Brain retraction injury.

This paper reviews the literature of the brain retraction injury during the last century. The review focused on the instrument characteristic as well as the physiopathological and histopathological damage of the brain induced by brain retraction. It was found that lesions were induced by cerebral ischemia. We conclude that a better monitoring system needs to be developed to avoid brain injury.

Advances in ICP monitoring techniques.

With the advent of newer devices for measuring intracranial pressure (ICP) and cerebral metabolism, more alternatives continue to rise aiming to control ICP. This manuscript presents a proposed analysis of different ICP monitoring devices in order to make appropriate selection of them in our clinical setting including general and pediatric applications. A systematic review of the literature was made analyzing the technical advances in ICP monitoring. The recent in vitro and in vivo tests as well as mathematical/computer models were reviewed. Practical applications of principles were discussed and compared based on the mode of pressure transformation. A ventricular catheter connected to an external strain gauge transducer or catheter tip pressure transducer device is considered to be the most accurate method of monitoring ICP and enables therapeutic CSF drainage. The significant infections or hemorrhage associated with ICP devices causing patients morbidity are clinically rare and should not deter the decision to monitor ICP. Parenchymal catheter tip pressure transducer devices are advantageous when ventricular ICP cannot be obtained or if there is an obstruction in the fluid couple, though they have the potential for significant measurement differences and drift due to the inability to recalibrate. Subarachnoid or subdural fluid-coupled devices and epidural ICP devices are currently less accurate. With an increasing miniaturization of the transducers, fiberoptic systems have been developed, however, there is a problem of measurement accuracy during the period of patient monitoring and external calibration should be performed frequently to ensure constant accuracy. Ventriculostomies continue to have a pivotal role in ICP control. With a rational understanding of the applications and limitations of the different ICP monitoring devices, the outcome for critically ill neurological patients is optimized.

Biomechanical properties of high-density polyethylene for pterional prosthesis.

The pterional approach is the most popular surgical technique in aneurysm and skull base tumor removal. Reconstruction of the temporal contour deformity due to craniotomy requires graft implantation. Porous high-density polyethylene (PHDPE) as a craniofacial and pterional implant material recently became available. However, material properties of the pterional implant are not yet known. In order to measure the biomechanical properties of PHDPE, we implemented the tensile test, the three-point bending test and the water displacement method for density measurement. Elastic modulus varies from 227 to 307MPa. Density range is 0.68 and 0.7 depending on the size of pores. The data can be used to study the character of the porous high-density polyethylene implant, how it resists stress or fatigue in combination with conventional plating systems.

Burr hole cover for ventriculoperitoneal shunts and ventriculostomy: technical note.

In patients who have undergone intracranial procedures, bone gaps or burr holes often result in small but undesirable scalp or skin depressions. The authors designed a burr hole cover for hydrocephalus shunt system or external ventricular drainage, which is shaped to alleviate the deformity of the burr hole by filling the bone defect and allowing the passage of the ventricular catheter. The specifications of this device and its clinical application are described.

Three layer impact simulation for large cranioplasty using non-linear finite element model.

In this study, we conducted biomechanical study about implant material and behavior of large cranioplasty upon post-operative impact injury. Previous studies utilized a surface model of the skull and large cranium patch (defect area is 46.7 cm2)[1,2,3,4]. It had single layer with thickness of adult skull as 7 cm in the parietal bone. After construction of the finite element model, the mesh and node data were analyzed for the static behavior of the patch. Four-node and three-node quadrilateral shell elements were mainly used in this model to adapt easily to complex shapes. The overall model consists of 4,740 nodes, 2,168 solid elements, and 4,736 shell elements. Even though, the elements could demonstrate the displacement, stress, and strain by longitudinal along the force direction, subsequent result could not reveal the dynamic behavior of the model. Normal adult skull is consisting of three layers (inner, outer and diploë layer). This structure resembles composite materials that behave differently upon impact. In order to overcome limitation of previous model, we designed physiological model and analyzed dynamic behavior with new implant materials. The composite implant with two popular materials and middle polymer layer was evaluated and compared with bony material.

CNS child abuse: epidemiology and prevention.

The problem of child abuse and the central nervous system implications are reviewed from a multidimensional approach. Statistics regarding prevalence, risk factors, epidemiological considerations, and physiological aspects are studied. The incidence is reviewed in the United States and in other countries where incidence and social services are also described. Implications for prevention efforts are considered.