Synthesis of the relative confluence level as an assessment metric for the urogenital sinus in female children with congenital adrenal hyperplasia: surgical implications of the developmental hypotheses

Abstract Background Congenital adrenal hyperplasia in females leads to virilisation of the external genitalia and an internally anomalous genitourinary tract, in the form of apparent persistence of the urogenital sinus and a common termination of the urethra and the vagina. Surgical repair is indicated to raise a female child with external genitalia matching her gender and to avoid psychosocial discordance and, in some cases, genitourinary complications. The debate around earlier versus later surgery is affected, and could be enriched by insights into the variations in the anatomical assessment of the severity of anomaly preoperatively. Abstract main body In this conundrum, there was a need for a reliable preoperative severity stratification. This work is an in-depth review and analysis of efforts into this specific aspect, across a series of key publications in this field, of others and ours. We propose a link between the two previously known hypotheses about this anomaly, one being a dynamic androgen-dependent development and the other being a static androgen-independent development, by stipulating that although the vaginal depth (and hence operative complexity) occur in a spectrum rather than either high or low, this spectrum is concentrated in its middle one-third, where the vagina joins the urethra near the point of the pseudo-verumontanum, or exactly at it (in the extreme end of the spectrum). The degree of external virilisation does not fully or strongly correlate with the internal anatomy, and hence the pertinent internal aspects of the operative complexity. Age and size variations between patients lead to difficulties with comparability and interobserver variability/reliability. Conclusion This led to the development of two key metrics: (a) the confluence depth (absolute) measurement and hence (b) a size and age-independent calculated confluence ratio , which directly affect the operative complexity. Insights and views of key research groups recently addressing and contributing to this topic were contrasted, summarised and aligned.