Editorial Commentary: Evidence for Patch Augmentation of Rotator Cuff Repair Is Weak

Rotator cuff repair has a substantial failure rate despite various attempts to improve outcome and prevent a retear. Patch augmentation is an intuitively appealing approach to seek to reduce failure rate and improve outcomes for patients. Two main augmentation approaches are used: "on-lay" and "bridging." The literature is heterogeneous, and the best approach is uncertain. The evidence on patch augmentation for rotator cuff repair is both disparate and weak. Large randomized trials and registry data are required to move the field, ensure patient safety, and avoid wasting precious resources.

A roadmap for delivering a human musculoskeletal cell atlas

Advances in single-cell technologies have transformed the ability to identify the individual cell types present within tissues and organs. The musculoskeletal bionetwork, part of the wider Human Cell Atlas project, aims to create a detailed map of the healthy musculoskeletal system at a single-cell resolution throughout tissue development and across the human lifespan, with complementary generation of data from diseased tissues. Given the prevalence of musculoskeletal disorders, this detailed reference dataset will be critical to understanding normal musculoskeletal function in growth, homeostasis and ageing. The endeavour will also help to identify the cellular basis for disease and lay the foundations for novel therapeutic approaches to treating diseases of the joints, soft tissues and bone. Here, we present a Roadmap delineating the critical steps required to construct the first draft of a human musculoskeletal cell atlas. We describe the key challenges involved in mapping the extracellular matrix-rich, but cell-poor, tissues of the musculoskeletal system, outline early milestones that have been achieved and describe the vision and directions for a comprehensive musculoskeletal cell atlas. By embracing cutting-edge technologies, integrating diverse datasets and fostering international collaborations, this endeavour has the potential to drive transformative changes in musculoskeletal medicine.

Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study

INTRODUCTION

The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures.

METHODS

In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025.

FINDINGS

Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2-6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5-5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4-10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32-4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23-11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation.

INTERPRETATION

After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification.

FUNDING

UK Research and Innovation and National Institute for Health Research.

1048 In Vitro Evaluation of the Response of Human Tendon-Derived Stromal Cells to a Novel Electrospun Suture

Aim

Recurrent tears after surgical tendon repair remain common, with 40% of rotator cuff repairs failing within one year. Repair failures can be partly attributed to the use of sutures not designed for the tendon cellular niche. Synthetic electrospun materials can mechanically support the tendon while providing topographical cues that modulate the immune response to promote wound healing. Here, a novel electrospun suture made from twisted polydioxanone (PDO) polymer filaments is compared to PDS II, a PDO suture clinically utilised in tendon repair.

Method

We evaluated the ability of electrospun suture and PDS II to support the attachment and proliferation of human tendon-derived stromal cells using PrestoBlue cell viability assays and scanning electron microscopy. Suture surface chemistry was analysed using X-ray photoelectron spectroscopy (XPS). Bulk RNA-Seq interrogated the transcriptional response of primary tendon-derived stromal cells to sutures after 14 days.

Results

The electrospun suture showed increased initial cell attachment compared to PDS II. XPS revealed that both sutures had similar local surface chemistry, indicating that the tendon-like architecture of electrospun suture was responsible for the greater cell attachment. Furthermore, electrospun suture elicited a stronger transcriptional response compared with PDS II, with relative enrichment of pathways including mTorc1 signalling and depletion of epithelial-to-mesenchymal transition and extracellular matrix gene sets. Neither suture induced transcriptional upregulation of inflammatory pathways.

Conclusion

Twisted electrospun sutures show promise in improving outcomes in surgical tendon repair by allowing increased cell attachment while maintaining a tissue response indicative of cell proliferation and wound healing, without significant fibrosis.

Serious adverse event rates and reoperation after arthroscopic shoulder surgery: population based cohort study

OBJECTIVE

To provide clinicians and patients with accurate risk estimates of serious adverse events after common elective shoulder arthroscopic procedures, including reoperation within one year.

DESIGN

Population based cohort study.

SETTING

Hospital Episode Statistics for NHS England, including civil registration mortality data from the Office for National Statistics.

PARTICIPANTS

288 250 arthroscopic shoulder procedures performed in 261 248 patients aged ≥16 years between 1 April 2009 and 31 March 2017. Elective procedures were grouped into subacromial decompression, rotator cuff repair, acromioclavicular joint excision, glenohumeral stabilisation, and frozen shoulder release.

MAIN OUTCOME MEASURES

The primary outcomes were rates of serious adverse events (mortality, pulmonary embolism, pneumonia, myocardial infarction, acute kidney injury, stroke, and urinary tract infection) requiring inpatient care within 90 days post-surgery. Secondary outcomes were specific adverse event rates at 90 days, and reoperations (including for deep infection) within one year.

RESULTS

The overall rate of complications within 90 days after arthroscopic shoulder surgery (including reoperation) was low at 1.2% (95% confidence interval 1.2% to 1.3%), with one in 81 patients at risk, and varied according to type of procedure, from 0.6% (0.5% to 0.8%) for glenohumeral stabilisation to 1.7% (1.5% to 1.8%) for frozen shoulder release. After adjustment for age, comorbidities, and sex, no effect of procedure type was observed. Pneumonia was the most common adverse event (0.3%, 0.3% to 0.4%), with one in 303 patients at risk. Pulmonary embolic events were rare, at 0.1% (0.1% to 0.1%), with one in 1428 patients at risk. At one year, the overall rate for reoperation was 3.8% (3.8% to 3.9%), with one in 26 patients at risk, ranging from 2.7% (2.5% to 3.0%) for glenohumeral stabilisation to 5.7% (5.4% to 6.1%) for frozen shoulder release. The overall rate of further surgery for deep infection was low, at 0.1% (0.1% to 0.1%), with one in 1111 patients at risk, but was higher after rotator cuff repair (0.2%, 0.2% to 0.2%), with one in 526 patients at risk. Over the study period the number of arthroscopic shoulder procedures increased, except for subacromial decompression, which decreased.

CONCLUSIONS

The findings of this study suggest that risks of serious adverse events associated with common shoulder arthroscopy procedures are low. Nevertheless, serious complications do occur, and include the risk of reoperation in one in 26 patients within one year.

STUDY REGISTRATION

Clinical.

TRIALS

gov NCT03573765.

Early development of a polycaprolactone electrospun augment for anterior cruciate ligament reconstruction

Despite the clinical success of Anterior Cruciate Ligament reconstruction (ACLR) in some patients, unsatisfactory clinical outcomes secondary to graft failure are seen, indicating the need to develop new regeneration strategies. The use of degradable and bioactive textiles has the potential to improve the biological repair of soft tissue. Electrospun (ES) filaments are particularly promising as they have the ability to mimic the structure of natural tissues and influence endogenous cell behaviour. In this study, we produced continuous polycaprolactone (PCL) ES filaments using a previously described electrospinning collection method. These filaments were stretched, twisted, and assembled into woven structures. The morphological, tensile, and biological properties of the woven fabric were then assessed. Scanning electron microscopy (SEM) images highlighted the aligned and ACL-like microfibre structure found in the stretched filaments. The tensile properties indicated that the ES fabric reached suitable strengths for a use as an ACLR augmentation device. Human ACL-derived cell cultured on the fabric showed approximately a 3-fold increase in cell number over 2 weeks and this was equivalent to a collagen coated synthetic suture commonly used in ACLR. Cells generally adopted a more elongated cell morphology on the ES fabric compared to the control suture, aligning themselves in the direction of the microfibres. A NRU assay confirmed that the ES fabric was non-cytotoxic according to regulatory standards. Overall, this study supports the development of ES textiles as augmentation devices for ACLR.

Findings from the patch augmented rotator cuff surgery (PARCS) feasibility study

Background

A rotator cuff tear is a common disabling shoulder problem. Symptoms include pain, weakness, lack of mobility and sleep disturbance. Many patients require surgery to repair the tear; however, there is a high failure rate. There is a pressing need to improve the outcome of rotator cuff surgery. The use of patch augmentation to provide support to the healing process and improve patient outcomes holds new promise. Different materials (e.g. human/animal skin or intestine tissue, and completely synthetic materials) and processes (e.g. woven or a mesh) have been used to produce patches. However, clinical evidence on their use is limited. The patch augmented rotator cuff surgery (PARCS) feasibility study aimed to determine the design of a definitive randomised controlled trial (RCT) assessing the effectiveness and cost-effectiveness of a patch to augment surgical repair of the rotator cuff that is both acceptable to stakeholders and feasible.

Methods

A mixed methods feasibility study of conducing a subsequent RCT. The project involved six stages: a systematic review of clinical evidence; a survey of the British Elbow and Shoulder Society’s (BESS) surgical membership; a survey of surgeon trialists; focus groups and interviews with stakeholders; a two-round Delphi study administered via online questionnaires and a 2-day consensus meeting.

Results

The BESS surgeons’ survey identified a variety of patches in use (105 (21%) responses received). Twenty-four surgeons (77%) completed the trialist survey relating to trial design. Four focus groups were conducted involving 24 stakeholders. Twenty-nine (67% of invited) individuals took part in the Delphi. Differing views were held on a number of aspects including the appropriate patient population for trial participation. Agreement on the key research questions and the outline of two potential RCTs were achieved through the Delphi study and the consensus meeting.

Conclusions

Randomised comparisons of on-lay patch use for completed rotator cuff repairs, and bridging patch use for partial rotator cuff repairs were identified as areas for further research. The value of an observational study to assess safety concerns of patch use was also highlighted. The main limitation was that the findings were influenced by the participants, who might not necessarily reflect all stakeholders.

Rheumatoid pannus presenting as a large epidural mass in the subaxial cervical spine: A case report

Rheumatoid arthritis (RA) is a debilitating inflammatory condition characterised by joint damage that affects the cervical spine most commonly at the atlantoaxial joint resulting in neck pain and myelopathy. The pathogenesis of RA involves the formation of a hyperplastic synovial tissue, termed pannus, which invades the local bone and causes osseous erosion. Here, we describe a case of rapid onset quadriparesis due to spinal cord compression at C5-C6 secondary to vertebral subluxation and mass effect from a large inflammatory pannus in the subaxial spine. Surgical decompression and resection of the subaxial pannus were performed, and the patient regained strength in all extremities. Histopathologic evaluation of the resected tissue confirmed the diagnosis of pannus over other more common epidural masses. Pannus formation commonly occurs in the peri-odontoid region; however, its presentation as a large soft tissue mass in the subaxial spine is not described in the current literature. Therefore, pannus should be considered in the differential diagnosis of epidural masses in the spine of RA patients. We use this case to discuss the pathology and radiological findings relevant to rheumatoid pannus formation in the subaxial cervical spine, as well as emphasise the importance of treatment in the context to severe degenerative disease.

Patch augmentation surgery for rotator cuff repair: the PARCS mixed-methods feasibility study

BACKGROUND

A rotator cuff tear is a common, disabling shoulder problem. Symptoms may include pain, weakness, lack of shoulder mobility and sleep disturbance. Many patients require surgery to repair the tear; however, there is a high failure rate. There is a need to improve the outcome of rotator cuff surgery, and the use of patch augmentation (on-lay or bridging) to provide support to the healing process and improve patient outcomes holds promise. Patches have been made using different materials (e.g. human/animal skin or tissue and synthetic materials) and processes (e.g. woven or mesh).

OBJECTIVES

The aim of the Patch Augmented Rotator Cuff Surgery (PARCS) feasibility study was to determine the design of a definitive randomised controlled trial assessing the clinical effectiveness and cost-effectiveness of a patch to augment surgical repair of the rotator cuff that is both acceptable to stakeholders and feasible.

DESIGN

A mixed-methods feasibility study of a randomised controlled trial.

DATA SOURCES

MEDLINE, EMBASE and the Cochrane Library databases were searched between April 2006 and August 2018.

METHODS

The project involved six stages: a systematic review of clinical evidence, a survey of the British Elbow and Shoulder Society's surgical membership, a survey of surgeon triallists, focus groups and interviews with stakeholders, a two-round Delphi study administered via online questionnaires and a 2-day consensus meeting. The various stakeholders (including patients, surgeons and industry representatives) were involved in stages 2-6.

RESULTS

The systematic review comprised 52 studies; only 15 were comparative and, of these, 11 were observational (search conducted in August 2018). These studies were typically small (median number of participants 26, range 5-152 participants). There was some evidence to support the use of patches, although most comparative studies were at a serious risk of bias. Little to no published clinical evidence was available for a number of patches in clinical use. The membership survey of British Elbow and Shoulder surgeons [105 (21%) responses received] identified a variety of patches in use. Twenty-four surgeons (77%) completed the triallist survey relating to trial design. Four focus groups were conducted, involving 24 stakeholders. Differing views were held on a number of aspects of trial design, including the appropriate patient population (e.g. patient age) to participate. Agreement on the key research questions and the outline of two potential randomised controlled trials were achieved through the Delphi study [29 (67%)] and the consensus meeting that 22 participants attended.

LIMITATIONS

The main limitation was that the findings were influenced by the participants, who are not necessarily representative of the views of the relevant stakeholder groups.

CONCLUSION

The need for further clinical studies was clear, particularly given the range and number of different patches available.

FUTURE WORK

Randomised comparisons of on-lay patch use for completed rotator cuff repairs and bridging patch use for partial rotator cuff repairs were identified as areas for further research. The value of an observational study to assess safety concerns of patch use was also highlighted. These elements are included in the trial designs proposed in this study.

STUDY REGISTRATION

The systematic review is registered as PROSPERO CRD42017057908.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 13. See the NIHR Journals Library website for further project information.

Use of implantable meshes for augmented rotator cuff repair: a systematic review and meta-analysis

OBJECTIVE

To appraise studies reporting on clinical effectiveness and safety of surgical meshes used to augment rotator cuff repairs (RCRs).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE, Embase and Cochrane databases were searched between April 2006 and April 2020.

ELIGIBILITY CRITERIA

All studies evaluating adults (≥18 years) undergoing RCR were considered. There were no language restrictions.

DATA EXTRACTION AND SYNTHESIS

Screening, data extraction and quality appraisal were conducted by two independent reviewers. Meta-analysis was conducted using a random-effects models if ≥2 comparative studies reported the same outcome measure. Risk of bias assessment was undertaken for randomised (RoB2, Cochrane) and comparative studies (ROBINS-I, Cochrane).

RESULTS

We included 60 studies, consisting of 7 randomised controlled trials, 13 observational comparative studies and 40 observational case series. All comparative studies reported on shoulder-specific functional outcome scores, 18 on the radiographic occurrence of re-tear and 14 on pain score metrics. All studies contained some risk of bias.Compared with non-augmented repair, a small improvement in shoulder-specific function or pain scores was observed for synthetic patches with a mean improvement of 6.7 points on the University of California Los Angles (UCLA) shoulder score (95% CI 0.1 to 13.4) and 0.46 point reduction on the Visual Analogue Scale (95% CI -0.74 to -0.17), respectively. A reduced likelihood of radiologically observed re-tear was observed for synthetic (risk ratio (RR) 0.41, 95% CI 0.27 to 0.61) and allograft (RR 0.34, 95% CI 0.18 to 0.65) patches. A total of 49 studies reported on the occurrence of complications. Slightly higher crude complication rates were observed following patch-augmented repair (2.1%) than standard repair (1.6%).

CONCLUSIONS

While several studies suggest a decreased failure rate and small improvements in shoulder function and pain following augmented RCR, a paucity of rigorous clinical evaluation, for both effectiveness and safety, prevents firm recommendations.

PROSPERO REGISTRATION NUMBER

CRD42017057908.

P702Anti-thrombin nanoparticles for reduce vascular damage and promote functional recovery in acute ischemic kidney injury well after reperfusion

Introduction

We have shown previously that pretreatment of acute ischemic kidney injury (AKI) in mice prior to reperfusion with anti-thrombin perfluorocarbon nanoparticles (PFC NP) limits damage to endothelium and hastens functional recovery. However, whether such treatments are effective after AKI is established is not known. We hypothesized that thrombin would continue to exert deleterious clotting and molecular signaling effects in AKI well after reperfusion that would respond to sustained local inhibition with long acting anti-thrombin nanoparticles.

Methods

23 C57Bl6 mice underwent bilateral kidney ischemia for 17 min, followed by 2 hours reperfusion and i.v. injection of anti-thrombin PPACK (D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone)-conjugated PFC NP (∼ 13,000 PPACK per PFC NP), or plain PFC NP (control: no drug). At 24 hours BUN was measured, and mice were euthanized for kidney histological assessment (H&E), protein expression (western blot) and eicosanoid mediators of inflammation (LC-MS/MS: AB SCIEX 5500 QTRAP).

Results

BUN at 24 hours after AKI was 63.29±9.09 vs 110.96±6.21 (P<0.002), for treated versus untreated mice, respectively, a 43% improvement. Western blots (Figure) indicated 40% reduction of canonical NF-kB signaling pathway protein p65 (p<0.01) and 2.2 fold increases in Bcl-xL: Bax ratio (P<0.01). Vascular damage, as indicated by glomerular and mesangial hemorrhage (Figure), was reduced, as was tubular cell swelling and edema. Levels of inflammatory procoagulant eicosanoids (e.g., PGE1, TBX2, PGA2, 15-HETE, 5-HETE, etc.) generally were higher in renal medulla than in cortex, and were suppressed by PPACK PFC NP.

Discussion

Continued inhibition of thrombin in AKI with locally-acting PPACK PFC NP preserved vascular integrity, limited renal hemorrhage, mitigated inflammation and tubular cell death, and accelerated functional recovery even when administered 2 hours after reperfusion. Because these PPACK PFC NP do not prolong bleeding times or coagulation parameters beyond ∼30–60 min after injection, yet maintain prolonged local surveillance against activated thrombin, they represent a potentially useful therapeutic strategy for established AKI after an ischemic insult.

Acknowledgement/Funding

DK102691

Augmenting endogenous repair of soft tissues with nanofibre scaffolds

As our ability to engineer nanoscale materials has developed we can now influence endogenous cellular processes with increasing precision. Consequently, the use of biomaterials to induce and guide the repair and regeneration of tissues is a rapidly developing area. This review focuses on soft tissue engineering, it will discuss the types of biomaterial scaffolds available before exploring physical, chemical and biological modifications to synthetic scaffolds. We will consider how these properties, in combination, can provide a precise design process, with the potential to meet the requirements of the injured and diseased soft tissue niche. Finally, we frame our discussions within clinical trial design and the regulatory framework, the consideration of which is fundamental to the successful translation of new biomaterials.

Systematic review of the surgical management of rotator cuff repair with an augmentative patch: a feasibility study protocol

BACKGROUND

Shoulder pain is a common problem in the general population and is responsible for prolonged periods of disability, loss of productivity, absence from work and inability to carry out household activities. Rotator cuff problems account for up to 70% of shoulder pain problems and are the third most prevalent musculoskeletal disorder after those occurring in the lower back and neck. Rotator cuff surgery has high failure rates (25-50% within 12 months), and as a result, there is a pressing need to improve the outcome of rotator cuff surgery. Patch augmented surgery for rotator cuff repairs has recently been developed and is increasingly being used within the UK National Health Service. Patch augmented surgery could lead to a dramatic improvement in patient and surgical outcomes, but its clinical and cost effectiveness needs rigorous evaluation. The existing evidence on the use of patches may be at risk of bias as currently only a small number of single-centre comparative studies appear to have been carried out. Additionally, it is unclear for which patches a clinical study (comparative and non-comparative) has been conducted. This paper outlines the protocol for a systematic review intended to summarise the best available clinical evidence and will indicate what further research is required.

METHODS

Electronic databases (Medline, Embase and Cochrane) will be systematically searched between April 2006 and the present day for relevant publications using a specified search strategy, which can be adapted for the use in multiple electronic databases, and inclusion criteria. Screening of both titles and abstracts will be done by two independent reviewers with any discrepancies resolved by a third independent reviewer. Data extraction will include information regarding the type of participants, type of intervention and outcomes including but not limited to shoulder-specific function and pain scores, patch-related adverse events and type of study. The results will be summarised in a narrative review where qualitative analysis is not possible.

DISCUSSION

This review aims to collate the current evidence base regarding the use of patches to augment rotator cuff repair. The results of this review will help to develop, using consensus methods, the design of a definitive randomised trial assessing the clinical and cost-effectiveness of a patch to augment surgical repair of the rotator cuff that is both acceptable to stakeholders and is feasible.

SYSTEMATIC REVIEW REGISTRATION

CRD42017057908.

First Results from the DEAP-3600 Dark Matter Search with Argon at SNOLAB

This Letter reports the first results of a direct dark matter search with the DEAP-3600 single-phase liquid argon (LAr) detector. The experiment was performed 2 km underground at SNOLAB (Sudbury, Canada) utilizing a large target mass, with the LAr target contained in a spherical acrylic vessel of 3600 kg capacity. The LAr is viewed by an array of PMTs, which would register scintillation light produced by rare nuclear recoil signals induced by dark matter particle scattering. An analysis of 4.44 live days (fiducial exposure of 9.87 ton day) of data taken during the initial filling phase demonstrates the best electronic recoil rejection using pulse-shape discrimination in argon, with leakage <1.2×10^{-7} (90% C.L.) between 15 and 31  keV_{ee}. No candidate signal events are observed, which results in the leading limit on weakly interacting massive particle (WIMP)-nucleon spin-independent cross section on argon, <1.2×10^{-44}  cm^{2} for a 100  GeV/c^{2} WIMP mass (90% C.L.).

Validation of the updated ArthroS simulator: face and construct validity of a passive haptic virtual reality simulator with novel performance metrics

PURPOSE

To assess the construct and face validity of ArthroS, a passive haptic VR simulator. A secondary aim was to evaluate the novel performance metrics produced by this simulator.

METHODS

Two groups of 30 participants, each divided into novice, intermediate or expert based on arthroscopic experience, completed three separate tasks on either the knee or shoulder module of the simulator. Performance was recorded using 12 automatically generated performance metrics and video footage of the arthroscopic procedures. The videos were blindly assessed using a validated global rating scale (GRS). Participants completed a survey about the simulator's realism and training utility.

RESULTS

This new simulator demonstrated construct validity of its tasks when evaluated against a GRS (p ≤ 0.003 in all cases). Regarding it's automatically generated performance metrics, established outputs such as time taken (p ≤ 0.001) and instrument path length (p ≤ 0.007) also demonstrated good construct validity. However, two-thirds of the proposed 'novel metrics' the simulator reports could not distinguish participants based on arthroscopic experience. Face validity assessment rated the simulator as a realistic and useful tool for trainees, but the passive haptic feedback (a key feature of this simulator) is rated as less realistic.

CONCLUSION

The ArthroS simulator has good task construct validity based on established objective outputs, but some of the novel performance metrics could not distinguish between surgical experience. The passive haptic feedback of the simulator also needs improvement. If simulators could offer automated and validated performance feedback, this would facilitate improvements in the delivery of training by allowing trainees to practise and self-assess.

Discordant Observation of Brain Injury by MRI and Malignant Electroencephalography Patterns in Comatose Survivors of Cardiac Arrest following Therapeutic Hypothermia

BACKGROUND AND PURPOSE

Malignant electroencephalography patterns are considered predictive of poor outcome in comatose survivors of cardiac arrest. We hypothesized that malignant patterns on electroencephalography are associated with evidence of more severe brain injury on MR imaging.

MATERIALS AND METHODS

Retrospective review of clinical, imaging, and electroencephalography data of 33 adult comatose survivors of cardiac arrest following therapeutic hypothermia was performed. Outcomes measured included discharge destination and survival. Imaging studies were visually scored for severity of brain injury. Mean whole-brain apparent diffusion coefficient and percentage of severely injured brain (ADC < 700 × 10^-6 mm²/s) were calculated. Continuous electroencephalographic interpretation was characterized as malignant or nonmalignant. Nonparametric tests were performed to assess the relationship of patient outcome, MR imaging, and electroencephalography patterns.

RESULTS

Subjects with anatomic evidence of diffuse brain injury were less likely to have malignant electroencephalography patterns. Subjects with malignant electroencephalography patterns, invariably associated with bad outcomes, were observed to have whole-brain apparent diffusion coefficient measures similar to those in subjects with nonmalignant electroencephalography patterns and good outcome and different from those in subjects with nonmalignant electroencephalography patterns and bad outcomes. Regional hippocampal or basal ganglia injury was associated with a bad outcome regardless of electroencephalography findings.

CONCLUSIONS

We found discordant evidence of brain injury by MR imaging and electroencephalography, refuting our initial hypothesis. Malignant electroencephalography patterns were generally more frequent in subjects with less severe brain injury by MR imaging. These findings suggest a complementary role of MR imaging and electroencephalography and support the aggressive treatment of malignant electroencephalography patterns in this population.

Laparoscopic management of a delayed traumatic diaphragmatic rupture complicated by bowel strangulation

Traumatic rupture of the diaphragm (TDR) presents diagnostic difficulty, with basic radiological investigations discovering less than half of all cases. As a consequence, complications of diaphragmatic rupture may present long after the initial injury has occurred—the time delay obscuring diagnosis. Once discovered repair is necessary with previous reports advocating open repair. Here, we report a case of traumatic diaphragmatic rupture causing small bowel obstruction 20 years after initial injury. The patient, a young woman, underwent successful laparoscopic assisted diaphragmatic repair with small bowel resection. TDR is an unusual but important differential diagnosis of an acute abdomen. A high index of suspicion is required to avoid delayed diagnosis and increased mortality.

Identifying deafness in early childhood: requirements after the newborn hearing screen

BACKGROUND

Newborn hearing screening has been nationally implemented, but longitudinal cohort follow-up is required to inform Children's Hearing Services of the requirements for postneonatal care pathways.

METHODS

A 10-year cohort of 35 668 births enrolled into a Universal Neonatal Hearing Screen was followed up until the children had completed the first year of primary school.

RESULTS

There were 3.65/1000 children with a permanent hearing impairment of any degree embarking on their education. 1.51/1000 had a moderate or worse bilateral deafness but only 0.9/1000 with this degree of deafness had been identified by newborn screening. Postneonatal care pathways were required to identify those with congenital impairments missed by the screen (0.11/1000), those moving into the district (0.25/1000) and those with late onset deafness (0.25/1000). An additional postneonatal yield of 1.2/1000 had mild or unilateral impairments. When all degrees of impairment were considered 51% of the children with a permanent hearing impairment had required identification by postneonatal care pathways.

CONCLUSIONS

Despite the success of the newborn hearing screen, the provision of postneonatal pathways remains essential for identifying deafness in early childhood.

Plasma cell-free DNA in ovarian cancer: an independent prognostic biomarker

BACKGROUND

Cell-free DNA reflects both normal and tumor-derived DNA released into the circulation through cellular necrosis and apoptosis. The authors sought to determine the role of preoperative total plasma cell-free DNA levels in predicting clinical outcome in patients with ovarian cancer.

METHODS

After institutional review board consent, DNA was extracted from plasma of 164 women with invasive epithelial ovarian carcinoma (EOC), 49 with benign ovarian neoplasms, and 75 age-matched controls. The samples were randomly divided into training (n = 144) and validation (n = 144) sets. Quantification of cell-free DNA was performed using real-time polymerase chain reaction for beta-globin, and the number of genome equivalents (GE) per milliliter of plasma was determined. Cell-free DNA was correlated with clinicopathologic parameters.

RESULTS

The training and validation sets were similar in terms of demographic features. In the training set, EOC patients had a median preoperative cell-free DNA level of 10,113 GE/mL, compared with patients with benign ovarian neoplasms (median, 2365 GE/mL; P < .0001) and controls (median, 1912 GE/mL, P < .0001). Cell-free DNA >22,000 GE/mL was significantly associated with decreased patient survival (P < .001). After adjusting for other clinical variables, preoperative cell-free DNA >22,000 GE/mL was an independent predictor (P = .02) for disease-specific survival. Analysis of the validation set confirmed significantly higher cell-free DNA levels in EOC (median, 13,672 GE/mL) and that cell-free DNA >22,000 GE/mL was associated with a 2.83-fold increased risk of death from disease (P < .001).

CONCLUSIONS

Preoperative plasma total cell-free DNA levels are significantly elevated in patients with EOC. Elevated plasma cell-free DNA is an independent predictor for death from disease in ovarian cancer.

Increased perfusion and angiogenesis in a hindlimb ischemia model with plasmid FGF-2 delivered by noninvasive electroporation

Gene therapy approaches delivering fibroblast growth factor-2 (FGF-2) have shown promise as a potential treatment for increasing blood flow to ischemic limbs. Currently, effective noninvasive techniques to deliver plasmids encoding genes of therapeutic interest, such as FGF-2, are limited. We sought to determine if intradermal injection of plasmid DNA encoding FGF-2 (pFGF) followed by noninvasive cutaneous electroporation (pFGFE+) could increase blood flow and angiogenesis in a rat model of hindlimb ischemia. pFGFE+ or control treatments were administered on postoperative day 0. Compared to injection of pFGF alone (pFGFE-), delivery of pFGFE+ significantly increased FGF-2 expression for 10 days. Further, the increase in FGF-2 expression with pFGFE+ was sufficient to significantly increase ischemic limb blood flow, measured by laser Doppler perfusion imaging, beginning on postoperative day 3. Ischemic limb blood flow in the pFGFE+ treatment group remained significantly higher than all control groups through the end point of the study, postoperative day 14. Immunohistochemical staining of gastrocnemius cross sections determined there was a twofold increase in capillary density in the pFGFE+ treatment group. Our results suggest that pFGFE+ is a potential noninvasive, nonviral therapeutic approach to increase perfusion and angiogenesis for the treatment of limb ischemia.

Neurobehavioral functioning after cessation of manganese exposure: a follow-up after 14 years

BACKGROUND

Little is known on the long-term course of early manganese (Mn) neurotoxic effects. Mn alloy workers were examined in a follow-up study 14 years after exposure ceased at a Canadian facility.

METHODS

The same battery of neurofunctional tests used in the initial examination in 1990 was administered to 77 Mn-workers and 81 referents in 2004.

RESULTS

Manganese-workers had poorer scores compared to referents both in the initial and follow-up examinations for several motor tasks of the Luria Motor Scale. At follow-up, older Mn-workers (>45 years at cessation of exposure) had poorer scores than referents for tests of cognitive flexibility. Cumulated exposure was associated with poorer test scores for certain neuromotor and cognitive tests and on a mood scale. Differences on certain tests observed at initial examination were not present at follow-up.

CONCLUSIONS

Manganese exposure was associated with persistent deficits for certain neuromotor functions, cognitive flexibility, and adVerse mood states, while recovery occurred for other functions.

Reduction meatoplasty with a post-auricular island flap

The importance of an adequate meatoplasty is often emphasised in mastoid surgery. However, bigger is not always better, as an excessively widened external meatus can be cosmetically unacceptable, provide little extra benefit for cleaning, be an obstacle to the good fitting of hearing aids and expose the mastoid cavity to exaggerated caloric effect.

The problems created by an overly large meatus can occasionally be difficult to manage, prompting consideration of reduction of the meatus. We describe the use of a pedicled, post-auricular skin flap to achieve reduction of an excessively large meatus.

Field and model investigations of external gamma dose rates along the Cumbrian coast, NW England

A survey of the contribution to external dose from gamma rays originating from intertidal sediments in the vicinity of the British Nuclear Group Sellafield site showed that the major anthropogenic contributions were due to (137)Cs and (60)Co. At some sites, traces of other anthropogenic radionuclides were detected, namely (106)Ru, (125)Sb, and (154)Eu. The proportions of fine grained material (<63 microm) were used to improve model predictions of dose contribution due to external exposure to gamma rays, using the CUMBRIA77/DOSE77 model. Model dose predictions were compared to those directly measured in the field. Using the new proportions of fine grained material (1-17.5%) in conjunction with field gamma-ray spectra, model predictions were improved considerably for most sites. Exceptions were at Drigg Barn Scar and Whitehaven Coal Sands sites, which had their own unique characteristics. The highest (60)Co activity concentrations in this study were detected at Drigg Barn Scar. These relatively high activity concentrations of (60)Co were due to the presence of (60)Co in mussels and barnacles, hence upsetting the fine sediment relationships used in previous dose calculations. Whitehaven Coal Sands was unusual in that it contained higher levels of radionuclides than would be expected in sandy sediment. The mineralogy of these sediments was the controlling factor on (137)Cs binding, rather than the proportion of fine grained material. By adjusting the effective fine grained sediment proportions for calculations involving (60)Co and (137)Cs at Drigg Barn Scar and Whitehaven Coal Sands respectively, the CUMBRIA77/DOSE77 model predictions could be improved upon significantly for these sites. This work highlights the influence of particle size and sediment composition on external dose rate calculations, as well as the potential for external dose contributions from biota.

Malignancies of the external auditory canal and temporal bone: a review

BACKGROUND

Malignancies of the external auditory canal and temporal bone are uncommon. A retrospective review was conducted of a large series treated at the Prince of Wales hospital between 1974 and 1995.

METHODS

Retrospective review of 59 cases of ear canal and temporal bone malignancies. These were analysed according to histopathology, disease extent, surgery, margin status and survival. A TNM-type staging system was applied to 51 cases and Kaplan-Meier survival analysis applied to this group.

RESULTS

The 5-year cancer-specific survival (CSS) for the series was 54%. For stages 1, 2, 3 and 4 disease, the CSS were 90, 45, 40 and 19%, respectively. Survival was significantly higher where clear surgical margins were achieved (80 vs 35%).

CONCLUSIONS

Carcinoma of the external ear canal is rare and, in Australia, is often related to recurrence of periauricular cutaneous malignancy. Surgical extirpation with clear margins provides the best survival.

A model for providing prenatal health care to indigenous women living in remote areas

OBJECTIVE

To describe a model for providing health care services for indigenous women of childbearing age who do not have ready access to health care.

STUDY DESIGN

Program description and prospective annual survey medical records.

RESULTS

Measures of the success of this model of prenatal care include prenatal care initiated in the first trimester of pregnancy, low preterm birth, and low out of hospital birth. In 1985, the first year statistics were maintained, 31 percent of women entered prenatal care in their first trimester, 58 percent in their second trimester and 11 percent in their third trimester. In 1999, ninety-one percent of women initiated prenatal care in their first trimester, 9 percent in their second trimester and none waited until their third trimester to initiate care. This compares favorably with Indian Health Service data indicating that in Alaska 77.4 percent of women with live births entered care in their first trimester of pregnancy.

CONCLUSION

The Rural Maternal Child Health program at Alaska Native Medical Center has been successfully providing services to indigenous women and their families in 30 remote Alaska Native Villages.

[Association between work exposure to neurotoxic substances with workers' relationships with their social network]

BACKGROUND

This study explored the impact on family life and social relations that may result from symptoms associated with exposure to neurotoxic substances in the workplace. We assessed the associations between exposure to neurotoxic substances in the workplace, workers'mental health, and workers'relationships with their social network.

METHODS

A sample of 53 workers and their spouse completed a series of questionnaires, an interview on work history, and a structured interview assessing their personal relationships. Exposure to neurotoxic substances in the workplace were assessed by an interview, using a semiquantitative classification system. Mental health was measured with the Profile of Mood States (POMS), and marital satisfaction with the Marital Adjustment Test (MAT). The social network's characteristics were assessed with the Northern California Community Study Interview Schedule (NCCS). The associations between exposure and social networks were assessed with regression analyses.

RESULTS

There were no associations between exposure and marital satisfaction. However, we found a negative association between workers'exposure and degrees of overlap between husbands' and wives' social networks (Pearson's correlation r=-0.27; p<0.05) and a positive association between exposure and workers' dependency on their support network (r=0.46; p<0.01).

CONCLUSION

The results are discussed in terms of variables potentially linking exposure to social relationships as well as in terms of couples' vulnerability to marital distress among exposed workers.

Cumulative exposure to styrene and visual functions

BACKGROUND

Results from a 1990-1992 longitudinal study of several reinforced plastics plants showed that for those workers whose styrene exposure had decreased, color vision (CV) improved; while near visual contrast sensitivity (CS) was poorer.

METHODS

In 1999, we retested these visual functions in 18 workers with good visual acuity. A cumulative exposure index (CEI), corrected for respirator use, was calculated for each worker.

RESULTS

Intra-individual comparison of mandelic acid (MA) showed a significant decrease over time (Friedman; P = 0.015), but current values were not related to CEI. For CV, no significant difference was observed between 1992 and 1999; present results were not related to MA or CEI. The CS profile decreased over time, with significant differences at 3 cpd (Friedman; P < 0.05). CS did not vary with MA levels, but was significantly depressed at the intermediate frequencies among those in the upper CEIH category (Kruskal-Wallis; P < 0.05).

CONCLUSIONS

These findings suggest that CS loss increases with long-term cumulative exposure, reflecting chronic damage to the neuro-optic pathways.