Patient-specific implants (PSIs) are known to yield reliable outcomes in orbital wall fracture reconstruction (high precision, smoother operating techniques, and shorter surgical duration). This study analyzed the surgical error and clinical and esthetic outcomes of orbital reconstructions with PSIs.
This ambispective cohort study enrolled patients who underwent orbital reconstruction using PSIs between October 2016 and January 2018. The study end points were surgical error, indication and duration of surgery, long-term sequelae, revision surgeries, and surgical complications. Surgical error was analyzed by superimposing the postoperative implant position onto the preoperative virtual plan. Both qualitative (heat map) and quantitative (distance) measurements were obtained.
Three patients were enrolled prospectively, and 23 were enrolled retrospectively. Indications for surgery were defect size (25 patients), diplopia (10 patients), impaired eye motility (4 patients), and significant enophthalmos (6 patients). At the last patient visit, there were 5 cases of diplopia, 1 case of exophthalmos, and 6 cases of slight enophthalmos of incremental degree. In terms of surgical error, a mean distance of 0.6 mm (95% confidence interval, 0.49 to 0.76), with a mean maximal distance of 3.4 mm (95% confidence interval, 2.79 to 4.02), was noted. No revision surgery was necessary. Lid malposition complications were not observed. However, 1 case each of symblepharon and scleral show were observed. No time-saving component was observed.
PSI use in orbital reconstruction guarantees a preplanned 3-dimensional anatomical shape with a mean surgical error of just 0.6 mm. Our clinical results were similar to those of other protocols; however, warranting a complex 3-dimensional anatomical shape also in large orbital fractures with a low mean surgical error is feasible by using PSIs.
Patient-specific implants (PSI) are becoming popular among surgeons treating complex orbital fractures. Owing to their location, these common midface fractures can be a challenge to operate on because of their limited view and maneuvering space. Sequelae such as diplopia, ocular motility disturbances, and enophthalmos may arise with or without surgery, with optical neuropathy or blindness being possible complications of these fractures.
Reconstruction of orbital fractures may be performed through a mirroring technique that virtually reconstructs a healthy orbit. , The PSIs are designed using the adapted mirrored orbit and produced using additive titanium manufacturing techniques. , ,
The purpose of this study was to analyze specific PSI features, as they are considered to facilitate the surgical procedure by reducing the operating time and offering a smoother operating technique. Furthermore, the rigidity of PSIs may be a favorable characteristic, especially in cases of large defects or a missing posterior ledge.
The investigators wanted to introduce a new method of 3-dimensional (3D) quality measurements of PSIs and hypothesized that the mean surgical error in orbital reconstruction would be about 1 mm. This would lead to low functional and esthetic complications and shorter time spent in the operating room. Therefore, surgical error was measured, functional and esthetic complications were assessed, and operating room time was calculated.
To address the research purpose of this study, an ambispective cohort design was developed. It was approved by the Institutional Review Board Kantonale Ethikkommission Zürich (ref. no. 2016-00833) and Swissmedics (ref. no. 10000149). All the participants in this study were patients of the University Hospital Zurich; all participants signed an informed consent for further use of their clinical data and/or for the prospective analysis of this study ( Fig 1 ).
The study population included patients who experienced unilateral orbital fractures that were reconstructed with PSIs at the university hospital between October 2016 and January 2018. To be included in the study, patients had to sign a general consent form. Patients had to sign an additional specific declaration of consent for the prospective arm. They also had to be 18 years of age or older. The patients were excluded from the study if they were underage, if there was a significant comorbid disease that contraindicated surgery, if informed consent was missing or it was not possible to obtain informed consent, or if orbital reconstruction was performed without a PSI.
The clinic information system was searched for the clinical and radiological information. All data were imported into electronic case report forms using a web-based software for clinical data capture (secuTrial, interActive Systems, Berlin, Deutschland). This study was monitored by the Department of Clinical Trial Center of the University Hospital Zurich.
PSI Design and Planning
Each implant was virtually designed by a clinician of the Department of Oral-Maxillofacial Surgery. The files in standard tessellation language format were sent to a supplier of medical technology surgical solutions (KLS Martin Group, Tuttlingen, Germany) for the control, edit, and production (using a selective laser melting method) of the PSI. The manufactured implants were not yet sterile and had to be sterilized in the hospital.
Surgical Fracture Repair with PSI
All patients were operated on by consultants from the Department of Oral-Maxillofacial Surgery under general anesthesia, following the disinfection and sterilization protocol of the hospital. A transconjunctival retroseptal approach was used in all cases. The fractured walls were dissected, and all orbital tissue was reduced before insertion of the PSI. A forced duction test was performed before and after implant insertion for the evaluation of ocular motility. The implant was set in the best fit position and secured with 1 screw. For surgical quality control, postoperative computed tomography was performed on the day after surgery.