Effectiveness of physiotherapy in carpal tunnel syndrome (CTS)

Carpal Tunnel Syndrome (CTS) is the most common peripheral neuropathy in the upper limb, occurring in 3-4% of the human population [1]. CTS most often occurs between 40-60 years of age and affects ten times more often women than men [2].

The median nerve extends in the wrist canal along the tendons of the front forearm muscle group. The wrist canal is limited by: bumps of the trapezium and scaphoid bones on the radial side and the pisiform and hamate bones on the ulnar side. Between them on the ventral side, the transverse wrist ligament is spread, commonly referred to as the flexor retinaculum [3]. CTS affects the median nerve by adjacent tissues, which in turn reduces its mobility in the canal [4–6]. Compression and reduction of lateral and longitudinal sliding of the mdian nerve is a direct cause of hand discomfort [7–9].

The etiology of carpal tunnel syndrome is not entirely clear. Usually, CTS arises due to the aggregation of several predisposing factors [1, 10]. These include: prolonged wrist overload, injuries, age, obesity, childbirth, acromegaly, kidney and thyroid diseases, diabetes and osteoarthritis [11,12]. The origins of CTS are mainly related to dysfunction of the median nerve sensory fibers. Most patients also have hand manipulation problems with properly preserved muscle strength. Impaired reception of sensory information of deep sensation causes a reduction in the precision of hand movements and pincer grip. As a result, patients involuntarily generate greater pinch force than is necessary to perform particular activity [13].

Symptoms of carpal tunnel appear in both or in one, dominant hand. These include: parasthesia, stinging, feeling of pain, numbness and weakening of the muscular strength of the hand, especially on the side of the first three fingers [2]. There is also a deterioration of the median nerve conduction [1]. CTS-related symptoms can also coexist within the arm and shoulder [14, 15]. Their significant intensity occurs at night.

Diagnosis of carpal tunnel syndrome includes the history of the disease, clinical symptoms, changes in the anthropometric dimensions of the hand and physical examination of the patient [8,16]. The final CTS verification is possible thanks to electrodiagnostic and imaging methods [1,11,12]. In differential diagnosis of CTS, should be excluded: damage to the spinal cord or brachial plexus, thoracic outlet syndrome(TOS), median nerve compression in the proximal part of the upper limb or in the reentrant muscle, degenerative changes [17,18,19]. For CTS diagnostics, the Boston Questionnaire (BCTQ - Boston Carpal Tunnel Questionarie) is also used. It consists of two parts. The first concerns the severity of the patient’s symptoms (SSS). The second one, examines the functional state of the hand and the level of its dysfunction (FSS) [20–22]

Research in the field of electrodiagnosis enables the elimination of polyneuropathy, radiculopathy and other disorders related to the median nerve [23]. Electroneurography (ENG) is a routine procedure performed in the diagnosis of carpal tunnel syndrome [24]. It is a study of nerve conduction, where the most important are: potential peak amplitude and sensory transmission speed of nerve fibers [25,26]. In the majority of cases, the ENG examination of the median nerve shows the extension of the final sensory and motor latency, the release of the conduction velocity in the sensory and motor fibers as well as the reduction of the sensory and motor potential amplitude. On the other hand, EMG allows to evaluate muscle stimulation [27]. Electromyography is helpful because it allows to localize pathological changes in the muscles, shows their size, character and determines the dynamics of the disease process [23,28]. This assessment is carried out on muscle groups innervated by the median nerve. Typically, CTS accompanies a significant reduction in muscle performance and strength, which leads to strength disbalance within the hand [25,29].

Ultrasonography (USG) and magnetic resonance imaging (MRI) are characterized by a lower degree of sensitivity compared to ENG. However, ultrasound is the cheapest and the fastest diagnostic method of CTS. It is worth noting that, the above studies allow to find additional factors and changes within the wrist [6,26,30]. They enable the diagnosis of tendon sheathitis, ganglia, degenerative changes of the bones and necrosis of blood vessels. It is also worth mentioning that, the result of USG or MRI examination may change the concept of the course of surgery, consequently reducing its postoperative effects. Due to economic reasons and the availability of cheaper methods, magnetic resonance is rarely used in the diagnosis of CTS [24].

Neurodynamic tests are used in patients with suspected neuropathy of incarceration. These include the Phalen and Tinnel test [31]. They are used to stretch nerves in patients with radiation to the upper extremity. Using stretch tests, we check whether the symptoms are similar to those described by the patient. Stretching mobilization involves the internal and external movement of the nerve with the casing and soft tissues. Sliding mobilization consists in the movement of the axon itself relative to the casing. The authors demonstrate the effectiveness of neurodynamic tests only in 46% of patients with CTS [32].

Physiotherapeutic interventions in the carpal tunnel syndrome focus on decompression of the median nerve within the wrist canal [33]. Conventional medical procedures are: relieving and immobilizing the upper limb, oral pharmacology and steroid injections. CTS rehabilitation includes treatments in the field of physical therapy, for example laser therapy or manual therapy in combination with neurodynamic techniques, functional massage [7, 34]. Alternative treatments for carpal tunnel syndrome include: acupuncture, yoga, massages, including the Chinese cupping massage. [7,35]. The effectiveness of conventional physiotherapeutic methods, for example laser therapy in relieving ailments, is temporary [14]. In a slightly newer approach, bioptron, shock wave, diathermy, insulin injection and progesterone are used, but their effectiveness is still the subject of debate. In the treatment of CTS, medicine turns to non-invasive activities in the field of manual therapy, neuromobilization and soft tissue techniques. These effects are very effective in the treatment of signs and symptoms of CTS [36–38].

The aim of this study was to review the literature and analyze the results of the latest research presenting modern methods and physiotherapeutic interventions and their effectiveness in inoperable treatment of patients with carpal tunnel syndrome (CTS).

The main criterion for the selection of articles for the review work was the purpose of the research carried out in them and the method of carpal tunnel syndrome diagnosis. The characteristics and size of the research and control groups of the analyzed works are presented in table 1 (Tab. 1).

The most important aspect of the analysis of the above articles was the type of physiotherapy intervention applied, its frequency and duration, as well as the conclusions formulated by the authors. Physiotherapeutic interventions consisted mainly of neuromobilization, manual therapy, fascial manipulation and other physical therapy. The results of the above analysis are presented in table 2 (Tab. 2).

The authors assessed the effectiveness of manual therapy in four works. An example of the applied physiotherapeutic intervention in the field of manual therapy according to Cyriax in the carpal tunnel syndrome is shown in Figure 1 (Fig. 1).

Fig. 1.

Cyriax manual therapy techniques used in CTS therapy [37].

Neuromobilization was used to treat carpal tunnel syndrome in three publications. The most reliable was its effectiveness in the study, in which it was compared with placebo techniques. An example of the applied physiotherapeutic intervention in the field of neuromobilization in the carpal tunnel syndrome is shown in Figure 2 (Fig. 2).

Fig. 2.

Neuromobilization used in the treatment of CTS [5].

The effectiveness of fascial manipulation and soft tissue therapy in the treatment of carpal tunnel syndrome was assessed in two works. One publication also tested kinesiotaping. The application according to the kinesiotaping method in the treatment of CTS is shown in Figure 3 (Fig. 3).

Fig. 3.

Application according to the kinesiotaping method used in the treatment of CTS [39].

In addition, the authors compared the effectiveness of the above procedure with standard physiotherapeutic treatment and immobilization in four articles.

Only three publications had a proper control groups. They introduced only one tested factor that allowed to distinguish the research group from the control group. This made it possible to form unambiguous conclusions regarding the effectiveness of the physiotherapy intervention examined. The authors of two publications created two groups in which they compared the effectiveness of completely different therapies, neuromobilization and other physical therapy intervention.

Not all publications accurately describe and clearly present the tested physiotherapeutic interventions. It is worth noting that, in the articles testing the effectiveness of physical therapy, the authors in a very accurate and precise manner showed all the parameters of the treatments examined.

The duration and frequency of physiotherapy interventions in the above publications varied. Their length ranged from 3 to 10 weeks. The time of the treatments was also varied, as in various authors it lasted from 10 to 45 minutes. The frequency of therapy was also different. In some studies, the therapy was carried out once a week, in others up to three times.

In one study, changes in the size of the wrist canal were evaluated during manual therapy of the wrist bone under ultrasound guidance. The process of the study is shown in figure 4 (Fig. 4).

Fig. 4.

Examination’s position testing changes in the dimensions of the wrist canal during the use of manual therapy techniques [3].

The authors decided to assess the effectiveness of physiotherapeutic interventions in the long-term dimension only in two publications. They made a reassessment of the effectiveness of the therapy few weeks after its completion.

Ellis et al. analyzed retrospectively 10 publications of the carpal tunnel syndrome. Their goal was to verify if there is a relationship between decreased nerve mobility in the wrist canal and the onset of CTS. The authors of all the studies reviewed above suggested that the study participants had a reduction in the longitudinal and transverse range of the median nerve (mobility). The mechanism of limiting his mobility begins under the flexor’s retinaculum, where is not only pressure on the median nerve, but also on venous and arterial vessels. This compression contributes to the formation of edema and consequently scar tissue, which reduces the mutual mobility of neighboring tissues. A similar situation occurs in the inflamed tendons of the flexor muscles of the fingers. As a consequence, the median nerve sticks to the surrounding tissues and even to the transverse ligament of the wrist. Statistically higher nerve mobility was observed in patients after treatment compared to those in the control group (oblong p <0.001, transverse p <0.05). On this basis, the authors concluded that the consequence of reducing the mobility of the median nerve within the wrist canal is CTS [1]. This study justifies the need for median neuromobilization in the treatment of carpal tunnel syndrome.

Bueno-Gracia et al. decided to assess whether the techniques in the field of manual therapy affect the change in the values of hand and wrist channel parameters. With the applied ultrasound probe at the level of the wrist, they assessed the impact of wrist bones mobilization on particular parameters. Their work shows that during the manual therapy there is a statistically significant increase in the wrist cross-sectional area (CSA) and an increase in the anterior-posterior diameter (ADP) ofs] the wrist canal [3]. The above study proves the need for manual wrist bones therapy in the treatment of carpal tunnel syndrome as it causes decompression of the median nerve.

In the majority of studies, the patients’qualification was based on the most effective diagnostic methods of carpal tunnel syndrome (CTS): USG and ENG [37]. Studies have reported that some people have other conditions that give similar symptoms to CTS, such as cervical reticulopathy, thoracic outlet syndrome (TOS) or proximal median nerve incarceration. [11,12,15,17]. It follows that reliable and unambiguous diagnosis of CTS minimizes the risk of unnecessary physiotherapeutic and surgical interventions [24,26].

Almost in all studies, the BCTQ questionnaire was used to verify the effectiveness of individual therapies. It allowed to evaluate the effectiveness of the therapy in terms of functional (FSS) and symptomatic (SSS). The Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) is an important and reliable clinical tool in the diagnosis of CTS. It consists of two parts: Symptom Severity Scale (SSS) and Functional Status Scale (FSS). The first one (SSS) is built of 11 questions and creates a 5-point scale to assess the severity of symptoms from the CTS. The FSS consists of eight elements estimating the degree of hand functionality. Assessment of the patient according to SSS and FSS gives a final score showing the severity of the carpal tunnel syndrome. [20,39].

Leit et al. decided to assess the effectiveness and credibility of the BCTQ questionnaire. The authors systematically reviewed studies on the psychometric properties of BCTQ to determine its level of diagnostic reliability. An important aspect of the above studies was the inclusion of the patient’s condition with CTS from his perspective. The authors analyzed 10 studies to verify the structure of the content, relevance and reliability of the questionnaire. Statistical analysis was performed comparing SSS and FSS with other CTS diagnostic tools, including DASH questionnaire (Disabilities of the Arm, Shoulder and Hand Questionnaire). Based on the data analysis, the authors concluded that BCTQ is a valuable and reliable tool that should be used as a basic measurement instrument in future studies of carpal tunnel syndrome [20]. Virtually all tested interventions in the field of manual therapy, neuromobilization, osteopathy, fascial manipulation and other kinds od physiotherapy have resulted in improved results in BCTQ [20]. In many cases, despite the absence of changes before and after the therapy cycle, the improvement was recorded in the BCTQ parameters. This indicates that patients improved despite the lack of changes in ENG or USG [5,37,38].

Wolny et al. showed how he created a placebo group and what techniques used in this group differ from the true neuromobilization’s techniques of the median nerve [5]. It is also important to provide the exact parameters of the treatments being tested in the field of physical therapy [7,14,38]. Just like the detailed description and insertion of images of the tape application in the kinesiotaping, it concretizes which application was tested [39]. This allowed for a thorough interpretation and understanding of the research published by the authors.

In several of the above publications, the authors compared the effectiveness of two, absolutely different treatments [7,14]. They have proven that routine physiotherapy is often less effective than newer interventions. Others, in turn, created two groups, the research and the control group, which were differed in one parameter tested by the authors [36,38,39]. It should be noted that these tests actually show whether there is a significant difference between the groups and whether the tested therapeutic agent allows to achieve a higher therapeutic effect in patients with CTS.

It is worth mentioning that only in the articles of Pratelli et al. and Mordalii Bongi et al. evaluated the condition of patients several weeks after completion of therapeutic procedures. They were able to confirm that treatments in the field of manual therapy and fascial manipulation demonstrate long-term effectiveness, and the health effects achieved last long [14,37]. Pratelli et al. in his work also showed that in the case of laser therapy (LLLT), after 3 months from the end of the intervention, the obtained therapeutic effect was withdrawn [14]. The above long-term efficacy parameter should be included in all physiotherapeutic studies because it allows for additional conclusions regarding the effectiveness of rehabilitation.

The above review presents a summary of the effectiveness of various types of physiotherapeutic interventions in the conservative treatment of carpal tunnel syndrome (CTS). On their basis, significant benefits and improvement of CTS symptoms are visible. Some authors compared the effectiveness of two different physiotherapeutic interventions in the treatment of carpal tunnel syndrome. Not all studies contained control groups that enable accurate and reliable comparison of the effects of the tested therapies. Some of the studies had very small research and control groups, which indirectly affects the reliability of these tests. Only in two articles was the effectiveness of therapeutic intervention checked a few weeks after its completion, which allowed to formulate broader conclusions on the effectiveness of the physiotherapy methods studied.

The development of physiotherapy and research on therapies in the carpal tunnel syndrome (CTS) allows physiotherapists to do more effective CTS treatment, they give physicians a wider range of methods to help patients with CTS. This increases the chances of avoiding or delaying surgical intervention.