Surgery – Instruments – Means for concretion removal
Reexamination Certificate
2000-02-17
2001-07-17
Philogene, Pedro (Department: 3732)
Surgery
Instruments
Means for concretion removal
Reexamination Certificate
active
06261298
ABSTRACT:
DESCRIPTION
1. Field of the Invention
The present invention relates to a device for concrement destruction or crushing in accordance with the introductory clause of Patent claim
1
.
2. Prior Art
Devices for intracorporeal operation for concrement destruction or crushing have been commonly known. Such devices are used, for instance, as so-called lithotripters in medicine for destroying concrements such as renal calculi, urinary calculi or the like by short surge pulses of a probe introduced into the human body, or to comminute them to such a size that they can be discharged via the urinary tract.
A device which the wording of the introductory clause of Patent claim
1
starts out from is described in the document WO 96/33661. That device comprises an elongate probe adapted for being introduced into the human body, particularly via the ureter. A lever bears against the proximal end of the probe, which performs a rotating movement for accelerating the probe to perform, in its entirety, a translational movement at a sufficient rate such that when the distal end of the probe hits the concrement the latter will be crushed. The lever is driven, for instance, by means of an impact body which hits the lever with a high speed for driving it to perform a high-speed rotational movement.
From the European Patent EP 0 317 507 B1 an apparently similar device for concrement crushing is known. In that device a projectile hits the proximal interface of a wave It is intended that the hitting projectile should excite shock waves in the wave guide which are meant to result in a displacement of the distal interface of the wave guide.
In distinction from the device known from the European Patent EP 0 317 507 B1, the device known from the document WO 96133661, wherein merely or mainly shock waves or compression waves are excited in the wave guide, presents the following advantage: as with the device known from WO 96/33661 the probe is displaced as one unit the entire mass of the probe contributes to the kinetic energy of the probe. In the device known from the European Patent EP 0 317 507 B1, by contrast, only that fraction of the entire mass contributes to the kinetic energy which is influenced by the compression wave “migrating therethrough”. As a result, the “effective kinetic energy” is much higher in the device known from WO 96/33661, where the probe is moved as a complete unit, so that an excellent crushing result is achieved.
The reason for the translational movement of the probe as a single unit, instead of the excitation of a shock wave or a compression wave, resides in the use of a lever:
The lever produces the effect of a transformation element achieving a low-pass effect. Due to this low-pass effect the kinetic energy of the impact body is transformed by the lever, which serves as transformation element, in such a way that substantially only a translational or uniform straight movement of the probe is achieved with the aforementioned high kinetic energy, without a therapeutically effective compression wave fraction.
BRIEF DESCRIPTION OF THE INVENTION
The present invention starts out from the finding that with an optimisation of the ratio of the distance of the bearing surface centre of the lever, which serves as transformation element in a home position on the proximal end surface of the probe, from the rotational axis, to the distance of the centre of the impact area of the impact body on the lever from the rotational axis it is possible to achieve a translational speed as high as possible at an optimum kinetic energy of the probe.
In particular, the present invention is based on the finding that in the device known from WO 96/33661 the lever ratios—as shown in the drawing—are not selected at an optimum.
The present invention is therefore based on the problem of proposing a device serving for mechanical concrement crushing, wherein the probe hits on the concrement at the maximum speed possible and wherein a maximum amount possible of kinetic energy of the impact body is transferred to the probe.
In accordance wit the invention, this problem is solved with the provisions that the distance of the centre of the bearing surface of the lever in its home position on the proximal end surface of the probe, from the rotational axis is smaller and particularly definitely smaller than the distance of the centre of the impact area of the impact body on the lever from the rotational axis, and that the ratio of the distance is so selected that the probe will achieve a maximum translational speed.
This means that the first impact point is located between the rotational axis and a freely mobile end of the lever arm, and that the probe is acted upon in particular by another area of the lever element rather than by the centre of the lever element. Whereas in the conventional lever design and lever arrangement, which are made in consideration of the cylindrical structure of the housing, the first impact point is provided on the freely mobile lever end and the second impact point is located precisely in the middle between the two lever ends, the inventive asymmetric position of the impact points permits the matching of the energy transfer from the impact body to the probe with the involved masses of the impact body, the lever and the probe, and makes it possible that losses in energy transfer, which are caused by the lever mechanism, will be largely avoided.
The lever may not only be a single-arm lever but fundamentally the most different types of transfer or transformation elements such as the arrangements of several levers may be selected which, due to different distances between the impact points and the rotational axes, i.e. on account of different impact radii, allow for matching the lever action with a maximum energy transfer to the impact probe.
With the optional application of a single-arm lever it is preferred that the distance of the centre of the bearing surface of the lever on the proximal end surface of the probe is wider than the distance between the centre of gravity of the lever and the rotational axis.
In particular, the rotational axis may be provided for displacement along the longitudinal axis of the lever in its home position so that the lever action can be adjusted. For an optimisation of the energy transfer not only in the zone of the interior of the housing but also between the distal probe end and the concrement a regulation of the lateral position of the lever element is expedient when the energy transfer for crushing concrements of different sizes should be harmonised with the respective concrement mass.
In an alternative or additionally it is possible that the proximal end of the impact probe and the impact unit are provided for lateral displacement relative to each other so as to permit a regulation of the lever action. Whilst a displacement of the lever varies both impact radii it is possible, in correspondence with this potential configuration, to optimise one of the impact radii independently of the other radius. In this context, the term “displacement” is to be understood here to denote any movement which results in a lateral dislocation of the probe and the impact unit, in opposition to the literal meaning otherwise common; for instance, a rotation of the impact unit or of the rear part of the housing, respectively, about an axis extending outside the centre of the housing or the proximal probe end, or any other adjusting mechanism may result in a lateral approximation of the impact unit and the impact probe (or their extensions on the housing side, respectively).
It is moreover possible that the lever element has a varying cross-section over its length. With this provision it is possible—either as an alternative of or in addition to the aforementioned provisions—to achieve a further matching of the energy transfer to the lever and from the lever to the probe.
Particularly when the mass of the lever is definitely smaller than the mass of the impact body and the mass of the lever corresponds roughly to half the mass of the impact body or less and the mass of the probe corr
Irion Klaus
Leibersperger Wolfgang
Karl Storz-GmbH & Co. KG
Philogene Pedro
St. Onge Steward Johnston & Reens LLC
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