Ischiopubic synchondrosis asymmetry is the characteristic enlargement of one of the ischiopubic synchondroses. While it most commonly a normal variant of the developmental process, it is sometimes thought to be syndromic (then called ischiopubic synchondrosis syndrome or van Neck-Odelberg disease) in symptomatic children with groin pain. It is most frequently an incidental finding on imaging.
Occurs in all children before puberty during fusion of the pubic and ischial bones 3.
Ischiopubic synchondrosis asymmetry is much more common on the side of the weight-bearing non-dominant foot, with the differences in ossification thought to result from asymmetric mechanical forces 3.
Recognition of entity as a normal variant is important for radiologists when interpreting a paediatric pelvic radiograph. One of the key questions to ascertain is whether the region is painful or not:
- if asymptomatic and there is no concerning antecedent history: it is unlikely to represent a sinister pathology other than just a developmental variant
- if symptomatic or if the there is concerning antecedent history: it could still be a developmental variant although other important differential considerations should also be considered
On imaging alone the condition can mimic many other pathological entities including:
The preceding clinical history is crucial in image interpretation.
History and etymology
The condition is named after M van Neck and A Odelberg who initially described these findings in 1924 4,5.
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- 4. van Neck M. Osteochondrite du pubis. Arch Franco-Belg Chir 1924;27:238 –241
- 5. Odelberg A. Some cases of destruction in the ischium of doubtful etiology. Acta Chir Scand1924 ;56:273
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- 9. Kloiber R, Udjus K, McIntyre W et-al. The scintigraphic and radiographic appearance of the ischiopubic synchondroses in normal children and in osteomyelitis. Pediatr Radiol. 1988;18 (1): 57-61. Pubmed citation