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Obstructive sleep apnoea (OSA) is a syndrome with a high burden on public health. Maxillomandibular advancement (MMA) has proven to be a highly effective treatment option. This retrospective analysis evaluated the safety of maxillomandibular advancement with rotation in patients with OSA. A total of 63 patients with OSA were included in this study. Surgical treatment by maxillomandibular advancement was virtually planned based on preoperative cone beam computed tomography (CBCT). A 3D printed guide and a customised implant were used for surgical transfer. The safety of MMA was evaluated based on the necessity of postoperative intermediate care unit (IMCU) stay, duration of stay in hospital, and recording of medical complications. A total of 63.5% of the OSA patients treated by MMA (n = 40/63) were postoperatively transferred from the recovery room directly to the regular ward, while 36.5% of the patients (n = 23/63) stayed on IMCU for at least one night. On average, the length of hospitalisation was four days after surgery. One patient from the ward group and one patient from the IMCU group developed a major complication according to Clavian-Dindo classification grade IV. MMA is a safe surgical procedure. The necessity for postoperative monitoring in an IMCU setting should be based on an individual risk evaluation. However, since major complications can occur, MMA should be performed as an inpatient procedure in a hospital with available intensive medicine care. This study underlines the safety of MMA in OSA patients. [ABSTRACT FROM AUTHOR]

Virtual planning for shoulder arthroplasty using preoperative computed tomography (CT) has been gaining popularity, and it is imperative for surgeons to recognize any differences in measurements that may exist amongst software platforms. The purpose of this study is to compare measurements of glenoid version, inclination, and humeral head subluxation between a manual approach and two varying automated software platforms using either a best-fit sphere technique (Wright-Medical BLUEPRINT) or an anatomic landmarks technique (Materalise SurgiCase). A case control study of 289 CT images from patients preoperatively planned for a total shoulder arthroplasty or reverse shoulder arthroplasty using SurgiCase (v3.0.110.5) were also successfully analyzed by BLUEPRINT (v2.1.6). Glenoid version, inclination, and subluxation were measured manually in a blind fashion by two separate investigators using axial and coronal images oriented to the scapular plane; interobserver and intraobserver reliabilities were measured using intraclass correlation coefficients (ICCs). Concordance correlation coefficients (CCCs), mean differences, and clinically relevant agreement in measurements between the software platforms and with the manual technique were compared. The impact of greater glenoid retroversion on the differences in measurements between the software platforms was further studied by correlation analysis. The mean differences between SurgiCase and BLUEPRINT were + 0.5° for glenoid inclination (P =.064; CCC = 0.84), -0.9° for glenoid version (P <.001; CCC = 0.92), and -1.4% for humeral subluxation (P =.002; CCC = 0.88). Agreement within 5 units was 78.9% for inclination, 89.3% for version, and 64.1% for subluxation. Glenoid retroversion had no relation with the degree of variation in measured inclination (P =.59) or version (P =.56). There were significant differences between manual and 3D software measurements for glenoid inclination, version, and subluxation (P <.001). Both software measurements were more inferiorly inclined (average difference, SurgiCase -3.2° and BLUEPRINT -3.9°), more retroverted (average difference, SurgiCase -4.0° and BLUEPRINT -3.2°), and more posteriorly subluxated (average difference, SurgiCase + 3.4% and BLUEPRINT + 4.8%). The SurgiCase and BLUEPRINT preoperative planning software yield clinically similar measurements for glenoid version, inclination, and subluxation. The degree of glenoid retroversion does not impact the variability of inclination or version between the landmark and best-fit sphere software techniques. Compared to the 2D manual technique, both 3D software programs reported greater inferior inclination, retroversion, and posterior subluxation. Level III; Retrospective Diagnostic Study [ABSTRACT FROM AUTHOR]

This study compared two transferring methods for virtually planned orthognathic surgery — the CAD/CAM intermediate splint and the customized surgical guide with fixation plates. This was a prospective clinical study in which participants were consecutively recruited and underwent bimaxillary orthognathic surgery. They were divided into two groups based on the transferring method used. The pre- and postoperative CBCTs were aligned using voxel-based landmark-free registration, and the discrepancies for selected points were compared with the planned displacement of the virtually planned surgery. The maxilla and mandible were analyzed separately, and translation and rotation movements were considered. A total of 16 patients, divided into two groups of eight patients each, were included in this study. The splintless group was significantly more accurate for the translation movement along the x -axes for points A (p = 0.008; mean absolute error 0.527 ± 0.387 for the splint group and 0.137 ± 0.067 for the splintless group) and Ans (p = 0.045; mean absolute error 0.535 ± 0.446 for the splint group and 0.156 ± 0.002 for the splintless group). For the mandible there was a significant difference in accuracy along the x -axes for points B (p = 0.049; mean absolute errors 1.728 ± 1.181 and 0.697 ± 0.519 for the splint and splintless groups, respectively), LL3 (p = 0.049; mean absolute error 1.629 ± 0.912 and 0.851 ± 0.797 for the splint and splintless groups, respectively), LR3 (p = 0.049; mean absolute error 1.711 ± 0.906 and 0.844 ± 0.780 for the splint and splintless groups, respectively), with the splintless group being more accurate. For the rotation the splintless group was significantly more accurate along the y -axes (p = 0.04; mean absolute error 1.62 ± 0.78 and 0.49 ± 0.31 for the splint and splintless groups, respectively) and z -axes (p = 0.04; mean absolute error 0.63 ± 0.45 and 0.17 ± 0.05 for the splint and splintless groups, respectively) for the maxilla, while no significant difference was found for the mandible. Overall, the customized fixation plate system is more accurate than the intermediate CAD/CAM splint for transferring the virtual plan into the operation room. [ABSTRACT FROM AUTHOR]

In the past few years, virtual planning has been increasingly used for mandibular reconstruction. The objective of our study was to evaluate and compare symmetry and the accuracy of morphologic reconstruction in patients undergoing mandibular reconstruction by fibular free flap between traditional freehand technique and computer-aided surgical cutting guides. A single-center retrospective study included all cases of mandibular reconstruction using fibular free flap. In the three-dimensional (3D) group, virtual surgery planning with cut guides was used (Materialise ®), while the Control group underwent traditional freehand reconstruction. Morphometric comparisons were made to evaluate reconstruction accuracy between pre- and post-operative CT scans (mean deviations of 3 angles and 3 lengths). Mandible symmetry was calculated by comparing each angle and length in the affected and non-affected sides of the mandible. Thirty-three patients treated between January 2015 and June 2018 were included: 25 patients in the 3D group and 8 in the control group. The average number of mandibular segments was 2.16 ± 0.55 in the 3D group and 1.75 ± 1.16 in the control group (p = 0.005). Mean deviations between pre- and post-operative values of the coronal mandibular angle (angle formed by the line through the two condyles and the ramus), mandibular body height and mandibular ramus length on the affected side were significantly lower in the 3D group than in the control group. Sagittal mandibular angle symmetry was better in the 3D group than, in the control group (ratios of affected over non-affected sides: 1.07 ± 0.04 vs 1.12 ± 0.1; p = 0.034). Virtual surgical planning for fibula free-flap reconstruction helps to improve reconstruction accuracy and maintains a significantly greater symmetry than the traditional freehand technique, and should improve functional and esthetic outcome in mandibular reconstruction. [ABSTRACT FROM AUTHOR]

Digital technology has been progressively introduced into tooth autotransplantation to enhance both treatment planning and surgery. The aim of this report was to describe a novel protocol for fully guided tooth autotransplantation. This report includes 10 consecutive patients treated with a complete virtual planning and a multidrilling axis surgical guide in combination with the computer-aided rapid prototyping model. All transplanted teeth fulfilled the criteria for success over a mean follow-up duration of 13.1 months. No signs of progressive root resorption or pain were found during follow-up. One case required minimal adjustment of the surgical stent to allow correct seating, whereas a second case could not be performed fully guided because of limited mouth opening. Our protocol for fully guided tooth autotransplantation is a viable option that involves minimal bone preparation in a short surgical time. Future research should focus on further investigation of the benefits of this novel protocol in a larger sample. [ABSTRACT FROM AUTHOR]

After sagittal split osteotomy, the mandibular distal and proximal fragments do not always align themselves passively to one another, resulting in bony interferences and subsequent anomalous settlement of the condyles. Predicting these interferences could be an important ancillary procedure for avoiding intra- and postoperative surgical complications, rendering orthognathic surgery more effective and safer. This study evaluated the relevance of virtual surgical planning in assessing the displacement of the proximal segments after virtual distal segment repositioning, for predicting bony interferences between the segments and thus avoiding related intra- and postoperative surgical complications. The presence of interferences between the distal and proximal segments was compared between virtually predicted (computer-assisted simulation surgery, Dolphin software) and real cases in 100 consecutive patients diagnosed with dentofacial deformities who underwent orthognathic surgery with mandibular repositioning (using a short lingual osteotomy (SLO)). The results indicated that clockwise rotation of the mandible was the mandibular movement most prone to segment interference. Furthermore, virtual planning was sensitive (100%) but had low specificity (51.6%) in predicting proximal and distal segment interferences. This low specificity was due to the software-based automated design of the mandibular osteotomy, where the length of the distal segment was longer than the real SLO, and the mandibular ramus sagittal split was located just behind Spix's spine. Thus, more precise simulated osteotomies are needed to further validate the accuracy of virtual planning for this purpose. [ABSTRACT FROM AUTHOR]

To assess the accuracy of laser-melted patient-specific implants (PSI) with regard to a preoperative virtual treatment plan for genioplasty based on a new analysis method without the use of landmarks. A retrospective evaluation of a cohort of Class II and Class III patients who had undergone virtually planned orthognathic surgery (including genioplasty) was carried out. The preoperative virtual treatment plan and the postoperative outcome were fused to calculate the translational and rotational discrepancies between the 3D planning and the actual surgical outcome. The accuracy of left/right positioning was 0.25 ± 0.28 mm (p < 0.001), that of anterior/posterior positioning was 0.70 ± 0.64 mm (p < 0.001), and that of up/down-positioning was 0.45 ± 0.38 mm (p < 0.001). The rotational discrepancies were less than 2 deg. The virtually planned and postoperative positions of the chin differed significantly from each other (p < 0.001 for all rotational and translational discrepanices). The findings demonstrate that PSIs can transfer the planned virtual genioplasty into the operation theatre with small but significant deviations. However, since no conclusions can be drawn from the results regarding surgical success in terms of shaping the soft tissue profile as well as the esthetic result, no superiority of PSI over traditional plate osteosynthesis can be demonstrated. [ABSTRACT FROM AUTHOR]

The aim of this study was to verify soft tissues changes and the effect of a minimally invasive surgical technique in the nasolabial region after segmented and non-segmented Le Fort I osteotomy, using cone beam computed tomography (CBCT) evaluation of three-dimensional (3D) volume surfaces. Two groups were evaluated: group 1, bimaxillary surgery with maxillary segmentation (n = 40); group 2, bimaxillary surgery without maxillary segmentation (n = 40). In both groups, a specific alar cinching technique was used to control nasal base broadening. CBCT evaluation was performed at three different treatment time points: T0, 1 month before surgery; T1, 1 month after surgery; T2, 1 year after surgery. The results showed statistically significant differences in the nasolabial area (P < 0.001). For group 1, the mean change in alar base width (Al inf –Al inf) was 1.31 ± 1.40 mm at T1 and 0.93 ± 1.77 mm at T2; for group 2 these values were 1.12 ± 2.01 mm at T1 and 0.54 ± 1.54 mm at T2. For group 1, the mean changes in inter-alar width (Al–Al) were 1.68 ± 1.46 mm at T1 and 1.49 ± 1.33 mm at T2; for group 2, they were 2.22 ± 1.93 mm at T1 and 1.34 ± 1.79 mm at T2. The alar cinch technique proposed here appears to be effective in controlling nasolabial soft tissue widening. [ABSTRACT FROM AUTHOR]

Prosthetic rehabilitation in patients undergoing reconstructive surgery using vascularized free flaps is challenging, and functional rehabilitation of the patient with a fixed prosthesis is rare. Virtually planned maxillofacial reconstruction including simultaneous dental implantation according to the prosthodontic ideal position of the implants could further enhance dental rehabilitation. The data of 21 patients undergoing fibula free flap reconstructive surgery with CAD/CAM patient-specific reconstruction plates during the years 2015–2018 were analysed, including the applicability of the virtual plan, flap survival, duration of surgery, ischemia time, simultaneous dental implantation, implant exposure, and postoperative complications. The virtual plan could be translated to surgery in all cases. In total, 76 dental implants were simultaneously placed during primary reconstruction in the 21 patients. For 38.1% of these patients, the implants could be uncovered in secondary surgery; the mean duration until exposure was 7.6 months. The implant survival rate was 97.4% (74/76). Wound infection requiring a secondary intervention occurred in 23.8% of patients during follow-up. Virtually planned reconstruction with a fibula free flap, simultaneous dental implantation, and CAD/CAM plates allows early and functional dental rehabilitation. A dental workflow should be integrated into the virtual planning, and prosthetically favourable implant positions should determine the position of the fibula segments. [ABSTRACT FROM AUTHOR]

In craniomaxillofacial surgery we often deal with hypoplastic mandibles and mandibular asymmetries, the correction of which is critical to obtaining acceptable aesthetic results. In all of them we find common skeletal problems once growth has finished, such as an inclined occlusal plane and facial asymmetry with a stable dental occlusion. Simultaneous maxillomandibular distraction, which involves a Le Fort I osteotomy and a mandibular osteotomy with intermaxillary fixation during the period of active distraction, is an excellent technique to solve these problems. Virtual surgical planning, stereolithographic models, and surgical guides are supportive tools for obtaining excellent results. In this paper we present our experience with five cases of hypoplastic mandibles and mandibular asymmetries of different aetiologies. In all patients we achieved a considerable improvement in their physical appearance in the distance between the lateral canthus and oral commissure, the height of the mandibular ramus, the inclination of the occlusal plane, and the medial position of the chin. The benefits of virtual surgical planning in terms of choosing the optimal vector and the amount of distraction make it a promising technological tool to achieve excellent outcomes. [ABSTRACT FROM AUTHOR]

One of the recent trends in dentistry – and this in every field from the restorative to the orthodontic one– is the introduction of simplified completely digital workflows. Digital dentistry is supposed to allow dentists to work more efficiently, and this at higher precision, and with the possibility of all-in-one sessions using in-house computerized techniques. In this workflow, one of the major tools for simulating and transferring dental treatments is imaging. Both 3D low dose radiographic as well as optical imaging are playing crucial roles and have been overwhelming the market. Novel design platforms, compact and extremely fast milling and printing units are now also plentiful and rapidly being adopted in practice. Nevertheless, many of the steps in this digital dentistry process, no matter how simplified, present risks that can contribute to reduced precision and clinical difficulties. It is therefore the purpose of the article to briefly describe the role of imaging in this digital workflow, and where the pitfalls can be found that may lead to errors and imprecision. [ABSTRACT FROM AUTHOR]

The introduction of image-guided methods to bypass surgery has resulted in optimized preoperative identification of the recipients and excellent patency rates. However, the recently presented methods have also been resource-consuming. In the present study, we have reported a cost-efficient planning workflow for extracranial–intracranial (EC–IC) revascularization combined with transdural indocyanine green videoangiography (tICG-VA). We performed a retrospective review at a single tertiary referral center from 2011 to 2018. A novel software-derived workflow was applied for 25 of 92 bypass procedures during the study period. The precision and accuracy were assessed using tICG-VA identification of the cortical recipients and a comparison of the virtual and actual data. The data from a control group of 25 traditionally planned procedures were also matched. The intraoperative transfer time of the calculated coordinates averaged 0.8 minute (range, 0.4–1.9 minutes). The definitive recipients matched the targeted branches in 80%, and a neighboring branch was used in 16%. Our workflow led to a significant craniotomy size reduction in the study group compared with that in the control group (P = 0.005). tICG-VA was successfully applied in 19 cases. An average of 2 potential recipient arteries were identified transdurally, resulting in tailored durotomy and 3 craniotomy adjustments. Follow-up patency results were available for 49 bypass surgeries, comprising 54 grafts. The overall patency rate was 91% at a median follow-up period of 26 months. No significant difference was found in the patency rate between the study and control groups (P = 0.317). Our clinical results have validated the presented planning and surgical workflow and support the routine implementation of tICG-VA for recipient identification before durotomy. [ABSTRACT FROM AUTHOR]

A systematic review was conducted to investigate the three-dimensional (3D) effect of Le Fort I osteotomy on the nasolabial soft tissues. The literature search was conducted using the MEDLINE (accessed via PubMed), Embase, and Cochrane electronic databases until January 2018. A total of 333 studies were identified (PubMed, n = 292; Embase, n = 41; Cochrane Library, n = 0). Seventeen met the inclusion criteria. The studies were essentially retrospective. The risk of bias was considered high in 15 studies, medium in one study, and low in one study. 3D soft tissue analysis was performed at least 6 months after surgery (mean 8.3 months). The main image acquisition technique reported was cone beam computed tomography (CBCT), associated or not with 3D photography. Approximately 50% of the studies performed two-jaw surgery, 25% performed maxillary surgery only, and the other 25% included heterogeneous intervention groups. The most reported nasolabial changes were anterior and lateral movements of the nasomaxillary soft tissues and upper lip, together with anterior and superior movement of the nasal tip. The alar cinch suture and V–Y closure technique seemed to have little effect in counteracting the undesirable postoperative nasolabial changes. CBCT superimposition presented a reliable 3D assessment for simultaneous measurement of skeletal and soft tissue changes. [ABSTRACT FROM AUTHOR]

Mirroring and manual adaptation as the main virtual reconstruction method of midfacial defects is time demanding and ignores asymmetrical skull shapes. By using a statistical shape model (SSM), the reconstruction can be automatized and specified. The current study aims to show the ability of the SSM in the virtual reconstruction of artificial bilateral defects. Based on 131 pathologically unaffected CT scans of the adult midface region, an SSM was created. DICOM data were generated, segmented and registered on one mesh, which serves as template for the SSM. The SSM consists of the registered surface meshes and includes the shape variability of the cranial vault. Fractured or missing parts were calculated by the known shape variability of healthy midface data. Using 25 CT scans not included in the SSM, the precision of the reconstruction of virtually placed bilateral defects of the orbital floor (Group 1) and bilateral naso-orbital-ethmoid (NOE) fractures (Group 2). Distances to the corresponding parts of the intact skull were calculated to show the accuracy of the virtual reconstruction method. All defects could be reconstructed by using the SSM and GM technique. The analysis shows a high accuracy of the SSM-driven reconstruction, with a mean error of 0.75 ± 0.18 mm in group 1 and with a mean error of 0.81 ± 0.23 mm in group 2. The precision of the SSM-driven reconstruction is high and its application is easy for the clinician because of the automatization of the virtual reconstruction process in the field of computer-assisted surgery (CAS). Respecting of the natural asymmetry of the skull and the methods of GM are reasons for the high precision and the automatization of the new shown reconstruction workflow. [ABSTRACT FROM AUTHOR]

Because of the many limitations of conventional surgery planning for the treatment of orthognathic deformities, as well as advancements in computer-assisted planning, there is an urgent need for technical devices that transfer the surgical plan into the operating theatre. In this regard, additive-manufactured, patient-specific implants (PSI) and additive-manufactured interocclusal splints represent promising approaches. The aim of this retrospective study was to compare the accuracy of these two devices, with regard to preoperative virtual treatment planning for maxillary Le-Fort I advancement surgery using IPS CaseDesigner®, and based on a new analysis method without the use of landmarks. A retrospective evaluation of 18 class III patients (n(PSI) = 9; n(splint) = 9), who had undergone virtually planned orthognathic surgery (including maxillary Le Fort I advancement), was performed. The preoperative treatment plan and the postoperative outcome were combined to calculate the translational and rotational discrepancies between the 3D planning and the actual surgical outcome. For the PSI and splint groups the accuracy of left/right positioning was 0.51 mm ± 0.48 and 1.11 mm ± 1.32 respectively. The accuracy of anterior/posterior positioning was 0.39 mm ± 0.26 and 1.42 mm ± 0.87, and that of up/down-positioning was 0.44 mm ± 0.31 and 0.62 mm ± 0.47. The rotational discrepancies were less than 2° in both groups. Conclusion: The findings demonstrate that both PSI and splint approaches can accurately transfer the virtual planning into the operating theatre. However, PSIs show an overall higher accuracy, especially for anterior/posterior translational movement (p < 0.002). [ABSTRACT FROM AUTHOR]

Abstract Introduction We present our pre-operative virtual planning of complex mandibular reconstruction with a microvascular fibular composite free flap and its harvesting using our novel cutaneous positioning guide based on the perforator vessels for our soft tissue reconstructive surgery. Technical report We applied our protocol to 42 consecutive patients needing mandibular composite reconstruction. All patients were preoperatively studied with a CTA scan to evaluate the fibular pattern of vascularization and the perforator vessels three-dimensional path and position. Computer assisted surgery (CAS) was performed: a skin paddle outlining guide (SPOG) was designed to reproduce the shape and area of the planned soft tissue resection. CTA measurements and in vivo findings were compared. After performing the CTA, we classified the viable perforators in High Perforators, Medium Perforators and Low Perforators. The average diameter of the perforator vessels was 3 mm. The average difference between the measurements performed on the CTA and the intra-operative measures was 1, 4 mm. The SPOG was based on calf proximal and distal diameters. The anatomical fitting of the guide was obtained thanks to two customized flanges that embrace circumferentially the proximal and distal portions of the leg. The SPOG encompassed appropriate skin/leg regions, allowing the surgeon to localise the required perforator vessel. Conclusions CTA protocol appears to be a valuable approach to asses and virtually simulate composite mandibular reconstructions. The SPOG seems to be a valuable tool to reproduce intra-operatively the planned soft tissue area to be reconstructed. [ABSTRACT FROM AUTHOR]

Abstract Preoperative virtual planning and the use of patient-specific implants enable exact reconstruction of orbital fractures. We present our results and experience of reconstruction of isolated orbital fractures with patient-specific implants, according to the Helsinki protocol, in 15 patients who were followed up for at least three months postoperatively. The mean (range) difference between the positions of virtually planned, and postoperative, implants was 1.9 (0.5–5.6) mm. The postoperative volume of the fractured orbit was 1.34 ml less than that of the non-fractured side, but this was not clinically relevant. None of the patients required reoperation and none had any implant-related complications during follow up. We conclude that patient-specific implants are an adaptable and reliable treatment for primary orbital trauma, and that the Helsinki protocol may have wider applications in the treatment of facial fractures. [ABSTRACT FROM AUTHOR]

Abstract Surgical treatment of femoroacetabular impingement (FAI) focuses on improving the clearance for hip motion and alleviation of femoral abutment against the acetabular rim. Cam type of impingement is managed by performing an osteochondroplasty to remove the excess impinging bone from the head neck junction, thus improving the head neck offset. This procedure can be done by safe surgical dislocation, arthroscopy assisted mini-open method or all arthroscopy technique. Whatever be the approach, adequate excision of the Cam deformity is necessary to avoid suboptimal results. Under-excision leads to persistent symptoms and progression of disease, while over-excision can lead to weak bone vulnerable to fracture or disturb the labral seal. Various techniques utilized for intra-operative evaluation of amount of excision required described in literature are fluoroscopy, spherometer gauges, intra-operative Computed Tomography (CT) scan, navigation etc. Rapid prototyping, also called as three dimensional (3D) printing, is a technology to create dimensionally accurate model from a computer-assisted design. Accurate physical models can be designed from the medical imaging data like CT scans and 3D printed to aid in various medical applications. Its application in orthopaedic field is on a rise, recently. However, there is no report on utilization of this technique in surgeries for FAI. We have reported a case of Cam type FAI in an eighteen year old boy, which we treated surgically by performing osteochondroplasty using safe surgical dislocation. We did CT based virtual surgical planning to design femoral head and neck jigs, which were 3D printed and used intra-operatively to guide for adequate and optimum excision of bone at head neck junction. We found these customized jigs accurate and useful for the surgery. However, a comparison study with various other techniques is warranted for a detailed research on its usefulness and challenges. The main purpose of this article is to elaborate on the technical steps for designing of jigs for 3D printing to guide in osteochondroplasty surgery for FAI. [ABSTRACT FROM AUTHOR]

Hypoplastic left heart syndrome is a complex congenital heart disease characterised by the underdevelopment of the left ventricle normally treated with a three-stage surgical repair. In this study, a multiscale closed-loop cardio-circulatory model is created to reproduce the pre-operative condition of a patient suffering from such pathology and virtual surgery is performed. Firstly, cardio-circulatory parameters are estimated using a fully closed-loop cardio-circulatory lumped parameter model. Secondly, a 3D standalone FEA model is build up to obtain active and passive ventricular characteristics and unloaded reference state. Lastly, the 3D model of the single ventricle is coupled to the lumped parameter model of the circulation obtaining a multiscale closed-loop pre-operative model. Lacking any information on the fibre orientation, two cases were simulated: (i) fibre distributed as in the physiological right ventricle and (ii) fibre as in the physiological left ventricle. Once the pre-operative condition is satisfactorily simulated for the two cases, virtual surgery is performed. The post-operative results in the two cases highlighted similar hemodynamic behaviour but different local mechanics. This finding suggests that the knowledge of the patient-specific fibre arrangement is important to correctly estimate the single ventricle's working condition and consequently can be valuable to support clinical decision. [ABSTRACT FROM AUTHOR]

This study evaluated the accuracy of mandibular reconstruction and assessed clinical outcomes in both virtual planning and conventional surgery patients. ProPlan CMF surgical planning software was used preoperatively in the virtual planning group. In the virtual planning group, fibula flaps were harvested and osteotomized, and the mandibles were resected and reconstructed assisted by the prefabricated cutting guides and templates. The main outcome measures included the operative time, postoperative computed tomography (CT) scans, facial appearance, and occlusal function. The ischemia time and total operation time were shorter in the virtual planning group than in the conventional surgery group. High precision with the use of the cutting guides and templates was found for both the fibula and mandible, and a good fit was noted among the pre-bent plate, mandible, and fibula segments in the virtual planning group. Postoperative CT scans also showed excellent mandibular contours of the fibula flaps in accordance with virtual plans in the virtual planning group. This study demonstrated that virtual surgical planning was able to achieve more accurate mandibular reconstruction than conventional surgery. The use of prefabricated cutting guides and plates makes fibula flap moulding and placement easier, minimizes the operating time, and improves clinical outcomes. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) computer-assisted planning requires detailed visualisation of the craniomaxillofacial region and interocclusal relationship. The aim of this study was to establish and evaluate a method to create a 3D model of the craniomaxillofacial region and to adopt intraoral digital scanning to place the lower jaw into a centric relation (CR) without the need of additional plaster casts and model surgery. A standard plastic skull modified by metallic dental wires and brackets was subjected to computed tomography (CT), cone beam computed tomography (CBCT), and intraoral digital scanning. We evaluated two different virtual bite registrations, a digital scan of the buccal dental surfaces and scanning of the wax bites to position the lower jaw into a CR, and assessed the accuracy of the integration of intraoral scanning to the CT/CBCT scans. The mean registration error of corresponding mesh points for the CT and intraoral scanned images was 0.15 ± 0.12 mm, while this error was 0.18 ± 0.13 mm for the CBCT and intraoral scanned images. The mean accuracy of the two virtual bite registrations ranged from 0.41 to 0.49 mm (buccal scan technique) and from 0.65 to 1.3 mm (virtualised wax bite technique). A method for virtual bite registration was developed. It has the potential to eliminate plaster casts and model surgery and may facilitate 3D computer-assisted planning of orthognathic surgery cases. [ABSTRACT FROM AUTHOR]

Introduction Segmental maxillary osteotomy enables correction of anterior open bites. However, the outcome can be somewhat unstable, particularly if pseudarthrosis occurs. Bone grafts can be used to prevent this complication. Among the many biomaterials available for grafting, Bio-oss ® has been used successfully in a range of modalities, with studies to support several indications. This report describes a case of segmental maxillary osteotomy in which Bio-oss ® granules were used as bone grafts in the surgical gap. Presentation of case A 24-year-old female presented with anterior open bite, Angle class III posterior occlusion, and Angle class II anterior occlusion. Virtual surgical planning of the procedure predicted a gap of approximately 5 mm in the region of the osteotomy, which was bridged with Bio-oss ® granules. Discussion Although autogenous bone grafting is the gold standard due to its osteoconductive, osteoinductive, and osteogenic properties, it involves increased morbidity for the patient, unpredictable resorption rates, increased operative time, and risk of infection at the donor site. Use of the Bio-oss ® material can provide good bone stability, osteoconduction, and biocompatibility, while reducing operative time and surgical morbidity. Conclusion This is the first report of bone grafting with a granular biomaterial in segmental maxillary osteotomy. Successful formation of new bone with density greater than that of the surrounding tissue was achieved, preventing pseudarthrosis and postoperative instability. [ABSTRACT FROM AUTHOR]

The reconstruction of malunited distal radius fractures is often challenging. Virtual planning techniques and guides for drilling and resection have been used for several years to achieve anatomic reconstruction. These guides have the advantage of leading to better operative results and faster surgery. Here, we describe a technique using a simple implant independent 3-dimensional printed drill guide and template to simplify the surgical reconstruction of a malunited distal radius fracture. [ABSTRACT FROM AUTHOR]

The bone-machine interface is a vital first step for biomechanical testing. It remains challenging to restore the original alignment of the specimen with respect to the test setup. To overcome this issue, we developed a methodology based on virtual planning and 3D printing. In this paper, the methodology is outlined and a proof of concept is presented based on a series of cadaveric tests performed on our knee simulator. The tests described in this paper reached an accuracy within 3–4° and 3–4 mm with respect to the virtual planning. It is however the authors׳ belief that the method has the potential to achieve an accuracy within one degree and one millimeter. Therefore, this approach can aid in reducing the imprecisions in biomechanical tests (e.g. knee simulator tests for evaluating knee kinematics) and improve the consistency of the bone-machine interface. [ABSTRACT FROM AUTHOR]

We compared two methods of planning virtual alveolar moulding as the first step in nasoalveolar moulding to provide the basis for an automated process to fabricate nasoalveolar moulding appliances by using computer-assisted design and computer-aided manufacturing (CAD/CAM). First, the initial intraoral casts taken from seven newborn babies with complete unilateral cleft lip and palate were digitised. This was repeated for the target models after conventional nasoalveolar moulding had been completed. The initial digital model for each patient was then virtually modified by two different modelling techniques to achieve the corresponding target model: parametric and freeform modelling with the software Geomagic ® . The digitally-remodelled casts were quantitatively compared with the actual target model for each patient, and the comparison between the two modified models and the target model showed that freeform modelling of the initial cast was successful (mean (SD) deviation n = 7, +0.723 (0.148) to −0.694 (0.157) mm) but needed continuous orientation and was difficult to automate. The results from the parametric modelling (mean (SD) deviation, n = 7, +1.168 (0.185) to −1.067 (0.221) mm) were not as good as those from freeform modelling. During parametric modelling, we found some irregularities on the surface, and transverse growth of the maxilla was not accounted for. However, this method seems to be the right one as far as automation is concerned. In addition, an external algorithm must be implemented because the function of the commercial software is limited. [ABSTRACT FROM AUTHOR]

Summary Introduction In a deep inferior epigastric perforator (DIEP) flap breast reconstruction, computed tomography angiography (CTA) is currently considered as the gold standard in preoperative imaging for this procedure. Unidirectional Doppler ultrasound (US) is frequently used; however, this method does not distinguish the main axial vessels from perforator arteries at the height of the fascia, it has a limited penetration depth, and it cannot assess the branching patterns of the deep inferior arteries. A new method and system were developed, which consisted of a video projector preoperatively displaying the location and intramuscular course of the artery perforators and subcutaneous branching on the patient's abdomen. Method All patients ( n = 9) underwent a standard protocol: a preoperative CTA was performed and the DIEPs were localized using a unidirectional Doppler probe. In addition, a three-dimensional (3D) reconstruction of the perforator locations based on CTA was projected on the abdomen of the patients. All projected perforator locations were assessed using a unidirectional Doppler probe. The intraoperative results were collected for comparison. Results A total of 88 locations were marked with the use of unidirectional Doppler and a total of 100 perforators were projected ( p = 0.38). In 98 out of 100 projected perforator locations, a Doppler signal was audible. The intraoperative results demonstrate that 19 out of 34 transplanted perforators were correctly identified with unidirectional Doppler (56.9% ± 31.4%), where the projection method properly revealed 29 locations (84.3% ± 25.8%) ( p = 0.030). Conclusion The projection method is not only capable of providing more information and identifying more perforators used for transplantation than unidirectional Doppler probing but also more accurate in pointing out the corresponding perforator found intraoperatively. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the additional costs incurred by using a computer-aided design/computer-aided manufacturing (CAD/CAM) technique for reconstructing maxillofacial defects by analyzing typical cases. The medical charts of 11 consecutive patients who were subjected to the CAD/CAM technique were considered, and invoices from the companies providing the CAD/CAM devices were reviewed for every case. The number of devices used was significantly correlated with cost ( r = 0.880; p < 0.001). Significant differences in mean costs were found between cases in which prebent reconstruction plates were used (€3346.00 ± €29.00) and cases in which they were not (€2534.22 ± €264.48; p < 0.001). Significant differences were also obtained between the costs of two, three and four devices, even when ignoring the cost of reconstruction plates. Additional fees provided by statutory health insurance covered a mean of 171.5% ± 25.6% of the cost of the CAD/CAM devices. Since the additional fees provide financial compensation, we believe that the CAD/CAM technique is suited for wide application and not restricted to complex cases. Where additional fees/funds are not available, the CAD/CAM technique might be unprofitable, so the decision whether or not to use it remains a case-to-case decision with respect to cost versus benefit. [ABSTRACT FROM AUTHOR]

Accurate transfer of a preoperatively planned osteotomy plane to the bone is of significance for corrective surgery, tumor resection, implant positioning and evaluation of new osteotomy techniques. Methods for comparing a preoperatively planned osteotomy plane with a surgical cut exist but the accuracy of these techniques are either limited or unknown. This paper proposes and evaluates a CT-based technique that enables comparing virtual with actual osteotomy planes. The methodological accuracy and reproducibility of the technique is evaluated using CT-derived volume data of a cadaver limb, which serves to plan TKA osteotomies in 3-D space and to simulate perfect osteotomies not hampered by surgical errors. The methodological variability of the technique is further investigated with repeated CT scans after actual osteotomy surgery of the same cadaver specimen. Plane displacement ( d err ) and angulation errors in the sagittal and coronal plane ( β err , γ err ) are measured with high accuracy and reproducibility ( d err = −0.11 ± 0.06 mm; β err = 0.08 ± 0.04°, γ err = −0.03 ± 0.03°). The proposed method for evaluating an osteotomy plane position and orientation has a high intrinsic accuracy and reproducibility. The method can be of great value for measuring the transfer accuracy of new techniques for positioning and orienting a surgical cut in 3-D space. [ABSTRACT FROM AUTHOR]

Abstract: Inaccurate visualization of the inter-occlusal relationship has raised an important challenge to virtual planning for orthognathic surgery based on cone beam computerized tomography (CBCT). The aim of this study was to evaluate an innovative workflow for orthognathic surgery planning and surgical splint fabrication. The clinical protocol consists of a single cone beam computerized tomography (CBCT) scan of the patient, surface scanning of the dental arches with an intraoral digital scanner, and subsequent fusion of the two datasets. The “virtual patient” thus created undergoes virtual surgery, and the resulting file with the intermediate intermaxillary relationship is used to obtain the intermediate splint by CAD/CAM technology (computer-aided design and computer-aided manufacturing). A proof-of-concept study was performed in order to assess the accuracy and reliability of this protocol. The study comprised two parts: an in vitro evaluation on three dentate skull models and a prospective in vivo assessment on six consecutive patients. Vector error calculation between the virtually simulated intermaxillary position and the intraoperative intermediate intermaxillary relationship revealed high accuracy. The greatest average variation corresponded to the y axis. Compared to previously described methods for obtaining an augmented three-dimensional virtual model, this procedure eliminates the need for dental impressions, simplifies the necessary technical steps and computational work, and reduces the patient's exposure to ionizing radiation. [Copyright &y& Elsevier]

Introduction: Post- resection defects in the area of the head and neck frequently result in functional impairment of the masticatory system and unaesthetic outcome in the facial appearance. In pediatric population they exert a devastating effect on speech development, breathing and facial growth leading to secondary deformations which are extremely challenging in reconstruction by means of conventional surgery protocols.Material and Methods: 21 patients (14 males/ 7 females) aged 4-17 years old, treated between 2015 and 2019 due to malignant/benign tumors or congenital deformities requiring mandible resection were enrolled in the study. All patients underwent Virtual Surgical Planning (VSP), mandible tumor resection with use surgery guides and defect reconstruction with microvascular bone graft supported with custom implants. Postoperatively, 3D models used for the planning and postoperative 3D model of the reconstructed mandible were compared using authors method based on easily measurable morphometric measurements (3 angles, 3 linear dimensions), allowing a three-dimensional quantitative assessment of postoperative outcomes of the surgery. Linear regression analysis and one-way analysis of variance were used to evaluate the clinical material. The difference was considered significant if p < 0.05.Results: Free fibula flap (FFF) was most commonly used type of the reconstruction of the pediatric mandible. The average maximum deviation for the analyzed cases was 7.7 mm, and the average minimum deviation was -6.09 mm, however without significant differences and the postoperative position of the mandible condyle was comparable to the position designed in the 3DVSP preoperatively. Position of the whole reconstructed mandible by means of individually planned grafts and plates provided comparable position of the ramus and mandible body and no chin deviation as the differences between the pre-operative axial and sagittal angles and their post-operative equivalents were insignificant (p > 0,05).Conclusions: This study confirms applicability of the 3DVSP in pediatric craniomaxillofacial surgery. Preoperative planning of the osteotomies, grafting technique and production of the individualized guides and implants provides precise tumor resection and immediate reconstruction adjusted to the specific anatomy of the pediatric patients. [ABSTRACT FROM AUTHOR]

Abstract: The free fibular flap is the standard procedure for reconstructing mandibular defects. The graft has to be contoured to fit the defect so preoperative planning is required. The systems used previously do not allow transfer of the surgical plan to the operation room in an optimal way. The authors present a method to bring the virtual plan to real time surgery using a rapid prototyping guide. Planning was conducted using the Surgicase CMF software simulating surgery on a workstation. The osteotomies were translated into a rapid prototyping guide, sterilised and applied during surgery on the fibula allowing for the osteotomies and osteosynthesis to be performed with intact circulation. During reconstruction the authors were able to choose the best site for the osteotomies regarding circulation and as a result increased the precision and speed of treatment. [Copyright &y& Elsevier]

Abstract: Computer-assisted maxillofacial orthognathic surgery is an emerging and interdisciplinary field linking orthognathic surgery, remote signal engineering and three-dimensional (3D) medical imaging. Most of the computational solutions already developed make use of different specialized systems which introduce difficulties both in the information transfer from one stage to the others and in the use of such systems by surgeons. Trying to address such issue, in this work we present a common computer-based system that integrates proposed modules for planning and assisting the maxillofacial surgery. With that we propose to replace the current standard orthognathic preoperative planning, and to bring information from a virtual planning to the real operative field. The system prototype, including three-dimensional cephalometric analysis, static and dynamic virtual orthognathic planning, and mixed reality transfer of information to the operation room, is described and the first results obtained are presented. [Copyright &y& Elsevier]

Summary: Aim: To simulate the surgery of dysgnathia, several forms of computer software allowing two-dimensional ‘virtual’ planning are frequently used. However, in many cases it is not possible to transfer the virtual plan accurately to the surgical site. It is the purpose of this study to find the errors likely to occur when transferring the data. Methods: In 22 bimaxillary osteotomies for dysgnathia, the results of preoperative planning were compared with the surgical outcomes. The programme WinCeph 4.19 (Compudent) was used for cephalometric analyses and simulation of the operations. Results: Six major skeletal parameters were evaluated when comparing both the planned and the actual outcome, and the following results were recorded: Delta-SNA 1.53° (±1.20), Delta-SNB 1.67° (±1.29), Delta-ANB 1.62° (±1.47), Delta-NL-NSL 3.9° (±2.30), Delta-ML-NSL 3.6°(±3.7) and Delta-ArGoMe 6.1°(±4.6). Conclusion: It was anticipated that the most important differences between planned and surgical outcomes were found to be in the vertical changes. Planning and data transfer was comparatively accurate with regard to sagittal data. Apart from several mechanical methods for data transfer, systems using navigation are therefore being discussed and used increasingly. They ensure accurate data transfer to the surgical site. [Copyright &y& Elsevier]

Rehabilitation post reconstruction in head and neck cancer surgery is a vital component to improving quality of life. In this paper we discuss the current approaches to reconstruction of the maxilla and mandible and how they pertain to rehabilitation. There is a detailed discussion of dental rehabilitative challenges with different composite flaps and ways to solve those challenges. We conclude with a discussion about future approaches to reconstruction and how they will impact on improving rehabilitative outcomes and ultimately improve the quality of life of our patients. [ABSTRACT FROM AUTHOR]