Cost-Effectiveness Analysis for Computer-Aided Surgical Simulation in Complex Cranio-Maxillofacial Surgery

Does the type of planning in orthognathic surgery influence patient satisfaction?

PURPOSE

To determine if the method of orthognathic surgery planning used-computer aided surgical simulation (CASS) versus analog model surgery-influenced patients' post-operative satisfaction. The authors hypothesized that there was no difference in patient satisfaction based on the type of planning in orthognathic surgery.

METHODS

This was a single-site, observational, retrospective cohort study consisting of a standardized survey aimed to be given to all patients who had orthognathic surgery at the authors' institution over a 6-year period. Patients were asked to complete a survey questionnaire that consisted of eight questions, each utilizing a five-point Likert scale.

RESULTS

There were 643 patients initially identified with 401 potential subjects meeting the inclusion criteria. Of these 401 patients, the survey was successfully administered to 161. Patients whose orthognathic surgery was planned virtually were not only significantly more likely to be satisfied with their appearance post-operatively, but also more likely to go through with surgery again if they could choose to (p < 0.05). CASS patients were also more likely to identify that their surgery was planned virtually. When stratified by age, younger patients were more likely to have read about CASS. When each survey question was stratified based on the type of surgery that was performed, there were no significant differences.

CONCLUSION

Patients whose surgeries were virtually planes were significantly more likely than model surgery patients to be satisfied with their post-operative appearance as well as with their decision to have orthognathic surgery. CASS has proven to be an accurate, time-saving, and potentially cost-saving tool for surgeons. Based on the results of this study, the type of surgical planning method matters for post-operative patient satisfaction with their appearance.

Immediate placement of extra-short implants in refined scapula tip microvascular free flaps: In house virtual planning and surgical technique - Proof of concept

Scapula tip flaps have been introduced in the literature as an ideal surgical treatment option for large defects in the horizontal plane of the maxilla. This article aims to present a unique step by step protocol for a near total maxillectomy with a pterygoid bone resection and consecutive microvascular reconstruction with a harvested scapula tip flap. The protocol includes immediate placement of extra-short implants in donor bone with the aid of Virtual Surgical Planning (VSP), and an in-house 3D printing of medical 3D models and surgical guides. So far, there has been no presented surgical technique combining immediate implant placement in the scapula region with simultaneous microvascular repair. This technique allows: tumour resection; flap harvesting; extra-short implant placements and reconstruction to be performed in one simultaneous procedure. The technique is presented with illustrations, VSP (presented on videos), radiographs, and surgical findings. We discovered that this refinement of the scapula tip surgery has enabled reconstructive procedures to be performed at the same time as implant placements, providing expedited functional and aesthetic outcomes in selected cases. Moreover, modification of the surgical technique could enhance the competence of the oropharyngeal edge. In conclusion, this new surgical protocol utilizing VSP, 3D models and simultaneous extra-short implant placement provides indispensable advantages for such a complicated surgical procedures, while significantly shortening the duration of surgery.

Computer Guided Generated Dual-Purpose Splint for Bilateral Sagittal Split Osteotomy

Purpose

to evaluate the efficacy of dual-purpose computer-generated splint in guiding the proximal and the distal segment in bilateral sagittal split osteotomy.

Patients and Method

It was a prospective case series study directed on 8 class III patients indicating the need of maxillary advancement and mandibular set back by bilateral sagittal split osteotomy. A CAD/CAM splint is generated to guide the distal segment to the stable maxilla and at the same time a grooved extension to engage the proximal segment ensuring the condyle in its planned position during fixation. The primary outcome was measured by calculating the difference between the pre- and post-operative condylar segment position.

Results

The present study included five female patient and three male patient with mean age of 28.4 ± 5.1 years. The accuracy of the splint in positioning the mandibular proximal segment showed promising results ranging from 2.59 to 0.49.

Conclusion

The dual-purpose splint introduced in this study showed satisfied results in maintaining the pre-operative condylar position while securing the distal segment in the desired plan.

The untold history of planning in orthognathic surgery: a narrative review from the beginning to virtual surgical simulation

We aimed to produce a narrative review of planning orthognathic surgery, chronologically. Also, to present flaws of methods and the future of orthognathic surgery planning. The search was carried out mainly in PubMed, SCOPUS, Embase, and Cochrane databases. Also was complemented by manual search in reference lists from identified studies and in grey literature. The first orthognathic surgery was reported in 1849, and it took more than a century for the development of the traditional orthognathic 2D planning. Besides the advances, surgeons observed failures and lacks on 2D method in representing with reliability the facial and maxillary tridimensional structure (3D). With technological developments in 90s and 2000s, methodological improvements were granted, and the 3D protocol was created. The CASS and Charlotte protocols were the earliest 3D planning protocols conceived. Since then, some steps were simplified, and new technologies are being developed and added to create a more reliable and precise way of planning orthognathic surgery.

Precision medicine using patient-specific modelling: state of the art and perspectives in dental practice

The dental practice has largely evolved in the last 50 years following a better understanding of the biomechanical behaviour of teeth and its supporting structures, as well as developments in the fields of imaging and biomaterials. However, many patients still encounter treatment failures; this is related to the complex nature of evaluating the biomechanical aspects of each clinical situation due to the numerous patient-specific parameters, such as occlusion and root anatomy. In parallel, the advent of cone beam computed tomography enabled researchers in the field of odontology as well as clinicians to gather and model patient data with sufficient accuracy using image processing and finite element technologies. These developments gave rise to a new precision medicine concept that proposes to individually assess anatomical and biomechanical characteristics and adapt treatment options accordingly. While this approach is already applied in maxillofacial surgery, its implementation in dentistry is still restricted. However, recent advancements in artificial intelligence make it possible to automate several parts of the laborious modelling task, bringing such user-assisted decision-support tools closer to both clinicians and researchers. Therefore, the present narrative review aimed to present and discuss the current literature investigating patient-specific modelling in dentistry, its state-of-the-art applications, and research perspectives.

NeuroPlan: A Surgical Planning Toolkit for an MRI-Compatible Stereotactic Neurosurgery Robot

The adoption of robotic image-guided surgeries has enabled physicians to perform therapeutic and diagnostic procedures with less invasiveness and higher accuracy. One example is the MRI-guided stereotactic robotic-assisted surgery for conformal brain tumor ablation, where the robot is used to position and orient a thin probe to target a desired region within the brain. Requirements such as the remote center of motion and precise manipulation, impose the use of complex kinematic structures, which result in non-trivial workspaces in these robots. The lack of workspace visualization poses a challenge in selecting valid entry and target points during the surgical planning and navigation stage. In this paper, we present a surgical planning toolkit called the "NeuroPlan" for our MRI-compatible stereotactic neurosurgery robot developed as a module for 3D Slicer software. This toolkit streamlines the current surgical workflow by rendering and overlaying the robot's reachable workspace on the MRI image. It also assists with identifying the optimal entry point by segmenting the cranial burr hole volume and locating its center. We demonstrate the accuracy of the workspace rendering and burr hole parameter detection through both phantom and MR-images acquired from previously conducted animal studies.

The neurosensory deficit of inferior alveolar nerve following bilateral sagittal split osteotomy: a prospective study

OBJECTIVES

Investigation in Saudi Arabia or the Arab Gulf States to assess the unfavorable impacts of the bilateral sagittal split osteotomy (BSSO) is non-existent, so questions have been raised about the success rate of this operation and the frequency of unwilling outcome. To address these worries, we directed a case series study to evaluate the hypoesthesia, a type of neurosensory deficit (NSD) of the inferior alveolar nerve (IAN) after BSSO, and if the hypoesthesia outcome will improve if the surgeries performed by a single surgeon.

PATIENTS AND METHODS

This was a prospective case series study for the patient who underwent BSSO in a medical complex that is considered one of the largest in Saudi Arabia (Riyadh). The inclusion criteria include patient aged 18-40 years, any gender, and American Society of Anesthesiologists (ASA) class I. They will undergo BSSO for either mandibular, retrognathia, prognathic, or to follow the maxilla. The outcome will be measured after evaluating the neurosensory by four means light touch (LT), pinprick (PP), 2-point discrimination (2PD), and thermal sensations (TT) in four repeated measurements (preoperatively, 1 week, 1 month, 3 months postoperatively) as the primary outcome. Other confounding factors were the secondary outcome (age, gender, visualization of the I.A.N, the type of mandibular movement, split favorability, mandibular canal location, and patient reports about paresthesia or dysesthesia on any given side); these data analyses were carried out using SPSS ver. 25 data processing software.

RESULTS

The nerve was visible in 93% of cases. During the operation, none of the nerves was transected. Hypoesthesia on the first follow-up was 94% of cases for LT, 92% for PP, 82% for TT, and 100% for the 2PD. On the last follow-up, the patients still had hypoesthesia for the LT 51%, PP 35%, TT41%, and 2PD 55%; age and sex did not significantly affect hypoesthesia outcomes. Nerve visibility and inferior alveolar nerve canal (IAC) distance did not influence the results. The level of confidence for all tests was set at p < 0.05.

CONCLUSIONS

The 2PD sensation was the most affected sense on the last visit, and the right side of the chin and lower lip was affected most both on early and long-term follow-up due to several reasons. A 3-month period was enough as a recovery time to restore 100% of neurological sensation for 45% of the sample, which is similar to several studies in the literature. A single surgeon did not show superior result compared to two surgeons' literature papers. Advancement movement was associated with a high percentage of hypoesthesia.

Establishing a point-of-care additive manufacturing workflow for clinical use

Additive manufacturing, or 3-Dimensional (3-D) Printing, is built with technology that utilizes layering techniques to build 3-D structures. Today, its use in medicine includes tissue and organ engineering, creation of prosthetics, the manufacturing of anatomical models for preoperative planning, education with high-fidelity simulations, and the production of surgical guides. Traditionally, these 3-D prints have been manufactured by commercial vendors. However, there are various limitations in the adaptability of these vendors to program-specific needs. Therefore, the implementation of a point-of-care in-house 3-D modeling and printing workflow that allows for customization of 3-D model production is desired. In this manuscript, we detail the process of additive manufacturing within the scope of medicine, focusing on the individual components to create a centralized in-house point-of-care manufacturing workflow. Finally, we highlight a myriad of clinical examples to demonstrate the impact that additive manufacturing brings to the field of medicine.

Outcome of full digital workflow for orthognathic surgery planning in the treatment of asymmetric skeletal class III deformity

BACKGROUND/PURPOSE

Studies have reported the advantages of digital imaging-assisted orthognathic surgery planning, but there is scarce information about a full digital planning modality. This study evaluated the 3D cephalometric-based and patient-reported outcomes of a full digital workflow for orthognathic surgery planning in the treatment of asymmetric maxillomandibular disharmony.

METHODS

A postoperative 3D image dataset of 30 Taiwanese Chinese patients with asymmetric skeletal Class III deformities who underwent full digital planning for two-jaw surgery were retrieved from the authors' database. The 3D cephalometric data (dental, skeletal, and soft tissue evaluations) were compared to the ethnicity-matched 3D cephalometric normative values. Patient-reported outcome measure tools regarding postoperative overall appearance and satisfaction with facial areas (ranging from 0 to 100 and 0 to 10, respectively) were administered. The number of needed or requested revisionary surgery was collected.

RESULTS

No difference (all p > 0.05) was observed between the orthognathic-surgery-treated patients and the normative value for most of the tested 3D cephalometric parameters, with the exception (p < 0.05) of three mandible and occlusal-plane-related parameters. Both patient-reported outcome measure tools showed that patients' satisfaction with their postoperative appearance was high for overall face (89.7 ± 4.5) and specific facial regions (nose, 7.1 ± 1.3; lip, 8.3 ± 1.6; upper gum, 8.5 ± 1.2; cheek, 8.8 ± 1.1; chin, 9.2 ± 1.2; and teeth, 9.3 ± 0.8), with no need for revisionary surgery.

CONCLUSION

The patients treated with a full 3D digital planning-assisted two-jaw surgery had a similar 3D dental relation, facial convexity, and symmetry compared to healthy ethnicity-matched individuals, and they reported higher satisfaction levels with their postoperative facial appearance results.

Estimating Reference Shape Model for Personalized Surgical Reconstruction of Craniomaxillofacial Defects

OBJECTIVE

To estimate a patient-specific reference bone shape model for a patient with craniomaxillofacial (CMF) defects due to facial trauma.

METHODS

We proposed an automatic facial bone shape estimation framework using pre-traumatic conventional portrait photos and post-traumatic head computed tomography (CT) scans via a 3D face reconstruction and a deformable shape model. Specifically, a three-dimensional (3D) face was first reconstructed from the patient's pre-traumatic portrait photos. Second, a correlation model between the skin and bone surfaces was constructed using a sparse representation based on the CT images of training normal subjects. Third, by feeding the reconstructed 3D face into the correlation model, an initial reference shape model was generated. In addition, we refined the initial estimation by applying non-rigid surface matching between the initially estimated shape and the patient's post-traumatic bone based on the adaptive-focus deformable shape model (AFDSM). Furthermore, a statistical shape model, built from the training normal subjects, was utilized to constrain the deformation process to avoid overfitting.

RESULTS AND CONCLUSION

The proposed method was evaluated using both synthetic and real patient data. Experimental results show that the patient's abnormal facial bony structure can be recovered using our method, and the estimated reference shape model is considered clinically acceptable by an experienced CMF surgeon.

SIGNIFICANCE

The proposed method is more suitable to the complex CMF defects for CMF reconstructive surgical planning.

Three-Dimensional Computer-Assisted Orthognathic Surgery: Traditional Hybrid Versus Full Digital Planning Models

PURPOSE

Three-dimensional (3D) computer-aided planning has truly revolutionized orthognathic surgery (OGS) treatment, but no study has compared the traditional hybrid and full 3D digital planning models. This study compared these virtual planning models in the treatment of asymmetric maxillomandibular disharmony.

METHODS

Young adult patients with an asymmetric skeletal class III deformity who underwent 3D computer-aided 2-jaw OGS using hybrid (alginate dental impression, 2D cephalometric tracings, manual-guided stone model surgery, occlusion setup, and splint fabrication; n = 30) or full digital (laser-scanned dentition, 3D cephalometric tracings, virtual-based occlusion setup and surgery, and computer-generated surgical splint; n = 30) planning models were consecutively recruited. Preoperative and postoperative 3D cephalometric analyses (dental relation, skeletal assessments based on sagittal and frontal views, and soft tissue evaluations) were adopted for intragroup and intergroup comparisons. Postoperative patient-perceived satisfaction with facial appearance was also recorded.

RESULTS

Both hybrid and full digital planning groups had significant (all P < 0.05) improvements after surgery with respect to facial convexity, incisor overjet, and frontal symmetry parameters. The full 3D digital planning-based OGS treatment had similar (all P > 0.05) 3D cephalometric-derived outcomes (preoperative, postoperative, and treatment-induced change data) and patient-perceived outcomes compared with the traditional hybrid 3D planning method.

CONCLUSIONS

For the decision-making process in selecting the planning model, multidisciplinary teams could consider additional parameters such as patient comfort, storage needs, convenience for data reuse, overall planning time, availability, and costs.

Computer-Aided Design and Manufacture of Intraoral Splints: A Potential Role in Cleft Care

BACKGROUND

Nasoalveolar molding is a nonsurgical modality for the treatment of cleft lip and palate that uses an intraoral splint to align the palatal shelves. Repeated impressions are needed for splint modification, each carrying risk of airway obstruction. Computer-aided design and manufacturing (CAD/CAM) has the ability to simplify the process. As a precursor to CAD/CAM splint fabrication, a proof-of-concept study was conducted to compare three-dimensional splints printed from alginate impressions versus digital scans. We hypothesized that intraoral digital scanning would compare favorably to alginate impressions for palate registration and subsequent splint manufacture, with decreased production times.

METHODS

Alginate and digital impressions were taken from 25 healthy teenage volunteers. Digital impressions were performed with a commercially available intraoral scanner. Plaster casts made from alginate impressions were converted to Standard Triangle Language files. Patient-specific matched scans were evaluated for total surface area with the concordance correlation coefficient. Acrylic palatal splints were three-dimensionally printed from inverse digital molds. Subjective appliance fit was assessed using a five-point scale.

RESULTS

A total of 23 participants were included. Most subjects preferred digital impression acquisition. Impression methods showed moderate agreement (concordance correlation coefficient 0.93). Subjects rated splints from digital impressions as having a more precise fit (4.4 versus 3.9). The digital approach decreased impression phase time by over 10-fold and overall production time by 28%.

CONCLUSIONS

CAD/CAM has evolved extensively over the past two decades and is now commonplace in medicine. However, its utility in cleft patients has not been fully realized. This pilot study demonstrated that CAD/CAM technologies may prove useful in patients requiring intraoral splints.

Multicentre evaluation of the interest in planned surgery for mandibular reconstruction with fibula free flap: a retrospective cohort study

PURPOSE

The aim of this study was to determine the impact and cost-effectiveness of virtual surgical planning during fibula free flap mandibular reconstruction on peri- and postoperative data.

METHODS

We conducted a retrospective cohort study from January 2012 to December 2016 in four French university centres.

RESULTS

Three hundred fibula free flaps for mandibular reconstruction were performed in 294 patients. Surgeries were planned in 29.7% of cases (n = 89). There was no significant difference in the rate of negative-margins excision, median length of hospital stay, operative time, and early complications between planned and non-planned surgeries. Morphological analysis revealed a higher rate of centred occlusion in planned patients (satisfactory alignment of interincisal points: Planned 65.5% vs Non-Planned 33.3%, p = 0.006).

CONCLUSION

In mandibular reconstruction by fibula free flap, the additional cost generated by virtual surgical planning does not seem to be balanced by savings resulting from a shorter operative course, a reduced hospital stay, or a reduction in postoperative complications. However, virtual surgical planning may provide a higher rate of centred occlusion. Long-term benefits should be assessed by further studies.

The use of 3D virtual surgical planning and computer aided design in reconstruction of maxillary surgical defects

PURPOSE OF REVIEW

The present review describes the latest development of 3D virtual surgical planning (VSP) and computer aided design (CAD) for reconstruction of maxillary defects with an aim of fully prosthetic rehabilitation. The purpose is to give an overview of different methods that use CAD in maxillary reconstruction in patients with head and neck cancer.

RECENT FINDINGS

3D VSP enables preoperative planning of resection margins and osteotomies. The current 3D VSP workflow is expanded with multimodal imaging, merging decision supportive information. Development of more personalized implants is possible using CAD, individualized virtual muscle modelling and topology optimization. Meanwhile the translation of the 3D VSP towards surgery is improved by techniques like intraoperative imaging and augmented reality. Recent improvements of preoperative 3D VSP enables surgical reconstruction and/or prosthetic rehabilitation of the surgical defect in one combined procedure.

SUMMARY

With the use of 3D VSP and CAD, ablation surgery, reconstructive surgery, and prosthetic rehabilitation can be planned preoperatively. Many reconstruction possibilities exist and a choice depends on patient characteristics, tumour location and experience of the surgeon. The overall objective in patients with maxillary defects is to follow a prosthetic-driven reconstruction with the aim to restore facial form, oral function, and do so in accordance with the individual needs of the patient.

Traditional Versus Virtual Surgery Planning of the Fronto-Orbital Unit in Anterior Cranial Vault Remodeling Surgery

BACKGROUND

Craniosynostosis correction surgery is a complex procedure, which involves complete dismantling and reassembly of the cranial vault components. The traditional planning method for these surgeries results in increased intra-operative time owing to its highly subjective nature. The advent of virtual surgical planning (VSP) platform has lead to a greater pre-operative insight and precision outcome in calvarial remodeling surgeries. The purpose of this paper is to evaluate intra-operative time and blood loss difference as a measure of surgical efficiency between VSP based template guided Anterior Cranial Vault Reconstruction (ACVR) with Fronto-Orbital Unit Advancement (FOUA) and the traditional surgeries.

METHODS

Data were collected from patients who underwent ACVR with FOUA in our unit. Patients were divided into 2 groups, Template Fronto-Orbital Unit (TFOU) group and Non-template Fronto-Orbital Unit (NFOU) group. In TFOU group, Virtual planning along with fabrication of Template guide was carried out. Patients undergoing ACVR using traditional techniques were categorized as NFOU group. A comparative prospective analysis was carried out in terms of Intra-operative time duration and blood loss. Student 't' test was used to compare the means of the 2 groups.

RESULTS

A total of 10 patients were included in the present study. There were 5 control (NFOU) and 5 TFOU cases. There was a significant decrease in the operating time in TFOU group compared to the NFOU group. TFOU group also showed reduced intra-operative bleed compared to the NFOU group.

CONCLUSION

Virtual surgical planning (VSP) and 3D modeling with prefabricated template guide augurs reliable outcomes and portends the possibility of lesser intra-operative time. It is a valuable tool, which offers enormous benefits in terms of precise pre-surgical planning with predictive results.

Current Orthognathic Practice in India: Do We Need to Change?

The last decade or so has seen paradigm shifts in the various aspects of orthognathic surgery. A lot of these changes are to do with digitalization of the orthodontic-surgical workflow, optimization of surgery-first protocols, virtual surgical planning-based 3D printing solutions and changing patient-health-care dynamics. The aim of this article is to provide evidence-based recommendations that are both practical and economically viable for the current orthognathic practice in India.

Outcomes of conventional versus virtual surgical planning of orthognathic surgery using surgery-first approach for class III asymmetry

OBJECTIVES

To determine if patient outcome variables differ between conventional and virtual surgical planning of orthognathic surgery for class III asymmetry.

MATERIAL AND METHODS

This retrospective case-control study examined 95 patients with class III asymmetry who had been consecutively treated with at least a Le Fort I osteotomy and a bilateral sagittal split osteotomy with a surgery-first approach. Two groups were examined: 51 patients treated with conventional surgical planning and 44 with virtual surgical planning. After treatment, quantitative assessment was determined with measurements of midline symmetry, contour symmetry, and overall facial symmetry using standardized frontal photographs. Subject assessments were analyzed with questionnaires regarding self-perception of overall appearance, satisfaction with appearance, and quality of life.

RESULTS

Conventional and virtual surgical planning resulted in significant improvements in outcomes for all patients. However, facial midline and overall facial symmetry were significantly greater for the virtual compared with the conventional group. There were no significant differences in subjective measures of appearance, satisfaction with appearance, and quality of life for patients treated with conventional or virtual surgical planning; measures were high for both groups.

CONCLUSIONS

Conventional and virtual surgical planning of surgery-first bimaxillary orthognathic surgery resulted in quantitative and qualitative improvements in facial symmetry. Although patient satisfaction was similar for both approaches, virtual surgical planning was superior to conventional surgical planning for the improvement of midline and overall asymmetry.

CLINICAL RELEVANCE

Improvements with virtual surgical planning in facial midline, facial contour, and overall facial symmetry are as good as or better than conventional surgical planning.

An In Vivo Evaluation of Biocompatibility and Implant Accuracy of the Electron Beam Melting and Commercial Reconstruction Plates

The use of additive manufacturing in medical applications has become more prevalent over the last decade. Studies have proved that reconstruction plates with a mesh structure enhance the biocompatibility and bone-ingrowth formation. However, limited studies have been reported in the customization and in vivo clinical assessment of mesh implants. The purpose of this study was to investigate the surgical treatment and implant fitting accuracy using three different reconstruction plates. Fifteen goats were divided into one control and three experimental groups (Groups 1, 2, and 3) with five in each group. An experimental segmental defect was created on these animals and was adopted with customized electron beam melting reconstruction titanium plates with mesh in Group 1 and without mesh in Group 2 and commercial reconstruction plate in Group 3. All the animals were subjected to radiographic analysis before and after surgery. The subjected animals were sacrificed after 3 months and the electron beam melting reconstruction plates were compared with the commercial plate based on clinical and histology analysis and implant fitting accuracy. Both the electron beam melting reconstruction plates (with mesh and without mesh) and commercial plates survived the three months post-operation, revealing good wound-healing with new bone formation and without any foreign-body reaction. The electron beam melting reconstructed plate with mesh (Group 1) was found to have a better implant fitting when compared to the other two groups. The average discrepancy between Groups 2 and 3 was not significant. Certainly, the commercial plate (Group 3) was found to have the least accuracy as compared to other electron beam melting reconstruction plates (Group 1 and Group 2). Custom design electron beam melting fabricated reconstruction plates possessed better functionality, aesthetic outcome, and long-term biocompatibility when compared to commercial plates. Animal results indicated that the electron beam melting plates with mesh (Group 1) were superior in comparison to the other two groups due to its ability to provide better bone-in-growth and osseointegration on its porous microstructure.

Three-Dimensional Outcome Assessments of Cleft Lip and Palate Patients Undergoing Maxillary Advancement

BACKGROUND

The aim of this retrospective case series study was to compare three-dimensional postsurgical outcomes of patients with cleft lip and palate following maxillary advancement.

METHODS

Fifty consecutive cleft lip and palate patients who underwent whole-pieced Le Fort I advancements were assigned to the major (advancement ≥ 5 mm) or minor (advancement < 5 mm) groups. Three-dimensional surgical simulation was used for presurgical evaluation and planning. Virtual triangles of the presurgical, simulated, and 6-month postoperative stages were used for comparison. Translational and angular changes of each endpoint (A-point, MxR, and MxL) on the virtual triangles and reference planes were recorded and analyzed. Relationships between possible related variables and outcome discrepancies from simulations among all subgroups were also investigated.

RESULTS

Analysis of covariance and the least significant difference test revealed that the outcome discrepancy measurements were affected by different combinations of independent variables. The reliability test showed high consistency of the authors' method for three-dimensional measurements.

CONCLUSIONS

The actual surgical outcomes of cleft lip and palate patients differed from the virtual simulations. The outcome discrepancies are impacted by multiple factors. The outcome discrepancies of all rotational surgical corrections (roll, yaw, and pitch) were positively correlated to the degree of planned surgical movement. Meanwhile, bilateral cleft lip and palate patients are more likely to incur outcome discrepancies in yaw correction with major maxillary advancement. However, a maxillary advancement cutoff value of 5 mm would not necessarily lead to significant translational outcome discrepancies among cleft lip and palate patients.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

The Use of Virtual Surgical-Guided Osteoplasty for Maxillofacial Brown Tumors

A 28-year-old African American female with end-stage renal disease on dialysis secondary to preeclampsia presented to the office as a referral for large multifocal tumors of maxilla and mandible. Surgical pathology and laboratory findings were supportive of secondary hyperparathyroidism leading to multifocal brown tumors. She underwent osteoplasty after using virtual surgical planning to create stereolithic models to visualize the tumor and fabricate cutting guides to minimize the risk of injury to adjacent nerves and teeth. Brown tumors can be resistant to medical management with unreliable regression in size. With the advent of customized surgical guides, more precise and judicious surgery can be performed on these types of tumors safely.

The accuracy and stability of the maxillary position after orthognathic surgery using a novel computer-aided surgical simulation system

Background

Many reports have been published on orthognathic surgery (OGS) using computer-aided surgical simulation (CASS). The purpose of this study was to evaluate the accuracy of the maxillary repositioning and the stability of the maxilla in patients who underwent OGS using a newly developed CASS program, a customized osteotomy guide, and a customized miniplate.

Methods

Thirteen patients who underwent OGS from 2015 to 2017 were included. All patients underwent a bimaxillary operation. First, a skull-dentition hybrid 3D image was rendered by merging the cone beam computed tomography (CBCT) images with the dentition scan file. After virtual surgery (VS) using the FaceGide® program, patient-customized osteotomy guides and miniplates were then fabricated and used in the actual operation. To compare the VS with the actual surgery and postoperative skeletal changes, each reference point marked on the image was compared before the operation (T0) and three days (T1), four months (T2), and a year (T3) after the operation, and with the VS (Tv). The differences between ΔTv (Tv-T0) and ΔT1 (T1-T0) were statistically compared using tooth-based reference points. The superimposed images of Tv and T1 were also investigated at eight bone-based reference points. The differences between the reference points of the bone surface were examined to evaluate the stability of the miniplate on the maxilla over time.

Results

None of the patients experienced complications. There were no significant differences between the reference points based on the cusp tip between ΔTv and ΔT1 (p > 0.01). Additionally, there were no significant differences between the Tv and T1 values of the bone surface (p > 0.01). The mean difference in the bone surface between Tv and T1 was 1.01 ± 0.3 mm. Regarding the stability of the miniplate, there were no significant differences between the groups. The difference in the bone surface between T1 and T3 was − 0.37 ± 0.29 mm.

Conclusions

VS was performed using the FaceGide® program, and customized materials produced based on the VS were applied in actual OGS. The maxilla was repositioned in almost the same manner as in the VSP plan, and the maxillary position remained stable for a year.

Developing an In-house Interdisciplinary Three-Dimensional Service: Challenges, Benefits, and Innovative Health Care Solutions

Three-dimensional printing (3DP) technologies have been employed in regular medical specialties. They span wide scope of uses, from creating 3D medical models to design and manufacture of Patient-specific implants and guidance devices which help to optimize medical treatments, patient education, and medical training. This article aims to provide an in-depth analysis of factors and aspects to consider when planning to setup a 3D service within a hospital serving various medical specialties. It will also describe challenges that might affect 3D service development and sustainability and describe representative cases that highlight some of the innovative approaches that are possible with 3D technology. Several companies can offer such 3DP service. They are often web based, time consuming, and requiring special call conference arrangements. Conversely, the establishment of in-house specialized hospital-based 3D services reduces the risks to personal information, while facilitating the development of local expertise in this technology. The establishment of a 3D facility requires careful consideration of multiple factors to enable the successful integration with existing services. These can be categorized under: planning, developing and sustaining 3D service; 3D service resources and networking workflow; resources and location; and 3D services quality and regulation management.

Using Black Bone Magnetic Resonance Imaging in Craniofacial Virtual Surgical Planning: A Comparative Cadaver Study

BACKGROUND

The use of magnetic resonance imaging (MRI) for virtual surgical planning has not yet been described. In the United States, over 600,000 computed tomographic (CT) scans are performed annually on children, who are at higher risk than adults of developing cancer caused by ionizing radiation. The aim of this study was to demonstrate whether three-dimensionally-printed craniofacial surgical guides created from "black bone" MRI are comparable in accuracy to those created from CT scans.

METHODS

A mock craniosynostosis surgery translocating four calvarial segments was virtually planned and performed in 10 cadavers. For five specimens, planning was performed and three-dimensionally-printed guides were created using black bone MRI scans. Five specimens underwent standard planning using CT scans. Reconstructed skulls underwent CT scans and three-dimensional reconstruction. Accuracy was compared to that of virtually planned surgeries.

RESULTS

The preoperative black bone MRI scan had an average deviation from the preoperative CT scan of 1.37 mm. There was no statistically significant difference in the fit accuracy of MRI versus CT-created guides. Average deviation of postoperative anatomy from preoperative plan was within 1.5 mm for guides created from either scanning modality, with no statistically significant difference in accuracy between the two methods. Planned versus postoperative skull volume was not statistically significantly different when MRI versus CT was used.

CONCLUSIONS

This study demonstrates that virtual surgical planning and three-dimensional craniofacial surgical guide creation can be performed using black bone MRI with accuracy comparable to that of CT. This could dramatically reduce radiation exposure of craniofacial reconstruction patients.

A New Software Suite in Orthognathic Surgery : Patient Specific Modeling, Simulation and Navigation

Orthognathic surgery belongs to the scope of maxillofacial surgery. It treats dentofacial deformities consisting in discrepancy between the facial bones (upper and lower jaws). Such impairment affects chewing, talking, and breathing and can ultimately result in the loss of teeth. Orthognathic surgery restores facial harmony and dental occlusion through bone cutting, repositioning, and fixation. However, in routine practice, we face the limitations of conventional tools and the lack of intraoperative assistance. These limitations occur at every step of the surgical workflow: preoperative planning, simulation, and intraoperative navigation. The aim of this research was to provide novel tools to improve simulation and navigation. We first developed a semiautomated segmentation pipeline allowing accurate and time-efficient patient-specific 3D modeling from computed tomography scans mandatory to achieve surgical planning. This step allowed an improvement of processing time by a factor of 6 compared with interactive segmentation, with a 1.5-mm distance error. Next, we developed a software to simulate the postoperative outcome on facial soft tissues. Volume meshes were processed from segmented DICOM images, and the Bullet open source mechanical engine was used together with a mass-spring model to reach a postoperative simulation accuracy <1 mm. Our toolset was completed by the development of a real-time navigation system using minimally invasive electromagnetic sensors. This navigation system featured a novel user-friendly interface based on augmented virtuality that improved surgical accuracy and operative time especially for trainee surgeons, therefore demonstrating its educational benefits. The resulting software suite could enhance operative accuracy and surgeon education for improved patient care.

The accuracy of virtual-surgical-planning-assisted treatment of hemifacial microsomia in adult patients: distraction osteogenesis vs. orthognathic surgery

Hemifacial microsomia (HFM) is a common congenital craniofacial deformity with a high prevalence. Orthognathic surgery and distraction osteogenesis are two conventionally used treatments of HFM. The main objective of this retrospective study was to evaluate the accuracy of two treatments with the help of virtual surgical planning in adult HFM patients. Sixty-eight adult patients with unilateral HFM were enrolled in this study. Preoperative surgical planning and simulation were performed on three-dimensional computed tomography models. Orthognathic surgery or distraction osteogenesis was performed under the guidance of three-dimensional surgical templates. Postoperative evaluation of the intervention was performed by comparison of the affected ramus height, chin deviation and the occlusal cant in surgical planning and actual result. Outcome and feedback information (an average of 14 months) showed that virtual surgical planning was accurately transferred to actual surgery in both surgical approaches. There were no statistical differences between the accuracy of affected ramus height and the occlusal cant in two surgical approaches. The orthognathic group showed significantly higher accuracy in chin deviation. In conclusion, virtual surgical planning and three-dimensional surgical templates were proved to facilitate treatment planning and offer an accurate surgical result in the treatment of adult HFM patients.

Virtual Surgical Planning Assisted Management for Three-Dimensional Dentomaxillofacial Deformities

OBJECTIVE

Treatment of 3-dimensional dentomaxillofacial deformities remains a significant clinical challenge. This retrospective study aims to present the modalities of management for complex 3-dimensional dentomaxillofacial deformities with the assistance of virtual surgical planning (VSP) and 3-dimensional printed navigation templates.

STUDY DESIGN

Ten patients diagnosed with complex 3-dimensional dentomaxillofacial deformities received treatment of combined orthodontics and orthognathic surgery. Various surgical techniques as well as bone graft and distraction osteogenesis were used under the guidance of VSP and 3-dimensional printed navigation templates according to the characteristics of each patient. Follow-up included clinical examination and studies of spiral computed tomography preoperatively and for an average of 12 months postoperatively.

RESULT

The clinical outcomes of patients showed that VSP was successfully transferred to actual surgery in all the 10 patients. Three-dimensional dentomaxillofacial deformities were corrected significantly. Satisfactory profiles and occlusion were achieved.

CONCLUSION

The management of 3-dimensional dentomaxillofacial deformities required comprehensive consideration and detailed surgical planning. Virtual surgical planning serves as a reliable assistance in the management of 3-dimensional dentomaxillofacial deformities.

Does two-dimensional vs. three-dimensional surgical simulation produce better surgical outcomes among patients with class III facial asymmetry?

The aim of this study was to compare the outcomes of traditional two-dimensional planning (2DP) and three-dimensional surgical simulation (3DS) in the surgical correction of skeletal class III with facial asymmetry. This retrospective cohort study included 37 consecutive adult Taiwanese patients. Preoperative and postoperative three-dimensional cephalometric measurements were obtained from cone beam computed tomography scans. The outcome variables were the differences in preoperative and postoperative linear and angular measurements and the differences between the two groups after surgery. When the surgical result was compared between the 2DP and 3DS groups, significant differences were found for four cephalometric variables: the distance from gonion on the non-deviated side to the midsagittal plane (MSP), mid-gonion to the MSP, upper first molar on the non-deviated side to the Frankfort horizontal plane, and the yaw angle. In the 3DS group, mandibular symmetry was achieved because the centre between the bilateral gonions was improved, and because there was no significant difference in the horizontal gonion (Go to the MSP) between the deviated and non-deviated sides after surgery. 3DS provides all the necessary information for planned surgical movements for the correction of facial asymmetry; it should be considered during surgical planning to improve surgical outcomes, particularly the achievement of bilateral mandibular contour symmetry.

Improved Virtual Planning for Bimaxillary Orthognathic Surgery

Conventional model surgery planning for bimaxillary orthognathic surgery can be laborious, time-consuming and may contain potential errors; hence three-dimensional (3D) virtual orthognathic planning has been proven to be an efficient, reliable, and cost-effective alternative. In this report, the 3D planning is described for a patient presenting with a Class III incisor relationship on a Skeletal III base with pan facial asymmetry complicated by reverse overjet and anterior open bite. A combined scan data of direct cone beam computer tomography and indirect dental scan were used in the planning. Additionally, a new method of establishing optimum intercuspation by scanning dental casts in final occlusion and positioning it to the composite-scans model was shown. Furthermore, conventional model surgery planning was carried out following in-house protocol. Intermediate and final intermaxillary splints were produced following the conventional method and 3D printing. Three-dimensional planning showed great accuracy and treatment outcome and reduced laboratory time in comparison with the conventional method. Establishing the final dental occlusion on casts and integrating it in final 3D planning enabled us to achieve the best possible intercuspation.

Virtual surgical planning and 3D printing in repeat calvarial vault reconstruction for craniosynostosis: technical note

Repeat surgery for restenosis after initial nonsyndromic craniosynostosis intervention is sometimes needed. Calvarial vault reconstruction through a healed surgical bed adds a level of intraoperative complexity and may benefit from preoperative and intraoperative definitions of biometric and aesthetic norms. Computer-assisted design and manufacturing using 3D imaging allows the precise formulation of operative plans in anticipation of surgical intervention. 3D printing turns virtual plans into anatomical replicas, templates, or customized implants by using a variety of materials. The authors present a technical note illustrating the use of this technology: a repeat calvarial vault reconstruction that was planned and executed using computer-assisted design and 3D printed intraoperative guides.

Zygomatico-maxillary Reconstruction with Computer-aided Manufacturing of a Free DCIA Osseous Flap and Intraoral Anastomoses

Craniomaxillofacial reconstruction using virtual surgical planning, computer-aided manufacturing, and new microsurgical techniques optimizes patient-specific and defect-directed reconstruction. A 3D customized free deep circumflex iliac artery (DCIA) flap with intraoral anastomoses was performed on a 23-year-old man with a posttraumatic right zygomatico-maxillary defect with failure of alloplastic implant reconstruction. An osseous iliac crest flap was sculpted based on a customized 3D model of the mirror image of the patient's unaffected side to allow for perfect fit to the zygomatico-maxillary defect. An intraoral dissection of the facial artery and vein was performed within the right cheek mucosa and allowed for end-to-end microvascular anastomoses. 3D preoperative planning and customized free DCIA osseous flap combined with an intraoral microsurgical technique provided restoration of facial esthetics and function without visible scars. In cases where zygomatico-malar reconstruction by alloplastic material fails, a customized free DCIA osseous flap can be designed by virtual surgical planning to restore facial appearance and function.

Testing the Construct Validity of a Virtual Reality Hip Arthroscopy Simulator

PURPOSE

To test the construct validity of the hip diagnostics module of a virtual reality hip arthroscopy simulator.

METHODS

Nineteen orthopaedic surgeons performed a simulated arthroscopic examination of a healthy hip joint using a 70° arthroscope in the supine position. Surgeons were categorized as either expert (those who had performed 250 hip arthroscopies or more) or novice (those who had performed fewer than this). Twenty-one specific targets were visualized within the central and peripheral compartments; 9 via the anterior portal, 9 via the anterolateral portal, and 3 via the posterolateral portal. This was immediately followed by a task testing basic probe examination of the joint in which a series of 8 targets were probed via the anterolateral portal. During the tasks, the surgeon's performance was evaluated by the simulator using a set of predefined metrics including task duration, number of soft tissue and bone collisions, and distance travelled by instruments. No repeat attempts at the tasks were permitted. Construct validity was then evaluated by comparing novice and expert group performance metrics over the 2 tasks using the Mann-Whitney test, with a P value of less than .05 considered significant.

RESULTS

On the visualization task, the expert group outperformed the novice group on time taken (P = .0003), number of collisions with soft tissue (P = .001), number of collisions with bone (P = .002), and distance travelled by the arthroscope (P = .02). On the probe examination, the 2 groups differed only in the time taken to complete the task (P = .025) with no significant difference in other metrics.

CONCLUSIONS

Increased experience in hip arthroscopy was reflected by significantly better performance on the virtual reality simulator across 2 tasks, supporting its construct validity.

CLINICAL RELEVANCE

This study validates a virtual reality hip arthroscopy simulator and supports its potential for developing basic arthroscopic skills.

LEVEL OF EVIDENCE

Level III.

Using 3D computer planning for complex reconstruction of mandibular defects

For complex reconstruction of osseous defects of the head and neck, three-dimensional (3D) computer planning has been available for over 20 years. However, despite its availability and recent refinements, it is a technology that has not been widely adopted. While 3D computer planning has been proposed to improve surgical precision, reduce operating time and enhance functional outcomes, the objective evidence supporting these claims is limited. Here we review the recent literature that supports the use of 3D computer planning for complex osseous defects of the mandible. We highlight a case example where 3D modeling played a critical role, particularly during the virtual surgical planning stage. Finally, we propose that routine post-operative 3D analysis become an essential element in determining operative success. Critical evaluation of outcomes will better define its use in complex reconstruction of osseous defects.

Economic evaluation of diagnostic methods used in dentistry. A systematic review

OBJECTIVES

To review the literature of economic evaluations regarding diagnostic methods used in dentistry.

DATA SOURCES

Four databases (MEDLINE, Web of Science, The Cochrane library, the NHS Economic Evaluation Database) were searched for studies, complemented by hand search, until February 2013.

STUDY SELECTION

Two authors independently screened all titles or abstracts and then applied inclusion and exclusion criteria to select full-text publications published in English, which reported an economic evaluation comparing at least two alternative methods. Studies of diagnostic methods were assessed by four reviewers using a protocol based on the QUADAS tool regarding diagnostic methods and a check-list for economic evaluations. The results of the data extraction were summarized in a structured table and as a narrative description.

RESULTS

From 476 identified full-text publications, 160 were considered to be economic evaluations. Only 12 studies (7%) were on diagnostic methods, whilst 78 studies (49%) were on prevention and 70 (40%) on treatment. Among studies on diagnostic methods, there was between-study heterogeneity methodologically, regarding the diagnostic method analysed and type of economic evaluation addressed. Generally, the choice of economic evaluation method was not justified and the perspective of the study not stated. Costing of diagnostic methods varied.

CONCLUSIONS

A small body of literature addresses economic evaluation of diagnostic methods in dentistry. Thus, there is a need for studies from various perspectives with well defined research questions and measures of the cost and effectiveness.

CLINICAL SIGNIFICANCE

Economic resources in healthcare are finite. For diagnostic methods, an understanding of efficacy provides only part of the information needed for evidence-based practice. This study highlighted a paucity of economic evaluations of diagnostic methods used in dentistry, indicating that much of what we practise lacks sufficient evidence.