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Biomedical subjects

M R Tucker

Publications and source records attributed to M R Tucker.

At least 37 records · Page 2Linked to original sources
PubMed1989

Conscious sedation.

Explore the source record for details and available documents.

Anesthesia, Dental↗
PubMed1989

Internal screw fixation: comparison of placement pattern and rigidity.

Multiple screw placement patterns and techniques have been described for fixation of the sagittal split ramus osteotomy. This study evaluated transverse strength (rigidity) of six groups of simulated sagittal osteotomies fixed with different screw patterns and placement techniques. Osteotomies fixed with screws placed in an inverted L pattern were significantly more rigid than those fixed with screws placed in a linear pattern or K-wires placed in a triangular pattern (P less than .05). No significant difference in rigidity was noted between compression and bicortical screws placed in identical patterns.

Animals↗
PubMed1989

Stress shielding effect of rigid internal fixation plates on mandibular bone grafts. A photon absorption densitometry and quantitative computerized tomographic evaluation.

The use of rigid internal fixation reconstruction plates in combination with bone grafts provides many advantages in mandibular reconstruction. These advantages include ease of adaptability at the time of surgery as well as immediate postoperative function for the patient. Disadvantages may include a "stress shielding" or disuse osteoporosis effect on the underlying bone graft as a result of the rigidity of the reconstruction plate. This study evaluated the stress shielding effects on bone grafts in primate mandibles. Bilateral bone grafts stabilized with rigid fixation plates were performed in 4 Macaca fascicularis monkeys. Three months after the bone grafting procedure one plate was removed from each monkey. The monkeys were then killed 1, 4, 6 and 8 months after plate removal. Photon absorption densitometry and computerized tomography were used to evaluate stress shielding. The results of this study indicate that the stress shielding effect occurs if the plate is not removed from the area of bone grafting postoperatively.

Absorptiometry, Photon↗
PubMed1989

Histomorphometric evaluation of stress shielding in mandibular continuity defects treated with rigid fixation plates and bone grafts.

Histomorphometric techniques were used to evaluate the stress shielding effect in bilateral bone grafts in 4 Macaca fascicularis monkeys. Bilateral continuity defects were created and grafted by replacing the resected portion of the mandible and iliac crest bone into the defect area. Both sides were plated with rigid internal fixation plates. Three months after bone grafting, the plate was removed from one side while the other plate was left in place. The animals were sacrificed at 1, 4, 6, and 8 months after plate removal and the grafted areas removed for histomorphometric analysis. This study documents decreased bone volume as well as smaller interlabel width on the plated side, suggesting a stress shielding effect as a result of the rigid internal fixation plate.

Animals↗
PubMed1989

Complications of orthognathic surgery: a comparison between wire fixation and rigid internal fixation.

This retrospective review compares the results of using rigid internal fixation (RIF) and wire fixation for orthognathic surgery patients. The records of two groups of demographically similar patients who underwent comparable surgery, performed by the same four attending surgeons at the same institutions during the same time period (1983 to 1986), were evaluated for complications and unanticipated treatment results. The most striking finding of this study is the general similarity between the two groups. However, differences in frequency of excessive weight loss and persistent restriction of mandibular opening suggest a benefit from early mobility of the mandible that comes with RIF. Because there was no concomitant increase in complications or unexpected results of treatment, the introduction of RIF for orthognathic surgery may offer patients some potential advantages.

Humans↗
PubMed1986

Autogenous dermal grafts for repair of temporomandibular joint disc perforations.

In five Macaca fascicularis monkeys bilateral 5-mm perforations of the intra-articular disc were followed by unilateral repair with autogenous dermal grafts. The monkeys were killed at three, six, 12, 24, and 36 weeks after surgery. The temporomandibular joints (TMJs) were removed en bloc, decalcified, and sectioned in the sagittal plane for histologic examination. All of the control untreated disc perforations, with the exception of one, failed to heal. With all of the grafted disc perforations, viable dermis and fibrous connective tissue proliferation were seen in the area of the repaired perforation. Therefore, autogenous dermal grafting appears to be an acceptable technique for repair of the damaged disc in degenerative joint disease of the TMJ.

Animals↗
PubMed1986

Versatility of CT scanning for evaluation of mandibular hypomobilities.

The use of CT scanning serves as an excellent radiographic method for evaluating mandibular hypomobilities. A clear resolution of bony, as well as soft tissue components of all structures associated with temporomandibular joint and coronoid process areas provides the best radiographic image. Several cases illustrating the use of computerized tomography are presented.

Adolescent↗
PubMed1986

A comparison of amnesia in outpatients sedated with midazolam or diazepam alone or in combination with fentanyl during oral surgery.

Midazolam is a new, water-soluble benzodiazepine that has been reported to produce a greater degree of amnesia than does diazepam. This study compares the amnesia produced in patients sedated with midazolam or diazepam or in combination with fentanyl during oral surgery. Twenty-four hours after surgery, each patient answered a questionnaire designed to assess his or her recall of events during and after surgery. Patients who received midazolam alone recalled significantly less than did patients in either diazepam group. The addition of fentanyl to midazolam did not produce any significant difference in recall.

Anesthesia, Dental↗
PubMed1986

Arterial blood gas levels after midazolam or diazepam administered with or without fentanyl as an intravenous sedative for outpatient surgical procedures.

The purpose of this study was to compare arterial blood gas measurements made during the baseline, initial sedation, maintenance, and recovery periods in patients sedated with midazolam and saline (MS), midazolam and fentanyl (MF), diazepam and saline (DS), and diazepam and fentanyl (DF). During induction both the MF and the DF groups had significantly lower average PO2, pH, and O2 saturations and significantly higher PCO2 values than either the MS or the DS group. While the differences were not as great, the same was also true during the maintenance phase of the procedure. During recovery, patients receiving MF had lower average PO2, pH, and O2 saturation and higher PCO2 values than the MS or the DF group. Patients receiving MF had significantly lower average PO2, pH, and O2 saturation levels and significantly higher average PCO2 levels during all three postsurgical periods than at baseline. Patients receiving DF had significantly lower average PO2, pH, and O2 saturation levels and significantly higher Pco2 levels during both induction and maintenance than at baseline.

Ambulatory Surgical Procedures↗
PubMed1984

Coronoid process hyperplasia causing restricted opening and facial asymmetry.

A case of coronoid process hyperplasia is presented. The primary presenting complaint and clinical feature was restriction of opening, although there was marked facial asymmetry in the area of the right zygoma. Presurgical documentation of this anatomic variation by routine radiography and computed tomography with sagittal reconstruction is presented.

Adolescent↗
PubMed1984

Subanesthetic doses of ketamine, diazepam, and nitrous oxide for adult outpatient sedation.

The use of ketamine in adults has been complicated by untoward hallucinatory emergence reactions. The addition of nitrous oxide and diazepam to subanesthetic doses of ketamine may be effective in decreasing these reactions. Adult patients were sedated for outpatient oral and maxillofacial surgery procedures using nitrous oxide, diazepam, and either fentanyl or ketamine. Postoperative questionnaires were used to evaluate hallucinatory reactions, amnesia, and patient acceptance. Comparison of the results of patients receiving ketamine and those receiving fentanyl revealed no statistical differences in hallucinatory reactions or patient acceptance. Amnesia was more complete in the ketamine than the fentanyl group.

Adolescent↗