Alleviating pain during extracoporal lithotripsy

• US 4,662,375 A
• Filed: 06/24/1985
• Issued: 05/05/1987
• Est. Priority Date: 04/04/1985
• Status: Expired due to Fees

• Current Assignee: Dornier System GmbH
• Original Assignee: Dornier System GmbH
• Inventors: Heine, Gerold, Marlinghaus, Ernst, Wess, Othmar, Hepp, Wolfgang
• Primary Examiner(s): Crowder, Clifford D.
• Application Number:
  US06/747,954
• Time in Patent Office: 680 Days
• Field of Search: 128/804, 128/328, 128/24 A, 128/660
• US Class Current: 601/4
• CPC Class Codes: A61B 17/225 for extracorporeal shock wave lithotripsy [ESWL], e.g. by using ultrasonic waves
• CPC Class Codes: A61B 17/2251 characterised by coupling elements between the apparatus, e.g. shock wave apparatus or locating means, and the patient, e.g. details of bags, pressure control of bag on patient
• CPC Class Codes: G10K 11/04 Acoustic filters ; Acoustic resonators

Abstract

In extracorporal lithotripsy a shock wave that is focussed on a concrement is followed by a pain producing pressure wave. This wave is filtered by means of a membrane bulging inwardly into the focussing chamber, closing the same and having a thickness smaller than the predominant wave length of the shock wave.

Claims

1. In equipment for extracorporal lithotripsy of nonanesthesized patients and including a rotationally-symmetrical, ellipsoidal focusing chamber having two focal points there being a shock wave generating source in one of the focal points, the focusing chamber being positionable so that the other focal point coincides with a concrement in a patient, which concrement is to be comminuted by shock waves, there being a water coupling path between the focusing chamber on one hand and the patient on the other hand the improvement of avoiding and attenuating pain, comprising:

a spherically calotte shaped membrane made of a material with a high coefficient of elasticity and being clamped against and closing the focusing chamber and inwardly bulging towards the shock wave generating source, the wall thickness of the membrane being significantly shorter than the wavelength of a shock wave being produced.

2. The improvement as in claim 1 wherein the cross section of said membrane is an arch so that pressure loads will produce compression stress in the membrane.

3. The improvement as in claim 1 said membrane being configured so that its center of curvature coincides with said other focal point.

4. The improvement as in claim 1 wherein said calotte membrane is clamped to the edge of the focusing chamber under utilization of a ring and tension screws for fastening the ring to the focusing chamber.

5. The membrane as in claim 1 being made of steel.

6. The membrane as in claim 1 being made of a Cu-Be alloy.

7. The membrane as in claim 1 being made of a carbon fiber reinforced synthetic.

8. The improvement as in claim 1 including means for grounding for obtaining nonconduction and conductive separation between the interior of the focusing chamber containing the electrodes and any part that is in physical contact with a patient.

9. The membrane as in claim 1 having at least on one side a facet structure.

10. The membrane as in claim 1 having a center thinner than the remainder of the membrane, the wall thickness continuously decreasing towards the center.

11. The membrane as in claim 1 being thinner in the center as well as in the edges as compared with the remainder of the membrane.

12. The improvement as in claim 1 and including an elastically deformable element in the vicinity of said source, the element being situated in recesses in the wall of the focusing chamber.

13. The improvement as in claim 1 there being a water inlet and a water discharge for the focusing chamber being situated in the vicinity of said membrane.