Carpal tunnel syndrome is the most frequent compression neuropathy with an incidence of one to three subjects per thousand. As specific anatomical variations might lead to unintended damage during surgical interventions, we present a review to elucidate the anatomical variability of the carpal tunnel region with important considerations for daily clinical practice: several variants of the median nerve branches in and around the transverse carpal ligament are typical and must - similarly to the variant courses of the median artery, which may be found eccentric ulnar to the median nerve - be taken into account in any interventional therapy at the carpal tunnel. Unintended interference in these structures might lead to heavy arterial bleeding and, in consequence, even underperfusion of segments of the median nerve or, if neural structures such as variant nerve branches are impaired or even cut, severe pain-syndromes with a profound impact on the quality of life. This knowledge is thus crucial for outcome- and safety-optimization of different surgical procedures at the volar aspect of the wrist and surgical therapy of the carpal tunnel syndrome e.g., US-guided carpal tunnel release, as injury might result in dysfunction and/or pain on wrist motion or direct impact in the region concerned. For most variations, anatomical and surgical descriptions vary, as official classifications are still lacking.
Aim: The purpose of this prospective ultrasound study was to document dorso-palmar (vertical) displacement of the median nerve in relation to the superficial flexor tendons at the level of the carpal tunnel. Furthermore, the gliding patterns of the median nerve were characterized. The presence of vertical gliding was intended to serve as an additional bio-kinematic parameter of median nerve movement, and will be referred to as a 'level change'.
Material and methods: In this study, a total of 32 healthy young individuals underwent dynamic high-resolution ultrasound examinations of both wrists. The neutral position, and maximum flexion and extension of the wrist had to be reached in active and passive movement. The gliding patterns were determined in relation to the superficial flexor tendons. When no vertical nerve gliding was observed, it was characterized as 'no level change'.
Results: The presence of a level change prevailed in the healthy young cohort and was observed in 84% (27/32) of individuals during wrist flexion. The following gliding pattern was distinctively the most common: gliding of the entire nerve in between the flexor tendons in active but not in passive movement of the right and left wrists (13/27; 48%). The extent of vertical displacement was found to be associated with the gliding pattern (Kruskal-Wallis test).
Conclusions: Movement in the carpal tunnel allows the median nerve to adapt to biomechanical stress. Dynamic ultrasound can demonstrate median nerve level changes in response to wrist movements. Furthermore, a typical gliding pattern was characterized. The presence of level change and gliding patterns were proposed as additional movement parameters during wrist flexion in healthy individuals.
Aim of the study: Intraneural ganglion cysts are a relatively uncommon type of ganglion cyst that can affect peripheral nerves. They are particularly rare in the upper limb, and even more so in the median nerve, with the vast majority of them occurring in the peroneal nerves. This paper aims to make the reader aware of this relatively uncommon condition.
Case description: We report a case of a 41-year-old male who presented with a gradually progressing mass on the volar aspect of the wrist extending to the index finger. The nonspecific presentation as well as the rarity of the condition may make diagnosis challenging. The patient was referred for surgical management under a specialist peripheral nerve hand surgeon.
Conclusions: Ultrasound and magnetic resonance imaging as well as awareness of the typical imaging features of this entity are crucial in making the correct diagnosis as well as excluding other potential considerations such as neoplasm.
Aim of the study: To describe the sonographic appearance of pronator teres syndrome and the role of ultrasound-guided hydrodissection for its management.
Case description: Pronator teres syndrome is a well-known compressive neuropathy of the median nerve between the two heads of pronator teres. However, the clinical presentation of this syndrome can be indolent with vague pain at the proximal volar forearm leading to a delay in diagnosis. We describe our experience in the management of pronator teres syndrome in a healthy young badminton player with ultrasound-guided median nerve hydrodissection. We highlight the clinical presentation, the role of dynamic Ultrasound scan (USS) in the diagnosis and effective treatment of pronator teres syndrome.
Conclusions: In conclusion, managing PTS can be challenging, and this case highlights the importance of ultrasound-guided hydrodissection, when conservative measures have failed to improve the symptoms. Further studies are required to assess and compare the long-term outcomes of these interventions.