Light intensity distribution in images from rigid endoscopes used in minimal access sinus surgery.

Objectives/hypothesis: To investigate the pattern of intensity levels in images generated by the two most commonly used rigid endoscopes angulations in sinus surgery: 0° and 30°.

Methods: An enclosed light box containing an optical square grid, under endoscope illumination set just below saturation level, was used for measuring light distribution levels across test images. Endoscopes with 0° and 30° angulations were tested at 10 mm from the grid, typical for sinus surgery.

Finite element analysis of a condylar support prosthesis to replace the temporomandibular joint.

This paper presents a finite element study of a temporomandibular joint (TMJ) prosthesis in which the mandibular component sits on the condyle after removal of only the diseased articular surface and minimal amount of condylar bone. The condylar support prosthesis (CSP) is customised to fit the patient and allows a large part of the joint force to be transmitted through the condyle to the ramus, rather than relying only on transfer of the load by the screws that fix the prosthesis to the ramus. The 3-dimensional structural finite element analysis compared a design of CSP with a standard commercial prosthesis and one that was modified to fit the ramus, to relate the findings to the different designs and geometrical features.

Computer-assessed performance of psychomotor skills in endoscopic otolaryngology surgery: construct validity of the Dundee Endoscopic Psychomotor Otolaryngology Surgery Trainer (DEPOST).

Background: This study was undertaken to introduce and establish the value of the Dundee Endoscopic Psychomotor Otolaryngology Surgery Trainer (DEPOST) as a customisable, objective real-time scoring system for trainee assessment. The construct validity of the system was assessed by comparing the performance of experienced otolaryngologists with that of otolaryngology trainees, junior doctors and medical students.

Methods: Forty two subjects (13 Consultants, 8 senior trainees, 13 junior trainees and 8 junior doctors/medical students) completed a single test on DEPOST.

Automatic glare removal in endoscopic imaging.

Background: Glare from surgical instruments and tissue surfaces often occurs during endoscopic procedures and can be disturbing to the operator. The brightness level of the light source can be reduced, but at the expense of overall image clarity, so alternative solutions are needed for removing glare. Digital image-processing methods offer the opportunity to lessen or eliminate glare by reducing the intensity of the affected parts of the image.

Electromechanical behaviour of Nafion-based soft actuators.

Soft actuators based on Ionic Polymer-Metal Composites (IPMCs) are of considerable interest for applications in biomedical devices and robotics. In this work, thin commercial and thick laboratory-prepared Nafion membranes were made into model IPMC actuator devices by incorporation of Pt electrode layers. In extensive electromechanical tests the maximum average tip displacement and maximum force generated were recorded.

Measurement of osteotomy force during endoscopic sinus surgery.

Greater understanding of the surgeon's task and skills are required to improve surgical technique and the effectiveness of training. Currently, neither the objective measurement of osteotomy forces during endoscopic sinus surgery (ESS) nor the validity of the properties of cadaver materials, are well documented. Measurement was performed of peak axial osteotomy force during ESS.

Do high-speed drills generate high-frequency noise in mastoid surgery?

Background: The introduction of increasingly high speed drills for mastoid surgery has heightened the concern that cochlea damage may occur in both the operated and nonoperated ear. It has been observed clinically that this damage could be associated with frequencies above 8,000 Hz and that, to observe these changes, high-frequency audiometry should be performed. Previous studies have investigated noise transmission to the cochlea at frequencies below 4,000 Hz only.

Enhanced cell colonization of collagen scaffold by ultraviolet/ozone surface processing.

Both physical and chemical crosslinking methods have been shown to be effective in improving the biological stability and mechanical properties of porous collagen scaffolds. However, the wetting of the collagen fibril surface by a culture medium is reduced and it is difficult for the medium to diffuse into the 3D structure of a porous collagen scaffold. This article reports a strategy for the surface processing of crosslinked collagen scaffolds by an integrated ultraviolet/ozone perfuse processing technique.

Influence of interaction energy between Si-doped diamond-like carbon films and bacteria on bacterial adhesion under flow conditions.

Diamond-like carbon (DLC) films, especially modified DLC films with doped elements as biomaterials for medical devices have been attracting great interest. In this article, the bacterial adhesion behavior on DLC films, Si-doped DLC films, and stainless steel 316L was investigated with Pseudomonas aeruginosa ATCC 33347, which frequently causes medical device-associated infections. This was done under laminar flow conditions in a flow chamber at 37 degrees C.

Contact angles of diiodomethane on silicon-doped diamond-like carbon coatings in electrolyte solutions.

The influence of surrounding electrolyte type and concentration on the contact angle of hydrophobic diiodomethane on silicon-doped diamond-like carbon (DLC) coatings was examined to provide insight into how the presence of electrolytes in the solution influences adhesion of hydrophobic material to doped DLC surfaces. There was a small but statistically significant increase of contact angle with increasing electrolyte concentration over the range from 0 to approximately 0.01 M, after which the contact angle was virtually unaffected by further increase in the concentration of electrolyte.

Adhesion of protein residues to substituted (111) diamond surfaces: an insight from density functional theory and classical molecular dynamics simulations.

Protein-repellent diamond coatings have great potential value for surface coatings on implants and surgical instruments. The design of these coatings relies on a fundamental understanding of the intermolecular interactions involved in the adhesion of proteins to surfaces. To get insight into these interactions, adhesion energies of glycine to pure and Si and N-doped (111) diamond surfaces represented as clusters were calculated in the gas phase, using density functional theory (DFT) at the B3LYP/6-31G* level.

Singularity characteristics of needle EMG IP signals.

Clinical electromyography (EMG) interference pattern (IP) signals can reveal more diagnostic information than their constituents, the motor unit action potentials (MUAPs). Singularities and irregular structures typically characterize the mathematically defined content of information in signals. In this paper, a wavelet transform method is used to detect and quantify the singularity characteristics of EMG IP signals using the Lipschitz exponent (LE) and measures derived from it.

Interscale wavelet maximum-a fine to coarse algorithm for wavelet analysis of the EMG interference pattern.

A method has been developed, interscale wavelet maximum (ISWM), for characterising the electromyogram (EMG) interference pattern to assist in the diagnosis of neuromuscular disease. EMG signals are decomposed with the redundant dyadic wavelet transform and wavelet maxima (WM) are found. Thresholding methods are applied to remove WM due to noise and background activity.