Integrating Electrophysiological, Mechanical, and Optical Methods to Define the Mechanisms of Painful Facet Joint Injury

Persistent pain is a common occurrence following whiplash injuries produced during motor vehicle crashes. The cervical facet joint and its capsule have often been identified as the source of chronic pain in patients with whiplash-associated disorders. However, for the majority of patients, no radiographic evidence of cervical spine injury is present. A capsular ligament stretch-based mechanism for initiating facet-mediated pain has been proposed based on human cadaveric studies of the facet joint kinematics during whiplash stimulations. However, without direct evidence of capsule damage during whiplash, the biomechanical and physiological mechanisms by which altered vertebral kinematics produce a facet capsule injury have not been fully elucidated. The goal of this thesis was to identify the facet joint loading conditions that produce microstructural damage to the facet capsular ligament and determine whether such loading can initiate neuronal plasticity in the spinal cord. Using a rat model of cervical facet joint loading, spinal neuron hyperexcitability was quantified from extracellular voltage recordings after imposing joint loading conditions that do and do not produce persistent pain symptoms. To determine whether neuronal hyperexcitability corresponds to a detectable change in the microstructure of the facet capsular ligament, a quantitative polarized light imaging technique was employed to define collagen fiber kinematics during capsule loading. A vector correlation analysis technique was developed to localize anomalies in the fiber kinematics of the human facet capsular ligament during tensile loading and was compared to changes in the mechanical response of the tissue during loading. The collagen fiber kinematics of the rat facet capsular ligament were also defined and compared to the joint loading conditions that produce neuronal plasticity and persistent pain symptoms. Altered fiber alignment and changes in the mechanical function of the human facet capsule were quantified after a subfailure vertebral retraction to determine the potential for microstructural damage in the facet capsule following whiplash-like motion. This work demonstrates that facet capsule stretch can cause microstructural changes to the capsular ligament in the absence of capsule rupture and establishes a framework to identify the mechanisms of facet joint injury and the development of central sensitization and persistent pain

Philosophy by the Pint

Senior Project submitted to The Division of Social Studies of Bard Colleg

The Reality of Measuring Human Service Programs: Results of a Survey

In the summer of 2013, Idealware created and distributed a survey to learn how human service organizations from their own mailing list are actually using technology to measure and evaluate the outcomes of their programs. The suvey looked at a general overview of outcomes measurement and program evaluation topics, from how frequently they look at data and how much time they spend doing so to what types of metrics the organizations were tracking. To further understand the realities of measuring program effectiveness, Idealware conducted a site visit and interview of three human service organizations in Portland, Maine. The results clearly show that the respondents are struggling to measure their programs

Contactless system and method for assessing tissue viability and other hemodynamic parameters

A contactless system for assessing tissue viability and other hemodynamic parameters includes one or more light sources configured to emit lights at a predetermined wavelength sensitive to hemoglobin concentration associated with spontaneous hemodynamic oscillations at tissue in a predetermined area of a human subject. One or more polarizers are each coupled to one or more of the one or more light sources and are configured to polarize the light to a polarized state such that the polarized light in the polarized state diffuses into the tissue in the predetermined area at a predetermined depth and the polarized light is maintained in the polarized state at the predetermined depth. One or more detectors each including a detector polarizer coupled thereto are configured to discriminate the light maintained in the polarized state and at the predetermined depth and are configured to generate a plurality of frames of the tissue in the predetermined area at the predetermined depth. A controller is coupled to the one or more light sources and the one or more detectors. The controller is configured to: acquire the plurality of frames, select a region of interest having the same coordinates for each of the plurality of frames, average the number of pixels within each region of interest to create a raw reference signal, detrend the raw reference signal to create a detrended raw reference signal, perform frequency domain analysis of the detrended raw reference signal, identify a frequency band of interest associated with the spontaneous hemodynamic oscillations, and perform an inverse fast Fourier transform within the frequency band of interest to generate a reference signal indicative of blood volume oscillations at a selected spontaneous hemodynamic oscillation. For each sample of the reference signal at a predetermined point in time, the controller multiplies the sample by each pixel of a frame at the same predetermined point in time to generate a three-dimensional coordinate matrix including a plurality of correlation matrix frames at each predetermined point in time. The controller adds the plurality of correlation matrix frames at each predetermined point in time to generate a two-dimensional hemodynamic map indicative of the strength of the spontaneous hemodynamic oscillation to assess the viability of the tissue in the predetermined area

Vector Correlation Technique for Pixel-wise Detection of Collagen Fiber Realignment During Injurious Tensile Loading

Excessive soft tissue loading can produce adverse structural and physiological changes in the absence of any visible tissue rupture. However, image-based analysis techniques to assess microstructural changes during loading without any visible rupture remain undeveloped. Quantitative polarized light imaging (QPLI) can generate spatial maps of collagen fiber alignment during loading with high temporal resolution and can provide a useful technique to measure microstructural responses. While collagen fibers normally realign in the direction that tissue is loaded, rapid, atypical fiber realignment during loading may be associated with the response of a local collagenous network to fiber failure. A vector correlation technique was developed to detect this atypical fiber realignment using QPLI and mechanical data collected from human facet capsular ligaments (n=16) loaded until visible rupture. Initial detection of anomalous realignment coincided with a measurable decrease in the tissue stiffness in every specimen and occurred at significantly lower strains than those at visible rupture (ρ \u3c 0.004), suggesting this technique may be sensitive to a loss of microstructural integrity. The spatial location of anomalous realignment was significantly associated with regions where visible rupture developed (ρ \u3c 0.001). This analysis technique provides a foundation to identify regional differences in soft tissue injury tolerances and relevant mechanical thresholds

Cervical facet capsular ligament yield defines the threshold for injury and persistent joint-mediated cervical pain

The cervical facet joint has been identified as a source of neck pain, and its capsular ligament is a likely candidate for injury during whiplash. Many studies have shown that the mechanical properties of ligaments can be altered by subfailure injury. However, the subfailure mechanical response of the facet capsular ligament has not been well defined, particularly in the context of physiology and pain. Therefore, the goal of this study was to quantify the structural mechanics of the cervical facet capsule and define the threshold for altered structural responses in this ligament during distraction. Tensile failure tests were preformed using isolated C6/C7 rat facet capsular ligaments (n=8); gross ligament failure, the occurrence of minor ruptures and ligament yield were measured. Gross failure occurred at 2.45±0.60 N and 0.92±0.17 mm. However, the yield point occurred at 1.68±0.56 N and 0.57±0.08 mm, which was significantly less than gross failure (p\u3c0.001 for both measurements). Maximum principal strain in the capsule at yield was 80±24%. Energy to yield was 14.3±3.4% of the total energy for a complete tear of the ligament. Ligament yield point occurred at a distraction magnitude in which pain symptoms begin to appear in vivo in the rat. These mechanical findings provide insight into the relationship between gross structural failure and painful loading for the facet capsular ligament, which has not been previously defined for such neck injuries. Findings also present a framework for more in-depth methods to define the threshold for persistent pain and could enable extrapolation to the human response

Contactless system and method for assessing tissue viability and other hemodynamic parameters

A contactless system for assessing tissue viability and other hemodynamic parameters includes one or more light sources configured to emit lights at a predetermined wavelength sensitive to hemoglobin concentration associated with spontaneous hemodynamic oscillations at tissue in a predetermined area of a human subject. One or more polarizers are each coupled to one or more of the one or more light sources and are configured to polarize the light to a polarized state such that the polarized light in the polarized state diffuses into the tissue in the predetermined area at a predetermined depth and the polarized light is maintained in the polarized state at the predetermined depth. One or more detectors each including a detector polarizer coupled thereto are configured to discriminate the light maintained in the polarized state and at the predetermined depth and are configured to generate a plurality of frames of the tissue in the predetermined area at the predetermined depth. A controller is coupled to the one or more light sources and the one or more detectors. The controller is configured to: acquire the plurality of frames, select a region of interest having the same coordinates for each of the plurality of frames, average the number of pixels within each region of interest to create a raw reference signal, detrend the raw reference signal to create a detrended raw reference signal, perform frequency domain analysis of the detrended raw reference signal, identify a frequency band of interest associated with the spontaneous hemodynamic oscillations, and perform an inverse fast Fourier transform within the frequency band of interest to generate a reference signal indicative of blood volume oscillations at a selected spontaneous hemodynamic oscillation. For each sample of the reference signal at a predetermined point in time, the controller multiplies the sample by each pixel of a frame at the same predetermined point in time to generate a three-dimensional coordinate matrix including a plurality of correlation matrix frames at each predetermined point in time. The controller adds the plurality of correlation matrix frames at each predetermined point in time to generate a two-dimensional hemodynamic map indicative of the strength of the spontaneous hemodynamic oscillation to assess the viability of the tissue in the predetermined area

Contactless system and method for assessing tissue viability and other hemodynamic parameters

A contactless system for assessing tissue viability and other hemodynamic parameters includes one or more light sources configured to emit lights at a predetermined wavelength sensitive to hemoglobin concentration associated with spontaneous hemodynamic oscillations at tissue in a predetermined area of a human subject. One or more polarizers are each coupled to one or more of the one or more light sources and are configured to polarize the light to a polarized state such that the polarized light in the polarized state diffuses into the tissue in the predetermined area at a predetermined depth and the polarized light is maintained in the polarized state at the predetermined depth. One or more detectors each including a detector polarizer coupled thereto are configured to discriminate the light maintained in the polarized state and at the predetermined depth and are configured to generate a plurality of frames of the tissue in the predetermined area at the predetermined depth. A controller is coupled to the one or more light sources and the one or more detectors. The controller is configured to: acquire the plurality of frames, select a region of interest having the same coordinates for each of the plurality of frames, average the number of pixels within each region of interest to create a raw reference signal, detrend the raw reference signal to create a detrended raw reference signal, perform frequency domain analysis of the detrended raw reference signal, identify a frequency band of interest associated with the spontaneous hemodynamic oscillations, and perform an inverse fast Fourier transform within the frequency band of interest to generate a reference signal indicative of blood volume oscillations at a selected spontaneous hemodynamic oscillation. For each sample of the reference signal at a predetermined point in time, the controller multiplies the sample by each pixel of a frame at the same predetermined point in time to generate a three-dimensional coordinate matrix including a plurality of correlation matrix frames at each predetermined point in time. The controller adds the plurality of correlation matrix frames at each predetermined point in time to generate a two-dimensional hemodynamic map indicative of the strength of the spontaneous hemodynamic oscillation to assess the viability of the tissue in the predetermined area

Comparing Outcomes of Robotic-Assisted versus Conventional Laparoscopic Hiatal Hernia Repair

Introduction. Robotic-assisted laparoscopic surgery for anti-reflux and hiatal hernia surgery is becoming increasingly prevalent. The purpose of this study was to compare hospital length of stay and outcomes of robotic-assisted versus conventional laparoscopic hiatal hernia repair. Methods. A retrospective review was conducted of 58 patients who underwent robotic-assisted laparoscopic (n = 42, 72.4%) or conventional laparoscopic (n = 16, 27.6%) hiatal hernia repair. Results. Patient characteristics and comorbidities were similar between groups. The robotic-assisted group had a significantly higher use of fundoplication (81.3% vs. 38.1%; p = 0.007). Complications observed between the robotic-assisted and conventional laparoscopic groups were pneumothorax (6.3% vs. 11.9%, p = 1.000), infection (0% vs. 4.8%, p = 1.000), perforation (0% vs. 2.4%, P=1.000), bleeding (6.3% vs. 2.4%, p = 0.479), ICU admission (31.3% vs. 11.9%, p = 0.119), and mechanical ventilation (18.8% vs. 2.4%, p = 0.60). There were no reported complications of dysphagia, DVT/PE, MI, or death in either group. Hospital length of stay was similar for robotic vs conventional patients (3.0 vs. 2.5 days, p = 0.301). Conclusions. This study’s data showed robotic-assisted hiatal hernia repair has comparable outcomes to conventional laparoscopic repair

Electrostatic Beneficiation of Lunar Regolith: Applications in In-Situ Resource Utilization

Upon returning to the moon, or further a field such as Mars, presents enormous challenges in sustaining life for extended periods of time far beyond the few days the astronauts experienced on the moon during the Apollo missions. A stay on Mars is envisioned to last several months, and it would be cost prohibitive to take all the requirements for such a stay from earth. Therefore, future exploration missions will be required to be self-sufficient and utilize the resources available at the mission site to sustain human occupation. Such an exercise is currently the focus of intense research at NASA under the In-situ Resource Utilization (ISRU) program. As well as oxygen and water necessary for human life, resources for providing building materials for habitats, radiation protection, and landing/launch pads are required. All these materials can be provided by the regolith present on the surface as it contains sufficient minerals and metals oxides to meet the requirements. However, before processing, it would be cost effective if the regolith could be enriched in the mineral(s) of interest. This can be achieved by electrostatic beneficiation in which tribocharged mineral particles are separated out and the feedstock enriched or depleted as required. The results of electrostatic beneficiation of lunar simulants and actual Apollo regolith, in lunar high vacuum are reported in which various degrees of efficient particle separation and mineral enrichment up to a few hundred percent were achieved