Diffuse reflectance spectroscopy for breach detection during pedicle screw placement: a first in vivo investigation in a porcine model

BACKGROUND: The safe and accurate placement of pedicle screws remains a critical step in open and minimally invasive spine surgery, emphasizing the need for intraoperative guidance techniques. Diffuse reflectance spectroscopy (DRS) is an optical sensing technology that may provide intraoperative guidance in pedicle screw placement. PURPOSE:...

Diffuse reflectance spectroscopy, a potential optical sensing technology for the detection of cortical breaches during spinal screw placement

Safe and accurate placement of screws remains a critical issue in open and minimally invasive spine surgery. We propose to use diffuse reflectance (DR) spectroscopy as a sensing technology at the tip of a surgical instrument to ensure a safe path of the instrument through the cancellous bone of the vertebrae. This approach could potentially...

Diffuse reflectance spectroscopy accurately identifies the pre-cortical zone to avoid impending pedicle screw breach in spinal fixation surgery

Pedicle screw placement accuracy during spinal fixation surgery varies greatly and severe misplacement has been reported in 1-6.5 % of screws. Diffuse reflectance (DR) spectroscopy has previously been shown to reliably discriminate between tissues in the human body. We postulate that it could be used to discriminate between cancellous and...

What is an Appropriate Temporal Sampling Rate to Record Floating Car Data with a GPS?

Floating car data (FCD) recorded with the Global Positioning System (GPS) are an important data source for traffic research. However, FCD are subject to error, which can relate either to the accuracy of the recordings (measurement error) or to the temporal rate at which the data are sampled (interpolation error). Both errors affect movement...

Why GPS makes distances bigger than they are

Global navigation satellite systems such as the Global Positioning System (GPS) is one of the most important sensors for movement analysis. GPS is widely used to record the trajectories of vehicles, animals and human beings. However, all GPS movement data are affected by both measurement and interpolation errors. In this article we show that...

Design as a synthesis of spaces: Using the P-S framework

Designing is a multi-dimensional phenomenon and is difficult to describe through one disciplinary research lens only. This paper uses a framework within which multiple theories of designing could be informed of their role and explanatory power. The Product space and Social Space framework describes the scope of designing activities and it allows...

Designing: Insights from weaving theories of cognition and design theories

This paper addresses the issue of ‘What is designing?’ from an unconventional perspective and aims to advance our understanding of what design really is. Designing has been studied from different perspectives but the underlying theoretical basis of studying the act has often been dispersed and not clear. To address these shortcomings, the paper...

Specifying the calibration of static pressure systems for the safe use of 1000ft vertical separation standard in North Atlantic jet traffic

A theory of safe separation standards for air traffic control

Expressions for collision risk are given in terms of elementary probabilities and of frequencies with which aircraft pass each other in the three dimensions of space. Techniques are proposed for setting confidence limits to estimates of the probabilities, including those that depend on the occurrence of large, rare flying errors, so that similar...

Separation standards in the North Atlantic Region, 1965-71, in the light of recent measurements of flying errors

Interpretations are proposed for the sets of measurements which have been made of track-keeping and height-keeping errors. From these measurements, estimates are made of the elementary probabilities and frequencies which make up the expressions for collision risk derived in earlier papers of this series. Assessments are then made of the levels...

An analysis of planned aircraft proximity and its relation to collision risk, with special reference to the North Atlantic region 1965-71

Expressions are derived for the number of collisions to be expected within a traffic area in a period of time. These are given in terms of the frequency of large flying errors and the total time during which aircraft fly nominally at or near a statutory minimum of separation from each other (called "proximity"). Theoretical techniques are...

An analysis of jet traffic crossing the North Atlantic on the 7th and 8th September 1962

Information recorded on flight progress strips and teleprinter messages has been used to study jet traffic controlled by the Gander, Prestwick, Reykjavik, Shannon and Sondrestrom Oceanic Area Control Centres during a busy period in 1962. An analysis is given of the distribution of the traffic in space and time, the extent of restrictions imposed...