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Biomedical subjects

D F Bell

Publications and source records attributed to D F Bell.

At least 19 recordsLinked to original sources
PubMed1992

Pediatric applications of the Ilizarov method.

Since mid-1987, more than 250 applications of the Ilizarov technique have been successful in treating a variety of pediatric orthopedic problems. The principles of the method are the same in adults and children. Careful preoperative planning and close follow-up evaluation during distraction are important to success. Complication rates are high but improving as experience is gained with the technique. Most complications can be managed such that the ultimate success is not jeopardized. The Ilizarov technique has wide application in the treatment of difficult deformities. The method is useful for treatment of limb-length discrepancy projected to be greater than 5 cm and in limb-length discrepancy combined with angular deformity. The method is applicable to angular deformities such as in adolescent Blount's disease and congenital tibial pseudarthrosis, especially conditions where bone transport may be needed to gain length. In resistant or recurrent clubfeet, the Ilizarov technique is useful as an alternative to osteotomy of the mid- and hindfoot or both. The method may even be indicated for lengthening limbs in selected patients with short stature.

Adolescent↗
PubMed1991

Problems with substantial limb lengthening.

Limb lengthening takes careful planning and meticulous outpatient care and still is burdened by minor complications. Experience may lessen major complications, but pin tract problems, swelling, and pain will plague these patients. A large group of patients can benefit from lengthening procedures, and new techniques are improving the risk-benefit balance. A thoughtful approach is needed by the surgeon, especially taking time to fully inform the patient about the time, effort, and problems involved in substantial limb lengthening.

Bone Lengthening↗
PubMed1991

Posterolateral rotatory instability of the elbow.

Recurrent posterolateral rotatory instability of the elbow is an apparently undescribed clinical condition that is difficult to diagnose. We treated five patients, ranging in age from five to forty years, who had such a lesion and in whom the instability could be demonstrated only by what we call the posterolateral rotatory-instability test. This test involves supination of the forearm and application of a valgus moment and an axial compression force to the elbow while it is flexed from full extension. The elbow is reduced in full extension and must be subluxated as it is flexed in order to obtain a positive test result (a sudden reduction of the subluxation). Flexion of more than about 40 degrees produces a sudden palpable and visible reduction of the radiohumeral joint. The elbow does not subluxate without provocation. The cause for this condition, we think, is laxity of the ulnar part of the lateral collateral ligament, which allows a transient rotatory subluxation of the ulnohumeral joint and a secondary dislocation of the radiohumeral joint. The annular ligament remains intact, so the radio-ulnar joint does not dislocate. Operative repair of the lax ulnar part of the lateral collateral ligament eliminated the posterolateral rotatory instability, as revealed intraoperatively in our five patients.

Adult↗
PubMed1990

Effect of doxorubicin on local recurrence following marginal resection in the MGH-OGS murine model.

Despite the fact that preoperative chemotherapy causes substantial necrosis in the primary osteosarcoma tumor, most authorities recommend resecting these lesions with a wide margin of normal tissue to avoid local recurrence. This study evaluated the effect of systemic chemotherapy (doxorubicin) on tumor growth and histology in the MGH-OGS transplantable murine model and examined whether this drug prevents local recurrence after resection of the tumor with positive microscopic margins. The results indicate that doxorubicin caused prolonged cessation of tumor growth, produced substantial necrosis within the lesion, and decreased the risk of local relapse following marginal surgery. The drug effect was dose-dependent and drug efficacy in preventing local relapse was maximal with administration prior to or at the time of surgery.

Animals↗
PubMed1990

Structural abnormality of the clavicle associated with Sprengel's deformity. A case report.

Sprengel's deformity is the most common congenital anomaly of the shoulder girdle and is often accompanied by the presence of an omovertebral bone. Preoperative oblique roentgenograms or computed tomography may be necessary to define the abnormal structures in Sprengel's deformity. Sprengel's deformity in a six-year-old girl was corrected as follows. During clavicular exposure to osteotomy, an abnormal osseous bridge extending from the midportion of the clavicle to the spine of the scapula was identified and resected. A literature survey failed to identify other similar anomalies.

Child↗
PubMed1989

Growth factor production by sarcoma cells in primary culture.

Cell lines derived from human sarcomas have been previously shown to produce a protein growth factor which, similar to platelet-derived growth factor (PDGF), can induce competence for mitosis in fibroblasts. Whether this factor production is an important feature of sarcomas in vivo or simply an artefact caused by long-term culture conditions is unclear, however. We demonstrated growth factor activity in conditioned medium from six of 11 primary sarcoma cultures, utilizing flow cytometric analysis of DNA to monitor the presence of sarcoma cells in cultures. Cells isolated from control tissues failed to show a similar mitotic effect.

Cells, Cultured↗
PubMed1989

Unit rod segmental spinal instrumentation in the management of patients with progressive neuromuscular spinal deformity.

Thirty-four nonambulatory patients with progressive neuromuscular spinal deformity were surgically managed using a 1/4" U-shaped double rod construct with segmental instrumentation from T2 to the pelvis accompanied by posterior spinal fusion. Diagnoses included 17 patients with cerebral palsy, six with spinal bifida, and 11 with other diseases (spinal muscular atrophy, Friedreich's ataxia, polyneuropathy, nemaline myopathy, and polio). Twenty-three patients had single uncompensated thoracolumbar curves, and 11 had a double curve pattern. The mean preoperative major curve was 66 degrees (range, 22-132 degrees), the secondary curve 58 degrees (range, 23-84 degrees). No postoperative spinal support was used. Mean curve correction was 36 degrees or 54.6%. There were four major complications, including two implant failures requiring revision and two patients sustaining excessive intraoperative blood loss necessitating completion of the procedure in a second stage. There were two neurologic complications including one case of postoperative seizures and an L4 monoradicular neuropathy in a spina bifida patient. Four patients had temporary postoperative ileus, one gastroesophageal reflex, and four had urinary tract infections. There were no significant postoperative pulmonary complications. Excluding the patients with rod failure, mean loss of correction at mean follow-up of 21.3 months was 6.5%. The stability and curve correction obtained using this system supports its continued use in patients with progressive neuromuscular scoliosis.

Adolescent↗
PubMed1988

Timing of chemotherapy and surgery in a murine osteosarcoma model.

The sequential use of chemotherapy and surgery in the treatment of osteosarcoma developed in an empirical fashion without the benefit of investigations in animal models. The MGH-OGS murine osteosarcoma is a transplantable tumor that resembles the human disease with respect to histology, local invasiveness, metastatic characteristics, tumor ploidy, and its response to chemotherapy. We have used this tumor model to investigate the efficacy of preoperative, perioperative, and postoperative chemotherapy on the development of pulmonary metastases in three different experimental protocols. In each experimental design, perioperative chemotherapy demonstrated a significant advantage in preventing systemic relapse.

Animals↗
PubMed1988

Kinetic effects of adriamycin and bleomycin on two osteosarcoma models.

Although chemotherapeutic drugs are frequently administered to patients with osteosarcoma, there has been little research into the effect of cytotoxic drugs on osteosarcoma cell biology. The effect of two drugs (Adriamycin and bleomycin) on cell cycle kinetics was investigated in vitro in an established line of human osteosarcoma cells and in vivo using the Dunn osteosarcoma model. The cell cycle changes were consistent with G2 arrest for both drugs in vivo and in vitro. The alteration in cell cycle distribution was correlated with inhibition of 3H-thymidine incorporation in vitro. In vivo, the greater change in cell cycle distribution caused by Adriamycin was reflected in the increased inhibition of tumor growth found with this drug.

Animals↗
PubMed1988

Evaluation of fluorescein diacetate for flow cytometric determination of cell viability in orthopaedic research.

Accurate estimation of cellular viability is important both in research and in aspects of orthopaedic clinical practice. We have been interested in the potential for flow cytometric application of fluorescein diacetate (FDA) in evaluating chondrocyte survival following cryopreservation of osteochondral allografts as well as in the assessment of sarcoma necrosis following preoperative chemotherapy. In order to evaluate the suitability of this method for cell viability assays, this study compared FDA with more traditional methodology (trypan blue, clonigenic assay, metabolic activity analysis, measurement of DNA synthesis, and histological assessment of necrosis). Both chondrocytes and sarcoma cells were exposed to various experimental injuries prior to viability analysis. Although it is evident from these experiments that FDA accurately reflects cell survival after physical injury, it underestimates the effect of chemotherapy on cell reproductive potential in vitro. However, FDA is highly correlated with histological assessment of tumor viability after chemotherapy in vivo. It is apparent that the methodology chosen for determination of viability should be appropriate for the type of experimental injury and should analyze the cell function (i.e., metabolic activity or reproductive capacity) that is appropriate for the experimental model.

Animals↗
PubMed1988

Elevated partial thromboplastin time as an indicator of hemorrhagic risk in postoperative patients on warfarin prophylaxis.

Warfarin provides effective prophylaxis against postoperative venous thromboembolic complications in adults undergoing elective hip surgery, but at the risk of increased bleeding complications. Although patients on this drug are routinely monitored by prothrombin time (PT), mild elevations of the partial thromboplastin time (PTT) have been reported with warfarin therapy. In a prospective study of 194 patients undergoing elective hip surgery, the authors assessed the incidence of elevation of the PTT above 50 seconds while the patient was receiving warfarin prophylaxis and the effect of this elevation on bleeding complications. The prophylactic warfarin was begun the night prior to surgery. Thirty-eight patients (19.6%) had a PTT greater than 50 seconds (group 1) and 156 had milder or no elevation of the PTT (group 2). The mean maximum PTT in group 1 was 61.2 ( +/- 12.9), versus 39.9 ( +/- 5.0) seconds in group 2. Major postoperative bleeding complications occurred in 26.3% of group 1 patients, versus 4.5% of group 2 (P less than .01). This subset of patients with an abnormal PTT elevation despite appropriate control of the PT is at a significantly increased risk of major postoperative bleeding. This observation may also prove valuable in reducing bleeding complications from warfarin use in nonsurgical patients.

Blood Coagulation Tests↗
PubMed1988

Brace treatment for symptomatic spondylolisthesis.

The literature documents progression of spondylolisthesis, most commonly during the adolescent growth spurt. Twenty-eight patients with Grades I and II spondylolisthesis were treated with antilordotic braces. Presenting signs and symptoms included back pain (61%), tight hamstrings (53%), increased lordosis (25%), and mild scoliosis (21%). Three patients presented with spondylolysis and progressed to a slip prior to initiation of brace treatment. Mean duration of brace treatment was 25 months. In the brace, lateral roentgenograms demonstrated a significant reduction of lumbar lordosis and sacral inclination. At the conclusion of brace treatment all patients were pain-free and none had demonstrated a significant increase in slip percent.

Adolescent↗
PubMed1979

Effective evaluations.

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Education, Nursing, Continuing↗
PubMedDate not supplied

The use of the Ilizarov technique in the correction of limb deformities associated with skeletal dysplasia.

The skeletal dysplasias are a unique and heterogeneous group of disorders with skeletal manifestations including deformity, disproportion, and short stature. The purpose of this article is to describe the use of the Ilizarov technique in the management of these orthopedic problems in 15 patients with skeletal dysplasias. The technique is particularly appropriate in those patients requiring correction of angular deformity and limb lengthening. The greatest number of complications were encountered in those patients undergoing extended limb lengthening. Nevertheless, all patients achieved their preoperative goals.

Adolescent↗