Is there more to the clinical outcome in posttraumatic reconstruction of the inferior and medial orbital walls than accuracy of implant placement and implant surface contouring? A prospective multicenter study to identify predictors of clinical outcome

Insights into Orbital Symmetry: A Comprehensive Retrospective Study of 372 Computed Tomography Scans

Background: The operation planning and production of individualized implants with the help of AI-based software after orbital fractures have become increasingly important in recent years. This retrospective study aimed to investigate the healthy orbitae of 372 patients from CT images in the bone and soft tissue windows using the Disior™ Bonelogic™ CMF Orbital software. (version 2.1.28). Methods: We analyzed the variables orbital volume, length, and area as a function of age and gender and compared bone and soft tissue windows. Results: For all variables, the intraclass correlation showed excellent agreement between the bone and soft tissue windows (p < 0.001). All variables showed higher values when calculated based on bone fenestration with, on average, 1 mL more volume, 0.35 mm more length, and 0.71 cm2 more area (p < 0.001). Across all age groups, men displayed higher values than women with, on average, 8.1 mL larger volume, a 4.78 mm longer orbit, and an 8.5 cm2 larger orbital area (p < 0.001). There was also a non-significant trend in all variables and both sexes toward growth with increasing age. Conclusions: These results mean that, due to the symmetry of the orbits in both the bone and soft tissue windows, the healthy orbit can be mirrored for surgical planning in the event of a fracture.

Intraoperative Computed Tomography Use in Orbital Fracture Repair: A Systematic Review and Meta-Analysis

Background: Intraoperative computed tomography (CT) allows surgeons to make adjustments during orbital fracture repair that may impact postoperative outcomes. Learning/Study Objectives: To determine the impact of intraoperative CT use on intraoperative revision and surgical outcomes for orbital fracture repair. Methods: A systematic review was performed in concordance with the Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines: the population was patients undergoing orbital fracture repair; intervention was use of intraoperative CT; comparison was patients not undergoing intraoperative CT; and outcomes were intraoperative revision rate, postoperative complications, and secondary revision surgeries. Meta-analysis was performed on the rate of intraoperative revision. Results: The search criteria yielded 790 articles, 377 were eligible for review, and 20 articles met criteria for analysis. In 19, intraoperative imaging led to immediate surgical corrections, with a random pooled effect size of 0.27 (0.20-0.35). Six studies reported secondary revision surgery rates (range 0-10.5%), and six studies reported postoperative complication rates (range 10-30%). Conclusions: Intraoperative imaging helps surgeons make precise, real-time adjustments in 27% of orbital fracture repair cases, which may improve surgical outcomes; however, more research is needed to investigate its impact on health care costs, operating time, and radiation exposure.

Patient Specific Implants for Orbital Reconstruction in the Treatment of Silent Sinus Syndrome: Two Case Reports

Silent sinus syndrome is a rare disorder characterized by ipsilateral enophthalmos and hypoglobus following a collapse of the orbital floor, in the presence of asymptomatic long-term maxillary sinusitis. It results in enophthalmos, hypoglobus and deepening of the superior palpebral sulcus. A standardized treatment protocol for this infrequent syndrome has not yet been established. The management includes restoration of maxillary sinus ventilation with functional endoscopic sinus surgery and orbital reconstruction, either concurrently or separately. In this paper, the authors presented two patients successfully treated with patient-specific implants, and intraoperative navigation. These cases highlight the benefit of computer-assisted planning and titanium patient-specific implants in the management of silent sinus syndrome. To the best of our knowledge, this is the first report that described the use of PSI with titanium spacers performed with the aid of intraoperative navigation for SSS treatment. Advantages, drawbacks of this technique and treatment alternatives currently available in the literature were also discussed.

Accuracy of intraoperative navigation for orbital fracture repair: A retrospective morphometric analysis

In this retrospective case series, patients undergoing surgery to treat isolated orbital floor fractures were morphometrically analyzed. Cloud Compare was used to compare mesh positioning with a virtual plan, using the distance-to-nearest-neighbor method. To assess the accuracy of mesh positioning, a mesh area percentage (MAP) parameter was introduced and three distance ranges were defined as the outcome measures: the 'high-accuracy range' included MAPs at a distance of 0-1 mm from the preoperative plan; the 'intermediate-accuracy range' included MAPs at a distance of 1.1-2 mm from the preoperative plan; the 'low-accuracy range' included MAPs at a distance of >2 mm from the preoperative plan. To complete the study, morphometric analysis of the results was combined with clinical judgment ('excellent', 'good', or 'poor') of mesh positioning by two independent blind observers. In total, 73 of 137 orbital fractures met the inclusion criteria. In the 'high-accuracy range' the mean, minimum, and maximum MAP values were 64%, 22%, and 90%, respectively. In the 'intermediate-accuracy range', the mean, minimum, and maximum values were 24%, 10%, and 42%, respectively. In the 'low-accuracy range', the values were 12%, 1%, and 48%, respectively. Both observers classified 24 cases of mesh positioning as 'excellent', 34 as 'good', and 12 as 'poor'. Within the limitations of the study, it seems that virtual surgical planning and intraoperative navigation has the potential to add quality to the repair of the orbital floor and, therefore, should be taken into consideration whenever appropriate.

Prospective Evaluation of Two Wall Orbital Fractures Involving the Medial Orbital Wall: PSI Reconstruction versus PDS Repair—Worth the Effort?

Proper treatment of the two-wall fractured orbit is still controversial. Specifically, there is no consensus on the issue of the necessity of medial orbital wall repair. With anatomically critical structures at risk during the surgical approach, surgeons’ view on the necessity of medial orbital wall repair often is restricted and an aesthetically disturbing enophthalmos is more likely to be accepted. Therefore, treatment options range from leaving the medial wall without repair to reconstruction with autogenous tissue or alloplastic materials, which can lead to moderate to severe side effects. However, emerging technologies such as patient-specific implants (PSI) offer a reliable and anatomically correct reconstruction of the bony orbit. This study aimed to evaluate the outcome of full orbital reconstruction using PSIs compared to only orbital floor repair using PDS (bioresorbable polydioxanone) foils leaving the medial orbital wall untouched in traumatic two-wall orbital fractures. Of all patients treated at the University Hospital of Düsseldorf between 2017 and 2019 who suffered from traumatic orbital fracture, only patients with a two-wall orbital fracture involving both the orbital floor and the medial wall (n = 68) were included. Patients were treated either with a PSI (n = 35) or a PDS foil (n = 33). Primary outcome parameters were ophthalmological disturbances analyzed via clinical investigation and intra-orbital angles, volumes and implant position analyzed with radiological 3D-datasets. While a two-wall reconstruction using PSIs led to a significant improvement of the enophthalmos, the rate of postoperative enophthalmos was significantly increased in cases of only orbital floor repair with PDS foils. Radiologically, a significant reconstruction of the three-dimensional bony orbit succeeded with the simple use of PSIs leading to a significant reduction in the traumatically enlarged orbital volume. PSI also led to a significant reduction in the traumatically enlarged medial angle of the orbit. This was not the case for single-floor repair with PDS foil. The results of this study suggest that complex orbital fractures can be reconstructed at an even higher degree of accuracy with selective laser-melted PSIs than PDS foils. In order to achieve a true to original reconstruction of the bony orbit, surgical treatment of the medial orbital wall can be advocated for in the long term depending on the indication.

Personalized Medicine Workflow in Post-Traumatic Orbital Reconstruction

Restoration of the orbit is the first and most predictable step in the surgical treatment of orbital fractures. Orbital reconstruction is keyhole surgery performed in a confined space. A technology-supported workflow called computer-assisted surgery (CAS) has become the standard for complex orbital traumatology in many hospitals. CAS technology has catalyzed the incorporation of personalized medicine in orbital reconstruction. The complete workflow consists of diagnostics, planning, surgery and evaluation. Advanced diagnostics and virtual surgical planning are techniques utilized in the preoperative phase to optimally prepare for surgery and adapt the treatment to the patient. Further personalization of the treatment is possible if reconstruction is performed with a patient-specific implant and several design options are available to tailor the implant to individual needs. Intraoperatively, visual appraisal is used to assess the obtained implant position. Surgical navigation, intraoperative imaging, and specific PSI design options are able to enhance feedback in the CAS workflow. Evaluation of the surgical result can be performed both qualitatively and quantitatively. Throughout the entire workflow, the concepts of CAS and personalized medicine are intertwined. A combination of the techniques may be applied in order to achieve the most optimal clinical outcome. The goal of this article is to provide a complete overview of the workflow for post-traumatic orbital reconstruction, with an in-depth description of the available personalization and CAS options.

Prospective Evaluation of Intraorbital Soft Tissue Atrophy after Posttraumatic Bone Reconstruction: A Risk Factor for Enophthalmos

Orbital fractures are a common finding in facial trauma, and serious complications may arise when orbital reconstruction is not performed properly. The virtual planning can be used to print stereolithographic models or to manufacture patient-specific titanium orbital implants (PSIs) through the process of selective laser melting. This method is currently considered the most accurate technique for orbital reconstruction. Even with the most accurate techniques of bone reconstruction, there are still situations where enophthalmos is present postoperatively, and it may be produced by intraorbital soft tissue atrophy. The aim of this paper was to evaluate the orbital soft tissue after posttraumatic reconstruction of the orbital walls’ fractures. Ten patients diagnosed and treated for unilateral orbital fractures were included in this prospective study. A postoperative CT scan of the head region with thin slices (0.6 mm) and soft and bone tissue windows was performed after at least 6 months. After data processing, the STL files were exported, and the bony volume, intraorbital fat tissue volume, and the muscular tissue volume were measured. The volumes of the reconstructed orbit tissues were compared with the volumes of the healthy orbit tissues for each patient. Our findings conclude that a higher or a lower grade of fat and muscular tissue loss is present in all cases of reconstructed orbital fractures. This can stand as a guide for primary or secondary soft tissue augmentation in orbital reconstruction.

Primary reconstruction of extensive orbital fractures using two-piece patient-specific implants: the Helsinki protocol

PURPOSE

We present our experience of titanium-milled two-piece patient-specific implants (PSIs) for primary reconstructions of extensive orbital floor and medial wall fractures (EOFMFs) and evaluate their postoperative functional and aesthetic outcomes in relation to commercially available implants.

METHODS

We included all patients with primary reconstructions (< 22 days from injury) of EOFMFs treated in our department between January 2011 and October 2020. Extensive orbital floor and medial wall fracture was defined as involvement of orbital floor, medial wall and maxilloethmoidal junction; a fracture defect 5 mm or more; defect size more than a third of both inferior and medial walls; and Jaquiéry classification III or more. Patient characteristics, details of fracture defects and surgeries, postoperative outcomes and implant positions were retrospectively evaluated and compared between study groups.

RESULTS

Nineteen patients were included: 5 with two-piece PSIs and 14 with commercial implants. Implant position was good in 4/5 patients with two-piece PSIs and 2/14 with commercial implants. Revision surgery, globe malposition (GMP) > 2 mm, significant diplopia and poor implant position were more frequent in patients with commercial implants than two-piece PSIs. None of the patients with a good overall implant position had any significant postoperative symptoms.

CONCLUSION

Extensive orbital fracture reconstructions are somewhat rare, and surgical treatment is associated with a high rate of complications and postoperative symptoms. Titanium-milled two-piece PSIs are well suited for primary reconstructions of EOFMFs, as they lead to more precise reconstructions and fewer postoperative symptoms than commercially available implants.

Preliminary outcomes of the surgical navigation system combined with intraoperative three-dimensional C-arm computed tomography for zygomatico-orbital fracture reconstruction

This study analyzed the outcomes of zygomatico-orbital fracture reconstruction using the real-time navigation system with intraoperative three-dimensional (3D) C-arm computed tomography (CT). Fifteen patients with zygomatico-orbital or isolated orbital/zygoma fractures were enrolled in this prospective cohort. For zygoma reduction, the displacement at five key sutures and the differences between preoperative and intraoperative CT images were compared. For orbital reconstruction, the bilateral orbital volume differences in the anterior, middle, and posterior angles over the medial transitional buttress were measured. Two patients required implant adjustment once after the intraoperative 3D C-arm assessment. On comparing the preoperative and postoperative findings for the zygoma, the average sum of displacement was 19.48 (range, 5.1–34.65) vs. 1.96 (0–3.95) mm (P < 0.001) and the deviation index was 13.56 (10–24.35) vs. 2.44 (0.6–4.85) (P < 0.001). For the orbit, the mean preoperative to postoperative bilateral orbital volume difference was 3.93 (0.35–10.95) vs. 1.05 (0.12–3.61) mm³ (P < 0.001). The mean difference in the bilateral angles at the transition buttress was significantly decreased postoperatively at the middle and posterior one-third. There was no significant difference in orbital volume, angle of the transition zone, and the sum of five zygoma distances between post operative results and preoperative virtual planning. The surgical navigation system with the intraoperative 3D C-arm can effectively improve the accuracy of zygomatico-orbital fracture reconstruction and decrease implant adjustment times.

Approach to Orbital Fractures After Athletic Injuries

The bony orbit is commonly involved in athletic injuries. Evaluation should include a comprehensive history and ocular examination. Computed tomography imaging is the gold standard for diagnostic testing. Urgent surgical intervention for orbital floor fractures should occur after "white eye" trapdoor fractures or if oculocardiac response occurs. Most orbital fractures do not require urgent intervention and repair can be completed within 2 weeks of injury. There are many approaches to repair orbital fractures, and consideration of techniques depends on the unique fracture pattern. Intraoperative computed tomography has become frequently used and can lead to increased identification of plate malpositioning intraoperatively.

Technical Note on Three- and Four-Wall Orbital Reconstructions with Patient-Specific Implants

ABSTRACT

Orbital reconstruction is one of the most complex procedures in maxillofacial surgery. It becomes even more complex when all references to the original anatomy are lost. The purpose of this article is to provide an overview of techniques for complex three- and four-wall orbital reconstructions. Preoperative virtual surgical planning is essential when considering different reconstruction possibilities. The considerations that may lead to different approaches are described, and the advantages and drawbacks of each technique are evaluated. It is recommended to reconstruct solitary three-wall or four-wall orbital defects with multiple patient-specific implants. Optimizations of this treatment protocol are suggested, and their effects on predictability are demonstrated in a case presentation of a four-wall defect reconstruction with multiple patient-specific implants.

Critical appraisal of patient-specific implants for secondary post-traumatic orbital reconstruction

In orbital reconstruction, a patient-specific implant (PSI) may provide accurate reconstruction in complex cases, since the design can be tailored to the anatomy. Several design options may be embedded, for ease of positioning and precision of reconstruction. This study describes a cohort of 22 patients treated for secondary orbital reconstruction with a PSI; one patient received two PSI. The preoperative clinical characteristics and implant design options used are presented. When compared to preoperative characteristics, the postoperative clinical outcomes showed significant improvements in terms of enophthalmos (P < 0.001), diplopia (P < 0.001), and hypoglobus (P = 0.002). The implant position in all previous reconstructions was considered inadequate. Quantitative analysis after PSI reconstruction showed accurate positioning of the implant, with small median and 90th percentile deviations (roll: median 1.3°, 90th percentile 4.6°; pitch: median 1.4°, 90th percentile 3.9°; yaw: median 1.0°, 90th percentile 4.4°; translation: median 1.4 mm, 90th percentile 2.7 mm). Rim support proved to be a significant predictor of roll and rim extension for yaw. No significant relationship between design options or PSI position and clinical outcomes could be established. The results of this study show the benefits of PSI for the clinical outcomes in a large cohort of secondary post-traumatic orbital reconstructions.

[Complex reconstructions in the facial and cranial regions]

Posttraumatic reconstruction of the neurocranium and viscerocranium is an essential part of modern oral and maxillofacial surgery, in addition to oncological surgery, surgery of congenital craniofacial deformities and dental surgery. Due to the complex anatomy of the facial skull and significant esthetic and functional demands on its reconstruction, reconstructive trauma surgery in this area places the highest demands on the surgeon. This is all the more true if definitive craniomaxillofacial surgical treatment can sometimes only be performed with considerable delays for the benefit of other life-threatening injuries. In order to take these prerequisites into account, achievements of modern biomedical technology, such as intraoperative real-time navigation, computer-assisted planning and computer-assisted manufacturing (CAD/CAM) of patient-specific biomodels and implants, came up early for use in oral and maxillofacial surgery. In combination with intraoperative three-dimensional imaging, these methods result in a treatment pathway tailored to the individual patient, which is directly checked for quality at every step and thus ensures the best possible result for the patient. The use of these technologies extends far beyond the original indications in the area of orbital reconstruction and restoration of bony defects with simple geometry, such as skull defects. Nowadays, even the most complex pan-facial fractures can be restored esthetically and functionally by means of digitalized preliminary planning and individualized skull, orbital and zygomatic implants as well as total temporomandibular joint prostheses.

Accuracy of free-hand positioned patient specific implants (PSI) in primary reconstruction after inferior and/or medial orbital wall fractures

BACKGROUND

To assess the accuracy with which CAD/CAM-fabricated patient-specific titanium implants (PSI) are positioned for inferior and/or medial orbital wall reconstruction without the use of intraoperative navigation.

METHODS

Patients who underwent a primary reconstruction of the orbital walls with PSI due to fractures were enrolled in this retrospective cohort analysis. The primary outcome variables were the mean surface distances (MSD) between virtually planned and postoperative PSI position and single linear deviations in the x-, y- and z-axis at corresponding reference points. Secondary outcome variables included demographic data, classification of orbital wall defects and clinical outcomes.

RESULTS

A total of 33 PSI (orbital floor n = 22; medial wall, n = 11) were examined in 27 patients. MSD was on a comparable level for the orbital floor and medial wall (median 0.39 mm, range 0.22-1.53 mm vs. median 0.42 mm, range 0.21-0.98 mm; p = 0.56). Single linear deviations were lower for reconstructions of the orbital floor compared to the medial wall (median 0.45 vs. 0.79 mm; p < 0.05). There was no association between the occurrence of diplopia and the accuracy level (p = 0.418).

CONCLUSIONS

Free-hand positioning of PSI reaches a clinically appropriate level of accuracy, limiting the necessity of navigational systems to selected cases.

A Functional Radiological and Soft Tissue Classification to Predict Outcomes in Orbital Fracture Surgery in a Multidisciplinary "Real-World" Setting

Purpose: The decision for open reduction and internal fixation (ORIF) of orbital fractures is usually based on clinical severity and soft tissue and bony findings. This study aimed to identify prognostic factors for a successful surgical outcome.

Materials and Methods: We included all orbital fractures treated by ORIF referred to the Ophthalmology clinic for assessment over a 12-year period. A successful outcome was defined as (i) a single operation, (ii) improved diplopia and globe position at 6 months, (iii) no surgical complications, and (iv) patient satisfaction. Data was collected on presenting symptoms, orthoptic measurements, time interval from injury to surgery, fracture geometry and involvement of internal, and external bony landmarks. Univariate and multivariate regression was used to identify predictive factors for success.

Results: There were 143 cases with median age 35.4 years and 81.8% (117/143) male. 51% (73/143) were complex fractures involving multiple orbital walls. 63.6% (91/143) achieved significant improvement in both enophthalmos and diplopia at 6 months. 15.3% (22/143) had significant preoperative soft tissue or neurogenic injury. 11.8% (17/143) required orbital plate repositioning or removal. 1.4% (2/143) developed orbital haematoma and 4.2% (6/143) had cicatricial entropion. Pre-operative nerve or muscle damage (OR 0.05, p = 0.01) and infraorbital fissure fracture (OR 0.38, p = 0.04) were associated with poor outcomes, whereas an intact posterior ledge was associated with successful outcomes (OR 3.03, p = 0.02).

Conclusion: Careful ocular motility evaluation to ascertain neurogenic injury and muscle compartment syndrome, and radiological analysis of the integrity of the posterior ledge and the inferior orbital fissure can facilitate management and expectations of ORIF surgery.

A Rare Case of Cyclotorsion Due to Medial Rectus Displacement Following Orbital Trauma

We describe a rare case of cyclotorsion likely secondary to medial rectus and inferior rectus pathology in a patient with orbital trauma. Sequential orthoptic measurements including Hess charts are presented alongside relevant sections of the orbital CT scans over the course of the patient’s treatment. Following the insertion of a plate to repair an orbital floor fracture, the patient developed cyclotorsion. A combined approach of sequential orthoptic assessment and imaging revealed the likely underlying mechanism. Inferior rectus mechanical restriction combined with displacement of the medial rectus pulley appear to be the likely culprits. Once the orbital plate was exchanged for a smaller sized plate the patient’s symptoms and clinical features resolved. Although orbital plate malpositioning is not an uncommon event, medial rectus deviation as a cause of cyclotorsion has not previously been described. We discuss the alternative differentials for patients with similar orthoptic findings and how they were excluded.

[Competence and communication in the implementation of computer-assisted surgical planning]

In the past the planning of surgical interventions in oral and maxillofacial surgery was based on the clinical picture with the assistance of conventional 2‑dimensional X‑ray images. In cases in which the occlusion was affected, plaster cast models of the jaws were included as a planning aid. With introduction of computed tomography (CT) and the possibility to obtain a 3-dimensional picture of bony structures, it was possible for the first time to construct a virtual image of bony structures and therefore of traumatic, iatrogenic and congenital deformities. Using stereolithographic models, these 3‑dimensional relationships were easily "understandable". Risks could be better classified in the planning of an operative intervention and these models could be used as a basis for communication. It was also possible to use the data acquired by CT for design and construction of so-called CAD/CAM patient-specific implants and to implant them; however, the resolution of the data sets and thus the level of detail did not yet correspond to the current standard, so that "delicate" structures could not be constructed. With the improvement of the resolution of CT and the possibility of additive construction processes, such as the selective laser melting (SLM) process or the 3D printing process, the improvement of precision and shaping of the implant practically without limits became reality. Through the bundling of competencies on both sides, engineer and physician, complex computer-aided planning has now become possible. The basis for this is precise communication to avoid errors in the planning process, which in particular needs individual patient information, e.g. about the structure and quality of the overlying soft tissues.

Self-centering second-generation patient-specific functionalized implants for deep orbital reconstruction

Deep and complete reconstruction of the orbital cavity has been shown to be essential for preventing enophthalmos and hypoglobus in patients with orbital defects or deformities. Additively manufactured patient-specific titanium implants provide unlimited options in design. However, implant malpositioning can still occur, even when intraoperative imaging and navigation are used. In this study, we investigated novel orbital implants containing features facilitating self-centering. Accuracy of implant placement and reconstruction of the orbital dimensions were compared retrospectively between self-centering second-generation patient-specific functionalized orbital implants (study group) and CAD-based individualized implants (control group). Design features of implants in the study group included functionalization with navigation tracks, a preventive design, and flanges - so called stabilizers - towards opposite orbital walls. Implant position was evaluated by fusion of preoperative virtual plans and the post-therapeutic imaging. Aberrances were quantified by 3D heatmap analysis. 31 patients were assigned to the study group and 50 to the control group, respectively. In the study group, most implants were designed with either one (n = 18, 58.06%) or two (n = 10, 32.26%) stabilizers. Twice (6.45%), one stabilizer had to be shortened intraoperatively. Implant fit analysis revealed a significantly more precise (p < 0.001) positioning in the study group (n = 22/31) than in the control group (n = 42/50). Self-centering second-generation patient-specific functionalized orbital implants showed significantly more accurate implant positioning, facilitating the transformation of virtual plans into patient's anatomy. The presented design provides an additional instrument for intraoperative quality control besides intraoperative imaging and navigation.

Prediction of surface area size in orbital floor and medial orbital wall fractures based on topographical subregions

OBJECTIVE

This retrospective study evaluates the occurrence and frequency of different fracture patterns in a series of computed tomography (CT) scans in terms of the AOCMF Trauma Classification (TC) orbit module and correlates the assigned defects with measurements of the fracture area in order to get an approximate guideline for fracture size predictions on the basis of the classification.

MATERIAL AND METHODS

CT scans of patients with orbital floor fractures were evaluated using the AOCMFTC to determine the topographical subregions. The coding consisted of: W = orbital wall, 1 = anterior orbit, 2 = midorbit, i = inferior, m = medial. The 3-dimensional surface area size of the fractures was quantified by the "defect body" method (Brainlab, Munich, Germany). The fracture area size and its confidence and prediction interval within each topographical subregion was estimated by regression analysis.

RESULTS

A total of 137 CT scans exhibited 145 orbital floor fractures, which were combined with 34 medial orbital wall fractures in 31 patients. The floor fractures - W1(i)2(i) (n = 86) and W1(i) (n = 19) were the most frequent patterns. Combined floor and medial wall fractures most frequently corresponded to the pattern W1 (im)2 (im) (n = 15) ahead of W1 (im) 2(i) (n = 10). The surface area size ranged from 0.11 cm² to 6.09 cm² for orbital floor and from 0.29 cm² to 5.43 cm² for medial wall fractures. The prediction values of the mean fracture area size within the subregions were computed as follows: W1(i) = 2.25 cm², W2(i) = 1.64 cm², W1(i)2(i) = 3.10 cm², W1(m) = 1.36 cm², W2(m) = 1.65 cm², W1(m)2(m) = 2.98 cm², W1 (im) = 3.35 cm², W1 (im) 2(i) = 4.63 cm², W1 (im)2(m) = 4.06 cm² and W1 (im)2 (im) = 7.16 cm².

CONCLUSION

The AOCMFTC orbital module offers a suitable framework for topographical allocation of fracture patterns inside the infero-medial orbital cavity. The involvement of the subregions is of predictive value providing estimations of the mean 3-D fracture area size.

Implant-oriented navigation in orbital reconstruction part II: preclinical cadaver study

In orbital reconstruction, the acquired position of an orbital implant can be evaluated with the aid of intraoperative navigation. Feedback of the navigation system is only obtained after positioning of the implant: the implant's position is not tracked in real time during positioning. The surgeon has to interpret the navigation feedback and translate it to desired adjustments of the implant's position. In a previous study, a real-time implant-oriented navigation approach was introduced and the system's accuracy was evaluated. In this study, this real-time navigation approach was compared to a marker-based navigation approach in a preclinical set-up. Ten cadavers (20 orbital defects) were reconstructed twice, by two surgeons (total: 80 reconstructions). Implant positioning was significantly improved in the real-time implant-oriented approach in terms of roll (2.0° vs. 3.2°, P=0.03), yaw (2.2° vs. 3.4°, P=0.01) and translation (1.3mm vs. 1.8mm, P=0.005). Duration of the real-time navigation procedure was reduced (median 4.5 min vs. 7.5 min). Subjective appreciation of the navigation technique was higher for real-time implant-oriented navigation (mean 7.5 vs. 9.0). Real-time implant-oriented navigation feedback provides real-time, intuitive feedback to the surgeon, which leads to improved implant positioning and shortens duration of the navigation procedure.

Current Strategies in Post-traumatic Orbital Reconstruction

Posttraumatic orbital reconstruction is one of the most fascinating fields in reconstructive craniomaxillofacial surgery. Hardly any other field in craniomaxillofacial surgery has changed so much in terms of diagnostics, biomaterial selection for reconstruction, surgical techniques including approaches and quality control. In particular, in the field of reconstructive orbital surgery all advances in modern medical treatment are summarized and represented. Reconstructive orbital surgery thus became the medical field spearheading all reconstructive surgical specialties in terms of use of DICOM-data, computer assistance, change towards patient-specific solutions and establishing digital workflows for adequate quality control during all phases of treatment, i.e. pre-, intra- and postoperative. With this paper, this evolutionary process shall be demonstrated as well as display the spirit of change that was necessary to optimize reconstructive orbital surgery and to improve medical care in all areas of reconstruction. Finally, reconstructive orbital surgery could prove to be a highly foreseeable field nowadays, thus giving the next generation of CMF-surgeons a huge opportunity to drive this topic further into the future.