Prediction of jaw opening function after mandibular reconstruction using subject-specific musculoskeletal modelling

BACKGROUND

Mandibular reconstruction patients often suffer abnormalities in the mandibular kinematics. In silico simulations, such as musculoskeletal modelling, can be used to predict post-operative mandibular kinematics. It is important to validate the mandibular musculoskeletal model and analyse the factors influencing its accuracy.

OBJECTIVES

To investigate the jaw opening-closing movements after mandibular reconstruction, as predicted by the subject-specific musculoskeletal model, and the factors influencing its accuracy.

METHODS

Ten mandibular reconstruction patients were enrolled in this study. Cone-beam computed tomography images, mandibular movements, and surface electromyogram signals were recorded preoperatively. A subject-specific mandibular musculoskeletal model was established to predict surgical outcomes using patient-averaged muscle parameter changes as model inputs. Jaw bone geometry was replaced by surgical planning results, and the muscle insertion sites were registered based on the non-rigid iterative closest point method. The predicted jaw kinematic data were validated based on 6-month post-operative measurements. Correlations between the prediction accuracy and patient characteristics (age, pathology and surgical scope) were further analysed.

RESULTS

The root mean square error (RMSE) for lower incisor displacement was 31.4%, and the error for peak magnitude of jaw opening was 4.9 mm. Age, post-operative infection and radiotherapy influenced the prediction accuracy. The amount of masseter detachment showed little correlation with jaw opening.

CONCLUSION

The mandibular musculoskeletal model successfully predicted short-range jaw opening functions after mandibular reconstruction. It provides a novel surgical planning method to predict the risk of developing trismus.

Use of modern three-dimensional imaging models to guide surgical planning for local control of pediatric extracranial solid tumors

INTRODUCTION

In complex pediatric surgical oncology, surgical planning is contingent upon data gathered from preoperative imaging. Three-dimensional (3D) modeling and printing has been shown to be beneficial for adult presurgical planning, though pediatric literature is less robust. The study reviews our institutional experience with the use of 3D image segmentation and printed models in approaching resection of extracranial solid tumors in children.

METHODS

This is a single institutional series from 2021 to 2023. Models were based on computed tomography and magnetic resonance imaging studies, optimized for 3D imaging. The feasibility and creation of the models is reviewed, including specific techniques, software, and printing materials from our institution. Clinical implications for surgical planning are also described, along with detailed preoperative and intraoperative images.

RESULTS

3D modeling and printing was performed for four pediatric patients diagnosed with extracranial solid tumors. Diagnoses included Ewing sarcoma, hepatoblastoma, synovial sarcoma, and osteosarcoma. No intraoperative complications or discrepancies with the preoperative 3D-printed model were noted. No evidence of local recurrence was identified in any patient thus far.

CONCLUSION

Our institutional series demonstrates a wide spectrum of clinical application for 3D modeling and printing technology within pediatric surgical oncology. This technology may aid in surgical planning for both resection and reconstruction, can be applied to a diverse breadth of diagnoses, and may potentially augment patient and/or family education about their condition.

Pre-operative Prolapse Phenotype is Predictive of Surgical Outcome with Minimally Invasive Sacrocolpopexy

BACKGROUND

The gold standard treatment for advanced pelvic organ prolapse is sacrocolpopexy. However, the pre-operative features of prolapse that predict optimal outcomes are unknown.

OBJECTIVES

We aimed to develop a clinical prediction model that uses pre-operative scores on the Pelvic Organ Prolapse Quantification examination to predict outcomes after minimally invasive sacrocolpopexy for stages 2, 3, and 4 uterovaginal prolapse and vaginal vault prolapse.

STUDY DESIGN

A two-institution database of pre- and post-operative variables from 881 cases of minimally invasive sacrocolpopexy was analyzed. Data from patients were analyzed in four groups: stage 2 uterovaginal prolapse, stage 3-4 uterovaginal prolapse, stage 2 vaginal vault prolapse, and stage 3-4 vaginal vault prolapse. Unsupervised machine learning was used to identify clusters and investigate associations between clusters and outcome. The K-means clustering analysis was performed with pre-operative Pelvic Organ Prolapse Quantification points and stratified by prior hysterectomy status. The "optimal" surgical outcome was defined as post-operative Pelvic Organ Prolapse Quantification stage <2. Demographic variables were compared by cluster with Student's t-test and Chi-squared tests. Odds ratios were calculated to determine whether clusters could predict the outcome. Age at surgery, body mass index, and prior prolapse surgery were used for adjusted odds ratios.

RESULTS

Five statistically distinct prolapse clusters (phenotypes C, A, A>P, P, and P>A) were found. These phenotypes reflected the predominant region of prolapse (apical, anterior, or posterior) and whether or not support was preserved in the non-predominant region. Phenotype A (anterior compartment prolapse predominant, posterior support preserved) was found in all four groups of patients and was considered the reference in analysis. In 111 patients with stage 2 uterovaginal prolapse, phenotypes A and A>P (greater anterior prolapse than posterior prolapse) were found, and patients with phenotype A were more likely than those with phenotype A>P to have an optimal surgical outcome. In 401 patients with stage 3-4 uterovaginal prolapse, phenotypes C (apical compartment predominant, prolapse in all compartments), A, and A>P were found, and patients with phenotype A>P were more likely than those with phenotype A to have ideal surgical outcome. In 72 patients with stage 2 vaginal vault prolapse, phenotypes A, A>P, and P (posterior compartment predominant, anterior support preserved) were found, and those with phenotype A>P were less likely to have an ideal outcome than patients with phenotype A. In 297 patients with stage 3-4 vaginal vault prolapse, phenotypes C, A, and P>A (prolapse greater in posterior compartment than in anterior) were found, but there were no significant differences in rate of ideal outcome between phenotypes.

CONCLUSIONS

Five anatomic phenotypes based on pre-operative Pelvic Organ Prolapse Quantification scores were present in patients with stages 2 and 3-4 uterovaginal prolapse and vaginal vault prolapse. These phenotypes are predictive of surgical outcome after minimally invasive sacrocolpopexy. Further work needs to confirm the presence and predictive nature of these phenotypes. Additionally, whether the phenotypes represent a progression of prolapse or discrete prolapse presentations resulting from different anatomic and life course risk profiles is unknown. These phenotypes may be useful in surgical counseling and planning.

A System for Mixed-Reality Holographic Overlays of Real-Time Rendered 3D-Reconstructed Imaging Using a Video Pass-through Head-Mounted Display-A Pathway to Future Navigation in Chest Wall Surgery

Background: Three-dimensional reconstructions of state-of-the-art high-resolution imaging are progressively being used more for preprocedural assessment in thoracic surgery. It is a promising tool that aims to improve patient-specific treatment planning, for example, for minimally invasive or robotic-assisted lung resections. Increasingly available mixed-reality hardware based on video pass-through technology enables the projection of image data as a hologram onto the patient. We describe the novel method of real-time 3D surgical planning in a mixed-reality setting by presenting three representative cases utilizing volume rendering. Materials: A mixed-reality system was set up using a high-performance workstation running a video pass-through-based head-mounted display. Image data from computer tomography were imported and volume-rendered in real-time to be customized through live editing. The image-based hologram was projected onto the patient, highlighting the regions of interest. Results: Three oncological cases were selected to explore the potentials of the mixed-reality system. Two of them presented large tumor masses in the thoracic cavity, while a third case presented an unclear lesion of the chest wall. We aligned real-time rendered 3D holographic image data onto the patient allowing us to investigate the relationship between anatomical structures and their respective body position. Conclusions: The exploration of holographic overlay has proven to be promising in improving preprocedural surgical planning, particularly for complex oncological tasks in the thoracic surgical field. Further studies on outcome-related surgical planning and navigation should therefore be conducted. Ongoing technological progress of extended reality hardware and intelligent software features will most likely enhance applicability and the range of use in surgical fields within the near future.

The Role of Three-Dimensional Modeling to Improve Comprehension of Liver Anatomy and Tumor Characteristics for Medical Students and Surgical Residents

OBJECTIVE

Studying liver anatomy can be challenging for medical students and surgical residents due to its complexity. Three-dimensional visualization technology (3DVT) allows for a clearer and more precise view of liver anatomy. We sought to assess how 3DVT can assist students and surgical residents comprehend liver anatomy.

DESIGN

Data from 5 patients who underwent liver resection for malignancy at our institution between September 2020 and April 2022 were retrospectively reviewed and selected following consensus among the investigators. Participants were required to complete an online survey to investigate their understanding of tumor characteristics and vascular variations based on patients' computed tomography (CT) and 3DVT.

SETTING

The study was carried out at the General and Hepato-Biliary Surgery Department of the University of Verona.

PARTICIPANTS

Among 32 participants, 13 (40.6%) were medical students, and 19 (59.4%) were surgical residents.

RESULTS

Among 5 patients with intrahepatic lesions, 4 patients (80.0%) had at least 1 vascular variation. Participants identified number and location of lesions more correctly when evaluating the 3DVT (84.6% and 80.9%, respectively) compared with CT scans (61.1% and 64.8%, respectively) (both p ≤ 0.001). The identification of any vascular variations was more challenging using the CT scans, with only 50.6% of correct answers compared with 3DVT (72.2%) (p < 0.001). Compared with CT scans, 3DVT led to a 23.5%, 16.1%, and 21.6% increase in the correct definition of number and location of lesions, and vascular variations, respectively. 3DVT allowed for a decrease of 50.8 seconds (95% CI 23.6-78.0) in the time needed to answer the questions. All participants agreed on the usefulness of 3DVT in hepatobiliary surgery.

CONCLUSIONS

The 3DVT facilitated a more precise preoperative understanding of liver anatomy, tumor location and characteristics.

Evaluating Pelvic Tilt Using the Pelvic Antero-Posterior Projection Images: A Systematic Review

BACKGROUND

Pelvic tilt (PT) is a routinely evaluated parameter in hip and spine surgeries, and is usually measured on a sagittal pelvic radiograph. This may not always be feasible due to limitations such as landmark visibility, pelvic anomaly, and hardware presence. Tremendous efforts have been dedicated to using pelvic antero-posterior (AP) radiographs for assessing sagittal PT. Thus, this systematic review aimed to collect these methods and evaluate their performances.

METHODS

Two independent reviewers searched the PubMed, Ovid, Cochrane, and Web of Science databases in June 2023 with backward reference trailing (Google Scholar archive). There were 30 studies recruited. Risk of bias was assessed using the prediction model risk of bias assessment tool. The relevant data were tabulated in a standardized form for evaluating either the absolute PT or relative PT. Disagreement was resolved by discussing with the senior author.

RESULTS

There were 19 parameters from pelvic AP projection images involved, with 4 studies which used artificial intelligence, eyeball, or statistical shape method not involving a specific parameter. In comparing the PT values from pelvic sagittal images with those extrapolated from antero-posterior projection images, the highest correlation coefficient was found to be 0.91. The mean absolute difference (error) was 2.6°, with a maximum error reaching 10.9°. Most studies supported the feasibility of using AP parameters to calculate changes in PT.

CONCLUSIONS

No individual AP parameter was found to precisely estimate absolute PT. However, relative PT can be derived by evaluating serial AP radiographs of a patient in varying postures, employing any AP parameters.

Experimental research based on robot-assisted surgery: Lower limb fracture reduction surgery planning navigation system

Background and Aims

Lower extremity fracture reduction surgery is a key step in the treatment of lower extremity fractures. How to ensure high precision of fracture reduction while reducing secondary trauma during reduction is a difficult problem in current surgery.

Methods

First, segmentation and three-dimensional reconstruction are performed based on fracture computed tomography images. A cross-sectional point cloud extraction algorithm based on the normal filtering of the long axis of the bone is designed to obtain the cross-sectional point clouds of the distal bone and the proximal bone, and the optimal reset target pose of the broken bone is obtained by using the iterative closest point algorithm. Then, the optimal reset sequence of reset parameters was determined, combined with the broken bone collision detection algorithm, a surgical planning algorithm for lower limb fracture reset was proposed, which can effectively reduce the reset force while ensuring the accuracy of the reset process without collision.

Results

The average error of the reduction of the model bone was within 1.0 mm. The reduction operation using the planning and navigation system of lower extremity fracture reduction surgery can effectively reduce the reduction force. At the same time, it can better ensure the smooth change of the reduction force.

Conclusion

Planning and navigation system of lower extremity fracture reduction surgery is feasible and effective.

Cinematic Rendering of Pancreatic Neuroendocrine Tumours: Opportunities for Clinical Implementation: Part 2: Preoperative Planning and Evaluation of Metastatic Disease

Pancreatic neuroendocrine tumours (PNETs) are a rare subset of pancreatic tumours that have historically comprised up to 3% of all clinically detected pancreatic tumours. In recent decades, however, advancements in imaging have led to an increased incidental detection rate of PNETs and imaging has played an increasingly central role in the initial diagnostics and surgical planning of these tumours. Cinematic rendering (CR) is a 3D post-processing technique that generates highly photorealistic images through more realistically modelling the path of photons through the imaged volume. This allows for more comprehensive visualization, description, and interpretation of anatomical structures. In this 2-part review article, we present the first description of the various CR appearances of PNETs in the reported literature while providing commentary on the unique clinical opportunities afforded by the adjunctive utilization of CR in the workup of these rare tumours. This second instalment focuses on the applications of CR in optimizing preoperative planning of PNETs.

Multidisciplinary Advanced Surgical Planning for Slide Tracheoplasty Using 3D-Printed Models

OBJECTIVE

The objective of this study was to develop and assess multidisciplinary advanced surgical planning (ASP) sessions using three dimensional (3D) printed models for cervicothoracic slide tracheoplasty (CST). We hypothesized that these sessions would improve surgeon confidence, streamline intraoperative planning, and highlight the utility of 3D modeling.

METHODS

3D-printed patient-specific trachea models were used in pre-operative ASP sessions consisting of a multidisciplinary case discussion and hands-on slide tracheoplasty simulation. Participants completed a survey rating realism, utility, impact on the final surgical plan, and pre- and post-session confidence. Statistical analysis was performed via Wilcoxon and Kruskal-Wallis tests.

RESULTS

Forty-eight surveys were collected across nine sessions and 27 different physicians. On a 5-point Likert scale, models were rated as "very realistic", "very useful" (both median of 4, IQR 3-4 and 4-5, respectively). Overall confidence increased by 1.4 points (+/- 0.7, p < 0.0001), with the largest change seen in those with minimal prior slide tracheoplasty experience (p = 0.005). Participants felt that the sessions "strongly" impacted their surgical plan or anticipated performance (median 4, IQR 4-5), regardless of training level or experience.

CONCLUSION

3D-printed patient-specific models were successfully implemented in ASP sessions for CST. Models were deemed very realistic and very useful by surgeons across multiple specialties and training levels. Surgical planning sessions also strongly impacted the final surgical plan and increased surgeon confidence for CST.

LEVEL OF EVIDENCE

IV Laryngoscope, 2024.

Partnering With Technology: Advancing Laparoscopy With Artificial Intelligence and Machine Learning

Artificial intelligence (AI) and machine learning (ML) have emerged as transformative technologies in optimizing laparoscopic surgery, offering innovative solutions to enhance surgical precision, efficiency, and safety. This editorial explores the potential role of AI/ML across the surgical continuum, including preoperative optimization, intraoperative assistance, and postoperative care. It outlines the benefits of laparoscopic surgery compared to traditional open procedures and identifies current challenges such as technical difficulty and human error. The editorial discusses how AI and ML technologies can address these challenges, including patient selection and risk stratification, surgical planning and simulation, and personalized medicine approaches. Moreover, it examines the role of AI/ML in intraoperative assistance, such as instrument tracking and guidance, real-time tissue analysis, and the detection of potential complications. Postoperative care and follow-up are also explored, highlighting the potential of AI/ML in monitoring patient recovery, predicting and preventing complications, and tailoring rehabilitation plans. Ethical concerns surrounding data privacy and security, the lack of transparency in decision-making, potential job displacement, and regulatory frameworks are discussed as challenges to the widespread adoption of AI/ML in laparoscopic surgery. Finally, potential areas for further research and exploration are outlined, emphasizing interdisciplinary collaboration and the need for transparent and accountable AI systems. Overall, this editorial provides insights into the challenges and opportunities in harnessing AI/ML technologies to optimize laparoscopic surgery and improve patient outcomes.

Comparative study of biomodels manufactured using 3D printing techniques for surgical planning and medical training

OBJECTIVES

To obtain 3D printed bone models with a haptic sensation similar to that of the real bone, which will help the surgeon to learn and improve based on practice.

METHODS

From computed tomography, 3 digital anatomical models of the human proximal femur were created and, by modifying the printing parameters, both cortical and trabecular tissues were simulated, which were combined in a different cortico-cancellous interface depending on the bone segment. The 3 equivalent models obtained were compared with a commercial Sawbone synthetic model and subjected to a series of blind surgical practice trials performed by 5 TOC specialists from a hospital, each of them with different degrees of expertise. A statistical analysis of the qualitative data collected based on the Wilcoxon test, the Spearman correlation matrix, and the Validity Ratio Coefficient was performed.

RESULTS

The deviations observed in the dimensional study are less than 0.2 millimeter, which confirms the validity of the 3DP-FFF technology to geometrically recreate personalized biomodels with high anatomical precision.

CONCLUSIONS

The reproductions obtained have given rise to a reliable method that professionals can refine to plan operations with the consequent reduction of time and risks for the patient, as well as for medical training.

Superficial Temporal Artery Island Flap Combined With Laser Hair Removal for Inadequate Skin Expansion Following Tissue Expansion: A Case Report of Congenital Melanocytic Nevus of the Forehead in an Adult

Tissue expansion is a handy reconstructive technique for the head and neck region; however, its implementation requires careful planning and surgical experience. If tissue expansion is inadequate, forced closure results in wound tension and risks complications, such as postoperative deformity, wide scarring, and wound dehiscence. We report a case of adult forehead melanocytic nevus excision using a tissue expander (TE) where complications caused by insufficient tissue expansion were avoided by creating a flap using a dog ear. The patient was a male in his 20s who underwent surgery with a TE for a congenital melanocytic nevus sized 15 × 10 cm on the left forehead. Resection was performed by tissue expansion using two TEs; however, simple advancement flaps led to excessive wound tension, risk of elevation of the eyebrow on the affected side, and postoperative scarring. Hence, a superficial temporal artery fasciocutaneous island flap with left superficial temporal vessels as a pedicle was raised at the dog ear and moved to the site of strong tension, and the wound was closed without difficulty. Although postoperative laser hair removal was required, both the appearance and functional results were satisfactory. Using anatomical flaps obtained from the surroundings during tissue expansion helps avoid complications associated with forced wound closure.

Biomimicking Atherosclerotic Vessels: A Relevant and (Yet) Sub-Explored Topic

Atherosclerosis represents the etiologic source of several cardiovascular events, including myocardial infarction, cerebrovascular accidents, and peripheral artery disease, which remain the leading cause of mortality in the world. Numerous strategies are being delineated to revert the non-optimal projections of the World Health Organization, by both designing new diagnostic and therapeutic approaches or improving the interventional procedures performed by physicians. Deeply understanding the pathological process of atherosclerosis is, therefore, mandatory to accomplish improved results in these trials. Due to their availability, reproducibility, low expensiveness, and rapid production, biomimicking physical models are preferred over animal experimentation because they can overcome some limitations, mainly related to replicability and ethical issues. Their capability to represent any atherosclerotic stage and/or plaque type makes them valuable tools to investigate hemodynamical, pharmacodynamical, and biomechanical behaviors, as well as to optimize imaging systems and, thus, obtain meaningful prospects to improve the efficacy and effectiveness of treatment on a patient-specific basis. However, the broadness of possible applications in which these biomodels can be used is associated with a wide range of tissue-mimicking materials that are selected depending on the final purpose of the model and, consequently, prioritizing some materials' properties over others. This review aims to summarize the progress in fabricating biomimicking atherosclerotic models, mainly focusing on using materials according to the intended application.

Gaze Patterns of Normal and Microtia Ears Pre- and Post-Reconstruction

OBJECTIVES

To understand attentional preferences for normal and microtia ears.

METHODS

Eye-tracking technology was used to characterize gaze preferences. A total of 71 participants viewed images of 5 patients with unilateral microtia. Profile images of patient faces and isolated ears including normal, microtia, and post-reconstruction microtia ears were shown. Total time of fixation in predefined areas of interest (AOI) was measured. Inferential statistics were used to assess significance of fixation differences between AOIs within and between facial or auricular features.

RESULTS

The ear received most visual attention in lateral view of the face (1.91 s, 1.66-2.16 s) [mean, 95% CI], followed by features of the "central triangle"-the eyes (1.26 s, 1.06-1.46), nose (0.48 s, 0.38-0.58), and mouth (0.15 s, 0.15-0.20). In frontal view, microtia ears received less attention following surgical reconstruction (0.74 s vs. 0.4 s, p < 0.001). The concha was the most attended feature for both normal (2.97 s, 2.7-3.23) and reconstructed microtia ears (1.87 s, 1.61-2.13). Scars on reconstructed ears altered the typical visual scanpath.

CONCLUSION

The ear is an attentional gaze landmark of the face. Attention to microtia ears, both pre- and post-reconstruction, differs from gaze patterns of normal ears. The concha was the most attended to subunit of the ear. Attentional gaze may provide an unbiased method to determine what is important in reconstructive surgery.

LEVEL OF EVIDENCE

N/A Laryngoscope, 2024.

The Integration of 3D Virtual Reality and 3D Printing Technology as Innovative Approaches to Preoperative Planning in Neuro-Oncology

Our study explores the integration of three-dimensional (3D) virtual reality (VR) and 3D printing in neurosurgical preoperative planning. Traditionally, surgeons relied on two-dimensional (2D) imaging for complex neuroanatomy analyses, requiring significant mental visualization. Fortunately, nowadays advanced technology enables the creation of detailed 3D models from patient scans, utilizing different software. Afterwards, these models can be experienced through VR systems, offering comprehensive preoperative rehearsal opportunities. Additionally, 3D models can be 3D printed for hands-on training, therefore enhancing surgical preparedness. This technological integration transforms the paradigm of neurosurgical planning, ensuring safer procedures.

Three-dimensional analysis of reconstructed skulls using three different open-source software versus commercial software

This study aimed to compare the 3D skull models reconstructed from computed tomography (CT) images using three different open-source software with a commercial software as a reference. The commercial Mimics v17.0 software was used to reconstruct the 3D skull models from 58 subjects. Next, two open-source software, MITK Workbench 2016.11, 3D Slicer 4.8.1 and InVesalius 3.1 were used to reconstruct the 3D skull models from the same subjects. All four software went through similar steps in 3D reconstruction process. The 3D skull models from the commercial and open-source software were exported in standard tessellation language (STL) format into CloudCompare v2.8 software and superimposed for geometric analyses. Hausdorff distance (HD) analysis demonstrated the average points distance of Mimics versus MITK was 0.25 mm. Meanwhile, for Mimics versus 3D Slicer and Mimics versus InVesalius, there was almost no differences between the two superimposed 3D skull models with average points distance of 0.01 mm. Based on Dice similarity coefficient (DSC) analysis, the similarity between Mimics versus MITK, Mimics versus 3D Slicer and Mimics versus InVesalius were 94.1, 98.8 and 98.3%, respectively. In conclusion, this study confirmed that the alternative open-source software, MITK, 3D Slicer and InVesalius gave comparable results in 3D reconstruction of skull models compared to the commercial gold standard Mimics software. This open-source software could possibly be used for pre-operative planning in cranio-maxillofacial cases and for patient management in the hospitals or institutions with limited budget.

Mixed Reality for Cranial Neurosurgical Planning: A Single-Center Applicability Study With the First 107 Subsequent Holograms

BACKGROUND AND OBJECTIVES

Mixed reality (MxR) benefits neurosurgery by improving anatomic visualization, surgical planning and training. We aim to validate the usability of a dedicated certified system for this purpose.

METHODS

All cases prepared with MxR in our center in 2022 were prospectively collected. Holographic rendering was achieved using an incorporated fully automatic algorithm in the MxR application, combined with contrast-based semiautomatic rendering and/or manual segmentation where necessary. Hologram segmentation times were documented. Visualization during surgical preparation (defined as the interval between finalized anesthesiological induction and sterile draping) was performed using MxR glasses and direct streaming to a side screen. Surgical preparation times were compared with a matched historical cohort of 2021. Modifications of the surgical approach after 3-dimensional (3D) visualization were noted. Usability was assessed by evaluating 7 neurosurgeons with more than 3 months of experience with the system using a Usefulness, Satisfaction and Ease of use (USE) questionnaire.

RESULTS

One hundred-seven neurosurgical cases prepared with a 3D hologram were collected. Surgical indications were oncologic (63/107, 59%), cerebrovascular (27/107, 25%), and carotid endarterectomy (17/107, 16%). Mean hologram segmentation time was 39.4 ± 20.4 minutes. Average surgical preparation time was 48.0 ± 17.3 minutes for MxR cases vs 52 ± 17 minutes in the matched 2021 cohort without MxR (mean difference 4, 95% CI 1.7527-9.7527). Based on the 3D hologram, the surgical approach was modified in 3 cases. Good usability was found by 57% of the users.

CONCLUSION

The perioperative use of 3D holograms improved direct anatomic visualization while not significantly increasing intraoperative surgical preparation time. Usability of the system was adequate. Further technological development is necessary to improve the automatic algorithms and reduce the preparation time by circumventing manual and semiautomatic segmentation. Future studies should focus on quantifying the potential benefits in teaching, training, and the impact on surgical and functional outcomes.

Rod Angulation Relationship with Thoracic Kyphosis after Adolescent Idiopathic Scoliosis Posterior Instrumentation

INTRODUCTION

Surgery to correct spinal deformities in scoliosis involves the use of contoured rods to reshape the spine and correct its curvatures. It is crucial to bend these rods appropriately to achieve the best possible correction. However, there is limited research on how the rod bending process relates to spinal shape in adolescent idiopathic scoliosis surgery.

METHODS

A retrospective study was conducted using a prospective multicenter scoliosis database. This study included adolescent idiopathic scoliosis patients from the database who underwent surgery with posterior instrumentation covering the T4 to T12 segments. Standing global spine X-rays were used in the analysis. The sagittal Cobb angles between T5 and T11 were measured on the spine. Additionally, the curvature of the rods between T5 and T11 was measured using the tangent method. To assess the relationship between these measurements, the difference between the dorsal kyphosis (TK) and the rod kyphosis (RK) was calculated (ΔK = TK - RK). This study aimed to analyze the correlation between ΔK and various patient characteristics. Both descriptive and statistical analyses were performed to achieve this goal.

RESULTS

This study encompassed a cohort of 99 patients, resulting in a total of 198 ΔK measurements for analysis. A linear regression analysis was conducted, revealing a statistically significant positive correlation between the kyphosis of the rods and that of the spine (r = 0.77, p = 0.0001). On average, the disparity between spinal and rod kyphosis averaged 5.5°. However, it is noteworthy that despite this modest mean difference, there was considerable variability among the patients. In particular, in 84% of cases, the concave rod exhibited less kyphosis than the spine, whereas the convex rod displayed greater kyphosis than the spine in 64% of cases. It was determined that the primary factor contributing to the flattening of the left rod was the magnitude of the coronal Cobb angle, both before and after the surgical procedure. These findings emphasize the importance of considering individual patient characteristics when performing rod bending procedures, aiming to achieve the most favorable outcomes in corrective surgery.

CONCLUSIONS

Although there is a notable and consistent correlation between the curvature of the spine and the curvature of the rods, it is important to acknowledge the substantial heterogeneity observed in this study. This heterogeneity suggests that individual patient factors play a significant role in shaping the outcome of spinal corrective surgery. Furthermore, this study highlights that more severe spinal curvatures in the frontal plane have an adverse impact on the shape of the rods in the sagittal plane. In other words, when the scoliosis curve is more pronounced in the frontal plane, it tends to influence the way the rods are shaped in the sagittal plane. This underscores the complexity of spinal deformities and the need for a tailored approach in surgical interventions to account for these variations among patients.

Automated calculation of ontology-based planning proposals: An application in reconstructive oral and maxillofacial surgery

BACKGROUND

Structured modelling of surgical knowledge and its automated processing is still challenging. The aim of this work is to introduce a novel approach for automated calculation of ontology-based planning proposals in mandibular reconstruction and conduct a feasibility study.

METHODS

The presented approach is composed of an RDF(S) ontology, a 3D mandible template and a calculator-optimiser algorithm to automatically calculate reconstruction proposals with fibula grafts. To validate the viability of the approach, a feasibility study was conducted on 164 simulated mandibular reconstructions.

RESULTS

The ontology defines 244 different reconstruction variants and 80 analyses for optimization. In 146 simulated cases, a proposal could be automatically calculated (average time 8.79 ± 4.03 s). The assessments of the proposals by three clinical experts indicate the viability of the approach.

CONCLUSIONS

Due to the modular separation between computational logic and domain knowledge, the developed concepts can be easily maintained, reused and adapted for other applications.

Mixed Reality and Artificial Intelligence: A Holistic Approach to Multimodal Visualization and Extended Interaction in Knee Osteotomy

OBJECTIVE

Recent advancements in augmented reality led to planning and navigation systems for orthopedic surgery. However little is known about mixed reality (MR) in orthopedics. Furthermore, artificial intelligence (AI) has the potential to boost the capabilities of MR by enabling automation and personalization. The purpose of this work is to assess Holoknee prototype, based on AI and MR for multimodal data visualization and surgical planning in knee osteotomy, developed to run on the HoloLens 2 headset.

METHODS

Two preclinical test sessions were performed with 11 participants (eight surgeons, two residents, and one medical student) executing three times six tasks, corresponding to a number of holographic data interactions and preoperative planning steps. At the end of each session, participants answered a questionnaire on user perception and usability.

RESULTS

During the second trial, the participants were faster in all tasks than in the first one, while in the third one, the time of execution decreased only for two tasks ("Patient selection" and "Scrolling through radiograph") with respect to the second attempt, but without statistically significant difference (respectively [Formula: see text] = 0.14 and [Formula: see text] = 0.13, [Formula: see text]). All subjects strongly agreed that MR can be used effectively for surgical training, whereas 10 (90.9%) strongly agreed that it can be used effectively for preoperative planning. Six (54.5%) agreed and two of them (18.2%) strongly agreed that it can be used effectively for intraoperative guidance.

DISCUSSION/CONCLUSION

In this work, we presented Holoknee, the first holistic application of AI and MR for surgical planning for knee osteotomy. It reported promising results on its potential translation to surgical training, preoperative planning, and surgical guidance. Clinical and Translational Impact Statement - Holoknee can be helpful to support surgeons in the preoperative planning of knee osteotomy. It has the potential to impact positively the training of the future generation of residents and aid surgeons in the intraoperative stage.

Collaborative Virtual Reality Real-Time 3D Image Editing for Chest Wall Resections and Reconstruction Planning

The integration of extended reality (XR) technologies into health care procedures presents transformative opportunities, particularly in surgical processes. This study delves into the utilization of virtual reality (VR) for preoperative planning related to chest wall resections in thoracic surgery. Leveraging the capabilities of 3-dimensional (3D) imaging, real-time visualization, and collaborative VR environments, surgeons gain enhanced anatomical insights and can develop predictive surgical strategies. Two clinical cases highlighted the effectiveness of this approach, showcasing the potential for personalized and intricate surgical planning. The setup provides an immersive, dynamic representation of real patient data, enabling collaboration among teams from separate locations. While VR offers enhanced interactive and visualization capabilities, preliminary evidence suggests it may support more refined preoperative strategies, potentially influence postoperative outcomes, and optimize resource management. However, its comparative advantage over traditional methods needs further empirical validation. Emphasizing the potential of XR, this exploration suggests its broad implications in thoracic surgery, especially when dealing with complex cases requiring multidisciplinary collaboration in the immersive virtual space, often referred to as the metaverse. This innovative approach necessitates further examination, marking a shift toward future surgical preparations. In this article, we sought to demonstrate the technique of an immersive real-time volume-rendered collaborative VR-planning tool using exemplary case studies in chest wall surgery.

A Computational Pipeline for Patient-Specific Prediction of the Postoperative Mitral Valve Functional State

While mitral valve (MV) repair remains the preferred clinical option for mitral regurgitation (MR) treatment, long-term outcomes remain suboptimal and difficult to predict. Furthermore, pre-operative optimization is complicated by the heterogeneity of MR presentations and the multiplicity of potential repair configurations. In the present work, we established a patient-specific MV computational pipeline based strictly on standard-of-care pre-operative imaging data to quantitatively predict the post-repair MV functional state. First, we established human mitral valve chordae tendinae (MVCT) geometric characteristics obtained from five CT-imaged excised human hearts. From these data, we developed a finite-element model of the full patient-specific MV apparatus that included MVCT papillary muscle origins obtained from both the in vitro study and the pre-operative three-dimensional echocardiography images. To functionally tune the patient-specific MV mechanical behavior, we simulated pre-operative MV closure and iteratively updated the leaflet and MVCT prestrains to minimize the mismatch between the simulated and target end-systolic geometries. Using the resultant fully calibrated MV model, we simulated undersized ring annuloplasty (URA) by defining the annular geometry directly from the ring geometry. In three human cases, the postoperative geometries were predicted to 1 mm of the target, and the MV leaflet strain fields demonstrated close agreement with noninvasive strain estimation technique targets. Interestingly, our model predicted increased posterior leaflet tethering after URA in two recurrent patients, which is the likely driver of long-term MV repair failure. In summary, the present pipeline was able to predict postoperative outcomes from pre-operative clinical data alone. This approach can thus lay the foundation for optimal tailored surgical planning for more durable repair, as well as development of mitral valve digital twins.

Bone density optimized pedicle screw insertion

Background: Spinal fusion is the most common surgical treatment for the management of degenerative spinal disease. However, complications such as screw loosening lead to painful pseudoarthrosis, and are a common reason for revision. Optimization of screw trajectories to increase implant resistance to mechanical loading is essential. A recent optimization method has shown potential for determining optimal screw position and size based on areas of high bone elastic modulus (E-modulus). Aim: The aim of this biomechanical study was to verify the optimization algorithm for pedicle screw placement in a cadaveric study and to quantify the effect of optimization. The pull-out strength of pedicle screws with an optimized trajectory was compared to that of a traditional trajectory. Methods: Twenty-five lumbar vertebrae were instrumented with pedicle screws (on one side, the pedicle screws were inserted in the traditional way, on the other side, the screws were inserted using an optimized trajectory). Results: An improvement in pull-out strength and pull-out strain energy of the optimized screw trajectory compared to the traditional screw trajectory was only observed for E-modulus values greater than 3500 MPa cm3. For values of 3500 MPa cm3 or less, optimization showed no clear benefit. The median screw length of the optimized pedicle screws was significantly smaller than the median screw length of the traditionally inserted pedicle screws, p < 0.001. Discussion: Optimization of the pedicle screw trajectory is feasible, but seems to apply only to vertebrae with very high E-modulus values. This is likely because screw trajectory optimization resulted in a reduction in screw length and therefore a reduction in the implant-bone interface. Future efforts to predict the optimal pedicle screw trajectory should include screw length as a critical component of potential stability.

White matter tracts contribute selectively to cognitive functioning in patients with glioma

Objective

The functional organization of white matter (WM) tracts is not well characterized, especially in patients with intrinsic brain tumors where complex patterns of tissue injury, compression, and neuroplasticity may be present. This study uses diffusion tensor imaging (DTI) to investigate the relationships between WM tract disruption and cognitive deficits in glioma patients.

Methods

Seventy-nine patients with glioma underwent preoperative DTI and neuropsychological testing. Thirteen WM tracts were reconstructed bilaterally. Fractional anisotropy and streamline number were obtained for each tract as indices of connectivity. Univariate regression models were used to model the association between WM tract connectivity and neuropsychological outcomes.

Results

Glioma patients exhibited variable injury to WM tracts and variable cognitive deficits on validated neuropsychological tests. We identified 16 age-adjusted associations between WM tract integrity and neuropsychological function. The left inferior frontal-occipital fasciculus (IFOF) predicted list learning and dominant-hand fine motor dexterity. The right IFOF predicted non-dominant-hand fine motor dexterity and visuospatial index scores. The left inferior longitudinal fasciculus (ILF) predicted immediate memory list learning and index scores. The right ILF predicted non-dominant-hand fine motor dexterity and backward digit span scores. The left superior longitudinal fasciculus (SLF) I predicted processing speed. The left SLF III predicted list learning, immediate memory index scores, phonemic fluency, and verbal abstract reasoning. The left cingulum predicted processing speed. The right anterior AF predicted verbal abstract reasoning.

Conclusion

WM tract disruption predicts cognitive dysfunction in glioma patients. By improving knowledge of WM tract organization, this analysis may guide maximum surgical resection and functional preservation in glioma patients.

Three-Dimensional Customized Imaging Reconstruction for Urological Surgery: Diffusion and Role in Real-Life Practice from an International Survey

Despite the arising interest in three-dimensional (3D) reconstruction models from 2D imaging, their diffusion and perception among urologists have been scarcely explored. The aim of the study is to report the results of an international survey investigating the use of such tools among urologists of different backgrounds and origins. Beyond demographics, the survey explored the degree to which 3D models are perceived to improve surgical outcomes, the procedures mostly making use of them, the settings in which those tools are mostly applied, the surgical steps benefiting from 3D reconstructions and future perspectives of improvement. One hundred responders fully completed the survey. All levels of expertise were allowed; more than half (53%) were first surgeons, and 59% had already completed their training. Their main application was partial nephrectomy (85%), followed by radical nephrectomy and radical prostatectomy. Three-dimensional models are mostly used for preoperative planning (75%), intraoperative consultation and tailoring. More than half recognized that 3D models may highly improve surgical outcomes. Despite their recognized usefulness, 77% of responders use 3D models in less than 25% of their major operations due to costs or the extra time taken to perform the reconstruction. Technical improvements and a higher availability of the 3D models will further increase their role in surgical and clinical daily practice.

Performance evaluation of an AI-based preoperative planning software application for automatic selection of pedicle screws based on computed tomography images

Introduction

Recent neurosurgical applications based on artificial intelligence (AI) have demonstrated its potential in surgical planning and anatomical measurement. We aimed to evaluate the performance of an AI planning software application on screw length/diameter selection and insertion accuracy in comparison with freehand surgery.

Methods

A total of 45 patients with 208 pedicle screw placements on thoracolumbar segments were included in this analysis. The novel AI planning software was developed based on a deep learning model. AI-based pedicle screw placements were selected on the basis of preoperative computed tomography (CT) data, and freehand surgery screw placements were observed based on postoperative CT data. The performance of AI pedicle screw placements was evaluated on the components of screw length, diameter, and Gertzbein grade in comparison with the results achieved by freehand surgery.

Results

Among 208 pedicle screw placements, the average screw length/diameters selected by the AI model and used in freehand surgery were 48.65 ± 5.99 mm/7.39 ± 0.42 mm and 44.78 ± 2.99 mm/6.1 ± 0.27 mm, respectively. Among AI screw placements, 85.1% were classified as Gertzbein Grade A (no cortical pedicle breach); among free-hand surgery placements, 64.9% were classified as Gertzbein Grade A.

Conclusion

The novel AI planning software application could provide an accessible and safe pedicle screw placement strategy in comparison with traditional freehand pedicle screw placement strategies. The choices of pedicle screw dimensional parameters made by the model, including length and diameter, may provide potential inspiration for real clinical discretion.

Enhancing surgical planning of distal splenopancreatectomy through 3D printed models: a case report

The complex anatomy of the peripancreatic region was a challenge to many surgeons in the past. Up until recently, the only way to prepare and plan a surgery was through the use of traditional 2D images, obtained via computed tomography or magnetic resonance imaging. Recently, the advantages in the field of 3D printing (also called additive manufacturing, or rapid prototyping) allowed the creation of replicas of the patient's anatomy which is to be used for preoperative planning and visual reference. We present the case of a 46-y.o. patient with a distal pancreatic lesion requiring a distal splenopancreatectomy, who benefited from the use of 3D printing technology. No intraoperative or postoperative complications were encountered, while the created model was used to plan and perform the needed resection.

The use of AVF.SIM system for the surgical planning of arteriovenous fistulae in routine clinical practice

BACKGROUND

The number of patients treated with hemodialysis (HD) in Europe is more than half a million and this number increases annually. The arteriovenous fistula (AVF) is the vascular access (VA) of first choice, but the clinical outcome is still poor. A consistent number of AVFs fails to reach the desired blood flow rate for HD treatment, while some have too high flow and risk for cardiac complications. Despite the skill of the surgeons and the possibility to use Ultrasound investigation for mapping arm vasculature, it is still not possible to predict the blood flow volume that will be obtained after AVF maturation.

METHODS

We evaluated the potential of using a computational model (AVF.SIM) to predict the blood flow volume that will be achieved after AVF maturation, within a multicenter international clinical investigation aimed at assessing AVF.SIM predictive power. The study population included 231 patients, with data on AVF maturation in 124 patients, and on long-term primary patency in 180 patients.

RESULTS

At 1 year of follow-up, about 60% of AVFs were still patent, with comparable primary patency in proximal and distal anastomosis. The correlation between predicted and measured blood flow volume in the brachial artery at 40 days after surgery was statistically significant, with an overall correlation coefficient of 0.58 (p < 0.001). The percent difference between measured and predicted brachial blood flow 40 days after surgery was less than 30% in 72% of patients investigated.

CONCLUSIONS

The results indicate that the use of the AVF.SIM system allowed to predict with a good accuracy the blood flow volume achievable after VA maturation, for a given location and type of anastomosis. This information may help in AVF surgical planning, reducing the AVFs with too low or too high blood flow, thus improving AVF patency rate and clinical outcome of renal replacement therapy.

Computer-assisted intraoperative 3D-navigation for liver surgery: a prospective randomized-controlled pilot study

Background

Liver surgery is the standard of care for primary and many secondary liver tumors. Due to variability and complexity in liver anatomy preoperative imaging is necessary to determine resectability and for planning the surgical strategy. In the last few years, computer-assisted resection planning has been introduced in liver surgery. Aim of this trial was the evaluation of computer-assisted three-dimensional (3D)-navigation for liver surgery.

Methods

This study was a prospective randomized-controlled pilot trial and patients were randomized in navigated or non-navigated group. Primary end point was the quotient of intraoperative resected volume and planned resection volume. Secondary end points included operation time, resection margin and postoperative complications. 3D reconstructions were performed with MeVis Distant Services (MeVis AG, Bremen, Germany). The navigation system CAS-One Liver (CAScination AG, Bern, Switzerland) was used for intraoperative computer-assisted 3D-navigation.

Results

The data of 16 patients with 20 liver tumors were used in this analysis. Of these, 8 liver tumors were resected with the utilization of intraoperative navigation. Two postoperative complications were classified grade IIIa or higher. There was no difference in duration of operation (189 vs. 180 min, P=0.970), rate of postoperative complications (n=1 vs. n=1, P=0.696) and length of hospital stay (9 vs. 7 days, P=0.368) between the two groups. Minimal resection margin (0.15 vs. 0.40 cm, P=0.384) and quotient of planned to intraoperative resection volume (0.94 vs. 1.11, P=0.305) were also similar.

Conclusions

Intraoperative navigation is a technology that can be safely used during liver resection. Surgical accuracy is not yet superior to the current standard of intraoperative orientation. Further technological advances with suitable deformation algorithms and augmented reality systems will enable a further improvement of the technical feasibility.

The Current Burden and Future Solutions for Preoperative Cataract-Refractive Evaluation Diagnostic Devices: A Modified Delphi Study

Purpose

To obtain consensus on the key areas of burden associated with existing devices and to understand the requirements for a comprehensive next-generation diagnostic device to be able to solve current challenges and provide more accurate prediction of intraocular lens (IOL) power and presbyopia correction IOL success.

Patients and Methods

Thirteen expert refractive cataract surgeons including three steering committee (SC) members constituted the voting panel. Three rounds of voting included a Round 1 structured electronic questionnaire, Round 2 virtual face-to-face meeting, and Round 3 electronic questionnaire to obtain consensus on topics related to current limitations and future solutions for preoperative cataract-refractive diagnostic devices.

Results

Forty statements reached consensus including current limitations (n = 17) and potential solutions (n = 23) associated with preoperative diagnostic devices. Consistent with existing evidence, the panel reported unmet needs in measurement accuracy and validation, IOL power prediction, workflow, training, and surgical planning. A device that facilitates more accurate corneal measurement, effective IOL power prediction formulas for atypical eyes, simplified staff training, and improved decision-making process for surgeons regarding IOL selection is expected to help alleviate current burdens.

Conclusion

Using a modified Delphi process, consensus was achieved on key unmet needs of existing preoperative diagnostic devices and requirements for a comprehensive next-generation device to provide better objective and subjective outcomes for surgeons, technicians, and patients.

Case report: Use of three-dimensional technology in criss-cross heart with double outlet right ventricle

Background

In this case report, we utilized a three-dimensional printing model to replicate the complex anatomy of a criss-cross heart with double outlet right ventricle-an extremely rare congenital cardiac abnormality. This approach facilitated our understanding of the patient's unique condition and enabled us to plan the surgical procedure with greater precision.

Case presentation

Our department received a 13-year-old female patient who presented with a pronounced heart murmur and a decrease in exercise capacity. Subsequent two-dimensional imaging revealed the presence of a criss-cross heart with double outlet right ventricle-an intricate and uncommon cardiac malformation that poses challenges for accurate visualization through conventional two-dimensional modalities. To address this challenge, we constructed and printed a three-dimensional model using computed tomography data, which enabled us to visualize and understand the complex intracardiac structures and plan surgical interventions with greater precision. Using this approach, we successfully performed a right ventricular double outlet repair, and the patient made a full recovery following the procedure.

Conclusion

The criss-cross heart with double outlet right ventricle constitutes a complex and uncommon cardiac anomaly that poses considerable challenges in terms of diagnosis and surgical intervention. Employing three-dimensional modeling and printing represents a promising approach, given its potential to enhance the precision and comprehensiveness of the anatomical evaluation of the heart. As a result, this method holds significant promise in facilitating accurate diagnosis, meticulous surgical planning, and ultimately improving clinical outcomes for patients affected by this condition.

Model-assisted marsupialization of a large odontogenic keratocyst in the maxillofacial region using a multicolored 3D-printed model: A novel approach in surgical planning and teaching

3D printing can improve surgical planning and coordination between the healthcare team and serve as a valuable educational tool for students.

Abstract

Although the occurrence of odontogenic keratocysts (OKCs) in the maxillofacial region is not uncommon, their aggressive growth behavior requires advanced surgical techniques for minimal recurrence. The current case report describes the use of a multicolored 3D-printed model as an interactive visual aid for the surgical planning and management of an OKC treated with a minimally invasive surgical decompression technique. A cone-beam computed tomography scan of the patient showed a profound OKC involving the left side of the body of the mandible. A 3D printer was used to print a multicolor resin model of the patient's OKC lesion within the mandible. The printed model was successfully used as a planning tool for surgical intervention (i.e., marsupialization and enucleation) of the OKC. The model was also used as a handheld interactive visual aid for dental students, so they could more effectively understand the anatomical and surgical complexity of the case. The novel use of the multicolor 3D-printed model for treatment of this OKC improved visualization of the lesion during surgical planning and was a valuable teaching tool for educational discussion of this case.

Analysis of pulmonary artery variation based on 3D reconstruction of CT angiography

Objective: The aim of this study is to acquire pulmonary CT (Computed tomography) angiographic data for the purpose of creating a three-dimensional reconstruction. Additionally, we aim to analyze the features and deviations of the branches in both pulmonary lobes. This information is intended to serve as a more comprehensive and detailed reference for medical professionals when conducting preoperative evaluations and devising surgical plans. Method: Between August 2019 and December 2021, 420 patients were selected from the thoracic surgery department at the First Hospital of Jilin University, and underwent pulmonary 64 channel contrast enhanced CT examinations (Philips ICT 256). The images were acquired at a 1.5 mm slice thickness, and the DCM files that complied with DICOM (Digital Imaging and Communications in Medicine) standards were analysed for 3D (three dimensional) reconstruction using Mimics 22.0 software. The reconstructed pulmonary artery models were assessed by attending chest surgeons and radiologists with over 10 years of clinical experience. The two-dimensional image planes, as well as the coronary and sagittal planes, were utilized to evaluate the arteries. The study analyzed the characteristics and variations of the branches and courses of pulmonary arteries in each lobe of the lungs, with the exception of the subsegmental arterial system. Two chest surgeons and two radiologists with professional titles-all of whom had over a decade of clinical experience-jointly evaluated the 3D models of the pulmonary artery and similarly assessed the characteristics and variations of the branches and courses in each lobe of the lungs. Results: Significant variations were observed in the left superior pulmonary artery across the 420 subjects studied. In the left upper lobe, the blood supply of 4 arteries accounted for 50.5% (n = 212), while the blood supply of 2 arteries in the left lower lobe was the most common, accounting for 79.5% (n = 334). The greatest variation in the right pulmonary artery was observed in the branch supply of the right upper lobe mediastinal artery. In the majority of cases (77.9%), there were two arteries present, which was the most common configuration observed accounting for 64% (n = 269). In the right inferior lobe of the lung, there were typically 2-4 arteries, with 2 arteries being the most common configuration (observed in 79% of cases, n = 332). Conclusion: The three-dimensional reconstruction of pulmonary artery CT angiography enables clear observation of the branches and distribution of the pulmonary artery while also highlighting any variations. This technique holds significant clinical value for preoperative assessments regarding lesions and blood vessels.

Virtual Reality and Augmented Reality in Plastic and Craniomaxillofacial Surgery: A Scoping Review

Virtual reality (VR) and augmented reality (AR) have evolved since their introduction to medicine in the 1990s. More powerful software, the miniaturization of hardware, and greater accessibility and affordability enabled novel applications of such virtual tools in surgical practice. This scoping review aims to conduct a comprehensive analysis of the literature by including all articles between 2018 and 2021 pertaining to VR and AR and their use by plastic and craniofacial surgeons in a clinician-as-user, patient-specific manner. From the initial 1637 articles, 10 were eligible for final review. These discussed a variety of clinical applications: perforator flaps reconstruction, mastectomy reconstruction, lymphovenous anastomosis, metopic craniosynostosis, dermal filler injection, auricular reconstruction, facial vascularized composite allotransplantation, and facial artery mapping. More than half (60%) involved VR/AR use intraoperatively with the remainder (40%) examining preoperative use. The hardware used predominantly comprised HoloLens (40%) and smartphones (40%). In total, 9/10 Studies utilized an AR platform. This review found consensus that VR/AR in plastic and craniomaxillofacial surgery has been used to enhance surgeons' knowledge of patient-specific anatomy and potentially facilitated decreased intraoperative time via preoperative planning. However, further outcome-focused research is required to better establish the usability of this technology in everyday practice.

Patient-Specific 3D Printed Soft Models for Liver Surgical Planning and Hands-On Training

Background: Pre-surgical simulation-based training with three-dimensional (3D) models has been intensively developed in complex surgeries in recent years. This is also the case in liver surgery, although with fewer reported examples. The simulation-based training with 3D models represents an alternative to current surgical simulation methods based on animal or ex vivo models or virtual reality (VR), showing reported advantages, which makes the development of realistic 3D-printed models an option. This work presents an innovative, low-cost approach for producing patient-specific 3D anatomical models for hands-on simulation and training. Methods: The article reports three paediatric cases presenting complex liver tumours that were transferred to a major paediatric referral centre for treatment: hepatoblastoma, hepatic hamartoma and biliary tract rhabdomyosarcoma. The complete process of the additively manufactured liver tumour simulators is described, and the different steps for the correct development of each case are explained: (1) medical image acquisition; (2) segmentation; (3) 3D printing; (4) quality control/validation; and (5) cost. A digital workflow for liver cancer surgical planning is proposed. Results: Three hepatic surgeries were planned, with 3D simulators built using 3D printing and silicone moulding techniques. The 3D physical models showed highly accurate replications of the actual condition. Additionally, they proved to be more cost-effective in comparison with other models. Conclusions: It is demonstrated that it is possible to manufacture accurate and cost-effective 3D-printed soft surgical planning simulators for treating liver cancer. The 3D models allowed for proper pre-surgical planning and simulation training in the three cases reported, making it a valuable aid for surgeons.

Use of Virtual Reality and Three-Dimensional Printing in the Surgical Planning of Slide Tracheoplasty

Purpose: To describe our experience using virtual reality (VR) and three-dimensional (3D) printing as complements for the surgical planning process of slide tracheoplasty (ST) in patients with congenital tracheal stenosis (CTS). Description: VR and 3D printing are used for the surgical planning of ST as a therapeutic option in three female patients under five years of age with CTS. Evaluation: We assessed the planned surgical procedure, procedural time, postoperative complications, and outcomes, as well as the main surgeon's experience with the use of the applied technologies. Conclusions: The interaction within the VR environment allowed for collaboration of the surgical plan between surgical staff and enhancement of the radiologist-surgeon communication, while procedural simulation with 3D printing prototypes allowed for refining technical abilities for the surgical interventions. Based on our experience, the application of these technologies have added value to the surgical planning of ST and its outcomes in the treatment of CTS.

Surgical planning of arteriovenous fistulae in routine clinical practice: A machine learning predictive tool

BACKGROUND

Arteriovenous fistula (AVF) is the preferred vascular access (VA) for hemodialysis, but it is associated with high non-maturation and failure rates. Predicting patient-specific AVF maturation and postoperative changes in blood flow volumes (BFVs) and vessel diameters is of fundamental importance to support the choice of optimal AVF location and improve VA survival. The goal of this study was to employ machine learning (ML) in order to give physicians a fast and easy-to-use tool that provides accurate patient-specific predictions, useful to make AVF surgical planning decisions.

METHODS

We applied a set of ML approaches on a dataset of 156 patients. Both parametric and non-parametric ML approaches, taking preoperative data as input, were exploited to predict maturation, postoperative BFVs, and diameters. The best approach associated with lowest cross-validation errors between predictions and real measurements was then chosen to provide estimates and quantify prediction errors.

RESULTS

The k-NN was the best approach to predict brachial BFV, AVF maturation, and other VA variables, and it was also associated with the least computational effort. With this approach, the confusion matrices proved the high accuracy of the prediction for AVF maturation (96.8%) and the low absolute error distribution for the continuous BFV and diameter variables.

CONCLUSIONS

Our data-based approach provided accurate patient-specific predictions for different AVF configurations, requiring short computational time as compared to a physical model we previously developed. By supporting VA surgical planning, this fast computing approach could allow AVF surgical planning and help reducing the rate of non-maturation, which might ultimately have a broad impact on the management of hemodialysis patients.

Personalized surgical planning for coronary bypass graft configurations using patient-specific computational modeling to avoid flow competition in arterial grafts

Objectives

Flow competition between coronary artery bypass grafts (CABG) and native coronary arteries is a significant problem affecting arterial graft patency. The objectives of this study were to compare the predictive hemodynamic flow resulting from various total arterial grafting configurations and to evaluate whether the use of computational fluid dynamics (CFD) models capable of predicting flow can assist surgeons to make better decisions for individual patients by avoiding poorly functioning grafts.

Methods

Sixteen cardiac surgeons declared their preferred CABG configuration using bilateral internal mammary and radial arteries for each of 5 patients who had differing degrees of severe triple vessel coronary disease. Surgeons selected both a preferred 'aortic' strategy, with at least one graft arising from the ascending aorta, and a preferred "anaortic" strategy which could be performed as a "no-aortic touch" operation. CT coronary angiograms of the 5 patients were coupled to CFD models using a novel flow solver "COMCAB." Twelve different CABG configurations were compared for each patient of which 4 were "aortic" and 8 were "anaortic." Surgeons then selected their preferred grafting configurations after being shown predictive hemodynamic metrics including functional assessment of stenoses (instantaneous wave-free ratio; fractional flow reserve), transit time flowmetry graft parameters (mean graft flow; pulsatility index) and myocardial perfusion.

Results

A total of 87.5% (7/8) of "anaortic" configurations compared to 25% (1/4) of "aortic" configurations led to unsatisfactory grafts in at least 1 of the 5 patients (P = 0.038). The use of the computational models led to a significant decrease in the selection of unsatisfactory grafting configurations when surgeons employed "anaortic" (21.25% (17/80) vs. 1.25% (1/80), P < 0.001) but not "aortic" techniques (5% (4/80) vs. 0% (0/80), P = 0.64). Similarly, there was an increase in the selection of ideal configurations for "anaortic" (6.25% (5/80) vs. 28.75% (23/80), P < 0.001) but not "aortic" techniques (65% (52/80) vs. 61.25% (49/80), P = 0.74). Furthermore, surgeons who planned to use more than one unique "anaortic" configuration across all 5 patients increased (12.5% (2/16) vs. 87.5% (14/16), P<0.001).

Conclusions

"COMCAB" is a promising tool to improve personalized surgical planning particularly for CABG configurations involving composite or sequential grafts which are used more frequently in anaortic operations.

The impact of fusion imaging technique on middle ear cholesteatoma surgery: a prospective comparative study

BACKGROUND

The fusion of computed tomography images with non-echo planner diffusion-weighted magnetic resonance images may overcome the limitations of each individual modality.

OBJECTIVES

This study aimed to assess the ability of the 'fusion' technique to predict the location of middle ear cholesteatoma by evaluating Its impact on preoperative surgical planning and postoperative results.

METHODOLOGY

Eighty-three adults with cholesteatoma underwent preoperative CT scans and non-EPI-DW-MRI with or without the 'fusion' technique. We evaluated cholesteatoma localization in both groups, selecting the most appropriate surgical technique, and correlating it with the intraoperative findings. Both groups were compared in terms of residual/recurrent cholesteatoma at one, six and twelve months after surgery.

RESULTS

The 'fusion' technique's sensitivity, specificity, and accuracy in predicting the location of cholesteatoma were 97.5. 97.4, and 97.5%, respectively, versus 97.59, 57.69, and 73.21% of CT alone. There was a total operators agreement after the evaluation of the 'fusion' images with the adopted surgical technique. A statistically significant decrease in residual and recurrence cholesteatoma rates was found in group A.

CONCLUSIONS

The 'fusion' technique provides the surgeon with the precise cholesteatoma location, guiding him in making the correct surgical decision, contributing to the decrease in postoperative residual and recurrence rates.

Lesion-to-anal-verge distance in rectosigmoid endometriosis on transvaginal sonography vs magnetic resonance imaging: prospective study

OBJECTIVES

To compare transvaginal sonography (TVS) and magnetic resonance imaging (MRI) with intraoperative measurement (IOM) using a rectal probe in the estimation of the location of rectosigmoid endometriotic lesions, i.e. lesion-to-anal-verge distance (LAVD), and to compare two different MRI techniques for measuring LAVD.

METHODS

This was a prospective single-center observational study that included women undergoing surgery for symptomatic rectosigmoid endometriosis by discoid (DR) or segmental (SR) resection from December 2018 to December 2019. TVS and MRI were performed presurgically for each participant to evaluate LAVD, and the measurements on imaging were compared with IOM using a rectal probe. Clinically acceptable difference and limits of agreement (LoA) between TVS and MRI compared with IOM were set at ± 20 mm. Two different measuring methods for MRI, MRI_Center and MRI_Direct , were proposed and evaluated, as there is currently no guideline to describe deep endometriosis on MRI. Bland-Altman plots and LoA were used to assess agreement of TVS and both MRI methods with IOM. Systematic and proportional biases were assessed using paired t-test and Bland-Altman plots.

RESULTS

Seventy-five women were eligible for inclusion. Twenty-eight women were excluded, leaving 47 women for the analysis. Twenty-three DR and 26 SR procedures were performed, with both procedures performed in two women. The Bland-Altman plots showed that there were no systematic differences between TVS or MRI_Center when compared with IOM for all included participants. MRI_Direct systematically underestimated LAVD for lesions located further from the anal verge. TVS, MRI_Center and MRI_Direct had LoA outside the preset clinically acceptable difference when compared with IOM. LAVD was within the clinically acceptable difference from IOM of ± 20 mm in 70% (33/47) of women on TVS, 72% (34/47) of women on MRI_Center and 47% (22/47) of women on MRI_Direct .

CONCLUSIONS

TVS should be the preferred method to estimate the location of a rectosigmoid endometriotic lesion, i.e. LAVD, as it is more available, less expensive and has a similar accuracy to that of MRI. Estimating LAVD can be relevant for planning colorectal surgery for rectosigmoid endometriosis. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Task-based functional magnetic resonance imaging prediction of postsurgical cognitive outcomes in temporal lobe epilepsy: A systematic review, meta-analysis, and new data

Task-based functional magnetic resonance imaging (tfMRI) has developed as a common alternative in epilepsy surgery to the intracarotid amobarbital procedure, also known as the Wada procedure. Prior studies have implicated tfMRI as a comparable predictor of postsurgical cognitive outcomes. However, the predictive validity of tfMRI has not been established. This preregistered systematic review and meta-analysis (CRD42020183563) synthesizes the literature predicting postsurgical cognitive outcomes in temporal lobe epilepsy (TLE) using tfMRI. The PubMed and PsycINFO literature databases were queried for English-language articles published between January 1, 2009 and December 31, 2020 associating tfMRI laterality indices or symmetry of task activation with outcomes in TLE. Their references were reviewed for additional relevant literature, and unpublished data from our center were incorporated. Nineteen studies were included in the meta-analysis. tfMRI studies predicted postsurgical cognitive outcomes in left TLE ( ρ ̂ = -.27, 95% confidence interval [CI] = -.32 to -.23) but not right TLE ( ρ ̂ = -.02, 95% CI = -.08 to .03). Among studies of left TLE, language tfMRI studies were more robustly predictive of postsurgical cognitive outcomes ( ρ ̂ = -.27, 95% CI = -.33 to -.20) than memory tfMRI studies ( ρ ̂ = -.27, 95% CI = -.43 to -.11). Further moderation by cognitive outcome domain indicated language tfMRI predicted confrontation naming ( ρ ̂ = -.32, 95% CI = -.41 to -.22) and verbal memory ( ρ ̂ = -.26, 95% CI = -.35 to -.17) outcomes, whereas memory tfMRI forecasted only verbal memory outcomes ( ρ ̂ = -.37, 95% CI = -.57 to -.18). Surgery type, birth sex, level of education, age at onset, disease duration, and hemispheric language dominance moderated study outcomes. Sensitivity analyses suggested the interval of postsurgical follow-up, and reporting and methodological practices influenced study outcomes as well. These findings intimate tfMRI is a modest predictor of outcomes in left TLE that should be considered in the context of a larger surgical workup.

Novel AI-Based Algorithm for the Automated Computation of Coronal Parameters in Adolescent Idiopathic Scoliosis Patients: A Validation Study on 100 Preoperative Full Spine X-Rays

STUDY DESIGN

Retrospective, mono-centric cohort research study.

OBJECTIVES

The purpose of this study is to validate a novel artificial intelligence (AI)-based algorithm against human-generated ground truth for radiographic parameters of adolescent idiopathic scoliosis (AIS).

METHODS

An AI-algorithm was developed that is capable of detecting anatomical structures of interest (clavicles, cervical, thoracic, lumbar spine and sacrum) and calculate essential radiographic parameters in AP spine X-rays fully automatically. The evaluated parameters included T1-tilt, clavicle angle (CA), coronal balance (CB), lumbar modifier, and Cobb angles in the proximal thoracic (C-PT), thoracic, and thoracolumbar regions. Measurements from 2 experienced physicians on 100 preoperative AP full spine X-rays of AIS patients were used as ground truth and to evaluate inter-rater and intra-rater reliability. The agreement between human raters and AI was compared by means of single measure Intra-class Correlation Coefficients (ICC; absolute agreement; >.75 rated as excellent), mean error and additional statistical metrics.

RESULTS

The comparison between human raters resulted in excellent ICC values for intra- (range: .97-1) and inter-rater (.85-.99) reliability. The algorithm was able to determine all parameters in 100% of images with excellent ICC values (.78-.98). Consistently with the human raters, ICC values were typically smallest for C-PT (eg, rater 1A vs AI: .78, mean error: 4.7°) and largest for CB (.96, -.5 mm) as well as CA (.98, .2°).

CONCLUSIONS

The AI-algorithm shows excellent reliability and agreement with human raters for coronal parameters in preoperative full spine images. The reliability and speed offered by the AI-algorithm could contribute to the efficient analysis of large datasets (eg, registry studies) and measurements in clinical practice.

Three-Dimensional-Enabled Surgical Planning for the Correction of Right Partial Anomalous Pulmonary Venous Return

Objectives: The surgical technique for right partial anomalous pulmonary venous return (PAPVR) depends on the location of the anomalous pulmonary veins (PVs). With this in mind, we sought to evaluate the impact of 3D heart segmentation and reconstruction on preoperative surgical planning. Methods: A retrospective study was conducted on all patients who underwent PAPVR repair at our institution between January 2018 and October 2021; three-dimensional segmentations and reconstructions of all the heart anatomies were performed. A score (the PAPVR score) was established and calculated using two anatomical parameters (the distance between the most cranial anomalous PV and the superior rim of the sinus venosus defect/the sum of the latter and the distance between the PV and the azygos vein) to predict the type of correction. Results: A total of 30 patients were included in the study. The PAPVR score was found to be a good predictor of the type of surgery performed. A value > 0.68 was significantly associated with a Warden procedure (p < 0.001) versus single/double patch repair. Conclusions: Three-dimensional heart segmentations and reconstructions improve the quality of surgical planning in the case of PAPVR and allow for the introduction of a score that may facilitate surgical decisions on the type of repair required.

Exploring Noncardiac Surgical Needs From Infancy to Adulthood in Patients With Congenital Heart Disease

OBJECTIVES

As life expectancy for patients born with congenital heart disease (CHD) continues to rise, these patients will present increasingly for noncardiac surgery during childhood and adolescence. This study aimed to map the lifespan of noncardiac surgical needs among patients with CHD and explore how these needs may change over time.

DESIGN

All patients with CHD presenting for noncardiac surgery between 2008 and 2014 were selected for review.

SETTING

The study was conducted at a single urban academic tertiary pediatric hospital.

PARTICIPANTS

All patients with CHD presenting for noncardiac surgery during the study period were included and grouped by cardiac diagnosis.

INTERVENTIONS

Descriptive analysis included patient demographics, CHD diagnosis, procedures performed, and clinical data, including baseline saturation and underlying cardiac function.

MEASUREMENTS AND MAIN RESULTS

A total of 3,011 noncardiac surgical procedures were performed on patients with CHD during the study period. The most common CHD diagnoses were patent ductus arteriosus (27.6%), ventricular septal defects (24.7%), and patent foramen ovale (24.3%). The median age was 4 years, 87% of all the patients were ≤10 years, and 41% had associated syndromes. Of the patients, 76% underwent a preoperative echocardiogram, and 10% had depressed cardiac function at the time of surgery. The most common procedures performed were ear, nose, and throat (20%), general surgery (14%), and radiology (11%). Intraoperative events were reported in 488 out of 3,010 encounters (16.2%), with the highest rates reported in patients with single-ventricle physiology (55/179; 30.7%).

CONCLUSIONS

These findings suggested a greater burden of noncardiac surgery in lower age groups, with ear, nose, and throat and general surgery most common in young children and orthopedic and dental procedures increasing in adolescence.

3D renal model for surgical planning of partial nephrectomy: A way to improve surgical outcomes

OBJECTIVE

to evaluate the impact of 3D model for a comprehensive assessment of surgical planning and quality of partial nephrectomy (PN).

MATERIALS AND METHODS

195 patients with cT1-T2 renal mass scheduled for PN were enrolled in two groups: Study Group (n= 100), including patients referred to PN with revision of both 2D computed tomography (CT) imaging and 3D model; Control group (n= 95), including patients referred to PN with revision of 2D CT imaging. Overall, 20 individuals were switched to radical nephrectomy (RN). The primary outcome was the impact of 3D models-based surgical planning on Trifecta achievement (defined as the contemporary absence of positive surgical margin, major complications and ≤30% postoperative eGFR reduction). The secondary outcome was the impact of 3D models on surgical planning of PN. Multivariate logistic regressions were used to identify predictors of selective clamping and Trifecta's achievement in patients treated with PN (n=175).

RESULTS

Overall, 73 (80.2%) patients in Study group and 53 (63.1%) patients in Control group achieved the Trifecta (p=0.01). The preoperative plan of arterial clamping was recorded as clampless, main artery and selective in 22 (24.2%), 22 (24.2%) and 47 (51.6%) cases in Study group vs. 31 (36.9%), 46 (54.8%) and 7 (8.3%) cases in Control group, respectively (p<0.001). At multivariate logistic regressions, the use of 3D model was found to be independent predictor of both selective or super-selective clamping and Trifecta's achievement.

CONCLUSION

3D-guided approach to PN increase the adoption of selective clamping and better predict the achievement of Trifecta.