Controlled clinical trials and efficacy: report of a neurosurgical study

Dear Editor:

I was particularly interested by a recent article published in your journal, on the “efficacy” and safety of microsurgical treatment of trigeminal neuralgia.¹ Without discrediting the valuable results reported, the article opens a debate on the importance of proper reporting of research by the type of results obtained. Talking about efficacy in a retrospective, observational study using data from medical histories and comparing different age groups is certainly the result of poor comprehension and interpretation of methodological rigour, a pillar of clinical research, which enables us to distinguish between different types of research according to their validity. It is widely known that the efficacy of an intervention is assessed with clinical studies conducted in “controlled conditions,” whereas the effectiveness of an intervention is shown in observational studies in “real conditions,”^2–4 as in the mentioned study.

In the field of neurosurgery, there has been a considerable decrease in the use of rigorous analytical designs to assess the efficacy of an intervention, as used in controlled clinical trials; the trend over the past 20 years shows that there has not been a proportional increase in the disciplines of neurology and neurosurgery, as is clear from the statistical figures obtained from studies included on the MEDLINE database (Fig. 1) (Source: data obtained from MEDLINE, available from: https://www.ncbi.nlm.nih.gov/pubmed/).

Figure 1.

Clinical trials in neurology and neurosurgery published on MEDLINE over the past 20 years.

One of the causes related to this poor progression may be the inherent difficulty of performing adequately controlled and randomised trials with this type of patients⁴; however, this justification should not diminish the quality of the limited number of efficacy studies in neurosurgery; rather, it should help us improve the quality of the reports from observational studies. In this respect, we should mention the promotion work carried out by the EQUATOR network, an international initiative to improve the reliability and value of healthcare research literature.⁵ The proposed guidelines include the STROBE initiative,⁶ aimed at reporting observational studies; this is an appropriate tool for the published study, which should be reviewed by the authors.