Guided zygoma implant surgery and why it should not be considered routine yet

Guided Zygoma implant surgery and why it should not be considered routine yet

by Luc Vrielinck To date, the placement of zygoma implants is considered a routine method in the rehabilitation of patients with severe resorption in the upper jaw and to a lesser extent in (hemi)maxillectomy cases and partial edentulous cases (in the posterior region)1. It is known from clinical experience that correct placement of the tip of zygomatic implant right into the zygoma bone is challenging and sometimes occurs in misplacement of the zygoma with perforation through the floor of the orbit, or retrozygomatic emergence in the infratemporal fossa2.

In view of this problem, use of a surgical drill guide or navigation system has been recommended. Two different approaches are possible: use of surgical guides, already well received in ‘normal’ implantology and navigation techniques using a computer and a tracking device. In addition, clinicians will address three clinical solutions when inserting zygomatic implants: intrasinusal, versus Stella technique, versus extramaxillary zygoma implant placement.

From a technical point of view, preclinical in vitro research (cadaver) concluded that when using a drill guide one can obtain relatively small deviation suggesting the use of a drill guide for zygoma implant placement3. When using techniques of navigation for placement of zygoma implants on phantoms, the resulting deviations were also relatively small4.

These results have however not been confirmed in clinical studies. The deviations noted in the clinical situation are much more variable than recorded in in vitro experiments5.

However, 3D planning of the zygoma implant surgery has a positive effect on the surgeon since he can better prepare or simulate the intended treatment6.

1 Malevez C.: Zygomatic anchorage concept in full edentulism. Rev Stomatol Chir Maxillofac. 2012 Sep;113(4):299-306. doi: 10.1016/j.stomax.2012.06.001. Epub 2012 Aug 2 2 Chrcanovic BR, Abreu MH. Survival and complications of zygomatic implants: a systematic review.

Oral Maxillofac Surg. 2013 Jun;17(2):81-93. doi: 10.1007/s10006-012-0331-z. Epub 2012 May 6.

3 Van Steenberghe D1, Malevez C, Van Cleynenbreugel J, Bou Serhal C, Dhoore E, Schutyser F, Suetens P, Jacobs R. Accuracy of drilling guides for transfer from three-dimensional CT-based planning to placement of zygomaimplants in human cadavers. Clin Oral Implants Res. 2003 Feb;14(1):131-6.

4 Xiaojun C1, Ming Y, Yanping L, Yiqun W, Chengtao W. Image guided oral implantology and its application in the placement of zygoma implants. Comput Methods Programs Biomed. 2009 Feb;93(2):162-73. doi: 10.1016/j.cmpb.2008.09.002. Epub 2008 Oct 31.

5 Vrielinck L1, Politis C, Schepers S, Pauwels M, Naert I. Image-based planning and clinical validation of zygoma and pterygoid implant placement in patients with severe bone atrophy using customized drill guides. Preliminary results from a prospective clinical follow-up study. Int J Oral Maxillofac Surg. 2003 Feb;32(1):7-14.

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Katsoulis J1, Pazera P, Mericske-Stern R. Prosthetically driven, computer-guided implant planning for the edentulous maxilla: a model study. Clin Implant Dent Relat Res. 2009 Sep;11(3):238-45. doi: 10.1111/j.1708-8208.2008.00110.x. Epub 2008 Sep 9.

However the use of a guiding tool (drill guide, navigation system) is not exempt from complications like the risk of an undesirable positioning of the zygoma implant, either intraorbitally or in the infratemporal fossa. The possible occurrence of these serious mishaps undermines the intended benefits of the guided zygoma implant placement. The available data demonstrate that placement of zygoma implant with a guiding tool requires more experience than originally has been assumed. Furthermore, this technique is often more demanding in terms of experience, surgical difficulty, operation time and financial resources than the conventional surgical approach. Therefore, the use of guided zygoma implant placement as a routine procedure for zygoma implant placement is not recommended.

Since the use of guiding tool for placement of zygoma implant does not prevent undesired implant positioning (either intraorbital, or in the infratemporal fossa), two occurrences that an experienced zygoma implant surgeon can easily recognize during surgery, its use should not be recommended. Instead, adequate operative visualization of the surgical field by an experienced surgeon should be preferred.