T 2052/09 – Cutting The Bone

This is an examination appeal that might help you become familiar with some intricacies of G 1/07.

The application dealt with guidance in adjusting bone incision blocks. Its independent claims were directed at a bone incision block with an incision guide comprising an adjustable localisation reference that allows to define an incision plane (claim 1) and a method claim 12 that read (English translation):

Method for user guidance in setting an incision plane of an incision guide (2) of a bone incision block (1) that comprises an incision guide adjustment device (4), wherein

• a target incision plane is defined ;
• an actual incision plane is spatially determined by means of a localisation reference (6) that is adjustably, e.g. rotatably, attached to the incision guide (2) ;
• the spatial position of the adjustment device (4) is determined by means of a registration element (5); and wherein
• depending on the spatial position of the adjustment device (4), adjustment instructions are output, which, starting from the actual incision plane, assist the user in setting the target incision plane.

The Examining Division (ED) was of the opinion that the two first steps of the claimed method necessarily implied fastening the bone incision block to the bone, so that the method comprised a surgical step and was excluded from patentability under A 53(c).

The applicant filed an appeal. Its new main request contained a method claim 10 that read:

Method for user guidance in setting an incision plane of an incision guide (2) of a bone incision block (1) that comprises an incision guide adjustment device (4) and that has been fastened to a bone before the method is carried out, wherein

• a target incision plane is defined ;
• an actual incision plane is spatially determined by means of a localisation reference (6) that is adjustably, e.g. rotatably, attached to the incision guide (2) ;
• the spatial position of the adjustment device (4) is determined by means of a registration element (5) comprising a reference that is fastened (fest angeordnet) to the adjustment device (4), wherein the reference is punctiform or two-dimensional; and wherein
• depending on the spatial position of the adjustment device (4), adjustment instructions are output, which, starting from the actual incision plane, assist the user in setting the target incision plane. (my emphasis)

In what follows the Board deals with the question of whether this method is surgical within the meaning of the EPC.

*** Translation of the German original ***

Surgical methods

The method claim on which the decision of the ED was based

[2.1] The ED was of the opinion that the two first steps of the claimed method, i.e. the definition of a target incision plane and the spatial determination of an actual incision plane by means of a localisation reference that is adjustably, e.g. rotatably, attached to the incision guide, necessarily imply fastening the bone incision block to the bone, so that the method comprised a surgical step and, therefore, was excluded from patentability under A 53(c).

The actual incision plane can indeed only been determined when the incision guide of the bone incision block is in a fixed relation to the bone, i.e. when the bone incision block has been anchored to the bone.

Even if it is possible in theory to maintain the bone incision block in its position without anchoring it to the bone, as the appellant has asserted, in the opinion of the Board this does not change the fact that the general wording of the claim also encompasses the situation where it is fastened to the bone, i.e. a surgical step, as described, for instance in paragraphs [0019] and [0029] of the description:”

“The bone incision block 1 is fastened to a lower leg bone 20 via its fastener 3 (Figure 2), and in particular screwed on or held by Schanz screws, Kirschner wires or similar fastening media. The adjustment device 4 is connected to the fastener 3 and the incision guide 2 is fixed to the adjustment device 4. ”

“When the incision guide 2 and the adjustment device 4 are connected to one another in a desired configuration, the localisation reference 6 is attached to the incision guide 2. When assembled, the bone incision block 1 can be placed (e.g., screwed) onto the bone at any point near the resection area. ”

In its decision G 1/07 [headnote 2a], which has been issued in the meantime, the Enlarged Board has confirmed that “a claim which comprises a step encompassing an embodiment which is a “method for treatment of the human or animal body by surgery” within the meaning of A 53(c) cannot be left to encompass that embodiment.”

Thus the Board shares the opinion of the ED in regard of the method claim on which it had to decide.

The appellant was of the opinion that exceptional provisions had to be interpreted narrowly and that, as a consequence, the claimed method was not to be excluded from patentability.

However, according to G 1/07 [3.1], no general principle of narrow interpretation of exclusions from patentability which would be applicable a priori to the interpretation of any such exclusions can be derived from the Vienna Convention on the Law of Treaties. Rather, an exceptional provision of the EPC has to be interpreted in the same manner as any other provision on patentability, i.e. in such a manner that it takes its effect fully and achieves the purpose for which it was designed.

Main request

Method claim 10

[2.2.1] In contrast to the method claim on which the impugned patent was based, the wording of present claim 10 now is:

Method for user guidance in setting an incision plane of an incision guide (2) of a bone incision block (1) that comprises an incision guide adjustment device (4) and that has been fastened to a bone before the method is carried out, …

The addition of “fastened to a bone before the method is carried out” is intended to express that the step of fastening the bone incision block to the bone is not claimed or takes place before the claimed method begins, respectively.

The remaining wording of the method claim was not amended, and the first method step still reads: “a target incision plane is defined”.

As a consequence, the present wording of the method claim is directed at a method where the target incision plane is only to be defined after the bone incision block has been fastened to the bone.

[2.2.2] Thus the question arises whether the method that is being claimed is not covered by A 53(c) any more, and/or whether it is admissible at all in the case of the disclosed method to exclude the surgical step of fastening the bone incision block to the bone in this way, respectively.

First it has to be noted that contrary to the opinion of the appellant, the wording it has chosen (“fastened to a bone before the method is carried out”) does not qualify as a “disclaimer solution” according to G 1/07 [4.2.1]. What is to be examined here is the omission or exclusion of a step, which is discussed in G 1/07 [4.3].

[2.2.3] The Board is of the opinion that the method disclosed in the original application does not envisage the case where the target incision plane is defined in the operating theatre, i.e. during surgery, after the bone incision block has been fastened to the bone.

Quite to the contrary, in the computer-assisted bone resection method disclosed in the present application the target incision plane is not defined in the operating theatre but before, during the diagnosis or therapy planning phase, respectively. The target incision plane is then stored in the navigation system, as can be seen, for instance, from paragraph [0004] (underlining added):

“An adjustment means can be used to set the incision plane in the ‘slope’, ‘varus-valgus’ and ‘resection depth’ degrees of freedom typical for bones, in accordance with the pre-sets of the navigation system (target incision plane). However, this can be problematic when the bone incision block (in particular the adjustment means) is fastened to the bone such that the operating elements are not clearly assigned to the degrees of freedom of the incision plane defined by the incision guide. In such cases, for example, operating an element may result in a change in more than one degree of freedom, or two operating elements may need to be activated in order to adjust in one degree of freedom.

Finding the most favourable way to complete the adjusting process in the shortest period of time then depends largely on the knowledge and experience of the operator. Although the target incision plane is pre-set by navigation, it is often difficult to set the incision guide in accordance with target incision plane and/or pre-sets without assistance, especially if the incision block is arranged unfavourably on the bone. If unfavourably arranged on the bone, an iterative procedure may be necessary, since direct adjusting using the interdependence of the functional members is not possible.”

The other parts of the application do not disclose a specific method where the target incision plane is determined after the bone incision block has been fastened to the bone, either.

Quite to the contrary, according to the original application, in computer-assisted bone resections the actual incision plane has to be aligned (zur Deckung gebracht) with the target incision plane as quickly and precisely as possible (see e.g. paragraph [0005]). The obvious purpose of this is to keep the operating time as short as possible. Thus defining the target incision plane during the surgery, i.e. after fastening the bone incision block to the bone, would also run counter to the problem to be solved because the precise baselines (? Gründe) and the precise position of the position of the target incision plane would have to be determined during the surgery. It would be unusual to proceed in this way in the case of computer-assisted bone resections because it is much simpler and reasonable to define the target incision plane in advance, based on bone imagery. Thus the original disclosure does not contain, even implicitly, a method where the target incision plane is determined after the bone incision block has been fastened to the bone   

Moreover, the appellant has not provided the Board of appeal with any argument in this respect.

[2.2.4] In the present case the solution proposed by the appellant in order to avoid the A 53(c) objection, i.e. the exclusion of the surgical step, is not available.

As already mentioned above, the original application only discloses a method where the target incision plane is determined before the bone incision block is fastened to the bone. Thus the method disclosed in the original [application] necessarily comprises the surgical step of fastening the bone incision block to the bone (see e.g. T 1005/98).

Therefore, it is not possible to exclude a surgical step that necessarily occurs, from a method claim if this step, in view of the overall disclosure of the application, necessarily occurs during and not before or after the disclosed method.

By fastening the bone incision block to the bone the actual incision plane is determined. It is a purpose of the invention to align the actual incision plane with a predetermined target incision plane as quickly and precisely as possible. Thus it is of central importance to the problem to be solved by the invention to attach the bone incision block to the bone after the target incision plane has been determined.

Consequently, this is not a surgical method step - to be performed on the body - which, although necessary for carrying out the claimed method, has no functional link with it and which could be excluded from the claim in the way requested by the appellant, in application of G 1/07 [4.3.2] (as, for instance, when a reference element is attached to the bone so that a method for determining the position of a bone guidance wire can then be carried out (see e.g. T 836/08 [3]) or, under certain circumstances, when a contrast agent is injected before  an imaging method is performed, see T 266/07 [4]). Moreover, the present case does not concern a mere operating procedure for a device. Rather, fastening the bone incision block to the bone after the target incision plane has been determined is an essential step without which the sequence of the claimed method steps cannot be carried out at all and which cannot be excluded under A 84 in connection with R 43 because the invention is not fully and completely defined without this step (see G 1/07 [4.3.1]).

Thus it is not possible in the present case to exclude the step of fastening the bone incision block to the bone in order to overcome the A 53(c) objection.

[2.5] Therefore, the main request cannot be allowed.

NB: The English translation of a similar case (T 923/08) is available on this blog (here).

Should you wish to download the whole decision (in German), just click here.

The file wrapper can be found here.