Achieving ultra-low and -uniform residual magnetic fields in a very large magnetically shielded room for fundamental physics experiments.

High-precision searches for an electric dipole moment of the neutron (nEDM) require stable and uniform magnetic field environments. We present the recent achievements of degaussing and equilibrating the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute. We present the final degaussing configuration that will be used for n2EDM after numerous studies. The optimized procedure results in a residual magnetic field that has been reduced by a factor of two. The ultra-low field is achieved with the full magnetic-field-coil system, and a large vacuum vessel installed, both in the MSR. In the inner volume of ∼1.4m3, the field is now more uniform and below 300 pT. In addition, the procedure is faster and dissipates less heat into the magnetic environment, which in turn, reduces its thermal relaxation time from 12h down to 1.5h.

The very large n2EDM magnetically shielded room with an exceptional performance for fundamental physics measurements.

We present the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute, which features an interior cubic volume with each side of length 2.92 m, thus providing an accessible space of 25 m3. The MSR has 87 openings of diameter up to 220 mm for operating the experimental apparatus inside and an intermediate space between the layers for housing sensitive signal processing electronics. The characterization measurements show a remanent magnetic field in the central 1 m3 below 100 pT and a field below 600 pT in the entire inner volume, up to 4 cm to the walls. The quasi-static shielding factor at 0.01 Hz measured with a sinusoidal 2 µT peak-to-peak signal is about 100 000 in all three spatial directions and increases rapidly with frequency to reach 108 above 1 Hz.

A review of utilities and costs of treating upper extremity amputations with vascularized composite allotransplantation versus myoelectric prostheses in Canada.

Background: Hand vascularized composite allotransplantation (VCA) and myoelectric prostheses have proven their efficacy for treating hand amputation. Despite reported functional outcomes, the lack of consensus on VCA versus myoelectric prostheses brought us to report on their utilities and costs within the Canadian healthcare system. Methods: A review of utility outcomes and costs was performed for VCA and myoelectric prostheses and a comparison between unilateral versus bilateral amputations was made. Results: The simulation model demonstrated that significant savings could be achieved with both hand transplantation ($10.04 billion) and myoelectric prostheses ($12.17 billion) in all Canadian patients sustaining hand amputation with a 30-year life expectancy., Myoelectric prosthesis had lowest total cost compared to hand VCA by generating savings of $4,458,445,840 and $1,868,121,840 when compared to bilateral and unilateral upper limb amputations respectively. Conclusion: Treatment of unilateral amputations with myoelectric prostheses would cost significantly less to the society, whereas the gap in cost savings becomes less significant in bilateral amputees. From the socioeconomic standpoint of the Canadian healthcare system, this simulation model demonstrates that significant savings can be achieved with both treatments.

The design of the n2EDM experiment: nEDM Collaboration.

We present the design of a next-generation experiment, n2EDM, currently under construction at the ultracold neutron source at the Paul Scherrer Institute (PSI) with the aim of carrying out a high-precision search for an electric dipole moment of the neutron. The project builds on experience gained with the previous apparatus operated at PSI until 2017, and is expected to deliver an order of magnitude better sensitivity with provision for further substantial improvements. An overview is of the experimental method and setup is given, the sensitivity requirements for the apparatus are derived, and its technical design is described.

Data blinding for the nEDM experiment at PSI.

Psychological bias towards, or away from, prior measurements or theory predictions is an intrinsic threat to any data analysis. While various methods can be used to try to avoid such a bias, e.g. actively avoiding looking at the result, only data blinding is a traceable and trustworthy method that can circumvent the bias and convince a public audience that there is not even an accidental psychological bias. Data blinding is nowadays a standard practice in particle physics, but it is particularly difficult for experiments searching for the neutron electric dipole moment (nEDM), as several cross measurements, in particular of the magnetic field, create a self-consistent network into which it is hard to inject a false signal. We present an algorithm that modifies the data without influencing the experiment. Results of an automated analysis of the data are used to change the recorded spin state of a few neutrons within each measurement cycle. The flexible algorithm may be applied twice (or more) to the data, thus providing the option of sequentially applying various blinding offsets for separate analysis steps with independent teams. The subtle manner in which the data are modified allows one subsequently to adjust the algorithm and to produce a re-blinded data set without revealing the initial blinding offset. The method was designed for the 2015/2016 measurement campaign of the nEDM experiment at the Paul Scherrer Institute. However, it can be re-used with minor modification for the follow-up experiment n2EDM, and may be suitable for comparable projects elsewhere.

Thiel-embalmed porcine placenta: A valid and reusable microsurgical practice model.

BACKGROUND: Simulation models are increasingly important for skill acquisition during microsurgery training. Prosthetics, living and non-living biological models have been proposed in the literature in the optics of recreating real-life scenarios in a controlled environment. This study aims to validate and prove the reusability of a novel non-living biological model: the porcine placenta. METHODS: A prospective comparative study was carried out to assess face and content validities of the proposed model, as well as the reusability and quality of the Thiel-embalming method. Participants were asked answer a questionnaire for each anastomosis they performed on porcine placental vessels of ≤2mm (small) and 2-4mm (large). Scores were classified according to different subgroups, either small or large vessels and first or second sessions. Reliability analysis of the questionnaire was carried out using Cronbach's α, to ensure an α>0.7. Median scores for each question were analyzed using boxplots and compared amongst each subgroup using a non-parametric independent Mann-Whitney U test. RESULTS: With nine participants, the Cronbach's α for each category of question was 0.867, 0.778, 0.720 and 0.593. Statistical differences were found between responses of small and large vessels on 5/10 questions, where large vessels reported higher validity. No statistical differences were found between scores of the first and second sessions. CONCLUSION: By evaluating face and content validity, the Thiel-embalmed porcine placenta has proven its suitability as a microsurgery model, especially for vessels of larger caliber. Qualities that distinguish this model is its reliable reusability, its low cost-effectiveness, and its ethical acceptability.

Measurement of the Permanent Electric Dipole Moment of the Neutron.

We present the result of an experiment to measure the electric dipole moment (EDM) of the neutron at the Paul Scherrer Institute using Ramsey's method of separated oscillating magnetic fields with ultracold neutrons. Our measurement stands in the long history of EDM experiments probing physics violating time-reversal invariance. The salient features of this experiment were the use of a ^{199}Hg comagnetometer and an array of optically pumped cesium vapor magnetometers to cancel and correct for magnetic-field changes. The statistical analysis was performed on blinded datasets by two separate groups, while the estimation of systematic effects profited from an unprecedented knowledge of the magnetic field. The measured value of the neutron EDM is d_{n}=(0.0±1.1_{stat}±0.2_{sys})×10^{-26} e.cm.

French translation and cross-cultural adaptation of the Michigan Hand Outcomes Questionnaire and the Brief Michigan Hand Outcomes Questionnaire.

Patient-Reported Outcome Measures (PROMs) are important clinical devices for evaluating injuries and surgeries of the hand. However, some of the most widely used questionnaires, such as the MHQ and bMHQ, are currently unavailable in French, which prevents them from being used in the French Canadian province of Quebec as well as in other French-speaking nations. We therefore intend to develop valid and culturally adapted French translations of the afore-mentioned questionnaires. Two independent bilingual translators converted all English questionnaires to French. Two distinct translators then translated the French versions back to English in reverse-blinded fashion. Discrepancies between the original and second English versions were examined by a committee of four bilingual healthcare professionals before final French translations of all documents were produced. Thirty patients bilingual in French and English were then asked to complete the original and French versions of the MHQ and bMHQ. Their answers were compared in order to assess the accuracy of our translation. In light of these findings, revised French versions were produced. French versions of the MHQ and bMHQ questionnaires produced metrological qualities of validity and fidelity with an inter-class correlation superior to 0.90 and a kappa coefficient of 0.81 to 1. Clinical applicability revealed the distribution of scores according to disease process was reproducible between the English and French versions. PROM translation requires a rigorous process in order to achieve strong metrological qualities in both the original and translated versions. We produced French translations of the MHQ and bMHQ by abiding to the Beaton method of cross-cultural adaptation of self-reported measures.

Impact of the number of veins repaired in short-term digital replantation survival rate.

BACKGROUND: Venous congestion/insufficiency plays a major role in failure of finger replantation. Despite acceptable salvage rates with postoperative anticoagulation or leeching, operative technique remains the most important predictor of success. However, there are no indications in the literature on the benefit of anastomosing single versus multiple veins. METHODS: A retrospective review of finger amputations from 2011 to 2013 was conducted. The analyzed endpoint was the finger survival rate at discharge depending on the number of veins repaired: multiple veins (group 1), only one vein (group 2), or no veins (group 3). Proportions were compared using v2 tests/Fisher's exact tests; p-value <0.05 was considered significant. RESULTS: Seventy-two patients with complete digital amputation were operated including 101 fingers. Twenty-seven fingers (26.7%) failed before hospital discharge, with 78% of failures due to venous complications versus 22% with an arterial etiology. Group 2 had 15 replantation failures due to venous causes as opposed to only one from group 1, representing a 1.27-fold (95% confidence interval (CI): 0.99, 1.34) increased relative risk of failure (p = 0.032). Similarly, five fingers from group 3 suffered venous complications, resulting in a 1.49-fold (95% CI: 1.02, 1.73) increased likelihood of failure in comparison to group 1 (p = 0.008). No significant difference was observed between having only one vein repaired versus none (RR: 1.1792, 95% CI: 0.83, 2.10, p = 0.502). CONCLUSION: Efforts toward favoring two-vein repair lead to better survival of the replanted fingers. More cases need to be analyzed before formulating conclusions on specific levels of amputation with regard to venous anastomoses.

Observation of Gravitationally Induced Vertical Striation of Polarized Ultracold Neutrons by Spin-Echo Spectroscopy.

We describe a spin-echo method for ultracold neutrons (UCNs) confined in a precession chamber and exposed to a |B0|=1 µT magnetic field. We have demonstrated that the analysis of UCN spin-echo resonance signals in combination with knowledge of the ambient magnetic field provides an excellent method by which to reconstruct the energy spectrum of a confined ensemble of neutrons. The method takes advantage of the relative dephasing of spins arising from a gravitationally induced striation of stored UCNs of different energies, and also permits an improved determination of the vertical magnetic-field gradient with an exceptional accuracy of 1.1 pT/cm. This novel combination of a well-known nuclear resonance method and gravitationally induced vertical striation is unique in the realm of nuclear and particle physics and should prove to be invaluable for the assessment of systematic effects in precision experiments such as searches for an electric dipole moment of the neutron or the measurement of the neutron lifetime.

Replantation vs revision amputation in single digit zone II amputations.

The objective of this study was to compare the functional outcomes of zone II amputations treated with either replantation or revision amputation at our institution to better aid patients in their decision making process regarding these treatment options. We conducted a comparative retrospective study. All cases of single digit amputations received at our replantation center between 2007 and 2011 were screened for single digit zone II injuries. These patients were stratified based on the treatment received: replantation vs revision amputation. Patients were called and invited to participate in the research project. Those who accepted to enter the study were asked to complete the Quick-DASH, the Beck Depression Inventory-short form, and a custom made questionnaire. There were seventeen patients with single digit zone II replantation and fourteen patients with similar injuries who underwent revision amputation and agreed to take part in the study. Our data revealed that the duration of sick leave, occupation after injury, professional and social reintegration, discontinued activities, and self-confidence were not statistically different between the two groups. The average hospital stay and the follow-up period of replanted individuals were longer. The replantation group did not have higher levels of pain or cold intolerance, and the global functional and esthetic satisfaction levels were similar between the two groups. Also, Beck Depression Inventory and Quick-DASH scores were not statistically different. Yet, significantly more patients in the replantation group would opt to repeat the replantation than revised patients would opt for revision amputation. From a functional viewpoint, our study suggests that revision amputation is not superior to replantation in zone II single digit amputations. This is valuable information that should be given to patients when deciding on the treatment process and to insure a proper informed consent.

Osteocutaneous free flaps for mandibular reconstruction: systematic review of their frequency of use and a preliminary quality of life comparison.

OBJECTIVES: To determine whether the fibula free flap is the most frequently used osteocutaneous flap for mandible reconstruction, and whether it provides quality of life, depression and anxiety advantages. METHODS: A systematic review of the public Medline database was conducted. Thirteen patients who underwent mandibular reconstruction at our hospital centre completed questionnaires to evaluate quality of life, depression and anxiety outcomes. RESULTS: The most frequently used free flaps are those of the fibula (n = 982), radial forearm (n = 201), iliac crest (n = 113), subscapular system (n = 50) and rib-serratus (n = 7). In our patient population, there was a trend towards a better quality of life in those with a fibula free flap. However, patients in this group were significantly younger than patients with other flap types (p = 0.025). Patients with a subscapular system free flap were more depressed (p = 0.031); however, they had large through-and-through defects. CONCLUSION: The flap used most frequently in the literature is the fibula free flap. Comparative quality of life data are lacking, and homogeneous populations should be used to reach significant conclusions.

Building a multidisciplinary team for burn treatment - Lessons learned from the Montreal tendon transfer experience.

Multidisciplinary teams (MDTs) represent a recognized component of care in the treatment of complex conditions such as burns. However, most institutions do not provide adequate support for the formation of these teams. Furthermore, the majority of specialists lack the managerial skills required to create a team and have difficulties finding the proper tools. Our objective is to provide an insight for health care professionals, who wish to form a MDT for burn treatment, on the challenges that are likely to be faced, and to identify key elements that may facilitate the establishment of such a project. The setting for this was a plastic surgery department and rehabilitation center at a national reference center. A qualitative analysis was performed on all correspondences related to our tetraplegia project, from 2006 to 2008. To guide our thematic analysis, we used a form of systems theory known as the complexity theory. The qualitative analysis was performed using the NVivo software (Version 8.0 QSR International Melbourne, Australia). Lastly, the data was organized in chronologic order. Three main themes emerged from the results: knowledge acquisition, project organizational setup and project steps design. These themes represented respectively 24%, 50% and 26% of all correspondences. Project steps design and knowledge acquisition correspondences increased significantly after the introduction of the mentor team to our network. We conclude that an early association with a mentor team is beneficial for the establishment of a MDT.

Les équipes multidisciplinaires (EMD) représentent une composante des soins reconnue dans le traitement de conditions complexes telles que les brûlures. Cependant, la plupart des institutions ne fournissent pas de soutien adéquat pour la formation de ces équipes. En outre, la majorité des spécialistes ne possède pas les compétences de gestion nécessaires pour créer une équipe et éprouvent souvent des difficultés à trouver les outils appropriés. Notre objectif est de fournir aux professionnels de soins de santé, qui souhaitent former une équipe multidisciplinaire pour le traitement des brûlures, un aperçu sur les défis susceptibles d'être confronter et d'identifier les éléments clés qui faciliteront la mise en place d'un tel projet. Cette étude a eu lieu dans un département de chirurgie plastique et un centre de réadaptation affilié à un centre de référence national. Une analyse qualitative a été effectuée sur toutes les correspondances relatives à notre projet de tétraplégie, de 2006 à 2008. Pour guider notre analyse thématique, nous avons utilisé une forme de la théorie des systèmes connu comme la théorie de la complexité. L'analyse qualitative a été réalisée en utilisant le logiciel NVivo (version 8.0 QSR International, Melbourne, Australie). Enfin, les données ont été organisées en ordre chronologique. Trois thèmes principaux ont émergé à partir des résultats: l'acquisition de connaissances, la configuration et l'organisation du projet ainsi que la conception des étapes du projet. Ces thèmes représentaient respectivement 24 %, 50 % et 26 % de toutes les correspondances. Les correspondances en lien avec la conception du projet et l'acquisition des connaissances ont considérablement augmenté suite à l'introduction de l'équipe de mentors à notre réseau. Nous concluons qu'une association précoce avec une équipe de mentors est bénéfique à la mise en place d'une équipe multidisciplinaire.

[A surgical follow-up platform to reduce complications in free flap surgery]. / Une plateforme de suivi chirurgical pour réduire les complications en reconstruction par lambeau libre.

STUDY OBJECTIVE: In 2007, the WHO adopted surgical safety as the theme for the 2nd global patient safety challenge. Measurement of surgical services was identified as a surgical care area in need of major improvements. Aware of this recommendation, a preliminary study was conducted in our hospital and showed that the incidence of complete necrosis in free flap surgery was 10.0 %, a rate among the highest found in medical literature. In that context, an interactive surgical follow-up platform (PICS) was implemented to monitor outcomes in free flap surgery. The hypothesis was to reduce the short-term failure of microsurgical reconstructions. PATIENTS AND METHODS: In Summer 2010, the tool for capturing and analyzing data (PICS) was implemented. All patients who underwent free flap reconstruction were prospectively registered in the platform. The primary endpoints to evaluate the effectiveness of the tool are the rates of surgical re-exploration and complete necrosis of the flap. RESULTS: From May 2010 to December 2011, 129 cases of free flap reconstruction were recorded. The rate of total flap necrosis was 10.0 % before database introduction and declined to 3.1 % afterwards (P<0.05). Take-backs occurred in 27.0 % of free flap reconstructions at baseline and in 10.1 % after implementation (P<0.01). CONCLUSION: The implementation of PICS is associated with a significant improvement of postoperative short-term outcomes in free flap surgery. This tool is effective to evaluate care services and provides an increased surgical safety for patients. Surgical teams are encouraged to implement a data collection tool in order evaluate operative care on a routine basis.

[Interventional angioradiology as a solution for microsurgical flap failure]. / La radioangiologie interventionnelle comme solution de sauvetage en microchirurgie.

The microsurgical failure rate is almost constant for several decades. We present two case reports describing a novel method of free flap salvage using angioradiological techniques. Our first case shows the potential utility of in situ thrombolysis, our second case describes the first use of stents within a microsurgical anastomosis. In boths cases, the flap would have been lost immediately, because flap revisions failed. Thus, before abandoning on a flap, one could perform a simple angiography to evaluate further angioradiological salvage possibilities and hereby contribute to improve long term microsurgical failure rate.

Chimaeric subscapular system free flap for complex oro-facial defects.

BACKGROUND: Ablation of locally advanced head and neck cancers generally results in large composite oro-facial defects. Due to the often-large segment of mandible missing, as well as the need to provide skin coverage and oral lining, reconstructive options are limited. We present our experience in oncologic head and neck reconstruction using chimaeric subscapular system free flaps. METHODS: We performed a retrospective chart review of patients presenting important through-and-through oro-facial defects following ablation of T3, T4a or T4b tumours in two university centres between 2005 and 2011. All defects were reconstructed with a subscapular system free flap that was harvested in a dorsal decubitus position. RESULTS: Sixteen patients (15 M, 1 F; mean age=60 years) underwent mandibular reconstruction with latissimus dorsi flaps with one or two skin paddles and one bony component based on the angular branch of the thoracodorsal artery. Fifteen patients received adjuvant radiotherapy. We experienced no flap loss. Donor-site complications were minimal, albeit a limitation of shoulder range of motion was found in four patients. Eight patients presented postoperative complications requiring re-intervention. Fourteen patients were able to recommence oral nutrition and their diction returned to normal in all but one. The mean follow-up period was 25 months. Aesthetic results were satisfactory upon atrophy of the latissimus dorsi muscle. CONCLUSIONS: In cases of extensive oro-facial defects involving a large mandibular segment, reconstruction with subscapular system free-tissue transfer is a safe and reliable technique that offers satisfactory functional and aesthetic results.

Evaluation of factors influencing confidence and trust in the patient-physician relationship: a survey of patient in a hand clinic.

OBJECTIVES: The purpose of this study was to identify the skills found most important to gain patient's trust from a patient's perspective. METHODS: One hundred and twenty-two patients were surveyed prospectively using a questionnaire assessing professionalism, physical environment, verbal and non-verbal communication skills. Factors required to establish a trusting patient-surgeon relationship were ranked in order of importance before and after initial consultation with a surgeon in a hand surgery clinic model. RESULTS: No significant relationship was identified between gender, age, education or income, and answers provided by respondents. Technical ability, verbal communication skills and respect of patient's autonomy by the physician were found most important. CONCLUSION: The visit with the surgeon significantly affected the ranking of some of the skills deemed important. Patients view respect of autonomy and verbal communication skills as the most important attributes when developing trust and confidence in a surgeon, followed by technical proficiency.

Ulnar subluxation of the median nerve following carpal tunnel release: a case report.

Complications of carpal tunnel release, while infrequent, include incomplete release resulting in persistent symptoms or recurrence due to postoperative scarring, as well as iatrogenic damage to nerves and vessels. We present the case of a patient who underwent carpal tunnel release with resolution of symptoms in the immediate postoperative period. At one and a half years post release he started to experience numbness and tingling in a median nerve distribution triggered by repetitive ulnar to radial deviation of the wrist, with no symptoms at rest. Dynamic ultrasound showed a subluxation of the median nerve from one side of the palmaris longus tendon to the other. The patient's symptoms were triggered as the median nerve squeezed in between the palmaris longus and flexor digitorum superficialis tendons.

[Residency in plastic surgery: comparison between the French and the Canadian Royal College programs]. / L'apprentissage de la chirurgie plastique :comparaison de la formation française et duprogramme de résidence canadien du Collège royal.

BACKGROUND: Learning plastic surgery in Montreal is different from learning plastic surgery in a French university. In Canada, all residency programs are accredited by a national structure: the Royal College of Physicians and Surgeons. We tried to highlight the differences that exist between the French and a North American academic system. MATERIAL AND METHOD: With the different rules and law that governs academic education in both countries, we analyzed the following elements: the residency selection, the program of plastic surgery (content and organisation), the system of evaluation and the diplomas. RESULT: The training of a Canadian plastic surgeon is very controlled. The recommendations of the Royal College guarantee to the resident who enters a program to have the means to acquire a complete training in quantity and in quality. On the four studied items, none is completely similar between both countries. Each having advantages and inconveniences as, for example, the selection of residency by interview or by the classifying national exam. CONCLUSION: Actually, few French plastic surgery programs could satisfy the requirements of the Royal College on several points, however without failing the training of French plastic surgeons. Nevertheless, we could be inspired by several elements (rotation in private practice,grouping together several academic hospitals. . .) to improve our system of training.