Research Review by Gary Maguire©

Audio:

Download MP3

Date Posted:

October 2010

Study Title:

Carpal Tunnel Syndrome. Part I Effectiveness of Nonsurgical Treatments - A Systematic Review

Authors:

Huisstede BM et al.

Author's Affiliations:

Department of General Practice and Rehabilitation Medicine, Erasmus Medical Center, Rotterdam, The Netherlands.

Publication Information:

Archives of Physical Medicine & Rehabilitation 2010; 91: 981-1004.

Background Information:

Carpal Tunnel Syndrome (CTS) is caused by compression of the median nerve as it passes through the carpal tunnel and is characterized by pain, paresthesia and numbness in the fingers and hand (in the median nerve distribution), all of which are often exacerbated at night. CTS is thought to be the most common nerve entrapment syndrome in the upper limb. Work-related CTS represents a significant burden in terms of disability and worker’s compensation costs.

Anterior View of the Carpal Tunnel
While the exact pathophysiology of how pressure in the carpal tunnel increases over time remains unclear, evidence suggests that CTS is associated with an average hand force requirement of >4Kg, repetitive work tasks (cycle time < 10s, or > 50% of cycle time performing the same movements) and a daily 8-hour energy-equivalent frequency-weighted acceleration of 3.9 m/s. To simplify, it is a repetitive strain disorder.

Although many interventions have been suggested as treatments for CTS (both non-surgical and surgical), no therapy is universally accepted (1). Currently in the United States, 400,000 CTS operations are performed each year costing a total of $2 billion. Non-surgical treatment options vary, from rest and activity modification to splinting, oral medication (nonsteroidal anti-inflammatory or oral steroids), ultrasound, yoga and carpal bone mobilization.

In this paper, the authors sought to optimize the quality of CTS patient care by systematically reviewing scientific literature to provide an up-to-date overview of the evidence for the effectiveness of non-surgical interventions to treat CTS.

Pertinent Results:

A total of 53 RCTs were identified in the author’s systematic review process (29 studies or 55% were of high quality, and 8% of the studies scored 40% to 50% of the total possible score [using the Cochrane Collaboration criteria]). Based on this evidence the following treatment approaches were identified (for the Cochrane review of O’Connor): splinting, ultrasound, ergonomic keyboards, oral medication, vitamins, exercise, yoga, mobilization, magnet therapy, chiropractic care, laser and acupuncture.

Eighteen RCTs were found for the effectiveness of: splinting, ultrasound, laser, oral medication, manual therapy, magnetic field stimulation, acupuncture, massage therapy, heat wrap therapy, cupping therapy, botulinum B toxin, iontophoresis and exercise.

Findings:
  • Splinting: When comparing wrist splinting in neutral position versus wrist position in 20° of extension, wrist splint in neutral is more effective (over a short term period of 2 weeks). Night splinting is more effective than no treatment for symptom improvement. When full-time use of a wrist splint is compared with night-only use there is no statistical difference for functional improvement or a reduction of symptoms (measured over 6-weeks). Wrist splints versus hand braces at night are both equal for overall effectiveness. When tendon and nerve gliding exercises are used as an additive treatment with splints or even with the further addition of ultrasound there is no evidence for increased effectiveness versus splinting only. There does appear to be moderate evidence from a high-quality RCT that oral steroids (prednisone) are more effective for the treatment of CTS than wrist splinting. The combination of low-level laser therapy and splinting does not provide any additional benefit versus splinting only. The same applies for yoga and splinting versus splinting only.
  • Ultrasound: The comparison of ultrasound versus placebo reveals that ultrasound is more effective for CTS at 7 weeks of follow-up and in the midterm. When utilizing ultrasound for CTS treatment, intensities of 1.5W/cm² or 0.8W/cm² and frequencies of 1 or 3MHz seem equally effective. When comparing ultrasound to laser therapy the evidence supports that ultrasound is more effective for treating CTS in the short term.
  • Laser Therapy: Three recent studies continue to demonstrate that low level laser therapy does not provide any benefit in the treatment of CTS compared to placebo.
  • Oral Medications and Vitamins: Multiple studies continue to demonstrate that oral steroids are more effective than placebo involving symptom improvement after 2 weeks. There is strong evidence of benefit with 2 weeks of use and moderate benefit after 4 weeks of use. There is no conclusive support for the effectiveness of anti-inflammatory drugs, diuretics or vitamin B6 in the treatment of CTS.
  • Chiropractic Treatment: There is no evidence to support that chiropractic treatment (manual thrusts, myofascial massage or loading) is effective for treating CTS.
  • Manual Therapy or Mobilization: There appears to be limited evidence that carpal bone mobilization is more effective than no treatment in short term functional progress. The use of neurodynamic techniques, Graston instrument-assisted soft tissue treatment, home exercise or soft tissue mobilization combined with splinting does not provide any better results than splinting only.
  • Ergonomic Keyboards: The use of Microsoft (natural keyboard) and Apple (adjusTable) keyboards were found to be moderately beneficial in reducing pain and improving hand function when compared to using a standard keyboard in the short term.
  • Magnet Therapy: A high-quality RCT (n=30) was performed comparing magnet therapy with placebo in the reduction of pain. After a 2 week follow-up there was no evidence for the effectiveness of magnet therapy in the treatment of CTS.
  • Magnetic Field Therapy: The use of dynamic magnetic field therapy in the short term has moderate effectiveness. Significant differences were found in a high-quality study (Weintraub and Cole) on the Neuropathy Pain Scale with 42% reduction of symptoms in the treatment group and 24% in the control group. No significant differences were found for pain or the Patients Clinical Global Impression of Change at a 2 month reassessment.
  • Acupuncture: Studies performed using laser acupuncture and acupuncture compared with oral steroids did not provide any benefit in the treatment of carpal tunnel syndrome.
  • Massage Therapy: There is supporting evidence from several studies that conclude that a targeted massage protocol is more effective than a general massage protocol. Evidence also suggests that massage therapy for 15 minutes 1x/week with daily self massage is more effective than no treatment for CTS improving overall strength and reduction of tingling, numbness, burning and pain.
  • Heat Wrap Therapy: The use of low-level heat wrap therapy appears to have some benefit over a short term (3 days follow up) in the reduction of pain compared to an oral placebo. Functional changes were noted with improved grip strength, pain reduction and joint stiffness.
  • Cupping Therapy: Although not a wide spread clinical treatment the use of cupping therapy is more effective than heat pads. A high-quality study of Michalsen et al. demonstrated significant differences on pain at rest 7 days after follow up (2). The authors support that there is moderate evidence for its effectiveness but further research is required.
  • Injections other than Steroids: There appears to be no evidence that the use of botulinum B toxin injections compared to ibuprofen and splinting has any benefit in treating CTS.
  • Insulin as an Additive to a Steroid Injection: A high-quality study performed by Ozkul et al. demonstrated that insulin as an additive to steroid injection (methyl-prednisolone 20mg in 1mL) is more effective than a steroid injection for CTS treatment (3). These injections were performed on a select patient group - noninsulin-dependent diabetes mellitus patients with CTS (this limits the applicability of these findings). Treatment outcome was measured using the Global Symptom scale at 8 weeks follow up.
  • Iontophoresis: Although a high-quality study compared the effectiveness of dexamethasone iontophoresis compared with a placebo the outcome did not support any findings for the effectiveness of this type of CTS treatment approach.
  • Corticosteroid Injections: The pooling of data (RR=2.58; 95% CI, 1.72-3.87) from 2 high-quality studies (n=60) and (n=81) provides strong evidence that a local corticosteroid injection versus placebo injection or other non surgical intervention improves the clinical outcome of CTS patients. Local corticosteroid injections are also more effective than a systemic injection or the use of oral steroids. Corticosteroid injection, however, when compared to the effectiveness of anti-inflammatory medication plus splinting is not any more effective for CTS intervention. Corticosteroid injections appear to have more effectiveness than CTS treatment than using helium-neon laser. When dosage of hydrocortisone local injections are measured for effectiveness studies revealed that 25mg is not as effective as 100mg. Methylprednisone injection studies have revealed that 60mg is more effective than 20 or 40 mg in the midterm but not over the long term. When comparing the effectiveness of a single versus 2 local corticosteroid injections with 15mg methylprednisone there is no difference (in the short, mid or long term). Different approaches of applying corticosteroid injections have also been investigated with no evidence of any new novel approach versus the classic protocol. When comparing cortisone injections (40mg) to daily use of eutectic mixture of local anesthetic (EMLA) there appears to be inconclusive evidence as the study did not make comparisons between the two groups. The authors therefore concluded that the low-quality study did not merit any evidence to support the effectiveness of CTS treatment of 1 steroid injection compared to EMLA.

Clinical Application & Conclusions:

There appears to be moderate to strong evidence for the short-term effectiveness of non-surgical interventions for CTS including: oral steroids, steroid injections, electromagnetic field therapy, ergonomic keyboards, cupping therapy (short term), night splinting and ultrasound (also midterm). With the exception of oral oral/injected steroids, no longer-term results were found for any of these treatments.

The majority of the review focused on the strong and moderate evidence for the effectiveness of corticosteroids (oral and injected) with injections providing the most benefit. Studies continue to support that injections do not have any positive long term results – although for these patients, sometimes short term relief is the primary goal. The mechanism for effectiveness of corticosteroids continues to remain unclear at this time but there appears to be an anti-inflammatory or neovascular involvement. There is also concern for common side effects from steroid injections including osteonecrosis and tendon rupture.

Overall, splinting provides a safe CTS intervention with a patient achieving favorable short term outcome with night splinting appearing to be a bit more beneficial versus using the splint on a continuous basis.

Prudent clinicians will discuss these options with patients and address additional areas of complaint or dysfunction that may affect the symptomatology of CTS (ex. cervical spine structures, soft tissue structures along the course of the median nerve etc.).

Study Methods:

The authors searched the Cochrane Library as well as searching for relevant RCTs in PubMed, EMBASE, CINAHL and PEDro. To be eligible for inclusion studies had to include patients with CTS not caused by an acute trauma or any systemic disease and evaluate an intervention for treating the disorder, measuring outcomes of pain, function or recovery.

The reviewers aimed to create a categorization of relevant literature and then extract data and methodologically evaluate the quality of the literature. A data synthesis was then established, ranking the level of evidence from strong (? 75% if trials reporting consistent findings) to conflicting evidence of effectiveness on down to no systematic review or RCT found.<>

Study Strengths / Weaknesses:

The overall study does provide a strong systematic review of literature concerning the effectiveness of non-surgical interventions for the treatment of carpal tunnel syndrome. From the findings it is evident that more research needs to be performed to develop a long term treatment approach as all the various therapeutic interventions only provide short to midterm symptomatic relief. One positive aspect of the study is that it does reveal that CTS preventive measures have been developed with the advent of ergonomic keyboards, with promising results.

Additional References:

  1. Rosenbaum RB et al. Carpal tunnel syndrome and other disorders of the median nerve. Soneham: Butterworth-Heinemann;1993.
  2. Michalsen AB et al. Effects of traditional cupping in patients with carpal tunnel syndrome: a randomized controlled trial. J Pain. 1998;10.
  3. Ozkul Y et al. Local insulin injection improves median nerve regeneration in NIDDM patients with carpal tunnel syndrome. Eur J Neurol. 2001; 8.

EDITOR’S NOTE:

The authors of this paper also published a systematic review on surgical and post-surgical interventions for CTS. Interested readers can review the paper (referenced below) but I will quote their conclusion here:

”Surgical treatment seems to be more effective than splinting or anti-inflammatory drugs plus hand therapy in the midterm and long term to treat CTS. However, there is no unequivocal evidence that suggests one surgical treatment is more effective than the other. More research is needed to study conservative to surgical treatment in which also should be taken into account the optimal timing of surgery. Future research should also concentrate on optimal presurgical and postsurgical treatment programs.”

Reference:
Huisstede BM et al. Carpal Tunnel Syndrome. Part 2: Effectiveness of Surgical Treatments – A systematic review. Arch Phys Med Rehabil 2010; 91: 1005-1024.