In house virtual surgery and 3D complex head and neck reconstruction

Abstract

Background: 3-Dimensional (3D) printing can be applied to virtual planning and creation of surgical guides for mandibular reconstruction. Such systems are becoming increasingly prevalent in head and neck reconstruction. However, third party access to this technology is costly and removes the opportunity to design, create, and modify the bony reconstructions, as third party technology is a black box. This series is a pilot study to document the feasibility of an in-house software tool. The objectives of this study are to describe the design of an automated in house system and assess the accuracy of this in house automated software tool for mandibular reconstruction in a simulated environment.

Methods: Software was written to automate the preoperative planning and surgical guide creation process. In a simulation lab, Otolaryngology residents were tasked with resecting and reconstructing a simulated mandible using the 3D-printed cutting guides. A control group of residents performed resection and reconstruction using the traditional method without cutting guides. T-test analysis was performed to compare specific aspects of the final reconstructions including: change from native mandibular width and projection, segment gap distance, and reconstruction time.

Results: Mandibular reconstruction was successful in all participants using the 3D printed system. The guided group performed significantly better on the measurement of change in Mandibular overlap, projection, segment gap volume. There was a non-significant trend towards better mandibular width and operative time for the guided group.

Conclusions: This study confirms functionality and feasibility of using an in house automated software for planning and creating surgical guides.

Keywords: 3D printing; Mandibular reconstruction; Stereolithography; Surgical cutting guide.

Fig. 1

The 3D printed surgical guides attached to the diseased mandible and generic fibula. Picture of the 3D printed surgical guides and 3D printed disease mandible. It shows how the surgical guides would attach onto a mandible. The surgical cutting guide is also attached to a generic plastic fibula

Fig. 2

Measurements of accuracy including overlap, projection, width, and gap volume between segments. The reconstructed mandibles were CT scanned and segmented to create models. Mathematical calculations were then performed on the models to determine accuracy. These pictures show which measurements were taken to calculate a. overlap between native and reconstructed mandible, b. the change in projection and width, an c. the gap volume between each segment of the reconstructed mandible

Fig. 3

The anonymized reconstruction results with the native mandible and printed optimal virtually planned reconstruction. This picture show all the reconstructed mandibles with a 3D print out of the original diseased mandible and a printout of the virtually planned reconstruction

Fig. 4

A non-significant decrease in time to completion was shown between the freehand and guided group. This graph shows the time to completion of the reconstructions with 1 line for the freehand group and 1 line for the guided group. There is a non-significant trend to decrease in time for the guided group. Additionally, residents in higher training years performed the reconstruction in less time as expected

Fig. 5

A significant decrease in the differences between the native and reconstructed mandible was shown for overlap and width. This graph compares the accuracy measurements for the reconstructions performed freehand with the reconstructions performed with the guide. There shows a decrease in the change of projection and width with the guided group

Fig. 6

The volume of the gap between osteotomies was significantly decreased in the guided group compared to the freehand group. This figure shows the average volume of the gaps between segments in the guided and freehand group. The volume of gap is greater in the freehand group. This is an important outcome, as a surgeon would want to optimize the bony contact to increase healing