Ultrasound Findings in Less Frequent Causes of Carpal Tunnel Syndrome

Ultrasound Imaging and Guidance for Distal Peripheral Nerve Pathologies at the Wrist/Hand

Ultrasound has emerged as a highly valuable tool in imaging peripheral nerve lesions in the wrist region, particularly for common pathologies such as carpal tunnel and Guyon's canal syndromes. Extensive research has demonstrated nerve swelling proximal to the entrapment site, an unclear border, and flattening as features of nerve entrapments. However, there is a dearth of information regarding small or terminal nerves in the wrist and hand. This article aims to bridge this knowledge gap by providing a comprehensive overview concerning scanning techniques, pathology, and guided-injection methods for those nerve entrapments. The median nerve (main trunk, palmar cutaneous branch, and recurrent motor branch), ulnar nerve (main trunk, superficial branch, deep branch, palmar ulnar cutaneous branch, and dorsal ulnar cutaneous branch), superficial radial nerve, posterior interosseous nerve, palmar common/proper digital nerves, and dorsal common/proper digital nerves are elaborated in this review. A series of ultrasound images are used to illustrate these techniques in detail. Finally, sonographic findings complement electrodiagnostic studies, providing better insight into understanding the whole clinical scenario, while ultrasound-guided interventions are safe and effective for treating relevant nerve pathologies.

Ultrasound Imaging and Guidance in Common Wrist/Hand Pathologies

ABSTRACT

Wrist/hand pain is a prevalent musculoskeletal condition with a great spectrum of etiologies (varying from overuse injuries to soft tissue tumors). Although most of the anatomical structures are quite superficial and easily evaluated during physical examination, for several reasons, the use of ultrasound imaging and guidance has gained an intriguing and paramount concern in the prompt management of relevant patients. In this aspect, the present review aims to illustrate detailed cadaveric wrist/hand anatomy to shed light into better understanding the corresponding ultrasonographic examinations/interventions in carpal tunnel syndrome, trigger finger, de Quervain tenosynovitis, rhizarthrosis, and the radiocarpal joint arthritis. In addition, evidence from the literature supporting the rationale why ultrasound guidance is henceforth unconditional in musculoskeletal practice is also exemplified.

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

BACKGROUND

Carpal tunnel syndrome (CTS) may be associated with structural lesions or anatomical variations at the wrist, especially in patients whose symptoms are more severe in, or limited to, the nondominant hand. The aims of this study were to identify the type and frequency of structural abnormalities and anatomical variations, and to demonstrate the contribution of ultrasound in this subgroup of CTS patients.

METHODS

A retrospective chart review was performed on all patients referred to the electromyography laboratory who fulfilled the diagnostic criteria for CTS and who underwent neuromuscular ultrasound.

RESULTS

Of 114 CTS patients with symptoms mainly in nondominant hand, 51 (44.7%) had structural abnormalities or anatomical variations detected by ultrasound. In multivariable analysis, symptoms mainly in the nondominant hand and a body mass index (BMI) <30 kg/m² were the only independent variables significantly associated with structural findings, odds ratios 2.3 (P < .001) and 1.9 (P = .006), respectively.

CONCLUSIONS

Neuromuscular ultrasound, in addition to electrodiagnostic studies, should be considered in all CTS patients with symptoms more severe in nondominant hand as a significant number have abnormal structural abnormalities or anatomical variations that may be causative or change the therapeutic approach.

Artifacts in Musculoskeletal Ultrasonography: From Physics to Clinics

Ultrasound appears to be the most useful imaging tool in the diagnosis and guided treatment of musculoskeletal disorders. However, ultrasonography has been criticized for being user dependent. Therefore, medical professionals should be familiar with the basic principles of ultrasound imaging (e.g., physics and technical skills) to diminish artifacts and avoid misinterpretation. In this review, we focused on the physics of common artifacts, their clinical significance, and the ways to tackle them in daily practice during musculoskeletal imaging. In particular, artifacts pertaining to the focal zone, beam attenuation, path and side lobe of the beam, speed of the sound, and range ambiguity were described.

Artifacts in Musculoskeletal Ultrasonography: From Physics to Clinics

Ultrasound appears to be the most useful imaging tool in the diagnosis and guided treatment of musculoskeletal disorders. However, ultrasonography has been criticized for being user dependent. Therefore, medical professionals should be familiar with the basic principles of ultrasound imaging (e.g., physics and technical skills) to diminish artifacts and avoid misinterpretation. In this review, we focused on the physics of common artifacts, their clinical significance, and the ways to tackle them in daily practice during musculoskeletal imaging. In particular, artifacts pertaining to the focal zone, beam attenuation, path and side lobe of the beam, speed of the sound, and range ambiguity were described.