Bilateral Transtibial Amputations Research Articles

Equivalent running leg lengths require prosthetic legs to be longer than biological legs during standing

We aimed to determine a method for prescribing a standing prosthetic leg length (ProsL) that results in an equivalent running biological leg length (BioL) for athletes with unilateral (UTTA) and bilateral transtibial amputations (BTTA). We measured standing leg length of ten non-amputee (NA) athletes, ten athletes with UTTA, and five athletes with BTTA. All athletes performed treadmill running trials from 3 m/s to their maximum speed. We calculated standing and running BioL and ProsL lengths and assessed the running-to-standing leg length ratio (Lratio) at three instances during ground contact: touchdown, mid-stance, and take-off. Athletes with UTTA had 2.4 cm longer standing ProsL than BioL length (p = 0.030), but their ProsL length were up to 3.3 cm shorter at touchdown and 4.1 cm shorter at mid-stance than BioL, at 3–11.5 m/s. At touchdown, mid-stance, and take-off, athletes with BTTA had 0.01–0.05 lower Lratio at 3 m/s (p < 0.001) and 0.03–0.07 lower Lratio at 10 m/s (p < 0.001) in their ProsL compared to the BioL of NA athletes. During running, ProsL were consistently shorter than BioL. To achieve equivalent running leg lengths at touchdown and take-off, athletes with UTTA should set their running-specific prosthesis height so that their standing ProsL length is 2.8–4.5% longer than their BioL length, and athletes with BTTA should set their running-specific prosthesis height so that their standing ProsL lengths are at least 2.1–3.9% longer than their presumed BioL length. Setting ProsL length to match presumed biological dimensions during standing results in shorter legs during running.

Fall Prevention Training for Service Members With an Amputation or Limb Salvage Following Lower Extremity Trauma.

Recent military conflicts have resulted in a significant number of lower extremity injuries to U.S. service members that result in amputation or limb preservation (LP) procedures. Service members receiving these procedures report a high prevalence and deleterious consequences of falls. Very little research exists to improve balance and reduce falls, especially among young active populations such as service members with LP or limb loss. To address this research gap, we evaluated the success of a fall prevention training program for service members with lower extremity trauma by (1) measuring fall rates, (2) quantifying improvements in trunk control, and (3) determining skill retention at 3 and 6 months after training. Forty-five participants (40 males, mean [±SD] age, 34 ± 8 years) with lower extremity trauma (20 with unilateral transtibial amputation, 6 with unilateral transfemoral amputation, 5 with bilateral transtibial amputation, and 14 with unilateral LP procedures) were enrolled. A microprocessor-controlled treadmill was used to produce task-specific postural perturbations which simulated a trip. The training was conducted over a 2-week period and consisted of six 30-minute sessions. The task difficulty was increased as the participant's ability progressed. The effectiveness of the training program was assessed by collecting data before training (baseline; repeated twice), immediately after training (0 month), and at 3 and 6 months post-training. Training effectiveness was quantified by participant-reported falls in the free-living environment before and after training. Perturbation-induced recovery step trunk flexion angle and velocity was also collected. Participants reported reduced falls and improved balance confidence in the free-living environment following the training. Repeated testing before training revealed that there were no pre-training differences in trunk control. The training program improved trunk control following training, and these skills were retained at 3 and 6 months after training. This study showed that task-specific fall prevention training reduced falls across a cohort of service members with diverse types of amputations and LP procedures following lower extremity trauma. Importantly, the clinical outcome of this effort (i.e., reduced falls and improved balance confidence) can lead to increased participation in occupational, recreational, and social activities and thus improved quality of life.

Retraction: Prosthetic shape, but not stiffness or height, affects the maximum speed of sprinters with bilateral transtibial amputations.

Retraction: Prosthetic shape, but not stiffness or height, affects the maximum speed of sprinters with bilateral transtibial amputations.

“Trench Foot” on the Banks of Lake Geneva: A Severe Case of Nonfreezing Cold Injury

Formerly known as “trench foot” or “immersion foot,” nonfreezing cold injury (NFCI) is a rare condition mainly seen among vulnerable groups. We report the case of a homeless male diagnosed with NFCI after having spent 2 days in rainy, cold weather. He presented with white, wrinkled feet and sensorimotor loss. Imaging revealed thrombosis of the leg arteries. No revascularization procedure was possible, and the patient developed soft tissue necrosis requiring bilateral transtibial amputation. Our case highlights the high morbidity linked with NFCI and the need for early recognition and treatment by medical health professionals along with the implementation of preventive measures.

Characteristics of Trunk Compensation Movements during Walking in People with Bilateral Transtibial Amputation: A Cross-sectional Study

ABSTRACTObjectives:The gait characteristics of people with bilateral transtibial amputation are not well understood. This study aimed to clarify changes in trunk lateral bending and the trunk flexion angle during walking in people with bilateral transtibial amputation.Methods:In this cross-sectional study, four participants with bilateral transtibial amputation who could walk without assistance (BTTA group) and ten able-bodied participants (control group) were recruited. The range of motion of trunk lateral bending, the trunk flexion angle, and other gait parameters during comfortable-speed and maximum-speed walking were measured using a three-dimensional motion analysis system and force plates. These parameters were compared between the amputees and the controls.Results:During maximum-speed walking, the BTTA group walked slower with a smaller trunk flexion angle (median, 1.75° vs. 4.79°, P=0.036) and greater double leg support time (0.18 vs. 0.12, P=0.008) when compared with the control group. The other parameters during maximum-speed walking were not significantly different between the two groups. During comfortable-speed walking, none of the parameters were significantly different between the two groups.Conclusions:Compensatory trunk flexion angle decreases markedly during maximum-speed walking in people with bilateral transtibial amputation. People with bilateral transtibial amputation may be changing the trunk flexion angle to walk faster. When evaluating gait compensation for people with bilateral transtibial amputation, trunk flexion angle may be an important index and maximum-speed walking is needed to detect the change in trunk flexion angle.

Clinical usability, reliability, and repeatability of noncontact scanners in measuring residual limb volume in persons with transtibial amputation.

In previous studies, noncontact 3D scanners were found to be the most reliable in measuring volume of the residual limb after a transtibial amputation (TTA). Meanwhile newly developed noncontact scanners became available to measure residual limb volume after TTA but should be tested for clinical usability and reliability. To determine the clinical usability, reliability, and repeatability of noncontact scanners in measuring residual limb volume in persons with a TTA. Original research report; repeated measurements. Three noncontact scanners (Rodin4D, Omega Tracer, and Biosculptor) were used to measure the residual limb volume on two occasions by two observers in 30 persons with an unilateral or bilateral TTA. Clinical usability was assessed as scores of the Post-Study System Usability Questionnaire, participant satisfaction (0-10 scale), and time to take the measurement. The usability score of the Omega Scanner 3D (123.4) and Rodin4D (121.3) was significantly better compared with the Biosculptor (117.8). Participant experience was equal for all. The residual variance was 8.4%, where participant and scanning system explained most of the error variance (80.7%). Repeatability coefficients of the systems were 16.5 cc (Omega Scanner 3D), 26.4 cc (Rodin4D), and 32.8 cc (Biosculptor). The time to perform the measurements was significantly longer (+80 seconds) for the Omega Scanner 3D. For measuring residual limb volume in TT amputees, Omega software (state version 12.2) combined with the Rodin4D scanner was more usable and reliable than the Rodin 4D or Biosculptor systems, when operated by staff with limited experience and training.

Prosthetic shape, but not stiffness or height, affects the maximum speed of sprinters with bilateral transtibial amputations.

Running-specific prostheses (RSPs) have facilitated an athlete with bilateral transtibial amputations to compete in the Olympic Games. However, the performance effects of using RSPs compared to biological legs remains controversial. Further, the use of different prosthetic configurations such as shape, stiffness, and height likely influence performance. We determined the effects of using 15 different RSP configurations on the maximum speed of five male athletes with bilateral transtibial amputations. These athletes performed sets of running trials up to maximum speed using three different RSP models (Freedom Innovations Catapult FX6, Össur Flex-Foot Cheetah Xtend and Ottobock 1E90 Sprinter) each with five combinations of stiffness category and height. We measured ground reaction forces during each maximum speed trial to determine the biomechanical parameters associated with different RSP configurations and maximum sprinting speeds. Use of the J-shaped Cheetah Xtend and 1E90 Sprinter RSPs resulted in 8.3% and 8.0% (p<0.001) faster maximum speeds compared to the use of the C-shaped Catapult FX6 RSPs, respectively. Neither RSP stiffness expressed as a category (p = 0.836) nor as kN·m-1 (p = 0.916) affected maximum speed. Further, prosthetic height had no effect on maximum speed (p = 0.762). Faster maximum speeds were associated with reduced ground contact time, aerial time, and overall leg stiffness, as well as with greater stance-average vertical ground reaction force, contact length, and vertical stiffness (p = 0.015 for aerial time, p<0.001 for all other variables). RSP shape, but not stiffness or height, influences the maximum speed of athletes with bilateral transtibial amputations.

Successful prosthetic rehabilitation and gait analysis of individual with bilateral transtibial amputation: A case study with comparison to able-bodied gait

Background: Intensive rehabilitation of individuals with bilateral lower limb loss poses a great challenge to both rehabilitation team and amputees themselves due to unavailability of a sound leg to provide stability in standing and gait. Although gait characteristics of individuals with unilateral transtibial amputations are well documented in the literature, very less is known about those with bilateral limb loss. Aim: To examine the gait characteristics of an individual with bilateral transtibial amputation (BTA) and its comparison with an able-bodied (AB). This study also provides a real-life presentation of successful prosthetic rehabilitation. Case content and methodology: Temporal–spatial, kinematic and kinetic gait parameters were analysed for a 45-year-old male individual with traumatic BTA using prosthesis in a motion analysis laboratory setting with force platform (BTS P-6000) and cameras with reflective markers (BTS SMART-DX6000). Findings and conclusion: Variances in many temporal–spatial, kinematic and kinetic parameters were observed. The findings of temporal–spatial parameters revealed that the individual with BTA walked with slower speed, lower cadence, shorter step lengths and wider step width compared to that of AB. Ankle dorsiflexion, stance knee flexion and swing hip hiking were reduced in an individual with BTA compared to AB. In kinetics, he demonstrated low peak ankle muscle power, increased muscle power amplitudes and phase duration at the hip and knee joints compared to AB individual. The combination of an intensive prosthetic rehabilitation led to completely independent and remarkable degree of functional ambulation.

Risk Factors for Falls in Individuals With Lower Extremity Amputations During the Pre-Prosthetic Phase: A Retrospective Cohort Study.

Falls in individuals with lower limb amputations (LLAs) pose significant health concerns. The literature is limited regarding falls during the preprosthetic phase of rehabilitation for persons with LLAs. To determine the incidence of falls and identify factors associated with falls during the preprosthetic recovery phase. Retrospective chart audit. Inpatient rehabilitation program. Four hundred forty individuals with LLAs (age ± SD = 61.93 ± 14.53 years, 73.18% male) who attended inpatient rehabilitation from 26 July 2011 to 21 August 2017. Not applicable. The number of self-reported falls was recorded from the time of surgery to admission for inpatient rehabilitation. Outcomes of interest were any fall (1+ fall) and recurrent falls (2+ falls). A retrospective chart audit was performed on consecutive admissions to an inpatient rehabilitation program. The incidence of falls was 8.37 per 1000 patient-days. Falls were sustained by 60.9% of the sample. Unilateral transtibial amputation was independently associated with an increased risk of recurrent falls (relative risk [RR] 1.59, 95% confidence interval [CI] 1.13-2.23, P = .008). Diabetes mellitus was independently associated with an increased risk of any fall (RR 1.18, 95% CI 1.01-.38, P = .03). Finally, bilateral transtibial amputation was independently associated with a reduced risk of any fall (RR 0.59, 95% CI 0.39-0.90, P = .014). Consistent with the current literature, diabetes mellitus and a unilateral transtibial amputation were risk factors for falling, whereas a bilateral transtibial amputation and increasing age presented new findings as factors associated with decreased falling. III.

Prosthetic Limb User Experiences With Crossover Feet: A Pilot Focus Group Study to Explore Outcomes That Matter

ABSTRACT Introduction Many different prosthetic feet are available to meet the diverse needs of people with lower-limb amputation. Current methods used to assess comparative effectiveness of prosthetic feet may not align with outcomes that are most important to people with lower-limb amputation. User participation in qualitative research is one approach to guide selection of outcome measures for clinical practice and quantitative research studies. This pilot study examined outcomes of importance to people who have used both energy storing and crossover prosthetic feet. Materials and Methods An in-person focus group of people with lower-limb amputation was conducted. Inclusion criteria were as follows: 18 years of age or older, lower-limb amputation, previous use of an energy storing foot and crossover foot, and a minimum of 1 year prosthesis use. Results Five participants with lower-limb amputation (4 males/1 female), aged 41 to 59 years (mean, 45.6 ± 7.7 years), participated in the focus group. Three participants had unilateral transtibial amputations; one had bilateral transtibial amputations; and another had bilateral involvement with a transtibial and partial-foot amputation. All participants reported daily use of a prosthesis (mean, 15.2 ± 1.1 hours). Three categories of themes arose from this focus group: direct outcomes, external influences, and indirect outcomes. Direct outcomes included balance and stability, endurance and sustained gait quality, and naturalness. External influences included peer and prosthetist interactions. Indirect outcomes included increased confidence and expanded mobility. Outcome measures available to assess identified constructs were suggested. Conclusions Engagement of prosthesis users through qualitative research methods can inform the choice of outcome measures used to assess clinical outcomes or evaluate the effectiveness of prosthetic devices.

Athletes With Versus Without Leg Amputations: Different Biomechanics, Similar Running Economy.

Athletes with transtibial amputations use carbon-fiber prostheses to run. Compared with biological legs, these devices differ in structure and function, and consequently yield affected leg running biomechanics that are theoretically more economical than those of nonamputees. However, experimental data indicate that athletes with unilateral and bilateral transtibial amputations exhibit running economy values that are well within the range of nonamputee values.

How do prosthetic stiffness, height and running speed affect the biomechanics of athletes with bilateral transtibial amputations?

Limited available information describes how running-specific prostheses and running speed affect the biomechanics of athletes with bilateral transtibial amputations. Accordingly, we quantified the effects of prosthetic stiffness, height and speed on the biomechanics of five athletes with bilateral transtibial amputations during treadmill running. Each athlete performed a set of running trials with 15 different prosthetic model, stiffness and height combinations. Each set of trials began with the athlete running on a force-measuring treadmill at 3 m s-1, subsequent trials incremented by 1 m s-1 until they achieved their fastest attainable speed. We collected ground reaction forces (GRFs) during each trial. Prosthetic stiffness, height and running speed each affected biomechanics. Specifically, with stiffer prostheses, athletes exhibited greater peak and stance average vertical GRFs (β = 0.03; p < 0.001), increased overall leg stiffness (β = 0.21; p < 0.001), decreased ground contact time (β = -0.07; p < 0.001) and increased step frequency (β = 0.042; p < 0.001). Prosthetic height inversely associated with step frequency (β = -0.021; p < 0.001). Running speed inversely associated with leg stiffness (β = -0.58; p < 0.001). Moreover, at faster running speeds, the effect of prosthetic stiffness and height on biomechanics was mitigated and unchanged, respectively. Thus, prosthetic stiffness, but not height, likely influences distance running performance more than sprinting performance for athletes with bilateral transtibial amputations.

Is the Metabolic Cost of Running Different for Athletes with Unilateral Versus Bilateral Transtibial Amputations?

Is the Metabolic Cost of Running Different for Athletes with Unilateral Versus Bilateral Transtibial Amputations?

Reduced prosthetic stiffness lowers the metabolic cost of running for athletes with bilateral transtibial amputations.

Inspired by the springlike action of biological legs, running-specific prostheses are designed to enable athletes with lower-limb amputations to run. However, manufacturer's recommendations for prosthetic stiffness and height may not optimize running performance. Therefore, we investigated the effects of using different prosthetic configurations on the metabolic cost and biomechanics of running. Five athletes with bilateral transtibial amputations each performed 15 trials on a force-measuring treadmill at 2.5 or 3.0 m/s. Athletes ran using each of 3 different prosthetic models (Freedom Innovations Catapult FX6, Össur Flex-Run, and Ottobock 1E90 Sprinter) with 5 combinations of stiffness categories (manufacturer's recommended and ± 1) and heights (International Paralympic Committee's maximum competition height and ± 2 cm) while we measured metabolic rates and ground reaction forces. Overall, prosthetic stiffness [fixed effect (β) = 0.036; P = 0.008] but not height (P ≥ 0.089) affected the net metabolic cost of transport; less stiff prostheses reduced metabolic cost. While controlling for prosthetic stiffness (in kilonewtons per meter), using the Flex-Run (β = -0.139; P = 0.044) and 1E90 Sprinter prostheses (β = -0.176; P = 0.009) reduced net metabolic costs by 4.3-4.9% compared with using the Catapult prostheses. The metabolic cost of running improved when athletes used prosthetic configurations that decreased peak horizontal braking ground reaction forces (β = 2.786; P = 0.001), stride frequencies (β = 0.911; P < 0.001), and leg stiffness values (β = 0.053; P = 0.009). Remarkably, athletes did not maintain overall leg stiffness across prosthetic stiffness conditions. Rather, the in-series prosthetic stiffness governed overall leg stiffness. The metabolic cost of running in athletes with bilateral transtibial amputations is influenced by prosthetic model and stiffness but not height.NEW & NOTEWORTHY We measured the metabolic rates and biomechanics of five athletes with bilateral transtibial amputations while running with different prosthetic configurations. The metabolic cost of running for these athletes is minimized by using an optimal prosthetic model and reducing prosthetic stiffness. The metabolic cost of running was independent of prosthetic height, suggesting that longer legs are not advantageous for distance running. Moreover, the in-series prosthetic stiffness governs the leg stiffness of athletes with bilateral leg amputations.

Low-Cost Methodology for Skin Strain Measurement of a Flexed Biological Limb.

The purpose of this manuscript is to compute skin strain data from a flexed biological limb, using portable, inexpensive, and easily available resources. We apply and evaluate this approach on a person with bilateral transtibial amputations, imaging left and right residual limbs in extended and flexed knee postures. We map 3-D deformations to a flexed biological limb using freeware and a simple point-and-shoot camera. Mean principal strain, maximum shear strain, as well as lines of maximum, minimum, and nonextension are computed from 3-D digital models to inform directional mappings of the strain field for an unloaded residual limb. Peak tensile strains are ∼0.3 on the anterior surface of the knee in the proximal region of the patella, whereas peak compressive strains are ∼ -0.5 on the posterior surface of the knee. Peak maximum shear strains are ∼0.3 on the posterior surface of the knee. The accuracy and precision of this methodology are assessed for a ground-truth model. The mean point location distance is found to be 0.08 cm, and the overall standard deviation for point location difference vectors is 0.05 cm. This low-cost and mobile methodology may prove critical for applications such as the prosthetic socket interface where whole-limb skin strain data are required from patients in the field outside of traditional, large-scale clinical centers. Such data may inform the design of wearable technologies that directly interface with human skin.

Poster 46 Multiple Amputations Including Bilateral Transtibial Amputations in a 29-Year-Old Female After Suffering Placental Abruption, GBS Septicemia and DIC: ACase Report.

Poster 46 Multiple Amputations Including Bilateral Transtibial Amputations in a 29-Year-Old Female After Suffering Placental Abruption, GBS Septicemia and DIC: ACase Report.

Impact of Physical Therapy for a Patient with Multiple Limb Amputations Secondary to Legionnaires' Disease: A Case Report

ABSTRACT Background and Purpose Collaboration between the physical therapist and prosthetist is essential for patients with any type of amputation. This case report describes a patient with multiple limb amputations due to medical complications resulting from community acquired Legionnaires' disease (LD). The physical therapy evaluation, examination, diagnosis, interventions, and outcomes along with collaboration with the prosthetist are discussed. Case Description A 55-year-old previously healthy male contracted LD and subsequently developed multiple medical complications in acute care. This resulted in left transradial and bilateral transtibial amputations due to hypotension-induced ischemia from sepsis. A 2-month course of inpatient rehabilitation is described, including changes in functional status and progression to safe discharge home. Outcomes Physical therapy interventions resulted in an improvement from total assist for all functional mobility to ambulating at a standby assist level with bilateral lower limb and left upper limb prosthesis. He improved his 10-m walk test score from 0.07 to 0.60 m/s, 6-minute walk test to 133 m, and timed up and go test to 47 seconds. Discussion A comprehensive list of physical therapy interventions needs to be included for successful rehabilitation of a medically complex patient with multiple limb amputations. Collaboration with the prosthetist is inherent and critical. Future research may include a series of case reports or a study using practice-based evidence. This would allow for more associations to be made regarding interventions for patients with multiple limb amputations.

Effect of running speed and leg prostheses on mediolateral foot placement and its variability.

This study examined the effects of speed and leg prostheses on mediolateral (ML) foot placement and its variability in sprinters with and without transtibial amputations. We hypothesized that ML foot placement variability would: 1. increase with running speed up to maximum speed and 2. be symmetrical between the legs of non-amputee sprinters but asymmetrically greater for the affected leg of sprinters with a unilateral transtibial amputation. We measured the midline of the body (kinematic data) and center of pressure (kinetic data) in the ML direction while 12 non-amputee sprinters and 7 Paralympic sprinters with transtibial amputations (6 unilateral, 1 bilateral) ran across a range of speeds up to maximum speed on a high-speed force measuring treadmill. We quantified ML foot placement relative to the body’s midline and its variability. We interpret our results with respect to a hypothesized relation between ML foot placement variability and lateral balance. We infer that greater ML foot placement variability indicates greater challenges with maintaining lateral balance. In non-amputee sprinters, ML foot placement variability for each leg increased substantially and symmetrically across speed. In sprinters with a unilateral amputation, ML foot placement variability for the affected and unaffected leg also increased substantially, but was asymmetric across speeds. In general, ML foot placement variability for sprinters with a unilateral amputation was within the range observed in non-amputee sprinters. For the sprinter with bilateral amputations, both affected legs exhibited the greatest increase in ML foot placement variability with speed. Overall, we find that maintaining lateral balance becomes increasingly challenging at faster speeds up to maximum speed but was equally challenging for sprinters with and without a unilateral transtibial amputation. Finally, when compared to all other sprinters in our subject pool, maintaining lateral balance appears to be the most challenging for the Paralympic sprinter with bilateral transtibial amputations.

Ambulation and independence among Veterans with nontraumatic bilateral lower-limb loss.

In describing functional outcomes and independent living in a cohort of bilateral major amputees, we sought to provide current estimates of function and independence after a second major amputation in an elderly Veteran population with peripheral arterial disease and/or diabetes. After retrospectively reviewing and excluding the electronic health records of those failing to meet the inclusion criteria, we identified 40 patients with a history of unilateral major amputation who underwent a second major amputation during the defined study period. Of these, 43% (17) were bilateral transfemoral amputations (TFAs); bilateral transtibial amputations (TTAs) and TFA-TTA accounted for the rest (33% and 25%, respectively). Of the 19 (48%) patients who were ambulatory prior to bilateral amputation, only 2 (11%) remained ambulatory after the second amputation, while 17 (89%) patients lost ambulatory capabilities. Compared with those who were </=65 yr, those between 66 and 79 yr were 18% less likely to ambulate precontralateral amputation (p = 0.03). All patients with bilateral TFA were nonambulatory. Independence postcontralateral amputation decreased from 88% (35) to 53% (21). When data were available (58%), pre and post Functional Independence Measure scores showed a decrease in 74% of patients, while 22% showed an increase. In conclusion, bilateral lower-limb amputation among dysvascular Veterans is highly associated with a loss of ambulation.

Poster 11 Prehabilitation for Patient with Recalcitrant Foot and Ankle Ulcers due to Werner's Syndrome Prior to Bilateral Transtibial Amputations: A Case Report

PM&RVolume 6, Issue 9S p. S185-S185 Friday Poster Presentations - Poster Hall Poster 11 Prehabilitation for Patient with Recalcitrant Foot and Ankle Ulcers due to Werner's Syndrome Prior to Bilateral Transtibial Amputations: A Case Report Jairon D. Downs MD, Jairon D. Downs MD School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United StatesSearch for more papers by this authorMichael Y. Lee MD, MHA, Michael Y. Lee MD, MHA School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United StatesSearch for more papers by this author Jairon D. Downs MD, Jairon D. Downs MD School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United StatesSearch for more papers by this authorMichael Y. Lee MD, MHA, Michael Y. Lee MD, MHA School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United StatesSearch for more papers by this author First published: 29 September 2014 https://doi.org/10.1016/j.pmrj.2014.08.412Citations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume6, Issue9SSeptember 2014Pages S185-S185 RelatedInformation