Michael Bachmann Nielsen

Effectiveness of active physical training as treatment for long-standing adductor-related groin pain in athletes: randomised trial

BACKGROUND Groin pain is common among athletes. A major cause of long-standing problems is adductor-related groin pain. The purpose of this randomised clinical trial was to compare an active training programme (AT) with a physiotherapy treatment without active training (PT) in the treatment of adductor-related groin pain in athletes. METHODS 68 athletes with long-standing (median 40 weeks) adductor-related groin pain--after examination according to a standardised protocol--were randomly assigned to AT or PT. The treatment period was 8-12 weeks. 4 months after the end of treatment a standardised examination was done. The examining physician was unaware of the treatment allocation. The ultimate outcome measure was full return to sports at the same level without groin pain. Analyses were by intention to treat. FINDINGS 23 patients in the AT group and four in the PT group returned to sports without groin pain (odds ratio, multiple-logistic-regression analysis, 12.7 [95% CI 3.4-47.2]). The subjective global assessments of the effect of the treatments showed a significant (p=0.006) linear trend towards a better effect in the AT group. A per-protocol analysis did not show appreciably different results. INTERPRETATION AT with a programme aimed at improving strength and coordination of the muscles acting on the pelvis, in particular the adductor muscles, is very effective in the treatment of athletes with long-standing adductor-related groin pain. The potential preventive value of a short programme based upon the principles of AT should be assessed in future, randomised, clinical trials.

Preventive Effect of Eccentric Training on Acute Hamstring Injuries in Men’s Soccer: A Cluster-Randomized Controlled Trial

Background: The incidence of acute hamstring injuries is high in several sports, including the different forms of football. Purpose: The authors investigated the preventive effect of eccentric strengthening of the hamstring muscles using the Nordic hamstring exercise compared with no additional hamstring exercise on the rate of acute hamstring injuries in male soccer players. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Fifty Danish male professional and amateur soccer teams (942 players) were allocated to an intervention group (461 players) or a control group (481 players). Players in the intervention group conducted a 10-week progressive eccentric training program followed by a weekly seasonal program, whereas players in the control group followed their usual training program. The main outcome measures were numbers of overall, new, and recurrent acute hamstring injuries during 1 full soccer season. Results: Fifty-two acute hamstring injuries in the control group compared with 15 injuries in the intervention group were registered. Comparing intervention versus the control group, overall acute hamstring injury rates per 100 player seasons were 3.8 versus 13.1 (adjusted rate ratio [RR], 0.293; 95% confidence interval [CI], 0.150-0.572; P < .001). New injury rates per 100 player seasons were 3.1 versus 8.1 (RR, 0.410; 95% CI, 0.180-0.933; P = .034), whereas recurrent injury rates per 100 player seasons were 7.1 versus 45.8 (RR, 0.137; 95% CI, 0.037-0.509; P = .003). Number needed to treat [NNT] to prevent 1 acute hamstring injury (new or recurrent) is 13 (95% CI, 9-23) players. The NNT to prevent 1 new injury is 25 (95% CI, 15-72) players, and NNT to prevent 1 recurrent injury is 3 (95% CI, 2-6) players. Conclusion: In male professional and amateur soccer players, additional eccentric hamstring exercise decreased the rate of overall, new, and recurrent acute hamstring injuries.

High frame-rate blood vector velocity imaging using plane waves: Simulations and preliminary experiments

Conventional ultrasound methods for acquiring color images of blood velocity are limited by a relatively low frame-rate and are restricted to give velocity estimates along the ultrasound beam direction only. To circumvent these limitations, the method presented in this paper uses 3 techniques: 1) The ultrasound is not focused during the transmissions of the ultrasound signals; 2) A 13 -bit Barker code is transmitted simultaneously from each transducer element; and 3) The 2-D vector velocity of the blood is estimated using 2-D cross-correlation. A parameter study was performed using the Field II program, and performance of the method was investigated when a virtual blood vessel was scanned by a linear array transducer. An improved parameter set for the method was identified from the parameter study, and a flow rig measurement was performed using the same improved setup as in the simulations. Finally, the common carotid artery of a healthy male was scanned with a scan sequence that satisfies the limits set by the Food and Drug Administration. Vector velocity images were obtained with a frame-rate of 100 Hz where 40 speckle images are used for each vector velocity image. It was found that the blood flow approximately followed the vessel wall, and that maximum velocity was approximately 1 m/s, which is a normal value for a healthy person. To further evaluate the method, the test person was scanned with magnetic resonance (MR) angiography. The volume flow derived from the MR scanning was compared with that from the ultrasound scanning. A deviation of 9% between the 2 volume flow estimates was found.

Intraobserver and interobserver variations in sonographic measurements of kidney size in adult volunteers. A comparison of linear measurements and volumetric estimates.

Estimation of renal size by sonography can be performed by measuring renal length, volume, cortical volume or cortical thickness. Observer variation in these measurements is an important factor, especially when repeated measurements are compared. This study was performed to examine the magnitude of intraobserver and interobserver variations for each of the above-mentioned measurements, and to find the measurement with the lowest observer variation. Sonographic measurements were performed by 3 observers on 18 adult volunteers. The standard deviation of the difference (SDD) between any 2 pairs of measurements was used as the indicator of the magnitude of the observer variation. Renal length measurement showed the lowest observer variation with a relative SDD of 4 to 5%. Measurement of cortical thickness showed the poorest reproducibility with a relative SDD of 18 to 23%, while volumetric estimations had a relative SDD of 14 to 17%. Renal length measurement should be preferred to renal volume estimation, especially when comparing repeated measurements.

Risk of sphincter damage and anal incontinence after anal dilatation for fissure-in-ano

Follow-up was performed two to six years after anal dilatation for fissure-in-ano in 32 consecutive patients who had not undergone additional anal surgery. All patients were interviewed and asked specifically about impairment of flatus or fecal control and its possible relation to the anal dilatation. Anal dilatation was followed by minor anal incontinence in 12.5 percent of the patients. Anal endosonographic follow-up was accepted by 20 patients, and sphincteric defects were found in 13 (65 percent) of those. Two patients with anal incontinence had internal sphincter defects. Sphincteric defects were also found in 11 of the 18 continent patients who underwent sonography: internal sphincter defects in nine, external sphincter defect in one, and combined defects of both sphincter muscles in one. In conclusion, anal dilatation results in sphincter damage in more than half of patients, but few of them develop anal incontinence.

Anal sphincter size measured by endosonography in healthy volunteers. Effect of age, sex, and parity.

The anal sphincter muscles consist of the circular internal and external sphincters together with the sling-shaped associated puborectalis muscle. Ten men, 10 women with no vaginal deliveries, and 10 women with one or more vaginal deliveries were studied with anal endosonography using a 7 MHz multiplanar endoprobe. The thickness of the internal sphincter and the thickness, length, and cross-sectional area of the external sphincter were measured and related to age, sex, and parity. Reproducibility was assessed by similar measurements on different days in 10 volunteers. Anal sphincter size was the same in men and women and was not affected by the number of child births. Internal sphincter muscle thickness increased with age. Anal manometry and electromyography with an anal sponge were performed in all volunteers but the results did not correlate to any of the anal sphincter dimensions. Our conclusion is that although there are some limitations, endosonography can be used to determine the size of the anal sphincter muscles.

Sonographic measurement of the thymus in infants

A new method of measuring the size of the thymus in infants less than 1 year of age is presented. The width of the thymus was measured in a transverse image while the area of the largest lobe was assessed in a longitudinal image. The thymic index was then defined as the product of these two values. Intra-and interobserver variation analysis were performed in 23 infants. Each infant was scanned alternately by both of two radiologists, and later the same day the measurements were repeated. The mean differences between the first and second measurements (intraobserver variation) were −0.25 (2 SD 7.56) and −1.13 (2 SD 10.80), respectively, for the two observers. The mean difference between the first measurements of the two observers (interobserver variation) was 1.47 (2 SD 9.39). In a postmortem study of 12 infants the thymic index measured by sonography showed an acceptable correlation to the actual volume (c = 0.80) and weight (c = 0.87) of the thymus. In conclusion, our sonographic estimate of the volume of the thymus, the thymic index, in infants under 8 months of age seems to be easy, reliable and reproducible.

Ultrasonic colour Doppler imaging

Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been found to be of great value in assessing blood flow in many clinical conditions. Although the method for obtaining the velocity information is in many ways similar to the method for obtaining the anatomical information, it is technically more demanding for a number of reasons. It also has a number of weaknesses, perhaps the greatest being that in conventional systems, the velocities measured and thus displayed are the components of the flow velocity directly towards or away from the transducer, while ideally the method would give information about the magnitude and direction of the three-dimensional flow vectors. This review briefly introduces the principles behind colour Doppler imaging and describes some clinical applications. It then describes the basic components of conventional colour Doppler systems and the methods used to derive velocity information from the ultrasound signal. Next, a number of new techniques that seek to overcome the vector problem mentioned above are described. Finally, some examples of vector velocity images are presented.

Endosonographic assessment of the anal sphincter after surgical reconstruction

PURPOSE: Patients with anal incontinence attributable to trauma are usually treated by sphincter reconstruction. Failures because of incomplete reconstruction may possibly be detected by anal endosonography which gives detailed information on the anal sphincter muscles. The aim of this study was to describe the endosonographic findings in patients after sphincter reconstruction. MATERIALS AND METHODS: Ten female patients who had undergone surgical sphincter reconstruction using an overlapping technique because of anal incontinence were studied with anal endosonography a median of six months after surgery. Five patients were fully continent, three were incontinent for flatus, and two patients were still incontinent for solid stool at the time of this study. Eight patients had also been studied with endosonography before surgery, and, in these patients, we compared the initial sonograms with the follow-up sonograms. The angular extent of the endosonographic defects in the external sphincter before and after reconstruction was measured in degrees and compared with the outcome of surgery. RESULTS: After reconstruction, continuity of the external anal sphincter was completely restored at all levels in four patients, one of whom still had anal incontinence. Continuity was partially restored in three patients: two were fully continent, while one patient, previously incontinent for stool, was incontinent for flatus. In three patients the continuity was restored at one level but a persisting defect was found at a different level. In two of these patients the grade of incontinence was unchanged. Three patients also had defects in the internal anal sphincter. CONCLUSION: After surgical sphincter reconstruction for anal incontinence, we found sphincteric defects in six patients, including four of five patients who still had some degree of incontinence. Thus, endosonography may be used for postoperative assessment and may explain the unsatisfactory results of surgery in some patients. We recommend that endosonography be also performed preoperatively, whereby the effect of the operation on the size of the sphincteric defect can be assessed.

Comparison of Real-Time In Vivo Spectral and Vector Velocity Estimation

The purpose of this study is to show whether a newly introduced vector flow method is equal to conventional spectral estimation. Thirty-two common carotid arteries of 16 healthy volunteers were scanned using a BK Medical ProFocus scanner (DK-2730, Herlev, Denmark) and a linear transducer at 5 MHz. A triplex imaging sequence yields both the conventional velocity spectrum and a two-dimensional vector velocity image. Several clinical parameters were estimated and compared for the two methods: Flow angle, peak systole velocity (PS), end diastole velocity (ED) and resistive index (RI). With a paired t-test, the spectral and vector angles did not differ significantly (p = 0.658), whereas PS (p = 0.034), ED (p = 0.004) and RI (p < 0.0001) differed significantly. Vector flow can measure the angle for spectral angle correction, thus eliminating the bias from the radiologist performing the angle setting with spectral estimation. The flow angle limitation in velocity estimation is also eliminated, so that flow at any angle can be measured.