Computer Modeling of Anatomical Structure: A Representative Example of Modeling the Inguinal Canal

As computers become an increasingly important part of medical education, a proper understanding of the techniques and applications of computer aided modeling is vital. An initial overview of medical imaging and the techniques of computer modeling is presented. Construction of three-dimensional models of anatomical structures is then discussed in great detail with specific focus on modeling structures like the inguinal canal. The inguinal canal is one region where computer modeling efforts should be directed because it presents a special challenge. Understanding the walls, borders and layering of the inguinal canal is especially difficult but vital to accurate clinical diagnoses of hernias. Computer-based instruction based on high-quality three dimensional images promises to greatly enhance students’ learning and comprehension of difficult anatomical structures and relationships

Physical Therapy Interventions and Outcomes in a Patient with Transfemoral Amputation Following Sound Side Total Knee Arthroplasty: A Case Report

Background: Following transfemoral amputation (TFA), contralateral limb overuse leads to osteoarthritis (OA). Explanations include gait abnormalities, increased knee load, and hopping activities without prosthesis. Unilateral TFA patients may require total knee arthroplasty (TKA) to improve function. Purpose: Determine benefits of standard physical therapy (PT) and augmented by high intensity, whole-body strengthening program. Case Description and Methods: Patient with TFA, limited community ambulator and left knee OA, underwent TKA to restore function. PT examinations, interventions, and outcomes at 1-week pre-TKA to 1-year post-TKA; outcomes measures were Single Leg Stance Test (SLST), Four Square Step Test (FSST), Timed Up and Go Test (TUG), and Six Minute Walk Test (6MWT). Finding: Patient achieved functional independence, gait, lower extremity strength and active range of motion (AROM) goals. Outcomes and Conclusion: Outcomes in TUG and FSST equaled age and sex matched non-amputees. Standard TKA PT protocols contributed to patient success, while high intensity, whole-body strengthening program contributed to patient achievements

Improvements in Physical Functional Performance Test 10 (PFP-10) in an Amputee Following Contralateral Total Knee Arthroplasty

Introduction: Due to abnormal gait patterns in patients with lower extremity amputation (LEA), it has been hypothesized that this population experiences early onset of osteoarthritis (OA) of sound side limb causing pain and impaired function which may lead to surgical intervention. Purpose: The purpose of this case report is to present a transfemoral LEA who received sound limb total knee arthroplasty (TKA). Just prior to and immediately following surgery, there is a time period where a person with LEA can experience a decrease in physical functional performance and become dependent on assistance for daily activities. Case Description: The patient was a 56-year-old male who contracted necrotizing fasciitis in the right knee that resulted in a transfemoral LEA three years later. The onset of OA of the sound side knee was due to abnormal gait patterns and increased stresses. A TKA was performed to improve function and decrease pain. The Continuous Scale-Physical Functional Performance-10 (CS-PFP-10) test consists of 10 standardized daily living tasks that evaluate overall physical functional performance and performance in five individual functional domains: upper body strength (UBS), upper body flexibility (UBF), lower body strength (LBS), balance and coordination (BAL), and endurance (END). Physical Functional Performance (PFP) Total and individual domain scores of 0-47 indicates: Increased likelihood of functional dependence. Scores of 48-56 indicates: Likely at risk of losing independence, while scores of 57-100 indicate: Independent function likely. Outcomes: CS-PFP-10 test was administered one week preoperative as well as one, three, six and twelve-month post-operative TKA. The patient received skilled physical therapy and progressed to a supervised wellness program focusing on strength, balance, coordination and endurance. The skilled physical therapy lasted six months and supervised wellness up to one-year post surgery. One week preoperatively, three of five domains were at Increased likelihood of functional dependence, while two domains and PFP total were scored at the low end of at risk of losing independence. Following the one year of skilled physical therapy and supervised wellness program, all five domain scores as well as the total score were at the 70-95 range. Discussion: Due to the abnormal stresses placed on the sound limb during gait activities, a patient with a transfemoral amputation may develop early onset sound side OA. There is a dearth of evidence on unilateral LEA confounded by sound side TKA. There is a need for research in this population due to an increase in unilateral LEA and the need to develop a standard of care for optimal outcomes. A motivated patient with a LEA and sound side TKA can benefit from skilled physical therapy in terms of potentially attaining maximal functional independence with ADLs. Physical therapy should focus on rehabilitation for the TKA, but also must incorporate core strengthening, balance, coordination and endurance in order to improve physical functional performance to maintain independence. Introduction In the United States (U.S.), there are approximately 185,000 lower extremity amputations (LEA) per year, and in 2009 associated healthcare costs were over $8.3 billion.1,2 Amputations occur in patients with diabetes, vascular disease, trauma, cancer, congenital disorders, and infections.3 Angoules et al.4 reviewed 10 studies encompassing 451 patients, they examined the incidence of amputation following necrotizing fasciitis. The authors found that 22.3% of patients underwent limb amputation after failed attempts to control infection and avoid limb loss.4 Patients with LEA experience secondary impairments of osteoarthritis (OA) of the sound side limb.5,6 In unilateral LEA,7 it is important to recognize early onset OA and how function could improve with surgical intervention. OA is a chronic and degenerative synovial joint condition, primarily affecting articular cartilage. Late stage OA presents with persistent pain, which can be immobilizing.8 Abnormal gait patterns and joint mechanics, and lack of prosthetic confidence increases risk for knee OA in LEA patients.5,6 Dynamic analysis of transfemoral amputation (TFA) gait demonstrated decreased gait speed, cadence, and stride length, and increased stance phase on sound limb.9 New prosthetic technology has been developed to address unequal weight bearing through extremities in LEA to help prevent contralateral knee OA.10 However, not all patients have access to this technology. Similarly, rehabilitation access may also be disparate leading to highly individualized courses of prosthetic care, rehabilitation and outcomes. This case presents increased scores in Continuous Scale Physical Functional Performance Test (CS-PFP 10 Test) in a TFA patient with contralateral TKA following standard physical therapy (PT) interventions supplemented by high intensity, whole body strength training

Assessing Ground Reaction Forces and Degenerative Changes of Sound Limb in Unilateral Lower Extremity Amputees: A Systematic Review

Abstract Background: There is a rising number of individuals undergoing lower extremity amputation (LEA) and is associated with increased risk of comorbidities. Osteoarthritis (OA) and Degenerative Joint Disease (DJD) are conditions that cause reduction in an individual’s function, independence, and quality of life. Research Design: A search of multiple databases using terms associated with possible functional declines as evidenced by the International Classification of Functioning, Disability and Health (ICF), followed by assessment of evidence using the PEDro scoring method will be conducted. Multiple reviewers will screen, sort, rate and extract data from articles. Methods: A computer-aided literature search of PubMed, CINAHL, and Google Scholar was performed to identify studies published beginning in 2009 that investigated factors that contribute to degenerative changes in the contralateral limb of a unilateral LEA. Results: A total of 21 studies were selected from a total of 56 collected studies. Predictors of osteoarthritis (OA) following lower limb amputation include age, etiology, level of amputation, gender, Body Mass Index (BMI), comorbidity, pain, phantom pain, streng and OA. The impact of ground reaction forces on the sound limb varies between studies. In general, poor gait mechanics and resulting compensatory mechanisms are significant contributors to the occurrence of OA. Conclusion: There is a dearth of information relating to the prevention of degenerative changes in those with LEA and protocols for pain management and training pre- and post-joint replacement. The incidence of OA in the contralateral limb is still not fully understood. Further investigation into the biomechanics of compensatory mechanisms is necessary to fully understand the functional impact on the population. It is imperative to develop thorough physical therapy protocols for individuals in early onset of OA and those undergoing joint replacement due to degeneration

Predicting Walking Ability and Prosthetic Candidacy Following Lower Extremity Amputation; An Updated Systematic Review and Treatment Pathway

Background: There is not a clear compilation of existing literature that determines walking ability and prosthetic candidacy following lower extremity amputation (LEA). There is no multi-disciplinary instrument or patient centric decision-making protocol accepted that can predict walking ability and prosthetic candidacy nor support a treatment pathway. It is important to determine these factors to better assist clinicians in determining a patient’s MFCL K-level to assist with the delivery of proper prosthetic componentry. Medicare Functional Classification Level (MFCL) K-level is a 0 to 4-point scale of functional level for those with limb loss. The purpose of this systematic literature review is to further develop evidence-based LEA patient centric treatment pathways that determine prosthetic candidacy decisions for LEAs. This evidence will assist the healthcare team in the decision-making process. In a similar systematic review (SR), Kahle., et al. reported into 2016 on the prediction of walking ability following lower limb amputation (LLA). Methods: This search strategy was designed and similarly implemented from the previous Kahle SR based on predicting walking ability. An electronic literature search was executed from 8/1/2007 to 12/31/2015 using MEDLINE, EMBASE, CINAHL, and Cochrane. Results: After electronic search and a thorough review and elimination of articles, a total of 104 quality studies were identified. Of these, 78 were systematically reviewed in two previous reviews and eliminated. Twenty-six remained for full evaluation. These updated study conclusions are drawn from a total sample (n) of 46,651 subjects. The size of this updated study has increased the original Kahle., et al. report by including 300% more subjects for a combined total of 61,858 subjects in the two SRs. Conclusion: In the two combined SRs, cause of amputation (etiology), physical fitness, pre-amputation living status, amputation level, age, cognitive/mood disturbances, social support and comorbidities are included as moderate to strongly supported predictive factors of walking ability and prosthetic candidacy. These factors should be strongly considered in a detailed history and physical examination by the rehabilitation team and documented in the patient healthcare record

Serendipitous Geodesy from Bennu's Short-Lived Moonlets

The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx; or OREx) spacecraft arrived at its target, near-Earth asteroid (101955) Bennu, on December 3, 2018. The OSIRIS-REx spacecraft has since collected a wealth of scientific information in order to select a suitable site for sampling. Shortly after insertion into orbit on December 31, 2018, particles were identified in starfield images taken by the navigation camera (NavCam 1). Several groups within the OSlRlS-REx team analyzed the particle data in an effort to better understand this newfound activity of Bennu and to investigate the potential sensitivity of the particles to Bennu's geophysical parameters. A number of particles were identified through automatic and manual methods in multiple images, which could be turned into short sequences of optical tracking observations. Here, we discuss the precision orbit determination (OD) effort focused on these particles at NASA GSFC, which involved members of the Independent Navigation Team (INT) in particular. The particle data are combined with other OSIRIS-REx tracking data (radiometric from OSN and optical landmark data) using the NASA GSFC GEODYN orbit determination and geodetic parameter estimation software. We present the results of our study, particularly those pertaining to the gravity field of Bennu. We describe the force modeling improvements made to GEODYN specifically for this work, e.g., with a raytracing-based modeling of solar radiation pressure. The short-lived, low-flying moonlets enable us to determine a gravity field model up to a relatively high degree and order: at least degree 6 without constraints, and up to degree 10 when applying Kaula-like regularization. We can backward- and forward-integrate the trajectory of these particles to the ejection and landing sites on Bennu. We assess the recovered field by its impact on the OSIRIS-REx trajectory reconstruction and prediction quality in the various mission phases (e.g., Orbital A, Detailed Survey, and Orbital B)

Early Navigation Performance of the OSIRIS-REx Approach to Bennu

The New Frontiers-class OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) mission is the first American endeavor to return a sample from an asteroid. In preparation for retrieving the sample, OSIRIS-REx is conducting a campaign of challenging proximity-operations maneuvers and scientific observations, bringing the spacecraft closer and closer to the surface of near-Earth asteroid (101955) Bennu. Ultimately, the spacecraft will enter a 900-meter-radius orbit about Bennu and conduct a series of reconnaissance flybys of candidate sample sites before being guided into contact with the surface for the Touch and Go sample collection event. Between August and December 2018, the OSIRIS-REx team acquired the first optical observations of Bennu and used them for navigation. We conducted a series of maneuvers with the main engine, Trajectory Correction Maneuver, and Attitude Control System thruster sets to slow the OSIRIS-REx approach to Bennu and achieve rendezvous on December 3, 2018. This paper describes the trajectory design, navigation conops, and key navigation results from the Approach phase of the OSIRIS-REx mission

Preserving and Using Germplasm and Dissociated Embryonic Cells for Conserving Caribbean and Pacific Coral

Coral reefs are experiencing unprecedented degradation due to human activities, and protecting specific reef habitats may not stop this decline, because the most serious threats are global (i.e., climate change), not local. However, ex situ preservation practices can provide safeguards for coral reef conservation. Specifically, modern advances in cryobiology and genome banking could secure existing species and genetic diversity until genotypes can be introduced into rehabilitated habitats. We assessed the feasibility of recovering viable sperm and embryonic cells post-thaw from two coral species, Acropora palmata and Fungia scutaria that have diffferent evolutionary histories, ecological niches and reproductive strategies. In vitro fertilization (IVF) of conspecific eggs using fresh (control) spermatozoa revealed high levels of fertilization (>90% in A. palmata; >84% in F. scutaria; P>0.05) that were unaffected by tested sperm concentrations. A solution of 10% dimethyl sulfoxide (DMSO) at cooling rates of 20 to 30°C/min most successfully cryopreserved both A. palmata and F. scutaria spermatozoa and allowed producing developing larvae in vitro. IVF success under these conditions was 65% in A. palmata and 53% in F. scutaria on particular nights; however, on subsequent nights, the same process resulted in little or no IVF success. Thus, the window for optimal freezing of high quality spermatozoa was short (∼5 h for one night each spawning cycle). Additionally, cryopreserved F. scutaria embryonic cells had∼50% post-thaw viability as measured by intact membranes. Thus, despite some differences between species, coral spermatozoa and embryonic cells are viable after low temperature (−196°C) storage, preservation and thawing. Based on these results, we have begun systematically banking coral spermatozoa and embryonic cells on a large-scale as a support approach for preserving existing bio- and genetic diversity found in reef systems

Comparative Outcomes Assessment of the C-Leg and X2 Knee Prosthesis

Background There are more than 300,000 persons in the U.S. living with transfemoral amputation (TFA). Persons with TFA use a knee prosthesis for gait and mobility. Presently, the C-Leg microprocessor knee prosthesis is the standard of care. C-Leg has significantly improved safety and cost efficacy and has created modest gains in gait efficiency. Recently, a new prosthesis has introduced a new sensor array and processor that reportedly improves knee motion, stair function and standing stability. Early claims of the reported functional benefits of the new Genium knee (formerly X2) have not been validated in a rigorous clinical trial. Therefore, the purpose of this project was to determine if the Genium knee improves safety, function and quality of life compared to the current standard of care (C-Leg). Methods The study is a randomized AB crossover with a control group. Subjects must have used (and still be using) a C-Leg for a minimum of 1yr prior to enrollment. Inclusion criteria beyond this are unilateral transfemoral or knee disarticulation amputation for any etiology, community level ambulation (Medicare level 3 or above), independent ambulation and ability to independently provide written, informed consent. Once enrolled subjects utilize their same socket but receive a study foot (Trias or Axtion). Subjects are randomly assigned to either stay with their C-Leg or be fit with a Genium knee. Subjects accommodate and test (A phase) then crossover to the other knee condition and repeat the testing (B phase). A follow up phase of the study beyond the B phase is ongoing to study longer term preference. For AB assessment, three domains were assessed: Safety, function and quality of life. For safety, the PEQ-A survey of stumbles and falls, posturography (Biodex SD limits of stability and postural stability tests), 4 square step test and 2 minute ramp stand test were completed. For function, a series of timed walking tests, the amputee mobility predictor, kinematic gait assessment and physical functional performance-10 tests were conducted. For quality of life, the socioemotional and situational satisfaction domains of the population specific and validated PEQ (prosthesis evaluation questionnaire) were completed. Results Safety: Posturographic assessment revealed impairment between transfemoral amputees and non-amputees. Stumbles and semi-controlled falls decreased with Genium but were not significantly different. Four square step testing was significantly (p 0.05) improved from 12.2s(3.3) to 11.1s(3.4) for the C-Leg and Genium respectively. Function: Kinematic asymmetry was minimally different between knee conditions. The AMP mean(SD) scores while subjects used C-Leg was 40.8(3.6; 33-45) and 43.3(2.6) [p\u3c0.001]. PFP scores (cumulative), upper body function and endurance scores were improved with Genium compared with C-Leg at 9.1%(p=0.03), 8.7%(0.01) and 10.3%(0.04) respectively. Quality of Life: For quality of life, situational satisfaction favored Genium (p\u3c0.001) which included subject\u27s satisfaction with gait, training and quality of life in general. Conclusion C-Leg and Genium promote static weight bearing beyond asymmetric values reported in the literature. In terms of limits of stability, TFA\u27s are clearly impaired, primarily over the amputated side posteriorly however the Genium seems to enable posterior compensations that coincide with multi-directional stepping improvements. Anteriorly, the C-Leg\u27s toe triggering requirements seem to improve limits of stability but come at the cost of discomfort on ramp ascent. With regard to safety, it seems that both knee systems represent good options for the community ambulating TFA. The largest improvements with Genium were in the activities of daily living assessment; predominantly balance and upper body function. It seems that the combination of multi-direction stepping with starts and stops and stair ascent are key areas of improvement. In conclusion, the sensor array in the Genium knee prosthesis promotes improved function in activities of daily living. Specifically improved in this context were balance, endurance, multi-directional stepping, stair ascent and upper limb function in highly active transfemoral amputees

Instrumented Four Square Step Test in Adults with Transfemoral Amputation: Test-Retest Reliability and Discriminant Validity between Two Types of Microprocessor Knees

Technology-based outcomes have recently been proposed to complement the standard Four Square Step Test (FSST) by providing a decomposition of the sequences and information about the stepping pattern. A test-retest study and a randomized crossover design have been used to determine immediate test-retest reliability and to assess discriminant validity, in persons with a unilateral transfemoral amputation, for the parameters computed by an instrumented version of the Four Square Step Test. Twenty adults, independent and unlimited community ambulators, with a unilateral transfemoral amputation, performed two Four Square Step Tests on a pressure mat first with a microprocessor knee, then, a few weeks later with another one. One of these prosthetic knees was acknowledged to be superior and to provide functional improvement. Test-retest, intraclass correlation coefficients and minimal detectable change at 95% confidence level were calculated for each variable. Paired samples t-tests were then used to identify differences between the two microprocessor knee systems. The test-retest reliability of most outcome measures was good to excellent. Few variables showed a systematic difference and a trend to improve between test 1 and test 2. When comparing both microprocessor knees, significant differences in the expected direction were observed, with interpretation in accordance with a functional improvement. Importantly, we highlighted that various strategies to improve the performance in the test might complexify the interpretation of the most detailed measurement. The instrumented Four Square Step test provides reliable measures with satisfactory test-retest reliability and discriminant validity in persons with unilateral transfemoral amputation