Ultrasonographic findings in cubital tunnel syndrome caused by a cubitus varus deformity

Hearing and Seeing Nerve/Tendon Snapping: A Systematic Review on Dynamic Ultrasound Examination

Nerve/tendon snapping can occur due to their sudden displacement during the movement of an adjacent joint, and the clinical condition can really be painful. It can actually be challenging to determine the specific anatomic structure causing the snapping in various body regions. In this sense, ultrasound examination, with all its advantages (especially providing dynamic imaging), appears to be quite promising. To date, there are no comprehensive reviews reporting on the use of dynamic ultrasound examination in the diagnosis of nerve/tendon snapping. Accordingly, this article aims to provide a substantial discussion as to how US examination would contribute to 'seeing' and 'hearing' these pathologies' different maneuvers/movements.

A cadaveric study of ulnar nerve strain at the elbow associated with cubitus valgus/varus deformity

Background

Cubital tunnel syndrome can be caused by overtraction and dynamic compression in elbow deformities. The extent to which elbow deformities contribute to ulnar nerve strain is unknown. Here, we investigated ulnar nerve strain caused by cubitus valgus/varus deformity using fresh-frozen cadavers.

Methods

We used six fresh-frozen cadaver upper extremities. A strain gauge was placed on the ulnar nerve 2 cm proximal to the medial epicondyle of the humerus. For the elbow deformity model, osteotomy was performed at the distal humerus, and plate fixation was performed to create cubitus valgus/varus deformities (10°, 20°, and 30°). Ulnar nerve strain caused by elbow flexion (0–125°) was measured in both the normal and deformity models. The strains at different elbow flexion angles within each model were compared, and the strains at elbow extension and at maximum elbow flexion were compared between the normal model and each elbow deformity model. However, in the cubitus varus model, the ulnar nerve deflected more than the measurable range of the strain gauge; elbow flexion of 60° or more were considered effective values. Statistical analysis of the strain values was performed with Friedman test, followed by the Williams’ test (the Shirley‒Williams’ test for non-parametric analysis).

Results

In all models, ulnar nerve strain increased significantly from elbow extension to maximal flexion (control: 13.2%; cubitus valgus 10°: 13.6%; cubitus valgus 20°: 13.5%; cubitus valgus 30°: 12.2%; cubitus varus 10°: 8.3%; cubitus varus 20°: 8.2%; cubitus varus 30°: 6.3%, P < 0.001). The control and cubitus valgus models had similar values, but the cubitus varus models revealed that this deformity caused ulnar nerve relaxation.

Conclusions

Ulnar nerve strain significantly increased during elbow flexion. No significant increase in strain 2 cm proximal to the medial epicondyle was observed in the cubitus valgus model. Major changes may have been observed in the measurement behind the medial epicondyle. In the cubitus varus model, the ulnar nerve was relaxed during elbow extension, but this effect was reduced by elbow flexion.

Peripheral nerve injuries in the pediatric population: a review of the literature. Part II: entrapment neuropathies

INTRODUCTION

Entrapment neuropathies are infrequent in children, and therefore remain unrecognized. The incidence of radial, median, and cubital mononeuropathies are all similar. Despite the rarity of such cases, extensive, albeit scattered, literature has accumulated concerning entrapment neuropathies in children.

OBJECTIVE

To the literature concerning entrapment neuropathies in children.

METHODS

A systematic review of the existing literature has been made.

RESULTS

The management of chronic pediatric pain is very important in such patients to prevent youths from experiencing prolonged absences from school, sports, or other productive activities, and limit the psychological burden of chronic disease. Nonsurgical treatment of both cubital and carpal tunnel syndromes has been disappointing in pediatric patients, with only limited success; and, to date, there is no clear explanation for the outcome differences generated by nonsurgical management between adults and youths. Simple decompression of the ulnar nerve at the elbow also has much higher rates of failure in children than in adults.

CONCLUSIONS

The presence of an entrapment neuropathy (specially carpal tunnel syndrome) in a pediatric-age patient should alert medical care providers to the potential of some underlying genetic condition or syndrome.