Biomedical subjects
Publications and source records attributed to R J Friedman.
Multiple factors appear to influence survival of patients with MM. As computer and mathematic analysis techniques advance, the specific effects of these variables, in terms of their impact on survival rates, will be delineated better.
There are many clinical and histologic factors that are known to be valuable in predicting survival rates for patients with cutaneous malignant melanomas. Breslow thickness is considered to be the most reliable prognostic factor; however, thickness is a unidimensional measurement. A more accurate mensuration to predict biologic behavior might be one that takes into account the three-dimensional volume of the neoplasm. In a study of 35 primary malignant melanomas, the volumes of the dermal components of the tumors were calculated. Those patients with tumor volumes of 200 mm3 or less had a 91.4% 5-year disease-free survival rate, compared with survival rate of only 16.7% for those patients whose lesions had tumor volumes exceeding 200 mm3. On multivariate analysis, tumor volume exceeded thickness as a prognostic indicator. Thus, measurement of tumor volume proved to be of greater significance than thickness in predicting the outcome for patients with malignant melanomas.
A silver staining technique has recently been devised to aid in the differentiation between benign and malignant melanocytic lesions. This study showed a statistically significant difference between the staining of silver-nucleolar organizer regions (AgNORs) in melanocytic nevi and that of AgNORs in malignant melanomas.
Recent advances in computer technology have begun to make computers a more effective tool in the diagnosis and evaluation of malignant melanoma. Preliminary computer-aided diagnosis programs have been developed. Histologic evaluation applications in both diagnosis and prognosis are also evolving. Further advances in computers may make them an integral part of the diagnosis and prognosis of melanoma in the future.
A total of 452 patients with dysplastic nevi (DN) were followed prospectively by repetitive, complete cutaneous examinations in order to determine the clinical features of early malignant melanomas (MM) arising in them. Sixteen patients (3.5%) developed 18 newly diagnosed MM during an average follow-up period of 27 months. Twelve of the 18 MM were in situ and all of the primary invasive MM diagnosed prospectively in this follow-up were less than 0.89 mm in Breslow thickness, implying an excellent prognosis. The principal clinical clue to the diagnosis of MM was change in a preexisting pigmented lesion. Total-body photographs were very useful in helping to identify the early MM in these patients.
Fourteen patients were retrospectively reviewed to examine the role of arthroscopy in the diagnosis and treatment of the problem total knee arthroplasty (TKA), and to define parameters for indications, techniques, and results. All patients had undergone a previous TKA, and postoperatively had problems with pain and/or range of motion. Routine evaluation failed to reveal sepsis or aseptic loosening. Arthroscopy was used to evaluate and treat certain specific conditions. The arthroscope was successful in removing loose bodies, correcting patella subluxation with an arthroscopic lateral release, excising a symptomatic pseudomeniscus, and releasing intraarticular adhesions to improve motion and relieve pain. The postoperative knee score improved 73%. Arthroscopy is a valuable tool to evaluate a painful TKA, and can be used to treat certain conditions that would otherwise require an arthrotomy. The rehabilitation time is easier on the patient and much quicker. Arthroscopy of a TKA does not compromise any future procedures. However, it remains a technically demanding procedure whose indications and expectations are still being defined.
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The use of electrical stimulation in fracture management is increasing. Electrical stimulation has been found to offer a reasonable means of treatment for nonunions that have failed to respond to previous bone grafting over an extended period of time. The effective use of electrical stimulation devices requires an understanding of the various principles and concepts employed by the four types of stimulators currently available. While the exact mechanism of electrically-induced osteogenesis is uncertain, current theories indicate that several factors probably are involved and more than one mechanism may be responsible. There are significant differences in the clinical applications of the various types of electrical stimulators. Whether these differences are significant from a practical standpoint remains to be seen.
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Twenty-four patients receiving total knee arthroplasty (TKA) were randomized into one of three groups based on tourniquet inflation one, two, or five minutes after administration 1 g cefazolin. Simultaneous serum, soft-tissue, and bone samples were obtained at regular intervals during surgery. All soft-tissue and bone samples were corrected for cefazolin content. The percentage of cefazolin penetration into soft tissue and bone was calculated using the area under the concentration time curve. Adequate cefazolin concentrations for soft tissue and bone were defined as greater than or equal to 4 x minimum inhibitory concentration90 (MIC90 = 1 microgram/ml) of cefazolin to Staphylococcus aureus and coagulase-negative staphylococci. Patients were similar in age, actual body weight, creatinine clearance, and length of tourniquet inflation. The median percentage of cefazolin penetration into soft tissue and bone for the five-, two-, and one-minute groups was 14.5% and 4.6%, 6.7% and 3.0%, and 5.9% and 4.6%, respectively; the percentage of penetration into soft tissue between the five- and one-minute groups was statistically significant. A higher percentage of patients achieved the desired cefazolin concentration (greater than or equal to 4 micrograms/g) if a five-minute interval was selected. The five-minute group achieved the highest mean ratios of concentration to MIC compared with the two- and one-minute groups, although the differences were not statistically significant. The standard 1 g of cefazolin with a five-minute interval between administration and tourniquet inflation resulted in adequate mean soft-tissue and bone concentrations for prophylaxis during TKA with a tourniquet time less than two hours. Additional doses are not warranted after tourniquet release.
Patients undergoing total knee arthroplasty were randomized to tourniquet inflation 1, 2, or 5 minutes after a 1-g dose of cefazolin. Serum, soft tissue, and bone samples were obtained at 10, 30, and 60 minutes after inflation, immediately prior to tourniquet release (PTR), and 5 minutes after release. Areas under the concentration-time curve (AUC10-PTR) were calculated using the linear trapezoidal method and normalized to actual body weight, creatinine clearance, and length of tourniquet inflation. The percentage of penetration was calculated using the normalized values for the respective AUCs. Differences among the groups were analyzed using analysis of variance or the Kruskal-Wallis test where appropriate. Groups were similar for age, actual body weight, duration of tourniquet inflation, and creatinine clearance (p greater than 0.05). The median percentages of penetration for soft tissue and bone at 5, 2, and 1 minute were 14.5% and 4.6%, 6.7% and 3.0%, and 5.9% and 4.6%, respectively. Only the percentage of soft tissue penetration between 5 and 1 minute was significantly different (p = 0.015). Gender and type of anesthesia (general, epidural) had no effect on cefazolin penetration into soft tissue or bone. Although increasing the time interval between cefazolin administration and tourniquet inflation resulted in higher soft tissue drug concentrations, a 1-minute interval resulted in soft tissue and bone cefazolin concentrations at or above the minimum inhibitory concentration for microorganisms likely to be encountered in this surgical procedure.
One hundred thirty-seven revision total knee arthroplasties (TKA) performed in 117 patients with failed aseptic metal-to-plastic knees over ten years (1974-1984) were studied to determine the long-term clinical and roentgenographic results and were compared to primary TKA. The mean age was 65 years (range, 32-90 years). Fifty-three percent had rheumatoid arthritis, and 47% had osteoarthritis. The mean interval from initial to revision TKA (129 knees) was four years (range, three months to 11 years) and from the first to second revision (seven knees) was 2.4 years (range, seven months to 5.5 years). The most common reasons for failure were loosening (73%), patellar complications (13%), and instability (10%). The mean follow-up time was 5.2 years (range, two to 12 years). Function, instability, motion, and pain all improved after revision TKA, but these improvements were significantly less than those seen after primary TKA. One-third of the patients still ambulated with crutches, a walker, or not at all. While mean postoperative flexion was 100 degrees, 24% could not flex to 90 degrees. Most patients (90%) were malaligned at the time of failure and remained so after revision (78%). The increased incidence of radiolucent lines (tibial, 61%; femoral, 24%) was not related to increased failure. Complications were not increased over primary TKA. The failure rate was 5.8% at 5.2 years, or approximately 1% per year. A successful clinical result was defined as a knee with mild or no pain, mild or no instability, and flexion to at least 90 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)
A total of 452 white patients, classified into four dysplastic nevi groups, were followed prospectively by repetitive, complete cutaneous examinations using total-body photographs taken on entry into the study. Sixteen patients (3.5%) developed 18 newly diagnosed malignant melanomas (MM) during an average follow-up period of 27 months. Twelve of the 18 MM were in situ, and all of the six primary invasive MM diagnosed prospectively in this follow-up were less than 0.89 mm in Breslow thickness, implying an excellent prognosis. Compared with reference populations, the number of MM detected significantly exceeded the number estimated to occur in the comparable age-matched control groups. These data support the concept of repetitive follow-ups of all groups of patients with dysplastic nevi.
Micromotions at the interface between bone and prosthesis are believed to induce bone resorption and ultimately lead to loosening of the implant. Thus the initial stability achieved by a hip prosthesis is an important factor for the long-term function of the implant. Knowing the biological consequences of the mechanical conditions, it appears to be mandatory to measure the extent of these three-dimensional movements. An in vitro dynamic method for measurement of the micromotion of the femoral component of hip prostheses has been developed. Tests in cemented prostheses have confirmed that the use of cement reduces sinkage and rotation manyfold and have yielded reference values for stability. Comparison with two types of cementless prostheses has shown that certain cementless implants may achieve stability comparable to cemented ones in some load directions.
Twenty-four nonconstrained total elbow arthroplasties (TEAs) in 20 patients with severe disabling functional class IV rheumatoid arthritis were reviewed retrospectively to determine the effects of their disease on the end result. The mean follow-up period was 6 years (range, 2-11 years). All planes of elbow motion improved after surgery (P less than .005), there was a highly significant reduction in pain and improvement in function (both P less than .005) and patient satisfaction was high. The severity of the disease does not appear to affect the end result when a nonconstrained TEA is used, and the results compare favorably with those of other series reported.
A case of ipsilateral distal clavicle fracture and sternoclavicular joint dislocation is reported. This combination of injuries results from two separate forces in sequence. Closed reduction of the dislocation was possible only after open reduction and internal fixation of the clavicle fracture was performed, because of the inability to manipulate the free-floating segment. Patients should be carefully examined for associated brachial plexus injuries.
Lower eyelid retraction may be due to vertical deficiency of the anterior lamella, supporting cartilage, or posterior lamella. We have used autologous cartilage grafts from the conchal bowl for reconstruction of the central lamella, reestablishing and augmenting support of the lower lid. The positioning of the graft is dependent on the specific anatomic deficiency, and the etiology of the lid retraction must be carefully evaluated. In patients with posterior lamella deficiency, the contracted lower lid retractors and conjunctiva are released and the graft is placed facing the bulbar conjunctiva and is allowed to reepithelialize. In patients in whom there is an associated skin deficiency, composite auricular grafts are used. We present our experience in 33 patients with lower lid retraction. Twenty-three patients required placement of a cartilage graft only, while 10 patients had an associated skin deficiency requiring placement of composite cartilage. In nine patients the cartilage graft was seated against the bulbar conjunctiva and allowed to reepithelialize. Reepithelialization was complete within 3 1/2 weeks in all but two of these patients. This technique has provided stable lid support in all 33 patients.