The intersection syndrome: Ultrasound findings and their diagnostic value

Abstract

Introduction

The intersection syndrome is a well-known overuse syndrome of the distal forearm. It is characterized by noninfectious, inflammatory changes involving the area of intersection of the first (abductor pollicis longus and extensor pollicis brevis) and second (extensor carpi radialis longus and extensor carpi radialis brevis) extensor compartments in the dorsoradial aspect of the distal forearm. Imaging modalities used to diagnosis this syndrome include ultrasonography (US) and magnetic resonance imaging. The purpose of this report is to describe typical US findings in the intersection syndrome and to demonstrate the diagnostic value of this approach.

Materials and methods

We reviewed US findings in 4 patients (mean age 40 years) referred to our staff for symptoms suggestive of the intersection syndrome (pain, swelling, erythema, and edema of the wrist).

Results

In all 4 cases, the US examination revealed peritendinous edema and synovial fluid within the tendon sheaths at the intersection between the first and the second dorsal extensor tendon compartments.

Discussion

Our experience shows that the intersection syndrome is associated with typical signs on US. This imaging modality can be considered a reliable tool for diagnosing this syndrome and may eliminate the need for other more expensive tests.

Sommario

Introduzione

La sindrome intersezionale è una sindrome infiammatoria che coinvolge i tendini del primo (abduttore lungo del pollice ed estensore breve del pollice) e secondo (estensore radiale lungo e breve del carpo) compartimento dei muscoli estensori della mano. Le tecniche di imaging utili per lo studio di questa patologia sono rappresentate dall’ecografia e dalla Risonanza Magnetica. Il nostro studio ha avuto come obiettivo la descrizione del quadro ecografico di tale affezione allo scopo di dimostrare l’importanza e l’esaustività della metodica.

Materiali e metodi

Sono stati inclusi nello studio quattro pazienti, di età compresa tra 28 e 53 anni, con sintomatologia clinica riconducibile alla sindrome intersezionale (dolore, gonfiore, eritema o edema nella regione del polso).

Risultati

Il quadro ecografico della sindrome intersezionale in tutti i casi ha mostrato la presenza di edema peritendineo e versamento sinoviale all’interno delle guaine tendinee dei tendini del primo e secondo compartimento determinando la scomparsa del piano divisorio iperecogeno tra i due gruppi tendinei.

Discussione

I risultati della nostra esperienza confermano che la metodica ecografica fornisce segni tipici in tale affezione e pertanto può essere considerata come tecnica sufficente per lo studio di pazienti con sintomatologia riconducibile alla sindrome intersezionale.

Introduction

Ultrasonography plays a fundamental role as a first-line imaging study in the diagnosis of musculotendinous injuries. The intersection syndrome is a noninfectious, inflammatory condition that affects that portion of the distal forearm where the first extensor compartment tendons (those of the abductor pollicis longus and the extensor pollicis brevis) pass over—or intersect—those of the second extensor compartment (the extensor carpi radialis longus and the extensor carpi radialis brevis tendons). In patients suffering from this syndrome, US reveals tenosynovitis (synovial fluid within the tendon sheaths) and peritendinous edema. The underlying pathophysiological mechanisms are still the subject of debate, but the syndrome is clearly caused by overuse of the muscles of the forearm, which is associated with typical signs and symptoms [1], including pain, swelling, erythema, edema at palpation, and crepitus during flexion and extension of the wrist. The area of involvement is proximal to the Lister tubercle of the distal radius [2], and pain is reported at the point of intersection between the extensor tendons of the first and second compartments [3].

The intersection syndrome must be differentiated from inflammatory forms of tenosynovitis (particularly De Quervain’s disease), ganglion cysts, infections, sprains involving the ligaments of the wrist, muscle strains, soft-tissue tumors, and Wartenberg’s syndrome (entrapment of the sensory branch of the radial nerve) [4].

The aim of our study was to demonstrate the value of US in the work-up of patients with the intersection syndrome based on a review of cases diagnosed by our group.