# US 8,150,506 B2 · Methods and devices for differentiating between tissue types

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- Number: US 8,150,506 B2
- Document ID: US8150506B2
- Status: Granted
- Kind: B2
- Application number: 12/440,767
- Filed: 2007-09-12
- Published: 2010-03-11
- Granted: 2012-04-03
- Earliest claimed: 2006-09-12
- Assignees: University of Florida Research Foundation, Inc.
- Inventors: Shalesh Kaushal; Michael Darnall Furman; Jennifer Delight Simonotto; Abraham Miliotis
- Web page: https://patentgrep.com/patent/US8150506B2

## CPC

- A61F 9/00736: {Instruments for removal of intra-ocular material or intra-ocular injection, e.g. cataract instruments (A61F9/008 takes precedence)}
- A61B 5/053: Measuring electrical impedance or conductance of a portion of the body
- A61B 2017/00026: {Conductivity or impedance, e.g. of tissue}
- A61B 2017/00115: {with audible or visual output}
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

The subject invention utilizes the characteristics of in vivo tissue impedances to provide an embodiment of a retinal rake capable of providing a visible and/or preferably an audible signal to a surgeon that more clearly indicates which type of tissue(s) is in contact with the retinal rake. A preferred embodiment comprises a handheld, battery operated retinal rake having two electrodes, wherein at least one electrode is the modified retinal rake. Upon contact with different optical tissues, e.g., epiretinal membranes, retinal tissue, vitreous humor, etc., the electrodes detect varying impedances which are translated by onboard circuitry into various signals that indicate what type of tissue, fluid, structure, etc. is in contact with the retinal rake.

## Claims

### Claim 1

A retinal rake comprising:
an at least one first electrode;
an at least one second electrode for contacting tissue;
a circuit operably connected to the first and second electrode and configured to receive one or more impedance signals generated between the first and second electrode when said second electrode contacts a tissue, identify a level of impedance signal, and emit an observable signal indicative of the level of impedance signal,
wherein the retinal rake comprises a shank to which is attached, at one end, a plurality of tines, and wherein the at least one first electrode is affixed to the shank and the at least one second electrode is located at or near the tines.

### Claim 2 (depends on 1)

The retinal rake, according to claim 1, wherein the second electrode comprises at least a portion of the tines of the retinal rake.

### Claim 3

A method for treating or removing tissue from the eye wherein said method utilizes a retinal rake comprising:
an at least one first electrode;
an at least one second electrode for contacting tissue;
a circuit operably connected to the first and second electrode and configured to receive one or more impedance signals generated between the first and second electrode when said second electrode contacts a tissue, identify the level of impedance signal, and emit one or more observable signals indicative of one or more levels of impedance signal,
wherein the retinal rake comprises a shank to which is attached, at one end, a plurality of tines, and wherein the at least one first electrode is affixed to the shank and the at least one second electrode is located at or near the tines, and
wherein said method comprises inserting the retinal rake into a site in the eye where tissue is to be removed or treated, using the retinal rake to treat or remove tissue while simultaneously observing the signals emitted by the retinal rake and adjusting a position of the retinal rake in response to the emitted signals.

### Claim 4 (depends on 3)

The method, according to claim 3, wherein said method is used to remove tissue.

### Claim 5 (depends on 4)

The method, according to claim 4, wherein the retinal rake removes epiretinal tissue.

### Claim 6 (depends on 3)

The method, according to claim 3, wherein the retinal rake delivers a medicament.

### Claim 7 (depends on 6)

The method, according to claim 6, wherein the medicament is used to destroy unwanted tissue.

### Claim 8 (depends on 3)

The method, according to claim 3, wherein the second electrode comprises at least a portion of the tines of the retinal rake.