Rapid Prototyping Technology in Orbital Floor Reconstruction: Application in Three Patients

Abstract

).Rapid prototyping, also known as three-dimensional (3D) printing, is an additive manufacturing technology that allows expedient and accurate reproduction of osseous anatomy. It was originally introduced in the mechanical engineering field during the 1980s and this technology has gained interest in craniomaxillofacial surgery as a tool for assessment and preoperative surgical planning.1,2 For orbital floor fractures, rapid prototyping can provide an accurate anatomical representation of the osseous defect, allowing the clinician to preoperatively adapt a titanium plate for reconstruction. This theoretically reduces the operative time required, risk of orbital plate malposition, poor anatomical contour, and trauma to soft tissues due to multiple insertions during trimming and adaptation of the titanium orbital plate. We propose that the use of rapid prototyping and preoperative plate adaptation can significantly reduce the operative time taken while improving patient outcome. MethodsComputed tomography (CT) data were processed via an imaging software program (e.g., 3D slicer, Osirix [OsirixPixmeo, Bernex, Geneva, Switzerland]), cropped and then exported as a stereolithographic file (.stl) (►Fig. 1) which was then used for fabrication of a 3D model via 3D printing. CT orbital parameters used were 0.5 mm slice thickness, The titanium orbital plate was sterilized before insertion and intraoperative CT imaging was used to assess final titanium plate position. Case 1A 59-year-old female presented to the maxillofacial outpatient department following a mechanical fall resulting in a left orbital floor fracture. Enophthalmos of 2 mm was present and a CT scan revealed a large floor defect (►Figs. 2 and 3). Diplopia was present on upward gaze. A rapid prototyping model was fabricated and a Synthes titanium orbital plate was further adapted preoperatively. The orbital floor was accessed via a mid-lid approach and the modified titanium orbital plate was inserted. No further adaptation of the plate was required and the time taken from insertion of the plate to final fixation was less than 1 minute, as no further adaptation was necessary. Position was confirmed with an intraoperative CT scan (O-arm, Medtronic [Medtronic, Minneapolis, MN]) (►Figs. 4-6). The patient's diplopia and enophthalmos had resolved 2 weeks postoperatively and no complications were noted at the 6th week follow-up. Keywords► rapid prototyping ► 3D printing ► orbital reconstruction AbstractRapid prototyping entails the fabrication of three-dimensional anatomical models which provide an accurate and cost-effective method to visualize complex anatomical structures. Our unit has been using this to assist in the diagnosis, planning, and preoperative titanium plate adaptation for orbital reconstruction surgery following traumatic injury. The aim of this article is to demonstrate the potential clinical and costsaving benefits of this technology.

Application of Rapid Prototyping Technique and Intraoperative Navigation System for the Repair and Reconstruction of Orbital Wall Fractures

“…Orbital cavity reconstruction is an ideal target of the RP technique owing to its anatomical complexity, and many researchers have applied a RP model to reconstruction [ 4 6 7 19 ]. Identifying an anatomical landmark is difficult in cases of large defects due to the thin orbital wall [ 7 15 19 ], Kozakiewicz et al [ 2 ] used an uninjured site as a mirrored RP model template to manufacture a pre-bent titanium implant when performing an orbital inferior wall fracture reconstruction. With a mirrored RP model, however, it was impossible to locate defects in the intraoperative field, and disagreement between the pre-bent titanium implant and the defect site may require the implant to be trimmed and redesigned, which increases the operative time.…”

The accuracy of post-traumatic orbital volume correction using pre-adapted titanium mesh (randomized controlled clinical prospective study)

“…Christopher et al found that direct intraoperative trimming and adaptation may take long operative time depending on the extension of the defect and experience of the surgeon when compared with stl models while preoperative rapid prototyping reduces the intraoperative time, risk of orbital mesh malposition, poor anatomical contour, and trauma to soft tissue because of multiple insertions during trimming and adaptation of the titanium mesh [17] .…”

A Case Series of Rapid Prototyping and Intraoperative Imaging in Orbital Reconstruction

“…The treatment protocol (►Fig. 2) was the same used by an earlier case report by Lim et al 1 Patients who sustained pure orbital floor fractures not involving the zygomatic complex, orbital rim, and/or the medial orbital wall were identified over a 12-month period. Orbital floor defects greater than 1 cm 2 was the parameter required for operative intervention.…”

“…1) leading to a reduction in treatment time, tissue trauma, and restoration of orbital form. 1,5 Hoelzle et al 6 were among the first to document the benefits of intraoperative scanning. It has since been used by some authors with the aim of eliminating malposition of implants and the need for revision surgery in midface trauma.…”