Computer-assisted Reconstruction Research Articles

Exploring the use of Virtual Surgical Planning (VSP) in Maxillofacial Reconstructions

ABSTRACT Background: Virtual surgical planning (VSG), also known as computer-assisted reconstruction, has started to become the norm for more complex patients in many centers in recent times. Aim: This study was conducted to evaluate the VSG in maxillofacial reconstruction surgery. Methods and Materials: This study included 20 patients who underwent surgery for maxillofacial reconstruction. The study participants were divided into two main categories: Category 1: Conventional surgical planning (CSG). Category 2: VSG. The surgical planning in both categories, including the evaluation of volume of defect, length, width, and height of graft, to be placed. Results: The gap between defect to be reconstructed and graft placed was greater in CSG as compared to VSG. The distance of graft from actual location was lesser in VSG as compared to CSG. The findings were significant statistically. Frequency of success was 93.21% and 97.47%, respectively. The frequency of success was greater in VSG as compared to CSG. Conclusion: Virtual surgical planning is more effective in maxillofacial reconstruction surgery.

Computer-Assisted Reconstruction of an Orbital Trauma Case Treated with a Patient-Specific Titanium Prosthesis

Virtual planning is ideally suited for maxillofacial operations as it allows the surgeon to assess the bony and critical neurovascular structures and enables him to plan osteotomies and fracture reductions. This study aims to propose the use of titanium-based patient-specific implants (PSI), along with virtual surgical planning to assess the advantages and the complications in a case of orbital reconstruction. A three-dimensional model of the skull was generated using computed tomography (CT) data of a female patient using Mimics software (version 19, Materialize, Leuven, Belgium). Numerical PSI models were designed using 3-Matic software (version 13, Materialize, Leuven, Belgium) and the non-affected orbit as a template. Surgical virtual planning showed the suitability of the use of the numerical models in traumatic surgical rehabilitation. Moreover, the digital printing process enabled the trial of the designed PSIs on the patient’s face before the surgery. Reconstruction Biomechanical studies are an essential part of understanding the limits of maxillofacial traumas. The surgical results confirmed the virtual predictions, and the orbital reconstruction seems to be more enhanced and facilitated.

A Century of French Railways: The Value of Remote Sensing and VGI in the Fusion of Historical Data

Providing long-term data about the evolution of railway networks in Europe may help us understand how European Union (EU) member states behave in the long-term, and how they can comply with present EU recommendations. This paper proposes a methodology for collecting data about railway stations, at the maximal extent of the French railway network, a century ago.The expected outcome is a geocoded dataset of French railway stations (gares), which: (a) links gares to each other, (b) links gares with French communes, the basic administrative level for statistical information. Present stations are well documented in public data, but thousands of past stations are sparsely recorded, not geocoded, and often ignored, except in volunteer geographic information (VGI), either collaboratively through Wikipedia or individually. VGI is very valuable in keeping track of that heritage, and remote sensing, including aerial photography is often the last chance to obtain precise locations. The approach is a series of steps: (1) meta-analysis of the public datasets, (2) three-steps fusion: measure-decision-combination, between public datasets, (3) computer-assisted geocoding for ‘gares’ where fusion fails, (4) integration of additional gares gathered from VGI, (5) automated quality control, indicating where quality is questionable. These five families of methods, form a comprehensive computer-assisted reconstruction process (CARP), which constitutes the core of this paper. The outcome is a reliable dataset—in geojson format under open license—encompassing (by January 2021) more than 10,700 items linked to about 7500 of the 35,500 communes of France: that is 60% more than recorded before. This work demonstrates: (a) it is possible to reconstruct transport data from the past, at a national scale; (b) the value of remote sensing and of VGI is considerable in completing public sources from an historical perspective; (c) data quality can be monitored all along the process and (d) the geocoded outcome is ready for a large variety of further studies with statistical data (demography, density, space coverage, CO2 simulation, environmental policies, etc.).

Post-traumatic maxillofacial reconstruction with vascularized flaps and digital techniques: 10-year experience

The aim of this study was to present a treatment protocol for the individual repair of post-traumatic maxillofacial bone defects with vascularized flaps assisted by digital techniques. This study reviewed 20 patients with post-traumatic maxillofacial bone defects who underwent reconstruction with composite vascularized bone flaps assisted by digital techniques between April 2009 and July 2019. Preoperative computed tomography (CT) data were imported into ProPlan CMF software to complete virtual fracture reduction and reconstruction. Surgical navigation, three-dimensionally (3D) printed surgical plates, and prefabricated titanium mesh/plates were used to guide the actual surgery. All patients underwent open reduction and internal fixation and reconstruction surgery in one stage. CT data obtained at 1 week postoperative were imported into Geomagic Control software to evaluate the accuracy of the virtual surgical plan. The mean follow-up interval was 24 months (range 6–96 months). Donor and recipient site morbidity and second-stage procedures to rehabilitate the dentition and cosmetic organs were recorded. The flap success rate was 100%. Nine patients had deep circumflex iliac artery flaps and eleven patients had fibula flaps. The accuracy of computer-assisted surgery was 4.4±0.8mm. There were no postoperative complications. This study is novel in presenting a treatment protocol for individual computer-assisted reconstruction for post-traumatic maxillofacial bone defects with vascularized flaps.

A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible

Valid comparisons of postoperative accuracy results in computer-assisted reconstruction of the mandible are difficult due to heterogeneity in imaging modalities, mandibular defect classification, and evaluation methodologies between studies. This guideline uses a step-by-step approach guiding the process of imaging, classification of mandibular defects and volume assessment of three-dimensional (3D) models, after which a legitimized quantitative accuracy evaluation method can be performed between the postoperative clinical situation and the preoperative virtual plan. The condyles and the vertical and horizontal corners of the mandible are used as bony landmarks to define virtual lines in the computer-assisted surgery (CAS) software. Between these lines the axial, coronal, and both sagittal mandibular angles are calculated on both pre- and postoperative 3D models of the (neo)mandible and subsequently the deviations are calculated. By superimposing the postoperative 3D model to the preoperative virtually planned 3D model, which is fixed to the XYZ axis, the deviation between pre- and postoperative virtually planned dental implant positions can be calculated. This protocol continues and specifies an earlier publication of this evaluation guideline.

A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible

A Postoperative Evaluation Guideline for Computer-Assisted Reconstruction of the Mandible

5202Zero- or near-zero fluoroscopy radiofrequency catheter ablation for aortic sinus cusp idiopathic ventricular arrhythmias

Abstract Background Complete elimination of fluoroscopy during radiofrequency catheter ablation (RFCA) of idiopathic ventricular arrhythmias (IVA) originating from aortic sinus cusp (ASC) may be challenging, requires confirmation of coronary arteries ostia and could be associated with potential risk of collateral damage and severe complications. Purpose To validate the implementation, feasibility, learning curve, safety and efficacy of zero-fluoroscopy (ZF) approach in centers using near-zero fluoroscopy (NOX) approach for RFCA of idiopathic premature ventricular complexes/ventricular tachycardias (PVCs/VTs) from ASC. Methods From 2012 to 2018, we prospectively enrolled 106 consecutive patients (age: 49±19, males: 58%, children: 7%, 108 PVC/VT focuses from ASC, PVCs/24h: 23808±22006) with ASC-IVA. Patients were unselected and referred for ZF or NOX approach using three dimensional electroanatomic system- 3D EAM without intracardiac or transesophageal echocardiography. The choice of ZF and NOX was based on the first operator experience and from 2014 three experienced operators and three fellows performed ZF as an intention-to-treat approach. The peri-procedural, short-term outcome as well as learning curve of ZF in ASC were evaluated with documentation of reasons for cross-over to NOX approach. Results Out of 108 focuses there were majority of left coronary cusps and left/right junctions sites of origin [other rare locations: right coronary cusp (n=7); non-coronary cusp, n=6)]. On intention-to-treat 61/76 (80%) cases were completed without fluoroscopy in ZF-approach. Additionally, 30/30 (100%) cases were completed with NOX. The main reasons for fluoroscopy use in ZF approach (conversion to NOX) were: the need for elective valsalvography plus coronary angiography (n=6), urgent coronary angiography due to validation of transient uncomplicated coronary spasms and ST elevation (n=2), catheter stability checking (n=2), femoral access site confirmation (n=1) and navigation problem (n=1). No significant differences were found in the acute and short-term success rates between ZF and NOX (90% vs 88%, P=NS) and no major complications occurred. The procedure time, fluoroscopy time and ablation time were 66.8±26.9; 3.6±7.2 and 7.3±5.5 min, respectively. The gathering experience of ZF approach, computer-assisted ECG analysis and 3D-EAM reconstruction of aortic root and coronary artery ostia resulted in significant reduction of NOX approach between early and late period [median (n=53): 2012–2016 vs 2017–2018, 40/53 (76%) vs 5/53 (8%), p<0.001]. Conclusion ZF can be completed in majority of patients with ASC-IVA especially after appropriate training and operators' experience with NOX. ZF approach guided by 3D-EAM is feasible, safe, and effective for treatment of ASC-IVA with importance of training and preprocedural imaging for exclusion of coronary anomalies or validation of coronary arteries ostia by 3D-EAM.

Ten-Year Results of Reconstruction for Rheumatoid Cervical Spine Lesions and Occurrence Factor of Subaxial Subluxation.

Study DesignRetrospective chart review.PurposeThis study evaluated long-term surgical outcomes of computer-assisted reconstruction using transarticular or cervical pedicle screws for cervical spine lesions caused by advanced rheumatoid arthritis (RA).Overview of LiteratureWe routinely employ C1–C2 transarticular and cervical pedicle screw instrumentation to reconstruct advanced and unstable RA cervical lesions. However, few reports are available on the long-term results of surgical reconstruction for rheumatoid cervical disorders, particularly regarding cervical pedicle screw fixation.MethodsSix subjects (all female) with RA cervical lesions who underwent atlantoaxial or occipitocervical fixation and were followed for at least 10 years were retrospectively studied. A frameless, stereotactic, optoelectronic, computed tomography-based image guidance system was used for correct screw placement. Variables including the Japanese Orthopaedic Association score, EuroQol, Ranawat value, and C2–C7 angle before and 2, 5, and 10 years after surgery were assessed along with the occurrence of subaxial subluxation (SAS).ResultsMean age at initial surgery was 58.2±7 years (range, 51–68 years), and mean follow-up period was 141±11 months (range, 122–153 months). Lesions included atlantoaxial subluxation (AAS, n=2) and AAS+vertical subluxation (n=4). Mean C2–C7 lordotic angle before and 2, 5, and 10 years after surgery was 20.1°±6.1°, 21.0°±4.0°, 18.8°±4.7°, and 17.8°±5.3°, respectively. SAS did not occur in cases maintaining the C2–C7 lordotic angle. In two cases where the C2–C7 lordotic angle declined from 5 years postoperatively, SAS occurred at the C2–C3 level in one and at the C4–C5 level in the other, both of which required reoperation.ConclusionsPatients with rheumatoid cervical lesions who undergo atlantoaxial or occipitocervical fixation using C1–C2 transarticular or pedicle screws carry a risk of SAS for up to 10 years postoperatively, which may require reoperation.

Advances in computer-aided design for bony free-flap reconstruction.

The current article reviews the most recent publications of computer-assisted reconstruction using bony free flaps, emphasizing on comparative reports using these novel techniques. Computer-aided reconstruction has shown some benefits in comparison with traditional techniques and some of the perceived limitations are currently being addressed in the latest reports. Still, there is a lack of appropriate comparative studies and unblinded measurements to establish solid conclusions. Despite the application of new technologies showed encouraging results, it is premature to state that the traditional technique should be replaced by the modern approaches.

Which Patients With Ossifying Fibroma of the Jaws Would Be Suitable for Radical Ablative Surgery?

The aim of authors' study was to present their 10-year experience in the treatment of giant ossifying fibroma (GOF), and to prove if GOF can be totally excised preventing recurrence. The authors' secondary goal was to study the aesthetic and functional outcomes after radical resection of GOF followed by immediate reconstruction. Eighteen patients who underwent radical ablative surgery of GOF of the jaw followed by immediate reconstruction with vascularized fibula flap or ilium flap between May 2003 and May 2013 were taken. Recurrence rate was statistically observed and 2-year postoperative aesthetic and functional outcomes were evaluated. The average length of follow-up was 4.5 years. There was no residual tumor or tumor recurrence observed in any patient during the mean follow-up of 4.5 years, and good cosmesis and functional outcome was noted after ablative surgery of GOF followed by computer-assisted reconstruction. For giant OF, if it is mainly located in the jaws without invasion of the skull base and/or pterygoid process, radical surgical treatment should be performed for prevention of tumor recurrence. And good aesthetic and functional results can be achieved by immediate computer-assisted reconstruction and dental rehabilitation.

4D Tumorigenesis Model for Quantitating Coalescence, Directed Cell Motility and Chemotaxis, Identifying Unique Cell Behaviors, and Testing Anticancer Drugs.

A 4D high-resolution computer-assisted reconstruction and motion analysis system has been developed and applied to the long-term (14-30 days) analysis of cancer cells migrating and aggregating within a 3D matrix. 4D tumorigenesis models more closely approximate the tumor microenvironment than 2D substrates and, therefore, are improved tools for elucidating the interactions within the tumor microenvironment that promote growth and metastasis. The model we describe here can be used to analyze the growth of tumor cells, aggregate coalescence, directed cell motility and chemotaxis, matrix degradation, the effects of anticancer drugs, and the behavior of immune and endothelial cells mixed with cancer cells. The information given in this chapter is also intended to acquaint the reader with computer-assisted methods and algorithms that can be used for high-resolution 3D reconstruction and quantitative motion analysis.

Computer-assisted Virtual Surgery and Splint Fabrication for Paediatric Mandible Fracture

Closed reduction using acrylic splints with circummandibular fixation has been known to be useful techniques in pediatric mandibular fractures. However, this technique has some shortcomings, including needs for impression taking or additional laboratory process, which can increase the exposure time of general anesthesia or make an additional sedation visit. Recently, the advancement of computer-aided maxillofacial surgery offers to clinicians to expansion of its application. This case report represents a technique of computer-assisted virtual reconstruction and computer-aided designed splint fabrication in a 2-year-old boy with mandibular body fracture.

Personalized Face Modeling for Photorealistic Synthesis

Faces play a key role in revealing the personalized attributes such as the identity, emotion, health condition, etc. Due to the importance of faces, computer-assisted face modeling and reconstruction have been actively studied both in computer vision and graphics community. Especially, face reconstruction and realistic face synthesis are well-grounded research problems and various approaches have been proposed during the last decade. In this paper, we discuss a wide range of existing work in face modeling by introducing their target applications, categorizing them upon their methodology and addressing their strength and weakness on performance. Finally, we introduce remaining research issues and suggest the future research direction in face modeling. We believe that this paper provides a high-level overview on face modeling techniques and helps understand the major research issues and the trends of methodology.

Filling the gap. Human cranial remains from Gombore II (Melka Kunture, Ethiopia; ca. 850 ka) and the origin of Homo heidelbergensis.

African archaic humans dated to around 1,0 Ma share morphological affinities with Homo ergaster and appear distinct in cranio-dental morphology from those of the Middle Pleistocene that are referred to Homo heidelbergensis. This observation suggests a taxonomic and phylogenetic discontinuity in Africa that ranges across the Matuyama/Brunhes reversal (780 ka). Yet, the fossil record between roughly 900 and 600 ka is notoriously poor. In this context, the Early Stone Age site of Gombore II, in the Melka Kunture formation (Upper Awash, Ethiopia), provides a privileged case-study. In the Acheulean layer of Gombore II, somewhat more recent than 875 ±10 ka, two large cranial fragments were discovered in 1973 and 1975 respectively: a partial left parietal (Melka Kunture 1) and a right portion of the frontal bone (Melka Kunture 2), which probably belonged to the same cranium. We present here the first detailed description and computer-assisted reconstruction of the morphology of the cranial vault pertaining to these fossil fragments. Our analysis suggest that the human fossil specimen from Gombore II fills a phenetic gap between Homo ergaster and Homo heidelbergensis. This appears in agreement with the chronology of such a partial cranial vault, which therefore represents at present one of the best available candidates (if any) for the origin of Homo heidelbergensis in Africa.

A computer-assisted 3D model for analyzing the aggregation of tumorigenic cells reveals specialized behaviors and unique cell types that facilitate aggregate coalescence.

We have developed a 4D computer-assisted reconstruction and motion analysis system, J3D-DIAS 4.1, and applied it to the reconstruction and motion analysis of tumorigenic cells in a 3D matrix. The system is unique in that it is fast, high-resolution, acquires optical sections using DIC microscopy (hence there is no associated photoxicity), and is capable of long-term 4D reconstruction. Specifically, a z-series at 5 μm increments can be acquired in less than a minute on tissue samples embedded in a 1.5 mm thick 3D Matrigel matrix. Reconstruction can be repeated at intervals as short as every minute and continued for 30 days or longer. Images are converted to mathematical representations from which quantitative parameters can be derived. Application of this system to cancer cells from established lines and fresh tumor tissue has revealed unique behaviors and cell types not present in non-tumorigenic lines. We report here that cells from tumorigenic lines and tumors undergo rapid coalescence in 3D, mediated by specific cell types that we have named “facilitators” and “probes.” A third cell type, the “dervish”, is capable of rapid movement through the gel and does not adhere to it. These cell types have never before been described. Our data suggest that tumorigenesis in vitro is a developmental process involving coalescence facilitated by specialized cells that culminates in large hollow spheres with complex architecture. The unique effects of select monoclonal antibodies on these processes demonstrate the usefulness of the model for analyzing the mechanisms of anti-cancer drugs.

Stability Outcomes following Computer-Assisted ACL Reconstruction.

Purpose. The purpose of this study was to determine whether intraoperative prereconstruction stability measurements and/or patient characteristics were associated with final knee stability after computer-assisted ACL reconstruction. Methods. This was a retrospective review of all patients who underwent computer-assisted single-bundle ACL reconstruction by a single surgeon. Prereconstruction intraoperative stability measurements were correlated with patient characteristics and postreconstruction stability measurements. 143 patients were included (87 male and 56 female). Average age was 29.8 years (SD ± 11.8). Results. Females were found to have significantly more pre- and postreconstruction internal rotation than males (P < 0.001 and P = 0.001, resp.). Patients with additional intra-articular injuries demonstrated more prereconstruction anterior instability than patients with isolated ACL tears (P < 0.001). After reconstruction, these patients also had higher residual anterior translation (P = 0.01). Among all patients with ACL reconstructions, the percent of correction of anterior translation was found to be significantly higher than the percent of correction for internal or external rotation (P < 0.001). Conclusion. Anterior translation was corrected the most using a single-bundle ACL reconstruction. Females had higher pre- and postoperative internal rotation. Patients with additional injuries had greater original anterior translation and less operative correction of anterior translation compared to patients with isolated ACL tears.

Computer-assisted surgery for knee ligament reconstruction.

Anterior cruciate ligament (ACL) reconstruction is one of the most frequently performed orthopaedic procedures. The most common technical cause of reconstruction failure is graft malpositioning. Computer-assisted surgery (CAS) aims to improve the accuracy of graft placement. Although posterior cruciate ligament (PCL) injury and reconstruction are far less common, PCL reconstruction has comparable difficulties relating to graft placement. This is an update of a Cochrane review first published in 2011. To assess the effects of computer-assisted reconstruction surgery versus conventional operating techniques for ACL or PCL injuries in adults. For this update, we searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (from 2010 to July 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 5, 2013), MEDLINE (from 2010 to July 2013), EMBASE (from 2010 to July 2013), CINAHL (from 2010 to July 2013), article references and prospective trial registers. We included randomized controlled trials (RCTs) and quasi-randomized controlled trials that compared CAS for ACL or PCL reconstruction versus conventional operating techniques not involving CAS. Two authors independently screened search results, assessed the risk of bias in the studies and extracted data. Where appropriate, we pooled data using risk ratios (RR) or mean differences (MD), both with 95% confidence intervals (CI). The updated search resulted in the inclusion of one new study. This review now includes five RCTs with 366 participants. There were more female than male participants (70% were female); their ages ranged from 14 to 53 years. All trials involved ACL reconstructions performed by experienced surgeons.Assessing the studies' risk of bias was hampered by poor reporting of trial methods, and consequently several studies were judged to be 'unclear' for several types of bias. One trial presenting primary outcome data was at high risk of detection bias from lack of clinician blinding and attrition bias from an unaccounted loss to follow-up at two years.We found moderate quality evidence (three trials, 193 participants) of no clinically relevant difference between CAS and conventional surgery in International Knee Documentation Committee (IKDC) subjective scores (self-reported measure of knee function; scale of 0 to 100 where 100 was best function). Pooled data from two of these trials (120 participants) showed a small, but clinically irrelevant difference favouring CAS (MD 2.05, 95% CI -2.16 to 6.25). A third trial (73 participants) also found minimal difference in IKDC subjective scores (reported MD 0.2).We found low quality evidence (two trials, 120 participants) showing no difference between the two groups in Lysholm scores, also measured on a scale 0 to 100 where 100 is best function (MD 0.25, 95% CI -3.75 to 4.25). We found very low quality evidence (one trial, 40 participants) showing no difference between the two groups in Tegner scores. We found low quality evidence (three trials, 173 participants) showing the majority of participants in both groups were assessed as having normal or nearly normal knee function (86/87 with CAS versus 84/86 with no CAS; RR 1.01, 95% CI 0.96 to 1.06).Similarly, no differences were found for our secondary outcome measures of knee stability, loss in range of motion and tunnel placement. None of the trials reported on re-operation.No adverse post-surgical events were reported in two trials (133 participants); this outcome was not reported by the other three trials.CAS use was associated with longer operating times compared with conventional operating techniques: the mean difference in operating times reported in the studies ranged between 9 and 27 minutes. From the available evidence, we are unable to demonstrate or refute a favourable effect of CAS for cruciate ligament reconstructions of the knee compared with conventional reconstructions. However, the currently available evidence does not indicate that CAS in knee ligament reconstruction improves outcome. There is a need for improved reporting of future studies of this technology.

English

previously programmed with 3D surgical planning, construction of cutting and reconstructive guides, laser prebended reconstructive plate. There were no drawbacks during the surgical steps. High precision of cutting guides and a good fit of the pre-bended plate both on the mandible and on the fibula were found intra-operatively. Extreme precision in bone-to-bone contact and position between mandible and fibula graft was also noticed. Conclusion We posit that using computerassisted mandibular reconstruction and virtual surgical planning for mandible reconstruction after ablative surgery will significantly improve the functional results, allowing for accurate recovery of function and facial contour and decreasing surgical time.

Multi-centre experience with computer-assisted fibular reconstruction of maxillary and mandibular defects: a retrospective case series

Multi-centre experience with computer-assisted fibular reconstruction of maxillary and mandibular defects: a retrospective case series

Maxillofacial firearm injuries: a protocol for management in Asyut University Hospital

none of the published studies reported objective means to evaluate accuracy of reconstruction. Methods: Twelve patients with unilateral massively displaced or comminuted orbitozygomatic complex fractures received computer-assisted reconstruction guided by stereolithographic models and zygomatic templates. Titanium meshes and fixation plates were bent onto the models preoperatively, while the templates were used intraoperatively for guidance of zygomatic reduction into the pre-planned position. Linear and angular measurements were used to assess accuracy of reconstruction on the postoperative 3D-CT images. Results: Results are currently being generated and will be presented and disussed during the conference.