Ultrasound Findings in Less Frequent Causes of Carpal Tunnel Syndrome

Abstract

The most common etiology of carpal tunnel syndrome (CTS) is idiopathic. However, secondary causes of CTS should be considered when symptoms are unilateral, or electrodiagnostic studies are discrepant with the clinical presentation. Imaging of the carpal tunnel should be performed when secondary causes of CTS are suspected. An ultrasound evaluation of the carpal tunnel can assess for pathologic changes of the median nerve, detect secondary causes of CTS, and aid in surgical planning.

Neuromuscular ultrasound findings in carpal tunnel syndrome with symptoms mainly in the nondominant hand

“…Several types of space‐occupying lesions within the carpal tunnel have been previously reported in case reports and series. These include but are not limited to occult ganglia, lipomas, calcified nodules, and tophi secondary to gout or calcium pyrophosphate deposition disease (CPPD) 3,9 . Although each finding is relatively rare, the ability to characterize the nature of these lesions by HRUS is helpful in planning treatment.…”

“…7 As tenosynovitis can occur from degeneration, infection, and inflammatory (rheumatological) conditions, its presence also markedly changes further evaluation and treatment. 9 Likewise, when HRUS identifies a mass lesion compressing the median nerve, surgical intervention to remove the mass and/or release the pressure is indicated, obviating the use of steroid injections and other conservative measures. Several types of spaceoccupying lesions within the carpal tunnel have been previously…”

“…These include but are not limited to occult ganglia, lipomas, calcified nodules, and tophi secondary to gout or calcium pyrophosphate deposition disease (CPPD). 3,9 Although each finding is relatively rare, the ability to characterize the nature of these lesions by HRUS is helpful in planning treatment. A variety of mass lesions were also seen in our cohort, almost twice as often in patients with Atypical CTS.…”

“…Criteria for diagnosis was based on the AANEM Practice Parameter on Electrodiagnostic Studies in CTS and AANEM Evidence-based Guideline: Neuromuscular Ultrasound for the Diagnosis of CTS. 8,9 Cross-sectional area (CSA) on HRUS of median nerve at the wrist ≥13 mm 2 with a wrist-to-forearm ratio ≥ 1.5 on HRUS were diagnostic of median neuropathy at the wrist. Severity of CTS was determined by nerve conduction studies: "mild," if the median sensory or mixed (palmar) distal latency was prolonged with or without sensory amplitude reduction; "moderate," if the median motor distal latency was also prolonged; "severe," if the median sensory response was absent or the median thenar compound muscle action potential amplitude was reduced.…”

Artifacts in Musculoskeletal Ultrasonography: From Physics to Clinics

“…Owing to advantages like portability, real-time assessment [ 1 , 2 ], and absence of radiation, high-resolution ultrasound (US) has emerged as the most useful imaging tool [ 3 , 4 ] in the diagnosis [ 5 , 6 , 7 ] and guided treatment [ 8 , 9 ] of musculoskeletal disorders. In addition to getting acquainted with scanning skills and sonoanatomy [ 10 , 11 ], medical professionals should also be aware of basic US physics and avoid or tackle the artifacts occurring during imaging.…”