System for controlling a motor driven surgical cutting instrument

• US 6,358,263 B2
• Filed: 02/20/2001
• Issued: 03/19/2002
• Est. Priority Date: 10/20/1998
• Status: Expired due to Term

• Current Assignee: Suros Surgical Systems Incorporated (Hologic Incorporated)
• Original Assignee: Promex SA (Uzinsider SA)
• Inventors: Kara, Miklos T., McCary, Brian, Henry, Daniel John, Miller, Michael E., Mark, Joseph L.
• Primary Examiner(s): Truong, Kevin
• Application Number:
  US09/789,040
• Publication Number:
  US 20010007944A1
• Time in Patent Office: 392 Days
• Field of Search: 606/167, 606/170, 606/171, 606/174, 606/180, 604/22
• US Class Current: 606/167
• CPC Class Codes: A61B 17/32002 with continuously rotating, oscillating or reciprocating cutting instruments
• CPC Class Codes: A61B 2017/00017 Electrical control of surgical instruments
• CPC Class Codes: A61B 2017/00039 Electric or electromagnetic phenomena other than conductivity, e.g. capacity, inductivity, Hall effect

Abstract

A system is provided for controlling the stopping position of a surgical cutting tool relative to a tissue entrance location of a cannula housing the cutting tool. A signal processor is responsive to a motor activation signal to provide a motor activation signal to a motor control unit for driving a motor, which activates the cutting tool positioned in a cannula. The signal processor is responsive to a motor stop signal and to a stop position signal to stop the cutting tool relative to the tissue entrance location of the cannula to thereby avoid trapping a portion of the tissue base between the cutting tool and a boundary of the cannula opening.

Claims

1. A method for controlling a brushed DC motor in a tissue cutting apparatus having a cutting member, comprising the steps of:

operating the brushed DC motor at a cutting speed effective to excise tissue with the tissue cutting apparatus;

sensing a stop signal indicative of a command to stop the tissue cutting apparatus;

thereafter sensing a first passage of the cutting member by a fixed location relative to the cutting member; and

thereafter de-energizing the brushed DC motor when the cutting member is at the fixed location so that movement of the motor stops with the cutting member substantially at a predetermined position relative to the fixed location.

2. The method according to claim 1, wherein:

the step of operating the brushed DC motor includes controlling the speed of the motor using a current feedback loop; and

further comprising the step of disconnecting the current feedback loop after sensing the stop signal.

3. The method according to claim 1 further comprising:

after sensing the first passage of the cutting member, reducing the speed of the motor to a reduced speed effective to overcome the rotational resistance of the brushed DC motor but substantially less than said cutting speed.

4. The method according to claim 3, wherein the step of de-energizing the motor occurs after sensing a second passage of the cutting member by the fixed location.

5. The method according to claim 1, wherein the steps of sensing the passage of the cutting member includes:

providing a marker at a predetermined position on the cutting member; and

providing a sensor at the fixed location on the cutting apparatus, the sensor operable to generate a signal when the marker passes by the sensor.

6. A method for controlling a brushed DC motor in a tissue cutting apparatus having a cutting member, comprising the steps of:

operating the brushed DC motor at a cutting speed effective to excise tissue with the tissue cutting apparatus;

sensing a stop signal indicative of a command to stop the tissue cutting apparatus;

sensing a first passage of the cutting member by a fixed location relative to the cutting member;

sensing a second passage of the cutting member by the fixed location; and

stopping the brushed DC motor substantially immediately upon sensing the second passage to stop the cutting member at a predetermined position.