Intellectual Property Enterprise Court

IP-2024-000024 - [2025] EWHC 492 (IPEC)

Fecha: 07-Mar-2025

Construction

Construction

Claim 1 – sheath lumen and the side arm lumen have ‘the same’ diameter

26.

Integer 10 requires ‘said sheath having a lumen which is the same diameter as a lumen of said side arm and if present as a lumen of said accessory side arm’. The optional accessory side arm can be left to one side. The issue is what ‘the same diameter’ means, as between the sheath and the main side arm.

27.

Paragraph [0020] of the specification states:

‘In one embodiment, the diameter of the lumen 53 of the side arm 50 is up to 20% smaller than the diameter of the lumen 33, 43 of the proximal 30 and the distal sheath 40. In another embodiment, the diameter of the lumen 53 of the side arm 50 has a diameter which is the same or up to 20% larger than the diameter of the lumen 33, 43 of the proximal 30 and the distal sheath 40. According to the present invention, the diameter of the lumen 53 of the side arm 50 is the same as the diameter of the lumen of the sheath 23, 33, 43 to facilitate the efficient evacuation of stones, stone fragments or other foreign bodies.’

28.

Paragraph [0015] says:

‘One important feature of the current invention is a sheath 20 that has a side arm 50 that has an identical or nearly identical luminal circumference.’

29.

The same paragraph says more about this, explaining the reason for identical or nearly identical luminal circumferences (and therefore diameters):

‘When the stone fragments are larger, but still small enough to enter the sheath lumen 23, the endoscope can be withdrawn to a location that is just proximal to the distal end 52 of the side arm 50. … With the scope in this position, the sheath 20 and the side arm lumens now have a similar caliber channel with the side port channel equal or slightly larger than the sheath channel. The stone fragments or foreign body have an unimpeded evacuation route. This allows a continuous evacuation channel for the stone fragments to reach the collection container 80.’

30.

Well Lead submitted that the first two embodiments referred to in paragraph [0020] must be taken to be embodiments of the invention and therefore the same lumen diameter means that the diameter of the side arm lumen may be + 20% the dimension of the sheath lumen.

31.

The difficulty with this submission is that the word ‘embodiment’ is used in confusingly different ways in the specification. Sometimes the description speaks of an ‘embodiment of the present invention’, which is clear. Elsewhere it refers to an ‘embodiment of the disclosure not forming part of the present invention’, equally clear. But there is also discussion of matter which is either an ‘embodiment of the disclosure’, just an ‘embodiment’ or a ‘preferred embodiment’.

32.

Well Lead referred to the current Guidelines for Examination in the EPO (March 2024), Part F, Chapter IV-17, which includes this at 4.3:

‘An inconsistency between the description and the claims cannot be removed by introducing at the beginning of the description a generic statement such as "embodiments not falling under the scope of the appended claims are to be considered merely as examples suitable for understanding the invention" without indicating which parts of the description are no longer covered. To remove the inconsistency, such a statement has to refer to specific embodiments (e.g. "Embodiments X and Y are not encompassed by the wording of the claims but are considered as useful for understanding the invention").

The terms "disclosure", "example", "aspect" or similar, on their own, do not necessarily imply that what follows is not encompassed by an independent claim. Unambiguous expressions have to be adopted to mark an inconsistent embodiment (e.g. by adding "not encompassed by the wording of the claims", "not according to the claimed invention" or "outside the subject-matter of the claims") instead of merely replacing the terms "embodiment" or "invention" by one of the aforementioned terms.

As long as the resulting text of the description does not present conflicting information to the reader, an inconsistent embodiment may also be remedied by ensuring that it is not referred to as being "according to the invention" throughout the description and by complementing the reference to it with an explicit statement to the effect that it is retained due to being useful for understanding the invention (e.g. "embodiment useful for understanding the invention", "comparative example from background art".’

33.

I do not know that the Guidelines current during the period of prosecution of the Patent were the same as the current version. Even if they were, the Guidelines do not advance matters much.

34.

My impression is that during prosecution some effort was made to make the specification consistent with the claim, but not overmuch. By comparing the Patent with the application for the Patent it appears that the words ‘according to the present invention’ were added to paragraph [0020] and placed before the words ‘the diameter of the lumen of the side arm is the same as the lumen of the sheath’. It suggests that the draftsperson wished at this stage to clarify that having the diameters the same was central to the invention as finally settled upon.

35.

It is possible that at the time the examiner took a relaxed view about other parts of the specification: provided that no embodiment in which the respective lumen sizes are not substantially the same was expressly stated to be an embodiment according to the invention, any references simply to ‘an embodiment’ or ‘an embodiment of the disclosure’ where such embodiments were, by the time of grant, no longer part of the invention, could be left alone.

36.

Taking a purposive approach to this point of construction does not help much. The only identified purpose in having the two diameters the same or about the same is to facilitate the efficient evacuation of stones, fragments or foreign bodies. Neither of the experts in this case has expertise in fluid dynamics such as to confirm that a close similarity in diameters is necessary for that purpose. Nor would the skilled person. It is to be noted, though, that this stated purpose is in a sentence within paragraph [0020] which says that the lumen diameters are the same ‘according to the invention’.

37.

CJ Medical submitted that ‘the same’ in integer 10 of claim 1 should be given its natural meaning, subject to some limited leeway indicated in paragraph [0015], such as + 5% manufacturing tolerance.

38.

The words ‘the same as’ in claim 1 are, as used in the claim itself, clear and not ambiguous. They are consistent with a statement in the one sentence of paragraph [0020] which explicitly refers to what is covered by the invention and are also consistent with the words of paragraph [0015], again unambiguously referring to the claimed invention.

39.

In my view the skilled reader of the Patent would have understood that ‘the same’ means what it says, subject to a limited tolerance. It seems to me that a manufacturing tolerance of + 5% is probably about right.

40.

In the patent specification, references to an ‘embodiment of the disclosure’ or to ‘an embodiment’ are not to be taken as embodiments of the invention as finally settled upon by the patentee.