Method and device for locating and mapping nerves

• US 6,535,759 B1
• Filed: 10/20/2000
• Issued: 03/18/2003
• Est. Priority Date: 04/30/1999
• Status: Expired due to Fees

• Current Assignee: Blue Torch Medical Technologies, Inc.
• Original Assignee: Blue Torch Medical Technologies, Inc.
• Inventors: Epstein, Richard, Abichaker, David G., Rego, Richard P.
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US09/692,418
• Time in Patent Office: 879 Days
• Field of Search: 600/547, 600/548, 600/554, 600/555, 604/116, 606/32, 607/116
• US Class Current: 600/547
• CPC Class Codes: A61B 5/4893 Nerves
• CPC Class Codes: A61N 1/0502 Skin piercing electrodes
• CPC Class Codes: A61N 1/36014 External stimulators, e.g. with patch electrodes external pacemakers A61N1/3625
• CPC Class Codes: A61N 1/36017 with leads or electrodes penetrating the skin

Abstract

The present application discloses a method and device for locating and mapping the cavernosal nerve bundle by electro-stimulation to enable safe and effective implantation of radioactive seeds for prostate brachytherapy. By locating and mapping the cavernosal nerve bundle prior to seed implantation, the brachytherapist can make intra-operative decisions to avoid mechanical and radiational injury to the nerve which results in impotency or other prostate-Urethral complications. The device of the invention takes the form of an automated closed-looped electro-stimulating system having a handle for manipulating the device, a stimulating tip for applying an electro-stimulus to a tissue site, a control unit to activate and terminate application of the electro-stimulus and to interpret a tumescence response, a sensor for detecting and measuring a tumescence response, a patient ground return, and a display monitor to indicate the nature, stability and strength of the tumescence response to the brachytherapist. If the control unit concludes that the applied electro-stimulus failed to evoke a tumescence response in excess of a pre-determined baseline and that the tissue lacks cavernosal nerve bundle fibers, radioactive seeds can be implanted in the prostate through the stimulating tip which also serves as a brachytherapy seed implantation needle. Alternatively, the coordinates of the tissue site can be mapped on the perineal grid or on a pre-plan grid for later seed implantation.

Claims

1. A device for locating the cavernosal nerve bundle to avoid injury during application of minimally invasive and non-invasive prostate cancer therapies, comprising:

means for detecting and measuring a tumescence response signal and a change in the tumescence response signal evoked by application of an electro-stimulus to the cavemosal nerve;

means for analyzing the tumescence response signal provided by said detecting and measuring means to determine its stability;

means for applying an electro-stimulus to an area of tissue; and

means for interpreting a change in the signal evoked by application of the electro-stimulus to the cavernosal nerve to determine the location of the nerve;

wherein said stimulus applying means is a brachytherapy needle comprising means for delivering a therapeutic agent to tissue.

2. The device of claim 1, wherein said stimulus applying means comprises a removable cannula with a hollow lumen sized to receive a pre-loaded needle containing radioactive seeds.

3. The device of claim 1, wherein said means for detecting and measuring a tumescence response signal comprises fluid-filled distensible tubing.

4. A kit for locating and mapping a nerve to avoid injuring the nerve during application of therapy, the kit comprising:

a device for locating a nerve using electro-stimulation, said device comprising;

means for detecting and measuring a response signal and a change in the response signal evoked by application of an electro-stimulus to the nerve;

means for analyzing the response signal provided by said detecting and measuring means to determine its stability;

means for applying an electro-stimulus to an area of tissue; and

means for interpreting a change in the signal evoked by application of the electro-stimulus to the nerve to determine the location of the nerve; and

a grid for mapping coordinates corresponding to tissue sites;

wherein said nerve is the cavemosal nerve and said response signal corresponds to penile tumescence.

5. The kit of claim 4, wherein said means for applying an electro-stimulus to an area of tissue comprises a removable array of electrodes to determine the location of the nerve to avoid injuring the nerve during radical prostatectomy.

6. The kit of claim 4, wherein said means for applying an electro-stimulus to an area of tissue comprises a removable needle for applying an electro-stimulus to the tissue area and for administering minimally invasive prostate cancer therapy through the perineum of a human patient.

7. The kit of claim 6, wherein said needle comprises a brachytherapy seed implantation needle for applying brachytherapy to the prostate.

8. The kit of claim 6, wherein said needle comprises a cryosurgical needle for applying cryosurgery to the prostate.

9. The kit of claim 6, wherein said needle comprises a hollow lumen sized to receive a magazine of radioactive brachytherapy seeds.

10. The kit of claim 4, wherein said response detecting and measuring means comprises distensible fluid-filled tubing.

11. The kit of claim 6, wherein said grid comprises a plurality of bores which define coordinates on said grid and said grid comprises structure for positioning said grid proximate the perineum.

12. The kit of claim 11, wherein said bores of said grid correspond to tissue coordinates of the prostate.

13. A method for locating and mapping cavemosal nerve fibers to avoid injuring the nerve fibers during application of prostate cancer therapy, comprising the steps of:

a) detecting and measuring a tumescence response signal from the cavernosal nerve;

b) determining the stability of the tumescence response signal and characterizing it as stable or unstable;

c) applying an electro-stimulus to a tissue site believed to contain the cavernosal nerve fibers if the tumescence response signal has been characterized as stable;

d) detecting and measuring any change in the tumescence response signal evoked by application of the electro-stimulus;

e) interpreting any change in the tumescence response signal evoked by application of the electro-stimulus;

f) determining if the tissue site contains cavernosal nerve fibers; and

g) applying prostate cancer therapy to the tissue site if it has been determined that the tissue site does not contain cavernosal nerve fibers.