Chapter 8

Deep Dry Needling of the Shoulder Muscles

Carel Bron; Jo L.M. Franssen; Betty T.M. Beersma; Jan Dommerholt

Introduction

Shoulder pain, shoulder complaints, and shoulder disorders are common terms that frequently are used interchangeably as there is some overlap between these concepts. In this chapter we will use the term shoulder pain, which is a very common musculoskeletal disorder. In primary care the yearly incidence of shoulder pain is estimated to be 14.2 per 1000 people. The 1-year prevalence in the general population is estimated to be 20% to 50%. The estimates are strongly influenced by the definition of shoulder disorders, as well as by inclusion and exclusion criteria such as limited motion, age, gender, and anatomical areas. Thus shoulder pain is widespread and imposes a considerable burden on the affected person and on society. Women are slightly more affected than men, and the frequency of shoulder pain peaks between 46 and 64 years of age (van der Windt et al., 1995). Shoulder pain tends to be persistent or recurrent despite medical treatment (Ginn & Cohen, 2004). The pathophysiological mechanisms are poorly understood, in spite of a growing body of knowledge of shoulder kinematics, injury mechanisms, and the technical advances of medical imaging, including sonography, magnetic resonance imaging, and more conventional techniques such as x-rays.

Most shoulder pains are caused by a small number of relatively common conditions. Although subacromial impingement is often suggested to be the most common potential source of shoulder pain (Neer, 1972; Hawkins & Hobeika, 1983), solid evidence is lacking (Bron, 2008). Moreover, in 2011 Papadonikolakis and colleagues (2011) reported in a systematic review that there was no published evidence to support the diagnosis of subacromial impingement. This syndrome includes tendonitis or tendinopathy of the rotator cuff and the long head of the biceps brachii muscle, or subacromial or subdeltoid bursitis. In fact, calcifications, acromion spurs, subacromial fluid, or signs of tendon degeneration are equally prevalent in healthy subjects and in individuals with shoulder pain (Milgrom et al., 1995). Furthermore, physical examination tests of subacromial impingement are not reliable (Hegedus et al., 2008), and the results of imaging diagnostics do not correlate well with pain (Bradley et al., 2005). In addition, interventions targeting subacromial problems are, at best, only moderately effective at treating patients with shoulder complaints (Coghlan et al., 2008; Buchbinder et al., 2009; Dorrestijn et al., 2009). Other less common causes of shoulder pain are tumours, infections, and nerve-related injuries.

Histological studies have determined that the rotator cuff is made of multiple confluent tissue layers functioning in concert. The tendons of the supraspinatus and the infraspinatus merge together at the level of the greater tuberosity, whereas the infraspinatus and teres minor merge near their musculotendinous junctions. The subscapularis tendon and the supraspinatus tendon join as a sheath around the biceps tendon at the entrance of the bicipital groove (Matava et al., 2005).

Clinical relevance of myofascial trigger points in shoulder pain syndromes

Myofascial trigger points (TrPs) in patients with shoulder pain are most prevalent in the infraspinatus, upper trapezius, and deltoid muscles; most of the time, multiple TrPs in more than one muscle are involved. Ingber (2000) successfully treated the subscapularis muscle, which he considered to be the main cause of shoulder pain in three overhead athletes. Hidalgo-Lozano and colleagues (2010) found that the muscles most affected by active TrPs were the supraspinatus, infraspinatus, and subscapularis in patients with shoulder pain with a medical diagnosis of shoulder impingement. Elite swimmers with shoulder pain presented with similar findings (Hidalgo-Lozano et al., 2013).

In an older study, Sola and Kuitert (1955) concluded that the supraspinatus muscle was one of the least frequently involved shoulder girdle muscles, both in patients and in young healthy adults. The supraspinatus muscle is rarely involved by itself but usually appears in association with the infraspinatus or upper trapezius muscles (Bron et al., 2011b) or the subscapularis muscle (Hidalgo-Lozano et al., 2010), which very commonly harbor TrPs in patients with shoulder pain and dysfunction. In addition, other muscles such as the levator scapulae, biceps brachii, deltoid, pectoralis minor, pectoralis major, scalene, latissimus dorsi, and teres major and minor muscles may also be involved in shoulder pain. Additionally, it should be mentioned that not only are multiple muscles involved in patients with shoulder pain, but that each and every muscle can harbor multiple TrPs, both active and latent (Ge et al., 2008). In fact, two studies demonstrated that TrPs in the latissimus dorsi and pectoralis major muscles reproduced axillary arm pain in women with breast cancer who had undergone mastectomies (Fernandez-Lao et al., 2010).

Two randomised controlled trials showed promising results of manual TrP therapy in patients with shoulder pain (Hains et al., 2010; Bron et al., 2011a). Furthermore, an increasing number of studies report the effects of dry needling (DN) on pain and function with varying results. Arias-Buria and colleagues (2017) found that the inclusion of two sessions of TrP DN had significant positive effects on function but not on pain, which lasted for at least 12 months. In another study, patients aged 65 years and older were needled once in the infraspinatus muscle. Needling of an active TrP with or without needling of a latent TrP in the infraspinatus muscle had a significant effect on pain, pressure pain thresholds, and grip strength. Unfortunately, no comparison is made with a control group that received no treatment or sham treatment (Calvo-Lobo et al., 2017). In a study comparing a single session of DN of the infraspinatus on the symptomatic shoulder with the asymptomatic shoulder, researchers found that pain sensitivity and range of motion (ROM) increased after 3 to 4 days posttreatment in the symptomatic shoulder, whereas the muscle function was unchanged (Koppenhaver et al., 2016). Lane and colleagues (2017) described a case report of a 60-year-old woman with complaints of shoulder pain and upper extremity numbness and tingling elicited by compression of TrPs in the infraspinatus and teres minor muscles; DN resolved her symptoms in just two sessions.

Even patients suffering from spasticity after stroke may benefit from DN of shoulder muscles (Mendigutia-Gomez et al., 2016) as discussed in detail in Chapter 4. One study investigated the effects of TrP DN in patients with poststroke shoulder pain and reported that patients in the intervention group reduced their analgesic medication use, improved their sleep and mood, and more effectively prepared them for their rehabilitation program than those in the control group (DiLorenzo et al., 2004). Others concluded that DN was not a valuable adjunct to an individual physical therapy protocol in the treatment of shoulder pain (Perez-Palomares et al., 2017). Finally, a research group from Taiwan reported that one single session of DN of myofascial TrPs in the extensor group of the forearm had an immediate small but significant effect on pain and pressure pain threshold in the ipsilateral trapezius muscle with an increase of the cervical ROM in contralateral sidebending (Tsai et al., 2010).

Shoulder Pain and Movement Dysfunction

Shoulder pain and disturbed movement patterns are closely related. A disturbed movement pattern of the scapular musculature such as the upper or lower trapezius and the anterior serratus muscles may cause mechanical dysfunction and deep shoulder pain (Cools et al., 2003; Kibler, 2006). On the other hand, there is evidence that muscle pain can create a different motor activation pattern. Falla and colleagues (2007) demonstrated that an injection with hypertonic saline reduced the electromyographic (EMG) activity in the painful (injected) muscle and led to hyperactivity of the muscles in the ipsilateral and contralateral shoulder. Another study found that latent TrPs in the posterior deltoid muscles were associated with reduced efficiency of reciprocal inhibition, which may lead to unbalanced muscle activation (Ibarra et al., 2011).

These findings appear consistent with the pain adaptation model of Lund and colleagues (1991), which maintains that muscle pain causes a decrease of EMG activity in the agonist muscle but causes an increase of EMG activity in the antagonists, finally leading to motor control changes. Martin and colleagues (2008) showed, however, that muscle nociception may result in excitation of both elbow flexor and extensor muscles; other researchers noted that the activity of motor neurons is not necessarily uniformly decreased (Farina et al., 2004, 2005; Tucker et al., 2009). As active TrPs cause muscle pain, they may also cause muscle inhibition and disturbances of motor activation patterns. In fact several researchers demonstrated that latent TrPs can disturb motor activation patterns (Lucas et al., 2010; Ibarra et al., 2011; Bohlooli et al., 2016).

Trigger Points and Range of Motion Restrictions

Adhesive capsulitis, also referred to as primary frozen shoulder, is the most common cause of severely restricted shoulder joint mobility. Of interest is that thickening of the shoulder capsule was identified as a primary shoulder motion restriction independent of adhesions (Texeira et al., 2012). Although the natural history of a frozen shoulder is usually described as consisting of episodes with stiffness and recovery phases eventually progressing to full recovery, there is no scientific evidence in support of this notion (Wong et al., 2017). Based on clinical experience of the authors of this chapter, inactivation of TrP in shoulder muscles, particularly the subscapularis muscle, frequently reduces patients’ symptoms—including pain and restricted mobility—which may lead to an early and proper recovery within weeks. Again, there is no scientific evidence from the literature to support this clinical experience. In a multiple case study of five patients with primary frozen shoulders, all patients improved after a subscapular nerve block and subscapularis muscle injections (Jankovic & van Zundert, 2006). Recently another case report described the clinical reasoning behind the use of TrP DN in the treatment of a patient with adhesive capsulitis in which the rapid improvement seen after DN may suggest that muscles may indeed be a significant source of pain in this condition (Clewley et al., 2014).

Trigger Points and Stability

Another enigmatic shoulder disorder is referred to as minor, subtle, occult, or functional instability, which is often associated with shoulder pain and diagnosed as secondary shoulder impingement. Patients with this disorder complain of a feeling of instability in the absence of true instability, confirmed by physical examination tests such as the apprehension test. Although not mentioned in the literature, these patients often respond well to DN of the adductor muscles of the shoulder, including the teres major, latissimus dorsi, and subscapularis muscles. Unfortunately, until now there are no studies that have reported the clinical effects of DN on subtle shoulder instability, although the study by Ibarra and colleagues (2011) found evidence of fine movement control disturbances due to shoulder muscle TrPs.

Dry needling of the shoulder muscles

Some of the shoulder muscles are covered in other chapters. The coracobrachialis, bíceps, and triceps muscles are described in Chapter 9; the rhomboid and latissimus dorsi muscles are included in Chapter 10.

Supraspinatus Muscle

• Anatomy: The supraspinatus muscle originates from the supraspinous fossa of the scapula and inserts at the superior facet of the greater tubercle of the humerus.
• Function: The supraspinatus muscle assists in abduction and stabilises the humeral head together with the other rotator cuff muscles during all movements of the shoulder. The muscle prevents caudal dislocation during carrying of heavy loads such as bags and suitcases.
• Innervation: Suprascapular nerve, from the C5 and C6 nerve roots.
• Referred pain: TrP may refer to the middeltoid region, often extending down the lateral aspect of the arm and forearm, sometimes focusing strongly over the lateral epicondyle of the elbow.
• Needling technique: The patient lies prone (Fig. 8.1) or on the uninvolved side with the arm close to the body and relaxed (in sidelying position supported by a pillow) (Fig. 8.2). The supraspinatus muscle is only accessible through the upper trapezius muscle and is identified by flat palpation with sufficient pressure. After localisation of the TrP, the needle is inserted and directed longitudinal to the frontal plane or slightly posterior towards the base of the supraspinous fossa.

Fig. 8.1 Dry needling of the supraspinatus muscle in prone position.

Fig. 8.2 Dry needling of the supraspinatus muscle in sidelying position.

• Precautions: The apex of the lung is in front of the scapula, and clinicians should avoid needling in a ventral direction.

Infraspinatus Muscle

• Anatomy: The infraspinatus muscle originates from the infraspinous fossa of the scapula and inserts at the dorsosuperior facet of the greater tubercle of the humerus.
• Function: The infraspinatus muscle assists in external rotation and stabilises the humeral head together with the other rotator cuff muscles and prevents upwards migration of the humeral head during all movements.
• Innervation: Suprascapular nerve, from the C5 and C6 nerve roots.
• Referred pain: TrP may refer to the front of the shoulder (intraarticular pain) and the middeltiod region, extending downwards the arm to the ventrolateral aspect of the arm and forearm and the radial aspect of the hand. The referred pain from this muscle can mimic the symptoms of carpal tunnel syndrome (Qerama et al., 2009).
• Needling technique: The patient lies prone (Fig. 8.3) or on the uninvolved side with the arm supported by a pillow (Fig. 8.4). The needle is directed towards the scapula.