Carpal tunnel syndrome: updated evidence and new questions

Values and Diagnostic Accuracy of Electrodiagnostic Findings in Carpal Tunnel Syndrome Based on Age, Gender, and Diabetes

BACKGROUND

Appropriate cut-off values and diagnostic accuracy (DA) [sensitivity, specificity, predictive values, positive (PPV) and negative (NPV)] of electrodiagnostic findings for carpal tunnel syndrome (CTS) based on age, gender, and diabetes mellitus (DM) were not reported.

METHODS

In a retrospective study, we described the latency difference values and DA of comparative latency studies COLS [median to ulnar through palmar difference (palmdiff) and ring difference study (ringdiff), median to radial through thumb difference study (thumbdiff), and combined sensory index (CSI)] among non-CTS and CTS groups based on age, DM, and gender.

RESULTS

We included 632 patients (228 without CTS and 404 with CTS). For PPV > 90% and NPV > 50%, the best cut-offs among patients without DM, were 0.5ms, 0.8-1 ms, 1.4 ms, and 2 ms for palmdiff, thumbdiff, CSI (age < 60 years), and CSI (age > 60 years), respectively. The best cut-offs among patients with DM were 0.5 ms, 1.2 ms, 0.8 ms, 1.0-1.2 ms, 1.8 ms, 1-1.2 ms, 3.0 ms, and 3.5 ms for palmdiff (age < 50 years), palmdiff (age > 50 years), thumbdiff (age < 40 years), thumbdiff (age 40-59 years), thumbdiff (age > 60 years), CSI (age < 50 years), CSI (age 50-59 years), and CSI (age > 60 years), respectively.

CONCLUSION

The cut-off values of COLS to confirm CTS and their DA were different according to age and DM.

Understanding the Mechanosensitivity of the Median Nerve in Pre-Surgical Carpal Tunnel Syndrome Patients: A Correlational Study

(1) Background: Neurodynamic tests are recommended for the diagnosis of entrapment neuropathies such as carpal tunnel syndrome (CTS). However, their association with clinical variables in severe patients or patients with associated comorbidities is poorly documented. This study aims to analyze the association between the mechanosensitivity of the median nerve and symptoms, function and psycho-social variables in moderate and severe carpal tunnel syndrome patients with comorbidities; (2) Methods: Correlational study. In total, 42 pre-surgical patients (24 females; 59.1 ± 12.7 years) included in the Spanish Public Healthcare System with an electrodiagnostic of CTS were selected. Sociodemographic variables and clinical features (symptoms, function, sensitivity and quality of life evaluated with the 36-item Short Form Survey (SF-36) and the Medical Outcomes Study Sleep Scale (MOS-sleep) were recorded. Upper Limb Neurodynamic Test 1 was used to evaluate neural mechanosensitivity; (3) Results: The 81% had a severe CTS and 78.6% had some comorbidity. The average time from the first medical visit to the surgeon's visit was 365.5 days. Median nerve mechanosensitivity correlated weakly with the SF-36 subscale, General Health, (Spearman's rho = 0.367) and MOS sleep scale, Awaken Short of Breath or with headache dimension (Spearman's rho = -0.353) and moderately with SF-36 subscale, Social Functioning (Spearman's rho = 0.553); (4) Conclusions: No associations were observed for median nerve mechanosensitivity, except for quality of life and sleep. Both social determinants and clinical variables should be considered when examining and treating these patients.

Updates in diagnostic tools for diagnosing nerve injury and compressions

Predicting prognosis after nerve injury and compression can be challenging, even for the experienced clinician. Although thorough clinical assessment can aid diagnosis, we cannot always be precise about long-term functional recovery of either motor or sensory nerves. To evaluate the severity of nerve injury, surgical exploration remains the gold standard, particularly after iatrogenic injury and major nerve injury from trauma, such as brachial plexus injury. Recently, advances in imaging techniques (ultrasound, magnetic resonance imaging [MRI] and MR neurography) along with multimodality assessment, including electrodiagnostic testing, have allowed us to have a better preoperative understanding of nerve continuity and prediction of nerve health and possible recovery. This article outlines the current and potential roles for clinical assessment, exploratory surgery, electrodiagnostic testing ultrasound and MRI in entrapment neuropathies, inflammatory neuritis and trauma. Emphasis is placed on those modalities that are improving in diagnostic accuracy of nerve assessment before any surgical intervention.

Carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is the most common nerve entrapment disorder worldwide. The epidemiology and risk factors, including family burden, for developing CTS are multi-factorial. Despite much research, its intricate pathophysiological mechanism(s) are not fully understood. An underlying subclinical neuropathy may indicate an increased susceptibility to developing CTS. Although surgery is often performed for CTS, clear international guidelines to indicate when to perform non-surgical or surgical treatment, based on stage and severity of CTS, remain to be elucidated. Neurophysiological examination, using electrophysiology or ultrasonography, performed in certain circumstances, should correlate with the history and findings in clinical examination of the person with CTS. History and clinical examination are particularly relevant globally owing to lack of other equipment. Various instruments are used to assess CTS and treatment outcomes as well as the effect of the disorder on quality of life. The surgical treatment options of CTS - open or endoscopic - offer an effective solution to mitigate functional impairments and pain. However, there are risks of post-operative persistent or recurrent symptoms, requiring meticulous diagnostic re-evaluation before any additional surgery. Health-care professionals should have increased awareness about CTS and all its implications. Future considerations of CTS include use of linked national registries to understand risk factors, explore possible screening methods, and evaluate diagnosis and treatment with a broader perspective beyond surgery, including psychological well-being.

Comparison of local versus intramuscular steroid injection in patients with carpal tunnel syndrome: A prospective open label randomized clinical trial

AIM

This study compared the efficacy and safety of local corticosteroid injection (LCI) vs intramuscular (IM) corticosteroid injection in mild to moderate carpal tunnel syndrome (CTS).

METHODS

This is an open labeled, randomized controlled trial conducted during December 2021 to August 2023. Eighty-six patients with CTS were randomized in 1:1 ratio to receive either single 40 mg methylprednisolone (MP) injection at the wrist (LCI arm), or single 40 mg MP intramuscular injection (IM arm) in the deltoid. Primary outcome was absolute Symptom Severity Scale (SSS) at 3 months. Secondary outcomes were SSS score at 1-month, Functional Status Scale (FSS) score at 1 and 3 months, and recurrence at 3 months and injection site pain assessed on visual analog (VAS) scale.

RESULTS

Median age was 45 (range 22 - 80) years, and 86 % were females. Baseline characteristics were comparable between groups. Mean SSS score at 3 months was similar in two arms (1.72 ± 0.71 vs 2.0 ± 0.93) with mean difference (MD) -0.03 (-0.31 to 0.25, p = 0.83) after adjusting for baseline SSS scores. LCI, however, resulted in significantly better SSS (1.48 ± 0.51 vs 1.88 ± 0.69, adjusted p = 0.04), and FSS scores (1.57 ± 0.44 vs 1.80 ± 0.66, adjusted p = 0.03) at 1 month compared to IM arm. Response rate (67.4 % vs 55.8 %; p = 0.30) and recurrence rate (17.1 % vs 22.6 %, p = 0.74) at 3 months were similar. Injection site pain was severe in LCI arm[median 5 (range 3 - 8) vs median 3 (range 2 - 6)].

CONCLUSIONS

In patients with mild to moderate CTS, LCI resulted in better improvement in the BCTQ scores at 1 month compared to IM steroid. However, 3-month's outcome was similar. Intramuscular steroid injection was better tolerated.

A revised approach for electrodiagnosis-based severity classification in carpal tunnel syndrome

BACKGROUND

An electrodiagnostic evaluation is conducted to diagnose carpal tunnel syndrome (CTS) and evaluate its severity.

OBJECTIVE

This study proposes a revised approach for classifying the severity of electrophysiological findings for patients with CTS.

METHODS

This retrospective cross-sectional study included patients with CTS confirmed through electrodiagnostic evaluations. Based on the Stevens' classification, the patients were divided into three groups (mild/moderate/severe). A new intermediate group was defined to identify patients with normal motor nerve conduction studies and abnormal electromyographic results. CTS pain was evaluated using a numeric rate scale. Physical examinations and sonographic evaluation were performed to detect anatomical abnormalities.

RESULTS

Overall, 1,069 CTS hands of 850 CTS patients were included. The mean age was 57.9 ± 10.8 years, and 336 (39.5%) were men. There were 522 (48.8%) mild cases; 281 (26.3%) moderate cases; and 266 (24.9%) severe cases. In the severe group, 49 cases were reclassified into the intermediate group. The median cross-sectional area in the intermediate group significantly differed from that in the severe group. However, the pain score significantly differed from that of the moderate group.

CONCLUSION

The intermediate CTS group showed clinical features that were intermediate to those of the moderate and severe CTS groups.

Neuromuscular manifestations of wild type transthyretin amyloidosis: a review and single center's experience

Transthyretin amyloidosis (ATTR) is a condition defined by accumulation of insoluble transthyretin amyloid deposits in multiple organs, especially in the peripheral nerve and heart muscle. ATTR may result from transthyretin mutations (variant ATTR or ATTRv) or may occur with normal transthyretin genotype (wild type ATTR or ATTRwt). ATTRwt was previously known as "senile amyloidosis" and causes cardiomyopathy which may lead to heart failure with a preserved ejection fraction, affecting predominantly elderly men. The exact prevalence of ATTRwt in the general population remains unclear, but its occurrence may be underestimated in women. It was observed that a proportion of ATTRwt cardiomyopathy patients may develop slowly progressing neuropathy that is milder and indolent in comparison with typical progressive neuropathy associated with ATTRv. Furthermore, the causality of neuropathy is often uncertain in patients with ATTRwt. Neuropathy symptoms, including distal sensory loss, unsteadiness and (neuropathic) pain are common in elderly patients with multiple potential causes, and as ATTRwt patients are typically older, relatively high prevalence of peripheral neuropathy is expected with frequent comorbidities. Relatively high prevalence of ATTRwt in elderly population contrasts few documented cases of neuropathy caused by ATTRwt, and there is uncertainty whether ATTRwt neuropathy is an infrequent occurrence or a significant manifestation of multisystemic ATTRwt. We review neurologic and musculoskeletal manifestations of ATTRwt and present clinical features of a single center cohort of ATTRwt patients with suspected peripheral neuropathy.

Safety and Efficacy of Ultrasound-Guided Perineural Hydrodissection as a Minimally Invasive Treatment in Carpal Tunnel Syndrome: A Systematic Review

Ultrasound-guided perineural hydrodissection (HD) is a novel technique that has been found to be effective in providing mechanical release of perineural adhesions and decompression of the nerve, reducing inflammation and edema and restoring its physiological function. It has a significant impact on chronic neuropathic pain (20 ± 4 weeks with VAS < 5 or VAS diminished by 2 points after the procedure). Carpal tunnel syndrome (CTS) is a common entrapment mononeuropathy, and its distribution is typically innervated by the median nerve. Patients with mild or moderate CTS may benefit from nonsurgical treatments or conservative therapies. This review was conducted following the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement guidelines. Four investigators assessed each title, abstract, and full-text article for eligibility, with disagreements being resolved by consensus with two experienced investigators. The qualitative assessment of the studies was carried out using the modified Oxford quality scoring system, also known as the modified Jadad score. Furthermore, risk of possible biases was assessed using the Cochrane collaboration tool. The results of this review suggest that US-guided HD is an innovative, effective, well-tolerated, and safe technique (11 out of 923 patients had collateral or side effects after the procedure). However, further studies comparing all drugs and with a larger sample population are required to determine the most effective substance.

Transthyretin amyloid deposition in ligamentum flavum (LF) is significantly correlated with LF and epidural fat hypertrophy in patients with lumbar spinal stenosis

Lumbar spinal stenosis (LSS) is a degenerative disease characterized by intermittent claudication and numbness in the lower extremities. These symptoms are caused by the compression of nerve tissue in the lumbar spinal canal. Ligamentum flavum (LF) hypertrophy and spinal epidural lipomatosis in the spinal canal are known to contribute to stenosis of the spinal canal: however, detailed mechanisms underlying LSS are still not fully understood. Here, we show that surgically harvested LFs from LSS patients exhibited significantly increased thickness when transthyretin (TTR), the protein responsible for amyloidosis, was deposited in LFs, compared to those without TTR deposition. Multiple regression analysis, which considered age and BMI, revealed a significant association between LF hypertrophy and TTR deposition in LFs. Moreover, TTR deposition in LF was also significantly correlated with epidural fat (EF) thickness based on multiple regression analyses. Mesenchymal cell differentiation into adipocytes was significantly stimulated by TTR in vitro. These results suggest that TTR deposition in LFs is significantly associated with increased LF hypertrophy and EF thickness, and that TTR promotes adipogenesis of mesenchymal cells. Therapeutic agents to prevent TTR deposition in tissues are currently available or under development, and targeting TTR could be a potential therapeutic approach to inhibit LSS development and progression.

Effects of high-intensity laser therapy on pain, functional status, hand grip strength, and median nerve cross-sectional area by ultrasonography in patients with carpal tunnel syndrome

The aim of this study was to evaluate the effects of high intensity laser therapy (HILT) on pain, functional status, hand grip strength, and median nerve cross-sectional area by ultrasonography in patients with carpal tunnel syndrome. Sixty patients who were diagnosed with carpal tunnel syndrome were included in the study. The patients observed during the research were randomly divided into two groups with 30 patients in each group. Splint+ exercise and HILT (pulsed mode with a power of 8.0 W and energy density of 8 J/cm2 for 1.40 minutes for every 25 cm2, continuous mode with a power of 3.0 W and energy density of 80 J/cm2 for 11 minutes for each 25 cm2; total 10 sessions 5 days a week) were applied for 2 weeks for the first group, and splint+exercise and sham laser treatment were applied for 2 weeks for the second group. Randomization was undertaken with the assistance of a computer-generated random number table before beginning the treatment processes. The patients were evaluated with the determined scales before the treatment, at the end of the treatment, and at the 3rd month. Hydraulic hand dynamometer was used to measure hand grip strength, visual analog scale (VAS) for pain, Boston CTS Questionnaire to assess function, and ultrasonography to measure median nerve cross-sectional area. The impact of time on the change in VAS levels was found to be of statistical significance within each group of patients (p<0.001), but between-group comparisons did not yield significant results (p<0.454). The effects of time on variations in Boston CTS Questionnaire scores were found to have been of statistical significance for both groups (p<0.001), but significance was not subsequently observed when the results of the two groups were compared on a between-group basis (p=0.226 and p=0.973 for the FSS and SSS, respectively). While time had a statistically significant effect on the change in hand grip strength for both groups (p=0.000), between-group comparisons statistical significance finding in favor of HILT was found in the early period (p=0.012). The time-group association patterns of the groups showed significant difference (p=0.025). While time had a statistically significant effect on the changes in the median cross-sectional areas of the nerve for the patients of both treatment groups (p<0.001), between-group comparisons yielded no findings of statistical significance (p=0.438). The time-group relationship patterns of the groups were found to reflect statistical significance (p=0.001). In conclusion, the results of the research presented here have confirmed that hand grip strength may increase and the median nerve's cross-sectional area may decrease upon the application of high-intensity laser for individuals experiencing CTS. However, this effect was demonstrated here only in the short-term and the evidence was not maintained through the course of follow-up of a longer duration.

Temporal Changes in Electrophysiological Parameters in Untreated Patients With Carpal Tunnel Syndrome

INTRODUCTION

Carpal tunnel syndrome (CTS) is a common entrapment neuropathy worldwide. This study aimed to investigate the temporal changes in electrophysiological parameters in untreated patients with CTS.

METHODS

Patients were recruited among those with the symptoms of CTS who were referred to the electrophysiology laboratory of Niğde Ömer Halisdemir University Bor Physical Therapy and Rehabilitation Hospital in Niğde, Turkey. Forty-nine patients (78 hands) who had not received any sort of treatment for CTS and had prior electrophysiological examination postive for CTS were included. Laboratory records were reviewed retrospectively. Recent electrophysiological parameters of the patients were compared to their prior examinations using Wilcoxon signed-rank test and sign test was used to compare the change in the electrophysiological severity of the study hands between two examinations. One-way analysis of variance (ANOVA) was used to compare individual parameters of the median NCS among electrophysiological change groups (improved, deteriorated, and same).

RESULTS

The mean age was 50 ± 11 years, and 43 (88%) patients were female. The mean duration of time between the two electrophysiological examinations was 37 ± 20 months. Median sensory peak latency and median motor distal latency increased significantly in the second evaluation (p=0.005 and p=0.004, respectively). Median sensory conduction velocity decreased in the second examination (p=0.002). However, CTS severity determined electrophysiologically did not differ significantly in the two examinations (p=0.286).

CONCLUSION

Although there was a deterioration in electrophysiological parameters during a mean follow-up period of 37 months, the electrophysiological severity of the patients did not worsen.

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.

Use of Iontophoresis with Corticosteroid in Carpal Tunnel Syndrome: Systematic Review and Meta-Analysis

BACKGROUND

Carpal tunnel syndrome is a neuropathy that affects the median nerve. The aim of this review is to synthesize the evidence and perform a meta-analysis on the effects of iontophoresis in people with carpal tunnel syndrome.

METHODS

The search was carried out using PubMed, Web of Science, Scopus, CINHAL Complete, Physiotherapy Evidence Database, and SciELO. The methodological quality was evaluated using PEDro. A standardized or mean difference meta-analysis (Hedge's g) using a random-effects model was calculated.

RESULTS

Seven randomized clinical trials using iontophoresis for electrophysiological, pain, and functional outcomes were included. The mean of PEDro was 7/10. No statistical differences were obtained for the median sensory nerve conduction velocity (SMD = -0.89; p = 0.27) or latency (SMD = -0.04; p = 0.81), motor nerve conduction velocity (SMD = -0.04; p = 0.88) or latency (SMD = -0.01; p = 0.78), pain intensity (MD = 0.34; p = 0.59), handgrip strength (MD = -0.97; p = 0.09), or pinch strength (SMD = -2.05; p = 0.06). Iontophoresis only seemed to be superior in sensory amplitude (SMD = 0.53; p = 0.01).

CONCLUSIONS

Iontophoresis did not obtain an enhanced improvement compared to other interventions, but no clear recommendations could be made due to the limited number of included studies and the heterogeneity found in the assessment and intervention protocols. Further research is needed to draw sound conclusions.