WO1995024866A1 - Target for laser powered surgical instrument - Google Patents

Target for laser powered surgical instrument Download PDF

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Publication number
WO1995024866A1
WO1995024866A1 PCT/US1995/003305 US9503305W WO9524866A1 WO 1995024866 A1 WO1995024866 A1 WO 1995024866A1 US 9503305 W US9503305 W US 9503305W WO 9524866 A1 WO9524866 A1 WO 9524866A1
Authority
WO
WIPO (PCT)
Prior art keywords
target
laser
surgical instrument
shockwaves
plasma
Prior art date
Application number
PCT/US1995/003305
Other languages
French (fr)
Inventor
Jack M. Dodick
Original Assignee
Dodick Jack M
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dodick Jack M filed Critical Dodick Jack M
Publication of WO1995024866A1 publication Critical patent/WO1995024866A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • 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
    • A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
    • A61F9/007—Methods or devices for eye surgery
    • A61F9/008—Methods or devices for eye surgery using laser
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/18—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves
    • A61B18/20—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser
    • A61B18/22—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor
    • A61B18/26—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor for producing a shock wave, e.g. laser lithotripsy
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/18—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves
    • A61B18/20—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser
    • A61B18/22—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor
    • A61B18/26—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor for producing a shock wave, e.g. laser lithotripsy
    • A61B2018/266—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor for producing a shock wave, e.g. laser lithotripsy the conversion of laser energy into mechanical shockwaves taking place in a part of the probe
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • 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
    • A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
    • A61F9/007—Methods or devices for eye surgery
    • A61F9/008—Methods or devices for eye surgery using laser
    • A61F2009/00885—Methods or devices for eye surgery using laser for treating a particular disease
    • A61F2009/00887—Cataract

Definitions

  • This invention relates to an improvement in a laser powered surgical instrument and more particularly to the nature of the target that generates plasma upon receipt of input laser pulses and which plasma creates Shockwaves used to fracture tissue positioned or held at an opening near the distal end of the surgical instrument.
  • This invention relates to the optimum materials to be employed as the target in the instrument described in said application Serial No. 07/844,661. Accordingly, reference is made to patent application Serial No. 07/844,661 for discussion of the prior art and for a detailed discussion of the structure of the instrument for which this invention is an improvement.
  • the target for the laser generates plasma in response to each laser pulse and thus the target gradually wears away.
  • One application of the instrument is to the removal of a cataract. Ten thousand pulses may be required during each operation. It is essential that a target withstand the large number of pulses required for an operation so that there is target material present in the path of the laser pulses at the end of the operation. The target can be replaced for a new operation or a new instrument can be used.
  • the target material can be made thicker so that it will withstand a number of pulses. But that tends to increase the size, weight and cost of the instrument.
  • the object of this invention is to provide optimum target materials for use in a laser surgical instrument.
  • the metals titanium and zirconium and alloys thereof provide the right combination of characteristics to be useful and useable as a laser target in a small diameter laser powered surgical instrument.
  • FIG. 1 is a longitudinal sectional view of the distal end of the needle like probe of this invention.
  • FIG. 2 is a block diagram illustrating the use of a pulsed laser generator to provide the input energy to the fiber optic element of the surgical instrument.
  • the probe 10 has a tubular outside wall 12 with an outer diameter of 2 millimeters (2 mm) and a wall thickness of approximately 0.2 mm. Within the wall 12 there is an inner tubular wall 14 that also has a wall thickness of about 0.2 mm. Passageway 16 permits infusion of saline through the wall opening 18 into the operating area.
  • the passageway 20 is an aspirating passageway. Fractured tissue and fluid are drawn in through the front port 22 and aspirated at the passageway 20.
  • the walls 12 and 14 are made of stainless steel.
  • An insert 24 is held at the distal end of the wall 12. This insert may be made of either titanium or zirconium or an alloy of those two elements.
  • An optical fiber 26 extends through the passageway 16 and has its distal end held in position by an opening in the proximal wall portion 25 of the insert 24.
  • Pulses of laser energy are delivered through the optical fiber 26 and impinge on the inner surface 27 of the forward wall portion 29 of the insert 24. As these pulses impinge on the surface 27, they react with the material of the insert 24 to form plasma which then generates Shockwaves that travel down through the liquid medium, which is usually saline, that fills the chamber 30 at the distal end of the instrument 10. These Shockwaves are delivered to the tissue receiving opening 22 where they fracture tissue that is positioned or held there.
  • the surface 27 of the titanium or zirconium target 24 gradually deteriorates in response to each pulse of the target. A target might withstand 10,000 pulses. Eight thousand pulses are often required for a single operation.
  • a known and standard laser used with this equipment is a Neodymium-YAG pulsed Q switched laser 30 providing laser energy with a wavelength of 1,064 nano ⁇ meters.
  • the laser energy is provided in pulses having a duration of eight nano-seconds and a pulse repetition rate of 20 pulses per second.
  • the energy provided is 100 milli- joules per second.
  • the energy of each pulse is about five milli-joules.
  • Such an arrangement functions to remove a cataract in eye surgery.
  • a target made of titanium or zirconium will operate well with such a laser pulse system.
  • the target be made of material which is not toxic to the human body.
  • the plasma formed from the optical breakdown of the surface of the target frees molecules of the material in such a fashion that it is prudent that the material be non-toxic.
  • inert metals which can be used without creating a toxicity problem, most of those have a melting point sufficiently high that they would not generate plasma with pulses of the type described above. Accordingly, such a target would not degrade. But it would not perform the function required.
  • the heat conductivity of the target metal and the absorption of laser energy by the target metal affect the ability of the target to function properly.
  • the target metal conducts heat readily (that is has high heat conductivity) or absorbs the laser energy readily, higher energy laser pulses are needed to generate the required plasma.
  • the metal have relatively low heat conductivity and a relatively low absorption co-efficient for the Neodymium- YAG laser wavelengths. It is believed that these two parameters of low heat conduction and low laser energy absorption aid in concentrating the incident energy at the surface and thus bring the energy level to the point where plasma and the consequent Shockwaves are generated.

Landscapes

  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Surgery (AREA)
  • Optics & Photonics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Public Health (AREA)
  • General Health & Medical Sciences (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Ophthalmology & Optometry (AREA)
  • Veterinary Medicine (AREA)
  • Animal Behavior & Ethology (AREA)
  • Molecular Biology (AREA)
  • Electromagnetism (AREA)
  • Otolaryngology (AREA)
  • Medical Informatics (AREA)
  • Vascular Medicine (AREA)
  • Laser Surgery Devices (AREA)
  • Lasers (AREA)

Abstract

A small diameter laser powered surgical instrument usable in ophthalmology employs laser pulses which impinge on a target material made of titanium or zirconium or alloys thereof. These target materials create a plasma when subjected to the laser pulses. This plasma creates shockwaves that are transmitted through a saline media within a chamber at the distal end of the instrument to a port where the shockwaves impinge upon tissue held at the port. The shockwaves fracture tissue which is then aspirated out of an aspirating passageway.

Description

TARGET FOR LASER POWERED SURGICAL INSTRUMENT
Reference To Related Applications
This application is a continuation-in-part of co- pending patent applications filed by applicant in the United States Patent Office as Serial. No. 07/844,661 on April 8, 1992 as a National Phase of a PCT case which in turn is a continuation-in-part of Serial No. 07/426,971 filed on October 25, 1989 entitled: Laser Powered Surgical Instrument and Serial No. 07/429,121 filed on October 30, 1989 entitled: Surgical Instrument With Input Power Collector.
Background Of The Invention This invention relates to an improvement in a laser powered surgical instrument and more particularly to the nature of the target that generates plasma upon receipt of input laser pulses and which plasma creates Shockwaves used to fracture tissue positioned or held at an opening near the distal end of the surgical instrument.
This invention relates to the optimum materials to be employed as the target in the instrument described in said application Serial No. 07/844,661. Accordingly, reference is made to patent application Serial No. 07/844,661 for discussion of the prior art and for a detailed discussion of the structure of the instrument for which this invention is an improvement. The target for the laser generates plasma in response to each laser pulse and thus the target gradually wears away. One application of the instrument is to the removal of a cataract. Ten thousand pulses may be required during each operation. It is essential that a target withstand the large number of pulses required for an operation so that there is target material present in the path of the laser pulses at the end of the operation. The target can be replaced for a new operation or a new instrument can be used. It is important that the target responds to the input pulse by generating plasma, so that the resultant Shockwave will be created. If the target did not degrade by generating plasma, the function of the invention would not occur. The target material can be made thicker so that it will withstand a number of pulses. But that tends to increase the size, weight and cost of the instrument.
Accordingly, the object of this invention is to provide optimum target materials for use in a laser surgical instrument.
Brief Description
In brief, it has been found that the metals titanium and zirconium and alloys thereof provide the right combination of characteristics to be useful and useable as a laser target in a small diameter laser powered surgical instrument.
Brief Description Of The Drawings
FIG. 1 is a longitudinal sectional view of the distal end of the needle like probe of this invention. FIG. 2 is a block diagram illustrating the use of a pulsed laser generator to provide the input energy to the fiber optic element of the surgical instrument.
/24866
4 Description Of The Preferred Embodiments
Because the device of this invention is described in detail in the. referenced patent application Serial No. 07/844,661, the structure and operation of this instrument will not be discussed in great detail herein.
The probe 10 has a tubular outside wall 12 with an outer diameter of 2 millimeters (2 mm) and a wall thickness of approximately 0.2 mm. Within the wall 12 there is an inner tubular wall 14 that also has a wall thickness of about 0.2 mm. Passageway 16 permits infusion of saline through the wall opening 18 into the operating area. The passageway 20 is an aspirating passageway. Fractured tissue and fluid are drawn in through the front port 22 and aspirated at the passageway 20. The walls 12 and 14 are made of stainless steel.
An insert 24 is held at the distal end of the wall 12. This insert may be made of either titanium or zirconium or an alloy of those two elements. An optical fiber 26 extends through the passageway 16 and has its distal end held in position by an opening in the proximal wall portion 25 of the insert 24.
Pulses of laser energy are delivered through the optical fiber 26 and impinge on the inner surface 27 of the forward wall portion 29 of the insert 24. As these pulses impinge on the surface 27, they react with the material of the insert 24 to form plasma which then generates Shockwaves that travel down through the liquid medium, which is usually saline, that fills the chamber 30 at the distal end of the instrument 10. These Shockwaves are delivered to the tissue receiving opening 22 where they fracture tissue that is positioned or held there. The surface 27 of the titanium or zirconium target 24 gradually deteriorates in response to each pulse of the target. A target might withstand 10,000 pulses. Eight thousand pulses are often required for a single operation. A known and standard laser used with this equipment is a Neodymium-YAG pulsed Q switched laser 30 providing laser energy with a wavelength of 1,064 nano¬ meters. The laser energy is provided in pulses having a duration of eight nano-seconds and a pulse repetition rate of 20 pulses per second. The energy provided is 100 milli- joules per second. The energy of each pulse is about five milli-joules. Such an arrangement functions to remove a cataract in eye surgery.
A target made of titanium or zirconium will operate well with such a laser pulse system.
It is important that the target be made of material which is not toxic to the human body. The plasma formed from the optical breakdown of the surface of the target frees molecules of the material in such a fashion that it is prudent that the material be non-toxic.
Although there are a number of inert metals which can be used without creating a toxicity problem, most of those have a melting point sufficiently high that they would not generate plasma with pulses of the type described above. Accordingly, such a target would not degrade. But it would not perform the function required.
It is believed that the heat conductivity of the target metal and the absorption of laser energy by the target metal affect the ability of the target to function properly. In particular, if the target metal conducts heat readily (that is has high heat conductivity) or absorbs the laser energy readily, higher energy laser pulses are needed to generate the required plasma. Thus it is important that the metal have relatively low heat conductivity and a relatively low absorption co-efficient for the Neodymium- YAG laser wavelengths. It is believed that these two parameters of low heat conduction and low laser energy absorption aid in concentrating the incident energy at the surface and thus bring the energy level to the point where plasma and the consequent Shockwaves are generated.

Claims

What Is Claimed Is:
1. In a surgical instrument for fracturing tissue having a tubular needle with a distal end and means for delivering laser energy to the distal end of said needle, the improvement comprising: a target adjacent to said laser delivery means at said distal end of said tubular needle, said target having a surface positioned to receive energy from said laser energy delivering means for forming plasma in response to receipt of said laser energy, said target being composed of materials consisting substantially of titanium, zirconium and alloys of titanium and zirconium.
PCT/US1995/003305 1994-03-15 1995-03-15 Target for laser powered surgical instrument WO1995024866A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US21366394A 1994-03-15 1994-03-15
US08/213,663 1994-03-15

Publications (1)

Publication Number Publication Date
WO1995024866A1 true WO1995024866A1 (en) 1995-09-21

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ID=22795996

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1995/003305 WO1995024866A1 (en) 1994-03-15 1995-03-15 Target for laser powered surgical instrument

Country Status (1)

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WO (1) WO1995024866A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990009762A1 (en) * 1989-02-22 1990-09-07 Physical Sciences Inc. Acoustic impact delivery catheter with end cap
WO1991006271A1 (en) * 1989-10-25 1991-05-16 Jack Murray Dodick Surgical instrument with input power transducer

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990009762A1 (en) * 1989-02-22 1990-09-07 Physical Sciences Inc. Acoustic impact delivery catheter with end cap
WO1991006271A1 (en) * 1989-10-25 1991-05-16 Jack Murray Dodick Surgical instrument with input power transducer

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