الفهرس 
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Abstract
Carpal tunnel syndrome (CTS) was first reported in 1854 by Paget as a posttraumatic entrapment. neuropathy at the wrist joint. In 1966, Phalen popularized the far more common idiopathic CTS, and increased the recognition of this syndrome.
CTS is one of the most common peripheral mono-neuropathies which occurs due to localized compression of the median nerve (MN) in the CT and is considered a major cause of occupational disability. With the introduction of new technology including computers, mobile phones and tablets, its prevalence increased significantly, and it has been reported to represent up to 90% of all entrapment neuropathies.
There are many potential causes for CTS, such as malunion after distal radius fracture, rheumatic synovitis, amyloidosis, diabetes, pregnancy, or soft tissue tumor. But most of the time, CTS is idiopathic. Traditionally, the diagnosis of carpal tunnel syndrome is established by the history, clinical symptoms, and physical examination.
Clinical findings include numbness and impaired sensation of the innervation area of median nerve, brachialgia, paraesthetica, nocturna, thenar muscle atrophy, sometimes swelling of the palmar side of the wrist, and the results of provocative tests such as Phalen’s maneuver or Tinel’s sign. Early diagnosis is essential to alleviate permanent nerve damage and functional disability.
Electrophysiological (EP) tests are useful when the diagnosis is unclear, there are confounding neurological disorders such as radiculopathy or polyneuropathy, or to quantify disease severity. However, they have a false-negative rate of 16%–34% due to variations between individuals and in technical factors, such as age, skin temperature, the recording-electrode location, and the distance between the reference and recording electrodes invasiveness as Earlier reports showed that NCS can be normal in early cases. Furthermore, NCS were reported as not sensitive to change or management, hence, a poor predictor of treatment outcomes has led to a search for other, less invasive, and more convenient diagnostic option.
High resolution ultrasound (HRUS) has emerged as a feasible, simple, relatively low-cost, rapid, accurate, and noninvasive imaging method for evaluating the median nerve in the carpal tunnel, it also can be used to examine tissues in both static and dynamic states in real time.
Since then, several studies have been conducted to evaluate the role of ultrasound in diagnosing CTS and its advantages and disadvantages compared to nerve conduction studies (NCS). These studies have attempted to define the optimal criteria by which ultrasound measurements can be used to define CTS.
Cross sectional area of the median nerve was the most commonly investigated criteria. However, there is still much debate with regards to the level within the carpal tunnel that this measurement should be taken and furthermore what constitutes as abnormal value.
Advances in ultrasound (US) technology have made it possible to achieve a spatial resolution good enough to depict peripheral nerves clearly. Recently, there has been growing interest in the use of US for the diagnosis of CTS However, there is no consensus of opinion on the optimal criteria for the diagnosis of CTS by US and, therefore, the role of US in the management of these patients. The purpose of this study was to evaluate the utility of high-resolution ultrasonography in CTS diagnosis through evaluating different ultrasonographic diagnostic criteria in patients with clinical and electrodiagnostic evidence of CTS.
This prospective study was conducted on one hundred subjects that were categorized into two groups:
• Cases group: 30 cases (those with symptoms of CTS) with 50 wrists.
• Control group: 30 healthy controls (those with no symptoms of CTS) with 50 wrists.
All patients were subjected to clinical examinations, nerve conduction studies, and high resolution US.
Summary of our results:
• There was no statistically significant difference between the cases and control groups regarding age and gender.
• There was no statistically significant difference between the two groups as regards CSA1 (forearm), but CSA2 (inlet), CSA3 (outlet), Mean CSA [(2+3) /2] Δ CSA (2-3), R-CSA (mean CSA/CSA1), median nerve flattening ratio, palmar bowing of the flexor retinaculum, and PDS (color score) vascularity were statistically significant higher in cases than controls.
• Regarding NCS severity, cases were distributed into 13(26%) mild, 27(54%) moderate, and 10(20%) severe.
• Regarding patients’ sonographic parameters according to CTS severity, there was no statistically significant difference between the groups as regards CSA1 (forearm), but CSA2 (inlet), CSA3 (outlet), mean CSA [(2+3) /2] Δ CSA (2-3), R-CSA (mean CSA/CSA1), median nerve flattening ratio, palmar bowing of the flexor retinaculum, and PDS (color score) vascularity were statistically significant increasing as severity increasing.
• CSA2 (inlet), CSA3 (outlet), Mean CSA [(2+3) /2] Δ CSA (2-3), R-CSA (mean CSA/CSA1), median nerve flattening ratio, palmar bowing of the flexor retinaculum, and PDS (color score) vascularity are sensitive sonographic parameters to predict CTS at cut off ≥12, ≥10, ≥2, ≥11.5, ≥1.4, ≥1.7, ≥2.7, and ≥1 receptively with high sensitivity and specificity and significant P-value.
Conclusion
High resolution ultrasound is a valid and accurate diagnostic modality in carpal tunnel syndrome and correlated to CTS severity. CSA2 (inlet), CSA3 (outlet), mean CSA, Δ CSA, R-CSA, median nerve flattening ratio, palmar bowing of the flexor retinaculum, and PDS (color score) vascularity were sensitive sonographic parameters to predict CTS with high sensitivity and specificity.
Recommendations
• Larger cohorts with a longitudinal study design are needed to determine how US can be used together to improve the diagnosis and treatment of CTS.
• High resolution ultrasound is a valid and accurate diagnostic modality in carpal tunnel syndrome and correlated to CTS severity.
• Studies should stress on the follow up of patients, on CTS treatment, which modality is more valuable in that respect and how to diminish risk factors in such patients.
• More studies should stress recurrent cases of idiopathic CTS either after medical and physical treatment or after surgical release.
• Patients with a history of previous wrist surgery, fracture or traumatic nerve injury should be recommended.
Limitations
• The main drawback is the relatively low number of cases and controls.
• Ultrasonography is unlikely to solve all the diagnostic dilemmas in CTS and its cost-effectiveness and definitive role in the management of patients with CTS need to be further evaluated.
• Ultrasonography is not mandatory diagnostic tool in patients with classic symptoms and/or characteristic abnormalities on the electrophysiological examination.
• Ultrasonography is a subjective procedure and needed experienced radiologist to diagnosis CTS.