Planning tools and indications for "virtual surgery" for the Bonebridge bone conduction system.

The advantages of advanced computer-assisted diagnostics and three-dimensional preoperative planning on implant position in orbital reconstruction

Assessing glenoid arthroplasty component positioning for surgeons utilizing surgical planning software

ObjectiveWe performed a retrospective study to compare the accuracy of preoperative planning using three-dimensional AI-HIP software and traditional two-dimensional manual templating to predict the size and position of prostheses. The purpose of this study was to evaluate the accuracy of AI-HIP in preoperative planning for primary total hip arthroplasty.MethodsIn total, 316 hips treated from April 2019 to June 2020 were retrospectively reviewed. A typical preoperative planning process for patients was implemented to compare the accuracy of the two preoperative planning methods with respect to prosthetic size and position. Intraclass correlation coefficients (ICCs) were used to evaluate the homogeneity between the actual prosthetic size and position and the preoperative planning method.ResultsWhen AI-HIP software and manual templating were used for preoperative planning, the stem agreement was 87.7% and 58.9%, respectively, and the cup agreement was 94.0% and 65.2%, respectively. The results showed that when AI-HIP software was used, an extremely high level of consistency (ICC > 0.95) was achieved for the femoral stem size, cup size, and femoral osteotomy level (ICC = 0.972, 0.962, and 0.961, respectively).ConclusionAI-HIP software showed excellent reliability for predicting the component size and implant position in primary total hip arthroplasty.

BackgroundDelayed reconstruction of acetabular fractures remains a challenging task for orthopedists because of malunion, fracture line absorption, and scar formation. Accurate osteotomy, interfragmentary release, and proper adaptation of plates are keys to successful surgery. Prevention of superior gluteal artery (SGA) injury induced by cleaning of the osteotylus and reduction of the sciatic notch is also important. Therefore, sufficient preoperative planning is essential. However, traditional planning methods do not readily provide direct visual and tactile feedback to surgeons. Rapid prototyping (RP) models have provided new opportunities in the preoperative planning of delayed reconstruction of acetabular fractures. We hypothesized that a three-dimensional (3D) skeleton-arterial model would improve both preoperative planning in the management of fractures and arteries and intraoperative assistance during delayed reconstruction of complex acetabular fractures.MethodsEight patients were enrolled in this study. Data on the skeleton and arteries were obtained from computed tomography and angiography scans and used to produce RP models. Preoperative surgical planning and intraoperative assistance were performed using these models as references.ResultsAll 3D skeleton-arterial models were extremely accurate. Reduction and fixation were performed programmatically and smoothly, and management of the SGA was reliably executed according to a thorough preoperative plan. The mean surgical time and intraoperative blood loss were 224.4 min and 1250 ml, respectively. Among the eight patients, four underwent anatomic reduction and five had excellent functional outcomes at the final follow-up. No significant complications occurred.ConclusionsThis 3D skeleton-arterial model is helpful for orthopedists in preoperative planning and intraoperative assistance.

Alignment and mechanics evaluation for a compaction broach stem versus a blade style proximal press fit stem using 3-Dimensional planning

Background: Implants in dentistry are, besides fixed, removable and maxillofacial prosthodontics, one of the reliable possibility to make functional and aesthetic rehabilitation of the edentulism. Surgical and prosthodontic implant complications are often an inattentive consequence of wrong diagnosis, planning, and placement. In this article we present a technique using a highly advanced software program along with a rapid prototyping technology named stereolithography. A planning software for implant placement needs basically the high quality computed tomographic scan of one or both jaws for making accurate preoperative diagnostics and 3D preoperative plan. Later individual drill guide is designed and generated based on both the CT images and the preoperative planning. The patient specific drill guide transfers the virtual planning to the patient’s mouth at time of surgery. Conclusions: The advantages of computer guided implantology are the better prepared surgery with visualisation of critical anatomic structures, assessment of available bone and data about bone quality, increased confidence for the surgeon, deceased operative time, less frequent use of bone grafts, higher quality of collaboration between specialists and prosthetic lab and better communication with patients. Radiographic examination of the operation field for computer guided planning for implant placement is due to high costs justified as the most important information source on the areas to be implanted.

Virtual assisted surgery system in the preoperative planning, teaching, communication between doctors and patients has an important application value. Due to the hardware and computer technology constraints, most of the research on the virtual surgery system based on 3D software model simulation to simulate human tissue. To solve the problem, an assisted system for precise surgery based on medical image computing and VR is designed in this paper. Firstly, this work designed the overall scheme of the system, including function design, hardware design scheme, software design scheme and key technology, starting from the system requirements and feasibility. Secondly, the work studies the key technologies of virtual assistant surgery system, such as the generation of human tissue model and the collision detection. In order to improve the quality of grid generation and remove noise, a tetrahedral mesh generation method based on grid and improved Laplacian smoothing algorithm is adopted in this work. Finally, the modular idea is used, respectively, to start UI and virtual surgery scene construction and interaction, independent units and the overall integration test to ensure that the system is running without errors and fluent, to achieve the original design of virtual assistant surgery system.

To report on preoperative assessment, surgery, and audiologic outcome of the first patient implanted with the bone conduction implant (BCI). The BCI is a bone conduction hearing device with an intact skin solution where the transducer is implanted close to the ear canal opening. By avoiding a percutaneous screw attachment to the skull, the BCI is anticipated to reduce complications associated with the Bone-Anchored Hearing Aid (BAHA) solution. The first patient to receive a BCI was a 42-year-old woman with a unilateral mixed hearing loss due to tympanosclerosis. Preoperative and postoperative cone beam computed tomography and a virtual planning tool for 3D reconstruction were used to optimize and control the position of the BCI in the mastoid. The transducer was placed in a 5-mm deep seating in the mastoid and secured with a titanium bar. Free field tone and speech audiometry were conducted to evaluate the audiologic outcome at baseline (1 month postoperatively) and 1 month after baseline. The BCI was placed in the position according to the preoperative 3D planning. On average, the tone thresholds improved by 30 dB, speech reception thresholds by 25.5 dB and speech signal-to-noise ratio by 9.7 dB. The surgical procedure was considered simple and safe. The BCI can be implanted by a safe and easy surgical procedure. 3D preoperative planning can be helpful to optimize the BCI position. The BCI is a realistic alternative to the BAHA.

PurposeThe aim of this study was to evaluate the accuracy of a patient-specific cutting guide on both coronal and sagittal alignment compared to the pre-operative planning in OWHTO.MethodsTwelve OWHTO on 6 cadaveric specimens were performed by 3 experienced knee surgeons using patient-specific cutting guides based on 3D pre-operative planning. Since the specimens had no major deformities, a fixed correction of 6° on the left and 10° on the right legs were carried out to simulate different scenarios. A pre-operative and post-OWHTO 3D CT scans were performed, and images were superimposed using the dedicated 3D planning software to align their reference axes. A pre-operative planning was performed considering both Medial Proximal Tibial Angle (MPTA) and Posterior Tibial Slope (PTS), and a patient-specific cutting guide was produced. Planned and post-OWHTO MPTA and PTS were evaluated (mean and standard deviation), and Pearson’s correlation coefficient was calculated to assess precision and accuracy of the whole treatment.ResultsA mean correction of 6,1° (SD 1,9°) and 1,2° (SD 1°) was obtained respectively in the coronal plane (MPTA) and in the sagittal plane (PTS). The average difference between planned and post-OWHTO MPTA and PTS was respectively 1,2° (SD 0,6°) and 1,2° (SD 1°) in the sagittal plane (PTS). Pearson’s correlation coefficient demonstrated a good accuracy of the treatment in both coronal and sagittal plane (respectively r=0,95 and r=0,86). No lateral hinge fractures were detected at the post-operative CT scan.ConclusionOWTHO performed with the help of 3D patient specific cutting guide on cadaveric specimens demonstrated good accuracy and reliability in obtaining the planned correction. In vivo studies are necessary to confirm these results and evaluate cost-effectiveness of this system.Level of evidenceLevel IV cadaveric study.

BACKGROUND: Internal fixation of pilon fractures remains challenging despite the development of new technologies in medical imaging and implant design and various scientific investigations on this problem. A key point in therapeutic strategy is preoperative planning. Since the beginning of the twenty-first century, the procedure has changed dramatically from plain radiograph drawing to 3D models and internal fixation simulation in vitro. AIM: This study aimed to evaluate 3D modeling in pilon fracture osteosynthesis preoperative planning. MATERIALS AND METHODS: The study used open, prospective, randomized, and comparative analysis. We analyzed the data of 60 patients with pilon fractures who had undergone surgical treatment for pilon fractures between July 1, 2020, and December 12, 2021, in Moscow City Hospital No. 17. In 30 patients, 3D models were used in preoperative planning, and in another 30 patients, the traditional planning method was performed. The operation time, intraoperation, X-ray dosage, blood loss, fracture reduction quality, and long-term results were analyzed. Additionally, the surgeon’s comfort in applying the 3D model and ease of doctor–patient communication were assessed using questionnaires. RESULTS: Results showed that 3D modeling in pilon fracture osteosynthesis preoperative planning has advantages over traditional preoperative planning. CONCLUSION: Therefore, 3D planning is a promising novel method for distal tibial fracture internal fixation preoperative planning, which provides significant higher degree of fracture anatomy comprehension and facilitates reduction maneuvers and implant positioning.

Three-dimensional corrective osteotomies of complex malunited humeral fractures using patient-specific guides

DigBody®: A new 3D modeling tool for nasal virtual surgery

Cinematic rendering (CR) is based on a new algorithm that creates a photo-realistic three-dimensional (3D) picture from cross-sectional images. Previous studies have shown its positive impact on preoperative planning. To date, CR presentation has only been possible on 2D screens which limited natural 3D perception. To depict CR-hearts spatially, we used mixed-reality technology and mapped corresponding hearts as holograms in 3D space. Our aim was to assess the benefits of CR-holograms in the preoperative planning of cardiac surgery. Including 3D prints allowed a direct comparison of two spatially resolved display methods. Twenty-six patients were recruited between February and September 2019. CT or MRI was used to visualize the patient's heart preoperatively. The surgeon was shown the anatomy in cross-sections on a 2D screen, followed by spatial representations as a 3D print and as a high-resolution hologram. The holographic representation was carried out using mixed-reality glasses (HoloLens®). To create the 3D prints, corresponding structures were segmented to create STL files which were printed out of resin. In 22 questions, divided in 5 categories (3D-imaging effect, representation of pathology, structure resolution, cost/benefit ratio, influence on surgery), the surgeons compared each spatial representation with the 2D method, using a five-level Likert scale. The surgical preparation time was assessed by comparing retrospectively matched patient pairs, using a paired t-test. CR-holograms surpassed 2D-monitor imaging in all categories. CR-holograms were superior to 3D prints in all categories (mean Likert scale 4.4 ± 1.0 vs. 3.7 ± 1.3, P < 0.05). Compared to 3D prints it especially improved the depth perception (4.7 ± 0.7 vs. 3.7 ± 1.2) and the representation of the pathology (4.4 ± 0.9 vs. 3.6 ± 1.2). 3D imaging reduced the intraoperative preparation time (n = 24, 59 ± 23 min vs. 73 ± 43 min, P < 0.05). In conclusion, the combination of an extremely photo-realistic presentation via cinematic rendering and the spatial presentation in 3D space via mixed-reality technology allows a previously unattained level of comprehension of anatomy and pathology in preoperative planning.

Objective: Emissary veins are often neglected in their clinical relevance. However, at the retrosigmoid approach especially during semisitting positions these transosseous venous connections become potentially live threatening. Therefore, knowledge of presence and the configuration of emissary veins is essentially in the preoperative planning. Methods: A total of 200 consecutive patients planned for the retrosigmoid approach, due to cerebellopontine angle pathology, were evaluated by computed tomography in standard technique (5-mm slices) and spiral technique for the posterior fossa (1-mm slices). The presence and size of emissary veins, entry point in the sigmoid sinus, the predilection side, and the visibility in either CT technique were evaluated. Results: Emissary veins were present in 80% of the patients, varying from 0.3 to 4 mm in diameter, whereas 1% (right)and 2% (left) of the patients have more than one emissary vein, respectively. The mean length of the intraosseous course of the vein to the entry point in the sigmoid sinus was 7.6 mm (right side) and 5.1 mm (left side). The study shows that with standard CT technique only emissary veins larger than 1.0mm can be identified and that either entry point in the skull base or sigmoid sinus cannot be securely visualized. On the other hand, spiral technique CT scans visualized emissary veins of 0.3mm with their exact course from the skull to the entry point in the sigmoid sinus. Conclusions: Thin sliced CT scans are inevitable in the preoperative planning of the retrosigmoid approach to identify the presence and the course of emissary veins, reducing unnecessary morbidity during surgery.

Recently, three-dimensional (3D) planning, patient-specific instruments, and navigation system have been developed to improve the accuracy of baseplate placement in reverse shoulder arthroplasty (RSA). The purpose of this study was to evaluate baseplate placement using the navigation system. Sixty-four shoulders in 63 patients who underwent RSA for rotator cuff tear arthropathy or irreparable rotator cuff tears were enrolled. Conventional RSA was performed in 31 shoulders and navigated RSA using pre-operative planning software was performed in 33 shoulders. The use of augmented baseplates, the version and inclination of the baseplate, and screw length were compared between conventional RSA and navigated RSA. Augmented baseplates were used more frequently in navigated RSA than in conventional RSA (20 vs 9 shoulders, p = 0.014). Baseplate alignment was 1.0° (SD 5.1) of retroversion and 2.4° (SD 6.8) of superior inclination in conventional RSA and 0.2° (SD 1.9) of anteversion and 0.3° (SD 1.7) of superior inclination in navigated RSA. Compared with conventional RSA, precision of baseplate version and inclination were higher in navigated RSA (both p < 0.001). Superior, inferior, and posteroinferior screws were significantly longer in navigated RSA than in conventional RSA (p = 0.021, 0.001 and < 0.001, respectively). Precision of superior and inferior screw lengths was significantly higher in navigated RSA than in conventional RSA (both p = 0.001). Our results suggest that adoption of pre-operative planning software increased augmented baseplate use to minimize the glenoid reaming. The navigation system allows placement of the baseplate accurately, according to the pre-operative plan. Furthermore, the navigation system enables monitoring of screw length and direction in real time.