Dear Editors,

I recently read an article published in your journal, by van Munster et al., which presented an informative insight into the historical aspects of regional variation in tonsillectomy.^{Reference van Munster, Zamanipoor Najafabadi, Schoones, Peul, van den Hout and van Benthem1} Tonsillectomy is a widespread procedure surrounded by a decades-long controversy regarding variation in practice. I agree with their conclusions that international efforts are needed to establish greater clarity on the causes of this regional variance; however, I wish to draw from the UK experience to demonstrate some explanatory factors, and to suggest further causes for the increase in tonsillectomy incidence at the start of the twentieth century.

Glover's 1938 article was the first of several attempts to account for geographical variation in tonsillectomy rates,^{Reference Glover2} and this led to numerous initiatives from the UK's Medical Research Council to analyse and explain this phenomenon. The Medical Research Council facilitated a survey of school medical officers in the late 1950s, which demonstrated not only extensive geographical variance in school-age children who had undergone tonsillectomy (between 0.5 and 25 per cent), but also significant variance with socioeconomic status (incidence ranged from 14.3 per cent in technical schools to 37.9 per cent in grammar schools).^{Reference Henderson3} Later in the century, the Medical Research Council commissioned an investigation by medical sociologist MJ Bloor. Bloor's study identified greater variation between medical practitioners in a single geographical location, compared with between locations,^{Reference Bloor4} which he explained through specific differences in assessment and decision-making strategies between clinicians.^{Reference Bloor5} This reinforced Glover's original conclusions that differences in rates were accounted for by differences in medical opinion.

At the start of the twentieth century, tonsillectomy rates rose rapidly. As van Munster et al. report, this was partly due to the dominant epistemology at the time – the focal theory of infection, which attributed systemic illness to local disease. However, several other factors influenced this new popularity. In the UK, an increase in the medical surveillance of children (e.g. through the School Medical Service) occurred just as medical services were becoming more accessible with social programmes such as the National Health Insurance Act (1911).^{Reference Webster6} This facilitated greater identification of tonsil disease in children, while also making interventions available financially to a broader section of the population. Furthermore, it was during this period that otorhinolaryngology was formalised as a specialty, and this surgical procedure on the tonsils – where the ears, nose and throat meet – would anatomically represent this evolving discipline.^{Reference Yalamanchili7} As I have argued elsewhere, the focal theory played an important role in the popularity of tonsillectomy; however, there were also important structural, financial and political incentives for the growth of the procedure.^{Reference Dwyer-Hemmings8}

Attention to the UK's historical experience allows us to gain an understanding of the factors implicated in the geographical variance of tonsillectomy rates, and helps explain why variance persists despite stricter indications and guidelines. The role of socioeconomic status and practitioner decision-making must be accounted for in future research in this area, and attention to these factors will facilitate evidence-based reflective practice and ensure that interventions are appropriate and justified.