Dry needling: A critical commentary of its effectiveness and safety profile

As clinicians we are regularly faced with the conundrum of how best to safely treat our patient’s pain and musculoskeletal dysfunction. A recent study has shown that the commonest reasons for patients seeking community physiotherapy assessment is for pain relief (89%) and improved function (93%) [1]. Dry needling is becoming a widely used tool in many physiotherapists armoury for aiding with these complaints. Despite its rate of growth there still remains questions marks over the effectiveness of dry needling and its potential to cause adverse events [2–7]. This critical commentary aims to highlight the latest evidence for treating patient’s pain and musculoskeletal dysfunction with dry needling while also focusing on some of the possible adverse events and how these may be avoided and recognised early.

Dry needling is an invasive procedure using solid filament needles to treat myofascial pain and dysfunction. The process was first described in the works of Dr Janet Travel who pioneered many of the concepts and theories around dry needling. These can be read in her Autobiography ‘Office hours: day and night. The autobiography of Janet Travell MD’. The process of dry needling was modernised and brought to the world of scientific literature by Lewitt in 1979 [8]. He described the ‘needle effect’ where 86% of his patients experienced an immediate analgesic effect when the needle was inserted to the most painful location on the muscle.

There has been extensive publications describing various dry needling treatment philosophies and models of care since [8–10]. The most common model of treatment describes the treatment of myofascial pain by identifying and needling myofascial trigger points. This model has become so entrenched with the phrase dry needling that the position statement from the US states board of Physical Therapy categorised dry needling as the process of isolated treatment of myofascial trigger points [11]. Myofascial trigger points (MTP) are described as an irritable, taut band of myofacia/muscle which can cause pain, tenderness and altered motor function [12]. One of the theories around the development of MTPs is that chronic shortening of the sarcomere along with autonomic changes leads to localised ischaemia [13], as a result local inflammatory cells are released which sensitize the sensory nervous system [14]. When compressed, these points elicit a characteristic pain response in the patient.

The growing popularity of dry needling has stemmed from some positive initial studies. Lewitt’s first study stated treatment demonstrated immediate pain benefits in 86% of his patients [8]. Other positive studies have followed, with some in particular showing its effectiveness in comparison to wet injection therapy with lidocaine [15]. Despite this the effectiveness of dry needling for treating patient’s pain and disability continues to be debated [3–5]. The range of high quality evidence is unfortunately sparse. This is due to the inherent difficulties in blinding patients and no standardised approach for duration or location of treatment currently exists. Recent reviews largely agree that there is an improvement in the patients pain and range of motion in the short term when compared to no treatment, but evidence remains inconclusive for long term effects [3–5, 16]. There has also been some benefit seen in the medium term when treating neck and shoulder pain and dysfunction [17]. Interestingly there remains insufficient evidence to show superiority of dry needling when compared to other adjuncts to physical therapy [5, 18].

One of the main reasons for the inconsistencies in results is that there is no firm consensus on what is the most appropriate needling technique [19]. Many authors and practitioners feel the most appropriate technique is one that elicits a local twitch response (LTR) [20, 21]. A local twitch response is a visible contraction of part of the taut band of muscle involved following mechanical stimulation [22]. The importance of eliciting a local twitch response has been largely adopted by practitioners and guidelines [23], but continues to be debated in literature. There have been six studies specifically looking at the importance of eliciting a LTR and its effect on patients pain [20, 24–27]. Three of these studies observed a more significant reduction in patient’s pain following observation of a local twitch response [20, 24]. The remaining studies showed none or only weak correlation between LTR and improved analgesic effect [25–27]. Once again there was a relatively short follow up period of four weeks or less in all the studies involved. No study showed an improvement in disability in patients experiencing a LTR compared to those who didn’t.

Treating clinicians should receive appropriate training and certification to provide dry needling therapies. Guidelines differ between professional bodies and treatment jurisdictions. Levels of training are also dependent on what area of the body is to receive the treatment. For dry needling of trigger points in particular, appropriate training is required to reliably identify trigger points themselves, as this has been shown to be affected by clinicians level of training and experience [28]. Appropriate certification in Ireland involves a minimum of one three day introductory course [23]. This course focuses on recognising the importance of myofascial pathology and the identification of myofascial trigger points in particular. This is then followed by dry needling sessions highlighting appropriate safety measures and various needling techniques for particular body regions. Further training and certification is required to perform dry needling of specific high risk body regions such as thorax and para spinal muscles [23]. There has been a dramatic increase in dry needling certification course in the recent years. It is important for patient safety and personal insurance that practitioners follow the certification guidance of their local professional body.

Dry needling is invasive and should be seen as an adjunct to regular physical therapy assessment and treatment in suitable patients who have been carefully identified. Clinicians need to have an appropriate indication for providing dry needling therapy while also determining whether the therapy will place the patient under any unacceptable risk of adverse events. Dry needling is a relatively new addition to physical therapy and as a result much of the data regarding adverse events is based on studies from traditional acupuncture [29, 30]. Although this is helpful, it is not totally sufficient, as important differences exist between the two processes in terms of training and clinical practice. Dry needling tends to involve deeper insertion of the needles with dynamic movements, compared to acupuncture inserting needles to the acupoint only and needles are manipulated gently until a ‘deqi’ is achieved [31].

An Irish paper was the first beyond the level of case study to report on adverse events following dry needling [7]. In this paper the rate of mild adverse events was 19.18%. The most common adverse events experienced were bleeding, bruising and pain during or following treatment. There were no serious adverse events observed in this study, with a subsequent estimated rate of less than or equal to 0.04%. Some of the critiques of this study are that it did not reach the target level of patient interactions required to witness a serious adverse event. Serious events tend to be much less common than milder post procedural complications when looking at acupuncture literature [29, 30]. The adverse events were also reported by the practitioners themselves and this self-reporting introduces bias as complications may be underreported. This may be to avoid perceived negligence or because the adverse event has a delayed onset and the practitioner remains unaware of its occurrence. This is a well-documented phenomenon in relation to pneumothorax in particular [32, 33].

Studies involving traditional acupuncture show similar results to the study by Brady et al 2014 [7], adverse events are not uncommon in acupuncture but are less than documented in the study on dry needling 8.6% vs 19.18% [7, 29]. The most common adverse events are once again bleeding, bruising and pain. The estimated range of serious adverse events during acupuncture therapy is between 0.05 and 0.55 per 10,000 treatments [30]. The most common serious adverse event is pneumothorax, followed by central nervous system injury and transmission of blood born infection. Serious adverse events are regrettably often associated with negligence and therapists not following standards of practice [34].

In terms of pneumothorax in particular most cases are unilateral and patients usually recover with conservative management [32, 35]. Saying this, there have been documented cases of bilateral pneumothoraxes and some cases of death as a result [36, 37]. For this reason, only one side of the thorax should be needled during any one treatment session [23]. The risk of inadvertent pneumothorax is increased when needling the thoracic area, especially in patients with slight frames or osteoporotic bone make up. A recent case study highlighted the risks of pneumothorax when dry needling the thoracic area [33], the video demonstration attached to the study is essential viewing for any physiotherapist who practices dry needling to the thoracic area.

Physiotherapist need to be aware of the signs and symptoms of pneumothorax. A non-exhaustive list includes chest pain which is often pleuritic, shortness of breath, decreased breath sounds, tachycardia and tachypnoea. The danger is that symptoms can often occur or become significant hours or days following the treatment [32, 33]. It is therefore essential that all patients are counselled regarding possible symptoms and the need to seek urgent medical attention if they become unwell following dry needling therapy. Especially in the thoracic area [23].

Contraindications to dry needling are logical considering the most common adverse events are bleeding, bruising, pain and cutaneous infections [7]. Absolute contraindications include anticoagulant therapy, bleeding disorder, skin infection, tumour, acutely unwell or lack of patient consent. All physiotherapists should be conscious of all contraindications to ensure patient safety is prioritised. Verbal consent should be obtained from the patient prior to performing any dry needling therapy. In some high risk cases this should be expanded to written consent. It would of course be standard practice during the consent process that the physiotherapist should ensure the patient has no contraindications to treatment and the patient should have an adequate understanding of any possible adverse events prior to agreeing to the dry needling therapy.

In conclusion, dry needling is a becoming an increasingly popular adjunct to physiotherapy. It is an invasive procedure which has been shown to provide good analgesic effect in the short to moderate term compared to no therapy [3–5]. There remains insufficient evidence to determine its benefit to patients in the long term or when compared to other adjunctive therapies [5, 18]. The common practice of ensuring a local twitch response is elicited is based on limited evidence [20, 24].

Mild adverse events are relatively common, with bleeding, bruising and pain being the most regularly reported [7]. Serious adverse events such as pneumothorax and neurological injuries are thankfully rare [30], especially when practice guidelines are followed appropriately. Guidelines for dry needling emphasise that the therapy should only be used when indicated, as an adjunct to regular physiotherapy. Essential anatomical and practical knowledge is needed to avoid adverse events [23, 38]. Contraindications to therapy should be actively sought and verbal consent should be obtained.

Dry needling has many potential benefits, but while the evidence for its appropriate treatment niche remains unclear it is important our main focus is patient safety and doing no harm.