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Comparative Study
. 2025 Nov 26;21(1):88.
doi: 10.1186/s13005-025-00569-8.

Comparison of the accuracy between guided and freehand placement of periorbital implants-a cadaveric split-face study

Britta M Lohn  1 , Stefan Raith  2 , Philipp Winnand  2 , Mark Ooms  2 , Tino Rickert  2 , Nina Wagenknecht  2 , Frank Hölzle  2 , Ali Modabber  2
Affiliations
Comparative Study

Comparison of the accuracy between guided and freehand placement of periorbital implants-a cadaveric split-face study

Britta M Lohn et al. Head Face Med. .

Abstract

Background: Orbital exenteration (exenteratio orbitae) is a disfiguring procedure performed with tumor resection. Rapid realization of an implant-retained craniofacial prosthesis with a secure fit for an active life is essential to restore quality of life. Osseointegrated implants are commonly used for maxillofacial rehabilitation. The precise positioning of these implants is more difficult in cases of reduced bone availability, but it enables anaplastologists to achieve an unobtrusive restoration.

Methods: After computed tomography (CT) scans of 13 cadaver heads, 104 craniomaxillofacial (CMF) implants were digitally planned. Using a split-face study design, one periorbital side was treated with customized surgical guides and one side was operated freehand. The digital evaluation of position, axis, and insertion depth compared to the digital planning was conducted for 78 periorbital implants using digital evaluation of a postoperative CT scan to measure the linear and angular deviation from preoperative planning.

Results: The linear deviation in 3D (p = 0.0105), drilling depth (p = 0.0013), and angular deviation (p = 0.0004) were significantly greater in the freehand group than in the guided computer-assisted implant surgery (CAIS) group.

Conclusion: Digital planning enables the available bone support to be preoperatively estimated. CAIS with surgical guides offers significantly more accurate results for CMF implant placement than a freehand transfer of digital planning. Guided CAIS requires a larger surgical approach and therefore fails to achieve the goal of a minimally invasive technique.

Keywords: Anaplastology; CMF implants; Craniofacial prosthesis; Epithesis; Extraoral implantology; Surgical template.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: Ethical approval was granted by the Ethics Committee of the Medical Faculty of RWTH Aachen University (EK219/16). All procedures involving human cadavers were performed in accordance with institutional and national guidelines. The handling, storage, and use of cadaver samples were carried out in accordance with ISO 12891 standards, ensuring appropriate safety measures, proper documentation, and respectful treatment of donors. All body donors bequeathed their bodies to science during their lifetime. The study was conducted in accordance with the Declaration of Helsinki. The authors wish to sincerely thank those who donated their bodies to science so that anatomical research could be performed. Results from such research can potentially improve patient care and increase mankind’s overall knowledge. Therefore, these donors and their families deserve our highest gratitude. Consent for publication: Not applicable. Competing interest: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Digital planning in CoDiagnostiX™ (DentalWings, Montréal, Canada) with the imported STL file of the AHEAD implant (L 6 mm; Ø4mm; Biocomp Industries Vught, Netherlands), which show the marked distances between the supra- and infraorbital implants and the implant axis in extension (yellow)
Fig. 2
Fig. 2
a Digital planning using Blender software (version 3.5; Blender Foundation, Amsterdam, Netherlands) (green bone-supported template; red soft-supported template). b Bone-supported template for the infraorbital rim of the left orbit linked to the soft tissue-supported monocle with extension to the area of the nasion. The supraorbital skin markings in the semicircular anchors also serve as a connection between the bone and the soft tissue element according to the tongue and groove principle
Fig. 3
Fig. 3
a Drilling guided by the drilling log. b Implant insertion using a ratchet
Fig. 4
Fig. 4
a Treatment evaluation using CoDiagnostiX™ (DentalWings, Montréal, Canada) with a semi-automated overlay of the implemented implant planning in the postoperative CT scan (blue) and preoperatively planned position (red). b Schematic representation of the angular deviation (in °), the linear deviation in both the entry point and at the apex position, the error of depth insertion at both the implant shoulder and the apex
Fig. 5
Fig. 5
a Linear deviation (in mm) and b angular deviation (in °) from the virtual plan separately for freehand (F) and guided (G) implant placement. Data are presented as bar columns (median) with interquartile range lines. Differences between groups were analyzed with the paired Wilcoxon-test
See this image and copyright information in PMC

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