Mirror imaging and preshaped titanium plates in the treatment of unilateral malar and zygomatic arch fractures

Advances in Three-Dimensional Printing for Craniomaxillofacial Trauma Reconstruction: A Systematic Review

Craniomaxillofacial (CMF) fractures present significant challenges for plastic surgeons due to their intricate nature. Conventional methods such as autologous bone grafts have limitations, necessitating advancements in reconstructive surgery techniques. This study reviewed the use of three-dimensional printing for CMF trauma reconstruction using human studies. A systematic search of PubMed, EMBASE, and Google Scholar was conducted in February 2024 for case reports, case series, and clinical trials related to CMF trauma reconstruction using three-dimensional printing technology. The authors' systematic review included 20 studies and a total of 170 participants with CMF bone defects. In general, the authors observed low bias risk in analyzed case reports and series, serious bias risk in nonrandomized controlled trials, and moderate bias risk in randomized controlled trials. The printed objects included CMF structure model prototypes, patient-specific implants, and other custom surgical devices. Studies reveal successful outcomes, including restored facial symmetry and function, restored orbital occlusion, resolved enophthalmos and diplopia, achieved cosmetically symmetrical lower face reconstruction, and precise fitting of surgical devices, enhancing patient and surgeon comfort. However, complications such as local infection, implant exposure, and persistent diplopia were reported. Three-dimensional printed devices reduced surgery time but increased preparation time and production costs. In-house production options could mitigate these time and cost expenditures. Three-dimensional printing holds potential in CMF trauma reconstruction, addressing both functional and esthetic restoration. Nevertheless, challenges persist in implementing this advanced technology in resource-limited environments.

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.

Application of customized integration titanium mesh in the treatment of complicated zygomatic complex fractures: A prospective randomized clinical study

The present study aimed to quantitatively evaluate the outcomes of the application of customized integration titanium mesh (CITM) in treating unilateral complicated zygomatic complex fractures. A prospective, randomized, controlled clinical study was conducted. Patients were randomly divided into the experimental group who underwent treatment with CITM, and the control group who underwent treatment just with traditional titanium plates. The X² test and student t-test were used for statistical analyses. Twenty patients who required surgery for unilateral complicated zygomatic complex fracture were included in this study. The results showed that the mean of average distance (AD) between pre- and postoperative CT measurements was 0.487 mm in the experimental group and 1.173 mm in the control group (P < 0.001). Compared with the control group, the experimental group had superior zygomatico-facial symmetry (P＜0.05), a shorter average operation time (150 min versus 229 min; P < 0.001), and a higher rate of anatomic reduction (80.0% versus 30.0%; P＜0.05). In conclusion, CITM deserves to be promoted for the treatment of complicated zygomatic complex fractures. TRIAL REGISTRATION: www.chictr.org.cn (ChiCTR1800016818).

Reduction Malarplasty Using Customized Surgical Stent Based on 3D Virtual Surgery, CAD/CAM, and 3D Printing Technology: Case Series

ABSTRACT

The zygomatic bone is a structure that protrudes symmetrically on both sides of the midface and plays an important role in the overall aesthetic appearance of the face. Unlike Caucasians, the mesocephalic facial shape is predominant in Asians, and therefore, many people have a relatively laterally developed zygomatic bone. In Asians, when the zygomatic bone is excessively developed, it gives a strong and stubborn image, and aesthetically, many people want to reduce the zygomatic bone because they prefer an oval and slim face.To reduce the excessive zygomatic bone, a reduction malarplasty through an intraoral and preauricular approach has been performed. Although reducing the zygomatic bone is not a big problem in most cases of symmetric reduction malarplasty, it is not easy to produce surgical results as intended by the surgeon in asymmetric malar patients or patients requiring a three-dimensional (3D) change of zygoma. In addition, because of the mobility of the zygoma segment, it may be difficult to drill holes and fix plate after osteotomy. Moreover, these factors can increase the possibility of malunion or nonunion.In this study, cutting guides made with the aid of 3D virtual surgery, 3D printing, and customized titanium plates manufactured with the computer-aided design/computer-aided manufacturing technology are used for 8 patients to maximize the recovery of 3D symmetry and minimize complications through accurate fixation after surgery. During the surgical procedures, screw hole drilling and osteotomy were performed using a cutting guide, and then, the malar segment was fixed by matching the premade customized plates with the predrilled holes. As a result of checking the accuracy of the surgery by superimposing the postoperative 3D cone beam computed tomography image and virtual surgery data based on the skull base, the 2 images almost overlapped and no significant differences were observed, so it was confirmed that the operation was performed exactly as plannedWhen using the 3D technology, it is possible to perform a more accurate surgery in patients with asymmetry due to congenital anomalies or trauma as well as simple asymmetry, so it can be concluded that using the 3D technology can overcome the limitations and disadvantages of the conventional method as in the cases in this study. The accurate prediction of soft tissue is still insufficient, and further research is needed to overcome this limitation.

Use of modified 3D digital surgical guides in the treatment of complex mandibular fractures

The objective of this study was to evaluate the use of 3D modified digital surgical guide plates combined with preformed titanium plates in the treatment of complex mandibular fractures. Patients with complex mandibular fractures were randomized into three groups. Group A was treated with a combination of 3D modified digital surgical guide plates and preformed titanium plates, Group B was treated with preformed titanium plates only, and Group C was treated conventionally. The key design point of the guide plates is the "slot" structure, which is crucial for accurately locating the preformed titanium plate. Clinical outcomes, including facial symmetry, surgical accuracy, and maximum deviation were quantitatively assessed postoperatively. Twenty-two patients were recruited for this study, eight for Group A, six for Group B, and eight for Group C. Group A exhibited better postoperative clinical outcomes. Among three groups, significant improvements were found in Group A for facial symmetry (S1 [0.74 ± 0.17 mm, P < 0.001], S2 [0.86 ± 0.21 mm, P = 0.004], S3 [0.92 ± 0.26 mm, P < 0.001], S4 [0.32 ± 0.09 mm, P < 0.001], S5 [0.47 ± 0.16 mm, P = 0.042], S6 [0.35 ± 0.04 mm, P = 0.001], S10 [0.50 ± 0.31 mm, P = 0.048], S11 [0.97 ± 0.29 mm, P = 0.018]) and surgical accuracy (T1 [R, 0.56 ± 0.18 mm, P = 0.021], T1 [L, 0.60 ± 0.30 mm, P = 0.022], T2 [L, 0.76 ± 0.21 mm, P = 0.006], T4 [R, 0.37 ± 0.15 mm, P < 0.001], T4 [L, 0.40 ± 0.15 mm, P = 0.001], T8 [R, 0.40 ± 0.15 mm, P = 0.007], T8 [L, 0.31 ± 0.29 mm, P = 0.001], T9 [L, 0.51 ± 0.33 mm, P = 0.042], T10 [R, 0.58 ± 0.28 mm, P = 0.049], T10 [L, 0.53 ± 0.34 mm, P = 0.046], T11 [R, 0.54 ± 0.13 mm, P = 0.021], T12 [0.45 ± 0.16 mm, P = 0.003]). The ideal postoperative effect was found in Group A with maximum deviation analysis. 3D printed modified digital surgical guide plates can effectively improve treatment outcomes in complex mandibular fractures.

Cost Analysis for In-house versus Industry-printed Skull Models for Acute Midfacial Fractures

Industry-printed (IP) 3-dimensional (3D) models are commonly used for secondary midfacial reconstructive cases but not for acute cases due to their high cost and long turnaround time. We have begun using in-house (IH) printed models for complex unilateral midface trauma. We hypothesized that IH models would decrease cost and turnaround time, compared with IP models.

Zygomatico-Orbital Fracture-Dislocation in Surgical Treatment: Novel 3-Dimensional Software Automated Analysis

PURPOSE

The human capability to detect the degree of zygomatico-orbital (ZMO) fracture-dislocation in surgical treatment is unknown. The aim of this study was to examine the association between ZMO fracture-dislocation and injury etiology and treatment.

MATERIALS AND METHODS

We implemented a retrospective cross-sectional study, enrolled a sample composed of patients with an isolated unilateral ZMO fracture, and analyzed fracture-dislocation from computed tomography images with an automatic algorithm. The primary predictor variable was mean surface point-to-point dislocation (the mean distance of dislocation for all surface points in isolated ZMO fracture segments between the original position and after virtual repositioning). The primary outcome was the treatment choice (operative vs nonoperative). Other studied variables were gender, age group, injury mechanism, clinical asymmetry, and human-evaluated dislocation on computed tomography images. Descriptive and bivariate statistics were computed, and the threshold for statistical significance was set at P < .05.

RESULTS

The sample consisted of 115 patients with a mean age of 66.3 years, 66.1% of whom were male patients, and the most common cause of injury was falling on the ground (49.6%). Operative treatment was required in 58 patients (50.4%). A significant association was found between mean dislocation and operative treatment. Mean dislocation of operatively versus nonoperatively treated fractures was 2.39 mm versus 1.05 mm (P < .001). Mean fracture-dislocation was greatest in injuries caused by assault (2.41 mm) and smallest in motor vehicle accidents (1.08 mm) and ground-level falls (1.25 mm). The threshold of human-eye detection for ZMO fracture-dislocation was 1.97 mm.

CONCLUSIONS

The results of this study demonstrate that the threshold for operative treatment of ZMO fracture-dislocation is over 2 mm, which the human eye is able to detect. True dislocation is greater in younger patients than elderly patients and in injuries caused by assault compared with falling.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

Application of computer-assisted surgery techniques in the management of zygomatic complex fractures

Patients suffering from zygomatic complex fractures always present facial deformity and dysfunctions, and thereafter develop psychological and physiological problems. It is really hard to get an ideal prognosis for the zygomatic complex fractures because of the complicated anatomical structures. Computer-assisted surgery techniques, as the new emerging auxiliary methods, can optimize the surgical protocol, predict operation outcomes, and improve the accuracy and quality of the operation. Meanwhile the postoperative complications can be reduced effectively. This review aims to provide a comprehensive overview of the application of computer-assisted surgery techniques in the management of zygomatic complex fractures.

Mandibular Advancement Means Lower Facial Enlargement: A 2-Dimensional and 3-Dimensional Analysis

PURPOSE

Bilateral sagittal split osteotomy (BSSO) is frequently used to treat Class II malocclusion for functional and esthetic purposes, with expected changes in the profile. The goal of this study was to assess transversal changes in mandibular advancement by comparing 3-dimensional (3D) photogrammetric modifications and 2-dimensional (2D) radiographic enlargement.

MATERIALS AND METHODS

A cohort study was conducted of patients who underwent an isolated advancement BSSO (Obwegeser-Dal Pont II type) for a Class II malocclusion. All patients had 3D photogrammetric and 2D radiographic evaluations before and after surgery. Frontal cephalograms were used to measure the evolution of bigonial distance (BGD) and 3D photographs were used to measure the evolution of cutaneous BGD (CBGD).

RESULTS

Fourteen patients were included. Mean mandibular advancement was 6 mm. BGD (+6.1 mm; P < 10^-3) and CBGD (+4.2 mm; P = .0017) were significantly increased. The mean ratio of soft tissue response to transversal skeletal changes was 0.81.

CONCLUSION

This 2D and 3D analysis of transversal modifications shows that advancement with the BSSO is responsible for marked lower third facial enlargement. This parameter must be taken into account during the preoperative esthetic assessment to ensure the provision of pertinent information to the patient and the consideration of complementary surgical correction.

Use of 3D printed model as an aid in surgical removal of a rare occurrence of a compound odontome in the anterior mandible associated with impacted teeth

The use of 3D printing in the medical field has been well documented, with significant developments in fabrication of tissues, organs, customized prosthetics, implants, and anatomical models as well as pharmaceutical research. Its use in dentistry, however has been limited mainly to maxillofacial surgery and reconstruction, orthognathic surgery and trauma. Compound odontomes are usually prevalent in the anterior maxilla, however, their occurrence in the anterior mandibular region is rare. This case report highlights the effective usage of 3D printing as an aid in the surgical removal of a compound odontome and impacted incisors in the mandibular anterior region. The surgery was carried out under general anesthesia. A full thickness muco-periosteal flap was reflected and the compound odontome along with the impacted incisors were removed. The defect was restored using a mixture of autogenous scrapes harvested from the chin, xenograft and platelet-rich fibrin. Wound closure was done using 4-0 vicryl. A CBCT scan taken 1 year later confirmed uneventful healing and complete bone regeneration of the surgical defect.

Key words:3D printing, model, compound odontome, impacted, incisors.

Three Dimensional Osteometric Analysis of Mandibular Symmetry and Morphological Consistency in Cats

Objectives: The aim of this study was to describe a number of anatomical reference points which can be used to measure mandibular morphology and assess the degree of mandibular symmetry in a group of normal cats. Comparisons were then made between cats to evaluate correlations between morphological measurements and degree of inter-cat variation. This will provide data valuable evaluating and developing techniques for caudal mandibular fracture repair.

Methods: Twenty-seven mixed breed cats (26 Domestic Shorthaired and 1 Domestic Longhaired) with no history of head trauma, intact undamaged mandibles, both mandibular fourth premolars and first molars present which had a full skull CT scan were included in this study. Anatomical reference points were defined on maximum intensity projections of multiplanar reconstruction of the mandibles and measurements taken. The ratios between paired right and left measurements, and the ratio of jaw widths at the coronoid process and mandibular foramen were calculated. All analyses were performed using R version 3.3.3 and the multcomp library.

Results: None of the right:left ratios were detected as being significantly different from 1 and the coefficient of variation values were all very small showing that when cats deviate from the mean ratio they do so by only a small amount. Measurements analyzed to determine how consistent individual measurements were between cats showed that the most consistent measurement was the lateral ramus inclination angle. The least consistent measurements were ramus height and jaw width at the mental foramen. The correlation between pairs of measurements of the right and left ramus was analyzed and demonstrated a strong correlation between the height, width and length of the ramus.

Conclusions: This study has demonstrated a low level of asymmetry between contralateral mandibles in cats, a high level of consistency in the dimensions of mandibles between cats and a strong correlation between the height, width and length of the ramus.

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.

Multimaterial 3D printing preoperative planning for frontoethmoidal meningoencephalocele surgery

INTRODUCTION

Surgical correction of frontoethmoidal meningoencephalocele, although rare, is still challenging to neurosurgeons and plastic reconstructive surgeons. It is fundamental to establish reliable and safe surgical techniques. The twenty-first century has brought great advances in medical technology, and the 3D models can mimic the correct tridimensional anatomical relation of a tissue organ or body part. They allow both tactile and spatial understanding of the lesion and organ involved. The 3D printing technology allows the preparation for specific surgery ahead of time, planning the surgical approach and developing plans to deal with uncommon and high-risk intraoperative scenarios.

CASE PRESENTATION

The present report describes a case of frontoethmoidal encephalocele, (nasofrontal subtype) of a 19-month-old girl, whose surgical correction was planned using 3D printing modeling.

CONCLUSION

The 3D model allowed a detailed discussion of the aspects of the surgical approach by having tissues of different consistencies and resistances, and also predicting with millimetric precision the bilateral orbitotomy measurements. Moreover, it was a fundamental and valuable factor in the multidisciplinary preoperative discussion. This approach allowed reducing the time of surgery, accurately planning the location of the osteotomies and precontouring the osteosynthesis material. 3D models can be very helpful tools in planning complex craniofacial operative procedures.

Assessing symmetry of zygomatic bone through three-dimensional segmentation on computed tomography scan and "mirroring" procedure: A contribution for reconstructive maxillofacial surgery

PURPOSE

Surgical reconstruction of zygomatic bones in cases of traumatic injuries is a frequent event: assessment of symmetry is mandatory for a correct restoration of zygomatic shape, but the literature is discordant about its quantification. The purpose of this study is to show a novel method for assessing symmetry of zygomatic bone through mirroring of 3D models segmented on CT-scan.

MATERIALS AND METHODS

A total of 100 patients (50 male and 50 female), divided into two age groups (18-49 years and 50-92 years) were selected from the computed tomography (CT) scan database of a hospital in northern Italy. Zygomatic bones from each patient were segmented, and the left bone was automatically mirrored and registered on the right one according to the least point-to-point distance between the two surfaces. The mean and root mean square (RMS) distance between the two models was then calculated. Statistically significant differences according to sex and age groups were assessed through two-way analysis of variance (p < 0.05). In addition, the effect size of differences was calculated.

RESULTS

The method proved to be repeatable, with inter- and intraoperator errors lower than 5%. Overall, mean and RMS point-to-point distances were respectively 0.01 mm and 0.84 mm, without statistically significant differences according to sex or age (p > 0.05), and with negligible effect size.

CONCLUSION

This study provides an innovative method for assessing the symmetry of the zygomatic bone based on surface analysis. Results may provide useful indications for the reconstruction of zygomatic bones in maxillofacial surgery.

Prototyping for the treatment of late zygomatic-orbital fracture: A case report

INTRODUCTION

Zygomatic-orbital complex fractures are the most common facial traumas that can result in severe esthetic and functional sequelae. Surgical correction of these fractures is a delicate approach and prototyping is an excellent tool to facilitate this procedure.

PRESENTATION OF CASE

A 27-year-old man, a motorcycle accident victim, was hospitalized in the intensive care unit for 30days. After this period, facial fractures were treated surgically, leaving sequelae such as enophthalmos, dystopia and loss of projection of the zygomatic arch. A second intervention was planned after one year for reconstruction of the orbit with the help of prototyping. Better outcomes were achieved than in the first intervention.

DISCUSSION

This report permits to compare the result of conventional surgery and the use of a prototype in the same patient. Noticeably better outcomes were achieved with the second approach. Prototyping made the surgical procedure more predictable and reduced operative time because of the possibility of using preshaped titanium plates.

CONCLUSIONS

Prototyping was found to be an excellent option to overcome the deficiencies of the conventional technique, recovering the functional and esthetic characteristics of the patient's face and ensuring a markedly satisfactory outcome.

The use of 3D-printed titanium mesh tray in treating complex comminuted mandibular fractures: A case report

RATIONALE

Precise bony reduction and reconstruction of optimal contour in treating comminuted mandibular fractures is very difficult using traditional techniques and devices. The aim of this report is to introduce our experiences in using virtual surgery and three-dimensional (3D) printing technique in treating this clinical challenge.

PATIENT CONCERNS

A 26-year-old man presented with severe trauma in the maxillofacial area due to fall from height.

DIAGNOSIS

Computed tomography images revealed middle face fractures and comminuted mandibular fracture including bilateral condyles.

INTERVENTIONS AND OUTCOMES

The computed tomography data was used to construct the 3D cranio-maxillofacial models; then the displaced bone fragments were virtually reduced. On the basis of the finalized model, a customized titanium mesh tray was designed and fabricated using selective laser melting technology. During the surgery, a submandibular approach was adopted to repair the mandibular fracture. The reduction and fixation were performed according to preoperative plan, the bone defects in the mental area were reconstructed with iliac bone graft. The 3D-printed mesh tray served as an intraoperative template and carrier of bone graft. The healing process was uneventful, and the patient was satisfied with the mandible contour.

LESSONS

Virtual surgical planning combined with 3D printing technology enables surgeon to visualize the reduction process preoperatively and guide intraoperative reduction, making the reduction less time consuming and more precise. 3D-printed titanium mesh tray can provide more satisfactory esthetic outcomes in treating complex comminuted mandibular fractures.

3D-printing techniques in a medical setting: a systematic literature review

BACKGROUND

Three-dimensional (3D) printing has numerous applications and has gained much interest in the medical world. The constantly improving quality of 3D-printing applications has contributed to their increased use on patients. This paper summarizes the literature on surgical 3D-printing applications used on patients, with a focus on reported clinical and economic outcomes.

METHODS

Three major literature databases were screened for case series (more than three cases described in the same study) and trials of surgical applications of 3D printing in humans.

RESULTS

227 surgical papers were analyzed and summarized using an evidence table. The papers described the use of 3D printing for surgical guides, anatomical models, and custom implants. 3D printing is used in multiple surgical domains, such as orthopedics, maxillofacial surgery, cranial surgery, and spinal surgery. In general, the advantages of 3D-printed parts are said to include reduced surgical time, improved medical outcome, and decreased radiation exposure. The costs of printing and additional scans generally increase the overall cost of the procedure.

CONCLUSION

3D printing is well integrated in surgical practice and research. Applications vary from anatomical models mainly intended for surgical planning to surgical guides and implants. Our research suggests that there are several advantages to 3D-printed applications, but that further research is needed to determine whether the increased intervention costs can be balanced with the observable advantages of this new technology. There is a need for a formal cost-effectiveness analysis.

Advantages and disadvantages of 3-dimensional printing in surgery: A systematic review

BACKGROUND

Three-dimensional (3D) printing is becoming increasingly important in medicine and especially in surgery. The aim of the present work was to identify the advantages and disadvantages of 3D printing applied in surgery.

METHODS

We conducted a systematic review of articles on 3D printing applications in surgery published between 2005 and 2015 and identified using a PubMed and EMBASE search. Studies dealing with bioprinting, dentistry, and limb prosthesis or those not conducted in a hospital setting were excluded.

RESULTS

A total of 158 studies met the inclusion criteria. Three-dimensional printing was used to produce anatomic models (n = 113, 71.5%), surgical guides and templates (n = 40, 25.3%), implants (n = 15, 9.5%) and molds (n = 10, 6.3%), and primarily in maxillofacial (n = 79, 50.0%) and orthopedic (n = 39, 24.7%) operations. The main advantages reported were the possibilities for preoperative planning (n = 77, 48.7%), the accuracy of the process used (n = 53, 33.5%), and the time saved in the operating room (n = 52, 32.9%); 34 studies (21.5%) stressed that the accuracy was not satisfactory. The time needed to prepare the object (n = 31, 19.6%) and the additional costs (n = 30, 19.0%) were also seen as important limitations for routine use of 3D printing.

CONCLUSION

The additional cost and the time needed to produce devices by current 3D technology still limit its widespread use in hospitals. The development of guidelines to improve the reporting of experience with 3D printing in surgery is highly desirable.

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.

Accuracy of using computer-aided rapid prototyping templates for mandible reconstruction with an iliac crest graft

Background

This study aimed to evaluate the accuracy of surgical outcomes in free iliac crest mandibular reconstructions that were carried out with virtual surgical plans and rapid prototyping templates.

Methods

This study evaluated eight patients who underwent mandibular osteotomy and reconstruction with free iliac crest grafts using virtual surgical planning and designed guiding templates. Operations were performed using the prefabricated guiding templates. Postoperative three-dimensional computer models were overlaid and compared with the preoperatively designed models in the same coordinate system.

Results

Compared to the virtual osteotomy, the mean error of distance of the actual mandibular osteotomy was 2.06 ± 0.86 mm. When compared to the virtual harvested grafts, the mean error volume of the actual harvested grafts was 1412.22 ± 439.24 mm³ (9.12% ± 2.84%). The mean error between the volume of the actual harvested grafts and the shaped grafts was 2094.35 ± 929.12 mm³ (12.40% ± 5.50%).

Conclusions

The use of computer-aided rapid prototyping templates for virtual surgical planning appears to positively influence the accuracy of mandibular reconstruction.

Surgical planning, three-dimensional model surgery and preshaped implants in treatment of bilateral craniomaxillofacial post-traumatic deformities

PURPOSE

The purpose of the present study was to explore the treatment and outcomes of bilateral craniomaxillofacial post-traumatic deformities with surgical planning, 3-dimensional (3D) model surgery, and preshaped implants.

MATERIALS AND METHODS

We analyzed the preoperative computed tomography (CT) data and designed preliminary surgical plans for 3 patients with bilateral craniomaxillofacial post-traumatic deformities. 3D resin skull models were produced using rapid prototyping technology, and 3D model surgery was performed to determine the location, reduction direction, and shift distance of the osteotomy and to optimize the surgical plans. Titanium plates or mesh were preshaped on the models and then implanted into the patients. The complications, symmetry of the maxillofacial regions, mouth opening, and occlusion were observed 1 month postoperatively.

RESULTS

The patients had good recovery of their facial contour, occlusion, and mouth opening and acceptable symmetry of the bilateral maxillofacial regions. No complications were observed.

CONCLUSIONS

The combination of surgical planning, 3D model surgery, and preshaped implants can provide surgical accuracy and efficiency and good therapeutic outcomes in the treatment of bilateral craniomaxillofacial post-traumatic deformities.

Tactile surgical navigation system for complex acetabular fracture surgery

The authors describe a tactile surgical navigation system using custom 3-dimensional (3D) models of the bony pelvis for complex acetabular fracture surgery. The bone area of interest was extracted from the Digital Imaging and Communications in Medicine (DICOM) data of computed tomography scans. A standard triangulated language file was used to create 3D models of the bony pelvis by layered manufacturing using a 3D printer and non-cytotoxic, sterilizable, acrylic-based photopolymers. No infections and no toxic or other adverse events were observed. The models were useful for preoperative assessment, planning, and simulation; intraoperative assessment; obtaining informed consent; and education.

Computer-assisted zygoma reconstruction with vascularized iliac crest bone graft

BACKGROUND

The reconstruction of zygoma is a challenge with regard to aesthetic and reconstructive demands.

METHODS

Pre-operative CT data were imported into specific surgical planning software. The mirror-imaging technique was used. A surgical guide transferred the virtual surgery plan to the operation site, whereby it fitted uniquely to the iliac donor site. A postoperative CT scan was obtained for comparing the actual postoperative graft position and shape with the pre-operative virtual simulation.

RESULTS

A mean difference of 0.71 mm (SD ± 1.42) for the shape analysis and 3.53 mm (SD ± 3.14) for the graft position was determined. The calculation of the closest point distance showed a surface deviation of < 2 mm for the shape analysis with 83.6% of values and for the graft position with 35.7% of values.

CONCLUSION

Virtual surgical planning is a suitable method for zygoma reconstruction with vascularized iliac crest bone graft, with good accuracy for restoring the three-dimensional anatomy.

Digital surgical templates for managing high-energy zygomaticomaxillary complex injuries associated with orbital volume change: a quantitative assessment

PURPOSE

This study sought to introduce 3-dimensional (3D) virtual surgical planning and digital rapid-prototyping templates for zygomaticomaxillary complex (ZMC) injuries associated with orbital volume change and to evaluate the surgical outcomes quantitatively.

PATIENTS AND METHODS

Eight patients who underwent open reduction and fixation for a ZMC injury with orbital volume change were studied. Computed tomographic (CT) scan of the zygomaticomaxillary area was performed before the operation in each case. Scanned data were converted into 3D models using Mimics software (Materialise, Brussels, Belgium) for surgical designs. Virtual surgical reductions and correlated guiding templates were designed using Mimics and Magics software (Materialise). The operations were performed with the help of prefabricated templates to reduce the fractures. A postoperative CT scan of each patient was obtained within 2 weeks after surgery, and quantitative measurements were made to assess the surgical outcomes. Preoperative volumes of the bilateral orbits were compared, and concordance with postoperative volumes of the bilateral orbits was assessed. Twenty-one pairs of distances from 7 marker points to 3 reference planes were measured to assess postoperative facial symmetry.

RESULTS

Volumes of the injured orbits were significantly different from volumes of the uninjured orbits preoperatively (P < .05), whereas bilateral orbital volumes showed no statistically significant difference postoperatively (P > .05). In addition, 19 of the 21 pairs of bilateral distances showed no significant difference postoperatively (P > .05).

CONCLUSIONS

Quantitative assessment showed that digitally designed, rapid-prototyping templates for ZMC fractures have a positive impact on restoring facial symmetry and concordance of bilateral orbital volumes.

3-D analysis of dislocation in zygoma fractures

OBJECTIVE

When fractured, zygomas rotate and dislocate. The present study quantitatively elucidates the pattern of the rotation.

METHODS

50 patients with tri-pod-type zygoma fractures were involved in this study. After defining a 3-dimensional coordinate system--consisting of the M-L axis (the axis directed from the medial to lateral side of the skull), I-S axis (directed from the inferior to superior side), and P-A axis (directed from the posterior to anterior side), the degree with which the fractured zygomas rotated around each of these axes was measured using 3-dimensional graphic software. Thereafter, the tendency of the rotation was compared between the three rotational axes.

RESULTS

Rotation around the I-S axis was the most frequent with a 96% incidence, followed by a substantial margin by rotation around the M-L axis with a 26% incidence; rotation around the P-A axis was rare, with an incidence of 10%. Furthermore, the degree of P-A axis rotation was minor compared to I-S and M-L axis rotations.

CONCLUSION

The main factor of zygoma dislocation in zygoma fracture is rotation around the I-S axis. This finding is helpful for effective performance to reposition fractured zygomas.

Fat graft transfer in children's facial malformations: a prospective three-dimensional evaluation

INTRODUCTION

Autologous fat grafting for volume augmentation in soft tissues has grown in popularity in the paediatric plastic surgery community, despite a lack of quantifiable evidence of graft survival and predictable outcomes for child patients. The objective of this study is to quantify, through an objective method, the rate of survival of fat grafting in children's reconstructive surgery.

METHODS

Clinical evaluation of all children was performed under standardised conditions in a prospective fashion with a 1-year follow-up. All patients, under 18 years of age, were photographed with a three-dimensional imaging system. Data were analysed with three-dimensional analysing software to quantify the volume improvements postoperatively and during the follow-up.

RESULTS

Eleven children were included and followed up for 12 months. The mean age was 7.4 years. The mean amount of fat grafted was 13 cm3. At the end of the follow-up, the mean survival rate of the fat grafted was 40%. Complementary fat grafts were needed in 27% of the cases. No significant complications occurred.

CONCLUSION

Until now, the literature has failed to provide objective evidence of fat survival in children. This study, using three-dimensional data, showed a 40% survival of grafted fat. The use of three-dimensional photographs and analysis has great clinical potential for surgical planning and follow-up.

Evaluation of computer-assisted jaw reconstruction with free vascularized fibular flap compared to conventional surgery: a clinical pilot study

BACKGROUND

The introduction of computer-assisted surgery was a milestone in functional reconstructions of facial skeletal defects.

PATIENTS AND METHODS

We compared five computer-assisted and five conventional reconstructions with fibular grafts in the course of a pilot study. A rapid prototyping guide translated the computer-assisted surgery plan into intraoperative utilizable models. We intraoperatively measured the time needed for shaping the graft to the recipient site and the ischaemic time. Furthermore, the size of donor site defect compared to the required transplant length was evaluated.

RESULTS

Shaping procedure and ischaemic time turned out significantly shorter when compared to conventional surgery without cutting guide (p = 0.014). Using surgical guides, there was no change between the defect size of the fibula and the necessary transplant size. In conventional surgery, a mean change of 1.92 cm occurred (p = 0.001).

CONCLUSION

The surgical guide significantly reduced shaping time and consequently ischaemic time. These factors can influence flap survival. The fibular donor site defect was downsized.