The effect of distraction rate on bone histological and histomorphometrical properties in an ovine mandible model

Lengthening the mandible by distraction osteogenesis (DO) is nowadays a well-recognized technique in maxillofacial surgery. This study compared two different distraction rates and evaluated histological and histomorphometrical properties of the distracted bone in an experimental ovine mandible model with the goal of elaborating a universally accepted distraction protocol.

STUDY DESIGN

Tissue blocks of regenerated bone were harvested from twelve young adult sheep. DO was performed on the mandibular midline after five days of latency period. The sheep were divided into two groups. The first group underwent activation of 0.8 mm÷day during 12 days resulting in 9.6 mm of new bone while the second group followed a geometric rate pattern of 0.2 mm - three days, 0.4 mm - three days, 0.8 mm - three days and 1.6 mm - three days resulting in 9 mm of new bone. The regenerated bone was histologically and histomorphometrically analyzed after 30, 45 and 60 days of consolidation. The relative osteoid volume (OV÷TTV) was significantly increased in the geometric rate distraction group (p=0.015) comparing with linear distraction group while the relative bone volume (BV÷TTV) was significantly increased in the linear distraction group (p=0.019) compared to the geometric distraction group.

Improved limits on nu(e) emission from mu+ decay

We investigated mu(+) decays at rest produced at the ISIS beam stop target. Lepton flavor (LF) conservation has been tested by searching for nu(e) via the detection reaction p(nu(e),e(+))n. No nu(e) signal from LF violating mu(+) decays was identified. We extract upper limits of the branching ratio (BR) for the LF violating decay mu(+)-->e(+)+nu(e)+nu(-) compared to the standard model (SM) mu(+)-->e(+)+nu(e)+nu(mu) decay: BR<0.9(1.7) x 10(-3) (90% C.L.) depending on the spectral distribution of nu(e) characterized by the Michel parameter rho=0.75(0.0). These results improve earlier limits by one order of magnitude and restrict extensions of the SM in which nu(e) emission from mu(+) decay is allowed with considerable strength. The decay mu(+)-->e(+)+nu(e)+nu(mu) often proposed as a potential source for the nu(e) signal observed in the LSND experiment can be excluded.

Vertical distraction of a free vascularized fibula flap in a reconstructed hemimandible: case report

The authors report a case of vertical distraction osteogenesis of a free revascularized fibula flap used to reconstruct an hemimandible lost as a result of a gunshot injury. The reconstruction procedure and the distraction protocol are described; clinical and radiological results are presented. The vertical discrepancy between the fibula and the native right hemimandible was corrected.