Research Review By Dr. Joshua Plener©


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Date Posted:

March 2021

Study Title:

Manual Therapy Versus Surgery for Carpal Tunnel Syndrome: 4-Year Follow-Up from a Randomized Controlled Trial


Fernández-de-las-Peñas C, Arias-Buría J, Cleland J et al.

Author's Affiliations:

Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, Spain; Physical Therapy Program, Department of Public Health and Community Medicine, Tufts University School of Medicine, Boston, MA, USA

Publication Information:

Physical Therapy 2020; 100: 1987-1996.

Background Information:

Carpal tunnel syndrome is reported to be the most common upper extremity entrapment neuropathy with an estimated incidence of 542 per 100 000 in women, and a prevalence ranging from 6.3% to 11.7% depending on case definition (1, 2). Furthermore, as carpal tunnel syndrome significantly affects the middle-aged active worker, there is a substantial health care cost and economic burden associated with this condition.

Current treatment guidelines recommend different interventions such as orthoses, exercise and manual therapy, however, surgery continues to be the most common treatment approach for carpal tunnel syndrome (3-5). Typically, conservative treatments such as splinting, laser, and steroid injections are provided locally. However, past research has demonstrated that treating carpal tunnel syndrome through desensitization maneuvers of the central nervous system can provide superior short-term outcomes and similar long-term outcomes for pain intensity and function when compared to surgery (6).

Most studies assessing carpal tunnel syndrome include a 1-year follow-up period (7). The objective of this current study is to investigate the 4-year effect of manual therapy compared to carpal tunnel release surgery in a cohort of women with carpal tunnel syndrome, and to determine the surgical recurrence rate of post-treatment carpal tunnel release surgery (7).

Pertinent Results:

The original trial included 120 participants, with 60 per group. 111 completed the 1-year follow-up and 97 completed the 4-year follow up. Despite 23 participants not completing the 4-year follow-up, baseline scores between the initial sample and the 4-year follow-up sample didn’t significantly differ.

The original study demonstrated that the manual therapy group exhibited a greater decrease in average pain intensity at 1 and 3 months and a greater decrease of their worst pain intensity at 1, 3 and 6 months compared to those receiving surgery. At both the 1- and 4-year follow ups, there were no significant differences between the groups.

Participants’ self-perceived improvement, assessed with the Global Rating of Change scale, was similar between both groups at the 1- and 4-year follow-ups. As well, there were no significant between group differences in the rate of surgery during the 4-year follow up period. In the manual therapy group, 9 received surgery, 3 before the 1-year follow-up and 6 during the 4-year follow-up. Four participants in the surgery group received surgery or repeat surgery during the 1-year follow up and another 4 during the 4-year follow-up period. There were no significant differences for participants seeking other conservative interventions between the groups, with a minority of participants receiving infrequent physical therapy treatment for pain during the 4-year follow-up period.

Clinical Application & Conclusions:

The original randomized controlled trial demonstrated that in the short term, the manual therapy group had significantly greater relief of symptoms and function at 1 and 3 months. Both groups experienced significant and clinically important improvements from baseline to follow up, particularly at 6 and 12 months. The between group differences became non-significant at 12 months.

This current study featuring a 4-yr follow up found that manual therapy consisting of desensitization maneuvers combined with a tendon and nerve gliding exercise program (and cervical mobilizations) resulted in similar long-term outcomes in pain and function compared to surgery. Only 15% of participants within the manual therapy group required surgery within the 4-year follow-up period after the initial intervention. This finding is contrary to previous research that reported up to 60% of conservatively treated patients requiring surgery (8). This may be explained as past studies mainly used local treatments, based on the traditional premise that carpal tunnel syndrome is considered a localized pathology with peripheral lesions at the carpal tunnel. However, current evidence (and our evolving clinical understanding) suggests that carpal tunnel syndrome is a complex disorder, exhibiting sensitization mechanisms (9, 10). This study demonstrated that it may be more effective to provide desensitization maneuvers compared to localized interventions targeted at the hand and/or wrist. Further research needs to be conducted in order to understand this relationship better.

The results of this study suggest that a conservative approach may be a viable first-line treatment option before surgery. However, the type of conservative treatment approach appears to be important, as patients who receive a localized conservative treatment approach appears to have inferior outcomes (11). In addition, there is a lack of consensus on which patients are ideal candidates for either conservative or surgical intervention, therefore better identification of which patients would be better suited for each treatment option could improve clinical outcomes.

Reviewers comment: The results of this study appear very promising, but we can’t jump to the conclusion that ‘3 sessions of manual therapy’ is the answer for carpal tunnel syndrome. This study didn’t have a control group, so we can’t discount the role of natural history, and both groups received nerve/tendon gliding exercises, so we can’t discount these exercises as the potential main the driving factor for recovery. The paper provided a very interesting approach to the treatment of carpal tunnel syndrome, which is probably similar to the way some of us already treat this condition! More research needs to be conducted in order to strengthen this paper’s arguments, but the results of the potential long term impact of a short-course of manual therapy (especially when compared to an invasive surgery) is very exciting!

Study Methods:

This study was a continuation of a previous randomized controlled trial performed in Spain.

Inclusion Criteria:
  • Women with clinical and electrophysiological findings of carpal tunnel syndrome
  • Participants had to exhibit symptoms such as pain or paresthesia in the median nerve distribution, and increasing symptoms at night
  • Clinical signs such as Tinel and Phalen signs
  • Symptoms have persisted for at least 12 months
  • Electrodiagnostic deficits with a median nerve conduction velocity < 40 m/s and median nerve distal motor latency > 4.20 milliseconds.
Exclusion Criteria:
  • Sensory/motor deficits in the ulnar or radial nerves
  • Age more than 65 years of age
  • Previous hand surgery or steroid injection treatment
  • Multiple diagnoses in the upper extremity
  • Cervical and/or upper extremity trauma
  • Any systemic disease as a cause of carpal tunnel syndrome (such as diabetes mellitus and thyroid disease)
  • Comorbid musculoskeletal pain conditions such as rheumatoid arthritis or fibromyalgia
  • Pregnancy
  • Presence of depressive symptoms defined as the Beck Depression Inventory-2 score of greater than 8 points
Patients were randomly assigned to receive either manual therapy or surgery. A computer-generated randomized table of numbers was created by an external statistician not involved in other study parts. A different researcher opened the sealed opaque envelopes and proceeded with the treatment allocation. Due to the interventions used, therapists and patients were not blinded, however, the clinician who collected follow-up data was blinded to group allocations.

Manual Therapy Intervention:
Physiotherapists with at least 6 years of clinical experience performed soft tissue mobilization and nerve/tendon gliding exercises. Patients within this group received 3 treatment sessions, once per week, consisting of desensitization maneuvers of the central nervous system for a duration of 30 minutes. The desensitization maneuvers were soft tissue mobilization techniques targeting anatomically-related sites that potentially could cause entrapment of the median nerve such as scalene muscles, pectoralis minor muscle, biceps brachii, pronator teres muscle and transverse carpal ligament. In addition, lateral glide mobilization of the cervical spine and tendon/nerve gliding exercises were performed. The site of treatment was determined by the clinician and treated according to clinical findings of pain on palpation and reproduction of sensory or motor symptoms.

At the last treatment appointment, the physiotherapist provided education on tendon and nerve gliding exercises as homework if necessary. In addition, patients were asked to not modify any work or activity levels.

Surgical Intervention:
The surgery group underwent open or endoscopic release of the carpal tunnel which was based on the preference of the surgeons and patients (neither procedure has shown superior results) (12). In addition, patients received the same education sessions for performing tendon/nerve gliding exercises as the manual therapy group.

The primary outcome was hand pain based on an 11-point numeric rating scale (NRS). Pain was assessed at their current level of hand pain and the worst level of pain experienced in the preceding week. A change of 2 points or a 30% decrease in baseline scores was considered clinically relevant as no minimal clinically important difference (MCID) exists for hand pain (13).

Secondary outcomes included the functional status and symptom severity subscale of the Boston Carpal Tunnel Questionnaire (14) and self-perceived improvement with the Global Rating of Change score. On the Boston Carpal Tunnel Questionnaire, higher scores indicate worse function and greater symptom severity. The MCID is determined to be 0.74 for the function subscale and 1.14 points for the symptom severity subscale (15). The Global Rating of Change scores of +4 and +5 are indicative of moderate changes in patients’ status, where scores of +6 and +7 indicate large changes.

Successful outcomes were defined when at least 1 of the following items based on their respective MCID was present:
  • A reduction of ≥ 0.74 points or 1.14 points on the Boston Carpal Tunnel Questionnaire function or symptom severity score respectively
  • A decrease of 2 or more or a 30% reduction in hand pain intensity
Furthermore, the rate of surgical interventions in the manual therapy group or repeat surgery in the surgical group during the follow-up periods was assessed. Participants were also asked if they received other conservative treatments during the 4-year follow-up period.

Data Analysis:
The sample size was initially calculated to detect clinical changes in hand pain intensity at 1-year follow up. An analysis was performed according to intention-to-treat principles, and since this long-term follow up was a non-inferiority study, a per-protocol analysis was also conducted. Standard mean differences were calculated by dividing the between group difference mean score by the pooled standard deviation, if significant differences were observed. Chi square tests were used to compare the self-perceived improvement as assessed with the global rating of change, and success rates at 1- and 4-year follow-up periods. Chi square tests were also used for detecting between group differences within the surgical intervention rates and the use of other conservative treatments during the 4-year follow-up period.

Study Strengths / Weaknesses:

  • This is the first study to investigate the effects of manual therapy for carpal tunnel syndrome using a longer 4-year follow-up period.
  • The application of the manual therapy was applied based on clinical reasoning and the current nociceptive theories of carpal tunnel syndrome.
  • There was only a 20% loss to follow-up over the 4-year follow-up period, which was similar in both groups.
  • It is difficult to determine the effect of desensitization maneuvers, as both groups received a tendon/nerve gliding exercise program as homework/selfcare.
  • We can’t rule out the role of “other” treatments participants received during the 4 year follow up period, however the rate of participants receiving these interventions were similar between groups.
  • There were generally strict inclusion and exclusion criteria which may limit generalizability of the results.
  • Due to the nature of the treatment, patients and clinicians were not blinded.
  • The role of psychological variables such as mood disorders can’t be discounted as they weren’t controlled for.
  • The provocative tests on physical examination were not reassessed at any follow-up period.
  • The number of manual therapy sessions was an arbitrary number as no available data exists for the frequency and dose of therapy. A greater number of sessions may demonstrate superior results.
  • Only women with carpal tunnel syndrome were included, therefore limiting the generalizability of these results.

Additional References:

  1. Gelfman R, Melton LJ III, Yawn BP et al. Long-term trends in carpal tunnel syndrome. Neurology 2009; 72: 33–41.
  2. Thiese MS, Gerr F, Hegmann KT et al. Effects of varying case definition on carpal tunnel syndrome prevalence estimates in a pooled cohort. Arch Phys Med Rehabil 2014; 95: 2320–2326.
  3. Huisstede BM, Fridén J, Coert JH et al. European HANDGUIDE group. Carpal tunnel syndrome: hand surgeons, hand therapists, and physical medicine and rehabilitation physicians agree on a multidisciplinary treatment guideline—results from the European HANDGUIDE study. Arch Phys Med Rehabil 2014; 95: 2253–2263.
  4. Erickson M, Lawrence M, Jansen CWS et al. Hand pain and sensory deficits: carpal tunnel syndrome. J Orthop Sports Phys Ther 2019; 49: CPG1–CPG8.
  5. Management of carpal tunnel syndrome evidence-based clinical practice guideline. American Academy of Orthopaedic Surgeons. 2016. Accessed September 2019.
  6. Fernández-de-las Peñas C, Ortega-Santiago R, de la Llave-Rincón AI et al. Manual physical therapy versus surgery for carpal tunnel syndrome: a randomized parallel-group trial. J Pain 2015; 16: 1087–1089.
  7. Louie D, Earp B, Blazar P. Long-term outcomes of carpal tunnel release: a critical review of the literature. Hand 2012; 7: 242–246.
  8. Burton CL, Chesterton LS, Chen Y, et al. Clinical course and prognostic factors in conservatively managed carpal tunnel syndrome: a systematic review. Arch Phys Med Rehabil 2016; 97: 836–852.
  9. Fernández-de-las-Peñas C, de-la-Llave-Rincón AI, Fernández-Carnero J, et al. Bilateral widespread mechanical pain sensitivity in carpal tunnel syndrome: evidence of central processing in unilateral neuropathy. Brain 2009; 132: 1472–1479.
  10. Zanette G, Cacciatori C, Tamburin S. Central sensitization in carpal tunnel syndrome with extraterritorial spread of sensory symptoms. Pain 2010; 148: 227–236.
  11. Cha SM, Shin HD, Ahn JS, et al. Differences in the postoperative outcomes according to the primary treatment options chosen by patients with carpal tunnel syndrome. Ann Plast Surg 2016; 77: 80–84.
  12. Zuo D, Zhou Z, Wang H et al. Endoscopic versus open carpal tunnel release for idiopathic carpal tunnel syndrome: a meta-analysis of randomized controlled trials. J Orthop Surg Res 2015; 10: 12.
  13. Farrar JT, Young JP Jr, LaMoreaux L, et al. Clinical importance of changes in chronic pain intensity measured on an 11-point numerical pain rating scale. Pain 2001; 94: 149–158.
  14. Rosales RS, Benseny E, Díez de la Lastra-Bosch I. Evaluation of the Spanish version of the DASH and carpal tunnel syndrome health-related quality of life instruments: cross cultural adaptation process and reliability. J Hand Surg 2002; 27A: 334–343.
  15. Kim JK, Jeon SH. Minimal clinically important differences in the carpal tunnel questionnaire after carpal tunnel release. J Hand Surg Eur 2013; 38: 75–79.

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