Effectiveness of Tendon and Nerve Gliding Exercises in the Treatment of Patients With Mild Idiopathic Carpal Tunnel Syndrome: A Randomized Controlled Trial

Abstract

Background

There is limited evidence regarding the efficacy of different treatment options in patients with carpal tunnel syndrome (CTS). This study aimed at assessing the effectiveness of nerve and tendon gliding exercises in the treatment of patients with mild CTS.

Methods

The current prospective, randomized trial with pretest-posttest design was conducted on 80 patients with mild CTS randomly assigned to 2 groups. The treatment group was instructed to perform gliding exercises in addition to the wrist splint use. The control group only used the wrist splint. All the patients were instructed to use the splint at night and during the day if required. Patients were evaluated in terms of clinical parameters (ie, grip and pinch strength). The severity of symptoms and functional status was also determined using the Boston Carpal Tunnel Syndrome Questionnaire. The subjects were followed up for 6 weeks.

Results

There were no significant differences in all parameters between groups. The pretest-posttest analysis showed a statistically significant improvement in subjective and objective parameters in the treatment group. However, in the control group, only a significant improvement was observed in grip strength. Wrist splint use led to a significant change in the severity of symptoms only over the second week.

Conclusions

Both gliding exercise and wrist splint groups showed some improvement in the severity of symptoms and functional status scores. However, the gliding exercises did not offer additional benefit compared with wrist splint alone.

Introduction

Carpal tunnel syndrome (CTS) is the most common neuropathy caused by compression and tension of the median nerve at the carpal tunnel of the wrist. ¹ The prevalence of CTS varies in different populations.^2,3 Studies show that it has different etiologies and is more common in women than in men.^1,4 Every condition that decreases the size of the tunnel or causes swelling in the inside structures may lead to the compression of the median nerve. Carpal tunnel syndrome is diagnosed based on clinical signs and symptoms, and ultimately electrodiagnostic testing. ⁵ The most common symptoms of CTS are pain and paresthesia (pins and needles) with or without numbness in the median nerve area of the wrist. ³ Treatment of CTS is based on eliminating the pressure on the median nerve.

Although different surgical and nonoperative procedures are used in treating CTS, evidence for the efficacy of treatment options is limited.^6-8 The advantage of nonoperative treatment, in comparison with surgical therapies, is that there are no consequences such as painful scars, postoperative complications, and delay in rehabilitation. ⁹ Several nonoperative therapies are used to reduce the symptoms of idiopathic CTS. Wrist splinting is a method widely used in treating patients. These splints hold the wrist in a neutral and nonbending position, and thus the lowest amount of pressure is applied to the median nerve. Although the best time to use the wrist splint is not specified, it is often recommended to use it during the night or in daytime in case of repetitive wrist movements. ¹⁰ Exercise therapy is one of the newest methods to control CTS symptoms. Reduced nerve gliding was observed in the respective channel in patients with CTS, ¹¹ and exercise provides conditions for flexibility and the enhancement of the nerve gliding. Flicking fingers, even when hands are motionless, creates the proper movement of the median nerve and the flexing tendon along the wrist, which prevents adhesion. ¹² The alternating flexion-extension exercises of the wrist and fingers actually cause stretching of the carpal tunnel connections, widening the longitudinal area of the connection between the nerve and transverse carpal ligament, reducing the tenosynovial swelling, improving the venous return from the nerve nodes, and reducing the pressure within the carpal tunnel.^6,13 Although many studies are conducted on the effects of conservative treatments on patients with CTS, their results are controversial, and further studies in this area seem necessary. Based on a recent systematic review, tendon and nerve gliding exercises, when combined with conventional treatments, may have a favorable effect on patients with CTS. ⁶

Therefore, the current clinical trial aimed at assessing the effectiveness of nerve and tendon gliding exercises in the treatment of patients with mild idiopathic CTS.

Materials and Method

Study Population

In this clinical trial, all patients with clinically suspected CTS referred to the surgery and sports medicine clinic were assessed for eligibility. The study was performed from January 2017 to February 2019 at Sina Hospital, Tehran, Iran. Inclusion criteria were: age >18 years, reporting of symptoms of CTS (pain, paresthesia in the area of hand innervated by the median nerve), and electrophysiological findings of nerve compression (mild CTS). Exclusion criteria were: previous treatment with splint or surgery; history of any trauma on the hands, neck, and shoulders within 3 months of the study onset; history of wrist surgery; history of pregnancy; diabetes; thyroid disorders; and any findings suggesting conditions that interfere with CTS (eg, cervical radiculopathy). Informed consent was obtained from all patients for being included in the study. All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation of Tehran University of Medical Sciences, Tehran, Iran, and with the Helsinki Declaration.

Protocol

Patients were selected based on medical history, physical examination results, and electrophysiological findings. In this study, a hand surgeon confirmed inclusion/exclusion criteria and completed neurologic examinations. A surgeon assistant obtained informed consents, collected self-report questionnaires, and conducted treatment allocations. A sports medicine specialist also visited the patients to complete special CTS examination, train the exercise protocol, and follow up their compliance with the intervention. In the first visit, all the patients completed the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ). A log book containing detailed explanation of prescribed exercises and a self-report daily exercise checklist were given to participants. Subjects were free to withdraw from the study at any time during the follow-up period. Follow-up examinations were scheduled at 2- and 6-week intervals after the intervention.

Blinding

Except sports medicine specialist who educated patients for correct exercising, other researchers were blind to the allocated treatments.

Treatment Allocation

Patients were randomly allocated to receive either splinting or splinting with exercise (Figure 1). A researcher (M.KH) not involved in the selection and treatment of patients prepared and sealed opaque envelopes containing the treatment options. Every patient randomly chose 1 sealed opaque envelope to determine the type of intervention. If bilateral symptoms were present, the hand with the more severe symptoms (according to the patient) was treated.

Figure 1.

The study flowchart.

Treatment

After assigning patients to specific groups, prefabricated splints (wrist and forearm splint; Tynor, India) were given to both groups, and the subjects were asked to use it for 6 weeks. In these splints, the wrist was held in a neutral position, and the fingers were free. The subjects were urged to wear the splint during the night or in daytime in case of repetitive wrist movements. The patients in the treatment group were prescribed a tendon and nerve gliding exercise program developed by Totten and Hunter. ¹⁴ In tendon glide exercises, fingers are held in 5 positions of straight, hook, fist, tabletop, and long fist, respectively (Figure 2). The fingers are in full extension between these positions. At all stages of this exercise, the wrist is in a neutral position. By doing the nerve glide exercises, the median nerve moves through the wrist and the fingers in 6 different positions. To do this exercise, the elbows are kept supinated with 90° of flexion, and the shoulder and neck are in the neutral position. In the first state, the wrist is in a neutral position, and the fingers and thumb are in flexion. In the second state, the wrist is in a neutral position, and the fingers and thumb are in extension. In the third state, the wrist and fingers are in extension, and the thumb is in a neutral position. Then, the wrist, fingers, and thumb are held in the extension position. In the next step, maintaining the previous position, the forearm is kept supinated. In the final step, a mild extension is applied to the exercising thumb by the opposite hand (Figure 3). Patients were asked to perform all the exercises 3 times a day, 10 repeats each time, and hold each position for 5 seconds. The exercise therapy lasted for 6 weeks. During the treatment, patients were asked to confirm daily exercise in the checklist tailored for this purpose. After the treatment, the patients were revisited, and the tests performed at baseline were repeated for them.

Figure 2.

Tendon gliding exercises. In tendon gliding exercises, fingers are held in 5 positions of (a) straight, (b) hook, (c) fist, (d) tabletop, and (e) long fist.

Figure 3.

Nerve gliding exercises.

Note. (a) Wrist in a neutral position, and the fingers and thumb in flexion. (b) Wrist in a neutral position, and the fingers and thumb in extension. (c) Wrist and fingers in extension and the thumb in a neutral position. (d) Wrist, fingers, and thumb in extension. (e) Wrist, fingers, and thumb in extension and the forearm in supination. (f) Mild extension to the exercising thumb by the opposite hand.

Outcome Measures

Demographic information and medical history of the subjects were collected using a structured questionnaire. Severity of the symptoms was assessed by BCTQ. The secondary outcome measures were the grip and pinch strength assessed by dynamometer and pinch meter, respectively. Results of nerve conduction studies were used to confirm the severity of CTS.

The BCTQ is an instrument specifically developed for patients with CTS. ¹⁵ The symptom severity scale includes 11 items on pain, nighttime symptoms, numbness, paresthesia, and weakness, and the functional status scale evaluates 8 activities (ie, difficulty in writing, buttoning up the shirt, opening the can, holding a book, holding the phone, housework, carrying the vegetable bag, and bathing and dressing). The items are scored based on a 6-point Likert scale from 1 (no difficulty with activity) to 5 (cannot perform the activity at all).

Special Tests

After receiving the medical history, physical examination was performed using the Tinel sign and the Phalen maneuver, carpal compression, and 2-point discrimination tests. Sensitivity ranges from 42% to 85% for the Phalen test and from 38% to 100% for the Tinel test; specificity ranges from 54% to 98% and from 55% to 100%, respectively. ² To examine the Phalen sign, the patient flexes his wrist for 60 seconds; a positive Phalen sign is defined as paresthesia or numbness in the median nerve area during testing. To perform the Tinel test, the median nerve in the wrist is lightly tapped over, and if the patient experiences paresthesia in the median nerve pathway, the result is considered as positive. ¹⁶ The carpal compression test is to apply a direct pressure over the carpal tunnel and its contents, including the median nerve, for 30 seconds; if pins and needles are felt at the end of the fingers, the test result is considered as positive.^3,17 This test is more sensitive and more specific than the Tinel and the Phalen tests. ¹⁷ The 2-point discrimination was measured by the Jamar discriminator on the pulp of the 3 radial fingers, and the mean of the numbers was recorded. ¹⁸ The grip strength was measured by the Jamar handheld dynamometer. For this purpose, the patient sits comfortably, and while the shoulders are abducting, the elbow is bent by 90° and the forearm is placed in a neutral position. The patient’s wrist has an extension of 0° to 30° during grip measurement. In each handgrip, the strength was measured 3 times with 1-minute rest between, and then the mean values were recorded. ¹⁹ The pinch strength of the patients was measured by a pinch meter (Jamar) between the tip of the thumb and the second finger. The patient’s pinch was also measured 3 times in the same grip measurement state, and the mean of it was recorded. ²⁰ All measurements were performed by a sports medicine specialist.

Statistical Analysis

Statistical analysis was performed using SPSS software (V.22.0). Results of normally distributed continuous variables are expressed as mean ± SD; categorical data are expressed as percentages. The Shapiro-Wilk test was used to examine whether the variables were normally distributed. Groups data were compared using the Mann-Whitney U test. The Wilcoxon and McNemar tests were used to compare the parameters of the 2 groups before and after treatment. A value of P ≤ .05 was considered as the level of significance.

Results

In this study, 2 subjects withdrew: one of them had an injection and the other one was lost to follow-up (Figure 3). Thus, 80 subjects (13 men and 67 women) completed the study. The participants were divided into 2 groups. The treatment group included 42 (52.5%) participants performing exercises in addition to using splint, and the control group included 38 (47.5%) participants using only wrist splint. Among the participants, 49 (61.3%) and 31 (38.7%) were housewife and employee, respectively. Forty-five subjects reported bilateral CTS. Demographic characteristics and clinical features of both groups before the treatment are illustrated in Table 1. There was no significant difference between the groups in any of the parameters. Based on the given checklist, adherence to exercise protocol was 85%.

Table 1.

Demographics and Clinical Features of the Participants.

Variable	Treatment group n = 42	Control group n = 38	P value
Age, y	49.9 ± 8.92	49.5 ± 10.19	.85
Weight, kg	75.79 ± 14.37	73.63 ± 10.9	.45
BMI	28.26 ± 4.78	27.83 ± 3.69	.66
Working times per week, h	34.17 ± 12.66	39 ± 10.87	.07
Tinel sign, positive, No. (%)	6 (14)	3 (8)	.41
Phalen sign, positive, No. (%)	11 (26)	12 (31)	.62
Compression sign, positive, No. (%)	13 (31)	7 (18)	.30
Hand grip strength, kg	19.14 ± 7.96	19.33 ± 6.99	.91
Pinch strength, kg	13.01 ± 4.09	13.26 ± 4.14	.78
Two-point discrimination, mm	5.79 ± 0.87	5.66 ± 0.7	.47
Functional status score a	15.47 ± 7.29	13.84 ± 5.42	.41
Symptom severity score a	25.69 ± 10.92	22.57 ± 9.06	.20

Note. Data are expressed as mean ± SD or No. (%). BMI = body mass index.

^aHigher scores indicate greater impairment.

Examining the data obtained from questionnaires showed that the data were not normally distributed based on the results of the Kolmogorov-Smirnov and Shapiro-Wilk tests; therefore, nonparametric tests were used for analysis.

The results of comparison of the mean of all scores related to BCTQ showed no significant difference between the 2 groups in severity of the symptoms and the functional status in any of the intervals (Table 2). Comparison of the results of each group before and after the intervention showed a significant difference after 2 weeks in the severity of symptoms and function of patients in the treatment group (P < .001). This improvement was also observed on the sixth week (P < .001), whereas the control group showed only a significant improvement in the severity of the symptoms during the second to sixth week (P = .003) (Table 3).

Table 2.

Comparison of the Total Score of Boston Questionnaire at Different Time Intervals Between 2 Groups.

Time, wk	Severity of symptoms		P value	Functional status		P value
	Treatment group	Control group		Treatment group	Control group
0	25.6 ± 10.9	22.5 ± 9.0	.2	15.4 ± 7.2	13.8 ± 5.4	.4
2	21.8 ± 10.4	21.8 ± 9.6	.8	13.8 ± 7.2	13.7 ± 5.8	.4
6	16.9 ± 7.6	18.6 ± 6.9	.1	11.7 ± 5.1	12.2 ± 4.6	.1

Note. Data are expressed as mean ± SD.

Table 3.

Comparison of the Total Score of Boston Questionnaire at Different Time Intervals in Each Group.

Time, wk	Severity of symptoms		Functional status
	Treatment group	Control group	Treatment group	Control group
0	25.6 ± 10.9	22.5 ± 9.0	15.4 ± 7.2	13.8 ± 5.4
2	21.8 ± 10.4*	21.8 ± 9.6	13.8 ± 7.2*	13.7 ± 5.8*
6	16.9 ± 7.6 #	18.6 ± 6.9 #	11.7 ± 5.1 #	12.2 ± 4.6

Note. Data are expressed as mean ± SD.

^*P <.05 comparison of before treatment and second week.

^#P <.05 comparison of second week and sixth week.

There was no significant difference between the 2 groups regarding the severity of symptoms and functional status at baseline, as well as the second and sixth week. Except for the amount of weakness in the hand (P = .04) and one of the hand functions (buttoning up shirts) (P = .03), which were significantly higher in the treatment group than the control group, none of the variables related to the symptoms and function had a significant difference between the 2 groups.

At the examination performed 6 weeks after the treatment, there was no statistically significant improvement in all parameters in both groups, except for pinch and grip strength (Table 4). There was a statistically significant improvement in pinch and grip strength at all times of assessment in the treatment group. Grip strength in the treatment group improved from 19.14 to 22.47 kg (P < .001). Grip strength in the control group showed only improvement after 6 weeks from intervention onset (P = .005), but difference in pinch strength was not significant.

Table 4.

Comparison of Pinch and Grip Strength at Different Time Intervals in Each Group.

Time, wk	Pinch strength, kg				Grip strength, kg
	Treatment group	P value	Control group	P value	Treatment group	P value	Control group	P value
0	13.0 ± 4.0	<.001*	13.2 ± 4.1	.1	19.1 ± 7.9	<.001*	19.3 ± 6.9	.1
2	14.0 ± 4.4		13.7 ± 3.9		20.3 ± 7.8		19.7 ± 6.6
6	14.8 ± 4.4	<.001*	13.6 ± 3.9	.1	22.4 ± 7.8	.001*	21.3 ± 7.8	.005*

Note. Data are expressed as mean ± SD.

^*Statistical significance (P value) set at <.05.

Discussion

The main finding of the present randomized controlled trial was that both the treatment and control groups improved over time. However, there were no significant differences between the groups. Pinch and grip strength significantly improved in the treatment group from baseline to the 6-week follow-up. In the control group, pinch strength was greater over 2 weeks; however, the improvement was not sustained for the additional 4 weeks. Grip strength in the control group significantly improved at the end of follow-up. There was no difference in the results of the Tinel, Phalen, and compression tests after the treatment in the 2 groups.

Currently, several nonoperative interventions are used to treat CTS. However, there are doubts about which treatment is the most appropriate one. Despite the low level of evidence, the effectiveness of immobilization is somewhat ascertained, ¹² although there still exists scarcity of evidence about the effectiveness of exercise in CTS treatment. Some studies indicate limited evidence for the effectiveness of exercise therapy.^3,12,21

In a study similar to the current one, Akalin et al ²² assessed the effect of nerve and tendon gliding exercises on CTS. They reported that both groups had improvement in all parameters. Although the results were more satisfactory in the group that received exercise than the group that used only splint, the difference was not statistically significant except for the lateral pinch strength. In a similar study by Pinar et al, ¹³ a before and after intervention analysis showed improvement in all of the outcome measures in both groups. However, they found that the group in which nerve gliding exercises were added to conservative therapy approaches demonstrated more rapid pain reduction and greater functional improvement, especially in grip strength. Another investigation assessed the effectiveness of tendon and nerve gliding exercises as a part of combined treatment, separately. ²³ The authors reported that the combination of tendon gliding exercises with conventional treatments may be more effective than nerve gliding exercises. The result of another study ²⁴ showed that the combination of orthosis, nerve/tendon gliding exercises, and ultrasound therapy did not offer additional benefit compared with orthosis alone.

In the control group, the wrist splint significantly reduced symptoms over 2 weeks, and that improvement was sustained for an additional 4 weeks. Although this finding was consistent with those of other studies, in this study, wrist splint did not have any effect on functional status. A possible reason for the effectiveness of wrist splint is decreasing pressure in the carpal tunnel by holding the wrist firm in a neutral position. ¹² But in other groups receiving exercise in addition to wrist splint, either severity symptoms or functional status improved in 2 and 6 weeks. In the control group, grip strength showed improvement at the end of the sixth week. It was the time that severity of symptoms decreased. It can be concluded that decreased symptoms led to grip strength improvement. But in the treatment group, grip and pinch strength as well as symptoms and functional status improved in parallel and during the follow-up. Tendon gliding exercises involve a sequence of finger movements, and nerve gliding exercises include wrist and finger movements. Gliding exercises reduce pressure inside the carpal tunnel through decreasing adhesions around the tendons and median nerve, tenosynovial edema, direct mobilization of the nerve, improving the excursion of the nerve and tendons, and facilitating venous return; thus, these dynamic exercises would improve symptoms.^12,22,25 The pressure in the carpal tunnel is lowest in the neutral position; however, the pressure rises significantly as the wrist is moved into flexion or extension, ²⁵ but nerve and tendon gliding exercises with controlled active wrist and finger motions can reduce pressure in the canal.

The limitation of this study was the short-term follow-up. Outcome measures were assessed at 2 and 6 weeks. Thus, long-term results are unknown. However, this study had methodological strengths, including the randomized design, the use of valid and standard measures, and the evaluation of the functional status of patients.

In this study, exercise therapy was prescribed in association with splint use. Future research needs to be conducted to determine the effectiveness of these exercises as a single treatment with a longer follow-up to determine long-term effects of the intervention. It is also suggested that further studies be designed with a larger sample size and a more strenuous adherence to the exercise protocol.

Conclusion

According to the results of this study, both gliding exercise and wrist splint groups showed some improvement in symptom severity and functional status scores. However, the gliding exercises did not offer additional benefit compared with wrist splint alone.