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Virtual surgical planning is the process of planning and rehearsing a surgical procedure completely within the virtual environment on computer models. Virtual surgical planning and 3D printing is gaining popularity in veterinary oromaxillofacial surgery and are viable tools for the most basic to the most complex cases. These techniques can provide the surgeon with improved visualization and, thus, understanding of the patients' 3D anatomy. Virtual surgical planning is feasible in a clinical setting and may decrease surgical time and increase surgical accuracy. For example, pre-operative implant contouring on a 3D-printed model can save time during surgery; 3D-printed patient-specific implants and surgical guides help maintain normocclusion after mandibular reconstruction; and the presence of a haptic model in the operating room can improve surgical precision and safety. However, significant time and financial resources may need to be allocated for planning and production of surgical guides and implants. The objectives of this manuscript are to provide a description of the methods involved in virtual surgical planning and 3D printing as they apply to veterinary oromaxillofacial surgery and to highlight these concepts with the strategic use of examples. In addition, the advantages and disadvantages of the methods as well as the required software and equipment will be discussed.

3D object printing technology is a resource increasingly used in medicine in recent years, mainly incorporated in surgical areas like orthopedics. The models made by 3D printing technology provide surgeons with an accurate analysis of complex anatomical structures, allowing the planning, training, and surgery simulation. In orthopedic surgery, this technique is especially applied in oncological surgeries, bone, and joint reconstructions, and orthopedic trauma surgeries. In these cases, it is possible to prototype anatomical models for surgical planning, simulating, and training, besides printing of instruments and implants. The purpose of this paper is to describe the acquisition and processing from computed tomography images for 3D printing, to describe modeling and the 3D printing process of the biomodels in real size. This paper highlights 3D printing with the applicability of the 3D biomodels in orthopedic surgeries and shows some examples of surgical planning in orthopedic trauma surgery. Four examples were selected to demonstrate the workflow and rationale throughout the process of planning and printing 3D models to be used in a variety of situations in orthopedic trauma surgeries. In all cases, the use of 3D modeling has impacted and improved the final treatment strategy. The use of the virtual anatomical model and the 3D printed anatomical model with the additive manufacturing technology proved to be effective and useful in planning and performing the surgical treatment of complex articular fractures, allowing surgical planning both virtual and with the 3D printed anatomical model, besides being useful during the surgical time as a navigation instrument.

Background: Technological progress has led to the transition to digital methods to perform surgical planning and to obtain surgical splints with CAD/CAM technologies. The present study aimed to compare the accuracy of jaw repositioning in bimaxillary orthognathic surgery using traditional and digital surgical planning in skeletal class III patients. Methods: This study included 60 skeletal class III patients divided into two groups based on the method used to perform surgical planning: traditional (T, n = 30) and digital (D, n = 30). For each patient, a 2D presurgical Visual Treatment Objective (VTO) was prepared and the outcome of the surgery was compared with that planned by using determined cephalometric measurements (ANB, SNA, SNB, Ar-Go-Me, S-Ar-Go). Statistical analysis showed that the measurements planned and those obtained after surgery were equivalent in Group D. For Group T, the analysis showed equivalence only for one of the considered measurements (ANB). By comparing the results of the two groups, Group D presented a lower level of error than Group T. Conclusions: Digital surgical planning performed significantly better in terms of accuracy of jaw repositioning than the traditional protocol.

  Purpose Three-dimensional surgical planning (3-DSP) is becoming commonplace in the management of benign and malignant disease for oral and maxillofacial surgery practice within the last decade. Surgeons utilize a virtual “wrap” to preoperatively delineate and define maxillofacial tumor resection margins. The investigators hypothesized that the use of a wrap is a predictable method to obtain negative bony margins. Methods The investigators implemented a retrospective chart review. The sample was composed of patients over the age of 18 treated at John Peter Smith Health Network and Parkland/UT Southwestern Medical Center who obtained 3-DSP for the pathology of the head and neck, involving the bone, with a virtual wrap utilized for bony margins. The proportion of cases was calculated, descriptive statistics were reported, and binomial exact calculation was performed for confidence intervals. The primary variable analyzed was bony margin status on final histopathology, involved or uninvolved, based on the pathology report. Results The sample was composed of 39 cases, one of which was excluded due to aborting the preplanned 3-DSP. Of the 38 included cases, one had involved bony margin on final histopathology (2.6%; 95% confidence limits, 0.1%, 13.8%). There were 16 malignant cases (42%) and 22 benign cases (58%). When stratified by pathology, 1 out of the 16 malignant cases (6.3%; 95% confidence interval, 0.2%, 30%) and 0 out of the 22 benign cases (95% confidence interval, 0%, 15.4%) had an involved bony margin on final histopathology. Conclusion The results of this preliminary study suggest three-dimensional surgical planning with wrap margins is a predictable method to obtain negative bony margins in benign and malignant disease of the maxillofacial complex. Further studies will focus on compiling prospective data to solidify the accuracy and predictability of using a wrap to obtain negative bony margins.

Background and Aim The accuracy of the virtually-designed 3D-printed surgical splints requires investigation for the practical use of surgical plan in the operating room. This study aimed to compare the validity of the 3D-printed and the conventional intermediate splints and evaluate the outcomes after the surgical application of the 3D-printed splint compared with the predicted values. Methods In this study, ten patients with dentofacial deformity were recruited. Participants were analyzed by the conventional surgical planning and virtual surgical planning. The intermediate surgical splints were created by the conventional and 3D-printing methods. Maxillary movements in 3 spatial directions were measured in an articulator after the application of both splints. Correlation and agreement between the two methods were tested by intraclass correlation coefficient (ICC). After the confirmation of 3D printed splint validity for each patient, the surgery was performed using 3D printed splints. It is assumed that ideally cephalometric prediction values are going to be obtained using conventional acrylic splints (gold standard). So, as a second objective, the outcome of the surgically-applied 3D-printed splint was evaluated and compared with the predicted values and finally analyzed by the paired t-test. Results Based on the observations, there was an excellent agreement between the virtually-designed 3D-printed and conventional intermediate surgical splints (ICC ranged between 0.83 and 0.99 for linear values). There was a good cumulative agreement of ICC greater than 0.80. Overall, the mean linear measurements were not different between conventional and 3D-printed splint on the articulator. Also, there were no significant differences between the linear and angular measurements of 2D-cephalometric prediction and postoperation values. Conclusion The results showed cautiously the acceptable accuracy of the 3D-printed splints for several parameters in three spatial dimensions within the laboratory and clinical settings.

Background and Objectives: In the field of orthopedic surgery, novel techniques of three-dimensional shape modeling using two-dimensional tomographic images are used for bone-shape measurements, preoperative planning in joint-replacement surgery, and postoperative evaluation. ZedView® (three-dimensional measurement instrument and preoperative-planning software) had previously been developed. Our group is also using ZedView® for preoperative planning and postoperative evaluation for more accurate implant placement and osteotomy. This study aimed to evaluate the measurement error in this software in comparison to a three-dimensional measuring instrument (3DMI) using human bones. Materials and Methods: The study was conducted using three bones from cadavers: the pelvic bone, femur, and tibia. Three markers were attached to each bone. Study 1: The bones with markers were fixed on the 3DMI. For each bone, the coordinates of the center point of the markers were measured, and the distances and angles between these three points were calculated and defined as “true values.” Study 2: The posterior surface of the femur was placed face down on the 3DMI, and the distances from the table to the center of each marker were measured and defined as “true values.” In each study, the same bone was imaged using computed tomography, measured with this software, and the measurement error from the corresponding “true values” was calculated. Results: Study 1: The mean diameter of the same marker using the 3DMI was 23.951 ± 0.055 mm. Comparisons between measurements using the 3DMI and this software revealed that the mean error in length was <0.3 mm, and the error in angle was <0.25°. Study 2: In the bones adjusted to the retrocondylar plane with the 3DMI and this software, the average error in the distance from the planes to each marker was 0.43 (0.32–0.58) mm. Conclusion: This surgical planning software could measure the distance and angle between the centers of the markers with high accuracy; therefore, this is very useful for pre- and postoperative evaluation.

Background The purpose of this study was to measure the time of the conventional surgical planning (CSP) and virtual surgical planning (VSP) in orthognathic surgery and to compare them in terms of cost. Material and method This is a retrospective study of the patients who underwent orthognathic surgery at the OOOOO University Dental Hospital from December 2017 to August 2018. All the patients were analyzed through both CSP and VSP, and all the surgical stents were fabricated through manual and 3-dimensional (3D) printing. The predictor variables were the planning method (CSP vs. VSP) and the surgery type (group I: Le Fort I osteotomy+bilateral sagittal split osteotomy [LFI+BSSO] or group II: only bilateral sagittal split osteotomy [BSSO]), and the outcomes were the time and cost. The results were analyzed using paired t test. Results Thirty patients (12 females, 18 males) met the inclusion criteria, and 17 patients were excluded from the study due to missing or incomplete data. There were 20 group I patients (LFI+BSSO regardless of genioplasty) and 10 group II patients (BSSO regardless of genioplasty). The average time of CSP for group I was 385±7.8 min, and that for group II was 195±8.33 min. The time reduction rate of VSP compared with CSP was 62.8% in group I and 41.5% in group II. On the other hand, there was no statistically significant cost reduction. Conclusions The time investment in VSP in this study was significantly smaller than that in CSP, and the difference was greater in group I than in group II.

Background The purpose of this study was to measure the time of the conventional surgical planning (CSP) and virtual surgical planning (VSP) in orthognathic surgery and to compare them in terms of cost. Material and method This is a retrospective study of the patients who underwent orthognathic surgery at the Pusan National University Dental Hospital from December 2017 to August 2018. All the patients were analyzed through both CSP and VSP, and all the surgical stents were fabricated through manual and three-dimensional (3D) printing. The predictor variables were the planning method (CSP vs. VSP) and the surgery type (group I: Le Fort I osteotomy + bilateral sagittal split osteotomy [LFI+BSSO] or group II: only bilateral sagittal split osteotomy [BSSO]), and the outcomes were the time and cost. The results were analyzed using the paired t test. Results Thirty patients (12 females, 18 males) met the inclusion criteria, and 17 patients were excluded from the study due to missing or incomplete data. There were 20 group I patients (LFI+BSSO regardless of genioplasty) and 10 group II patients (BSSO regardless of genioplasty). The average time of CSP for group I was 385 ± 7.8 min, and that for group II was 195 ± 8.33 min. The time reduction rate of VSP compared with CSP was 62.8% in group I and 41.5% in group II. On the other hand, there was no statistically significant cost reduction. Conclusions The time investment in VSP in this study was significantly smaller than that in CSP, and the difference was greater in group I than in group II.

Objectives The purpose of this study was to compare the accuracy of hard tissues movements planned to result of the maxillary and mandibular positions between conventional surgical planning (CSP) and virtual surgical planning (VSP) in patients undergoing orthognathic surgery. Methods A systematic electronic search was carried out in six databases and gray literature with no restriction of publication date and language. Clinical observational studies that compared accuracy of maxillary position between CSP and VSP were included. Linear measurements of the mandible in the transverse plane and linear measurements of the maxilla in the vertical, horizontal and transverse planes were considered for analysis, comparing planned to postoperative outcomes of CSP and VSP. Cochrane tool was used to assess bias risk. A meta-analysis was performed to summarize similar results by using the Review Manager 5.3 software. Significance level was set at 5%. Results Six studies (2 RCT and 4 retrospective cohorts) were included according to inclusion and eligibility criteria, involving 255 patients. The inter-rater reliability of selection and eligibility was excellent ( k  = 0.8315 and k  = 0.9329, respectively). Two studies presented that VSP seemed to have better results than CSP regarding linear measurements of the mandible in the transverse plane. Results from CSP and VSP were similar in accuracy for hard tissue in vertical plane of maxillary position ( I 2  = 0%; p  = 0.17), although VSP was more accurate in horizontal plane ( I 2  = 0%; p  = 0.02). Conclusion VSP presented better accuracy for transverse movements in mandible of asymmetric patients. VSP showed to be more accurate for movements in the horizontal plane, and qualitative analysis seemed to be more effective for transverse movements.

Background Increased implant number is thought to provide better control on the scoliotic spine, but there is limited scientific evidence of improved deformity correction and surgical outcomes with high-density constructs. The objective is to assess key anchor points used by experienced spinal deformity surgeons and to evaluate the effect of implant density pattern on correction techniques. Methods Seventeen experienced spine surgeons reviewed five Lenke 1 adolescent idiopathic scoliosis cases and provided their preferred posterior correction technique (implant pattern, correction maneuvers, and implants used for their execution) and an alternative technique with the minimal implant density they felt would be acceptable (170 surgical plans total). Additionally, for each case, they selected acceptable screw patterns for surgery from seven published implant configurations. Variability in the surgeons’ plans was assessed, including instrumentation and correction strategies. Results The preferred correction plan involved an average of 1.65 implants/vertebra, with 88% of the available anchor points at the apex ± 1 vertebra used for the execution of correction maneuvers and only 43% of possible anchor points used proximal and distal to the apical area. The minimal density that surgeons found acceptable was 1.24 implants/vertebra. The minimal density plan involved more in situ rod contouring (53 vs. 41%), fewer vertebral derotation maneuvers (82 vs. 96%), and fewer implants used for compression/distraction maneuvers (1.18 and 1.42 respectively) ( p  < 0.05). Implant placement at alternate levels or dropout of convex implants above and below the apical area was most frequently considered acceptable (> 70% agreement). Conclusions Implant position and number affect surgeons correction maneuvers selection. For low implant density constructs, dropout in the convexity and particularly in the periapical region is accepted by surgeons, with minor influence on planned correction maneuvers. Thus, preoperative implant planning must take into account which anchor points are needed for desired correction maneuvers.