Computer-aided navigation in secondary reconstruction of post-traumatic deformities of the zygoma

Augmented and Virtual Reality Applications in Facial Plastic Surgery: A Scoping Review

OBJECTIVES

Augmented reality (AR) and virtual reality (VR) are emerging technologies with wide potential applications in health care. We performed a scoping review of the current literature on the application of augmented and VR in the field of facial plastic and reconstructive surgery (FPRS).

DATA SOURCES

PubMed and Web of Science.

REVIEW METHODS

According to PRISMA guidelines, PubMed and Web of Science were used to perform a scoping review of literature regarding the utilization of AR and/or VR relevant to FPRS.

RESULTS

Fifty-eight articles spanning 1997-2023 met the criteria for review. Five overarching categories of AR and/or VR applications were identified across the articles: preoperative, intraoperative, training/education, feasibility, and technical. The following clinical areas were identified: burn, craniomaxillofacial surgery (CMF), face transplant, face lift, facial analysis, facial palsy, free flaps, head and neck surgery, injectables, locoregional flaps, mandible reconstruction, mandibuloplasty, microtia, skin cancer, oculoplastic surgery, rhinology, rhinoplasty, and trauma.

CONCLUSION

AR and VR have broad applications in FPRS. AR for surgical navigation may have the most emerging potential in CMF surgery and free flap harvest. VR is useful as distraction analgesia for patients and as an immersive training tool for surgeons. More data on these technologies' direct impact on objective clinical outcomes are still needed.

LEVEL OF EVIDENCE

N/A Laryngoscope, 134:2568-2577, 2024.

Secondary Reconstruction of Late Deformities of the Orbitozygomaticomaxillary Complex using a Halo Device

Reconstructing late deformities of the orbitozygomaticomaxillary complex after inadequate treatment of facial fractures requires zygomatic osteotomy to reposition the bony fragments to their anatomical position. However, confirming the position of the bone fragments can be challenging due to the loss of anatomic landmarks caused by bone remodeling, and swelling resulting from surgery, which might hinder locating the bone from the body surface. Here, the authors describe fixation of the halo of the Blue Device multi-vector distraction system to the patient's ear canal, with alignment of the position of the zygoma by measuring the distances between the halo and zygoma using several reference points. This technique allows for measurement not only from the body surface using a K-wire but also directly to the bone using a needle. The authors applied this technique in 2 cases of post-traumatic deformities after complex zygomatic fractures. Both cases achieved an almost symmetrical appearance of the infraorbital region.

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.

Clinical Application of Augmented Reality in Computerized Skull Base Surgery

Cranial base tactics comprise the regulation of tiny and complicated structures in the domains of otology, rhinology, neurosurgery, and maxillofacial medical procedure. Basic nerves and veins are in the nearness of these buildings. Increased the truth is a coming innovation that may reform the cerebral basis approach by supplying vital physical and navigational facts brought together in a solitary presentation. In any case, the awareness and acknowledgment of prospective results of expanding reality frameworks in the cerebral base region are really poor. This article targets examining the handiness of expanded reality frameworks in cranial foundation medical procedures and emphasizes the obstacles that present innovation encounters and their prospective adjustments. A specialized perspective on distinct strategies used being produced of an improved realty framework is furthermore offered. The newest item offers an expansion in interest in expanded reality frameworks that may motivate more secure and practical procedures. In any case, a couple of concerns have to be cared to before that can be for the vast part fused into normal practice.

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.

Contemporary Management of Zygomaticomaxillary Complex Fractures

Zygomaticomaxillary complex fracture is one of the most commonly treated facial fractures. Accurate reduction and stable fixation of the zygoma are required to restore facial symmetry and projection and avoid functional sequalae from changes in orbital volume. Achieving optimal outcome is challenging due to the complex three-dimensional anatomy and limited visualization of all affected articulations of the zygoma. This article provides an updated overview of the evaluation and management of zygomaticomaxillary complex fractures based on available evidence and clinical experience at our center. The importance of soft tissue management is emphasized, and approaches to internal orbital reconstruction are discussed. While evidence remain limited, intraoperative imaging and navigation may prove to be useful adjuncts in the treatment of zygomaticomaxillary fractures.

Technological Integration of Virtual Surgical Planning, Surgical Navigation, Endoscopic Support and Patient-Specific Implant in Orbital Trauma

Currently, we have different technologies and techniques that improve the results in orbital trauma. However, there are few studies that study the technological integration in orbital trauma and the synergism of all the techniques. For this reason, the objective of this case is to illustrate the management of orbital trauma by integrating endoscopic support, virtual surgical navigation, patient-specific implant, virtual surgical planning in the management of a sequel due to insufficient reconstruction of orbital volume.

Application of real-time surgical navigation for zygomatic fracture reduction and fixation

BACKGROUND

Inappropriate treatment of zygomatic fractures can reduce esthetic and functional outcomes. The aim of this study was to answer the research question: "Among patients with a unilateral zygomatic fracture, is the use of computer-assisted real-time navigation system during fracture reduction precise and accurate to create postoperative facial symmetry?"

METHODS

Using a retrospective cohort study design, we enrolled a cohort of unilateral zygomatic fractures undergoing open reduction and internal fixation (ORIF) with the aid of the computer-based navigation system at Chang Gung Memorial Hospital, Taiwan, during January 2015 and March 2018. The predictor variable was the comparison before and after surgery. The main outcome variables included (1) two-dimensional (2D) reduction of the displacement at five anatomical landmarks: zygomaticofrontal, inferior orbital rim, zygomaticosphenoidal, zygomaticomaxillary, and zygomaticotemporal lines/buttresses and (2) three-dimensional (3D) differences on distances between zygomatic surface to the porion plane and the midpoint of zygomatic arch (ZA) to the mid-porion (MP) plane. The Wilcoxon signed-rank test was computed to compare between pre- and postoperative data, and a p-value less than 0.05 was considered statistically significant.

RESULTS

The cohort comprised 24 subjects (50% females, 75% left-sided) with a mean age of 30.5 +/- 13.8 years. On 2D analysis, the significant fracture reduction was found: 4.78 vs. 1.22 mm, 1.78 vs. 0.40 mm, 3.50 vs. 0.07 mm, 3.06 vs. 0.55 mm, and 2.55 vs. 0.50 mm at zygomaticomaxillary, zygomaticofrontal, inferior orbital rim, zygomaticosphenoidal, and zygomaticotemporal landmarks. The 3D evaluations revealed the significant reduction of the differences between the left and right zygomatic surface to the porion plane (4.09 ± 2.12 vs. 0.46 ± 0.35 mm) and between the left and right ZA midpoints to the MP plane (4.89 ± 2.59 vs. 0.71 ± 0.44 mm) (p<0.001 for both 2D and 3D analyses).

CONCLUSIONS

The results of this study suggest that the real-time surgical navigation system can effectively guide the ORIF of zygomatic fractures. Future research studies should focus on the learning curve and cost-effectiveness analysis of this technique.

Scoping Zygomaticomaxillary Complex Fractures With the Eyes of Virtual Reality: Operative Protocol and Proposal of a Modernized Classification

INTRODUCTION

Fractures of the zygomaticomaxillary complex (ZMC) represent an extremely heterogeneous group of injuries to the midfacial skeleton. Traditionally, the diagnosis of such fractures was based on 2-dimensional radiograms and, more recently, on volumetric computed tomography (CT) scans, while the treatment was exclusively based on the surgeon's experience. Many classification attempts have been made in the past, but no paper has taken into account the importance of virtual surgical planning (VSP) in proving a modernized classification. The authors propose a classification based on the use of VSP which can guide the surgeon to identify the optimal reduction method and reproduce it in the operating room through the use of navigation.

METHODS

Patients with ZMC fractures were collected to create a study model. The VSP was used to generate 3-dimensional models of fractures. Fractured segments were duplicated and digitally put in the optimal reduction position. Repositioned fragments were overlapped to their original preoperative counterparts and exported to the surgical navigator to be navigated. Planned virtual reduction was overlaid to postoperative CT scan to assess the accuracy of reduction, explored using color maps and the calculation of root mean square error.

RESULTS

For all patients, the application of VSP was successfully accomplished. High accuracy was confirmed between the planned virtual reduction and the postoperative CT scan. A 5-item classification based on VSP is proposed. All patients were included in the presented subclasses.

CONCLUSIONS

The adoption of virtual planning in ZMC fractures allows for an improved study of the displacement of the fracture and might indicate to the surgeons the required maneuvers to achieve optimal reduction. The presented proposal of classification might be an aid to simplify the choice of the most appropriate reduction method and might provide a deeper insight into the morphologic characteristics of fractures.

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.

Intraoperative Image-Guided Navigation in Craniofacial Surgery: Review and Grading of the Current Literature

INTRODUCTION

Image-guided navigation has existed for nearly 3 decades, but its adoption to craniofacial surgery has been slow. A systematic review of the literature was performed to assess the current status of navigation in craniofacial surgery.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) systematic review of the Medline and Web of Science databases was performed using a series of search terms related to Image-Guided Navigation and Craniofacial Surgery. Titles were then filtered for relevance and abstracts were reviewed for content. Single case reports were excluded as were animal, cadaver, and virtual data. Studies were categorized based on the type of study performed and graded using the Jadad scale and the Newcastle-Ottawa scales, when appropriate.

RESULTS

A total of 2030 titles were returned by our search criteria. Of these, 518 abstracts were reviewed, 208 full papers were evaluated, and 104 manuscripts were ultimately included in the study. A single randomized controlled trial was identified (Jadad score 3), and 12 studies were identified as being case control or case cohort studies (Average Newcastle-Ottawa score 6.8) The most common application of intraoperative surgical navigation cited was orbital surgery (n = 36), followed by maxillary surgery (n = 19). Higher quality studies more commonly pertained to the orbit (6/13), and consistently show improved results.

CONCLUSION

Image guided surgical navigation improves outcomes in orbital reconstruction. Although image guided navigation has promise in many aspects of craniofacial surgery, current literature is lacking and future studies addressing this paucity of data are needed before universal adoption can be recommended.

Analysis of the accuracy of a novel preformed osteosynthesis plate for the reduction and fixation of zygomaticomaxillary complex fractures

INTRODUCTION

There has been a shift toward surgical treatment of ZMC (zygomaticomaxillary complex) fractures with open reduction and subsequent fixation in the past decades. Anatomically preformed osteosynthesis plates, already used in the field of craniomaxillofacial surgery for the treatment of fractures of the mandible and the orbit, might be a suitable option for ZMC fractures as well.

MATERIAL AND METHODS

A statistical shape model was created from 179 cranial CT scans. Based on this surface model, an anatomically preformed plate for the reduction and fixation of ZMC fractures was developed in 3 sizes (S, M, L). Virtual analysis of the accuracy of the plate was performed on a dataset consisting of 120 CT scans.

RESULTS

Within a determined tolerance range of 0-1.5 mm, analysis revealed a high accuracy of the plate in 70-87 % of the CT scans. The S-sized plate has the highest overall accuracy, whereas the L-sized plate has highest accuracy at the "base" region which is essential for the placement of the plate.

DISCUSSION

The newly developed plate can be placed via an intraoral approach and analysis of the plate has confirmed its accuracy to be sufficient to ensure an adequate fracture reduction and fixation. It thus might allow for a less extensive approach and less approaches/incisions necessary overall to reduce and fixate ZMC fractures.

New and emerging patient-centered CT imaging and image-guided treatment paradigms for maxillofacial trauma

This article reviews the conceptual framework, available evidence, and practical considerations pertaining to nascent and emerging advances in patient-centered CT-imaging and CT-guided surgery for maxillofacial trauma. These include cinematic rendering-a novel method for advanced 3D visualization, incorporation of quantitative CT imaging into the assessment of orbital fractures, low-dose CT imaging protocols made possible with contemporary scanners and reconstruction techniques, the rapidly growing use of cone-beam CT, virtual fracture reduction with design software for surgical pre-planning, the use of 3D printing for fabricating models and implants, and new avenues in CT-guided computer-aided surgery.

Clinical outcomes for minimally invasive primary and secondary orbital reconstruction using an advanced synergistic combination of navigation and endoscopy

BACKGROUND

Sequelae of inadequate orbital reconstruction include enophthalmos, hypoglobus, and diplopia. Accuracy of orbital reconstruction is largely subjective and especially difficult to achieve because of anatomic distortion in secondary or late reconstruction and in extensive injury. We combined computer navigation and endoscopy to perform accurate, aesthetic, and safe minimal-access primary and secondary orbital reconstruction.

METHODS

From 2013 to 2014, 24 patients underwent unilateral primary and secondary or late minimally invasive orbital reconstruction with mainly Medpor and/or titanium mesh by navigation and endoscopic assistance through transantral, transconjunctival, or upper blepharoplasty approaches. Mean follow-up was 13.8 months (range, 6.2 months to 2.8 years).

RESULTS

All orbital fractures were successfully reduced. Average enophthalmos among patients who underwent early reconstruction, late reconstruction, and multiorbital wall repair improved (p < .001) to 0.2 mm from 1.6, 2.6, and 2.6 mm, respectively. Hypoglobus and diplopia resolved in all. In early reconstruction patients, mean interorbital volume difference improved from 1.72 ± 0.87 to 0.53 ± 0.83 ml (P = .03). For late reconstruction patients, this difference improved from 3.41 ± 1.23 to 0.56 ± 0.96 ml (p < .001). There were no major complications during follow-up, and all were satisfied with their final appearance and function.

CONCLUSION

Navigation sharpens reconstructive accuracy and avoids injury to vital structures. Combined with endoscopic assistance for minimal-access reconstruction of wide-ranging orbital defects from primary to secondary or late cases and to extensive multiwall fractures, navigation facilitates minimal cosmetic incision and synergistic endoscope use and clearly optimizes aesthetic and functional outcomes, all with enhanced safety and unparalleled intraoperative visualization.

Customized Orbital Wall Reconstruction Using Three-Dimensionally Printed Rapid Prototype Model in Patients With Orbital Wall Fracture

BACKGROUND

It is difficult to restore original orbital contours because of their complex 3-dimensional structure. Moreover, slight implant malpositioning can result in enophthalmos or other complications. The authors describe our experience of using individualized prebent titanium-Medpor mesh implants and stereolithographic modeling in a series of patients who underwent orbital wall reconstruction.

METHODS

A consecutive series of 104 patients with orbital fractures received computer simulation-designed prebent titanium-Medpor mesh implants insertion. Preoperative computed tomography (CT) data were processed for each patient, and a rapid prototyping (RP) model was produced. The uninjured side was concurrently mirrored and superimposed onto the traumatized side to create a mirror image of the RP model. The authors fabricated the titanium-Medpor implants to intraoperatively reconstruct the 3-dimensional orbital structure. The prefabricated titanium-Medpor implants were inserted into the defective orbital wall and fixed. Postoperative CT images were immediately taken to evaluate the reconstructed contours and compare the preoperative and postoperative intraorbital volumes.

RESULTS

All reconstructions were successful without postoperative complications. The implants were correctly positioned in the sagittal, axial, and coronal planes relative to the original orbital contours. The mean preoperative intraorbital volumes of the uninjured and traumatized sides were 21.39 ± 1.93 and 23.17 ± 2.00 cm, respectively, and the postoperative mean intraorbital volume was 20.74 ± 2.07 cm.

CONCLUSIONS

Orbital reconstruction can be optimized using individually manufactured rapid prototype skull model and premolded synthetic scaffold by computer-aid of mirroring-reconstruction of 3-dimensional images and 3-dimensional printing techniques.

Salt as a new colored solid model for simulation surgery

BACKGROUND

Simulated craniomaxillofacial surgery is critical for planning the procedure, shortening operative time, and practicing the procedure. However, typical models are expensive, given their solid materials, and the surgical sensations do not accurately reflect the procedure performed using human bone. To solve these problems, a new solid salt model has been developed.

METHOD

Stereolithography data was generated using computed tomography data, and a salt model was created using a 3D inkjet printer. By extracting specific data for elements such as the teeth and mandibular canal, these elements were highlighted in the solid model using different colored material. Also, we compared the maximum load and plastic deformation of the salt model, a stereolithographic resin model, and a pig limb.

RESULT

The salt model had similar tenacity to bone, and the risk of damage to the teeth and inferior alveolar nerve was easily confirmed.

CONCLUSION

The material cost of the salt model is extremely low, and the salt model may provide a more accurate sensation of cutting human bone. Thus, this model is useful for both simulated operation and practice for inexperienced surgeons.

Rapid prototyping-assisted maxillofacial reconstruction

Rapid prototyping (RP) technologies have found many uses in dentistry, and especially oral and maxillofacial surgery, due to its ability to promote product development while at the same time reducing cost and depositing a part of any degree of complexity theoretically. This paper provides an overview of RP technologies for maxillofacial reconstruction covering both fundamentals and applications of the technologies. Key fundamentals of RP technologies involving the history, characteristics, and principles are reviewed. A number of RP applications to the main fields of oral and maxillofacial surgery, including restoration of maxillofacial deformities and defects, reduction of functional bone tissues, correction of dento-maxillofacial deformities, and fabrication of maxillofacial prostheses, are discussed. The most remarkable challenges for development of RP-assisted maxillofacial surgery and promising solutions are also elaborated.

[Interventional multidimodal hybrid unit: from pre-operative planning to immediate post-operative control]

INTRODUCTION

Computer assisted surgery has rapidly developed over the last decade, essentially due to the development of navigation and 3D virtual surgical planning and image fusion technologies. The recent introduction of intra-operative cone-beam CT scan (CBCT), which integrates flat panel technology, allows for high resolution bone imaging, the quality and accuracy of which is similar to the one obtained by conventional spiral CT scan. The combination of these two technologies in a "hybrid" operating unit enables the convergence of the pre-, intra- and post-operative steps in a linear computer-assisted processing chain, which optimises surgery accuracy, predictability and patient outcomes while potentially reducing costs, operating times and need for further surgical revision.

TECHNICAL NOTE

The "hybrid" unit includes: 1) the operating room (65 m(2)) equipped with horizontal laminar-flow, a mobile monoplane ceiling suspended C-arm CBCT scan system with a flat panel detector, a wireless navigation system, and an interactive wall-mount touch screen 2) the control room (18 m(2)) separated from the operating room by an X-ray lead protective glass window, including two separate computer workstations for 3D image integration and processing 3) the scrub room (17 m(2)) with two separate stainless steel surgical wash-basins. The intra-operative protocol includes the following steps: 1) elaboration of the patient specific pre-operative computed planning and simulation based on pre-operatively and/or intra-operatively acquired patient images 2) intra-operative navigational guidance setting 3) surgical procedure 4) intra-operative 3D CT imaging 5) suture.

Orbitozygomatic fractures with enophthalmos: analysis of 64 cases treated late

PURPOSE

To present our treatment experience in delayed orbitozygomatic fracture with enophthalmos and compare the results of traditional surgery, navigation-guided surgery, and 3-dimensional (3D) model-guided surgery in the Departments of Oral and Maxillofacial Surgery and Ophthalmology, Shanghai Ninth People's Hospital, Shanghai, China.

PATIENTS AND METHODS

This is a retrospective review of a consecutive clinical case series. From 2008 to 2010, 64 patients diagnosed with delayed orbitozygomatic fractures with enophthalmos were treated in the departments. Computed tomography (CT) scan and ophthalmologic examination were performed before surgery. Traditional surgery and computer-assisted treatment (navigation and 3D model) were used for zygoma reduction. Three materials were applied for orbital reconstruction: hydroxyapatite (HA), porous polyethylene (Medpor; Porex Surgical Inc, Newnan, GA), and titanium mesh. Zygomatic reduction and globe projection of different treatment methods were evaluated by postoperative CT scan and clinical follow-up visits.

RESULTS

Thirty-nine cases with enophthalmos (mean, 4.96 mm) had traditional surgery for fracture reduction and orbital reconstruction, whereas the other twenty-five cases with enophthalmos (mean, 5.71 mm) had computer-assisted surgery consisting of 3D models to pre-bend the titanium mesh for orbital reconstruction and plates for fracture fixation (n = 25) and navigation-guided surgery (n = 11). Postoperative CT with 3D reconstruction showed good zygomatic reduction in 74.3% of the cases with traditional surgery, 85.7% with computer-assisted 3D models only, and 100% with navigation-guided surgery. In the traditional surgery group, 74.2% of the cases had good postoperative globe projection (≤2 mm), 19.4% had mild enophthalmos (≤3 mm), and 6.5% had moderate enophthalmos (≤4 mm). In the group undergoing computer-assisted 3D model surgery, 75% of the cases had good globe projection and 25% had mild enophthalmos. In the navigation-guided surgery group, 90.9% of the cases had good globe projection and 9.1% had mild enophthalmos. Titanium mesh was used for orbital reconstruction in 47 cases (among which, 12 combined with Medpor or HA), whereas 12 had Medpor only and 5 had HA only. Good globe projection was acquired in 74% of the cases with titanium mesh only, 83% with combined materials, 67% with Medpor only, and 20% with HA only.

CONCLUSIONS

Computer-assisted surgery can improve the treatment results of delayed orbitozygomatic fracture with enophthalmos. Navigation-guided surgery with a 3D model and titanium mesh with Medpor are the best ways to treat delayed orbitozygomatic fractures with severe enophthalmos.

Rapid prototyping in craniofacial surgery: using a positioning guide after zygomatic osteotomy - A case report

INTRODUCTION

The management of post-traumatic deformity in the midface region poses challenges for the maxillofacial surgeon. Ensuring symmetry after zygomatic osteotomy can be difficult and precise positioning of the osteotomised bony fragments requires careful treatment planning. It may be necessary to use a coronal flap to allow the surgeon to compare the contralateral zygomatic bone to allow symmetrical reduction. The authors present a new technique for the positioning of osteotomised zygomatic bones using a combination of computer assisted surgical simulation and rapid prototyping.

METHOD

A patient presented to our unit with a post-traumatic zygomatic deformity. Using surgical simulation software the displaced zygomatic bone was osteotomised and placed in the idéal position on a three-dimensional computed tomography scan (3D CT). The position was determined by reference to the contralateral zygoma. In addition the repositioning of the soft tissues was simulated. A surgical guide which allowed intraoperative positioning of the osteotomised zygoma was manufactured by a rapid prototyping process. Use of the guide allowed a minimally invasive approach to the affected zygoma. The post-operative results were compared to the predicted outcome.

RESULTS

The post-operative appearance was satisfactory and corresponded well with the predicted result. There was a significant reduction in operative time compared to the previous management of similar cases.

Application of computer-aided three-dimensional skull model with rapid prototyping technique in repair of zygomatico-orbito-maxillary complex fracture

BACKGROUND

With the advent of CAD/CAM and rapid prototyping (RP), a technical revolution in oral and maxillofacial trauma was promoted to benefit treatment, repair of maxillofacial fractures and reconstruction of maxillofacial defects.

METHODS

For a patient with zygomatico-facial collapse deformity resulting from a zygomatico-orbito-maxillary complex (ZOMC) fracture, CT scan data were processed by using Mimics 10.0 for three-dimensional (3D) reconstruction. The reduction design was aided by 3D virtual imaging and the 3D skull model was reproduced using the RP technique. In line with the design by Mimics, presurgery was performed on the 3D skull model and the semi-coronal incision was taken for reduction of ZOMC fracture, based on the outcome from the presurgery.

RESULTS

Postoperative CT and images revealed significantly modified zygomatic collapse and zygomatic arch rise and well-modified facial symmetry.

CONCLUSIONS

The CAD/CAM and RP technique is a relatively useful tool that can assist surgeons with reconstruction of the maxillofacial skeleton, especially in repairs of ZOMC fracture.

Computer modeling and intraoperative navigation in maxillofacial surgery

PURPOSE

Recent advances in computer-modeling software allow reconstruction of facial symmetry in a virtual environment. This study evaluates the use of preoperative computer modeling and intraoperative navigation to guide reconstruction of the maxillofacial skeleton.

METHODS

Three patients with traumatic maxillofacial deformities received preoperative, thin-cut axial CT scans. Three-dimensional reconstructions, virtual osteotomies, and bony reductions were performed using MIMICS planning software (Materialise, Ann Arbor, MI). The original and "repaired" virtual datasets were then imported into an intraoperative navigation system and used to guide the surgical repair.

RESULTS

Postoperative CT scans and photographs reveal excellent correction of enophthalmos to within 1 mm in patient 1, significant improvement in symmetry of the nasoethmoid complex in patient 2, and reconstruction of the zygomaticomaxillary complex location to within 1 mm in patient 3.

CONCLUSION

Computer modeling and intraoperative navigation is a relatively new tool that can assist surgeons with reconstruction of the maxillofacial skeleton.

Minimal invasive reconstruction of posttraumatic hemi facial atrophy by 3-D computer-assisted lipofilling

Facial hemi atrophy is seen after trauma, Parry-Romberg syndrome and on other rare occasions. Since the aesthetic deficit is very obvious and irritating, facial reconstruction is often requested by these patients. In most cases the only option for sufficient reconstruction is free flap reconstruction, which represents the standard treatment. Recently in plastic surgery, various new techniques have been developed with the potential for multiple applications. Lipofilling has been presented primarily for the correction of cosmetic lesions or the reconstruction of minor soft tissue defects, but even reconstruction of larger soft tissue deficits is possible. The concept of using 3-D technology in facial reconstruction has multiple advantages. Primarily, the ideal final aesthetic outcome can be simulated by virtual reconstruction. Mathematic calculations deliver exact numbers in volume deficits, enabling precise planning of soft tissue substitution especially in lipofilling, ideally avoiding unnecessary corrections. Since autologous soft tissue reconstruction represents a dynamic process with periods of swelling as well as atrophy, quality control is required for achieving optimal results. Use of 3-D scanning has the advantage of reliable visualisation in soft tissue reconstruction without the limitations of harmful side effects. We present the history of a female suffering from the posttraumatic consequences of head injuries related to a car accident and the successful correction of her hemi facial atrophy by autologous lipofilling. Technical details and the potential of 3-D scanning in plastic surgery are discussed.