gms | German Medical Science

81. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V.

Deutsche Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V.

12.05. - 16.05.2010, Wiesbaden

Computer assisted surgery of orbital wall fractures

Meeting Abstract

  • corresponding author presenting/speaker Frank Wilde - Dept. of CMF, Military and Academic Hospital Ulm, Academic Hospital Ulm University, Ulm, Germany
  • Kai Lorenz - Dept. of ENT, Military and Academic Hospital Ulm, Academic Hospital Ulm University, Ulm, Germany
  • Lukas Kamer - AO Development institute, AO foundation, Davos, Switzerland
  • Heinz Maier - Dept. of ENT, Military and Academic Hospital Ulm, Academic Hospital Ulm University, Ulm, Germany
  • Beat Hammer - Cranio Facial Center, Hirslanden Medical Center, Aarau, Switzerland
  • Marc Metzger - Dept. of CMF, University Hospital Freiburg, Germany
  • Nils-Claudius Gellrich - Dept. of CMF, Medical School Hannover, Germany
  • Rainer Schmelzeisen - Dept. of CMF, University Hospital Freiburg, Germany
  • Alexander Schramm - Dept. of CMF, Military and Academic Hospital Ulm, Academic Hospital Ulm University, Ulm, Germany

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. 81st Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. Wiesbaden, 12.-16.05.2010. Düsseldorf: German Medical Science GMS Publishing House; 2010. Doc10hno103

DOI: 10.3205/10hno103, URN: urn:nbn:de:0183-10hno1035

Veröffentlicht: 6. Juli 2010

© 2010 Wilde et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Purpose: Computer-assisted preoperative planning and surgery is still not part of the surgical routine in the field of traumatic orbital defects, yet. The first challenge is the evaluation of the defect pattern. The second is the surgical procedure by itself. 3D imaging techniques provide extensive possibilities for the detailed and precise analysis of the whole craniofacial complex. But in cranio-maxillo-facial surgery still remains a lack of intraoperative control of the achieved surgical results. Intraoperative navigation helps to guide the surgeon to the preplaned result without any extra radiation. Due to the introduction of 3D C-arm devices there is now the possibility to use intraoperative 3D imaging in CMF as well.

Methods: Imaging, planning and navigation techniques in our clinical centres serve for computer assisted preoperative planning and computer assisted surgery. The orbital defects of the patients were assessed in multiplanar (axial, coronal, sagittal) and 3D views. The orbital reconstructions were performed with the workflow: (1) Preoperative planning and virtual reconstruction using a new software tool for automatic bone segmentation of standard computer tomography (CT) data sets (Brainlab®, Germany). Virtual correction by mirroring the segmented orbit of the not affected side to the affected side for simulation of ideal the reconstruction (Figure 1 [Fig. 1]). Selection of the ideal preformed titanium orbital mesh (Synthes®, Switzerland) preoperatively by importing the implant in the data set and checking the fit virtually (Figure 2 [Fig. 2]). (2) Intraoperative navigation and guiding of the reconstructive procedure by inserting the preformed titanium mesh mentioned above using a transconjunctival approach. Intraoperative navigation was done using frameless stereotaxy (Figure 3 [Fig. 3]). The virtual patient and the real patient were correlated with an individual registration system (Brainlab®, Germany). (3) Intraoperative 3D imaging with a 3D-C-arm cone beam computer tomograph (CBCT) (Siemens®, Germany). (4) Immediate image fusion of the CBCT scan with the preoperative virtual planning to control the achieved result (Brainlab®, Germany) and therefore replacing any postoperative imaging (Figure 4 [Fig. 4]).

Results: The described workflow leads to intraoperative prediction of the postsurgical outcome. The new software tool for automatic bone segmentation of standard CT data sets reduces the period of time for preoperative planning in virtual facial reconstruction significantly. Mirroring the segmented orbit of the not affected side to the affected side achieves instant and exact virtual reconstruction of orbital wall defects in form of a virtual template for later surgery. Checking the fit of the preformed titanium mesh virtually enables to select the wright mesh size. Also, cutting of of unnecessary parts of the mesh before insertion in the orbit can be planned on the computer platform. This reduced operation time and minimized the risk of sequelas like injuries to periorbital tissues, the eyeball itself and the lower eyelid by reducing the manipulation of these structures during surgery. Intraoperative navigation using the preoperative planned virtual model for guiding of the reconstructive procedure supported the achievement of the desired result in complicated cases, where the positioning of the implant had to be proven several times. The direct intraoperative radiological 3D control with a 3D-C-arm CBCT and immediate image fusion with the preoperative planning enabled the surgeon to control his reconstruction result intraoperatively.

Conclusion: This new method improves surgeon’s confidence in orbital wall reconstructions. The presented workflow in orbital wall reconstruction have led to clinical routine in our specialized clinical centre due to predictable anatomically reconstruction results.