Method for monitoring viability of tissue flaps

• US 7,657,293 B2
• Filed: 09/08/2005
• Issued: 02/02/2010
• Est. Priority Date: 09/08/2005
• Status: Active Grant

• Current Assignee: ViOptix, Inc.
• Original Assignee: ViOptix, Inc.
• Inventors: Mao, Jian-Min, Lash, Robert E.
• Primary Examiner(s): Nasser; Robert L
• Assistant Examiner(s): D'ANGELO, MICHAEL J
• Application Number:
  US11/162,380
• Publication Number:
  US 20070051379A1
• Time in Patent Office: 1,608 Days
• Field of Search: 600323-340, 600485-504, 600473-481, 600/483, 600/36, 606/131
• US Class Current: 600/340
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/413 Monitoring transplanted tissue or organ, e.g. for possible rejection reactions after a transplant
• CPC Class Codes: A61B 5/4312 Breast evaluation or disorder diagnosis A61B5/0091 takes precedence
• CPC Class Codes: A61B 5/4848 Monitoring or testing the effects of treatment, e.g. of medication

Abstract

Methods and apparatus for assessing the viability of tissue such as flap tissue are disclosed. According to one aspect of the present invention, a method for assessing the viability of flap tissue includes obtaining an oxygen saturation level associated with a first location on the flap tissue, determining whether the oxygen saturation level is less than a first level, and identifying the first location as having a poor blood supply if the oxygen saturation level is less than the first level.

Claims

1. A method for assessing viability of flap tissue, the method comprising:

placing a sensor head of an optical imaging system in contact with the flap tissue at a first location, wherein the sensor head causes light to be reflected off of the flap tissue to identify an oxygen saturation level;

obtaining the oxygen saturation level associated with the first location on the flap tissue;

determining whether the oxygen saturation level is less than a first level; and

identifying the first location as having a poor blood supply if it is determined that the oxygen saturation level is less than the first level,

wherein the optical imaging system comprises;

a probe comprising;

a connection interface, the connection interface being adapted to allow the probe to be coupled to a plurality of light sources and at least one photodetector, wherein the light sources and the photodetector are external to the probe; and

the sensor head comprising a first source fiber, a second source fiber, and a first detector fiber, the first source fiber and the second source fiber being arranged to be coupled to the plurality of light sources via the connection interface, and the first detector fiber being arranged to be coupled to the photodetector via the connection interface; and

a beam combiner, external to the probe, coupled to the first source fiber and the plurality of light sources via the connection interface.

2. The method of claim 1 wherein the first level is approximately 50 percent oxygen saturation level, wherein the percent oxygen saturation level is a percentage of hemoglobin that is bound to oxygen.

3. The method of claim 1 further including:

trimming the flap tissue at the first location if the first location is identified as having the poor blood supply.

4. The method of claim 1, wherein the sensor head includes a first row of two source fibers and a second row of two detector fibers and wherein the first row of two source fibers is not in-line with the second row of two detector fibers.

5. The method of claim 4 wherein the first row is parallel to the second row.

6. The method of claim 5 wherein a first distance between a first source fiber of the first row and a second source fiber of the first row is the same as a second distance between a first detector fiber of the second row and a second detector fiber of the second row.

7. The method of claim 5 wherein a first distance between a first source fiber of the first row and a second source fiber of the first row is not the same as a second distance between a first detector fiber of the second row and a second detector fiber of the second row.

8. The method of claim 1, wherein the sensor head includes a first row having a first source fiber and a second source fiber and a second row having a first detector fiber and a second detector fiber and the first source fiber is arranged nonsymmetrically with respect to the second source fiber, first detector fiber, and second detector fiber.

9. A method for characterizing an artery associated with flap tissue, the artery being arranged to provide blood to the flap tissue, the method comprising:

placing a sensor head of an optical imaging system in contact with the flap tissue at a first location, wherein the sensor head causes light to be reflected off of the flap tissue to identify a first oxygen saturation level and a second oxygen saturation level;

identifying the first oxygen saturation level associated with the flap tissue;

inhibiting a flow of blood through the artery;

identifying the second oxygen saturation level associated with the flap tissue after inhibiting the flow of blood through the artery;

determining whether the second oxygen saturation level is significantly different from the first oxygen saturation level; and

designating the artery as providing significant blood to the flap tissue if it is determined that the second oxygen saturation level is significantly different from the first oxygen saturation level,

wherein the optical imaging system comprises;

a probe comprising;

a connection interface, the connection interface being adapted to allow the probe to be coupled to a plurality of light sources and at least one photodetector, wherein the light sources and the photodetector are external to the probe; and

the sensor head comprising a first source fiber, a second source fiber, and a first detector fiber, the first source fiber and the second source fiber being arranged to be coupled to the plurality of light sources via the connection interface, and the first detector fiber being arranged to be coupled to the photodetector via the connection interface; and

a beam combiner, external to the probe, coupled to the first source fiber and the plurality of light sources via the connection interface.

10. The method of claim 9 further including:

designating the artery as providing insignificant blood to the flap tissue if it is determined that the second oxygen saturation level is not significantly different from the first oxygen saturation level.

11. The method of claim 9 wherein inhibiting the flow of blood through the artery includes clamping the artery to cut off a supply of blood through the artery.

12. The method of claim 9, wherein the sensor head includes a first row of two source fibers and a second row of two detector fibers and wherein the first row of two source fibers is not in-line with the second row of two detector fibers.

13. The method of claim 12 wherein the first row is parallel to the second row.

14. The method of claim 13 wherein a first distance between a first source fiber of the first row and a second source fiber of the first row is the same as a second distance between a first detector fiber of the second row and a second detector fiber of the second row.

15. The method of claim 13 wherein a first distance between a first source fiber of the first row and a second source fiber of the first row is not the same as a second distance between a first detector fiber of the second row and a second detector fiber of the second row.

16. The method of claim 9, wherein the sensor head includes a first row having a first source fiber and a second source fiber and a second row having a first detector fiber and a second detector fiber and the first source fiber is arranged nonsymmetrically with respect to the second source fiber, first detector fiber, and second detector fiber.

17. A method for characterizing an artery associated with flap tissue, the artery being arranged to provide blood to the flap tissue, the method comprising:

placing a sensor head of an optical imaging system in contact with the flap tissue at a first location, wherein the sensor head causes light to be reflected off of the flap tissue to identify a first oxygen saturation level and a second oxygen saturation level;

identifying the first oxygen saturation level associated with the flap tissue;

inhibiting a flow of blood through the artery;

identifying the second oxygen saturation level associated with the flap tissue after inhibiting the flow of blood through the artery;

determining whether the second oxygen saturation level is significantly different from the first oxygen saturation level; and

designating the artery as providing significant blood to the flap tissue if it is determined that the second oxygen saturation level is significantly different from the first oxygen saturation level,

the method further including designating the artery as providing insignificant blood to the flap tissue if it is determined that the second oxygen saturation level is not significantly different from the first oxygen saturation level, wherein designating the artery as providing insignificant blood to the flap tissue includes cutting the artery and tying off the artery.

18. A method for characterizing an artery associated with flap tissue, the artery being arranged to provide blood to the flap tissue, the method comprising:

placing a sensor head of an optical imaging system in contact with the flap tissue at a first location, wherein the sensor head causes light to be reflected off of the flap tissue to identify a first oxygen saturation level and a second oxygen saturation level;

identifying the first oxygen saturation level associated with the flap tissue;

inhibiting a flow of blood through the artery;

identifying the second oxygen saturation level associated with the flap tissue after inhibiting the flow of blood through the artery;

determining whether the second oxygen saturation level is significantly different from the first oxygen saturation level; and

designating the artery as providing significant blood to the flap tissue if it is determined that the second oxygen saturation level is significantly different from the first oxygen saturation level, wherein designating the artery as providing significant blood to the flap tissue includes cutting the artery and identifying the artery as a reattachment artery.

19. A method for identifying a location at which to obtain measurements of oxygen saturation levels, the method comprising:

positioning a sensor head at a first location in contact with a tissue, the sensor head being coupled to at least a first detector, a second detector, and a first source;

obtaining a first optical measurement, Us_1D1, and a second optical measurement, Us_1D2, using the sensor head, the first optical measurement being associated with the first detector when the first source emits light having a wavelength of λ

that is reflected into the first detector and the second optical measurement being associated with the second detector when the first source emits light having a wavelength of λ

that is reflected into the second detector;

determining whether at least a Q_λ

factor which is a first ratio of the first optical measurement to the second optical measurement is approximately equal to one; and

identifying the first location as the location at which to obtain the measurements of oxygen saturation levels if it is determined that the first ratio of the first optical measurement to the second optical measurement is approximately equal to one.

20. The method of claim 19 wherein if it is determined that the first ratio of the first optical measurement to the second optical measurement is not approximately equal to one, the method further includes:

determining whether the first ratio has a value that is closer to one than any other ratio of a plurality of ratios; and

identifying the first location as the location at which to obtain the measurements of oxygen saturation levels if it is determined that the first ratio has the value that is closer to one than any other ratio of the plurality of ratios.

21. The method of claim 19 further including:

measuring oxygen saturation levels at the first location if it is determined that the first ratio of the first optical measurement to the second optical measurement is approximately equal to one.

22. The method of claim 19 further comprising:

storing the first ratio of the first optical measurement to the second optical measurement and the first location in a memory to be compared with a plurality of ratios of other optical measurements from other locations.

23. The method of claim 19, wherein the optical imaging system comprises:

a probe comprising;

a connection interface, the connection interface being adapted to allow the probe to be coupled to a plurality of light sources and at least one photodetector, wherein the light sources and the photodetector are external to the probe; and

the sensor head comprising a first source fiber, a second source fiber, and a first detector fiber, the first source fiber and the second source fiber being arranged to be coupled to the plurality of light sources via the connection interface, and the first detector fiber being arranged to be coupled to the photodetector via the connection interface; and

a beam combiner, external to the probe, coupled to the first source fiber and the plurality of light sources via the connection interface.

24. The method of claim 19, wherein the sensor head includes a first row having a first source fiber and a second source fiber and a second row having a first detector fiber and a second detector fiber and the first source fiber is arranged nonsymmetrically with respect to the second source fiber, first detector fiber, and second detector fiber.

25. A method for assessing viability of a tissue structure, the method comprising:

placing a sensor head of an optical imaging system in contact with the tissue structure at a first location, wherein the sensor head causes light to be reflected off of the tissue structure to identify an oxygen saturation level;

obtaining the oxygen saturation level associated with the first location on the tissue structure;

determining whether the oxygen saturation level is within a predetermined range; and

identifying the first location as having an insufficient oxygen saturation level if it is determined that the oxygen saturation level is not within the predetermined range,

wherein the optical imaging system comprises;

a probe comprising;

a connection interface, the connection interface being adapted to allow the probe to be coupled to a plurality of light sources and at least one photodetector, wherein the light sources and the photodetector are external to the probe; and

the sensor head comprising a first source fiber, a second source fiber, and a first detector fiber, the first source fiber and the second source fiber being arranged to be coupled to the plurality of light sources via the connection interface, and the first detector fiber being arranged to be coupled to the photodetector via the connection interface; and

a beam combiner, external to the probe, coupled to the first source fiber and the plurality of light sources via the connection interface.

26. The method of claim 25 further including:

trimming the tissue structure at the first location if the first location is identified as having the insufficient oxygen saturation level.

27. The method of claim 25 wherein the tissue structure has an artery coupled thereto, the first location being located distally with respect to the artery.

28. The method of claim 25 wherein the tissue structure is a flap.

29. The method of claim 25, wherein the sensor head includes a first row of two source fibers and a second row of two detector fibers and wherein the first row of two source fibers is not in-line with the second row of two detector fibers.

30. The method of claim 29 wherein the first row is parallel to the second row.

31. The method of claim 30 wherein a first distance between a first source fiber of the first row and a second source fiber of the first row is the same as a second distance between a first detector fiber of the second row and a second detector fiber of the second row.

32. The method of claim 30 wherein a first distance between a first source fiber of the first row and a second source fiber of the first row is not the same as a second distance between a first detector fiber of the second row and a second detector fiber of the second row.

33. The method of claim 25, wherein the sensor head includes a first row having a first source fiber and a second source fiber and a second row having a first detector fiber and a second detector fiber and the first source fiber is arranged nonsymmetrically with respect to the second source fiber, first detector fiber, and second detector fiber.

34. A method for identifying a location at which to obtain measurements of oxygen saturation levels, the method comprising:

positioning a sensor head at a first location, the sensor head being coupled to at least a first detector, a second detector, a third detector, a fourth detector, a first source, and a second source;

sending light through the sensor head and detecting reflected light through tissue back into the sensor head;

obtaining a Q_λ

factor which is defined as