Diagnostic meta-analysis of the efficacy of ultrasonography for diagnosing carpal tunnel syndrome: A comparison between Asian and non-Asian populations

BACKGROUND

Ultrasonography is used to diagnose carpal tunnel syndrome (CTS) according to various criteria. This diagnostic meta-analysis aimed to evaluate the efficacy of ultrasonography for diagnosing CTS, focusing on the cross-sectional area (CSA) of the median nerve (MN) at the inlet of the carpal tunnel and regional variations in diagnostic thresholds between Asian and non-Asian populations.

METHODS

A comprehensive literature search was conducted using PubMed, Embase, and the Cochrane Library. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Patient demographic data, diagnostic "gold standards", CSA cutoff values, and diagnostic results were extracted. Meta-analysis was performed to determine the sensitivity, specificity, and optimal CSA cutoff values.

RESULTS

For the 25 included studies, a combined sensitivity of 88% and specificity of 84% for CSA measurements at the carpal tunnel inlet were obtained. The Asian group had a sensitivity of 84% and specificity of 86%, while the non-Asian group had a sensitivity of 91% and specificity of 82%. The mean CSA in the Asian group was significantly lower than that in the non-Asian group (12.93 mm2 and 14.77 mm2, respectively; p = 0.042). For the Asian group, the summary receiver operating characteristic curve had an area under the curve (AUC) of 0.92 with an optimal cutoff of 10.5 mm2; for the non-Asian group, an AUC of 0.94 was obtained with a cutoff of 11.5 mm2.

CONCLUSION

Ultrasonography is a reliable diagnostic method for CTS, with distinct optimal cutoff values observed between Asian and non-Asian populations. Therefore, population-specific diagnostic criteria for CTS are recommended.

The Impact of Reference Standard on Diagnostic Testing Characteristics for Carpal Tunnel Syndrome: A Systematic Review

Lack of a reliable reference standard for carpal tunnel syndrome (CTS) diagnosis could impact the diagnostic test characteristics. This systematic review sought to evaluate differences in the accuracy of CTS diagnostic modalities based on the reference standard used.

Methods

A systematic review was performed following PRISMA guidelines to investigate diagnostic modalities used in CTS. A literature search of Embase, PubMed, and Cochrane Reviews was conducted for the years of 2010-2021 for primary data, and 113 studies met final inclusion criteria. Studies were stratified based on the reference standard utilized and diagnostic modality assessed, and the weighted means of the sensitivities and specificities were calculated.

Results

Thirty-five studies used clinical diagnosis alone as a reference standard, and 78 studies used electrodiagnostic study (EDS). The specificity for MRI and ultrasound (US) were substantially lower when EDS was used as the reference standard. MRI was the test most affected by the reference standard used, showing increased sensitivity when using EDS as the reference compared to clinical diagnosis (77.1% versus 60.9%) and decreased specificity (87.6% versus 99.2%). Regardless of the reference standard used, all tests had anticipated false-positive and/or false-negative rates of at least 10%.

Conclusions

Testing characteristics vary greatly based on the choice of reference standard, with the sensitivity of MRI most affected. Regardless of reference standard used, EDS, US, and MRI each had false-positive and/or false-negative rates too great to be appropriate for use as a screening examination.

Occupational hand and wrist disorders among forestry workers: An exposed-control study to investigate preventive strategies

BACKGROUND: In the arboriculture sector, some activities are still manually performed by forestry workers, which result consequently exposed to a high risk of developing muscle skeletal disorders. The Italian Compensation Authority reported an increase of work-related tendinopathies and carpal tunnel syndrome in loggers, but screening protocols are not available yet. OBJECTIVES: The objectives were: a) to evaluate the prevalence of tendinopathies and carpal tunnel syndrome in a sample of loggers and b) identify a sound screening approach. METHODS: 41 loggers and 41 paired control workers were recruited for a total of 164 hands. The protocol included 1) demographic data; 2) medical history; 3) identification of CTS symptoms through a questionnaire and a hand-chart; 4) upper limbs clinical examination; 5) Raynaud’s diseases questionnaire; 6) wrists ultrasound; 7) NCS of the distal median nerve. RESULTS: The prevalence of tendinopathies was statistically significant only in the non-dominant hand (75, 5% in the exposed group and 53, 6% in the non-exposed group). The prevalence of CTS was 32, 2% in the exposed group and 15, 5% in the non-exposed group. The questionnaire had a sensitivity of 56, 7% and a specificity of 75%. The hand-chart had a sensitivity of 30% and a specificity of 92%. The clinical examination had sensitivity of 30% and specificity of 80%. The ultrasound had a sensitivity of 70% and a specificity of 56%. CONCLUSIONS: Loggers are a population at risk of occupational hand and wrist disorders. The hand-chart could be considered, together with the questionnaire, as the best secondary prevention tool to diagnose CTS.

Median nerve ultrasonography examination correlates with electrodiagnostic studies for the diagnosis of moderate to severe carpal tunnel syndrome

OBJECTIVE

The aim of the study was to investigate the associations of cross-sectional area (CSA) of the median nerve measured by ultrasonography, the median to ulnar nerve ratio (MUR), the median to ulnar nerve difference (MUD) and the ratio of CSA of the median nerve to height squared (MHS) in relation to electrodiagnostic classification of moderate and severe carpal tunnel syndrome (CTS) and thus to identify patients suitable for surgical treatment.

MATERIALS AND METHODS

A prospective study was conducted in patients aged ≥ 18 years who underwent both median and ulnar nerve ultrasonography and electrodiagnostic studies (EDS). 124 wrists of 62 patients were examined. The patients' characteristics were acquired through a questionnaire. CTS was diagnosed using EDS and classified according to the guidelines of the Czech Republic Association of Electrodiagnostic Medicine. The CSA of the median nerve and of the ulnar nerve were measured at the carpal tunnel inlet.

RESULTS

Median nerve CSA at the tunnel inlet ≥ 12 mm² correlates with electrodiagnostic classification of moderate to severe carpal tunnel syndrome. At this cut-off value, the sensitivity of ultrasonography is 82.4%, its specificity is 87.7%, the positive predictive value is 82.4%, the negative predictive value is 87.7%. MUD, MUR and MHS perform worse than the median nerve CSA, as shown by their lower area under the receiver operating characteristic curve.

CONCLUSIONS

Ultrasound could help us indicate surgical treatment for CTS, especially in patients with clinical findings. Our results suggest a cut-off value of CSA at the tunnel inlet of ≥ 12mm².

"Physiological localization by sensory and motor inching studies and structural abnormalities detected by ultrasonographic changes in carpal tunnel syndrome"

OBJECTIVE

To study mild to moderate carpal tunnel syndrome (CTS), compare median nerve entrapment sites detected by electrophysiologic inching studies with ultrasonographic abnormalities of cross-sectional area (CSA), and correlate focal points of conduction delays detected by sensory and motor inching recorded from the third digit and second lumbrical muscle DESIGN: Analytic cross-sectional study SETTING: Department of Rehabilitation Medicine, King Chulalongkorn Memorial Hospital.

PARTICIPANTS

A total of 15 normal hands from 10 healthy participants and 40 hands with mild to moderate CTS from 29 participants were selected by convenience sampling.

INTERVENTIONS

Not applicable MAIN OUTCOME MEASURE: Correlation of electrophysiologic entrapment site localization by inching study with anatomical entrapment site detected by ultrasound (US).

RESULTS

In all 40 hands tested, a sharply localized latency was found to increase across a 1 cm segment, most commonly 2-3 cm distal to the distal wrist crease for both sensory and motor studies, showing a good match between the two with Pearson correlation coefficient value, r = 0.72. The US revealed a narrowing CSA of the median nerve at 1-2 cm distal to the distal wrist crease.

CONCLUSIONS

This study showed a high correlation for focal point conduction delay detected by sensory and motor nerve conduction study. Recording from the second lumbricalis facilitated motor inching along the straight course of the nerve instead of the arcuate recurrent branch innervating the abductor pollicis brevis, the muscle traditionally used. US examination also revealed a localized narrowing of the median nerve CSA at 1-2 cm distal to the distal wrist crease, a possible site for anatomical entrapment. The most enlarged CSA was seen at the distal wrist crease, a level corresponding to the inlet of the carpal tunnel.

THAI CLINICAL TRIALS REGISTRY NUMBER

TCTR20190605001.

Revision Peripheral Nerve Surgery of the Upper Extremity

Peripheral nerve injuries of the upper extremity can result from a wide array of etiologies, with the two most common being compression neuropathy and traumatic injuries. These types of injuries are common and can be psychologically, functionally, and financially devastating to the patient. A detailed preoperative evaluation is imperative for appropriate management. Traumatic injuries can typically be treated with local burial techniques, targeted muscle reinnervation, and regenerative peripheral nerve interfaces. Median nerve compression is frequently managed with complete release of the antebrachial fascia/transverse carpal ligament and/or use of flap coverage such as the hypothenar fat pad flap and local muscle flaps. Ulnar nerve compression is commonly managed via submuscular transposition, subcutaneous transposition, neurolysis, and nerve wrapping. In this review, we discuss the preoperative evaluation, surgical techniques, and advantages and disadvantages of each treatment modality for patients with compressive and traumatic upper extremity nerve injuries.