter. In the distal radial diaphyses of 14 dogs, bilateral 7.5 X 20 mm cortical windows were created and fitted with 5 X 7.5 X 20 mm blocks of IP200 implants and iliac autografts. Both implanted and contralateral grafted radius specimens were retrieved at 3, 6, 12, 24, and 48 months. Unstained undecalcified sections were examined by microradiography and UV epi-illumination. Stained undecalcified sections were examined by light microscopy and quantitated by histometric methods. Implant specimens demonstrated good union and bone ingrowth at all time intervals. The implant specimens were composed of (mean +/- SE) 10.6% +/- 1.0% soft tissue, 51.2% +/- 1.3% bone, and 38.2% +/- 1.0% IP200. The graft specimens showed good union with little apparent ingrowth at 3 months, followed by progressive appositional closure of cancellous spaces. The graft specimens contained 21.9% +/- 0.9% bone at 3 months with increases at each time interval to 73.1% +/- 8.7% at 48 months. The volume fraction and mean width of IP200 did not change with time, confirming the absence of implant biodegradation. The volume fraction and mean width of bone remained stable in the implant but increased in the graft specimens, corresponding to graft neocortex formation. It is concluded that implants initially filled in with bone while grafts initially replaced much of their spongiosa and subsequently filled in with bone. Histometry of untreated defects and measurement of mechanical properties are suggested for further study.

Animals↗
PubMed1987

Experimental study on the repair of full thickness articular cartilage defects: effects of varying periods of continuous passive motion, cage activity, and immobilization.

In order to clarify the dose/response characteristics of continuous passive motion (CPM), the repair response of full thickness articular cartilage defects was studied in a rabbit model. The following combinations of CPM and immobilization (Imm) were utilized: CPM, 24 h/day; CPM, 8 h/day and Imm, 16 h/day; CPM, 2 h/day and Imm 22 h/day; Imm 24 h/day; and normal cage activity. These regimens were used only in the initial week and then all rabbits were permitted to move freely in their cages, except for a sixth Imm-CPM group that was kept immobilized in the initial week and then CPM 24 h/day for another week. The CPM 24 h/day and the CPM 8 h/day groups (groups 1 and 4, respectively) showed better repair than the other groups, i.e., better surface congruity, larger positive Safranin-O staining area, and greater number of chondrocytes in the repair tissue. The CPM 2 h/day group (group 3), however, showed only slightly better repair than the Imm group (group 4). The CPM following immobilization was not effective to overcome the harmful effect of immobilization. We conclude that in the present model, CPM for 8 or 24 h/day is effective for adequate cartilage repair even with some component of immobilization. Its application should be at least 8 h/day. On the contrary, if CPM is delayed for a week following immobilization, the effect of CPM on cartilage will be reduced.

Animals↗
PubMed1987

Coralline hydroxyapatite bone-graft substitutes in a canine diaphyseal defect model. Radiographic-histometric correlation.

Radiographic and histometric evaluation of a new form of bonegraft substitute derived from reef-building sea coral was performed in a canine diaphyseal defect model. Comparably sized blocks of this material and iliac crest autograft were placed into bilateral surgically created cortical windows in the distal radial diaphyses of 14 dogs. Representative graft specimens of both types underwent densitometric radiography and harvesting at 3, 6, 12, 24, and 48 months. Histometric analysis of implant specimens revealed satisfactory union and native osseous ingrowth at all time intervals. Graft specimens exhibited adequate union with scant host bone ingrowth at three months, but subsequent progressive appositional closure of cancellous spaces during the ensuing 45 months. Volume fraction and mean width of host bone remained stable in the implants but increased in the grafts due to neocortex formation. Stereologic distribution of bone was homogeneous in both implant and graft specimens, and no evidence for biodegradation of the former was observed. Corrected transmission density determinations accurately reflected these differences but correlated significantly with volume fractions and tissue widths of bone and soft tissue only in the autografts. These results support the successful early application of coralline hydroxyapatite bone graft substitutes as an alternative to autogenous grafting in the clinical setting and emphasize the potential role of noninvasive densitometric techniques in monitoring the incorporation of bone-graft materials.

Absorptiometry, Photon↗
PubMed1987

Dallas discogram description. A new classification of CT/discography in low-back disorders.

A new classification method for CT/discography was developed. The Dallas discogram description (DDD) related five separate categories of information. Degeneration and annular disruption were regarded as separate phenomena. Additionally, provoked pain response, contrast volume, and miscellaneous information were recorded. Discogram findings of 59 patients with low-back and/or leg pain were graded according to the new method and compared with standard methods using routine anteroposterior and lateral discographic images. Findings from routine discography and CT/discography were graded and correlated with myelographic and plain computerized axial tomography (CAT) scans. This study demonstrated that the contrast-enhanced axial view provided by CT/discography served as a useful projection for demonstrating disc pathology. CT/discography analyzed according to DDD offered a more sensitive discriminator of disc degeneration from annular disruption (disc protrusion/leaking). This evaluation can be recommended as the procedure of choice when revision of spine surgery is considered or when there is an equivocal or negative correlation between clinical information and myelography or CAT scan.

Adult↗
PubMed1987

The relationship of pain provocation to lumbar disc deterioration as seen by CT/discography.

The CT/discographic findings from 225 discs in 91 low-back pain patients were compared to the pain provocation during the injection of contrast into the disc. The radiographic appearance of disc deterioration demonstrating disc degeneration and annular disruption of each disc was classified separately using a fourpoint scale: normal, slight, moderate, or severe. Pain reaction to the discogram at each level was recorded as follows: no pain, dissimilar pain, similar pain, or exact reproduction of the patient's clinical pain. This more precise analysis demonstrated a significant relationship between pain and deterioration of discs. The CT/discogram presents an axial view of the disc that allows a subgrouping of disc deterioration that can discriminate between peripheral deterioration (degeneration) and internal deterioration (disruption). The disruption supposedly occurs earlier and is more likely to be the source of exact pain reproduction.

Adult↗
PubMed1987

The value of the axial view in assessing discograms. An experimental study with cadavers.

The clinical value of discography is controversial. An axial view of a discogram such as could be obtained with CT scans should increase the structural information regarding disc pathology, and clarify the relationship to disease of the facet joints as well. To evaluate this concept, 103 intervertebral levels in 23 cadaver specimens were studied by anteroposterior, lateral, and axial roentgenographic views. From these three views, a new classification for interpreting discograms was developed. The correlations between the three different views were good, confirming the potential value of CT axial views. However, in one fourth of the discs there were pathologic anatomic findings that could be seen only in the axial views. There were more severe osteoarthritic changes in the right than the left facet joint, and a discrepancy between facet arthritis and disc disease was also noted.

Adult↗
PubMed1987

Automated percutaneous diskectomy: initial patient experience. Work in progress.

A new method has been developed for percutaneously decompressing herniated lumbar disks. The method entails gaining access to the disk space through the use of an introduction system and a cannula. A 2-mm aspiration probe called a Nucleotome is then placed through the cannula into the disk space, and the nucleus pulposus is aspirated. Thirty-six patients have undergone the procedure, with a successful result in 31. There were no significant complications encountered, and the procedure is now being done on an outpatient basis. These preliminary results indicate that automated percutaneous diskectomy has the potential to replace laminectomy in the treatment of uncomplicated herniated disks.

Humans↗
PubMed1987

Impairment, disability, and handicap.

It seems clear that the orthopedic surgeon cannot separate impairment from disability. The measurement of impairment is clouded by the inability to measure dynamic function. A range of motion demonstrated by a patient in the doctor's office does not fully describe the functional potential of either the extremity or the spine. Moreover, the rules by which disability is defined are interpreted with a natural sympathy of the physician's care for the patient. The physician may have less sympathy if the individual being reviewed is a client of an insurance company or of an attorney, compared to being a "private" patient. In the future, the orthopedic surgeon would focus on the musculoskeletal handicap rather than disability, or function rather than impairment. Function must be measured in a dynamic manner. The guidelines for definition of function or dysfunction should be similar to those used in sports medicine regarding the decision as to when the athlete can resume sports. What was the capacity before injury? How close to the normal capacity has medical care restored function? This includes measurements of passage of time and consideration of the desire to return to previous activity. The goal is the development of methods that will accurately measure dynamic musculoskeletal function. Visceral organ systems have biochemical standards of measurement; comparable standards must be devised for the musculoskeletal system.

Back Pain↗
PubMed1987

Myoelectric spectral analysis and strategies for quantifying trunk muscular fatigue.

Objective techniques for assessing trunk musculature with respect to fatigue-related characteristics do not exist. Based on work that relates frequency spectral shift in myoelectric signals to muscular fatigue at other body sites, a study was carried out to investigate and evaluate strategies for application of these techniques to the lumbar musculature. Through evolution of test administration procedures to reduce test time and discomfort as well as data interpretation methods to account for interindividual variability observed in data, an approach was developed for objective measurement of fatigue rate. While abdominal and lumbar muscle groups were assessed in 40 healthy subjects with results presented for 50% and 100% maximum voluntary contraction load levels, the methodology is discussed with emphasis on erector spinae results. The approach involves a normal function fatigue plot. The plot relates fatigue rate as measured by myoelectric spectral characteristics to muscle load normalized by body weight and is independent of the maximum voluntary contraction concept. This relationship forms the basis of comparison of the measured fatigue rate for a subject with questionable function to expected normal values determined from the plot, given the measured load level.

Adult↗
PubMed1986

Coralline hydroxyapatite bone graft substitutes in a canine metaphyseal defect model: radiographic-biomechanical correlation.

Radiographic and biomechanical assessment of a new type of bone graft substitute derived from reef-building sea coral was performed in a canine metaphyseal defect model. Blocks of this material and autogenous iliac crest graft were implanted, respectively, into the right and left proximal tibial metaphyses of eight dogs. Qualitative and quantitative radiographic evaluation was performed in the immediate postoperative period and at 6 months after surgery. Biomechanical testing was carried out on all grafts following harvest at 6 months, as well as on nonimplanted coralline hydroxyapatite and autogenous iliac cancellous bone. In contrast to autografts, incorporation of coralline implants was characterized by predictable osseous growth and apposition with preservation of intrinsic architecture. Greater percent increase in radiographic density, higher ultimate compressive strength, and lower stiffness with incorporation were documented advantages of coralline hydroxyapatite over autogenous graft. Densitometric measurements correlated moderately with strength for both types of graft material (r = -0.65). These promising results have important implications to the clinical application of coralline hydroxyapatite bone graft substitutes as an alternative to autogenous grafting.

Absorptiometry, Photon↗