Analysis of the Anatomical Factors Associated with Cubital Tunnel Syndrome.

BACKGROUND

Previous studies demonstrated that soft tissues, such as retinaculum, fibrous band, and anconeus, cause ulnar nerve compression, whereas other studies showed that the bony structures strain the ulnar nerve that runs directly behind the medial epicondyle constituting the boundary of the cubital tunnel during elbow flexion. However, no studies have reported the association of the shape of the bony structure with cubital tunnel syndrome symptoms. Are computed tomography (CT) and magnetic resonance imaging (MRI)-measured parameters of the bony cubital tunnel related to idiopathic cubital tunnel syndrome symptoms?

HYPOTHESIS

We hypothesized that CT and MRI-measured parameters of the bony cubital tunnel were related to idiopathic cubital tunnel syndrome symptoms. We aimed to investigate the relationship between the radiographic parameters based on CT and MRI and idiopathic cubital tunnel syndrome symptoms.

PATIENTS AND METHODS

We analyzed 224 elbows (77 affected elbows of patients with idiopathic cubital tunnel syndrome, 77 unaffected elbows of patients with cubital tunnel syndrome, 70 elbows of patients without cubital tunnel syndrome symptoms) using CT and MRI. Cubital tunnel cross-sectional area, cubital tunnel volume, and ulnar nerve cross-sectional area were measured in the three groups at flexion and extension. A new cubital tunnel center with a new boundary was proposed that could play a role in ulnar nerve compression symptoms.

RESULTS

The cross-sectional areas and volumes of the cubital tunnel measured in the elbow flexion state were the smallest among the group with the affected elbows in patients. There was no difference between unaffected elbows and the non-patient group. The cross-sectional area of the ulnar nerve highly correlated with cubital tunnel symptoms in the flexion state.

DISCUSSION

The shape of the cubital tunnel is an important factor in cubital tunnel syndrome, and normal variations in the volume and cross-sectional area of the cubital tunnel and ulnar nerve could influence the occurrence of idiopathic cubital tunnel syndrome.

LEVEL OF EVIDENCE

III, Therapeutic study.