Electrosurgical instrument
An improved electrosurgical instrument, specifically a scissor style vessel sealer, comprising two overmoulded jaws formed from a structural polymer held in place by a pivot pin. The moulded structural polymer replaces many metal components which would otherwise be required for such an assembly. Not only does the use of the moulded structural polymer simplify the assembly of the instrument, it also enables the following additional functionality: moulded pivot holes, flanges providing lateral support, and a flexible lever arm which is designed to provide the force needed to clamp and seal vessels.
1 . An electrosurgical instrument, comprising:
a first component comprising a distal first jaw member, a first central section and a proximal first arm, the first component being formed from a first single piece of polymer material;
a second component comprising a distal second jaw member and a second central section, the second component being formed from a second single piece of polymer material, wherein:
the second central section is connected to a proximal second arm;
the first and second components are pivotably connected such that at least one of the proximal first and second arms is movable with respect to the other of the proximal first and second arms between an open position in which the proximal first and second arms are spaced one from another and a closed position in which the proximal first and second arms are brought closer together, the distal first and second jaw members being moveable between first and second conditions in response to relative movement of the at least one of the proximal first and second arms; and
at least the proximal first arm is formed of a shape and thickness of the polymer material such that it flexes past a certain application force, the polymer material having a flexural strength of at least 200 MPa and a cross-sectional area of 30-50 mm 2 , a cross-section of the first arm being taken perpendicular relative to a length of the first arm, whereby in use the distal first and second jaw members provide a clamping force to clamp a vessel held between the distal first and second jaw members, the flexing of the proximal first arm past the certain application force preventing excess clamping force being applied to the vessel.
2 . An electrosurgical instrument according to claim 1 , wherein a flexibility of the proximal first arm is selected such that the clamping force is within a predetermined range.
3 . An electrosurgical instrument according to claim 1 , wherein:
at least one of the distal first and second jaw members comprises an electrically conductive sealing surface for communicating RF energy through tissue held therebetween;
at least one of the proximal first and second arms comprises radio RF electrical connections capable of connecting the electrically conductive sealing surface to a source of RF energy.
4 . An electrosurgical instrument according to claim 1 , wherein at least one of the proximal first arm and the proximal second arm comprises a finger loop.
5 . An electrosurgical instrument according to claim 1 , wherein the first and second components are slotted together such that the second component slots through an opening in the first central section of the first component.
6 . An electrosurgical instrument according to claim 5 , wherein:
an opening of the first central section of the first component is defined by first and second flanges, and the second central section of the second component is held in the opening of the first central section of the first component, the second central section of the second component being supported by the first and second flanges.
7 . An electrosurgical instrument according to claim 6 , wherein the first and second components are pivotably connected using a pivot pin.
8 . An electrosurgical instrument according to claim 7 , wherein:
the pivot pin threads through a first pivot hole in the first flange;
a second pivot hole in the second central section of the second component; and
a third pivot hole in the second flange.
9 . An electrosurgical instrument according to claim 1 , wherein the first and second components are pivotably connected using a pivot pin.
10 . An electrosurgical instrument according to claim 1 , further comprising an activation button operable to deliver a source of radio frequency (RF) energy to at least one of the distal first and second jaw members.
11 . An electrosurgical instrument according to claim 1 , wherein the distal first and second jaw members comprise a pair of bipolar forceps.
12 . An electrosurgical instrument according to claim 1 , wherein:
the first single piece of polymer material and
the second single piece of polymer material are formed from a structural polymer overmould having at least 50% glass fiber therein.
13 . An electrosurgical system, comprising:
an RF electrosurgical generator; and
an electrosurgical instrument, comprising:
a first component comprising a distal first jaw member, a first central section and a proximal first arm, the first component being formed from a first single piece of polymer material;
a second component comprising a distal second jaw member and a second central section, the second component being formed from a second single piece of polymer material, wherein:
the second central section is connected to a proximal second arm;
the first and second components are pivotably connected such that at least one of the proximal first and second arms is movable with respect to the other arm between an open position in which the proximal first and second arms are spaced one from another and a closed position in which the proximal first and second arms are brought closer together, the distal first and second jaw members being moveable between first and second conditions in response to relative movement of at least one of the proximal first and second arms; and
at least the proximal first arm is formed of a shape and thickness of the polymer material such that it flexes past a certain application force, the polymer material having a flexural strength of at least 200 MPa and a cross-sectional area of 30-50 mm 2 , a cross-section of the first arm being taken perpendicular relative to a length of the first arm, whereby in use the distal first and second jaw members provide a clamping force to clamp a vessel held between the first and second jaw members, the flexing of an at least first arm past the certain application force preventing excess clamping force being applied to the vessel.