Ultraschalltherapie der Epikondylopathia humeri - Immediate und serielle Wirkungen auf die Druckschmerzschwelle

Abstract

Immediate und serielle Wirkungen auf die Druckschmerzschwelle Ultrasound therapy of epicondylopathia humeri -immediate and serial treatment effects on the pressure pain threshold: Ultrasound has been used since decades for the treatment of painful musculoskeletal disorders, with high doses up to 3W/cm2. Since the 8Oies a tendency to low dose treatment (0.1 -1 W/cm2) can be observed. In the same period a growing number of investigations and reviews with negative resuits were published, which severely throw doubt on the therapeutical effectiveness of therapeutical ultrasound. Objective: Objective of this study were informations concerning immediate-, serial-and intensity dependent effects of ultrasound therapy. Being a classical indication for ultrasound therapy, the epicondylitis (,,tennis elbow") has been chosen as a model disorder. Methods: 30 patients with chronical epicondylitis (21, 9 m) were randomly assigned to 3 treatment groups. Each patient received a 6 mm treatment on 5 consecutive days. The low dose group received 0.3W/cm2; the placebo group 0W/cm2. Both groups were double blinded. The high dose group was treated by individual doses, causing a painless sensation of heat (mean: 1.2 W/cm2). This group therefore was not blinded. For measurement of the pressure pain threshold (PPT) an automatic device has been established, which developed a linear increasing force (1 kp/s) until the beginning of a painful sensation. The PPT was measured before, and a mm, 5 mm and 10 mm after treatment. A follow-up took place 5 days after the last treatment (day 10), combined with a visual analogue scale (VAS) measurement. Results: Immediat effects: Only the high dose therapy lead to a short PPT increase compared to initial values (÷ 0.28 kp; p = 0.03), but not compared to control. Serial effects: Only high dose therapy showed an increase of PPT. This effect, however, was only at follow-up (day 10) of statistical and clinical significance (+ 0.73 kp; p = 0.015). A similar result showed the VAS pain rating score (-34%; p = 0.002). Conclusions: The results lead to the conclusion, that ultrasound has no immediate analgesic effects of clinical relevance. However, serial high dose ultrasound treatment reveals a remarkable pain reduction within some days of delay, maybe due to a curative heat stimulus. Consequences, as well for practical treatment as for design and evaluation of studies, should be taken. Investigations with rather low dose treatment and/or without follow up control maybe respon-Phys sible for some negative judgements of ultrasound therapy effectiveness in the recent literature.Zusammenfassung: Während Ultraschall jahrzehntelang mit lntensitäten bis zu 3W/cm2 zur Behandlung muskuloskelettaler Schmerzen angewendet wurde, ist seit den 8Oer jahren eine Tendenz zu wesentlich niedrigeren Dosierungen (ca. 0,1 -1 W/ cm2) zu beobachten. Parallel hierzu mehren sich Untersuchungen und Reviews mit negativen Ergebnissen, weiche den therapeutischen Nutzen von Ultraschall zunehmend in Zweifel ziehen. Ziel: Ziel der Arbeit war d...