In G 1/07 the Enlarged Board of Appeal disapproved of the broad construction of interventions of a surgical nature corresponding to the practice of the EPO, such as in decisions T 182/90 and T 35/99, namely that all methods involving irreversible damage to or destruction of living cells or tissues of the living body were regarded as non-insignificant interventions and thus as surgical treatments, irrespective of the underlying mechanism of the intervention (e.g. mechanical, electrical, thermal, chemical). According to the Enlarged Board this view was overly broad when considering today's technical reality. The definition given obiter dicta in G 1/04 that ""any physical intervention" on the human or animal body…" is a method of surgery within the meaning of Art. 52(4) EPC 1973 appeared too broad.
A narrower understanding of "treatment by surgery" was required. Any definition of the term "treatment by surgery" must cover the kind of interventions which represent the core of the medical profession's activities, i.e. the kind of interventions for which their members are specifically trained and for which they assume particular responsibility. Such a narrower understanding rules out uncritical methods involving only a minor invention and no substantial health risks.
The Enlarged Board found itself unable to give a definition which would delimit the exact boundaries of a new concept of treatment by surgery. The field of methods which potentially involves surgical steps is vast, so that each category of class will have to be assessed on its own merits.
In G 1/07, the Enlarged Board indicated the direction it expected future practice and case law to take, finding that the exclusion from patentability should not be applied to methods in respect of which the interests of public health, of protection of patients and as a counterpart to that of the freedom of the medical profession to apply the treatment of choice to their patients does not call for their exclusion from patentability. It is for the departments of first instance and the boards to define the boundaries of a more narrowly construed concept of "treatment by surgery", based on the technical reality of the individual case under consideration.
The required medical expertise and the health risk involved may not be the only criteria which may be used to determine that a claimed method actually is a "treatment by surgery" within the meaning of Art. 53(c) EPC. It appears that what is to be understood by "surgery" in the medical sense is to a large extent a matter of convention. Thus, in order to be surgical, it is not necessary that the intervention be invasive or that tissues be penetrated (T 5/04). The scope of what is surgery may change with time and with new technical developments emerging, as was already acknowledged in decision T 182/90.
With regard to the facts of the case the Enlarged Board decided in G 1/07 that a claimed imaging method, in which, when carried out, maintaining the life and health of the subject is important and which comprises or encompasses an invasive step representing a substantial physical intervention on the body which requires professional medical expertise to be carried out and which entails a substantial health risk even when carried out with the required professional care and expertise, is excluded from patentability as a method for treatment of the human or animal body by surgery pursuant to Art. 53(c) EPC.