Post-transplant survival after normothermic regional perfusion versus direct procurement and perfusion in donation after circulatory determination of death in heart transplantation

BACKGROUND

Since 2019, the annual transplantation rate of hearts donated following circulatory death (DCD) has increased significantly in the United States. The 2 major heart procurement techniques following circulatory death are direct procurement and perfusion (DPP) and normothermic regional perfusion (NRP). Post-transplant survival for heart recipients has not been compared between these 2 techniques.

METHODS

This observational study uses data on adult heart transplants from donors after circulatory death from January 1, 2019 to December 31, 2021 in the Scientific Registry of Transplant Recipients. We identified comparable transplant cases across procurement types using propensity-score matching and measured the association between procurement technique and 1-year post-transplant survival using Kaplan-Meier and Cox proportional hazards model stratefied by matching pairs.

RESULTS

Among 318 DCD heart transplants, 216 (68%) were procured via DPP, and 102 (32%) via NRP. Among 22 transplant centers that accepted circulatory-death donors, 3 used NRP exclusively, and 5 used both procurement techniques. After propensity-score matching on recipient and donor factors, there was no significant difference in 1-year post-transplant survival (93.1% for NRP vs 91.1% for DPP, p = 0.79) between procurement techniques.

CONCLUSIONS

NRP and DPP procurements are associated with similar 1-year post-transplant survival. If NRP is ethically permissible and improves outcomes for abdominal organs, it should be the preferred procurement technique for DCD hearts.

Knowledge gaps in heart and lung donation after the circulatory determination of death: Report of a workshop of the National Heart, Lung, and Blood Institute

In a workshop sponsored by the U.S. National Heart, Lung, and Blood Institute, experts identified current knowledge gaps and research opportunities in the scientific, conceptual, and ethical understanding of organ donation after the circulatory determination of death and its technologies. To minimize organ injury from warm ischemia and produce better recipient outcomes, innovative techniques to perfuse and oxygenate organs postmortem in situ, such as thoracoabdominal normothermic regional perfusion, are being implemented in several medical centers in the US and elsewhere. These technologies have improved organ outcomes but have raised ethical and legal questions. Re-establishing donor circulation postmortem can be viewed as invalidating the condition of permanent cessation of circulation on which the earlier death determination was made and clamping arch vessels to exclude brain circulation can be viewed as inducing brain death. Alternatively, TA-NRP can be viewed as localized in-situ organ perfusion, not whole-body resuscitation, that does not invalidate death determination. Further scientific, conceptual, and ethical studies, such as those identified in this workshop, can inform and help resolve controversies raised by this practice.

Quality measures in pre-liver transplant care by the Practice Metrics Committee of the American Association for the Study of Liver Diseases

The liver transplantation (LT) evaluation and waitlisting process is subject to variations in care that can impede quality. The American Association for the Study of Liver Diseases (AASLD) Practice Metrics Committee (PMC) developed quality measures and patient-reported experience measures along the continuum of pre-LT care to reduce care variation and guide patient-centered care. Following a systematic literature review, candidate pre-LT measures were grouped into 4 phases of care: referral, evaluation and waitlisting, waitlist management, and organ acceptance. A modified Delphi panel with content expertise in hepatology, transplant surgery, psychiatry, transplant infectious disease, palliative care, and social work selected the final set. Candidate patient-reported experience measures spanned domains of cognitive health, emotional health, social well-being, and understanding the LT process. Of the 71 candidate measures, 41 were selected: 9 for referral; 20 for evaluation and waitlisting; 7 for waitlist management; and 5 for organ acceptance. A total of 14 were related to structure, 17 were process measures, and 10 were outcome measures that focused on elements not typically measured in routine care. Among the patient-reported experience measures, candidates of LT rated items from understanding the LT process domain as the most important. The proposed pre-LT measures provide a framework for quality improvement and care standardization among candidates of LT. Select measures apply to various stakeholders such as referring practitioners in the community and LT centers. Clinically meaningful measures that are distinct from those used for regulatory transplant reporting may facilitate local quality improvement initiatives to improve access and quality of care.

Unspoken Truths: Mental Health Among Academic Surgeons

OBJECTIVE

To characterize the current state of mental health within the surgical workforce in the United States.

BACKGROUND

Mental illness and suicide is a growing concern in the medical community; however, the current state is largely unknown.

METHODS

Cross-sectional survey of the academic surgery community assessing mental health, medical error, and suicidal ideation. The odds of suicidal ideation adjusting for sex, prior mental health diagnosis, and validated scales screening for depression, anxiety, post-traumatic stress disorder (PTSD), and alcohol use disorder were assessed.

RESULTS

Of 622 participating medical students, trainees, and surgeons (estimated response rate=11.4%-14.0%), 26.1% (141/539) reported a previous mental health diagnosis. In all, 15.9% (83/523) of respondents screened positive for current depression, 18.4% (98/533) for anxiety, 11.0% (56/510) for alcohol use disorder, and 17.3% (36/208) for PTSD. Medical error was associated with depression (30.7% vs. 13.3%, P <0.001), anxiety (31.6% vs. 16.2%, P =0.001), PTSD (12.8% vs. 5.6%, P =0.018), and hazardous alcohol consumption (18.7% vs. 9.7%, P =0.022). Overall, 13.2% (73/551) of respondents reported suicidal ideation in the past year and 9.6% (51/533) in the past 2 weeks. On adjusted analysis, a previous history of a mental health disorder (aOR: 1.97, 95% CI: 1.04-3.65, P =0.033) and screening positive for depression (aOR: 4.30, 95% CI: 2.21-8.29, P <0.001) or PTSD (aOR: 3.93, 95% CI: 1.61-9.44, P =0.002) were associated with increased odds of suicidal ideation over the past 12 months.

CONCLUSIONS

Nearly 1 in 7 respondents reported suicidal ideation in the past year. Mental illness and suicidal ideation are significant problems among the surgical workforce in the United States.

Uterus transplantation: what the world's religions have to say

Uterus transplantation (UTx) has evolved from a purely experimental procedure to a clinical treatment option available outside the clinical trial context, offering women with absolute uterine-factor infertility an opportunity to experience pregnancy. As UTx becomes better established and more widely known and performed, it is likely to be sought out by geographically and culturally diverse patients, particularly those whose religious beliefs impose barriers to other paths to achieve parenthood, such as gestational surrogacy and adoption. Many religions do not currently have official positions on UTx, meaning that clinicians involved in screening candidates can expect questions about how the UTx process aligns with various religious beliefs. This article provides a broad background on the current positions major world religions have taken on UTx (or its components) and the alternative paths to parenthood of gestational surrogacy and adoption. It is intended to help clinicians communicate the information necessary for individuals interested in uterus donation or transplantation to determine-in consultation with their spiritual advisors or religious authorities when needed-how these options align with religious beliefs or teachings.

The American Society of Transplant Surgeons Consensus Statement on Normothermic Regional Perfusion

On June 3, 2023, the American Society of Transplant Surgeons convened a meeting in San Diego, California to (1) develop a consensus statement with supporting data on the ethical tenets of thoracoabdominal normothermic regional perfusion (NRP) and abdominal NRP; (2) provide guidelines for the standards of practice that should govern thoracoabdominal NRP and abdominal NRP; and (3) develop and implement a central database for the collection of NRP donor and recipient data in the United States. National and international leaders in the fields of neuroscience, transplantation, critical care, NRP, Organ Procurement Organizations, transplant centers, and donor families participated. The conference was designed to focus on the controversial issues of neurological flow and function in donation after circulatory death donors during NRP and propose technical standards necessary to ensure that this procedure is performed safely and effectively. This article discusses major topics and conclusions addressed at the meeting.

A cost comparison of liver acquisition fees for donation after circulatory death versus donation after brain death donors

Donation after circulatory death (DCD) donors now represent over 30% of the deceased donor pool in the United States. Compared to donation after brain death, DCD is less likely to result in transplantation. For each potential donor whose organs cannot be utilized for transplantation (ie, dry run), fees are associated with the attempted donation, which add to the overall costs of organ acquisition. To better characterize the true costs of DCD liver acquisition, we performed a cost comparison of the fees associated with organ acquisition for DCD versus donation after brain death at a single transplant institute that comprises 2 liver transplant centers. Cost, recipient, and transportation data for all cases, including fees associated with liver acquisition from July 1, 2019, to October 31, 2021, were collected. We found that the total cost of DCD liver acquisition per liver transplant was $15,029 more than that for donation after brain death donation, with 18% of the costs of the DCD transplant attributed to dry runs. Overall, the costs associated with DCD transplantation accounted for 34.5% of the total organ acquisition costs; however, DCD transplantation accounted for 30.3% of the transplantation volume. Because the expansion of DCD is essential to increasing the availability of liver grafts for transplantation, strategies need to be implemented to decrease the costs associated with dry runs, including using local recovery, transferring donors to hospitals close to transplant centers, and performing more prerecovery organ analysis. Moreover, these strategies are needed to ensure that financial disincentives to DCD procurement and utilization do not reverse the gains made by expanding the organ donor pool using machine perfusion technologies.

Living uterus donors' perceptions of decision-making and informed consent: a qualitative study of the Dallas Uterus Transplant Study participants

Uterus transplantation is a growing field, but little is known about living uterus donors' perceptions of informed consent or their decision-making processes. This study used semistructured interviews to collect information regarding uterus donors' experiences with uterus donation, perceptions of the informed consent process, and information on how they decided to pursue uterus donation. Interviews were coded for thematic analysis. Three major themes emerged in this study. First, the decision-making process was based on individuals' motivations, rationale, and considerations of alternative contributions to help other women with infertility. Second, participants described how they felt about the process of informed consent, their decision-making processes, and how their experiences compared with their expectations. Third, participants discussed how uterus donation was a valuable experience. This study found that living uterus donors are motivated to give another woman the opportunity to experience pregnancy and childbirth. They were satisfied with the informed consent process, their experiences were in line with their expectations, and the value of uterus donation was associated with the act of donation itself. Our findings suggest that living donor uterus programs should develop robust informed consent processes that provide detailed information about uterus donation and encourage shared decision-making with potential uterus donors.

Living Donor Ethics and Uterus Transplantation

This article provides an in-depth ethical analysis of living donor uterus transplantation, incorporating clinical, psychological, and qualitative study data into the discussion. Although the concept of living organ donors as patients in their own right has not always been present in the field of transplantation, this conceptualization informs the framework for living donor ethics that we apply to living uterus donation. This framework takes root in the principles of research ethics, which include respect for persons, beneficence, and justice. It incorporates an analysis based on eight potential vulnerabilities of living donors: capacitational, juridic, deferential, social, medical, situational, allocational, and infrastructural. Finally, it recognizes that special relationships-such as that of the living donor advocate with the potential donor-require special responsibilities, including identifying vulnerabilities and engaging donors in a shared decision-making process. Directed and non-directed uterus donors require separate ethical analyses because their different relationships with recipients will influence the types of vulnerabilities, they are subject to as well as the potential benefits they may gain from donation.

Applying the ethical framework for donation after circulatory death to thoracic normothermic regional perfusion procedures

The novel approach of thoracic normothermic regional perfusion (TA-NRP) for in-situ preservation of organs prior to removal presents a new series of ethical questions about donation after circulatory determination of death (DCD) procedures. This manuscript describes the framework used for the analysis of ethical acceptability of DCD donation and analyzes the specific practice of TA-NRP DCD within that framework to demonstrate that TA-NRP DCD can be performed within the ethical boundaries of DCD donation. We argue that TA-NRP DCD organ procurements meet the ethical standards of informed consent, non-maleficence, adherence to the dead donor rule, and irreversibility, and as such, are ethically acceptable. We also describe the potential benefits of TA-NRP DCD procedures that result from higher organ yields and better recipient outcomes. Finally, we call for open and transparent support of TA-NRP DCD by professional organizations as a necessary cornerstone for the advancement of TA-NRP DCD procedures.

The Future of Uterus Transplantation: Cost, Regulations, and Outcomes

Uterus transplantation (UTx) has evolved rapidly since technical success was first demonstrated, and is now practiced worldwide, using both living and deceased donors. As UTx transitions from an experimental to widely available standard clinical procedure, new challenges and questions are becoming more urgent. These include issues of cost and coverage, the establishment of guidelines and registries to ensure quality of care and monitor outcomes, regulatory oversight (including for the allocation organs from deceased donors), and the extent to which indications for UTx should be expanded.

The Ethical Evolution of Uterus Transplantation From Concept to Clinical Procedure

Uterus transplantation (UTx) offers women with absolute uterine factor infertility a path to motherhood that enables them to carry their own pregnancy. Debates about the ethics of UTx have evolved in tandem with its clinical evolution: clinical trials have provided evidence regarding risks and benefits to donors and recipients that were initially uncertain; technical advances have altered the balance between risks and benefits; and the experiences of donors and recipients has revealed questions that were not anticipated. As UTx transitions to a clinical procedure, questions remain about long-term risks and benefits, applications beyond carrying a pregnancy, and cost and access.

Utilization of a SARS-CoV-2-positive donor for liver transplantation

Liver transplantation rates have been negatively affected by the pandemic caused by coronavirus disease 2019 (COVID-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Current practice in the liver transplant community is to avoid utilizing SARS-CoV-2-positive donors for liver transplantation unless there is a compelling reason such as recipient illness severity. In this case, we report the use of a donor who had a positive exposure to and symptom history for COVID-19 and tested positive for SARS-CoV-2 on admission for a liver transplant recipient with primary sclerosing cholangitis and a Model of End-Stage Liver Disease score of 23 with no known COVID-19 exposures. We focus on the decision to accept this particular organ, as well as the discussion with the recipient about the unknowns of disease transmission and risk associated with this donor. The current case argues that transplant programs should begin to consider low-risk donors with positive SARS-CoV-2 testing for recipients who have the potential to benefit from liver transplantation, which may not only be those with the most severe illness.

The journey from infertility to uterus transplantation: A qualitative study of the perspectives of participants in the Dallas Uterus Transplant Study

OBJECTIVE

To assess how absolute uterine factor infertility affects women who undergo uterus transplantation, how uterus transplantation impacts women with absolute uterine factor infertility and how uterus transplant recipients view uterus transplantation in terms of their reproductive autonomy.

DESIGN

Qualitative semi-structured interview study.

SETTING

Uterus transplant programme in a large academic medical centre in the USA.

POPULATION/SAMPLE

Twenty one uterus transplant recipients.

METHODS

A medical chart review was conducted to collect patient demographic information and clinical outcomes. Semi-structured interviews collected information regarding participants' experience.

MAIN OUTCOME MEASURE(S)

The outcomes of interest were participants' experience of infertility, experience with uterus transplantation and general perceptions of uterus transplantation.

RESULTS

Six participants were pregnant (one with a second child), six had experienced early graft failure and removal, five had delivered a healthy baby, and four had a viable graft and were awaiting embryo transfer. The primary themes identified were: the negative impact of absolute uterine factor infertility diagnosis on psychological wellbeing, relationships and female identity; the positive impact of uterus transplantation on healing the emotional scars of absolute uterine factor infertility, female identity and value of research trial participation and the perception of uterus transplantation as an expansion of reproductive autonomy. All participants reported that uterus transplantation was worthwhile, regardless of individual outcome.

CONCLUSION

Absolute uterine factor infertility has a negative impact on women from a young age, affects multiple relationships and challenges female identity. Uterus transplantation helps to reverse this impact, transforming women's life narrative of infertility and enhancing female identity.

TWEETABLE ABSTRACT

Absolute uterine factor infertility (AUFI) adversely affects women. Uterus transplantation helps mitigate the negative impact of AUFI, by transforming women's life narratives of infertility and enhancing female identity.

Cost Analysis of Liver Acquisition Fees Before and After Acuity Circle Policy Implementation

Importance

Acuity circles (AC) liver allocation policy was implemented to eliminate donor service area geographic boundaries from liver allocation and to decrease variability in median Model of End-stage Liver Disease (MELD) score at transplant and wait list mortality. However, the broader sharing of organs was also associated with more flights for organ procurements and higher costs associated with the increase in flights.

Objective

To determine whether the costs associated with liver acquisition changed after the implementation of AC allocation.

Design, Setting, and Participants

This single-center cost comparison study analyzed fees associated with organ acquisition before and after AC allocation implementation. The cost data were collected from a single transplant institute with 2 liver transplant centers, located 30 miles apart, in different donation service areas. Cost, recipient, and transportation data for all cases that included fees associated with liver acquisition from July 1, 2019, to October 31, 2020, were collected.

Exposures

Primary liver offer acceptance with associated organ procurement organization or charter flight fees.

Main Outcomes and Measures

Specific fees (organ acquisition, surgeon, import, and charter flight fees) and total fees per donor were collected for all accepted liver donors with at least 1 associated fee during the study period.

Results

Of 213 included donors, 171 were used for transplant; 90 of 171 (52.6%) were male, and the median (interquartile range) age of donors was 41.0 (30.0-52.8) years in the pre-AC period and 36.9 (24.0-48.8) years in the post-AC period. There was no significant difference in the post-AC compared with pre-AC period in median (range) MELD score (24 [8-40] vs 25 [6-40]; P = .27) or median (range) match run sequence (15 [1-3951] vs 10 [1-1138]; P = .31), nor in mean (SD) distance traveled (155.83 [157.00] vs 140.54 [144.33] nautical miles; P = .32) or percentage of donors requiring flights (58.5% [69 of 118] vs 56.8% [54 of 95]; P = .82). However, costs increased significantly in the post-AC period: total cost increased 16% per accepted donor (mean [SD] of $52 966 [13 278] vs $45 725 [9300]; P < .001) and 55% per declined donor (mean [SD] of $15 865 [3942] vs $10 217 [4853]; P < .001). Contributing factors included more than 2-fold increases in the proportions of donors incurring import fees (31.4% [37 of 118] vs 12.6% [12 of 95]; P = .002) and surgeon fees (19.5% [23 of 118] vs 9.5% [9 of 95]; P = .05), increased acquisition fees (10% increase; mean [SD] of $43 860 [3266] vs $39 980 [2236]; P < .001), and increased flight expenses (43% increase; mean [SD] of $12 904 [6066] vs $9049 [5140]; P = .002).

Conclusions and Relevance

The unintended consequences of implementing broader sharing without addressing organ acquisition fees to account for increased importation between organ procurement organizations must be remedied to contain costs and ensure viability of transplant programs.

Psychological Characteristics of Recipients Pretransplantation in the Dallas UtErus Transplant Study (DUETS)

INTRODUCTION

Uterus transplantation is now a viable option for fertility treatment for women with absolute uterine factor infertility. Psychological assessment is recommended as a part of the perioperative evaluation process.

RESEARCH OBJECTIVE

The purpose of this study was to examine the psychological characteristics and mental health history of the 20 women who participated in the Dallas UtErus Transplant Study (DUETS) trial.

DESIGN

This retrospective observational descriptive study was part of a prospective clinical trial. Prior to transplant, 20 women completed a clinical psychological interview, 19 of whom also completed psychological assessment measures including the Hospital Anxiety and Depression Scale, Patient Health Questionnaire 9 item, Generalized Anxiety Disorder 7 item, PTSD Checklist for DSM-5, 36-Item Short Form, Connor-Davidson Resilience Scale 10 item, and Dyadic Adjustment Scale.

RESULTS

Women who participated in the trial had high health-related quality of life and minimal psychological history, with most reporting psychological distress associated with their initial infertility diagnosis (N = 13). None of the participants endorsed psychological distress to meet clinical concerns on the psychological measures used. Satisfaction with relationship adjustment with their partners was also high.

CONCLUSIONS

Women with absolute uterine factor infertility who underwent uterus transplant demonstrated low psychological distress on assessment measures, were resilient, had high health related quality of life, and strong satisfaction with the quality of relationships with their partners. Although some women reported either current or past psychological diagnosis, most reported psychological distress that occurred at the time of the infertility diagnosis and appeared to resolve over time.

Uterus transplantation-questions and answers about the procedure that is expanding the field of solid organ transplantation

Uterus transplant is a new and rapidly evolving field of solid organ transplantation designed to help women with absolute uterine-factor infertility who desire to carry their own pregnancies. The advent of this procedure and human clinical trials of uterus transplantation have raised technical, clinical, and ethical questions. We address several questions about uterus transplantation based on available literature and the clinical experience at Baylor University Medical Center, which has the largest uterus transplant program in the United States.

Two Cases of Pregnancy Following Uterine Transplant: An Ethical Analysis

Uterine factor infertility (UFI) affects 1-5% of women of reproductive age, and uterus transplantation is the only option available to these women for carrying a pregnancy. The ethical analysis of uterus transplantation focuses on the value and experience of pregnancy in recipients; to date, however, no personal experiences with pregnancy after uterus transplantation have been published. The authors share the stories of two of our uterus transplant recipients, obtained through semi-structured, in-person interviews. The interview questions focused on the recipients' experiences during pregnancy. We report the cases as the interwoven narratives of the two women's pregnancies and their perceptions of the value of gestation.

Two Cases of Pregnancy Following Uterine Transplant: An Ethical Analysis

Uterine factor infertility (UFI) affects 1-5% of women of reproductive age, and uterus transplantation is the only option available to these women for carrying a pregnancy. The ethical analysis of uterus transplantation focuses on the value and experience of pregnancy in recipients; to date, however, no personal experiences with pregnancy after uterus transplantation have been published. The authors share the stories of two of our uterus transplant recipients, obtained through semi-structured, in-person interviews. The interview questions focused on the recipients' experiences during pregnancy. We report the cases as the interwoven narratives of the two women's pregnancies and their perceptions of the value of gestation.

Decision making and informed consent in uterus transplant recipients: A mixed-methods study of the Dallas uterus transplant study (DUETS) participants

BACKGROUND

Uterus transplantation (Utx) has achieved clinical success but little is known about motivations and experiences of UTx recipients.

METHODS

We conducted semi-structured interviews with 20 UTx recipients in addition to collecting quantitative demographic and clinical data. Closed-ended interview questions were treated as categorical variables. Thematic analysis was performed on qualitative data. Bivariate analysis tested associations between categorical variables.

RESULTS

Themes that emerged included: the decision to pursue UTx is a process, primary motivations for UTx are specific to the experience of gestation, and alternative options did not offer the same value as UTx. There was no association between disease etiology, clinical status, or perception of UTx risk with information needs or donor preference.

CONCLUSIONS

Our findings suggest that UTx is a unique treatment option that some women with AUFI find preferable to adoption and surrogacy and, as such, should be discussed as a parenthood option with women diagnosed with AUFI.

Coronavirus disease 2019: Utilizing an ethical framework for rationing absolutely scarce health-care resources in transplant allocation decisions

The novel coronavirus disease 2019 (COVID-19) is impacting transplant programs around the world, and, as the center of the pandemic shifts to the United States, we have to prepare to make decisions about which patients to transplant during times of constrained resources. In this paper, we discuss how to transition from the traditional justice versus utility consideration in organ allocation to a more nuanced allocation scheme based on ethical values that drive decisions in times of absolute scarcity. We recognize that many decisions are made based on the practical limitations that transplant programs face, especially at the extremes. As programs make the transition from a standard approach to a resource-constrained approach to transplantation, we utilize a framework for ethical decisions in settings of absolutely scarce resources to help guide programs in deciding which patients to transplant, which donors to accept, how to minimize risk, and how to ensure the best utilization of transplant team members.

Considering Uterus Transplantation for a Same-Sex Couple: A Case Study

A woman with congenital absence of a uterus applied for participation in a clinical trial for uterus transplantation. She was married to a woman who had the potential to carry a child without the need for aggressive medical intervention. Thus, the question arose regarding whether the infertile partner should be considered for uterus transplantation. In this article we discuss the ethical issues with uterus transplantation for a member of a same-sex couple, whose partner could carry a pregnancy. We review the medical criteria for uterus transplantation, discuss the additional options for parenthood in same-sex couples, examine how to determine if this meets the criteria of just distribution of uterus grafts, and ultimately argue that the value of gestation is at the level of the individual rather than the couple.

How Should We Decide Whether and When Some Care Is Better Than No Care?

This case of cleft lip and palate repair by a surgical mission team is common. Low-risk, single-procedure surgical interventions requiring minimal follow-up with substantial quality of life improvement are well suited for this type of mission. However, cleft repair can also be quite complex and require multiple surgeries and other care over time, postoperative surveillance, and speech therapy. These benefits and burdens prompt us to investigate, from clinical and ethical perspectives, whether and when some surgical care is better than none. We argue that, when performing surgical interventions in low- and middle-income countries, mission teams should consider a systems-based approach that emphasizes collaboration, context, and sustainability.

Alterations in muscle activation patterns during robotic-assisted walking

OBJECTIVE

The goal of this study was to compare the muscle activation patterns in various major leg muscles during treadmill ambulation with those exhibited during robotic-assisted walking.

BACKGROUND

Robotic devices are now being integrated into neurorehabilitation programs with promising results. The influence of these devices on altering naturally occurring muscle activation patterns utilized during walking have not been quantified.

METHODS

Muscle activity measured during 60 s of walking was broken up into individual stride cycles, averaged, and normalized. The stride cycle was then broken up into seven distinct phases and the integrated muscle activity during each phase was compared between treadmill and robotic-assisted walking using a multi-factor ANOVA.

RESULTS

Significant differences in the spatial and temporal muscle activation patterns were observed across various portions of the gait cycle between treadmill and robotic-assisted walking. Activity in the quadriceps and hamstrings was significantly higher during the swing phase of Lokomat walking than treadmill walking, while activity in the ankle flexor and extensor muscles was reduced throughout most of the gait cycle in the Lokomat.

CONCLUSIONS

Walking within a robotic orthosis that limits the degrees of freedom of leg and pelvis movement leads to changes in naturally occurring muscle activation patterns.

RELEVANCE

An understanding of how robotic-assisted walking alters muscle activation patterns is necessary clinically in order to establish baseline patterns against which subject's with neurological disorders can be compared. Furthermore, this information will guide further developments in robotic devices targeting gait training.

Cataracts in farmed Atlantic salmon (Salmo salar) in Ireland, Norway and Scotland from 1995 to 1997

From 1995 to 1997 cataracts were observed in Atlantic salmon (Salmo salar) in Ireland, Norway and Scotland at around the time of smoltification (when freshwater fish become adapted to the hypertonic seawater) in both fresh- and seawater fish. Over 38,000 fish were screened for the presence of cataracts. Posterior cortical cataracts were the earliest and most consistent change, followed by perinuclear, equatorial and anterior cortical cataracts. On histological examination vacuolation of the lens fibres was consistently present in the posterior cortex. The pattern of the outbreak suggested that a nutritional factor was involved although the variable incidence and severity of the condition indicated that a number of modifying factors may have been involved in the expression of the condition.

Preliminary findings of ophthalmological abnormalities in farmed halibut

Ocular abnormalities occurring in farmed halibut at the Sea Fish Industry Authority Marine Farming Unit, Ardtoe, Argyll were investigated clinically and post mortem. A significant number of fish were found to have posterior polar cystic changes either causing scleral ectasia or gross degenerative posterior segment abnormalities with chorioretinal atrophy. Other ocular abnormalities included cataract formation and intraocular inflammation. In a small number of fish gas bubble formation in the anterior chamber was observed during capture and examination. It is possible that the lesions seen in these fish are a form of gas bubble disease although super-saturation, the cause of gas bubble disease previously reported in farmed fish, does not occur in the tanks in which these fish are housed. While this paper provides no answers with regard to the aetiopathogenesis of the lesions, it is hoped that it will stimulate discussion, leading to resolution of these questions through a multidisciplinary approach to the problem.

Occurrence of cataracts in triploid Atlantic salmon (Salmo salar) on four farms in Scotland

In September 1991 cataracts occurred in two year-classes of triploid Atlantic salmon. The fish showed varying degrees of blindness, were lethargic and became emaciated owing to their inability to feed. The lesions in the lens were mainly in the anterior and posterior cortex and perinuclear areas, the capsule and embryonic nucleus remaining unaffected. Diploid fish of the same year-class did not have cataracts. The origin of the triploid fish, the method of triploidisation, their diet and disease status were investigated, but no predisposing factors could be found to account for the high incidence of cataracts.