Are extramedian symptoms associated with peripheral causes in patient with carpal tunnel syndrome? Electrodiagnostic and ultrasonographic study

Carpal Tunnel Syndrome: Neuropathic Pain Associated or Not with a Nociplastic Condition

Carpal tunnel syndrome (CTS) has been traditionally classified as primarily a neuropathic condition with or without pain. Precision medicine refers to an evidence-based method of grouping patients based on their susceptibility to biology, prognosis of a particular disease, or in their response to a specific treatment, and tailoring specific treatments accordingly. In 2021, the International Association for the Study of Pain (IASP) proposed a grading system for classifying patients into nociceptive, neuropathic, or nociplastic phenotypes. This position paper presents data supporting the possibility of subgrouping individuals with specific CTS related-pain into nociceptive, neuropathic, nociplastic or mixed-type phenotypes. Carpal tunnel syndrome is a neuropathic condition but can also be comorbid with a nociplastic pain condition. The presence of extra-median symptoms and the development of facilitated pain processing seem to be signs suggesting that specific CTS cases can be classified as the nociplastic pain phenotype. The clinical responses of therapeutic approaches for the management of CTS are inconclusive. Accordingly, the ability to identify the predominant pain phenotype in patients with CTS could likely be problematic for producing efficient treatment outcomes. In fact, the presence of a nociplastic or mixed-type pain phenotype would explain the lack of clinical effect of treatment interventions targeting the carpal tunnel area selectively. We propose a clinical decision tree by using the 2021 IASP classification criteria for identifying the predominant pain phenotype in people with CTS-related pain, albeit CTS being a priori a neuropathic pain condition. The identification of a nociplastic-associated condition requires a more nuanced multimodal treatment approach to achieve better treatment outcomes.

Effect of Perineural Dextrose Injection on Ulnar Neuropathy at the Elbow: A Randomized, Controlled, Double-Blind Study

OBJECTIVE

To compare perineural dextrose injection efficacy in the treatment of ulnar neuropathy at the elbow with a control group.

DESIGN

Prospective, double-blind, randomized, control study.

SETTINGS

Training and Research Hospital Participants: The study was completed with 40 patients with ulnar neuropathy at the elbow Intervention: Normal saline (0.9% NaCl) was injected to the control group (n=20; mean age=38.1 ± 10.7 years; median duration of symptoms = 4.5 months), while 5% dextrose (D5W) was injected to the dextrose group (n=20; mean age=43.6 ±13.5 years; median duration of symptoms = 5 months), perineurally under ultrasound guidance twice at two-week intervals. US-guided perineural injection of 1 cc each was administered into the ulnar nerve, 2 cm and 4 cm distal to the medial epicondyle, at the level of the medial epicondyle, and 2 cm and 4 cm proximal to the medial epicondyle. Amount of total fluid injected was 5 cc.

MAIN OUTCOME MEASURE(S)

At baseline, weeks 2, 4, and 12, the patients were evaluated with the Visual Analog Scale for pain and the Disabilities of the Arm Shoulder and Hand (Quick-DASH) questionnaire for disability. Electrophysiological evaluation was performed with ulnar nerve conduction studies, and the ulnar nerve cross-sectional area (CSA) was measured on ultrasonography.

RESULTS

The improvements in pain, disability, ulnar motor nerve velocity and CSA in the dextrose group were superior to those in the control group, especially at weeks 4 and 12 (p<0.001, using independent-samples t-test).

CONCLUSION

Perineural D5W may be an effective alternative therapy for those with ulnar neuropathy at the elbow for up to the 12^th week.

The Utilization of Joint Mobilization As Part of a Comprehensive Program to Manage Carpal Tunnel Syndrome: A Systematic Review

OBJECTIVE

The purpose of this review is to identify the role of joint mobilization for individuals with Carpal tunnel syndrome (CTS).

METHODS

A systematic search of 5 electronic databases (PubMed, CINAHL, Scopus, Cochrane Central Register of Controlled Trials, and SPORTDiscus) was performed to identify eligible full-text randomized clinical trials related to the clinical question. Joint mobilization had to be included in one arm of the randomized clinical trials to be included. Two reviewers independently participated in each step of the screening process. A blinded third reviewer assisted in cases of discrepancy. The PEDro scale was used to assess quality.

RESULTS

Ten articles were included after screening 2068 titles. In each article where joint mobilization was used, positive effects in pain, function, or additional outcomes were noted. In most cases, the intervention group integrating joint mobilization performed better than the comparison group not receiving joint techniques.

CONCLUSION

In the articles reviewed, joint mobilization was associated with positive clinical effects for persons with CTS. No studies used joint mobilization in isolation; therefore, results must be interpreted cautiously. This review indicates that joint mobilization might be a useful adjunctive intervention in the management of CTS.

Understanding central sensitization for advances in management of carpal tunnel syndrome

Carpal tunnel syndrome is the most common nerve compression disorder of the upper extremity, and it is traditionally considered a peripheral neuropathy associated with a localized compression of the median nerve just at the level of the carpal tunnel. Surgery and physiotherapy are treatment approaches commonly used for this condition; however, conflicting clinical outcomes suggest that carpal tunnel syndrome may be more complex. There is evidence supporting the role of peripheral nociception from the median nerve in carpal tunnel syndrome; however, emerging evidence also suggests a potential role of central sensitization. The presence of spreading pain symptoms (e.g. proximal pain), widespread sensory changes, or bilateral motor control impairments in people presenting with strictly unilateral sensory symptoms supports the presence of spinal cord changes. Interestingly, bilateral sensory and motor changes are not directly associated with electrodiagnostic findings. Other studies have also reported that patients presenting with carpal tunnel syndrome exhibit neuroplastic brainstem change supporting central sensitization. Current data would support the presence of a central sensitization process, mediated by the peripheral drive originating in the compression of the median nerve, in people with carpal tunnel syndrome. The presence of altered nociceptive gain processing should be considered in the treatment of carpal tunnel syndrome by integrating therapeutic approaches aiming to modulate long-lasting nociceptive barrage into the central nervous system (peripheral drive) and strategies aiming to activate endogenous pain networks (central drive).

Carpal tunnel syndrome: just a peripheral neuropathy?

Carpal tunnel syndrome (CTS) is considered just a peripheral neuropathy of the upper extremity associated to the compression of the median nerve. There is evidence suggesting the presence of complex sensitization mechanisms in CTS. These processes are manifested by symptoms in extra-median regions and the presence of bilateral sensory and motor impairments. These sensory and motor changes are not associated to electrodiagnostic findings. The presence of sensitization mechanisms suggests that CTS should not be considered just as a peripheral neuropathy. The presence of altered nociceptive gain processing should be considered for therapeutic management of CTS by considering the application of therapeutic interventions that modulate nociceptive barrage into the CNS.