Vitrectomy probe with magnetically driven cutter
A vitrectomy probe includes a probe body and a needle portion projecting from the probe body. The needle portion includes a tube which extends at least partially in the needle portion and at least partially in the probe body. A cutter is positioned inside the tube in the needle portion. The cutter is at least partially composed of a permanently magnetic material. A field-creation unit is adapted to create an induced magnetic field, with the cutter being movable between a first position and a second position based in part on the induced magnetic field. The tube may be at least partially composed of a temporarily magnetic material. In one embodiment, the field-creation unit includes a driving magnet positioned in the probe body and adapted to selectively magnetize the tube.
1 . A vitrectomy probe comprising:
a probe body and a needle portion projecting from the probe body;
the needle portion including a tube extending at least partially in the probe body, the tube is at least partially composed of a temporarily magnetic material;
a cutter positioned inside the tube, the cutter being movable relative to the tube, the cutter being at least partially composed of a permanently magnetic material; and
a field-creation unit adapted to create an induced magnetic field, the cutter being movable between a first position and a second position based in part on the induced magnetic field, the field-creation unit includes an electromagnet positioned in the probe body and coiled around the tube; and
wherein a flow of electric current in the electromagnet selectively magnetizes the tube, the magnetized tube inducing movement in the cutter.
2 . The vitrectomy probe of claim 1 , further comprising:
a spring operatively connected to the cutter and adapted to bias the cutter in the first position.
3 . The vitrectomy probe of claim 1 , wherein the tube includes a first port adapted to receive aspirated tissue and the cutter includes a second port at least partially coextensive with the first port.
4 . The vitrectomy probe of claim 1 , wherein a respective length of the needle portion is about three to six times greater than the respective length of the cutter.
5 . The vitrectomy probe of claim 1 , wherein a respective length of the needle portion is at least five times greater than the respective length of the cutter.
6 . The vitrectomy probe of claim 1 , wherein:
the field-creation unit includes a wire positioned around the tube in sufficient proximity to the cutter such that flow of an electric current through the wire induces movement of the cutter.
7 . The vitrectomy probe of claim 6 , further comprising:
a controller adapted to adjust a polarity of the electric current to alter a direction of the movement of the cutter, the controller having a processor and a non- transitory, tangible memory on which instructions are recorded.
8 . A vitrectomy probe comprising:
a probe body and a needle portion projecting from the probe body;
the needle portion including a tube extending at least partially in the probe body, the tube being at least partially composed of a temporarily magnetic material;
a cutter positioned inside the tube, the cutter being movable relative to the tube, the cutter being at least partially composed of a permanently magnetic material; and
a field-creation unit including an electromagnet positioned in the probe body and coiled around the tube; and
wherein a flow of electric current in the electromagnet selectively magnetizes the tube, the magnetized tube inducing movement in the cutter.
9 . The vitrectomy probe of claim 8 , wherein a respective length of the needle portion is about three to six times greater than the respective length of the cutter.
10 . The vitrectomy probe of claim 8 , further comprising:
a controller adapted to adjust a polarity of the electric current to alter a direction of the movement of the cutter, the controller having a processor and a non-transitory, tangible memory on which instructions are recorded.
11 . The vitrectomy probe of claim 8 , wherein the tube includes a first port adapted to receive aspirated tissue and the cutter includes a second port at least partially coextensive with the first port.