Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves 
  • A61B5/0507—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves  using microwaves or terahertz waves
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/06—Devices, other than using radiation, for detecting or locating foreign bodies ; determining position of probes within or on the body of the patient
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
  • A61B90/39—Markers, e.g. radio-opaque or breast lesions markers

Definitions

• the present invention relates to surgical swabs and methods for detecting surgical swabs and instruments during or following surgery.
• Medical swabs are generally made of absorbent, multi-layered cotton or cotton/lint-based material with a woven in PNC thread, coated in 55 % Barium Phosphate, which is detectable under X ray.
• EP 0 244 992 describes a process of manufacturing swabs to include a layer of X ray detectable material, allowing the detection of retained swabs under X ray control.
• Suture needles and instruments are most commonly made of high grade 622-625 surgical steel, and are magnetic.
• the present invention provides alternative detection systems suitable for routine practice or as a method for preventive retained item scanning and swabs suitable for use in such detection systems.
• a first aspect of the invention provides a method for detecting and/or locating within a body cavity (or otherwise during a surgical operation) a swab or surgical instrument (which may be a needle) which comprises a metal (material with high electrical conductivity) or magnetic material (or less preferably other detectable material), the method comprising the step of passing a detection sensor over the wound site, wherein the method does not involve the use of X-ray radiation.
• the detection sensor comprises a multi sensor array.
• a single sensor is considered sufficient to provide useful information.
• the multi sensor approach would allow individual sensors to be tuned at different frequencies (which may allow more detailed positional information to be obtained) and may allow wider beam spread. Multiple sensors may provide a more accurate location indication, which may be useful in larger cavities.
• the detection sensor is not intended to be inserted into the body.
• the method indicates the presence or possibly the number of marked swabs or other metallic items within the wound or cavity body cavity. It is preferred that the detection sensor is capable of detecting magnetic materials, for example surgical steel. The detection sensor may preferably generate and/or detect microwave radiation.
• the detection sensor may employ ultrasonic, radio/wireless proximity, thermal, luminescence, infrared, piezoelectric or fmoroscopy methods.
• the detection sensor has the following properties: 1. it is preferably in the form of a 'wand' which may be passed over the wound site
• It preferably has an audible and/or visible and/or vibrating warning system ie provides an audible or visible signal when a metallic or magnetic material is detected.
• the senor is preferably of a construction that will allow it to be fully sterilised (autoclaveable) or sheathed with a sterile covering (which may be purpose- designed for the sensor, and which may be disposable). 5. Alternatively or in addition the sensor may be fully disposable.
• Suitable detection sensors may be based on metal detector instruments used in law enforcement or security operations (for example in airport security), for example adapted to be sterilisable or to have a sterile covering, as discussed above. Such instruments will be well known to those skilled in the art.
• WO 01/51948 relates to a hand-mounted instrument and describes other instruments, for example in the form of wands. Such instruments may be particularly suitable for use in the present invention.
• US 5,936,586 and US 2002/0017904 also describe non-metal and metal detection instruments embodying principles which may be useful in instruments for use in the present invention.
• the senor comprises a (preferably battery operated and hand portable) wave guide (A) which includes a microwave oscillator for generating microwaves and (at least) two resonating slots on a wall of the wave-guide, and a microwave detector capable of detecting reflected microwaves.
• A preferably battery operated and hand portable wave guide
• Suitable detection sensors may also be based on Electronic Article Surveillance (EAS) systems used in retail environments. These have the advantage that they are designed to be substantially unaffected by the presence of steel or ferromagnetic objects such as the operating theatre bed structure.
• EAS Electronic Article Surveillance
• One embodiment of such a sensor system uses tags made of a soft magnetic material that is easily saturated.
• the detector contains a coil which generates a low (a few kHz) frequency alternating magnetic field.
• the tag magnetisation is a clipped waveform rich in harmonics which are detected by a receive coil in the detector.
• the tags can be in a number of forms, but typically can be a thin foil laminate either in a patch or in a thread about 1mm wide.
• the senor comprises a transmit coil and a receive coil, connected to a battery operated transmit and receive circuit capable of detecting harmonics in the magnetisation of the tag.
• a second (or further) detection sensor (which may also comprise a multi- sensor array) may be used. This may preferably be positioned on the opposite side of the patient to the first detection sensor. For example, the second detection sensor may be placed underneath the patient whilst the first detection sensor is used above (including to the side of) the patient.
• the second or further detection sensor may be oriented so that its multi- sensor array is rotated relative to the multi-sensor array of the first detection sensor.
• two or more detection sensors may be useful in creating a constant detection zone, for example by combining the signals received from the two or more detection sensors or multi-sensor arrays, as well known to those skilled in the art.
• a re-useable mat comprising a second multi- sensor array may be placed underneath the patient (Fig 2).
• the array may be similar to that in the first detection sensor but constructed to be 180 degrees out-of-phase. This arrangement may create a constant 'detection zone'.
• a still further aspect of the invention provides a detection sensor as defined above for use in medicine.
• a still further aspect of the invention provides a detection sensor as defined above for use in a method for detecting and/or locating within a body cavity (or otherwise during a surgical procedure) a swab or surgical instrument which comprises a metal or magnetic material (or other detectable material).
• a further aspect of the invention provides a detection sensor as defined above in the form of a mat.
• the invention provides a mat comprising a detection sense, preferably comprising a multi-sensor array.
• a further aspect of the invention provides a swab or surgical instrument which comprises a metal or magnetic material (or other detectable material) for use in a method for detecting and/or locating within a body cavity (or otherwise during a surgical procedure) the swab or surgical instrument, the method comprising the step of passing a detection sensor over the wound site, wherein the method does not involve the use of X-ray radiation.
• the detection sensor preferably comprises a multi sensor array, as discussed above.
• a further aspect of the invention provides a surgical swab comprising a magnetic material.
• the magnetic material does not comprise a noble metal, such as gold or silver as described in GB 805082.
• the magnetic material preferably comprises paramagnetic atoms or ions, for example comprises Fe, Co or Ni atoms or ions (which are ferromagnetic elements).
• the magnetic material may preferably comprise a ferromagnetic compound, for example a ferromagnetic compound listed in the CRC Handbook of Chemistry and Physics, 82 nd Edition 2001-2002 CRC Press LLC, Ed David R Lide. Magnetic materials are discussed extensively in the CRC Handbook (supra) and in references cited therein.
• the magnetic material is or comprises stainless steel, preferably surgical grade stainless steel, for example 622-625 stainless steel.
• the magnetic material or (in relation to the first aspect of the invention) metallic material or other detectable material may be incorporated in or round a thread embedded in the swab (which term includes any surgical dressing) structure.
• medical and surgical swabs generally have a PNC thread, coated in 55 % Barium Phosphate woven into the swab.
• the Barium Phosphate coating may be replaced by a metallic coating (Fig 1).
• This metallic coating (or other detectable material) allows detection via multi-sensor sensing devices including: a. Magnetic; b. Ultrasonic; c. Radio/wireless proximity; d.
• the thread may be woven into the gauze during manufacture of the swab or it may be sewn through the finished gauze or glued or otherwise attached thereto.
• the magnetic material may consist of a low-coercivity alloy such as AtalanteTM (Bekaert NDS n.v.Sputtered Films, Karreweg 18,B - 9870 Zulte, Belgium, with a coercivity typically less than 1 Oersted. This is available as a thin (less than 1 micron) layer sputtered onto a flexible polymer substrate.
• AtalanteTM Bekaert NDS n.v.Sputtered Films, Karreweg 18,B - 9870 Zulte, Belgium
• the magnetic material or metal is non-toxic, unaffected by sterilisation and by body fluids (or less preferably is coated or contained in such a material), incapable of causing abrasion or irritation, non-fraying and flexible. It is further desirable that it is easily obtainable and manipulable and is preferably cheap. In the case of steel needles and other foreign bodies, it may be necessary to coat the items with a thin layer of soft magnetic material if the harmonic magnetic field detection system is used.
• a further aspect of the invention provides a method for making a swab of the invention, comprising the step of incorporating a magnetic material into the swab.
• the magnetic material may be incorporated during formation of the material from which the swab is constructed, after formation of the material but before the swab is assembled, or after assembly of the structure of the swab.
• the magnetic material is incorporated on a thread on which the magnetic material is coated.
• a further aspect of the invention provides a swab of the invention for use in medicine.
• a still further aspect of the invention provides a swab of the invention for use in a method for detecting and/or locating within a body cavity the swab or surgical instrument, the method comprising the step of passing a detection sensor over the wound site, wherein the method does not involve the use of X-ray radiation.
• the detection sensor comprises a multi sensor array.
• Fig 2 If a foreign body (metal needle/instrument) or Swab manufactured with a flexible, metal coated PNC thread, is within Zone 'C it will create interference with one of the radiating slots and result in a signal being sent from the detecting diode resulting in an alarm signal (audio/visual). If no metallic or foreign bodies are within Zone 'C the balance of A and B is maintained causing no resultant alarm signal.
• Example 1 Patient monitoring during surgery.
• surgeon or an assistant scans the surgical zone prior to wound closer. This may be done in conjunction with existing swab and instrument checks.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Molecular Biology (AREA)
• Animal Behavior & Ethology (AREA)
• Biophysics (AREA)
• Pathology (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Medical Informatics (AREA)
• Veterinary Medicine (AREA)
• Surgery (AREA)
• Physics & Mathematics (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Human Computer Interaction (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Radiology & Medical Imaging (AREA)
• Magnetic Resonance Imaging Apparatus (AREA)
• Geophysics And Detection Of Objects (AREA)

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• 2002
  • 2002-03-06 GB GBGB0205188.6A patent/GB0205188D0/en not_active Ceased
• 2003
  • 2003-03-06 WO PCT/GB2003/000945 patent/WO2003073934A1/en not_active Application Discontinuation
  • 2003-03-06 AU AU2003209466A patent/AU2003209466A1/en not_active Abandoned
  • 2003-03-06 EP EP03743439A patent/EP1538982A1/de not_active Withdrawn

Non-Patent Citations (1)

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