Continuous distraction osteogenesis device with MAAC controller for mandibular reconstruction applications

Abstract

Background: Distraction osteogenesis (DO) is a novel technique widely used in human body reconstruction. DO has got a significant role in maxillofacial reconstruction applications (MRA); through this method, bone defects and skeletal deformities in various cranio-maxillofacial areas could be reconstructed with superior results in comparison to conventional methods. Recent studies revealed in a DO solution, using an automatic continuous distractor could significantly improve the results while decreasing the existing issues. This study is aimed at designing and developing a novel automatic continuous distraction osteogenesis (ACDO) device to be used in the MRA.

Methods: The design is comprised of a lead screw translation mechanism and a stepper motor, placed outside of the mouth to generate the desired continuous linear force. This externally generated and controlled distraction force (DF) is transferred into the moving bone segment via a flexible miniature transition system. The system is also equipped with an extra-oral ACDO controller, to generate an accurate, reliable, and stable continuous DF.

Results: Simulation and experimental results have justified the controller outputs and the desired accuracy of the device. Experiments have been conducted on a sheep jaw bone and results have showed that the developed device could offer a continuous DF of 38 N with distraction accuracy of 7.6 nm on the bone segment, while reducing the distraction time span.

Conclusion: Continuous DF with high resolution positioning control, along with the smaller size of the distractor placed in the oral cavity will help in improving the result of the reconstruction operation and leading to a successful DO procedure in a shorter time period. The developed ACDO device has less than 1% positioning error while generating sufficient DF. These features make this device a suitable distractor for an enhanced DO treatment in MRA.

Keywords: Automatic continuous distractor; Distraction osteogenesis; Medical devices.

Fig. 1

The 3D model of the designed TM

Fig. 2

The lead screw translation mechanism

Fig. 3

The schematic model of the mechatronic part [54]

Fig. 4

The block diagram of the ACDO controller

Fig. 5

The controller circuit of the ACDO device

Fig. 6

The current subsystem

Fig. 7

Speed and position subsystems

Fig. 8

The overall simulation model of stepper motor

Fig. 9

The schematic model of the TS

Fig. 10

The device connected to the sheep jaw bone

Fig. 11

The DF measurement exam

Fig. 12

Simulation results of the stepper motor

Fig. 13

Simulation results of the stepper motor

Fig. 14

The mean measured DT and the MMDL of the tests