The distal intersection syndrome relates to tenosynovitis of the extensor pollicis longus (EPL) tendon (3rd extensor compartment), where it crosses the extensor carpi radialis longus (ECRL) and brevis (ECRB) tendons (2nd extensor compartment) 1. It is distinct from intersection syndrome which occurs more proximally in the forearm at the intersection of the first and second extensor compartments.
The crossing of the second extensor compartment is typically located just distal to Lister’s tubercle. The tendon sheaths of the EPL and the ECRB are connected by a communicating foramen 2. This is probably why inflammation of the EPL tendon spreads to the second compartment or vice versa.
Pain and swelling over Lister’s tubercle. Less commonly, local crepitus during thumb movements.
Various mechanisms, including:
- attrition is related to a biomechanical pulley effect by Lister’s tubercle (overuse syndrome)
- direct blunt trauma of the EPL tendon
- distal (not necessarily displaced) radius fracture
Trauma is the most frequent cause. EPL tenosynovitis usually occurs within 8 weeks, but can still be found years after an injury.
May show peritendinous edema and fluid within the tendon sheaths at the intersection point between the 2nd and 3rd dorsal extensor tendon compartments 6.
Typically shows features of peritendinous edema (peritendinitis) around the 2nd and 3rd extensor compartment tendons, extending proximally from the crossover point of the EPL in the dorsal wrist.
Treatment and prognosis
An early operative release is advocated due to a high risk of EPL tendon rupture (drummer boy’s palsy) 3.
On imaging consider:
- 1. Parellada AJ, Gopez AG, Morrison WB et-al. Distal intersection tenosynovitis of the wrist: a lesser-known extensor tendinopathy with characteristic MR imaging features. Skeletal Radiol. 2007;36 (3): 203-8. doi:10.1007/s00256-006-0238-6 - Pubmed citation
- 2. Cvitanic OA, Henzie GM, Adham M. Communicating foramen between the tendon sheaths of the extensor carpi radialis brevis and extensor pollicis longus muscles: imaging of cadavers and patients. AJR Am J Roentgenol. 2007;189 (5): 1190-7. doi:10.2214/AJR.07.2281 - Pubmed citation
- 3. Denman EE. Rupture of the extensor pollicis longus--a crush injury. Hand. 1979;11 (3): 295-8. - Pubmed citation
- 4. Costa CR, Morrison WB, Carrino JA. MRI features of intersection syndrome of the forearm. AJR. American journal of roentgenology. 181 (5): 1245-9. doi:10.2214/ajr.181.5.1811245 - Pubmed
- 5. Zhari B, Edderai M, Boumdine H, Amil T, En-nouali H. Dual intersection syndrome of the forearm: a case report. The Pan African medical journal. 21: 325. doi:10.11604/pamj.2015.21.325.4105 - Pubmed
- 6. Montechiarello S, Miozzi F, D'Ambrosio I, Giovagnorio F. The intersection syndrome: Ultrasound findings and their diagnostic value. Journal of ultrasound. 13 (2): 70-3. doi:10.1016/j.jus.2010.07.009 - Pubmed
- 7. Lee RP, Hatem SF, Recht MP. Extended MRI findings of intersection syndrome. Skeletal radiology. 38 (2): 157-63. doi:10.1007/s00256-008-0587-4 - Pubmed
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