The intralaminar screw construct has been recently introduced in C6-C7 fixation. The aim of the study is to compare the stability afforded by three different C7 posterior fixation techniques using a three-dimensional finite element model of a C6-C7 cervical spine motion segment. Finite element models representing three different cervical anchor types (C7 intralaminar screw, C7 lateral mass scre...

The earliest growth of post-metamorphic (postlarval) shells in two species of Eohadrotreta is described from the Cambrian Shuijingtuo Formation of South China. Two different growth patterns can be observed by quantifying developmental variations in size and shape of successive stages of post-metamorphic shell growth (including the pedicle foramen forming stage, pedicle foramen enclosing stage a...

INTRODUCTION: In a pedicle screw fixation, the degree of osseointegration between a screw and the bone is an essential factor for the stability and fusion. In patients with osteoporosis, however, there is a high possibility for a pedicle screw loosening. Owing to this, there is a difficulty in determining the surgical indications. Previous biomechanical studies have reported that a pedicle scre...

Introduction: Despite widespread use of pedicles in lumbar spine fixation, relatively little is known regarding variations in pedicle structure particularly in osteoporosis. It is valuable to understand this relationship because pedicles provide an important area for screw fixation and a point of complication when screws penetrate through weak pedicle walls into adjacent structures. Hirano et a...

A cortical bone graft on a muscle pedicle was taken from the ulna and transferred to bridge a complete defect of the radius in 16 dogs. In 14 control dogs a free graft was used, that is, one without a muscle pedicle. Union in the group with pedicle grafts was far superior to that in the group with free grafts, mainly because in those with pedicle grafts there was good subperiosteal new bone for...

The use of pedicle screw instrumentation in the spine has evolved over the last two decades. The initial use of pedicle screws began in the lumbar spine. As surgeons have become more comfortable with the complex anatomy required for accurate screw placement, the use of pedicle instrumentation has evolved to include their use in the thoracolumbar and thoracic spine. The impetus behind their incr...

P edicle screw fixation for spinal stabilization is now commonplace in spine surgery. Traditionally, pedicle screws are placed through a trajectory in which screw insertion utilizes a transpedicular path through the axis of the pedicle, either paralleling the end plate, as in the straightforward trajectory, or following the anatomic axis of the pedicle with an approximately 22° cephalocaudal tr...

Background Propeller flaps require torsion of the vascular pedicle of up to 180 degrees. Contrary to free flaps, where the relevance of an intact vascular pedicle has been documented, little is known regarding twisted pedicles of propeller flaps. As secondary surgeries requiring undermining of the flap are common in the extremities, knowledge regarding the necessity to protect the pedicle is re...

Malpositioning of cervical screws risks neurovascular injury. A cervical screw fixation system can provide proper rigidity, alignment correction, and high rates of fusion afforded by high pullout biomechanical strength. The objective is to assess the dimensions and axis of the C3-C7 cervical pedicles. A 1-mm slice thickness computed tomography (CT) scan of the cervical spine of 30 patients (15 ...

We reported a technical report of traumatic lower cervical spondylolisthesisca used by bilateral pedicle fracture, without neurological compression. The patient was treated with the minimally invasive technique of percutaneous pedicle screw fixation. Fracture healing and normal cervical motion were confirmed by plain films and physical examinations on the 18-monthpostoperatively. The technique ...