Chapter 1 Introduction: current concepts and clinical decision making in electrotherapy

Clinical decision making in electrotherapy 9

INTRODUCTION

Electrotherapy has a long-established place in therapy practice, being one of the mainstays of professional activity over many years. The emphasis on this mode of intervention has gone through significant changes over time and, in current practice, it is seen for the most part as an adjunct to treatment rather than as a means to an end in isolation. There are instances where it can be rightly considered to be the focus of the treatment but this is unusual and, arguably, the exception rather than the rule.

Given that many of the modalities that have been used in the past have waned in popularity, and that every year new machines and new ‘treatments’ come to the marketplace, it can be difficult for the therapist to know whether this ‘new’ treatment is in fact new or just a revamped version of an already existing intervention. There are undoubtedly new interventions and certainly new approaches to existing treatments, driven by a demand from patients, from manufacturers and from research. To claim that all current electrotherapy practice is ‘evidence based’ would be naïve, although there is room for debate as to what actually constitutes evidence-based practice, from where the evidence is sourced and the role of individual experience and that of colleagues in that process. Some of these issues will be explored in this introductory chapter.

From the published and experiential evidence, it appears that electrotherapy can be clinically effective and need not be written off as something that is ‘old fashioned’ and that no longer deserves a place in the therapeutic tool kit. That it can be applied in a clinically effective manner is evidenced in the chapters that follow. That it can also be delivered in an ineffectual manner is something that will be recognised by practitioners from many disciplines. The evidence would suggest that when the appropriate modality is applied at the ‘right’ dose for the presenting problem, it can make a significant contribution to the improvement and well being of the patient. The fact that it does not work in all cases is not surprising at all. This would be a common feature of any therapy – whether manual therapy, exercise or drug therapy. If one were to use a particular manual therapy technique for patient X, and the next day or the next week, when X returns, there was no improvement, it would not mean that all manual therapy was a waste of time, or even that the therapist was incompetent. There are patients who fail to respond to therapy A, but do very well with therapy B. The reasons for these individual differences are poorly understood, but certainly add to the richness of clinical experience. If therapy was simply a matter of applying the right recipe to the patient presenting with a given problem, clinical practice would lose a deal of its attractiveness. For any therapeutic intervention to be effective there is the need for a clear assessment, a rationalisation of the problem(s), and the construction of a proposed treatment plan that matches the needs of the individual taking into account their holistic circumstances, not just their presenting signs and symptoms. The applied intervention is that which is deemed to be most likely to be effective. This is no guarantee that there will be 100% success, but the best odds for a beneficial outcome. The thinking therapist then re-evaluates the outcomes as the treatment progresses, modifying the treatment package in the light of these results.

One of the problems with the application of research in electrotherapy, as well as in other fields, is that the research tends to be somewhat reductionist in approach. A clinical trial that evaluates, for example, the effect of ultrasound for patients with a tear of the medial collateral ligament of the knee, aims to construct a methodology that readily identifies the contribution that ultrasound makes to the clinical outcome. By keeping all other treatment parameters ‘constant’ – the advice, exercise, manual therapy, environment, number of treatment and treatment intervals – the real effect of the ultrasound therapy can be evaluated.

The clinical reality is that it is the package of care that is clinically effective (or not), rather than any one individual component of it. If a patient has received several forms of intervention (e.g. some advice, electrotherapy, manual therapy and exercise coupled with appropriate advice and education) and comes back for the next session with an improvement, it is extraordinarily difficult to know which elements of the treatment package (if any) were responsible for the change. It could be that all were necessary in that particular combination; it could be that one could have been safely omitted and the equivalent outcome would have been achieved.

When making a clinical decision, practitioners will put together the package that in their opinion is most likely to be effective for that patient. Some patients will not take advice well, others will almost certainly not undertake the exercises that are suggested, and others might have a strong aversion to the idea of electrical stimulation. The effective package is the one that matches the patient’s presentation and the treatment context. Some patients might be treated several times a week whereas others can only be seen once every 2 or 3 weeks on a ‘check-up’ basis. Package tailoring is an essential skill for any therapist.

The current stage of research in electrotherapy and many other therapeutic fields is still at the point where the building blocks of these packages are being evaluated. We might know, in absolute terms, the effect of this particular treatment, at this particular dose on a specific problem in a controlled research environment. We might not know what happens when the same therapy is used in a different combination – there are almost too many variables to evaluate at the current time.

The research evidence suggests that electrotherapy can be effective as an element of treatment. Further work is needed to evaluate the combinations – or treatment packages – that are most effective. Practitioners will have, from their own experience, ideas about combinations that are more or less effective. This is the source of the richness of therapeutic experience and until substantially more work has been completed – both in the laboratory and in clinical practice, using reductionist, holistic and pragmatic methodologies – the full story is unlikely to emerge.

The intention of this publication is to provide a review of the background, evidence and clinical applicability of various modalities in use. The authors of each chapter are writing because they know their subject and, although there might be gaps in the knowledge that deserve to be filled, there is sufficient evidence out there from which clinical decision making can be enhanced and further developments achieved.

CURRENT CONCEPTS IN ELECTROTHERAPY

No matter which classification one uses, there is no one correct way to divide and categorise the range of electrotherapy modalities available. One could for example use a thermal/non-thermal division, but reading the literature on thermal vs. non-thermal vs. microthermal will soon demonstrate that this is an almost certainly flawed proposition. One could attempt to categorise by type of applied energy: light (e.g. laser, ultraviolet) versus electrical stimulation (e.g. transcutaneous electrical nerve stimulation [TENS], interferential) versus the high-frequency radiations (shortwave, microwave). Ultrasound would have to sit in a category of its own and biofeedback would not belong anywhere in that, for the most part, it does not involve the delivery of energy but enables the patient to respond to the behaviour of his or her body. This division could also be challenged in that, for example, the effects of continuous shortwave are similar but clinically different from those of pulsed shortwave. The fundamental energy might be the same but the mode of delivery makes a substantial difference to the treatment outcome.

Furthermore, there is an issue with the inclusion of ‘new’ therapies into the classification. Magnetic therapy is a swiftly developing field although, one would suggest, still in its clinical infancy. Should it have a category of its own or should it be incorporated with some forms of shortwave that employ and electromagnetic field?

The modalities covered in this text include those that are in common clinical use, and have been divided into sections that reflect the type of energy employed, for example, the thermal energies are grouped as are various forms of electrical stimulation. The grouping of laser, ultrasound and biofeedback does not imply a common energy type or mode of action, but rather their individuality.

MODELS OF ELECTROTHERAPY

All electrotherapy modalities – whether in current use, abandoned from the past or yet to be ‘invented’ – actually follow a very straightforward model that is presented below. It is sufficiently robust to explain current practice, yet sufficiently flexible to incorporate future developments. It has been refined over the years and will almost certainly be subject to further refinement in the future.

In principle, the model identifies that the delivery of energy from a machine or device is the start point of the intervention (Fig. 1.1). The energy entry to the tissues results in a change in one or more physiological events. Some are very specific whereas others are multifaceted. The capacity of the energy to influence physiological events is key to the processes of all electrotherapy modalities and will be reflected throughout this publication. The physiological shift that results from the energy delivery is used in practice to generate what is commonly referred to as a therapeutic effect.