Comparisons of bone volumes and densities relating to osseointegrated implants in microvascularly reconstructed mandibles: a study of cadaveric radius and fibula bones.

The study was designed to compare the dimensions and densities of two frequently used bone donor sites with regard to placement of endosseous dental implants in microvascularly reconstructed mandibles. A total of 40 radii and of 40 fibulae were investigated. Fifty two percent of the fibulae had adequate bone volume for the positioning of four 10 mm implants, while this figure was 55% for the radii. After using the 'double barrel' technique the placement of four 10 mm implants succeeded in 87% of all the fibulae. Due to the lack of bone length required, this special technique was not possible in the radii investigated. Cortical thickness and density of bone were higher in the radii when compared with the fibulae. In each bone the central and distal parts presented the highest values of cortical thickness and density. Although the radius offers enough substantial bone for implant placement in some cases this cannot be used for clinical purpose, as only hemicortical grafts can be obtained. Otherwise the resulting donor site morbidity would be intolerable. In conclusion, our results support the clinical experience that the fibula is today's 'work horse' donor site for reconstruction of the mandible.

Effects of intravenous erythromycin on antroduodenal motility in humans: non-invasive observations with real-time ultrasound.

Erythromycin has been shown to act on motilin receptors on gastrointestinal smooth muscle in vitro and to accelerate gastric emptying in normal subjects as well as in patients with diabetic mellitus. To evaluate the motor pattern that accounts for this accelerated emptying, the effects of 12.5 mg/min erythromycin vs. placebo on postprandial motility of the antroduodenum was examined with real-time ultrasound in 15 normal subjects. During 10 minutes of observation, erythromycin significantly increased forward transpyloric flow episode (1.04 +/- 0.19 vs. 0.37 +/- 0.41; p < 0.05), forward transpyloric flow duration (5.79 < 4.49 vs. 3.19 < 1.72 seconds; p < 0.05) and improved antro-pyloro-duodenal coordination (0.43 +/- 0.23 vs. 0.21 +/- 0.17; p < 0.05). However, no significant differences were found for gastric peristaltic cycle (22.62 +/- 3.06 vs. 23.40 +/- 2.14 seconds; p > 0.05), retrograde transpyloric flow episode (0.13 +/- 0.16 vs. 0.18 +/- 0.29; p > 0.05), and retrograde transpyloric flow duration (1.24 +/- 0.30 vs. 1.38 +/- 0.58 seconds; p > 0.05). We conclude that erythromycin increases episode and duration of forward transpyloric flow, and improves antro-pyloro-duodenal coordination, which may play a role in accelerating gastric emptying.

Use of real-time ultrasound for detection of gastric motility.

BACKGROUND: To evaluate the clinical applications and reproducibility of real-time ultrasound in detecting gastric motility, result of study of gastric motility in normal volunteers is reported. METHODS: From January to May 1994, 21 normal volunteers, with a mean age of 31.7 years, 10 females and 11 males, entered this study. They fasted overnight. After consuming a liquid test meal (500 cc, 80.627 Kcal, containing sieved bran particles), they received real-time ultrasound examinations immediately to detect gastric peristalsis and transpyloric fluid flow. To evaluate the reproducibility of real-time ultrasound methods in gastric motility, four of the volunteers repeated this examination at an interval of one week. RESULTS: The results showed that the mean gastric peristaltic cycle in humans is 24.29 seconds (s); mean forward transpyloric flow duration is 4.00 s; mean retrograde transpyloric flow duration is 1.45 s and mean time needed for initiating gastric peristaltic contractions after the test meal is 138.06 s. Age, body weight and body surface have a positive correlation to the mean gastric peristaltic cycle. Females, with a less body weight and body surface than males, exhibit a faster gastric peristaltic cycle. Real-time ultrasound is a reproducible method for studying gastric motility. CONCLUSIONS: Real-time ultrasound is an inexpensive, reproducible and practical method for studying gastric motility. In addition, age, body weight and body surface have a positive correlation to gastric peristaltic cycle, with females, whose body weight and body surface are less than males, showing a shorter gastric peristaltic cycle.