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Biomedical subjects

J R Neff

Publications and source records attributed to J R Neff.

106 records · Page 6Linked to original sources
PubMed1982

Knee arthrography for the preoperative evaluation of juxta-articular masses.

Knee arthrography was performed on twenty-one patients with osseous and extraosseous masses about the knee. Twelve patients had arthrographic abnormalities. Joint involvement was accurately delineated in nine of the ten cases where it was present. Three other patients had small suprapatellar bursae with superior flattening, characteristic of noncommunicating suprapatellar synovial cysts. Fluoroscopic spot radiographs and conventional radiographs after injection of contrast material adequately defined the synovial recesses. Tomograms were needed whenever articular cartilage invasion was a possibility. The arthrographic findings were useful in planning the operative approach in all cases except for the one case where the arthrogram did not detect the intra-articular invasion.

Adult↗
PubMed1982

Computed tomography in the preoperative evaluation of masses arising in or near the joints of the extremities.

Knowledge of the precise anatomical relationship of a mass lesion to a joint is helpful in the preoperative planning of surgery. We have evaluated this relationship in 23 patients with a variety of benign and malignant lesions related to the knee and other major joints. In 15 patients, the lesion-joint relationship was assessed by routine computed tomographic (CT) scans followed within 24 hours by arthrography. In nine of these 15 patients, CT demonstrated that the lesion either was remote from the joint or clearly invaded it, and arthrography could have been avoided in these patients. In six patients, the CT findings were indeterminate and further evaluation by arthrography was indicated. CT scans limited to the joint area and obtained immediately after arthrography were available in 14 patients. In general, postarthrography CT did not add significant information to that provided by prearthrography CT scans or by arthrography. However, it may be helpful in occasional cases in which arthrography is not definitive.

Adolescent↗
PubMed1981

Direct longitudinal computed tomography of the forearm.

A method is outlined for obtaining direct longitudinal computed tomograms of the forearm using a conventional total body scanner. A case is described in which longitudinal scanning helped define a soft tissue tumor of the forearm and thereby assisted in surgical planning.

Adolescent↗
PubMed1979

Comparison of computed tomography and other imaging modalities in the evaluation of musculoskeletal tumors.

An algorithmic approach for the evaluation of musculoskeletal tumors is proposed on the basis of a prospective comparison of different imaging techniques in 50 unselected patients. Conventional radiography was superior to other techniques in predicting the nature of primary bone tumors. Computed tomography proved the most effective method for assessing the extent of musculoskeletal tumors and therefore had a significant influence on management in 66% of patients studied. CT was more informative than angiography and also provided more anatomical detail than ultrasound. Radionuclide scanning was mainly of value in detecting unsuspected skeletal metastases in patients with apparently solitary skeletal lesions.

Adolescent↗
PubMed1978

Macrophages in giant cell tumours of bone.

Five giant cell tumours of bone were studied to determine the degree of macrophage infiltration and whether the giant cells expressed the characteristics commonly associated with macrophages, i.e., IgGFc and C3 receptors, phagocytosis and non-specific esterase activity. Macrophages were assessed in trypsin-derived tumour cell suspensions by IgGEAC rosette formation and in frozen sections of tumour by EA adsorption. The percentage of macrophages in cell suspensions from four of the tumours ranged from 11 to 40 per cent. Strong EA adsorption occurred over 35 to 95 per cent. of the tumours' surface and significant non-specific esterase positivity was observed in the tumour sections. The giant cells were receptor negative and non-phagocytic, but a low percentage of them expressed esterase activity. The results strongly suggest that despite the fact that large numbers of macrophages were present in the tumours, the giant cells were derived from cells other than macrophages.

Bone Neoplasms↗
PubMed1978

External skeletal fixation in severe limb trauma.

Ten patients with 12 severe limb injuries managed by external skeletal fixation over 2 years are presented. Two major indications for external skeletal fixation divided the fractures into groups: A) extensively open fractures requiring wound care and closure by other than primary methods, and B) grossly unstable fractures requiring stabilization for soft-tissue support and fracture alignment. Group A was composed of five extremity fractures with skin and muscle loss and deep tissue contamination. Wound management was the primary problem. Wound closure, prevention of an infection, and limb salvage were the treatment goals in this group. Group B was seven severely comminuted extremity fractures with significant swelling and in some cases, questionable soft-tissue survival. Five were open, but not extensively. Instability was the primary problem. Fracture control, soft-tissue support, and limb salvage were the treatment goals in this group. Mean followup period for all fractures was 9.4 months. No amputations, deep infections, or deaths resulted. Wound care and closure were facilitated in all open fractures. Loss of contused tissues with marginal vascular supply was felt to be minimized. Delayed unions were common in both groups. Two malunions and one nonunion occurred. Treatment goals in both groups were accomplished.

Adolescent↗
PubMed1978

A reevaluation of B-lymphocyte levels in peripheral blood from cancer patients.

B-lymphocytes were quantitated in mononuclear cell suspensions derived from the peripheral blood of patients with various nonlymphoreticular cancers. The method used was anti-IgM and anti-IgD membrane immunofluorescence. The mean percentage of circulating B-lymphocytes in 78 cancer patients tested was 5.3 +/- 4.6 with a range of 0--18%. Those values were compared with a mean of 9.4 +/- 4.0 and a range of 3--20% for 46 apparently normal individuals. The difference was highly significant (P less than or equal to 0.001). The mean percentage of B-cells in cell suspensions from 43 patients that were tested prior to treatment was 5.8 +/- 4.8 with a range of 0--18%. Very low values were observed both in the presence and absence of therapy, and a correlation with stage of disease could not be established. The low values were associated with decreased T-cell numbers and significantly increased monocyte levels. The fact that those values were significantly lower than have been reported previously for cancer patients was discussed as was the identity of the cells that previously had been counted as B-lymphocytes.

B-Lymphocytes↗
PubMedDate not supplied

Heterotopic ossification: are range of motion exercises contraindicated?

The incidence, time of onset, and role of exercise in the progression of heterotopic ossification were documented retrospectively in burn patients. In 12 of 1,066 patients (1.2%) consecutively admitted to a burn center, the abnormal bone formed posteriorly around the elbow joint. The initial signs were localized joint pain and rapid decrease in range of motion, and the average time of onset was 12 weeks after thermal injury. Prior to the diagnosis of heterotopic ossification, all patients were managed with an exercise program of active and active-assisted movements. In patients who persisted with passive and active-assisted range of motion, especially beyond the range of pain-free movements, the ossification progressed to complete ankylosis and required surgical intervention to remove the heterotopic bone. On the other hand, postoperative patients and patients who followed a program of active exercise within the pain-free range gained excellent range of motion. It was concluded that passive stretching of the periarticular structures during the acute phase of heterotopic bone formation is detrimental to the final outcome.

Adult↗
PubMedDate not supplied

Consideration of physical parameters to predict thermal necrosis in acrylic cement implants at the site of giant cell tumors of bone.

In the previous paper we had developed a general thermodynamic equation describing a polymethylmethacrylate implant at the site of giant cell tumors. In this paper we consider various characteristics of bone and methylmethacrylate crucial to the analysis such as thermal conductivity, specific heat, density, and heat generation. Also, an estimation of the temperature at which adjacent cells die is analyzed from literature. Finally, using the physical constants measured in laboratory situations a temperature profile is developed at various depths of bone that could facilitate predicting the zone of necrosis. These analyses show the maximum temperature attained in the acrylic cement-bone system depends primarily on the volume of the implant, the relative proportion of polymerization of the monomer, the temperature at which the monomer and polymer are mixed together, and the time lapse between the beginning of polymerization and implantation into the bone cavity. The temperature profile is shown to be relatively insensitive to the geometry of the system, greatly simplifying the analysis.

Bone Cements↗
PubMedDate not supplied

Thermodynamic considerations of acrylic cement implant at the site of giant cell tumors of the bone.

A discussion of the thermodynamic aspects of a relatively new treatment method for giant cell tumors of the bone is presented in this paper. The advantages of implanting methylmethacrylate acrylic bone cement into a curetted tumor site are briefly discussed and placed in perspective relative to more prevalent surgical treatments. As the bone cement self-heats while curing, the possibility of heat necrosis in the bone exists. However, the damage due to heat may be beneficial in reducing the rate of tumor recurrence. A thermodynamic consideration of the treatment situation appears to be warranted. After a general introduction and a brief literature review, the theoretical thermodynamic equations are developed. Once the basic equations for the heat transfer from the cement or the bone are derived, there is then a discussion of the various characteristics of bone and methylmethacrylate crucial to the analysis, such as, thermal conductivity, specific heat, density, and heat generation parameters. Finally, in order to reduce the theory to a form which may be used practically, the equations derived are written in terms of finite-difference equations, which approximate them numerically. Different equations are written for each type of heat transfer condition encountered in the cement-bone system as spacial variances in material and geometry occur. The equations derived may be used to model the system allowing one to predict the time-dependent temperature distribution in bone during the curing of acrylic cement. Using computer techniques to reduce the equations obtained from this analysis, and knowing the temperature at which adjacent cells die, a zone of necrosis may be mapped surrounding the acrylic impact.

Bone Neoplasms↗