0
Technical Briefs

Automating Skeletal Expansion: An Implant for Distraction Osteogenesis of the Mandible

[+] Author and Article Information
John C. Magill1

 Physical Sciences Inc., 20 New England Business Center, Andover, MA 01810magill@psicorp.com

Marten F. Byl

 Physical Sciences Inc., 20 New England Business Center, Andover, MA 01810byl@psicorp.com

Batya Goldwaser

Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Harvard School of Dental Medicine, 55 Fruit Street, Boston, MA 02114bgoldwaser@partners.org

Maria Papadaki

Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Harvard School of Dental Medicine, 55 Fruit Street, Boston, MA 02114mpapadaki@partners.org

Roger Kromann

 Embedded Systems Design, Inc., 85 5th St. NW, Suite D, PMB 208, Atlanta, GA 30308rkromann@esdnet.com

Brent Yates

 Embedded Systems Design, Inc., 85 5th St. NW, Suite D, PMB 208, Atlanta, GA 30308byates@esdnet.com

Joseph R. Morency

 Physical Sciences Inc., 20 New England Business Center, Andover, MA 01810morency@psicorp.com

Leonard B. Kaban

Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Harvard School of Dental Medicine, 55 Fruit Street, Boston, MA 02114lkaban@partners.org

Maria J. Troulis

Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Harvard School of Dental Medicine, 55 Fruit Street, Boston, MA 02114mtroulis@partners.org

1

Corresponding author.

J. Med. Devices 3(1), 014502 (Mar 09, 2009) (7 pages) doi:10.1115/1.3071969 History: Received October 30, 2007; Revised December 05, 2008; Published March 09, 2009

Distraction osteogenesis is a technique of bone lengthening that makes use of the body’s natural healing capacity. An osteotomy is created, and a rigid distraction device is attached to the bone. After a latency period, the device is activated two to four times per day for a total of 1 mm/day of bone lengthening. This technique is used to correct a variety of congenital and acquired deformities of the mandible, midface, and long bones. To shorten the treatment period and to eliminate the complications of patient activation of the device, an automated continuous distraction device would be desirable. It has been reported that continuous distraction generates adequate bone with lengthening at a rate of 2 mm/day, thereby reducing the treatment time. The device we describe here uses miniature high-pressure hydraulics, position feedback, and a digital controller to achieve closed-loop control of the distraction process. The implanted actuator can produce up to 40 N of distraction force on linear trajectories as well as curved distraction paths. In this paper we detail the spring-powered hydraulic reservoir, controller, and user interface. Experiments to test the new device design were performed in a porcine cadaver head and in live pigs. In the cadaver head, the device performed an 11 day/11 mm distraction with a root-mean-squared position error of 0.09 mm. The device functioned for periods of several days in each of five live animals, though some component failures occurred, leading to design revisions. The test series showed that the novel design of this system provides the capabilities necessary to automate distraction of the mandible. Further developments will focus on making the implanted position sensor more robust and then on carrying out clinical trials.

FIGURES IN THIS ARTICLE
<>
Copyright © 2009 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Configuration of the new automated distractor

Grahic Jump Location
Figure 2

Implanted distraction device

Grahic Jump Location
Figure 3

Rail supported on four pins

Grahic Jump Location
Figure 4

Position sensor manufactured by Microstrain Inc. (Burlington, VT)

Grahic Jump Location
Figure 5

Control circuit block diagram

Grahic Jump Location
Figure 6

Surgical procedure: (a) device implanted on mandible and (b) external controller attached to the back of the animal

Grahic Jump Location
Figure 7

Tracking performance for Animals 2, 4, and 5

Grahic Jump Location
Figure 8

Tracking performance in cadaver head, with valve pulse period shown. Negative pulse widths correspond to firing the reversing valve.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In