SURGICAL RESECTION APPARATUS

• US 20100286686A1
• Filed: 09/24/2008
• Published: 11/11/2010
• Est. Priority Date: 09/25/2007
• Status: Active Grant

• Current Assignee: Creo Medical Ltd.
• Original Assignee: Creo Medical Ltd.
• Inventors: Hancock, Christopher Paul
• Granted Patent: US 8,795,267 B2
• Time in Patent Office: Days
• US Class Current: 606/33
• CPC Class Codes: A61B 17/3211 Surgical scalpels, knives; Accessories therefor
• CPC Class Codes: A61B 18/18 by applying electromagnetic radiation, e.g. microwaves radiation therapy A61N5/00
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 2018/00642 with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/00648 using more than one sensed parameter
• CPC Class Codes: A61B 2018/00708 switching the power on or off
• CPC Class Codes: A61B 2018/00732 Frequency
• CPC Class Codes: A61B 2018/00755 Resistance or impedance
• CPC Class Codes: A61B 2018/00785 Reflected power
• CPC Class Codes: A61B 2018/1823 Generators therefor
• CPC Class Codes: A61B 2018/183 characterised by the type of antenna
• CPC Class Codes: A61B 2018/1876 with multiple frequencies

Abstract

Surgical cutting apparatus having a treatment channel and a measurement channel for conveying microwave energy from a source to an antenna at a cutting edge. The measurement channel operates at lower power than the treatment channel for determining when higher energy can be safely applied. The apparatus may deliver microwave radiation at differing frequencies to one or more antennas at the cutting edge, e.g. to provide different treatment effects. The source may generate an output for an antenna whose frequency can be selected e.g. for most efficient operation. Selection may be automatic based on detected magnitude and phase of reflected signals during a frequency sweep of a forward signal. Power delivered to tissue via the cutting element may be manually boosted to deal with large blood vessels. The apparatus may include a reflected power monitor for recognising behaviour in reflected signals received from the antenna to trigger automatic pre-emptive action.

Claims

1-42. -42. (canceled)

43. Surgical cutting apparatus having:

a microwave radiation source arranged to generate a microwave radiation signal;

a surgical instrument having a cutting element with an edge for cutting biological tissue and an antenna connected to the microwave radiation source and arranged to emit a substantially uniform microwave radiation field at the edge of the cutting element;

a reflected radiation detector connected between the microwave radiation source and the antenna to detect signals reflected back from the antenna;

a reflected power monitor arranged to detect a signature event in the reflected signals detected by the reflected radiation detector; and

a power level adjuster connected between the microwave radiation source and antenna and arranged to automatically adjust a power level of the microwave radiation signal received by the antenna if the monitor detects a signature event.

44. Apparatus according to claim 43, wherein the signature event is either:

(i) a predetermined rate of change of reflected power or a constant level of reflected power detected during a certain time slot or for a certain duration;

or

(ii) a certain change in the impedance of the tissue derived from changes in the behaviour of the reflected power.

45. Apparatus according to claim 43, wherein the monitor includes a differentiator arranged to:

measure a value of dv/dt (change of voltage with time) for the reflected signals, and

compare the measured value to a threshold value, whereby the signature event is a value of dv/dt that is higher than a threshold.

46. Apparatus according to claim 43, wherein the power level adjustor is arranged to:

reduce the power level as soon as the signature event is detected, and

ramp the power level back up in a recovery time period after the reduction in power level.

49. Apparatus according to claim 43, wherein the antenna is selectively connectable to the microwave radiation source via a first channel for conveying a microwave radiation signal at a first power level for treatment and a second channel for conveying a microwave radiation signal at a second power level for measurement, and

wherein the antenna is connected to the detector via a signal transfer unit which is arranged to route signals reflected from the antenna along the second channel directly to the detector.

50. Apparatus according to claim 49 having a switch arranged to selectively connect the antenna to either the first channel or the second channel, the switch comprising a filtering arrangement having two selectable configurations.

51. Apparatus according to claim 43, wherein:

the microwave radiation source is arranged to generate a first microwave radiation signal having a first frequency and a second microwave radiation signal having a second frequency; and

the surgical instrument comprises;

a first antenna connectable to the microwave radiation source to receive the first microwave radiation signal and arranged to emit a substantially uniform microwave radiation field at the first frequency along the edge of the cutting element, and

a second antenna connectable to the microwave radiation source to receive the second microwave radiation signal and arranged to emit from the surgical instrument a microwave radiation field at the second frequency,

wherein the second frequency is lower than the first frequency.

52. Apparatus according to claim 51, wherein the first and second antennas comprise a single antenna structure operable over a band or frequencies including the first and second frequencies or arranged to resonate at the first and second frequencies.

53. Apparatus according to claim 52, wherein the antenna structure comprises a waveguide and the first and second microwave radiation signals correspond to different propagation modes in the waveguide.

54. Apparatus according to claim 43, wherein the microwave radiation signal generated by the microwave radiation source has an adjustable frequency.

55. Apparatus according to claim 54, wherein the microwave radiation source is a wideband frequency oscillator able to emit a microwave radiation signal over a range of frequencies, and wherein the output frequency is selectable to set up a resonant condition when the antenna is in contact with the tissue or to correspond to a frequency where an energy absorption peak occurs in the biological tissue being treated.

56. Apparatus according to claim 54, wherein the microwave radiation source comprises a variable frequency signal generator arranged to output a first signal having a stable frequency within a range of frequencies and an amplification unit arranged to amplify the first signal into a second signal having a power level suitable for treatment, and wherein the amplification unit is capable of amplifying a signal having any frequency in the range of frequencies to a power lever of 10 W or more.

57. Apparatus according to claim 54 including a reflected radiation detector arranged to receive signals reflected back from the antenna, wherein the detector is arranged to detect the magnitude and phase of the reflected signal whereby the adjustable output frequency is controllable based on the detected magnitude and phase.

58. Apparatus according to claim 57, wherein the microwave radiation source is arranged to sweep the output frequency of a forward microwave radiation signal across a range of frequencies, whereby a suitable frequency for treatment is selectable from the range of frequencies based on the detected magnitude and phase of reflected signals corresponding to the swept forward signal.

47. Surgical cutting apparatus having:

a microwave radiation source arranged to generate a microwave radiation signal;

a surgical instrument having a cutting element with an edge for cutting biological tissue and an antenna connected to the microwave radiation source and arranged to emit a substantially uniform microwave radiation field at the edge of the cutting element;

a reflected radiation detector connected between the microwave radiation source and the antenna to detect signals reflected back from the antenna; and

a reflected power monitor arranged to detect a signature event in the reflected signals detected by the reflected radiation detector,

wherein the monitor is arranged to emit an audible or visual signal when a signature event is detected.

48. Apparatus according to claim 47, wherein the audible or visual signal is representative of the detected event to provide information enabling optimal movement of the cutting element.

59. A surgical instrument having:

a cutting element with an edge for cutting biological tissue;

a first antenna arranged to emit a substantially uniform microwave field of radiation at a first frequency at the edge of the cutting element; and

a second antenna arranged to emit a microwave radiation field at a second frequency from the cutting element, the second frequency being lower than the first frequency.

60. A surgical instrument according to claim 59, wherein the cutting element comprises a ceramic body having a coupling portion for attaching to a waveguide and a blade portion which includes the edge for cutting biological tissue, wherein the first antenna has a radiating portion integral with the blade portion and the coupling portion includes an impedance transformer.