[Virtual training of practical competences in sonography]. / Sonographie als Gegenstand virtuellen Wissenstransfers zum praktischen Kompetenzerwerb.

OBJECTIVE: During the COVID-19 pandemic, a particular challenge in the transition to digital teaching was to teach practical skills such as sonography of the head and neck online. The aim of this study was to validate the digital sonography course for medical students established at the Freiburg University Hospital ENT Department. METHODS: Participants were 178 students of human medicine. The study group simulated the sonography examination at home with a dummy transducer using the Peyton method under the guidance of a tutor via video seminar. In a subsequent learning success check, the results of the students in the online course were compared with those of the control group, who learned sonography in the classroom. RESULTS: Students of the online course achieved comparable results to the classroom group. CONCLUSION: This study shows that practical skills which require extensive equipment such as a sonography machine can be taught to a certain extent digitally or at least in a hybrid form.

The effect of fatigue on climbing fluidity and hand movements.

In rock climbing, climbers use their arms to regulate their posture on the wall, which can lead to localised muscle fatigue. Evidence shows fatigue is the primary cause of falls, but little is known about how fatigue specifically affects climbing rhythm and hand movements. The present study examined climbing fluidity and hand movements on an indoor climbing wall before and after a specific fatiguing protocol. Seventeen climbers completed three repetitions of a challenging climbing route (21 on Ewbank scale) with different levels of localised arm fatigue. Climbers' movements were tracked using 3D motion capture, and their hand actions assessed using notational analysis. Seventy markers were used to create 15 rigid body segments and the participants' centre of mass. The global entropy index was calculated on the path of the participants' centre of mass. Climbers fell more often when fatigued, but there were no significant differences in hip jerk or global entropy index when fatigued. No significant differences were found between the number of exploratory or performatory hand movements with different amounts of fatigue. The results suggest that localised arm fatigue affects a climber's ability to prevent themselves from falling, but it does not specifically affect their fluidity.

Short-term preoperative drainage is associated with improved postoperative outcomes compared to that of long-term biliary drainage in pancreatic surgery.

PURPOSE: The treatment of choice for patients presenting with obstructive cholestasis due to periampullary carcinoma is oncologic resection without preoperative biliary drainage (PBD). However, resection without PBD becomes virtually impossible in patients with obstructive cholangitis or severely impaired liver cell function. The appropriate duration of drainage by PBD has not yet been defined for these patients. METHODS: A retrospective analysis was conducted on 170 patients scheduled for pancreatic resection following biliary drainage between January 2012 and June 2018 at the University Hospital Dresden in Germany. All patients were deemed eligible for inclusion, regardless of the underlying disease entity. The primary endpoint analysis was defined as the overall morbidity (according to the Clavien-Dindo classification). Secondary endpoints were the in-hospital mortality and malignancy adjusted overall and recurrence-free survival rates. RESULTS: A total of 170 patients were included, of which 45 (26.5%) and 125 (73.5%) were assigned to the short-term (< 4 weeks) and long-term (≥ 4 weeks) preoperative drainage groups, respectively. Surgical complications (Clavien-Dindo classification > 2) occurred in 80 (47.1%) patients, with significantly fewer complications observed in the short-term drainage group (31.1% vs. 52%; p = 0.02). We found that long-term preoperative drainage (unadjusted OR, 3.386; 95% CI, 1.507-7.606; p < 0.01) and periampullary carcinoma (unadjusted OR, 5.519; 95% CI, 1.722-17.685; p-value < 0.01) were independent risk factors for postoperative morbidity, based on the results of a multivariate regression model. The adjusted overall and recurrence-free survival did not differ between the groups (p = 0.12). CONCLUSION: PBD in patients scheduled for pancreatic surgery is associated with substantial perioperative morbidity. Our results indicate that patients who have undergone PBD should be operated on within 4 weeks after drainage.

Implementation of written structured feedback into a surgical OSCE.

BACKGROUND: Feedback is an essential element of learning. Despite this, students complain about receiving too little feedback in medical examinations, e.g., in an objective structured clinical examination (OSCE). This study aims to implement a written structured feedback tool for use in OSCEs and to analyse the attitudes of students and examiners towards this kind of feedback. METHODS: The participants were OSCE examiners and third-year medical students. This prospective study was conducted using a multistage design. In the first step, an unstructured interrogation of the examiners formed the basis for developing a feedback tool, which was evaluated and then adopted in the next steps. RESULTS: In total, 351 students and 51 examiners participated in this study. A baseline was created for each category of OSCE station and was supplemented with station-specific items. Each of these items was rated on a three-point scale. In addition to the preformulated answer options, each domain had space for individual comments. A total of 87.5% of the students and 91.6% of the examiners agreed or rather agreed that written feedback should continue to be used in upcoming OSCEs. CONCLUSION: The implementation of structured, written feedback in a curricular, summative examination is possible, and examiners and students would like the feedback to be constant.

Functional outcomes after laparoscopic versus robotic-assisted rectal resection: a systematic review and meta-analysis.

Surgical resection is crucial for curative treatment of rectal cancer. Through multidisciplinary treatment, including radiochemotherapy and total mesorectal excision, survival has improved substantially. Consequently, more patients have to deal with side effects of treatment. The most recently introduced surgical technique is robotic-assisted surgery (RAS) which seems equally effective in terms of oncological control compared to laparoscopy. However, RAS enables further advantages which maximize the precision of surgery, thus providing better functional outcomes such as sexual function or contience without compromising oncological results. This review was done according to the PRISMA and AMSTAR-II guidelines and registered with PROSPERO (CRD42018104519). The search was planned with PICO criteria and conducted on Medline, Web of Science and CENTRAL. All screening steps were performed by two independent reviewers. Inclusion criteria were original, comparative studies for laparoscopy vs. RAS for rectal cancer and reporting of functional outcomes. Quality was assessed with the Newcastle-Ottawa scale. The search retrieved 9703 hits, of which 51 studies with 24,319 patients were included. There was a lower rate of urinary retention (non-RCTs: Odds ratio (OR) [95% Confidence Interval (CI)] 0.65 [0.46, 0.92]; RCTs: OR[CI] 1.29[0.08, 21.47]), ileus (non-RCTs: OR[CI] 0.86[0.75, 0.98]; RCTs: OR[CI] 0.80[0.33, 1.93]), less urinary symptoms (non-RCTs mean difference (MD) [CI] - 0.60 [- 1.17, - 0.03]; RCTs: - 1.37 [- 4.18, 1.44]), and higher quality of life for RAS (only non-RCTs: MD[CI]: 2.99 [2.02, 3.95]). No significant differences were found for sexual function (non-RCTs: standardized MD[CI]: 0.46[- 0.13, 1.04]; RCTs: SMD[CI]: 0.09[- 0.14, 0.31]). The current meta-analysis suggests potential benefits for RAS over laparoscopy in terms of functional outcomes after rectal cancer resection. The current evidence is limited due to non-randomized controlled trials and reporting of functional outcomes as secondary endpoints.

Revision of 116 orthognathic surgery patients operated on with the high-oblique sagittal osteotomy (HOSO): a retrospective case series (PROCESS-compliant article).

BACKGROUND: The high-oblique sagittal osteotomy (HOSO) is an alternative to a bilateral sagittal split osteotomy (BSSO). Due to its novelty, there are no long-term studies which have focused on describing the incidence and type of complications encountered in the post-operative follow-up. The aim of this retrospective study is to analyze patients operated on with this surgical technique and the post-operative complications encountered. PATIENT AND METHODS: The electronic medical records of all patients treated with orthognathic surgery at the Department of Oral, Maxillofacial and Facial Plastic Surgery, University Hospital Frankfurt, Goethe University, Frankfurt, Germany, between the years 2009 and 2016 were retrospectively reviewed. RESULTS: A total of 116 patients fulfilled the inclusion criteria. The cases operated on with the standard osteosynthesis (X, Y, and straight) showed a complication rate of 36.37% (n = 4/11). The cases operated on with the HOSO-dedicated plates (HOSO-DP) showed, in total, a complication rate of 6.67% (n = 7/105). The most common post-operative complication resulting from both fixation methods was a reduction in mouth opening and TMJ pain for 4.3%. During the first years of performing the surgery (2009-211), a variety of standard plates had material failure causing non-union or pseudarthrosis. No cases of material failure were observed in the cases operated on with the HOSO-DP. The statistical results showed a highly significant dependence of a reduction in OP-time over the years, when the HOSO was performed without additional procedures (R2 > 0.83, P < 0.0015). CONCLUSION: The rate of complications in the HOSO were shown to be comparable to the rate of complications from the BSSO reported in the literature. Moreover, the use of the ramus dedicated plate appears to provide enough stability to the bone segments, making the surgery safer. CLINICAL RELEVANCE: The HOSO needs to be considered by surgeons as an alternative to BSSO. Once the use of the HOSO-DP was established, the rate of complications and the operation time reduced considerably.

Does water temperature influence the performance of key survival skills?

Aquatic survival skills may be compromised in cold water thereby increasing the likelihood of drowning. This study compared physiological, psychological, and behavioral responses of humans treading water and swimming in cold and temperate water. Thirty-eight participants were classified as inexperienced (n = 9), recreational (n = 15), or skilled (n = 10) swimmers. They performed 3 tasks: treading water (120 seconds), swim at "comfortable" pace, and swim at "fast" pace in 2 water conditions (28°C vs 10°C). Heart rate, oxygen uptake, psychometric variables, spatio-temporal (swim speed, stroke rate, and stroke length), and coordination type were examined as a function of expertise. Tasks performed in cold water-generated higher cardiorespiratory responses (HR = 145 ± 16 vs 127 ± 21 bpm) and were perceived about 2 points more strenuous on the Borg scale on average (RPE = 14.9 ± 2.8 vs 13.0 ± 2.0). The voluntary durations of both treading water (60 ± 32 vs 91 ± 33 seconds) and swimming at a comfortable pace (66 ± 22 vs 103 ± 34 seconds) were significantly reduced in cold water. However, no systematic changes in movement pattern type could be determined in either the treading water task or the swimming tasks. Water temperature influences the physical demands of these aquatic skills but not necessarily the behavior. Training treading water and swimming skills in temperate water seems to transfer to cold water, but we recommend training these skills in a range of water conditions to help adapt to the initial "cold-shock" response.

Behavioural variability and motor performance: Effect of practice specialization in front crawl swimming.

The aim was to examine behavioural variability within and between individuals, especially in a swimming task, to explore how swimmers with various specialty (competitive short distance swimming vs. triathlon) adapt to repetitive events of sub-maximal intensity, controlled in speed but of various distances. Five swimmers and five triathletes randomly performed three variants (with steps of 200, 300 and 400m distances) of a front crawl incremental step test until exhaustion. Multi-camera system was used to collect and analyse eight kinematical and swimming efficiency parameters. Analysis of variance showed significant differences between swimmers and triathletes, with significant individual effect. Cluster analysis put these parameters together to investigate whether each individual used the same pattern(s) and one or several patterns to achieve the task goal. Results exhibited ten patterns for the whole population, with only two behavioural patterns shared between swimmers and triathletes. Swimmers tended to use higher hand velocity and index of coordination than triathletes. Mono-stability occurred in swimmers whatever the task constraint showing high stability, while triathletes revealed bi-stability because they switched to another pattern at mid-distance of the task. Finally, our analysis helped to explain and understand effect of specialty and more broadly individual adaptation to task constraint.

Inter-limb coordination and energy cost in swimming.

OBJECTIVES: This study investigated the relationship between inter-arm coordination and the energy cost of locomotion in front crawl and breaststroke and explored swimmers' flexibility in adapting their motor organization away from their preferred movement pattern. DESIGN: Nine front-crawlers performed three 300-m in front crawl and 8 breaststrokers performed three 200-m in breaststroke at constant submaximal intensity and with 5-min rests. Each trial was performed randomly in a different coordination pattern: freely chosen, 'maximal glide' and 'minimal glide'. Two underwater cameras videotaped frontal and side views to analyze speed, stroke rate, stroke length and inter-limb coordination. METHODS: In front crawl, inter-arm coordination was quantified by the index of coordination (IdC) and the leg beat kicks were counted. In breaststroke, four time gaps quantified the arm to leg coordination (i.e., time between leg and arm propulsions; time between beginning, 90° flexion and end of arm and leg recoveries). The energy cost of locomotion was calculated from gas exchanges and blood lactate concentration. RESULTS: In both front crawl and breaststroke, the freely chosen coordination corresponded to glide pattern and showed the lowest energy cost (12.8 and 17.1Jkg(-1)m(-1), respectively). Both front-crawlers and breaststrokers were able to reach 'maximal glide' condition (respectively, +35% and +28%) but not 'minimal glide' condition for front crawl. CONCLUSIONS: The freely chosen pattern appeared more economic because more trained. When coordination was constrained, the swimmers had higher coordination flexibility in breaststroke than in front crawl, suggesting that breaststroke coordination was easier to regulate by changing glide time.

Skill transfer, affordances and dexterity in different climbing environments.

This study explored how skills in one region of a perceptual-motor landscape of performance, created in part by previous experience in rock climbing, can shape those that emerge in another region (ice climbing). Ten novices in rock climbing and five intermediate rock climbers were observed climbing an icefall. Locations of right and left ice tools and crampons were videotaped from a frontal camera. Inter-individual variability of upper and lower limb couplings and types of action regarding icefall properties were assessed by cluster hierarchical analysis, distinguishing three clusters. Pelvis vertical displacement, duration and number of pelvis pauses were also analyzed. Experienced rock climbers were grouped in the same cluster and showed the highest range and variability of limb angular locations and coordination patterns, the highest vertical displacement and the shortest pelvis plateaux durations. Non-fluent climbers (clusters 2 and 3) showed low range and variability of limb angular locations and coordination patterns. In particular, climbers of cluster 3 exhibited the lowest vertical displacement, the longest plateaux durations and the greatest ratio between tool swinging and definitive anchorage. Our results exemplified the positive influence of skills in rock climbing on ice climbing performance, facilitated by the detection of affordances from environmental properties.

Effect of increasing energy cost on arm coordination in elite sprint swimmers.

The purpose of this study was to analyze the changes in stroke parameters, motor organization and swimming efficiency with increasing energy cost in aquatic locomotion. Seven elite sprint swimmers performed a 6×300-m incremental swimming test. Stroke parameters (speed, stroke rate and stroke length), motor organization (arm stroke phases and arm coordination index), swimming efficiency (swimming speed squared and hand speed squared) and stroke index were calculated from aerial and underwater side-view cameras. The energy cost of locomotion was assessed by measuring oxygen consumption and blood lactate. Results showed that the increase in energy cost of locomotion was correlated to an increase in the index of coordination and stroke rate, and a decrease in stroke length (p<.05). Furthermore, indicators of swimming efficiency and stroke index did not change significantly with the speed increments (p<.05), indicating that swimmers did not decrease their efficiency despite the increase in energy cost. In parallel, an increase in the index of coordination IdC and stroke rate were observed, along with a decrease in stroke length, stroke index and hand speed squared with each increment, revealing an adaptation to the fatigue within the 300m.

Inter-individual variability in the upper-lower limb breaststroke coordination.

The aim of the present study was to examine inter-individual variability in upper-lower limb breaststroke coordination. First, inter-individual variability was compared between recreational and comparative swimmers. Second, as recreational swimmers revealed more variable inter-limb coordination than competitive swimmers, inter-individual variability was assessed among recreational swimmers to identify coordination profiles. The elbow-knee continuous relative phase (CRP) was used to analyze upper-lower limbs coupling during a breaststroke cycle. Twenty-four recreational and twenty-four competitive swimmers swam 25 m at 80% of their maximal speed. Underwater and aerial side views were mixed and genlocked. Angular position, velocity and CRP were calculated for the knee and elbow joints by digitizing body markers from the side view. The kinematics of three cycles were filtered, averaged and normalized in terms of percentage of total cycle duration. The topography of the mean CRP curve of the recreational swimmers resembled a 'W-shape', whereas an 'inverse U-shape' was seen in the competitive swimmers. However, higher inter-individual variability was observed among the recreational swimmers than among the competitive swimmers (38.1° vs. 19.4°; p<.05), suggesting that several profiles of inter-limb coordination may exist in recreational swimmers. Coordination profiling showed that three clusters could classify the recreational swimmers.

Coordination profiles of the expert field hockey drive according to field roles.

The aim of this study was to determine coordination profiles for the field hockey drive. Nine elite female players performed five drives each. They were asked to primarily maximize ball placement accuracy, and secondly to drive with high velocity. An optical motion capture system recorded the displacement of six markers on the joints of the players' arms as they performed the drives, and a radar gun measured the ball velocity after impact. Spatial, temporal, and velocity variables were then established. Discrete relative phases were also established at ball impact to examine medio-lateral and proximo-distal upper-arms coordination. The high standard deviation values in joint kinematics were indicative of inter-individual variability, i.e. several drive solutions. Cluster analysis was thus used and two profiles among the players were identified. For the two profiles, the global coordination pattern of movement (upper-arm coordination) was in-phase for the right arm, and out-of-phase for the left lead arm, suggesting a segmental sequencing. However, differences were noted on local kinematic parameters which led to the following categorization: the 'strong group' for defenders and the 'temporal-effectiveness group' for midfielders and forwards. The results support the value of individual analysis to better interpret and contrast the distinct roles of expert players.

Hip velocity and arm coordination in front crawl swimming.

The hip intracyclic velocity variability and the index of coordination in front crawl swimming were examined in relation to performance level. 22 swimmers were assigned to either an elite or a recreational swimming group and performed 4 swim trials at different paces relative to their individual maximum velocity. A velocity meter system was set to determine intracyclic velocity variability and video analysis allowed the determination of the index of coordination. Mean intracyclic velocity variability was lower in the elite swimmers than the recreational swimmers (14.39 ± 1.97 vs. 17.80 ± 4.23%, p<0.05), and remained stable with swim pace (i. e., the relative velocity) for the elite group, whereas it increased for the recreational group (p<0.05). The elite swimmers were characterized by a lower mean index of coordination than the recreational swimmers (-9.6 ± 7.1 vs. -6.9 ± 5.0%, p<0.05), but it increased with swim velocity in the elite group and showed only a tendency in the recreational group (p=0.07). These findings suggest that low intracyclic velocity variability and its stability over a range of swimming paces, which result from optimized inter-arm coordination, are characteristic of skilled performance. Thus, the examination of intracyclic velocity variability and index of coordination variability with different swim paces could provide new insight into skilled performance in swimming.

Comparison of grab start between elite and trained swimmers.

This study analysed motor control during front crawl swimming starts by elite and trained swimmers, based on comparisons of: 1) kinematic and kinetic parameters of the start and 2) variability of these parameters across 3 trials per swimmer. Given that the start time to the 15-m mark is greatly influenced by the swimming phase, the study also compared the stroking and coordinative parameters from water entry to 25-m in the 2 skill groups. The swimmers performed 3 x 25-m at the 50-m race-pace and used their preferential start technique (grab start). The elite swimmers showed better start organization as reflected by higher impulse values in the direction of intended displacement despite similar block phase durations. They then spent more time in the water entry, gliding and leg kicking phases, with shorter swimming phase duration and 15-m start time than the trained swimmers (p<0.05). The trained swimmers showed significantly lower values for stroke length and velocity (p<0.05) during the swimming phase. Analysis revealed low intra-subject variability (across the 3 trials) but high inter-subject variability, indicating that both elite and trained swimmers had mastered distinct, though different, motor patterns.

Swim specialty affects energy cost and motor organization.

The purpose of this study was to analyse the effect of swimmer specialty on energy cost and motor organization. The stroking parameters (velocity, stroke rate, stroke length, stroke index) and the index of coordination (IdC) of 6 elite sprinters were compared with those of 6 elite long-distance swimmers during an incremental swimming exercise test (6x300 m separated by 30 s of passive recovery) that progressively increased the energy cost. Energy cost ( C), with its aerobic ( Caero) and anaerobic ( Canaero) components, was determined by measuring oxygen uptake (VO2) and blood lactate ([La]). Motor organization was assessed by analysis of video recordings from aerial and underwater side-view cameras. The results showed that throughout the test, both groups increased C, Canaero, stroke rate and IdC and decreased Caero and stroke length (all P<0.05). On the mean of the 300-m sets, sprinters had higher values for C (14.8 VS. 12.9 J x kg (-1).m (-1)), Canaero (33.8 VS. 23.4%), [La] (5.9 VS. 3.1 mmol x L (-1)), stroke length (2.31 VS. 2.28 m) and IdC (-11.2 VS. -21.7%) and lower values for Caero (66.2 VS. 79.6%), VO2 net (2 825 VS. 2 903 mL x min (-1)), stroke rate (0.55 VS. 0.62 Hz) and stroke index (2.96 VS. 3.19 m (2) x s (-1)) than long-distance swimmers (all P<0.05). For the same relative intensity, sprinters accumulated more lactate and swam more slowly than long-distance swimmers; they showed greater change in their arm coordination but their swimming economy was lower.

Arm coordination, power, and swim efficiency in national and regional front crawl swimmers.

The effects of skill level on index of arm coordination (IdC), mechanical power output (P(d)), and swim efficiency were studied in front crawlers swimming at different speeds. Seven national and seven regional swimmers performed an arms-only intermittent graded speed test on the MAD-system and in a free condition. The MAD-system measured the drag (D) and P(d). Swimming speed (v), stroke rate (SR), stroke length (SL), stroke index (SI), relative entry, pull, push, and recovery phase durations, and IdC were calculated. Swim efficiency was assessed from SI, the coefficient of variation of calculated hip intra-cyclic velocity variations (IVV), and the efficiency of propulsion generation, i.e., the ratio of v(2) to tangential hand speed squared (u(2)). Both groups increased propulsive continuity (IdC) and hand speed (u) and applied greater P(d) to overcome active drag with speed increases (p<.05). This motor organization adaptation was adequate because SI, IVV, and v(2)/u(2) were unchanged. National swimmers appeared more efficient, with greater propulsive continuity (IdC) and P(d) to reach higher v than regional swimmers (p<.05). The regional swimmers exhibited a higher u and lower SI, IVV, and v(2)/u(2) compared to national swimmers (p<.05), which revealed lower effectiveness to generate propulsion, suggesting that technique is a major determinant of swimming performance.

Does breathing disturb coordination in butterfly?

This study quantified the effects of breathing compared to non-breathing and "race pace" on arm to leg coordination in the butterfly stroke. Twelve elite male swimmers swam at four paces: 400 m, 200 m, 100 m and 50 m. The arm and leg stroke phases were identified by video analysis to calculate the total time gap (TTG), which is the sum of T1 (hands' entry in the water/high point of first kick), T2 (beginning of the hands' backward movement/low point of first kick), T3 (hands' arrival in a vertical plane to the shoulders/high point of second kick) and T4 (hands' release from the water/low point of second kick). Two strokes with breathing were compared to two strokes with breath-holding. The TTG was greater with breathing (23.3% VS. 19%), showing less propulsive continuity between arm and leg actions (p<0.05). This was due to the shorter downward leg kick and longer arm catch and upward leg kick that led to longer glide time. Conversely, breathing leads to greater coupling between the hand exit and the end of leg propulsion, which was due to a shorter arm push phase to facilitate the head exit to breathe.

Kinematical profiling of the front crawl start.

This study analysed the start phases of 15 elite front crawl swimmers, all specialists of sprint events. The first aim was to determine which phases were correlated with the 15-m start time. The features common to the sample of swimmers were then established and individual profiles were clustered. The subjects performed two 25-m trials at the 50-m race-pace using their preferential start technique (grab start). The kinematical analysis assessed the durations of the block, flight, entry, glide, leg kicking and full swimming phases to the 15-m mark. Stroking parameters and the index of arm coordination (IdC) were analysed for the swimming part (10-20 m) of the 25-m. Through the swimming part IdC increased while stroke length and velocity decreased (p<0.05). The relative durations of the aerial (block, flight), entry and underwater phases were correlated with start time. Inter-subject variability was observed, which suggests that various motor solutions were used for the start. Notably, four clusters led to a short 15-m start time: the leg kicking style, mixed "leg kicking/swimming" style, long glide style and short glide style.