Adding Extracorporeal Shockwave Therapy to Conventional Treatment Improves Pain, Function, and Electrophysiological Function in Females With Carpal Tunnel Syndrome: A Randomized Controlled Trial

Abstract

Objective

To determine whether adding extracorporeal shockwave therapy (ESWT) to conventional treatment enhances pain, function, and electrophysiological functionality in females with carpal tunnel syndrome (CTS).

Methods

One hundred females (25–40 years) diagnosed with CTS were randomly allocated to a control group that received conventional therapy and an experimental group that received the same program augmented with ESWT. Outcome measures included the symptom severity scale (SSS), function severity scale (FSS), pain intensity assessed using the visual analog scale (VAS). In addition, distal sensory latency/distal motor latency (DSL/DML), and sensory nerve conduction velocity/motor nerve conduction velocity (SNCV/MNCV) were measured using a nerve conduction velocity study.

Results

The experimental group exhibited significantly greater improvements in SSS, VAS, DSL, DML, SNCV, compared to controls (all p≤0.05). However, changes in MNCV and FSS were non-significant (p>0.05).

Conclusion

Integrating ESWT into rehabilitation enhances function, pain, and electrophysiological recovery in females with CTS.

GRAPHICAL ABSTRACT

INTRODUCTION

Carpal tunnel syndrome (CTS) is an entrapment neuropathy of median nerve in the carpal tunnel, manifesting as pain, tingling, and numbness in the thumb, index, middle, and radial half of the ring fingers, often accompanied by weakness of the thenar muscles and reduced hand function [1]. CTS risk factors include occupations involving repetitive wrist motions, fluid retention during pregnancy, and systemic diseases such as rheumatoid arthritis and diabetes mellitus [2].

Management of CTS encompasses both surgical and non-surgical approaches: physiotherapy, corticosteroid injections, orthotics, and pharmacological treatment [3]. Physical therapy modalities include laser therapy, therapeutic ultrasound, exercise therapy, manual therapy, Kinesio Taping (KT), and extracorporeal shockwave therapy (ESWT) [4-7].

ESWT has gained attention for its regenerative, anti-inflammatory, and analgesic properties. By delivering mechanical shock waves to affected tissues, ESWT increases blood flow, modulates nociceptor activity, and promotes tissue healing [1,8]. Clinical evidence supports its effectiveness in improving nerve conduction velocity (NCV) and functional performance in individuals having mild to moderate CTS [8,9].

KT is designed to relieve pain and enhance functional mobility by lifting the skin and decreasing pressure on underlying structures. KT has been demonstrated to improve circulation and lymphatic drainage, thereby reducing compression on the median nerve [10,11].

Therefore, we aimed to determine whether combining ESWT with conventional treatment enhances electrophysiological and functional outcomes more effectively than conventional treatment alone, as measured by pain, function, and electrophysiological parameters.

METHODS

Study design and participants

This randomized controlled trial was conducted between March and November 2024. The study followed the Declaration of Helsinki, approved by the Ethics Committee of the Faculty of Physical Therapy, Badr University in Cairo (IRB00014233-0), and was registered at ClinicalTrials.gov (ID: NCT06214286), with all participants providing informed consent. Eligible patients were initially referred for electrodiagnostic nerve conduction studies to confirm the diagnosis of CTS.

Sample size was calculated by G*Power software (v3.1.9; Heinrich-Heine-University) for a two-tailed test. Depending on F-tests (MANOVA: special effects and interactions), with α of 0.05, power of 0.80, an allocation ratio (N2/N1) of 1, and an effect size (d) of 0.585 derived from a pilot study, a minimum of 92 participants (47 per group) would be required, with a total sample size of 94. This calculation involved comparing two independent groups across five main dependent variable outcomes.

One hundred and twenty adult females aged 25–40 years diagnosed with CTS were screened. Participants were included if they were female, aged 25–40 years, had a diagnosis of mild to moderate CTS based on clinical diagnosis and NCV study, paresthesia in the median nerve distribution with nocturnal symptoms exacerbation, positive Phalen’s and/or Tinel’s sign, and symptom duration ≥3 months. Participants were excluded if they had a previous carpal tunnel release surgery, corticosteroid injection to the wrist within the preceding 3 months, traumatic wrist injury within the last 3 months, cervical radiculopathy, polyneuropathy, or pregnancy. Diabetic patients, patients with rheumatoid arthritis, or hypothyroidism were excluded from the study. One hundred participants met the inclusion and exclusion criteria and were randomized equally to the control or experimental group using a random number generator (https://randomizer.org). Thus, each group included 50 participants (Fig. 1).

Fig. 1.

Study flow diagram.

Interventions

All participants in both groups received a combined 6-week program comprising median nerve gliding and tendon gliding exercises (3–5 sets per day, 10 repetitions per set). Participants were provided with a neutral-position wrist splint (0°–5° extension) to be worn during nighttime throughout the intervention period. All participants received education regarding ergonomic computer use and activity modification to avoid sustained wrist flexion or forceful gripping. KT was applied over the carpal tunnel region for all participants and reapplied every 3–5 days. The KT strip was cut into a Y-shape (approximately 15–20 cm), with the base anchored at the forearm proximal to the carpal tunnel. The two tails were applied around the wrist with mild tension (10%–20%), leaving the carpal tunnel area uncovered [1].

The experimental group additionally received radial ESWT (Fig. 2) applied directly over the carpal tunnel region. Participants received 6 sessions of shockwave therapy at a frequency of 1 Hz, energy of 60 mJ, and a total of 1,200 shocks per session. Sessions were administered once weekly for six weeks with participants in a sitting position [2].

Fig. 2.

Extracorporeal shockwave therapy application.

All outcome measures were assessed by a blinded assessor unaware of the randomization or the interventions. Participants were assessed at baseline and after 6 weeks.

Outcome measures

Primary outcomes

(1) The Boston Carpal Tunnel Questionnaire

The Boston Carpal Tunnel Questionnaire is commonly used to assess symptom severity and functional status in patients with CTS and comprises a symptom severity scale (SSS) and a function severity scale (FSS). This 5-point Likert scale questionnaire includes an 11-item SSS assessing pain, numbness, tingling, and weakness, and an 8-item FSS evaluating difficulty performing daily tasks. Patients rated each item, and the instrument is valid and reliable for assessing symptom severity and function in patients with CTS, including validation in the Arabic language [3-7].

Secondary outcomes

(1) Pain intensity

Pain intensity evaluated using the visual analog scale (VAS). It ranges from 0 to 10. VAS is a valid, reliable, and sensitive tool for pain assessment [8,9].

(2) Nerve conduction study

Nerve conduction study included measuring distal sensory latency/distal motor latency (DSL/DML), and sensory nerve conduction velocity/motor nerve conduction velocity (SNCV/MNCV) to confirm CTS diagnosis and severity. Active and reference ring electrodes were placed over the second proximal and distal inter-phalangeal joints. Afterward, Median nerve was stimulated at the wrist between the palmaris longus and flexor carpi radialis tendons at about 14 cm from the active electrode (Fig. 3) [10]. MNCV was measured using a fixed 8-cm distance between the surface recording electrode over the abductor pollicis brevis muscle belly and the reference electrode located just distal to the metacarpo-phalangeal joint. Afterward, Median nerve was stimulated at the wrist and elbow, conduction velocity was calculated by dividing the distance by the time difference between the two stimulation points (Fig. 4) [11].

Fig. 3.

Sensory nerve conduction velocity study.

Fig. 4.

Motor nerve conduction velocity study.

Typical reference thresholds for sensory conduction (index finger to wrist, 14-cm distance) were DSL>3.5 ms or SNCV<50 m/s, indicating an abnormal response. For motor conduction (abductor pollicis brevis, stimulation at 8 cm), thresholds were DML>4.2 ms and MNCV<49 m/s [12,13].

Statistical analysis

Data were analyzed using IBM SPSS version 30 (IBM Corp.). Data normality was confirmed using the Shapiro–Wilk test. Data was summarized using mean and standard deviation. Unpaired t-test was used to compare basic demographic data between groups. Within-group comparisons between baseline and post-treatment were done using a paired t-test. To compare serial measurements across different time points, a repeated-measures ANOVA was used, with groups as the between-subjects factor and time points as the within-subjects factor. In addition, the interaction between group and time was also assessed. P-values less than 0.05 were considered statistically significant.

RESULTS

One hundred patients diagnosed with CTS completed this study. The mean age of participants in the experimental group was 34.12±3.12 years, while the mean age of participants in the control group was 34.64±3.02 years. There was no significant difference between the two groups regarding age (p=0.399). The mean body mass index (BMI) of group 1 was 29.6±1.6 kg/m² while the mean BMI of group 2 was 29.5±1.7 kg/m². The mean disease duration of group 1 was 23.82±7.4 months, while the mean disease duration for group 2 was 24.02±7.7 months. There was no difference between the two groups in BMI or disease duration (p=0.724, 0.581, respectively).

SSS

There was no significant difference between the two groups in SSS at baseline (p=0.350). In addition, there was a significant difference between post-treatment and baseline in both groups (p=0.001). However, between-group comparison showed no significant difference when the averages across all time points were compared (p=0.307). Nevertheless, a significant interaction between groups and time was observed in favor of the treatment group (p=0.002) (Table 1).

Table 1.

Comparison of mean pre-treatment and post-treatment scores of Boston-SSS, Boston-FSS, and VAS

Variable	Pre	Post	p-value
Boston-SSS
Control group (A)	32.44±6.37	17.18±3.51	0.001*
Experimental group (B)	33.88±8.76	13.88±2.84	0.001*
Time (Pre vs. Post)			0.001*
Group			0.307
Time×Group			0.002*
Boston-FSS
Control group (A)	27.64±3.83	10.80±1.70	0.001*
Experimental group (B)	26.58±4.29	9.06±1.74	0.001*
Time (Pre vs. Post)			0.001*
Group			0.003*
Time×Group			0.419
VAS
Control group (A)	7.02±0.71	3.70±0.71	0.001*
Experimental group (B)	7.31±1.27	2.98±0.61	0.001*
Time (Pre vs. Post)			0.001*
Group			0.141
Time×Group			0.001*

Values are presented as mean±standard deviation.

SSS, symptom severity scale; FSS, function severity scale; VAS, visual analog scale.

^*Significant at alpha level <0.05.

FSS

There was no significant difference between both groups regarding FSS at baseline (p=0.195). Besides, there was a significant difference between post-treatment and baseline in both groups (p=0.001). Besides, between-group comparison showed a significant difference when the averages across all time points were compared (p=0.003). Nevertheless, no interaction between groups and time was observed (p=0.419) (Table 1).

VAS

There was no significant difference between the two groups regarding VAS score at baseline (p=0.160). Besides, there was a significant difference between post-treatment and baseline in both groups (p=0.001). However, between-group comparison showed no significant difference when the averages across all time points were compared (p=0.141). Nevertheless, a significant interaction between groups and time was observed in favor of the treatment group (p=0.001) (Table 1).

DSL

There was no significant difference between the two groups regarding DSL at baseline (p=0.220). Besides, there was a significant difference between post-treatment and baseline in both groups (p=0.001). However, between-group comparison showed no significant difference when the averages across all time points were compared (p=0.743). Nevertheless, a significant interaction between groups and time was observed in favor of the treatment group (p=0.001) (Table 2).

Table 2.

Comparison of mean pre-treatment and post-treatment scores of the DSL, SNCV, DML, and MNCV

Variable	Pre	Post	p-value
DSL
Control group (A)	4.52±0.59	3.86±0.53	0.001*
Experimental group (B)	4.66±0.54	3.56±0.25	0.001*
Time (Pre vs. Post)			0.001*
Group			0.743
Time×Group			0.001*
SNCV
Control group (A)	44.24±3.03	47.21±2.56	0.001*
Experimental group (B)	44.36±3.54	48.76±2.46	0.001*
Time (Pre vs. Post)			0.001*
Group			0.116
Time×Group			0.006*
DML
Control group (A)	5.01±0.54	4.50±0.47	0.001*
Experimental group (B)	5.04±0.54	4.65±0.49	0.001*
Time (Pre vs. Post)			0.001*
Group			0.349
Time×Group			0.008*
MNCV
Control group (A)	48.92±0.31	49.11±0.23	0.001*
Experimental group (B)	49.03±0.32	49.33±0.36	0.001*
Time (Pre vs. Post)			0.001*
Group			0.002*
Time×Group			0.104

Values are presented as mean±standard deviation.

DSL, distal sensory latency; SNCV, sensory nerve conduction velocity; DML, distal motor latency; MNCV, motor nerve conduction velocity.

^*Significant at alpha level <0.05.

SNCV

There was no significant difference between the two groups regarding SNVC at baseline (p=0.853). Besides, there was a significant difference between post-treatment and baseline in both groups (p=0.001). However, between-group comparison showed no significant difference when the averages across all time points were compared (p=0.116). Nevertheless, a significant interaction between groups and time was observed in favor of the treatment group (p=0.006) (Table 2).

DML

There was no significant difference between the two groups regarding DML at baseline (p=0.765). Besides, there was a significant difference between post-treatment and baseline in both groups (p=0.001). However, between-group comparison showed no significant difference when the averages across all time points were compared (p=0.349). Nevertheless, a significant interaction between groups and time was observed in favor of the treatment group (p=0.008) (Table 2).

MNCV

There was no significant difference between both groups regarding MNVC at baseline (p=0.084), In addition, there was a significant difference between post-treatment and baseline in both groups (p=0.001). In addition, between groups comparison showed a significant difference when the averages across all time points were compared (p=0.002). Nevertheless, no interaction between groups and time was observed (p=0.104) (Table 2).

DISCUSSION

The current study examined the therapeutic impact of integrating ESWT into a conventional physiotherapy program for females with CTS. Both groups demonstrated significant improvements across all outcomes relative to baseline. Nonetheless, the experimental group showed significantly greater post-treatment improvements in SSS, SNCV, DSL, DML, and VAS score compared to the control group. However, there was no difference between groups regarding MNCV or FSS.

The current study demonstrated significant improvement in both groups, indicating the effectiveness of the physical therapy program in treating patients with CTS.

Night splinting in the current study was utilized to maintain the wrist in a neutral position during rest, thereby minimizing intracarpal pressure and mitigating nocturnal symptoms. A Cochrane systematic review reported modest short-term benefits of wrist splinting for pain relief and functional improvement compared to no treatment, although evidence supporting long-term efficacy remains limited [14]. More recent randomized trials suggest that combined daytime and nighttime splinting yields superior pain reduction and greater improvements in functional ability alongside quality of life relative to nighttime-only splinting or no splinting [15].

The conservative treatment in the current study also includes tendon and nerve gliding exercises, which are an essential component of conventional CTS rehabilitation and aim to enhance median nerve mobility and reduce perineural compression. Evidence indicates that incorporating these exercises into standard splinting protocols results in greater improvements in symptom severity and sensory function than splinting alone [16,17]. Proposed mechanisms include reduced intraneural adhesions, improved microcirculation, and support for median nerve recovery, with minimal adverse effects. Evidence suggests its efficacy when combined with other conservative treatments [18].

In addition, KT was applied to all participants in both groups. de Sire et al. [19] reported that KT significantly improved hand function in CTS, potentially through enhanced local circulation and reduced inflammatory compression on the median nerve.

Participants in the experimental group received ESWT along with conservative treatment. Participants in the experimental group showed greater improvements in symptom severity, pain intensity reduction, SDL, MDL, and SNCV than those in the control group. ESWT has been shown to induce biological effects, including neovascularization, nitric oxide–mediated anti-inflammatory activity, and neural regeneration [2]. These mechanisms may alleviate mechanical compression by minimizing perineural inflammation and edema in the carpal tunnel [20].

Our findings align with emerging evidence supporting the therapeutic role of ESWT in peripheral neuropathies, including CTS. ESWT has been reported to enhance nerve regeneration, reduce intraneural edema, and modulate inflammatory mediators, thereby improving sensory nerve conduction and symptom perception [20]. The superior clinical outcomes observed in the experimental group suggest a synergistic effect of combining ESWT with conventional rehabilitation, potentially promoting biological recovery through improved vascularization, decreased inflammation, and accelerated median nerve regeneration [2,10].

Consistently, a meta-analysis by Zhang et al. [21] demonstrated that ESWT significantly improved pain, function, and electrodiagnostic parameters in mild-to-moderate CTS compared with control interventions. Similarly, Seok and Kim [13] reported superior medium-term outcomes with ESWT compared with corticosteroid injections. The positive effects observed in our study may reflect the cumulative impact of ESWT on vascular repair and axonal regeneration.

According to Chen et al. [1], the therapeutic effects of ESWT may be time-limited, with significant benefits observed at four weeks that attenuated thereafter. This suggests that the long-term effectiveness of ESWT may depend on treatment duration and combination with other therapeutic modalities.

The results also showed no difference between groups regarding MNCV or FSS. The reason behind this can be attributed to the difference in the regeneration velocity of sensory and motor nerves [22]. ESWT improves local blood flow and vascularization; thus, superficial sensory nerve improves faster than deeper motor nerves [23].

The results of the current study align with those of Habibzadeh et al. [24], who reported a significant difference between the ESWT group and the conventional treatment in SSS, SDL, and MDL. They also reported no difference in the FSS between groups. The current study also assessed the SNCV and MNCV. However, difference between the ESWT group and the conventional group was only detected in the SNCV in favor of the ESWT group.

The absence of a significant between-group difference in MNCV, related to the slower regeneration rate of motor fibers compared with sensory fibers, as well as the relatively short six-week intervention period, could explain the lack of difference between the two groups in FSS. Function improvement may require a longer time before it can be detected [25,26].

The difference between the results of the current study and those of Raissi et al. [27] may be due to differences in ESWT dosage and parameters as they applied only 3 sessions, whereas the current study applied 6 sessions. Their study reported only the difference between the ESWT and the conventional treatment group in terms of SDL. However, they couldn’t detect a difference in either function, DML, pain intensity, or NCV. In the current study, there was a difference in favor of the ESWT group in SSS, SNCV, DSL, DML, and VAS score after 6 ESWT sessions.

Limitations and future directions

The study included only female participants, which may limit generalizability to males with CTS. Additionally, the six-week intervention period and lack of long-term follow-up preclude conclusions regarding sustained efficacy. Future studies should include both genders and incorporate extended follow-up durations.

Conclusion

Integrating ESWT with conventional conservative treatment yielded superior therapeutic outcomes in females with mild-to-moderate CTS. The combined intervention significantly improved function, reduced pain, and improved electrophysiological parameters compared with conservative treatment alone. These findings suggest a synergistic interaction between the biological effects of ESWT and the mechanical benefits of conventional rehabilitation. This combined approach represents a safe, non-invasive, and effective rehabilitation strategy that may serve as an optimal conservative option for CTS management before considering more invasive interventions.