T 1033/08 20-07-2011

Reasons for the Decision

1. The appeal is admissible.

2. Late-filed submissions

2.1 Late-filed documents

Documents E7 and E8 are regarded by the Board as more relevant than E1 in that they disclose ablating systems with multiple emitters (electrodes) each having multiple sensors, whereas E1 only teaches either a single ablating electrode 14, 27 with multiple sensors 24 (Figures 1 to 3) or a plurality of conductive ablating segments 40 each having a single sensor 42 (Figures 5 and 6). The filing of E7 and E8, directly with the statement of grounds of appeal, is considered a justified reaction to the impugned decision. The Board therefore admits these documents into the appeal proceedings.

2.2 Late-filed auxiliary requests

The second auxiliary request corresponds to the version as upheld by the Opposition Division and is thus not late-filed. The first and third auxiliary requests comprise amendments introduced in order to overcome a minor clarity objection addressed in the Board's communication. Therefore all these auxiliary requests are admitted by the Board into the appeal proceedings in exercise of its discretion under Article 13(1) and (3) RPBA as far as their late-filing is concerned.

3. Main and first auxiliary requests - allowability

Claim 1 as upheld by the Opposition Division (current second auxiliary request) is restricted to the selection of the hottest one of the measured temperatures for each energy emitter of the ablation system for comparison to a desired temperature (cf. feature (D4) in the denotation given below in point 5.2.1). By contrast, claim 1 of the main and the first auxiliary requests is of broader scope since the selection of the hottest one of the measured temperatures is carried out for at least one of the energy emitters. Consequently, the subject-matter of claim 1 of the main and first auxiliary requests, by covering the possibility of selecting the hottest one of the measured temperatures for any selection of the energy emitters, is broader than that of claim 1 upheld by the Opposition Division. This results in an improvement of the proprietor's position putting the sole appellant in a worse situation than if he had not appealed, contrary to the principle of prohibition of reformatio in peius.

The opponent is the sole appellant against the interlocutory decision of the Opposition Division concerning maintenance of the patent in amended form according to the respondent's main request filed in opposition proceedings. The proprietor is not adversely affected and has implicitly indicated that he will not contest the maintenance of the patent in the version accepted by the Opposition Division (G 1/99, point 9.1 of the Reasons). As ruled in G 9/92 and G 4/93 (see Headnote II and Reasons, points 15 and 16), under these circumstances the patent proprietor is primarily restricted during the appeal proceedings to defending his patent in the form in which it was maintained by the Opposition Division. In particular, the patent proprietor is not permitted to improve his position to the detriment of the opponent and sole appellant. Amendments proposed by the patent proprietor as a party as of right under Article 107 EPC, second sentence, may be rejected as inadmissible by a board of appeal if they are neither appropriate nor necessary.

Contrary to the respondent's view, G 1/99 does not supersede G 9/92 and G 4/93, but is complementary thereto in that it gives directions for allowing an exception to the principle of prohibition of reformatio in peius as defined in these decisions. However, the exception to this principle developed in G 1/99 does not apply in the circumstances of the present case for the following reasons.

G 1/99 only deals with the deletion of a limiting feature added during the opposition procedure. The exception to the principle of prohibition of reformatio in peius applies to this situation only (see point 2.3 of the Reasons).

In fact, in order to allow such a deletion which puts the opponent and sole appellant in a worse situation than if he had not appealed, the following conditions must be fulfilled:

A limiting feature introduced during the opposition procedure has to be deleted. The necessity for its deletion must be caused by the appeal. This means that the deletion is necessary and appropriate because it is related to a ground of opposition and caused by new facts, evidence or arguments put forward by the appellant, or because of a different evaluation of the situation by the board of appeal. Without the deletion, the patent would have to be revoked. It is not possible to overcome the objection by introducing new features which limit the scope of the patent as maintained.

Only if these preconditions are fulfilled, an objection may be overcome by introducing new features which extend the scope of the patent as maintained, but within the limits of Article 123(3) EPC according to the second option of G 1/99.

The amendment requested with the main and first auxiliary request, viz. replacement of the word "each" by "at least one" in feature (D4) of claim 1, is not a deletion of a limiting feature but a substitution of this feature. It does not overcome an objection raised with the appeal and it is not caused by a different evaluation by the Board. The objections against the claim in the version maintained by the Opposition Division can be overcome by amendments which do not extend the scope of protection (see point 5.1 below). The inadmissible amendment held allowable by the Opposition Division in its interlocutory decision relates to feature (E3) rather than to feature (D4)(see point 4 below), and this deficiency does not have the consequence that the patent would have to be revoked. Accordingly, the present amendment does not fulfil the preconditions defined in G 1/99 for justifying the exception.

The respondent's argument that the filing of fresh prior art (documents E7 and E8) by the sole appellant at the appeal stage should permit the respondent to retract amendments made by him before the Opposition Division is not accepted by the Board. It is true that G 1/99 (point 12 of the Reasons) states that the non-appealing proprietor deserves protection for reasons of equity when new facts have been introduced in appeal proceedings, and that the patent can exceptionally be amended in a way that offends the principle of prohibition of reformatio in peius. However, this is possible only if a limitation proves impossible (point 15 of the Reasons). In the present case, the appellant's objection based on the above-mentioned new documents, which was raised against the version maintained by the Opposition Division, does not require any limiting amendment of the claims. To deal with new prior art documents, the respondent either has to distinguish from it by argument or by making further restrictions to the claims upheld by the Opposition Division. The respondent may not in principle request another version of the patent during appeal proceedings, unless this version is a restriction of the maintained version (see G 1/99, Reasons 9.1). As shown below in point 5.2, the respondent's arguments regarding the new prior art have already convinced the Board, without the need for introduction of any further distinguishing amendments of the claims.

From the above it follows that the main and the first auxiliary requests are contrary to the principle of prohibition of reformation in peius and do not fulfil the conditions for an exception.

4. Second auxiliary request

The second auxiliary request corresponds to the version of the patent upheld by the Opposition Division. As objected to by the appellant and mentioned in the Board's communication, the phrase "a temperature controller (215) coupled to the power controller; the temperature controller which is adapted to individually control the conveyance of energy ..." (emphasis added) in the last paragraph of claim 1 is not clear since it does not make grammatical sense. Contrary to the respondent's assertion, the sense of such a distorted phrase is not "unassailably clear" and leaves the reader in doubt regarding its exact meaning. Accordingly, the second auxiliary request is not allowed since the amendment made to claim 1 at the opposition stage is not clear and does not meet the requirements of Article 84 EPC.

5. Third auxiliary request

5.1 Amendments

Claim 1 is based on claims 1 and 17 as granted, which correspond to original claims 18 and 36, respectively. The replacement of the words "which is" by the term "being" in the last paragraph of claim 1 overcomes the clarity objection discussed above (point 4) and does not add any technical information to the claim nor does it alter its scope. Accordingly, the Board is satisfied that the requirements of Article 123(2) and (3) EPC are met, and that the patent proprietor has not improved his position by this amendment.

In the description of the patent in suit (see for instance paragraphs [0036] to [0041]) it is clearly indicated that a plurality of emitters of ablating energy is foreseen, each of them in turn being provided with multiple temperature sensing elements, as shown in Figures 5 to 7 and required by claim 1. Accordingly, the description provides sufficient support for the claims within the meaning of Article 84 EPC, second sentence, and describes in detail one way of carrying out the invention claimed, as required by Rule 42(1)(e) EPC. Contrary to the appellant's assertion, it is not necessary that at least one of the drawings of the patent in suit actually depicts multiple emitters with multiple sensors.

5.2 Inventive step

5.2.1 For ease of reference, the feature denotation of claim 1 proposed by the respondent in his letter of 13 March 2009, will be used in the following:

(0) An ablating system for ablating body tissue, comprising:

(A) multiple emitters (30, 201, 202, 203) of ablating energy;

(B1) two or more temperature sensing elements (80, 208, 209, 210)

(B2) at each energy emitter

(B3) for measuring temperature at the energy emitter;

(C1) a power controller (230)

(C2) coupling a source of ablating energy to each energy emitter to convey ablating energy to the energy emitters;

(D1) a processing element (215)

(D2) which is adapted to periodically read the temperatures measured by each of the temperature sensing elements

(D3) for each energy emitter

(D4) and to select for each energy emitter the hottest one of the measured temperatures,

(D5) to compare the hottest one of the temperatures for each energy emitter to a desired temperature,

(D6) and is adapted to generate a signal individually for each energy emitter based upon the comparison wherein the desired temperature is established for all emitters, and

(E1) a temperature controller (215)

(E2) coupled to the power controller

(E3) the temperature controller being adapted to individually control the conveyance of energy to each energy emitter

(E4) based upon the signal for that energy emitter

(E5) to maintain the hottest temperature at all energy emitters essentially at the desired temperature during tissue ablation.

5.2.2 Document E7, which relates to the technical field of cardiac ablation and aims at precisely monitoring and controlling the emission of energy from the ablation electrode, represents the closest prior art. It discloses (see Figures 8A to 8C and the corresponding part of the description starting at page 20, line 24) an ablating system for ablating body tissue comprising all features of claim 1 with the exception of features (D4), (D5) and (E5).

Instead of selecting for each energy emitter 110, 112 the hottest one of the measured temperatures and comparing the hottest one of the temperatures for each energy emitter to a desired temperature as required by features (D4) and (D5), document E7 teaches a selection and comparison on the basis of an average value of the temperature (page 20, lines 28 to 33 and page 21, line 21). With respect to feature E5 it is to be noted that there is no teaching in document E7 that both emitters 110 and 112 are to be kept at the same (average) temperature. The sensors 94 in each emitter are averaged and displayed separately (page 20, penultimate paragraph and page 21, 5th paragraph). No specific advantages are indicated in document E7 for the use of multiple sensors and averaging. There is no hint to deviate from the concept of averaging and that the hottest temperature could be of any interest.

5.2.3 The temperature sensor providing the maximum temperature for a given emitter indicates that the corresponding region of the emitter is in most intimate contact with the tissue to be ablated, whereas those sensors providing lower temperatures are (more) exposed to convective cooling by the surrounding blood (see paragraph [0121] of the patent specification). Accordingly, the technical effect of the above-mentioned distinguishing features (D4) and (D5) with respect to document E7 is that the most representative temperature signal is used as set point for the temperature control system. Maintaining all emitters at this temperature (feature (E5)) yields an improved thermal control of the treatment site along the entire length of the ablating element (see paragraphs [0110] and [0126]).

5.2.4 The objective technical problem underlying the above-mentioned effects is to achieve a more accurate temperature control and thus a more effective ablation treatment. This problem is derivable from paragraph [0008] of the specification of the patent in suit.

5.2.5 The appellant's assertion that the solution according to claim 1 is obvious in view of the common general knowledge of the skilled person is not accepted by the Board. The appellant has failed to produce any evidence that the phenomenon of cooling resulting from contact of tissue ablation device temperature sensors with blood was taken into account by the skilled person before the priority date of the patent in suit. By recognising the significance of this phenomenon, i.e. that blood-cooling of certain temperature sensors could result in a distorted signal, not being representative of the temperature of the tissue to be ablated, the inventors of the present patent have in fact identified an important new factor to be taken into consideration in ablation device control. Taking further into account the rather opposite teaching of E7 (averaging vs. distinct use of an extreme value), the solution proposed by claim 1 cannot be regarded as obvious from E7 in view of the common general knowledge of the skilled person.

5.2.6 E3/E3T does not explicitly relate to an ablation device, but to devices for performing thermal therapy of "internal affected areas", e.g. the esophagus and other parts of the digestive tract (see paragraphs [0001], [0010] and [0046]), i.e. to a neighbouring field which would principally be taken into consideration by the skilled person. The range of working temperatures disclosed in E3T, e.g. 40ºC to 45ºC as mentioned in paragraph [37], lies within the lower part of the range of 40ºC to 90ºC indicated in paragraph [0123] of the patent specification as being suitable for cardiac ablation.

E3T teaches the use of the maximum temperature signal from a plurality sensor as set point for the temperature control system (see paragraphs [0038] and [0047]. The key objective, however, is to avoid burns or "fires" (see paragraphs [0005] and [0047]). By using the maximum temperature signal it is possible to assure that the maximum desired temperature (e.g. 45ºC as shown in Figure 17) is nowhere exceeded. In the patent in suit, on the other hand, the aim is to use the temperature signal most representative of intense tissue contact and to positively achieve the desired ablation temperature at all emitters (see point 5.2.3 supra).

In the device of E3T, the contact of the internal emitter 3 with the tissue to be treated is established by means of an inflatable balloon 6. Under these circumstances, the issue of certain regions of the emitter(s) being subject to convective cooling by surrounding blood, resulting in signals that are "too low" and not representative, plays no role. Accordingly, when starting from E7 and attempting to solve the above-mentioned technical problem, the skilled person would not have taken into consideration the teaching of E3/E3T. Moreover, the combination of E7 and E3T would not lead to the subject-matter of claim 1 since both documents fail to teach or suggest that the hottest temperature is to be maintained at all emitters essentially at the desired temperature, as required by feature (E5).

5.2.7 Document E8 is very similar to E7 and comprises the same set of drawings. Its teaching does not go beyond that of E7.

5.2.8 Document E1 relates to an ablation device (see abstract, first sentence, and column 4, lines 39 to 43). However, it is more remote from the invention than E7 in that it only teaches either a single emitter 27 with multiple sensors 24 (Figures 1 to 3), or multiple emitters 40 each having a single sensor 42 (Figure 5), but fails to disclose multiple emitters each having multiple sensors, as required by features (A), (B1) and (B2) of claim 1. The document is also silent with respect to using the hottest temperature as a set point for the control system. Just as in document E3, local overheating is to be avoided (see column 4, lines 60 to 64). Furthermore, E1 also relates to a balloon-expandable system (column 2, lines 12 to 15) and fails to address the issue of blood-contact cooling. Accordingly, when taking E1 as a starting point instead of E7, the subject-matter of claim 1 is not rendered obvious either.

The mere fact that the proprietor, when drafting the patent application, cited document E6 (cf. paragraph [0008] of the patent specification), which discloses an ablation device with multiple emitters, and might have been aware of the thus achievable benefit of a more uniform temperature distribution along the abating element, does not change this finding.

5.2.9 From the above it follows that the subject-matter of claim 1 of the third auxiliary request is not obvious and involves an inventive step within the meaning of Article 56 EPC.