Navigation-Guided Reduction and Orbital Floor Reconstruction in the Treatment of Zygomatic-Orbital-Maxillary Complex Fractures

Three-dimensional computer navigation in the reconstruction of complex unilateral orbital fractures: evaluation and review of applications

BACKGROUND

The eyes are the central aesthetic unit of the face. Maxillofacial trauma can alter facial proportions and affect visual function with varying degrees of severity. Conventional approaches to reconstruction have numerous limitations, making the process challenging. The primary objective of this study was to evaluate the application of three-dimensional (3D) navigation in complex unilateral orbital reconstruction.

METHODS

A prospective cohort study was conducted over 19 months (January 2020 to July 2021), with consecutive enrollment of 12 patients who met the inclusion criteria. Each patient was followed for a minimum period of 6 months. The principal investigator carried out a comparative analysis of several factors, including fracture morphology, orbital volume, globe projection, diplopia, facial morphic changes, lid retraction, and infraorbital nerve hypoesthesia.

RESULTS

Nine patients had impure orbital fractures, while the remainder had pure fractures. The median orbital volume on the normal side (30.12 cm3; interquartile range [IQR], 28.45-30.64) was comparable to that of the reconstructed orbit (29.67 cm3; IQR, 27.92-31.52). Diplopia improved significantly (T(10) = 2.667, p = 0.02), although there was no statistically significant improvement in globe projection. Gross symmetry of facial landmarks was achieved, with comparable facial width-to-height ratio and palpebral fissure lengths. Two patients reported infraorbital hypoesthesia at presentation, which persisted at the 6-month follow-up. Additionally, five patients developed lower lid retraction (1-2 mm), and one experienced implant impingement at the infraorbital border.

CONCLUSION

Our study provides level II evidence supporting the use of 3D navigation to improve surgical outcomes in complex orbital reconstruction.

Accuracy of surgical navigation for patient-specific reconstructions of orbital fractures: A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to review the recent literature on the technical accuracy of surgical navigation for patient-specific reconstruction of orbital fractures using a patient-specific implant, and to compare surgical navigation with conventional techniques.

MATERIALS AND METHODS

A systematic literature search was conducted in PubMed (Medline), Embase, Web of Science, and Cochrane (Core Collection) databases on May 16, 2023. Literature comparing surgical navigation with a conventional method using postoperative three-dimensional computed tomography imaging was collected. Only articles that studied at least one of the following outcomes were included: technical accuracy (angular accuracy, linear accuracy, volumetric accuracy, and degree of enophthalmos), preoperative and perioperative times, need for revision, complications, and total cost of the intervention. MINORS criteria were used to evaluate the quality of the articles.

RESULTS

After screening 3733 articles, 696 patients from 27 studies were included. A meta-analysis was conducted to evaluate volumetric accuracy and revision rates. Meta-analysis proved a significant better volumetric accuracy (0.93 cm3 ± 0.47 cm3) when surgical navigation was used compared with conventional surgery (2.17 cm3 ± 1.35 cm3). No meta-analysis of linear accuracy, angular accuracy, or enophthalmos was possible due to methodological heterogeneity. Surgical navigation had a revision rate of 4.9%, which was significantly lower than that of the conventional surgery (17%). Costs were increased when surgical navigation was used.

CONCLUSION

Studies with higher MINORS scores demonstrated enhanced volumetric precision compared with traditional approaches. Surgical navigation has proven effective in reducing revision rates compared to conventional approaches, despite increased costs.

Insights into orbital morphological features and fracture patterns in medial and inferior wall fracture: a retrospective cohort study

This study investigated the orbital morphological features that lead to fractures at different sites by comparing patients with isolated inferior wall fracture (IWF) to patients with isolated medial wall fracture (MWF). This study analyzed the orbital morphologic characteristics of all orbital fracture patients who underwent orbital computed tomography (CT) scans between January 2017 and October 2022. On CT scans, the bony structures of the orbit were measured. We investigated the bilateral symmetry of orbital. In addition, orbital morphological differences were compared between patients with fractures of the medial wall and those with fractures of the inferior wall. A total of 135 patients with orbital fractures were included in the study. Of these, 91 were isolated MWFs and 44 were isolated IWF. We confirmed the symmetry of bilateral orbits and measured the orbit of the uninjured side. No differences were found between the MWF group and the IWF group in terms of ocular prominence, horizontal orbital diameter, orbital rim angle, sagittal orbital depth, sagittal orbital depth, and angle of inferior wall inclination. The distance between the infraorbital nerve (ION) entry point and the orbital rim was significantly smaller in the inferior lateral wall fracture group than in the MWF group (11.87 ± 2.54 vs 14.90 ± 4.64, P < 0.001), and the percentage of type 1 ION was significantly lower in the IWF group than in the MWF group (40.9% vs 65.9%, P = 0.012). We demonstrated the symmetry of bilateral orbits and found that when the point where the ION enters the infraorbital canal is near the orbital rim, patients are more prone to suffering a fracture of the inferior wall after orbital trauma. It is less likely for patients with type 1 ION to suffer an IWF following an orbital fracture.

Revisiting bilateral bony orbital volumes comparison using 3D reconstruction in Korean adults: a reference study for orbital wall reconstruction, 3D printing, and navigation by mirroring

BACKGROUND

Orbital wall fractures can result in changes to the bony orbital volume and soft tissue. Restoring the bony orbital and intraconal fat volumes is crucial to prevent posttraumatic enophthalmos and hypoglobus. We aimed to establish an evidence-based medical reference point for "mirroring" in orbital wall reconstruction, which incorporates three-dimensional (3D)-printing and navigation-assisted surgery, by comparing bilateral bony orbital volumes.

METHODS

We retrospectively analyzed the data obtained from 100 Korean adults who did not have orbital wall fractures, categorized by age groups. The AVIEW Research software (Coreline Soft Inc., Seoul, South Korea) was used to generate 3D reformations of the bony orbital cavity, and bony orbital volumes were automatically calculated after selecting the region of interest on consecutive computed tomography slices.

RESULTS

The mean left and right orbital volume of males in their 20 s was 24.67 ± 2.58 mL and 24.70 ± 2.59 mL, respectively, with no significant difference in size (p = 0.98) and Pearson's correlation coefficient of 0.977 (p < 0.001). No significant differences were found in orbital volumes in other age groups without fractures or in patients with nasal bone fractures (p = 0.84, Pearson's correlation coefficient 0.970, p < 0.001). The interclass correlation coefficients (2,1) for inter- and intrarater reliability were 0.97 (p < 0.001) and 0.99 (p < 0.001), respectively.

CONCLUSIONS

No significant differences were found in the bilateral bony orbital volumes among males of any age. Thus, the uninjured orbit can be used as a volumetric reference point for the contralateral injured orbit during orbital wall reconstruction.

The role of intraoperative navigation in surgical treatment of unilateral zygomatic complex fractures: A systematic review and meta-analysis

PURPOSE

The application of a computer-aided navigation system (CANS) in zygomatic complex (ZMC) fractures has been extensively reported, but individual results are heterogeneous. The purpose of this systematic review was to evaluate the role of CANS in the surgical treatment of unilateral ZMC fractures.

METHODS

Electronic retrieval of MEDLINE, Embase, and Cochrane Library (CENTRAL) and manual searching until November 1, 2022 were used to identify cohort studies and randomized controlled trials employing CANS in the surgical treatment of ZMC fractures. The identified reports contained at least 1 of the following outcome variables: accuracy of reduction, total treatment time, amount of bleeding, postoperative complications, satisfaction, and cost. Weighted or mean differences (MD), risk ratios, and corresponding 95% confidence intervals (CI) were calculated, where P＜.05 and I²＞50% random-effect model was adopted, and a vice versa fixed-effect model was adopted. Descriptive analysis was applied to qualitative statistics. The protocol was conducted in accordance with PRISMA guidelines and prospectively registered with PROSPERO (CRD42022373135).

RESULTS

A total of 562 studies were identified, of which 2 cohort studies and 3 randomized controlled trials with 189 participants were included. Meta-analysis indicated that employing CANS significantly decreased the reduction error (MD = -0.86, 95% CI -1.58 to -0.14; P = .02, random-effect model) compared with conventional surgery without using CANS. The differences in total treatment time (preoperative planning time: MD = 1.44, 95% CI -3.55 to 6.43; P = .57 and operative time: MD = 3.02, 95% CI -9.21 to 15.26; P = .63, fixed-effect model) and amount of bleeding (MD = 14.86, 95% CI -8.86 to 38.58; P = .22, fixed-effect model) were not statistically significant between the two groups. Descriptive analysis suggested that postoperative complications, postoperative satisfaction, and cost were also similar with or without CANS.

CONCLUSION

Within the limitations of the present review, the reduction accuracy of unilateral ZMC fractures using CANS is superior to that of conventional surgery. CANS presents limited influence on operation time, amount of bleeding, postoperative complications, postoperative satisfaction, and cost.

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.

Accuracy of virtual planning and intraoperative navigation in zygomaticomaxillary complex fractures: A systematic review

OBJECTIVE

This systematic review aims to investigate the effect of virtual planning on the treatment of zygomaticomaxillary complex (ZMC) traumatology followed by intraoperative navigation. Furthermore, clinical outcomes following intraoperative navigation surgery or conventional surgery will be compared.

MATERIALS AND METHODS

A systematic literature search was conducted in PubMed, Embase, Web-of-Science, and Cochrane on January 1st, 2022. Inclusion criteria were articles using preoperative three-dimensional (3D) virtual planning combined with intraoperative navigation or comparing these 3D methods with conventional methods. Furthermore, at least one of the following outcomes needed to be included in the article: technical accuracy of the procedure, preoperative planning time, operative time, number of fixation points, patient satisfaction, complications, or total costs of the intervention.

RESULTS

Following the screening of 4478 articles, 17 were included. Five articles appeared to indicate a significantly better technical linear accuracy, one article reported better accuracy for rotation and two articles showed better accuracy in restoring orbital volume when using navigation. Nine articles investigated operative time with varying results. Seven articles calculated the additional costs, of which three concluded no extra cost while the others indicated high additional costs or questionable cost-effectiveness.

CONCLUSION

Virtual planning and intraoperative navigation technologies have the potential to assist maxillofacial trauma surgeons in reducing ZMC fractures significantly more accurately and restoring the facial contour in a less invasive manner at an acceptable cost.

REGISTRATION

The protocol for this systematic review (CRD42020216717) was registered in the International Prospective Register of Systematic Reviews (PROSPERO).

Application of Computer-Aided Design and Individualized Templates for Bilateral Zygomaticomaxillary Complex Fractures

PURPOSE

Reduction of the bilateral zygomaticomaxillary complex (ZMC) fracture with individualized templates based on computer- aided surgical simulation system. To evaluate the practicality and accuracy of this approach in the treatment of bilateral ZMC fracture.

METHODS

Sixteen patients with bilateral ZMC fractures were collected to create a study model. The authors reconstruct the ZMC on one side via the three-dimensional (3D) model, and then mirrored to the opposite side. Multiple individualized templates were made based on the 3D model, and used as intraoperative guidance to reduce fractures. After surgery, the facial symmetry and the position of zygoma were observed. The mouth opening, pupil level, and sensation of infraorbital nerve were evaluated. Some mark points on zygoma were measured and the postoperative horizontal asymmetry rate (H) was calculated. Besides, orbital height and width were measured.

RESULTS

For all patients, the position of bilateral ZMC was basically restored. The patients with restriction of mouth opening all recovered to normal. The H values were less than 3.0% at all mark points. There was almost no difference in bilateral orbital width and height. Meanwhile, there was no significant difference between the preoperative measurements of the ideal virtual 3D model and the postoperative measurements of patients.

CONCLUSIONS

The study proves that application of computer-aided design and individualized templates can accurately guide the reduction operation of ZMC fracture, restore the ideal shape of ZMC, and obtain good facial symmetry.

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.

Reduction of giant parietooccipital fibrous dysplasia using dynamic mirror image guidance: a case report and review of the literature

BACKGROUND

Craniofacial fibrous dysplasia (CFD) typically occurs in the facial bones and anterior cranial vault and can produce both disfigurement and functional limitations for patients disfigurement. Treatment consists of reducing the abnormal bone. Bone contouring can become challenging when the exposure does not extend to the corresponding normal contralateral structures for comparison or when normal landmarks are not available, which may compromise the overall aesthetic outcome. We describe a technique using dynamic mirroring to accurately contour the involved part of the cranium in a case of giant CFD.

OBSERVATIONS

A 49-year-old male presented with a giant deforming fibrous dysplasia of the right mastoid and parieto-temporo-occiput that was causing functional limitations due to the size of the bony mass. This was managed with multidisciplinary bony reduction. Several neurovascular structures were in proximity to the areas of planned drilling of the expansile lesion, and dynamic mirroring of the uninvolved left skull was utilized to maximize safety and symmetry of reduction. High-speed drilling of the right occipital bone was performed until the navigation system alerted the surgeon that symmetric depth had been achieved. There were no complications from the procedure and this technique maximized the limits of symmetric reduction without significantly increasing surgical complexity or duration.

LESSONS

Dynamic mirroring of bony structures in the posterior cranium is not commonly employed in neurosurgical practice. This technique may help improve the aesthetic outcomes of bony reduction in craniofacial dysplasia and a variety of similarly managed bony lesions, contour cranioplasties, and in unilateral craniosynostosis surgery.

Surgical Navigation in Mandibular Reconstruction: Accuracy Evaluation of an Innovative Protocol

Aim: the purpose of this work is to present an innovative protocol for virtual planning and surgical navigation in post-oncological mandibular reconstruction through fibula free flap. In order to analyze its applicability, an evaluation of accuracy for the surgical protocol has been performed. Methods: 21 patients surgically treated for mandibular neoplasm have been included in the analysis. The Brainlab Vector Vision 3.0^® software for surgical navigation has been used for preoperative surgical planning and intra-operative navigation. A post-operative accuracy evaluation has been performed matching the position of mandibular landmarks between pre-operative and post-operative CT scans. Results: the maximal discrepancy observed was included between −3.4 mm and +3.2 mm, assuming negative values for under correction and positive values for overcorrection. An average grade of accuracy included between 0.06 ± 0.58 mm and 0.43 ± 0.68 mm has been observed for every mandibular landmark examined, except for mandibular angles that showed a mean discrepancy value included between 1.36 ± 1.73 mm and 1.46 ± 1.02 mm when compared to preoperative measurements. Conclusion: a satisfying level of accuracy has been observed in the protocol presented, which appears to be more versatile if compared to closed custom-made systems. The technique described may represent a valid option for selected patients, but it cannot be considered for routine activity because of the complexity of the method, the mobility of the jaw, the necessity of surgical navigator and the long surgical learning curve that is required.

Digital planning and individual implants for secondary reconstruction of midfacial deformities: A pilot study

Objective

To evaluate the feasibility and accuracy of implementing three‐dimensional virtual surgical planning (VSP) and subsequent transfer by additive manufactured tools in the secondary reconstruction of residual post‐traumatic deformities in the midface.

Methods

Patients after secondary reconstruction of post‐traumatic midfacial deformities were included in this case series. The metrical deviation between the virtually planned and postoperative position of patient‐specific implants (PSI) and bone segments was measured at corresponding reference points. Further information collected included demographic data, post‐traumatic symptoms, and type of transfer tools.

Results

Eight consecutive patients were enrolled in the study. In five patients, VSP with subsequent manufacturing of combined predrilling/osteotomy guides and PSI was performed. In three patients, osteotomy guides, repositioning guides, and individually prebent plates were used following VSP. The median distances between the virtually planned and the postoperative position of the PSI were 2.01 mm (n = 18) compared to a median distance concerning the bone segments of 3.05 mm (n = 12). In patients where PSI were used, the median displacement of the bone segments was lower (n = 7, median 2.77 mm) than in the group with prebent plates (n = 5, 3.28 mm).

Conclusion

This study demonstrated the feasibility of VSP and transfer by additive manufactured tools for the secondary reconstruction of complex residual post‐traumatic deformities in the midface. However, the median deviations observed in this case series were unexpectedly high. The use of navigational systems may further improve the level of accuracy.

To evaluate the feasibility and accuracy of implementing three‐dimensional virtual surgical planning (VSP) and subsequent transfer by additive manufactured tools in the secondary reconstruction of residual post‐traumatic deformities in the midface. This study demonstrated the feasibility of VSP and transfer by additive manufactured tools for the secondary reconstruction of complex residual post‐traumatic deformities in the midface. However, the median deviations observed in this case series were unexpectedly high. The use of navigational systems may further improve the level of accuracy.

Efficacy of surgical navigation in zygomaticomaxillary complex fractures: randomized controlled trial

Accurate reduction is of vital importance in the treatment of zygomaticomaxillary complex (ZMC) fractures. Computer-assisted navigation systems (CANS) have been employed in ZMC fractures to improve the accuracy of surgical reduction. However, randomized controlled trials on this subject are rare and the benefits of CANS remain controversial. The aim of this study was to compare reduction errors between navigation-aided and conventional surgical treatment for ZMC fractures. Thirty-eight patients with unilateral type B ZMC fractures were enrolled. Preoperative computed tomography data were imported into ProPlan software for virtual surgical planning. Open reduction and internal fixation was performed with CANS (experimental group) or without CANS (control group). Postoperative computed tomography scans were obtained to examine the difference between surgical planning and the actual postoperative outcome, namely reduction errors. The median translational reduction errors in the X, Y, and Z axes were 0.80 mm, 0.40 mm, and 0.80 mm, respectively, in the experimental group and 0.53 mm, 0.86 mm, and 0.83 mm, respectively, in the control group (P > 0.05). The median rotational reduction errors in pitch, roll, and yaw were 0.92°, 2.47°, and 1.54°, respectively, in the experimental group and 1.45°, 3.68°, and 0.76°, respectively, in the control group (P > 0.05). In conclusion, compared with conventional reduction surgery, navigation-aided surgery showed no significant improvement in reduction accuracy in the treatment of type B ZMC fractures (Chinese Clinical Trial Registry, registration number ChiCTR1800015559).

Zygomaticomaxillary Fractures

Fractures of the zygomaticomaxillary complex and zygomatic arch are common athletic injuries. Fracture displacement can lead to midfacial retrusion and widening, causing noticeable deformity. Associated signs and symptoms include hypoesthesia of the infraorbital nerve distribution, trismus, and subjective malocclusion. Operative treatment is indicated in cases of significant displacement or functional disturbance. The approach and details of osteosynthesis are catered to the specific characteristics of the fracture. Technology, such as virtual surgical planning, intraoperative navigation, and intraoperative imaging, has the potential to improve accuracy of treating challenging fractures.

A Three-dimensionally Printed Acrylonitrile Butadiene Styrene Model for the Reduction of Nasomaxillary Fracture

The successful reduction of a nasomaxillary fracture was performed using a three-dimensional printed model. A 16-year-old boy was struck in the left orbit by a baseball; subsequently, he was diagnosed with the nasal bone fracture at a hospital, and was referred to the authors' department. A left nasomaxillary fracture and nasal bone fracture were diagnosed by computed tomography. Standard triangulated language data for the mirror image of the frontal process of the right maxilla were obtained from digital imaging and communications in medicine data for preparing a three-dimensional printed acrylonitrile butadiene styrene model. On postinjury day 13, the frontal process fracture was reduced via transconjunctival and intraoral approaches. After the reduction of the fracture, an absorbable plate fitting to the shape of three-dimensional printed acrylonitrile butadiene styrene model was molded, and the maxillary frontal process and infraorbital rim were reduced and fixed with an absorbable plate and screws. Postoperative computed tomography demonstrated a favorable reduction. The intraoperative use of the 3D printed acrylonitrile butadiene styrene model was helpful in the nasomaxillary fracture reduction and fixation.

Management of Traumatic Trigeminal and Facial Nerve Injuries

In the area of craniomaxillofacial trauma, neurosensory disturbances are encountered commonly, especially with regard to the trigeminal and facial nerve systems. This article reviews the specific microanatomy of both cranial nerves V and VII, and evaluates contemporary neurosensory testing, current imaging modalities, and available nerve injury classification systems. In addition, the article proposes treatment paradigms for management of trigeminal and facial nerve injuries, specifically with regard to the craniomaxillofacial trauma setting.

Augmented reality navigation method for recontouring surgery of craniofacial fibrous dysplasia

The objective of this study is to introduce the application of augmented reality (AR) navigation system developed by the authors in recontouring surgery of craniofacial fibrous dysplasia. Five consecutive patients with craniofacial fibrous dysplasia were enrolled. Through three-dimensional (3D) simulation, a virtual plan was designed to reconstruct the normal anatomical contour of the deformed region. Surgical recontouring was achieved with the assistance of the AR navigation system. The accuracy of the surgical procedure was assessed by superimposing the post-operative 3D craniomaxillofacial model onto the virtual plan. The pre-operative preparation time and operation time were also counted. In all patients, AR navigation was performed successfully, with a mean ± SD of the errors of 1.442 ± 0.234 mm. The operative time of the patients ranged from 60 to 80 min. The pre-operative preparation time was 20 min for each patient. All the patients showed uneventful healing without any complications, in addition to satisfaction with the post-operative aesthetics. Using our AR navigation system in recontouring surgery can provide surgeons with a comprehensive and intuitive view of the recontouring border, as well as the depth, in real time. This method could improve the efficiency and safety of craniofacial fibrous dysplasia recontouring procedures.

Role of Navigation in Oral and Maxillofacial Surgery: A Surgeon's Perspectives

Surgeries related to the maxillofacial area deal with an intricate network of anatomical structures. With the complexity of the vital structures, it necessitates a surgical team to respect each anatomical boundary. In the past, there was an exceptionally high number of cases with surgical errors. These errors were not because of flaws in the surgeon’s skills or techniques but owing to lack of resources. Visualisation is one of the key factors that determines the precision of any surgical outcome. Advances in surgical planning have led to the introduction of a “Navigation” system that helps surgeons to see more, know more and ultimately do more for their patients. The usefulness of the navigation system in oral surgeries has been indicated by its surgical applications in craniomaxillofacial trauma, orthognathic surgeries, head and neck pathological resections, complex skull base surgeries and surgery involving temporomandibular joint. A vast majority of research literature has suggested remarkable improvement in surgical outcomes under the guidance of 3d planning and navigation. However, with such an inordinate advancement, financial expenses and a gradual learning curve are always a constraining factor in surgical navigation. This article overviews indication of navigation in craniofacial surgeries with a focus on applied aspect, planning and solution to the future problem.

Use of augmented reality navigation to optimise the surgical management of craniofacial fibrous dysplasia

The aim of this study was to apply an augmented reality (AR) navigation technique based on a head- mounted display in the treatment of craniofacial fibrous dysplasia and to explore the feasibility and the value of AR in craniofacial surgery. With preoperative planning and three-dimensional simulation, the normal anatomical contours of the deformed area were recreated by superimposing the unaffected side on to the affected side. We completed the recontouring procedures in real time with the aid of an AR navigation system. The surgical outcome was assessed by superimposing the postoperative computed tomographic images on to the preoperative virtual plan. The preparation and operation times were recorded. With intraoperative AR guidance, facial bone recontouring was performed uneventfully in all cases. The mean (SD) discrepancy between the actual surgical reduction and preoperative planning was 1.036 (0.081) mm (range: 0.913 (0.496) to 1.165 (0.498) mm). The operation time ranged from 50 to 80 minutes, with an average of 66.4 minutes. The preoperative preparation time ranged from 26 to 36 minutes, with a mean of 29.6 minutes. AR navigation-assisted facial bone recontouring is a valuable treatment modality in managing craniomaxillofacial fibrous dysplasia and shows benefits in improving the efficiency and safety of this complicated procedure.

Secondary Reconstruction of the Zygomaticomaxillary Complex

Zygomaticomaxillary (ZMC) fractures are the second most common facial fractures after nasal bone fractures. The zygoma, with its location and multiple points of articulations, lends itself to both facial structure and esthetics. Secondary ZMC deformities are complications of inadequate primary correction, delayed repair, or lack of repair. Secondary revisions of ZMC aim to correct ZMC displacement and projection and to address orbital discrepancies. Extensive correction involving significant orbital and malar defects requires zygomatic repositioning osteotomies and would greatly benefit from the utilization of virtual surgical planning, intraoperative navigation, and imaging. Minor corrections in malar projection can be corrected by onlay grafting and soft tissue augmentation and resuspension. Isolated or minor orbital corrections can be managed by autogenous or alloplastic material to restore lost orbital volume and anatomy.

A Splint-to-CT Data Registration Strategy for Maxillary Navigation Surgery

Computer-assisted navigation plays an important role in modern craniomaxillofacial surgery. Although headpins and skull posts are widely used for the fixation of the reference frame, they require the use of invasive procedures. Headbands are easily displaced intraoperatively, thus reducing the accuracy of the surgical outcome. This study reported the utility of a novel splint integrated with a reference frame and registration markers for maxillary navigation surgery. A maxillary splint with a 10 cm resin handle was fabricated before surgery, to fix the reference frame to the splint. The splint was set after the incorporation of fiducial gutta-percha markers into both the splint and resin handle for marker-based pair-point registration. A computed tomography (CT) scan was acquired for preoperative CT-based planning. A marker-based pair-point registration procedure can be completed easily and noninvasively using this custom-made integrated splint, and maxillary navigation surgery can be performed with high accuracy. This method also provides maximum convenience for the surgeon, as the splint does not require reregistration, and can be removed temporarily when required. The splint-to-CT data registration strategy has potential applicability not only for maxillary surgery but also for otolaryngologic surgery, neurosurgery, and surgical repair after craniofacial trauma.

Does Intraoperative Computed Tomography Improve the Outcome in Zygomatico-Orbital Complex Fracture Reduction?

Purpose

Zygomatico-orbital (ZMO) fractures pose considerable difficulty in intraoperative assessment during open reduction and internal fixation (ORIF), and this can be attributed to its three-dimensional complex anatomy and articulations. Recent advancements in the form of intraoperative imaging and navigation have led to an adequate assessment and correct reduction of these fractures minimizing chances of any revision surgery. The purpose of this study was to evaluate the advantage of intraoperative computerized tomography (CT) scan in the management of ZMO/isolated orbital complex fracture and further to develop a protocol for managing such fractures.

Methods

Twenty-three cases of ZMO/isolated orbital fractures were managed with ORIF, followed by an intraoperative CT scan. The evaluation was focused on the articulations of the zygoma and orbital wall reconstruction. The score of 0 and 1 was given for inadequate and adequate reduction, respectively. Necessary corrections were performed in case of improper reduction followed by a repeat CT scan if required. The reduction score was statistically correlated with number of incisions.

Results

In 8 (35%) out of 23 patients, clinical judgment was inaccurate when radiologically assessed with an intraoperative CT scan. In 6 out of 8 cases, a repeat CT scan was done after revision of reduction. The reduction score improved with additional incision and revision in the second CT scan.

Conclusion

Intraoperative CT has an important role in assessing the accuracy of reduction and confirming implant position in ZMO/isolated orbital fractures. This can avoid the need for secondary corrective surgery and postoperative imaging. Intraoperative CT is an important tool to improve surgical outcomes in the management of ZMO orbital fractures.

[Use of navigation in skull base surgery]

The review briefly presents the history of development of navigation systems in neurosurgery. The idea of the existing principles underlying the navigation systems used in neurosurgery is given. Currently, the basic principles of navigation are optical and electromagnetic. Studies are presented comparing the accuracy of various navigation systems. Optical navigation demonstrates greater accuracy compared to electromagnetic, but both methods demonstrate a submillimeter error in the experiment. The history of use of navigation in the surgery of the skull base is analyzed in detail, the most relevant areas of use of navigation within the surgery of the skull base are considered: craniofacial reconstruction, endoscopic endonasal surgery, surgery of common tumors of the skull base affecting the infratemporal, pterygopalatine fossa, temporomandibular joint. Indications for the use of navigation, limitations of the methodology are explained.

Application of Computer-Aided Navigation Technology in the Extraction of Foreign Body From the Face

In the oral and maxillofacial foreign body (FB) extraction surgery, computer-aided navigation technical surgery is minimally invasive and safe, and can improve the accuracy, especially for areas with relatively complex and dangerous anatomical structures. A total of 11 patients, including 8 males and 3 females, who underwent the extraction surgery of FB from oral and maxillofacial regions using computer-aided navigation technical surgery were reviewed. According to the positional relationship between the maxillofacial region and the bone tissue, the FBs were divided into 3 categories: FB in the bone; FB aside the bone; and soft-tissue FB. During the operation, the BrainLab Navigation system was used to observe and guide the operation in real-time to evaluate the effectiveness and accuracy of computer-aided navigation technical surgery in the extraction of FBs from the maxillofacial regions. The FBs were successfully located and removed in 11 patients. No adjacent nerves, blood vessels, and other important anatomical structures were injured during the operation. The postoperative function and shape were not significantly affected.

Facial Transplantation for an Irreparable Central and Lower Face Injury: A Modernized Approach to a Classic Challenge

BACKGROUND

Facial transplantation introduced a paradigm shift in the reconstruction of extensive facial defects. Although the feasibility of the procedure is well established, new challenges face the field in its second decade.

METHODS

The authors' team has successfully treated patients with extensive thermal and ballistic facial injuries with allotransplantation. The authors further validate facial transplantation as a reconstructive solution for irreparable facial injuries. Following informed consent and institutional review board approval, a partial face and double jaw transplantation was performed in a 25-year-old man who sustained ballistic facial trauma. Extensive team preparations, thorough patient evaluation, preoperative diagnostic imaging, three-dimensional printing technology, intraoperative surgical navigation, and the use of dual induction immunosuppression contributed to the success of the procedure.

RESULTS

The procedure was performed on January 5 and 6, 2018, and lasted nearly 25 hours. The patient underwent hyoid and genioglossus advancement for floor-of-mouth dehiscence, and palate wound dehiscence repair on postoperative day 11. Open reduction and internal fixation of left mandibular nonunion were performed on postoperative day 108. Nearly 1 year postoperatively, the patient demonstrates excellent aesthetic outcomes, intelligible speech, and is tolerating an oral diet. He remains free from acute rejection.

CONCLUSIONS

The authors validate facial transplantation as the modern answer to the classic reconstructive challenge imposed by extensive facial defects resulting from ballistic injury. Relying on a multidisciplinary collaborative approach, coupled with innovative emerging technologies and immunosuppression protocols, can overcome significant challenges in facial transplantation and reinforce its position as the highest rung on the reconstructive ladder.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Computer-assisted navigation in orbitofacial surgery

The purpose of this systematic review is to investigate the most common indications, treatment, and outcomes of computer-assisted surgery (CAS) in ophthalmological practice. CAS has evolved over the years from a neurosurgical tool to maxillofacial as well as an instrument to orbitofacial surgeries. A detailed and organized scrutiny in relevant electronic databases, journals, and bibliographies of the cited articles was carried out. Clinical studies with a minimum of two study cases were included. Navigation surgery, posttraumatic orbital reconstruction, computer-assisted orbital surgery, image-guided orbital decompression, and optic canal decompression (OCD) were the areas of interest. The search generated 42 articles describing the use of navigation in facial surgery: 22 on orbital reconstructions, 5 related to lacrimal sac surgery, 4 on orbital decompression, 2 articles each on intraorbital foreign body and intraorbital tumors, 2 on faciomaxillary surgeries, 3 on cranial surgery, and 2 articles on navigation-guided OCD in traumatic optic neuropathy. In general, CAS is reported to be a useful tool for surgical planning, execution, evaluation, and research. The largest numbers of studies and patients were related to trauma. Treatment of complex orbital fractures was greatly improved by the use of CAS compared with empirically treated control groups. CAS seems to add a favourable potential to the surgical armamentarium. Planning details of the surgical approach in a three-dimensional virtual environment and execution with real-time guidance can help in considerable enhancement of precision. Financial investments and steep learning curve are the main hindrances to its popularity.

Surgical navigation improves reductions accuracy of unilateral complicated zygomaticomaxillary complex fractures: a randomized controlled trial

Accurate reduction is the key to successful treatment of bone fractures. Complicated zygomaticomaxillary complex fracture, known as one of the most challenging facial bone fractures, is often hard to achieve an accurate reduction, thus leading to facial deformity. In this study, twenty patients with unilateral complicated zygomaticomaxillary complex fractures were included and randomly divided into experimental and control groups, which is with and without the aid of surgical navigation, respectively. The pre- and postoperative imaging data were collected and then analysed using Geomagic Studio 11 software and Brainlab iPlan CMF 3.0. A more precise reduction was showed in the experimental group according to the measurement results of both software programmes than in the control group. In conclusion, surgical navigation showed great value in performing accurate reductions of complicated zygomaticomaxillary complex fractures and restoring facial contour.

Development of a novel anatomical thin titanium mesh plate with reduction guidance and fixation function for Asian zygomatic-orbitomaxillary complex fracture

For this study we developed an anatomical thin titanium mesh (ATTM) plate for Asian zygomaticomaxillary complex (ZMC) fracture repair with reduction guidance and fixation function. The ATTM plate profile was designed as an L-shape to fix at the anterior maxilla and lateral buttress of the ZMC. Computer-aided stamping analysis was performed on four screw-hole patterns in the ATTM plate - a control without screw-holes, square screw-holes, double screw-holes, and large-diameter, double screw-holes - using upper/lower dies of averaged ZMC reconstruction models. A regular ATTM plate of 0.6 mm thickness was manufactured and pre-bent using a patient-matched stamping process to verify its feasibility on three ZMC fracture models with one, two, and three fracture segments. The stamping analysis found that the double screw-holes design resulted in the most favorable performance among all the designs because of maximum von Mises stress (408 MPa) under the ultimate tensile strength. Positioning practice showed that the stamped, pre-bent ATTM plate can be used as a reduction guide to provide precise ZMC segment fixation in a completely passive fashion while limiting redundant rotation/micromovement between the separate bones in all directions. This study concluded that the ATTM plate with double screw-hole pattern design, using a patient-matched, pre-bent technique, can fit the ATTM plate/ZMC interface well, decrease mobility of unstable fracture segments, and provide good original facial contour recovery, while improving reduction efficiency.

Zygomaticomaxillary complex fractures: diagnosis and treatment

PURPOSE OF REVIEW

To provide an overview of zygomaticomaxillary complex (ZMC) fractures and their treatment. Aspects of anatomy, diagnosis, and treatment objectives of these common fractures will be reviewed including recent literature.

RECENT FINDINGS

Advances in technology such as guided surgery have allowed for better outcomes and a reduction in surgeon variability with regard to postoperative results. The use of titanium and bioresorbable mini screws and plates have expanded the ability to achieve stable and predictable results. There are many different challenges and techniques that are acceptable to treat zygoma fractures. Surgeon preference and training dictate these methods that vary among specialties.

SUMMARY

ZMC fractures are commonly encountered in the trauma setting. Although there is a multitude of treatment methods available, the ultimate goal for any surgeon should be to reproduce premorbid form and function. The availability of techniques such as 3D navigation, contralateral mirroring, and advances in fixation technology have shown promise for better outcomes, particularly in severely comminuted or displaced fractures.

Surgical Navigation: A Systematic Review of Indications, Treatments, and Outcomes in Oral and Maxillofacial Surgery

PURPOSE

This systematic review investigates the most common indications, treatments, and outcomes of surgical navigation (SN) published from 2010 to 2015. The evolution of SN and its application in oral and maxillofacial surgery have rapidly developed over recent years, and therapeutic indications are discussed.

MATERIALS AND METHODS

A systematic search in relevant electronic databases, journals, and bibliographies of the included articles was carried out. Clinical studies with 5 or more patients published between 2010 and 2015 were included. Traumatology, orthognathic surgery, cancer and reconstruction surgery, skull-base surgery, and foreign body removal were the areas of interests.

RESULTS

The search generated 13 articles dealing with traumatology; 5, 6, 2, and 0 studies were found that dealt with the topics of orthognathic surgery, cancer and reconstruction surgery, skull-base surgery, and foreign body removal, respectively. The average technical system accuracy and intraoperative precision reported were less than 1 mm and 1 to 2 mm, respectively. In general, SN is reported to be a useful tool for surgical planning, execution, evaluation, and research. The largest numbers of studies and patients were identified in the field of traumatology. Treatment of complex orbital fractures was considerably improved by the use of SN compared with traditionally treated control groups.

CONCLUSIONS

SN seems to be a very promising addition to the surgical toolkit. Planning details of the surgical procedure in a 3-dimensional virtual environment and execution with real-time guidance can significantly improve precision. Among factors to be considered are the financial investments necessary and the learning curve.

Navigation-Assisted Bone Grafting for Blowout Fracture

BACKGROUND

Treatment of orbital floor fracture accompanied by extensive bone defect requires orbital floor reconstruction using a bone graft, but graft may deviate into the maxillary sinus when no bone capable of supporting the graft remains around the defect. In such cases, it is necessary to fix the grafted bone to the orbital margin, but the grafted bone placement site is subjectively decided based on inspection through a small incision in many cases, being dependent on the experience of operators, and it has been difficult to accurately determine the placement angle.

METHODS

The authors applied a navigation system in 4 patients with orbital blowout fracture, and evaluated for the exact bone graft placement angle and orbital floor form during surgery.

RESULTS

The bone graft placement angle was evaluated by comparison with a mirror image of the nonaffected side. The angle could be confirmed during surgery, as well as the lateral symmetry of the orbital form. On postoperative computed tomography, the grafted bone was retained at a favorable placement site.

CONCLUSIONS

The navigation system may be useful to support the treatment of orbital blowout fracture, as it facilitates safe dissection around orbital floor bone defects, confirmation of the positional relationship between the bone fragment and orbital tissue and bone graft fixation position, and evaluation of lateral symmetry of the orbital floor form during surgery.

Surgical treatment of unilateral zygomaticomaxillary complex fractures: A 7-year observational study assessing treatment outcome in 153 cases

This study investigates treatment outcome in zygomaticomaxillary complex (ZMC) fracture repair.

METHODS

The medical records and CT-images of patients that received treatment for a unilateral ZMC fracture in 2005-2011 were studied. ZMC fractures were categorised as incomplete (type A), tetrapod (type B) or comminuted (type C). The incidence of sequelae, wound infection and secondary surgical interventions was analysed per fracture category.

RESULTS

A total of 153 patients were treated in the selected period. Persisting sensory disturbances in the area innervated by the infraorbital nerve were observed in 50 cases (37%), facial asymmetry in 19 cases (14%), enophthalmos in 10 cases (7%) and persisting diplopia in 9 cases (7%). Wound infection occurred in 6 cases (4%). Secondary surgical procedures of the ZMC, orbital floor, and/or extraocular muscles were performed in 14 cases (9%). C-type fractures were associated with more secondary corrections for ZMC malreduction (12%, p = 0.03), more secondary reconstructions of the orbital floor (10%, p < 0.01), and more functional corrections of diplopia by extraocular muscle correction (5%, p = 0.02).

CONCLUSION

Treatment outcome in C-type ZMC fractures is less favourable than treatment outcome in A-type and B-type fractures. Intraoperative imaging, surgical navigation devices and 3D-planning software may improve treatment outcome in C-type ZMC fractures.

A Novel System for Navigation-and Robot-Assisted Craniofacial Surgery: Establishment of the Principle Prototype

PURPOSE

The authors aimed to develop 1 novel navigation-guided robotic system for craniofacial surgery to improve accuracy during operation.

MATERIALS AND METHODS

A new 7-DOF (7-degree-of-freedom) robotic arm was designed and manufactured. Based on our self-developed navigation system TBNAVIS-CMFS, the key technique of integration was studied. A phantom skull model was manufactured based on computed tomography image data and used for the preexperimental study. Firstly, virtual planning was achieved through the TBNAVIS-CMFS, where the Le Fort I procedure was executed through simulation. Then, the actual Le Fort 1 osteotomy was expected to perform with the use of the robotic arm following the instructions from the navigation system.

RESULTS

The theoretical prototype of navigation-guided robotic system for craniofacial surgery was established successfully, which performed the planned Le Fort I procedure with the whole process visible on the screen.

CONCLUSIONS

The technical method of navigation-guided robotics system, allowing the operator to practice the virtual planning procedure through navigation system as well as perform the actual operation thru the robotic arm, could be regarded as a valuable option for benefiting craniofacial surgeons.

An excellent navigation system and experience in craniomaxillofacial navigation surgery: a double-center study

Numerous problems regarding craniomaxillofacial navigation surgery are not well understood. In this study, we performed a double-center clinical study to quantitatively evaluate the characteristics of our navigation system and experience in craniomaxillofacial navigation surgery. Fifty-six patients with craniomaxillofacial disease were included and randomly divided into experimental (using our AccuNavi-A system) and control (using Strker system) groups to compare the surgical effects. The results revealed that the average pre-operative planning time was 32.32 mins vs 29.74 mins between the experimental and control group, respectively (p > 0.05). The average operative time was 295.61 mins vs 233.56 mins (p > 0.05). The point registration orientation accuracy was 0.83 mm vs 0.92 mm. The maximal average preoperative navigation orientation accuracy was 1.03 mm vs 1.17 mm. The maximal average persistent navigation orientation accuracy was 1.15 mm vs 0.09 mm. The maximal average navigation orientation accuracy after registration recovery was 1.15 mm vs 1.39 mm between the experimental and control group. All patients healed, and their function and profile improved. These findings demonstrate that although surgeons should consider the patients’ time and monetary costs, our qualified navigation surgery system and experience could offer an accurate guide during a variety of craniomaxillofacial surgeries.

Use of Computed Tomography-Derived Prosthetics for Intraoperative Guidance of Tumor Resection

Preoperative computed tomography (CT)-derived design and modeling provides a useful guide for a more accurate reconstruction of a variety of complex maxillofacial deformities. While the use of three-dimensional CT imaging has focused mainly on bony reconstruction, the use of this technique to facilitate soft tissue reconstruction represents an important innovation that can assist surgeons with preoperative planning and intraoperative decision-making. In this study, the authors report the novel use of three-dimensional CT scan modeling to facilitate the resection of a large maxillofacial neurofibroma in a patient with neurofibromatosis. In conjunction with an anaplastologist, the combined use of tangible models and aesthetic judgments significantly optimizes the quality of the initial resection and subsequent reconstruction. By utilizing an interdisciplinary approach, it is possible to achieve optimal symmetry in the setting of complex maxillofacial deformities.