Electrosurgical device with improved visibility

• US 7,593,778 B2
• Filed: 03/15/2005
• Issued: 09/22/2009
• Est. Priority Date: 03/07/2003
• Status: Expired due to Term

• Current Assignee: Avent Incorporated (Avanos Medical, Inc.)
• Original Assignee: Baylis Medical Company Inc. (Boston Scientific Corporation)
• Inventors: Shah, Krishan, Chandran, Subashini
• Primary Examiner(s): Layno; Carl H
• Assistant Examiner(s): Gedeon; Brian T
• Application Number:
  US11/079,318
• Publication Number:
  US 20050159797A1
• Time in Patent Office: 1,652 Days
• Field of Search: 128/898, 607 96-117
• US Class Current: 607/116
• CPC Class Codes: A61B 18/1477 Needle-like probes
• CPC Class Codes: A61B 2090/3966 Radiopaque markers visible in an X-ray image
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: A61N 1/06 for high-frequency therapy
• CPC Class Codes: A61N 1/36017 with leads or electrodes penetrating the skin
• CPC Class Codes: A61N 1/36021 for treatment of pain
• CPC Class Codes: A61N 1/40 Applying electric fields by inductive or capacitive coupling microwave apparatus A61N5/00; Applying radio-frequency signals

Abstract

A method and apparatus are disclosed for improving accuracy of placement of a cannula during delivery of electrical energy proximate to bodily tissue, e.g. neural structures. The apparatus optionally includes a cannula operable to deliver electrical current where a portion of the cannula is electrically insulated and a portion of the cannula is exposed and electrically conductive. The cannula further includes a radiopaque marker to identify a specific portion of the cannula, for example to differentiate the electrically insulated region from the electrically exposed region, by allowing it to be more clearly delineated using fluoroscopy or other radiographic imaging techniques. The radiopaque marker is optionally tapered in order to reduce the force required to insert a cannula comprising a radiopaque marker into the patient'"'"'s body.

Claims

1. A radiopaque cannula for Insertion into a patient'"'"'s body, the cannula comprising:

a radiopaque and electrically conductive elongate member of a fixed length, having a proximal end and a distal end and defining a lumen therebetween, the elongate member including an electrically exposed region and an electrically Insulated region, an outer diameter of the cannula at the electrically Insulated region being larger than an outer diameter of the cannula at the electrically exposed region;

a radiopaque marker located adjacent a distal end of the insulated region where the outer diameter of the cannula varies from the larger outer diameter of the insulated region to the smaller diameter of the exposed region, a distal end of the marker being tapered to provide a transition from the smaller outer diameter of the electrically exposed region to the larger outer diameter of the electrically insulated region; and

the radiopaque marker being visible under radiographic imaging for distinguishing the exposed region from the insulated region.

2. The cannula of claim 1, wherein said radiopaque marker comprises a material selected from the group consisting of platinum, iridium, gold, silver, tantalum and alloys thereof.

3. The cannula of claim 1, wherein said cannula comprises material selected from the group consisting of stainless steel, titanium and nitinol.

4. The cannula of claim 1, wherein at least a portion of said distal end of said elongate member is bent.

5. The cannula of claim 1, wherein said distal end of said elongate member defines an aperture in communication with said lumen.

6. The cannula of claim 1, further comprising a lateral aperture in communication with said lumen.

7. The cannula of claim 1, further comprising at least one marker selected from the group consisting of visual markers and tactile markers.

8. The cannula of claim 1, wherein said cannula is operable to connect to an energy source.

9. The cannula of claim 1, further comprising a stylet, said stylet being insertable into said lumen.

10. The cannula of claim 9, wherein said stylet comprises a radiopaque marker.

11. The cannula of claim 1 wherein the electrically insulated region comprises a coating of an electrically insulating material disposed external to the elongate member along at least a portion of the elongate member.

12. The cannula of claim 1 wherein the marker is affixed to the elongate member by a laser weld.

13. The cannula of claim 1 wherein the radiopaque marker comprises a band that completely circumscribes the elongate member.

14. A cannula for insertion into a patient'"'"'s body, said cannula comprising:

an electrically conductive radiopaque elongate member of a fixed length, the elongate member comprising an electrically insulated region and an electrically exposed region, an outer diameter of the cannula at the insulated region being larger than an outer diameter of the cannula at the exposed region; and

a means for improving radiographic visualization of said elongate member;

said means for improving radiographic visualization being external to and disposed along an intermediate position of said elongate member and a distal end of said means for improving radiographic visualization being tapered to transition from the outer diameter of the cannula at the insulated region to the outer diameter of the cannula at the exposed region.

15. A system for delivering energy to a patient'"'"'s body, said system comprising:

an energy source;

a radiopaque cannula comprising an electrically conductive radiopaque elongate member of a fixed length, the elongate member comprising an electrically insulated region, an electrically exposed region and a radiopaque marker for distinguishing the insulated region from the exposed region using radiographic imaging techniques, an outer diameter of the cannula at the insulated region being larger than an outer diameter of the cannula at the exposed region, the marker being external to and disposed along an intermediate position of the elongate member adjacent a distal end of the insulated region, and a distal end of the marker being tapered to transition from the outer diameter of the cannula at the insulated region to the outer diameter of the cannula at the exposed region;

a means of delivering energy from said energy source to said cannula; and

a reference electrode.

16. A method for treating pain by delivering energy to a patient'"'"'s body, comprising the steps of:

(i) providing an electrically conductive radiopaque cannula of a fixed length comprising an electrically insulated region, an electrically exposed region and a radiopaque marker located at a proximal end of the exposed region for distinguishing the insulated region from the exposed region, the marker being external to and disposed along an intermediate position of the cannula, a distal end of the marker being tapered to thereby reduce a force required to insert said cannula into said patient'"'"'s body;

(ii) identifying the radiopaque marker, distinguishing the insulated region from the exposed region and positioning the proximal end to locate said electronically exposed region proximate a region of tissue to be treated; and

(iii) delivering energy through the cannula to said region of tissue to be treated;

wherein the energy is delivered to relieve pain.

17. The method of claim 16, wherein the tissue to be treated is neural tissue.

18. The method of claim 17, wherein the neural tissue is located proximate to or within a facet joint of a patient'"'"'s spine.