Method for Automated Opening of Craniotomies for Mammalian Brain Access

Patent metadata

Field	Value
Publication number	US-2016296242-A1
Application number	US-201615096256-A
Country	US
Kind code	A1
Filing date	Apr 11, 2016
Priority date	Apr 10, 2015
Publication date	Oct 13, 2016
Grant date	—

Abstract

A method for automated opening of craniotomies includes, under the control of a computer processor, drilling into a skull for a predetermined distance and determining when there is a conductance drop near the drilling tip that indicates skull breakthrough. If the conductance is not below a predetermined threshold, drilling continues iteratively manner until conductance is below the threshold. A craniotomy pattern may be predetermined and automatically drilled under control of the processor. A cranial window may be created by drilling along a path that interpolates between holes to form the circumference of the window. An automated craniotomy opening apparatus includes a drilling apparatus with a drilling tip, at least one drilling apparatus positioning device, a detection device, and a computer processor that controls the drilling apparatus, the positioning device, and the detection device according to the method. Determining conductance may include use of an impedance detection circuit.

First claim

What is claimed is:

1 . A method for automated opening of craniotomies, comprising:
positioning a craniotomy apparatus drilling tip at a starting position relative to a target skull; under the control of a computer processor specially configured with control software for operating a craniotomy apparatus,
drilling into the target skull with the drilling tip for a predetermined distance;
after drilling, determining the conductance near the drilling tip;
if the conductance is below a predetermined threshold, returning the drilling tip to a home position; and
if the conductance is not below the predetermined threshold, repeating the steps of drilling and determining until the conductance exceeds the predetermined threshold.

2 . The method of claim 1 , wherein the step of determining the conductance comprises the steps of:
under the control of the computer processor,
measuring impedance with an impedance detection circuit; and
calculating the conductance using the measured impedance.

3 . The method of claim 2 , wherein the step of measuring impedance comprises the steps of:
under the control of the computer processor,
sending a signal through the impedance circuit to the drilling tip;
detecting a voltage at the target skull; and
sending a signal representing the detected voltage from the impedance circuit to the computer processor.

4 . The method of claim 3 , wherein the step of calculating comprises determining a voltage drop across the impedance circuit.

5 . The method of claim 2 , wherein the step of measuring impedance comprises the steps of:
under the control of a computer processor,
sending a signal at a predetermined voltage through the impedance circuit to the target skull;
detecting a voltage at the drilling tip; and
sending a signal representing the detected voltage from the impedance circuit to the computer processor.

6 . The method of claim 5 , wherein the step of calculating comprises determining a voltage drop across the impedance circuit.

7 . The method of claim 1 , further comprising the steps of:
predetermining a drill hole pattern comprising a plurality of craniotomies to be drilled in the target skull using the method of claim 1 ; and creating the drill hole pattern by drilling the plurality of craniotomies using the method of claim 1 .

8 . The method of claim 7 , wherein the predetermined drill hole pattern is selected to facilitate creation of a cranial window in the target skull.

9 . The method of claim 8 , further comprising the step of creating the cranial window by drilling along a path that interpolates between the holes to form a circumference of the cranial window.

10 . An automated craniotomy opening apparatus, comprising:
a craniotomy drilling apparatus having a drilling tip; at least one craniotomy drilling apparatus positioning device connected to the craniotomy drilling apparatus; a detection device connected to the drilling tip; and a computer processor specially configured and connected to control the craniotomy drilling apparatus, the craniotomy drilling apparatus positioning device, and the detection device, the computer processor programmed to perform the steps of:
positioning the drilling tip with respect to the target skull at a predetermined position for drilling;
drilling into the target skull with the drilling tip for a predetermined distance;
after drilling, determining the conductance near the drilling tip using the detection device;
if the conductance is below a predetermined threshold, returning the drilling tip to a home position; and
if the conductance is not below the predetermined threshold, repeating the steps of drilling and determining until the conductance exceeds the predetermined threshold.

11 . The apparatus of claim 10 , wherein the detection device includes an impedance detection circuit.

12 . The apparatus of claim 11 , wherein the impedance detection circuit comprises:
a signal source; a sense resistor in series with the signal source; and an output for sending the detected impedance to the computer processor.

13 . The apparatus of claim 10 , wherein the detection device is attached to the drilling tip in a manner that permits measurements to be made while the drilling apparatus is running.

14 . The apparatus of claim 10 , wherein the drilling tip is a blunt-tipped end mill.

15 . The apparatus of claim 10 , wherein the craniotomy drilling apparatus positioning apparatus is a motorized stereotaxic stage connected to the drilling apparatus.

Assignees

• Massachusetts Inst Technology

Inventors

• Pak Nikita
• Kinney Justin P
• Boyden Edward S

Classifications

• A61B17/1695 Primary

  Trepans or craniotomes, i.e. specially adapted for drilling thin bones such as the skull · CPC title

• A61B34/32

  operating autonomously · CPC title

• A61B34/30

  Surgical robots · CPC title

• A61B90/10

  for stereotaxic surgery, e.g. frame-based stereotaxis · CPC title

• A61B2017/00026

  Conductivity or impedance, e.g. of tissue · CPC title