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The Roland Morris Disability Questionnaire (RMDQ-24) and the VAS spine score have been regularly used to measure functional outcome in patients with back pain. The RMDQ-24 is primarily used in degenerative disease of the spine and the VAS Spine is used in trauma patients. The aim of this study is to compare these scores and to see if there is a correlation in patients with a traumatic thoracolumbar spinal fracture. Prospective cohort study comparing the RMDQ-24 and the VAS spine score in patients with a traumatic type A fracture thoracolumbar spine fracture. Fifteen non-operatively patients (group one) completed 118 questionnaires and 17 operatively treated patients (group two) completed 140 questionnaires. Group one scored an average of 6.6 and 65.9 for the RMDQ-24 and VAS Spine, in group two this was 5.1 and 82.9. Spearman's correlation test showed a significant correlation, in group one 0.83 and for the second group 0.87. RMDQ-24 and VAS Spine have a strong positive correlation in measuring disability in a group of patients with back pain because of a spinal fracture. In both non-operatively and operatively treated groups this correlation is significant. [ABSTRACT FROM AUTHOR]

Study Design: Systematic review., Objective: In 1994, the Load Sharing Classification (LSC) was introduced to aid the choice of surgical treatment of thoracolumbar spine fractures. Since that time this classification system has been commonly used in the field of spine surgery. However, current literature varies regarding its use and predictive value in relation to implant failure and sagittal collapse. The objective of this study is to assess the predictive value of the LSC concerning the need for anterior stabilization to prevent sagittal collapse and posterior instrumentation failure., Methods: An electronic search of PubMed, Medline, Embase, and the Cochrane Library was performed. Inclusion criteria were (1) cohort or clinical trial (2) including patients with thoracolumbar burst fractures (3) whose severity of the fractured vertebrae was assessed by the LSC., Results: Five thousand eighty-two articles have been identified, of which 21 articles were included for this review. Twelve studies reported no correlation between the LSC and sagittal collapse or instrumentation failure in patients treated with short-segment posterior instrumentation (SSPI). Seven articles found no significant relation; 5 articles found no instrumentation failure at all. The remaining 9 articles experienced failure in patients with a high LSC or recommended a different surgical technique., Conclusions: Although the LSC was originally developed to predict the need for anterior stabilization in addition to SSPI, many studies show that SSPI only can be sufficient in treating thoracolumbar fractures regardless of the LSC. The LSC might have lost its value in predicting sagittal collapse and posterior instrumentation failure., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2019.)

Using high-speed videography, we investigated how fruit flies compensate for unilateral wing damage, in which loss of area on one wing compromises both weight support and roll torque equilibrium. Our results show that flies control for unilateral damage by rolling their body towards the damaged wing and by adjusting the kinematics of both the intact and damaged wings. To compensate for the reduction in vertical lift force due to damage, flies elevate wingbeat frequency. Because this rise in frequency increases the flapping velocity of both wings, it has the undesired consequence of further increasing roll torque. To compensate for this effect, flies increase the stroke amplitude and advance the timing of pronation and supination of the damaged wing, while making the opposite adjustments on the intact wing. The resulting increase in force on the damaged wing and decrease in force on the intact wing function to maintain zero net roll torque. However, the bilaterally asymmetrical pattern of wing motion generates a finite lateral force, which flies balance by maintaining a constant body roll angle. Based on these results and additional experiments using a dynamically scaled robotic fly, we propose a simple bioinspired control algorithm for asymmetric wing damage.

The flight pattern of many fly species consists of straight flight segments interspersed with rapid turns called body saccades, a strategy that is thought to minimize motion blur. We analyzed the body saccades of fruit flies (Drosophila hydei), using high-speed 3D videography to track body and wing kinematics and a dynamically scaled robot to study the production of aerodynamic forces and moments. Although the size, degree and speed of the saccades vary, the dynamics of the maneuver are remarkably stereotypic. In executing a body saccade, flies perform a quick roll and counter-roll, combined with a slower unidirectional rotation around their yaw axis. Flies regulate the size of the turn by adjusting the magnitude of torque that they produce about these control axes, while maintaining the orientation of the rotational axes in the body frame constant. In this way, body saccades are different from escape responses in the same species, in which the roll and pitch component of banking is varied to adjust turn angle. Our analysis of the wing kinematics and aerodynamics showed that flies control aerodynamic torques during the saccade primarily by adjusting the timing and amount of span-wise wing rotation., (© 2015. Published by The Company of Biologists Ltd.)

The ability to regulate forward speed is an essential requirement for flying animals. Here, we use a dynamically-scaled robot to study how flapping insects adjust their wing kinematics to regulate and stabilize forward flight. The results suggest that the steady-state lift and thrust requirements at different speeds may be accomplished with quite subtle changes in hovering kinematics, and that these adjustments act primarily by altering the pitch moment. This finding is consistent with prior hypotheses regarding the relationship between body pitch and flight speed in fruit flies. Adjusting the mean stroke position of the wings is a likely mechanism for trimming the pitch moment at all speeds, whereas changes in the mean angle of attack may be required at higher speeds. To ensure stability, the flapping system requires additional pitch damping that increases in magnitude with flight speed. A compensatory reflex driven by fast feedback of pitch rate from the halteres could provide such damping, and would automatically exhibit gain scheduling with flight speed if pitch torque was regulated via changes in stroke deviation. Such a control scheme would provide an elegant solution for stabilization across a wide range of forward flight speeds.

Avoiding predators is an essential behavior in which animals must quickly transform sensory cues into evasive actions. Sensory reflexes are particularly fast in flying insects such as flies, but the means by which they evade aerial predators is not known. Using high-speed videography and automated tracking of flies in combination with aerodynamic measurements on flapping robots, we show that flying flies react to looming stimuli with directed banked turns. The maneuver consists of a rapid body rotation followed immediately by an active counter-rotation and is enacted by remarkably subtle changes in wing motion. These evasive maneuvers of flies are substantially faster than steering maneuvers measured previously and indicate the existence of sensory-motor circuitry that can reorient the fly's flight path within a few wingbeats.

In closed-loop systems, sensor feedback delays may have disastrous implications for performance and stability. Flies have evolved multiple specializations to reduce this latency, but the fastest feedback during flight involves a delay that is still significant on the timescale of body dynamics. We explored the effect of sensor delay on flight stability and performance for yaw turns using a dynamically scaled robotic model of the fruitfly, Drosophila. The robot was equipped with a real-time feedback system that performed active turns in response to measured torque about the functional yaw axis. We performed system response experiments for a proportional controller in yaw velocity for a range of feedback delays, similar in dimensionless timescale to those experienced by a fly. The results show a fundamental trade-off between sensor delay and permissible feedback gain, and suggest that fast mechanosensory feedback in flies, and most probably in other insects, provide a source of active damping which compliments that contributed by passive effects. Presented in the context of these findings, a control architecture whereby a haltere-mediated inner-loop proportional controller provides damping for slower visually mediated feedback is consistent with tethered-flight measurements, free-flight observations and engineering design principles.

Background: Spinal fractures can be an important cause for disabling back pain. Therefore, in judging the cost-effectiveness of nonsurgical or surgical therapy, not only direct costs but also the indirect costs should be calculated. In this prospective randomized study, the costs incurred by nonsurgically and surgically treated patients with a traumatic thoracolumbar spine fracture without neurological involvement were analysed., Materials and Methods: 32 patients with a traumatic thoracolumbar spine fracture were prospectively randomized for operative or nonsurgical treatment. Patients were sent a questionnaire every three months to inquire about work-status, additional health costs and doctor visits. The patients who have minimum followup of two years were included., Results: Of thirty-two patients, 30 met the criterion of the followup period of at least two years. Fourteen patients received nonsurgical therapy, while 16 received surgical treatment. Direct costs of the treatment of nonsurgically treated patients were €10,608 ($12,730). For the operatively treated group, these costs were €18,769 ($22,523). Indirect costs resulted in a total of €219,187 ($263,025) per nonoperatively treated patient. In the operatively treated group, these costs were €66,004 ($79,206)., Conclusion: In the treatment of traumatic thoracolumbar spine fractures, the indirect costs exceed the direct costs by far and make up 95.4% of the total costs for treatment in nonsurgically treated patients and 71.6% of the total costs in the operative group. In view of cost-effectiveness, the operative therapy of traumatic thoracolumbar spine fractures is to be preferred.

Study Design: Multicenter prospective randomized trial., Objective: To test the hypotheses that thoracolumbar AO Type A spine fractures without neurologic deficit, managed with short-segment posterior stabilization will show an improved radiographic outcome and at least the same functional outcome as compared with nonsurgically treated thoracolumbar fractures., Summary of Background Data: There are various opinions regarding the ideal management of thoracolumbar Type A spine fractures without neurologic deficit. Both operative and nonsurgical approaches are advocated., Methods: Patients were randomized for operative or nonsurgical treatment. Data sampling involved demographics, fracture classifications, radiographic evaluation, and functional outcome., Results: Sixteen patients received nonsurgical therapy, and 18 received surgical treatment. Follow-up was completed for 32 (94%) of the patients after a mean of 4.3 years. At the end of follow-up, both local and regional kyphotic deformity was significantly less in the operatively treated group. All functional outcome scores (VAS Pain, VAS Spine Score, and RMDQ-24) showed significantly better results in the operative group. The percentage of patients returning to their original jobs was found to be significantly higher in the operative treated group., Conclusions: Patients with a Type A3 thoracolumbar spine fracture without neurologic deficit should be treated by short-segment posterior stabilization.

Study Design: Retrospective study and review of literature., Objectives: Study of demographic data concerning spinal fractures caused by horse riding, classification of fractures according to the AO and Load Sharing classifications, evaluation of mid-term radiological results and long-term functional results., Methods: A review of medical reports and radiological examinations of patients presented to our hospital with horse riding-related spine fractures over a 13-year period; long-term functional follow-up is performed using the Roland Morris Disability Questionnaire (RMDQ-24)., Results: Thirty-six spine fractures were found in 32 patients. Male to female ratio is 1:7. Average age is 33.7 years (8-58 years). The majority of the fractures (78%) are seen at the thoracolumbar junction Th11-L2. All but two patients have AO type A fractures. The average Load Sharing Classification score is 4.9 (range 3-9). Neurological examinations show ASIA/Frankel E status for all patients. Surgical treatment is performed on ten patients. Mean follow-up for radiological data is 15 months (range 3-63). Functional follow-up times range from 1 to 13 years with an average follow-up of 7.3 years. Mean RMDQ-24 score for all patients is 5.5 (range: 0-19), with significantly different scores for the non-operative and surgical group: 4.6 vs 8.1. Twenty-two percent of the patients have permanent occupational disabilities and there is a significant correlation between occupational disability and RMDQ-24 scores., Conclusions: Not only are short-term effects of spine fractures caused by horse riding substantial but these injuries can also lead to long-term disabilities.

We investigated the effects of low frequency fatigue (LFF) on post-exercise changes in rectified surface EMG (rsEMG) and single motor unit EMG (smuEMG) in vastus lateralis muscle (n = 9). On two experimental days the knee extensors were fatigued with a 60-s-isometric contraction (exercise) at 50% maximal force capacity (MFC). On the first day post-exercise (15 s, 3, 9, 15, 21 and 27 min) rsEMG and electrically-induced (surface stimulation) forces were investigated. SmuEMG was obtained on day two. During short ramp and hold (5 s) contractions at 50% MFC, motor unit discharges of the same units were followed over time. Post-exercise MFC and tetanic force (100 Hz stimulation) recovered to about 90% of the pre-exercise values, but recovery with 20 Hz stimulation was less complete: the 20-100 Hz force ratio (mean +/- SD) decreased from 0.65+/-0.06 (pre-exercise) to 0.56+/-0.04 at 27 min post-exercise (P<0.05), indicative of LFF. At 50% MFC, pre-exercise rsEMG (% pre-exercise maximum) and motor unit discharge rate were 51.1 +/- 12.7% and 14.1 +/- 3.7 (pulses per second; pps) respectively, 15 s post-exercise the respective values were 61.4 +/- 15.4% (P<0.05) and 13.2 +/- 5.6 pps (P>0.05). Thereafter, rsEMG (at 50% MFC) remained stable but motor unit discharge rate significantly increased to 17.7 +/- 3.9 pps 27 min post-exercise. The recruitment threshold decreased (P<0.05) from 27.7 +/- 6.6% MFC before exercise to 25.2 +/- 6.7% 27 min post-exercise. The increase in discharge rate was significantly greater than could be expected from the decrease in recruitment threshold. Thus, post-exercise LFF was compensated by increased motor unit discharge rates which could only partly be accounted for by the small decrease in motor unit recruitment threshold.

The purpose of the present study was to relate the expected inter-subject variability in voluntary drive of the knee extensor muscles during a sustained isometric contraction to the changes in firing rates of single motor units. Voluntary activation, as established with superimposed electrical stimulation was high (range: 91-99%, n=8) during a short maximal contraction, but was lower (range: 69-100%) in most subjects at the point of force failure during a sustained (49.1+/-10.1 s) fatiguing contraction at 50% of maximum force. On a different experimental day the firing behaviour of 27 single motor units was recorded with wire electrodes in the vastus lateralis muscle, 24 of which could be monitored from the time of recruitment to the point of force failure (53.6+/-9.8 s). Motor unit firing behaviour differed considerably among subjects. During the second half of the sustained, fatiguing contraction the changes in firing rate firing rate variability of early recruited units ranged from -10% to +100% and from -50% to +160% respectively among subjects. There were significant positive linear relations between voluntary activation, on the one hand, and rectified surface electromyogram (rsEMG, r=0.82), the changes in motor unit firing rate ( r=0.49) and firing rate variability ( r=0.50) towards the point of force failure on the other. The present data suggest that differences in voluntary drive that appear among subjects during fatigue may be an important determinant of motor unit firing behaviour.

The effect on drag of a Speedo Fast-skin suit compared to a conventional suit was studied in 13 subjects (6 males, 7 females) swimming at different velocities between 1.0 and 2.0 m.s-1. The active drag force was directly measured during front crawl swimming using a system of underwater push-off pads instrumented with a force transducer (MAD system). For a range of swimming speeds (1.1, 1.3, 1.5 and 1.7 m.s-1), drag values were estimated. On a group level, a statistically non-significant drag reduction effect of 2% was observed for the Fast-skin suit (p = 0.31). Therefore, the 7.5% reduction in drag claimed by the swimwear manufacturer was not corroborated.