classification
Last reviewed 01/2018
A variety of classification schemes have been proposed for congenital upper limb anomalies. These include embryological, teratologic and anatomical schemes. With advances in genomic screening, it is likely molecular schema will be available in the future. However, there utility may be limited given that there is great redundancy of the pathways involved in limb formation and hence multiple genes mutations may be implicated in many cases, and also, there is currently no genetic in utero treatment to ameliorate any mutation. Consequently, teratologic or anatomic schemes remain the most widely used as they give practical guidance as to management.
The Swanson(1) Classification system is a standard system that is used to categorise congenital limb anomalies. It was based upon the work of Frantz and O'Rahilly(2). It has been adopted by the American Society of Surgery of the Hand and the International Federation of Societies of Surgery of the Hand.
The system is based upon the prediction of an embryonic failure during development leading to clinical features that are used for identification. When features of more than one anomaly are present, the most predominant determines which of seven categories the patient should be identified as having:
- failure of formation
- failure of differentiation
- duplication
- overgrowth
- undergrowth
- constriction ring syndromes
- generalised conditions
Ref: (1) Frantz CH, O'Rahilly R (1961). J Bone Joint Surg 43: 1202-1224. (2) Swanson AB (1976). J Hand Surg 1: 8-22.