His recearch interests include witness psychology, investigative psychology, legal psychology, sexual behaviour and evolutionary psychology. Antti Ritvanen MSc (psychology) is a school psychologist. The present article is partly based on his master's thesis in psychology.

Posterior calvarial vault osteodistraction (PCVO) has become increasingly popular in the correction of craniosynostosis. When compared to cranioplasty, PCVO offers a shorter, less invasive operation, greater intracranial volume advancement and a lower rate of relapse. In general, distraction protocols are based primarily on clinical observations rather than systematic research. Faster distraction protocols may reduce complications. However, distraction protocols producing higher forces can increase complications. Thus, we need to understand these forces in order to improve distraction protocols and devices. We developed a force measurement method that can be used on PCVO devices. Here, we present preliminary data about the forces developed during PCVO. We measured the forces in four bicoronal craniosynostosis patients during PCVO. We observed a linear-like trend between the force increase and the distraction distance within distraction sessions. We also observed a step-wise force increase between distraction sessions and found that the distraction force relaxed rapidly shortly after the distraction session. The mean maximum pre-distraction force for one distracter was 20.4 N, while the mean maximum end-distraction force for one distracter was 57.6 N. Our data suggests that current treatment protocols might be re-evaluated favouring shorter distraction distances and more frequent distraction sessions.

Mean [Formula: see text] preoperative ICV values were 895.0 [Formula: see text] 153.1 [Formula: see text] and 896.4 [Formula: see text] 147.2 [Formula: see text] as measured with MBM and MSM, respectively. Corresponding one-year postoperative values were 1,238.3 [Formula: see text] 118.7 [Formula: see text] and 1,250.1 [Formula: see text] 117.5 [Formula: see text]. The MBM allowed ICV determination from one-week postoperative datasets. Measurement time with MBM was 4 CONCLUSIONS: MBM is an efficient method for determining the ICV of craniosynostosis patients, allowing the measurement of skulls with bony defects. The repeatability and short measurement time of MBM are attributable to the user interference and assessment of the measurement process.

In their intended configuration, there is no clinically significant difference in fixation strength between ultrasound-activated pins and resorbable screws.