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Biomedical subjects

M K Benson

Publications and source records attributed to M K Benson.

84 records · Page 5Linked to original sources

Abnormal chemoreceptor response to hypoxia in patients with tabes dorsalis.

Nine patients with tabes dorsalis and one patient with diabetic autonomic neuropathy were subjected to hypoxia to test the integrity of their carotid chemoreceptors. Ventilation and pulse rate changes were monitored and compared with those of a group of normal subjects of comparable age and sex. Four patients had a completely negative response to hypoxia, and the changes in ventilation in the group of patients as a whole were significantly less than in the control subjects. The results indicate that some patients with autonomic denervation are unable to adjust their respiratory system in response to hypoxia.

Aged↗

Progressive osseous heteroplasia: a case report.

We report the case of a young female who, from infancy, suffered extensive, progressive, heterotopic ossification of her left lower limb. Heterotopic ossification, which was largely but not exclusively intramembranous in type, was most marked in subcutaneous fat but was also noted in muscle and deep connective tissue. The spectrum of changes noted suggests that this congenital disorder of soft tissues is similar to that recently described as progressive osseous heteroplasia.

Abdomen↗

Heel seats and shoe wear.

Seventy-two children with excessive heel valgus and markedly uneven shoe wear were treated by Helfet heel seats for 18-36 months. Of the 52 children reviewed in this study, 44 had improved shoe wear. Simple heel seats offer economical treatment for children whose foot deformities destroy their shoes.

Child↗

Errors in measurement of acetabular index.

Errors in determining the acetabular index can be induced either by incorrectly positioning the child for radiographs or by inter- or intraobserver errors. From postmortem radiographic studies, we have determined the magnitude of these errors. The error caused by pelvic rotation is +/- 3 degrees if the obturator foramina ratio is kept within 0.5 to 2. If pelvic flexion/extension is confined to +/- 10 degrees, the error induced by flexion/extension is +/- 3 degrees. The intraobserver error was +/- 2 degrees, and the interobserver error was +/- 3 degrees. Under these circumstances, the total error is +/- 5 degrees. We have not been able to find a satisfactory way of limiting the flexion/extension to +/- 10 degrees. In some circumstances, particularly if a child is distressed, the flexion/extension may be 20 degrees from neutral; under these circumstances, errors as large as 10 degrees can occur. Surgeons should be aware that very large errors can occur when the acetabular index is measured.

Acetabulum↗

Does early treatment by abduction splintage improve the development of dysplastic but stable neonatal hips?

A prospective trial was carried out to assess the outcome of children aged from 2 to 6 weeks with stable but dysplastic hips, treated with abduction splintage or by observation. Forty-four patients with 63 dysplastic hips were entered into the study and allocated into the two treatment groups at random. The ultrasound measured percentage acetabular cover in the splinted group improved in the first 3 months from an average of 32.8 to 54.3%. In the unsplinted group, the increase in cover was from 36.7 to 48.6%. The changes in cover for the splinted group were significantly more than those for the unsplinted group (p < 0.003) There was, however, no significant difference between the two groups in acetabular angle measurements on plain radiographs taken at 3 months. At 24 months, similarly, there was no significant difference in the acetabular angles of the two groups. These results support the view that stable dysplastic hips will correct with growth and that there is no sustained benefit from early splintage.

Female↗

Phrenic nerve and diaphragm function following open heart surgery: a prospective study with and without topical hypothermia.

In a prospective study, 100 patients undergoing open heart surgery were randomly allocated to receive ice/slush topical hypothermia for myocardial protection (Group I, n = 56) or not (Group II, n = 44). Chest radiographs, diaphragm screening, lung function and phrenic nerve conduction time were assessed pre-operatively and at 1 week and 1 month post-operatively in all patients and subsequently at 3 months, 6 months, 1 year and 2 years in all patients with radiological evidence of diaphragm paralysis. The two groups were similar in terms of age, sex, diabetes and smoking habits. Cardiopulmonary bypass and aortic cross-clamp times were similar in the two groups. Radiological evidence of partial left lower lobe collapse was more frequent in Group I (79 per cent vs. 36 per cent, p < 0.01). Twenty (36 per cent) Group I patients developed unilateral diaphragm paralysis (19 left-sided) compared with none in Group II. Diaphragm paralysis was still present in 19 patients (34 per cent) at 1 month, in five patients (9 per cent) at 1 year and in one patient (2 per cent) at 2 years post-operatively. Phrenic nerve conduction time was recorded in 98 per cent of patients pre-operatively, but was unrecordable on the appropriate side in all 20 patients with diaphragm paralysis 1 week post-operatively. Prolonged phrenic nerve conduction time on the left side was found in a further seven Group I patients 1 week post-operatively. There were no significant differences between the two groups in terms of post-operative arrhythmias, myocardial infarction or mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Clubfoot: its pathological anatomy.

The pathologic anatomy of clubfoot is complex, and the opportunities to examine neonatal specimens are inevitably rare. Three clubfeet were dissected and compared with a normal foot. The shape, orientation, and alignment of the bones were gauged, and tibial torsion was measured. Particular attention was paid to the "medial tie," and its etiologic role was considered.

Calcaneus↗