No abstract

Background: To better understand the underlying mechanisms involved in trunk motion during a tennis serve, this study aimed to examine the (1) relative motion of the middle and lower trunk and (2) lower trunk muscle activity during three different types of tennis serves -flat, topspin, and slice.

After classic Hirabayashi open-door laminoplasty, opened laminae showed reclosure at 6 months, with approximately 10% decrease in AP diameter and opening angle. Postoperative lamina closure was associated with recurrent spinal cord compression, suggesting the need for other augmenting techniques that keep the laminae opened.

The Dynesys dynamic instrumentation system seems to stabilize degenerative spondylolisthesis. As expected in the degenerative lumbar spine, the segmental motion of the implanted level in this study was limited and considerably less than normal spinal motion.