Electrosonodiagnosis in Carpal Tunnel Syndrome: A Proposed Diagnostic Algorithm Based on an Analytic Literature Review

Acroparesthesias: An Overview

Acroparesthesia is a symptom characterized by a subjective sensation, such as numbness, tingling, prickling, and reduced sensation, affecting the extremities (fingers and toes). Despite its frequency, data regarding its diagnostic approach and management are scarce. The etiological diagnosis of acroparesthesia is sometimes challenging since it can be due to abnormality anywhere along the sensory pathway from the peripheral nervous system to the cerebral cortex. Acroparesthesia can reveal several diseases. It can be associated with rheumatic complaints such as arthritis or myalgia. Further cautions are required when paresthesia is acute (within days) in onset, rapidly progressive, severe, asymmetric, proximal, multifocal, or associated with predominant motor signs (limb weakness) or severe dysautonomia. Acroparesthesia may reveal Guillain-Barré syndrome or vasculitis, requiring rapid management. Acroparesthesia is a predominant symptom of polyneuropathy, typically distal and symmetric, often due to diabetes. However, it can occur in other diseases such as vitamin B12 deficiency, monoclonal gammopathy of undetermined significance, or Fabry's disease. Mononeuropathy, mainly carpal tunnel syndrome, remains the most common cause of acroparesthesia. Ultrasonography contributes to the diagnosis of nerve entrapment neuropathy by showing nerve enlargement, hypoechogenic nerve, and intraneural vascularity. Besides, it can reveal its cause, such as space-occupying lesions, anatomical nerve variations, or anomalous muscle. Ultrasonography is also helpful for entrapment neuropathy treatment, such as ultrasound-guided steroid injection or carpal tunnel release. The management of acroparesthesia depends on its causes. This article aimed to review and summarize current knowledge on acroparesthesia and its causes. We also propose an algorithm for the management of acroparesthesia.

The role of ultrasound in determining the presence and severity of carpal tunnel syndrome in diabetic patients

Carpal tunnel syndrome (CTS) is seen in 5% of the population and 14%-30% in diabetics. Although electrophysiological tests are used as the gold standard method in the diagnosis, alternative methods are being studying. We aimed to investigate whether the measurement of median nerve cross-sectional area (CSA) by ultrasound is associated with the presence and severity of CTS. This prospective, cross-sectional observational study includes 128 randomly selected T2DM patients. Electrodiagnostic study was performed for all patients to diagnose CTS. Median nerve CSA were measured with ultrasound examination. The severity of the CTS was determined by Padua method. Among 128 diabetes mellitus (DM) patients, 54 (28%) had CTS and 53 (41%) had diabetic peripheral polyneuropathy. The mean duration of DM was 11.55 years. Median nerve CSAs of the patients were significantly higher in patients with CTS (CTS (-): 10.47 ± 2.67 vs CTS: (+) 12.37 ± 3.17; p < 0.001). Median nerve CSA cutoff value of >10 mm2 predicts the diagnosis of CTS. However, minimal, mild, and moderate CTS groups had similar CSA according to Padua classification (p > 0.05 for all). CSA measurement with ultrasonography can be used as an effective method in diagnosing severe CTS disease. However, median nerve CSA values should not be used to reveal the severity of CTS, in order not to miss the demonstration of minimal, mild, and moderate groups, as well as being an indicator of only the severe CTS group.

Value of ultrasonography in the diagnosis of carpal tunnel syndrome-a new ultrasonographic index in carpal tunnel syndrome diagnosis: A clinical study

We analyze the effectiveness of ultrasonography in diagnosing carpal tunnel syndrome (CTS) and propose the use of sonographic index of median nerve (MN) in carpal tunnel (SIMNCT) in a diagnostic algorithm and in establishing a scale of severity.We studied a group of 344 patients with CTS symptoms, examining them by ultrasound. We measured in all patients, on the affected hand: the size of the cross-sectional area of the MN at carpal tunnel (CT) inlet and outlet, nerve morphology at passage through CT, the vertical thickness of the MN entering into the CT - G1, the lowest vertical thickness into the CT or leaving the CT - G2, the thickness of the MN in the transversal plane as entering in the CT - L. Normal values were considered the similar measurements taken on the healthy hand and we established as normal SIMNCT = 16%. We proposed the formula SIMNCT = 100% (1-G2/G1) in order to calculate the index.Statistics show a significant sensitivity of SIMNCT (P < .0001) compared with cross-sectional area (CSA) and flattening ratio in the diagnosis of CTS. Analyzing the SIMNCT developed by us, we demonstrated a sensitivity of 94.81% and a specificity of 99.66% in CTS diagnosis. Thereby, we propose a CTS severity classification: normal = 16%, mild = 16-19%, moderate = 19% to 28%, severe = 28% to 50%, very severe > 50%.Ultrasonography is an effective method of studying the morphology of the tunnel and compressed nerve at various CTS stages and determining the cause of compression. The SIMNCT is a valuable and practical indicator and it can be used in the CTS diagnosis.

Palmaris Longus Tendinopathy Diagnosed With Ultrasound: A Case Report

This patient is a 52-year-old woman who was referred to the electrodiagnostic (EDX) laboratory for evaluation of pain and paresthesias of the left upper limb. The results of the EDX study were normal. However, ultrasound revealed tendinopathy of the palmaris longus tendon, manifested by increased hypoechogenicity, caliber, and tenderness in response to sonopalpation compared to the right side. To the authors' knowledge there are no reported cases of palmaris longus tendinopathy diagnosed with ultrasound. This case supports the use of point-of-care ultrasound to explore other possible causes of pathology in patients with paresthesias in the context of normal findings on an EDX study. LEVEL OF EVIDENCE: V.

Ultrasonography Predictive Factors of Response to Local Steroid Injection in Patients with Carpal Tunnel Syndrome

Background:

The aim of this study is to determine the predictive value of ultrasonography for results of local steroid injection in patients with carpal tunnel syndrome (CTS).

Materials and Methods:

This prospective cohort study was conducted during a 1-year period in outpatient clinics of rehabilitation and physical medicine including 35 patients with moderate and severe CTS who receive ultrasonography-guided local steroid injection. The Boston self-assessment questionnaire and electrodiagnosis parameters were recorded at baseline, 1 month, and 3 months after therapy. We also recorded the baseline ultrasonography parameters to determine the predictors of outcome.

Results:

The sensory severity score and functional status scale along with electrodiagnosis parameters decreased significantly at 1 month (P < 0.001) and remained unchanged after 3 months. Volar bulging was negatively associated with sensory nerve action potential latency (r = −0.392; P = 0.020). Cross-sectional area (CSA) of maximal swelling (MS; r = 0.409; P = 0.015), CSA at 2-cm of MS (r = 0.563; P < 0.001), and CSA at 12-cm of MS (r = 0.521; P = 0.001) correlated positively with compound muscle action potential (CMAP) amplitude while maximal swelling/12-cm MS ratio (r = −0.439; P = 0.008) and maximal swelling/2-cm MS ratio (r = −0.342; P = 0.045) correlated negatively. CSA at 12-cm of MS also correlated positively with CMAP amplitude nerve conduction velocity (r = 0.436; P = 0.010).

Conclusion:

Volar bulging, CSA of maximal swelling, CSA of MS at 2-cm, and CSA of MS at 12-cm are among the ultrasonographic predictors of response to local steroid injection in patients with CTS.

Anatomic Relationship Between the Hook of the Hamate and the Distal Transverse Carpal Ligament: Implications for Ultrasound-Guided Carpal Tunnel Release

OBJECTIVE

During ultrasound-guided carpal tunnel release, osseous landmarks may supplement direct visualization of the distal transverse carpal ligament (dTCL) to ensure a complete release. The purpose of this study was to determine the relationship between the apex of the hook of the hamate (aHH) and the dTCL within the transverse safe zone (TSZ) of the carpal tunnel.

DESIGN

Twenty unembalmed cadaveric specimens were dissected to determine the aHH-dTCL distance and the aHH-SPA distance (the distance between the aHH and the superficial palmar arch) at the ulnar and radial limits of the TSZ (the distance between the hook of the hamate or ulnar artery to the median nerve).

RESULTS

The aHH-dTCL distance averaged 11-12 mm across the TSZ (maximum, 18.2 mm), whereas the aHH-SPA distance was significantly greater on the radial side of the TSZ compared with the ulnar side (22.6 ± 3.6 mm vs. 14.0 ± 4.0 mm).

CONCLUSIONS

The dTCL lies approximately 11-12 mm distal to the aHH across the TSZ, with an upper limit of 18.2 mm. Along with direct sonographic visualization of the dTCL, the aHH can be used with other osseous landmarks to estimate the position of the dTCL during ultrasound-guided carpal tunnel release.