Biomedical subjects

R R Richards

Publications and source records attributed to R R Richards.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Influence of the number of cortices on the stiffness of plate fixation of diaphyseal fractures.

OBJECTIVE: To determine the influence of the number of cortices of fixation on the stiffness of plate fixation of diaphyseal fractures. DESIGN: Canine experimental study. SETTING: Tertiary referral and teaching hospital in Toronto, Canada. PARTICIPANTS: Paired radii from fourteen skeletally mature, cross-bred dogs. MAIN OUTCOME MEASURE: One member of each pair of radii was tested intact as a control, and the other had a transverse osteotomy plated sequentially with five to ten cortices of fixation on either side of the simulated fracture. Dynamic compression plates and limited contact dynamic compression plates were used in two groups with seven paired radii each. Normalized torsional stiffness and four-point bending stiffness were determined in the elastic range for the control and each of the plated constructs in both groups, using a materials testing machine. RESULTS: The authors found no significant difference between the stiffness of the dynamic compression plates and limited contact dynamic compression plates. With either plate of a given length, significantly increased torsional stiffness is achieved with end bicortical screws. For bending stability with the plate at right angles to the bending plane, even short plated constructs have a stiffness exceeding that of intact bone. CONCLUSIONS: For a transverse osteotomy with no fracture interdigitation, the bending rigidity with the plate at right angles to the bending plane is greater than the original stiffness of the bone for all constructs tested, with the exception of the limited contact dynamic compression plate with five cortices of fixation. The torsional rigidity of fixation only approaches the original rigidity of the bone for ten cortices of fixation with the dynamic compression plate and the limited contact dynamic compression plate.

Animals↗

PubMedDate not supplied

Injury to the brachial plexus during Putti-Platt and Bristow procedures. A report of eight cases.

Eight patients with documented recurrent anterior dislocation of the shoulder sustained iatrogenic brachial plexus injuries during either Putti-Platt or Bristow procedures. Two patients also sustained axillary artery injuries. There were six males and two females. Postoperatively, complete paralysis of the musculocutaneous nerve was noted in six cases and incomplete paralysis in one case. Two patients had complete axillary nerve palsies. There were two cases of partial paralysis of the radial, median, and ulnar nerves, respectively. Seven of the patients underwent brachial plexus exploration an average of 16 weeks following their initial operation (range, 4 to 40). Suture material was removed from around or within two musculocutaneous nerves and one ulnar, one median, and one axillary nerve. Two lacerated musculocutaneous nerves were amenable to delayed primary repair. Two musculocutaneous, one median and one axillary nerve required grafting. Injury to the brachial plexus was associated with inadequate knowledge of regional anatomy, blind clamping of axillary artery lacerations, use of axillary incisions which limited exposure, and failure to identify the musculocutaneous nerve during Bristow procedures. If a brachial plexus injury occurs during a Putti-Platt or a Bristow procedure and the lesion does not rapidly, progressively, and completely recover, the brachial plexus should be explored since there is a high likelihood of structural neurologic injury.

Adolescent↗

PubMedDate not supplied

Some social factors related to control of diabetes mellitus in adult Jamaican patients.

A population of 103 adult diabetic patients was interviewed at the Outpatient Clinic for diabetic patients of the University Hospital of the West Indies to examine the effects of severity of the illness and social variables, such as facilities at home, education attained, employment status, informal medication, and understanding of the illness in relation to its control. Patients were classified as severe if there were clinical evidence of vascular or neurologic complications of diabetes and as mild if there were no complications. Control of diabetes was regarded as good if the patients were free from or had less than 2+ glycosuria and as poor if they had had 2+ or more glycosuria during the six months before the study. We found that the quality of control was mainly determined by the severity of the disease. In the mild diabetic, proper diabetic control was not influenced by any social variable examined. In the severe diabetic the quality of control was associated with social amenities, educational status, employment status, and understanding of the disease.

Adult↗