Recent advances in 3D computed tomography techniques for simulation and navigation in hepatobiliary pancreatic surgery

An analysis of virtual reality in abdominal surgery-A scoping review

BACKGROUND

The integration of virtual reality (VR) in surgery has gained prominence as VR applications have increased in popularity.

METHODS

A scoping review was undertaken, gathering the most relevant sources, utilising a detailed literature search of medical and academic databases including EMBASE, PubMed, Cochrane, IEEE, Google Scholar, and the Google search engine.

RESULTS

Of the 18 articles included, 7 focused on VR in colon surgery, 5 addressed VR in pancreas surgery, and the remaining 6 concentrated on VR in liver surgery. All the articles concluded that VR has a promising future in abdominal surgery by facilitating precision, visualisation, and surgeon training.

CONCLUSIONS

Adopting VR technology in abdominal surgery has the potential to improve preoperative planning, decrease perioperative anxiety among patients, and facilitate the training of surgeons, residents, and medical students. Additional supporting studies are necessary before VR can be widely implemented in surgical care delivery.

Design and Simulate Intracranial Support to Guide Maxillo Surgery: A Study Based on Bioengineering

BACKGROUND

Intraoperative navigation allows for the creation of a real-time relationship between the anatomy imagined during diagnosis/planning and the site of surgical interest. This procedure takes place by identifying and registering trustworthy anatomical markers on planning images and using a point locator during the operation. The locator is calibrated in the workspace by placing a Dynamic Reference Frame (DRF) sensor.

OBJECTIVE

This study aims to calculate the localization accuracy of an electromagnetic locator of neuro-maxillofacial surgery, moving the standard sensor position to a different position more suitable for maxillofacial surgery.

MATERIALS AND METHODS

The upper dental arch was chosen as an alternative fixed point for the positioning of the sensor. The prototype of a bite support device was designed and generated via 3D printing. CT images of a skull phantom with 10 anatomical landmarks were acquired. The testing procedure consisted of 10 measurements for each position of the sensor: precisely 10 measurements with the sensor placed on the forehead and 10 measurements with the sensor placed on the bite support device. It also evaluated the localization error by comparing the two procedures.

RESULTS

The localization error, when the sensor was placed on the bite support device, was lower in the sphere located on the temporal bone. It was the same in the spheres located on the maxillary bone. The test analysis of the data of the new device showed that it is reliable; the tests are reproducible and can be considered as accurate as the traditional ones. In addition, the sensor mounted on this device has proven to be slightly superior in terms of accuracy and accuracy in areas such as the middle third of the face and jaw.

DISCUSSION AND CONCLUSION

The realization of the bite support device allowed the sensor to change position concerning its natural site. This procedure allows us to explore structures, such as the frontal site, which were initially difficult to approach with neuronavigation and improves the approach to midface structures, already studied with neuronavigation. The new calibration, with the position of the sensor on the support device in the same reference points sphere, highlighted the reduction in the location error. We can say that the support proposed in this study lays the foundations for a new navigation approach for patients in maxillofacial surgery, by changing the position of the sensor. It has strong points in improving the localization error for some reference points without determining disadvantages both in the calibration and in the surgical impediment.

Questionnaire survey of virtual reality experiences of digestive surgery at a rural academic institute: A pilot study for pre-surgical education

We developed a prototype VR platform, VECTORS L&M (VLM), aiming to enhance the understanding of digestive surgery for students, interns, and young surgeons by limiting costs. Its efficacy was assessed via questionnaires before implementation in surgical education. The VLM provides nine-minute VR views of surgeries, from both 180- and 360-degree angles. It was created with L.A.B. Co., Ltd. and incorporates surgery videos from biliary malignancy patients. Following VLM development, a survey was conducted among surgeons who had experienced it. Twenty-eight participants (32% of observers) responded to the survey. A majority (81%) reported positive experiences with the VR content and showed interest in VR video production, though some reported sickness. Most respondents were experienced surgeons, and nearly all believed VR was important for medical education with a mean score of 4.14 on a scale of up to 5. VR was preferred over 3D printed models due to its application versatility. Participants expressed the desire for future VR improvements, such as increased mobility, cloud connectivity, cost reduction, and better resolution. The VLM platform, coupled with this innovative teaching approach, offers experiential learning in intraabdominal surgery, effectively enriching the knowledge of students and surgeons ahead of surgical education and training.

The role of artificial intelligence in surgical simulation

Artificial Intelligence (AI) plays an integral role in enhancing the quality of surgical simulation, which is increasingly becoming a popular tool for enriching the training experience of a surgeon. This spans the spectrum from facilitating preoperative planning, to intraoperative visualisation and guidance, ultimately with the aim of improving patient safety. Although arguably still in its early stages of widespread clinical application, AI technology enables personal evaluation and provides personalised feedback in surgical training simulations. Several forms of surgical visualisation technologies currently in use for anatomical education and presurgical assessment rely on different AI algorithms. However, while it is promising to see clinical examples and technological reports attesting to the efficacy of AI-supported surgical simulators, barriers to wide-spread commercialisation of such devices and software remain complex and multifactorial. High implementation and production costs, scarcity of reports evidencing the superiority of such technology, and intrinsic technological limitations remain at the forefront. As AI technology is key to driving the future of surgical simulation, this paper will review the literature delineating its current state, challenges, and prospects. In addition, a consolidated list of FDA/CE approved AI-powered medical devices for surgical simulation is presented, in order to shed light on the existing gap between academic achievements and the universal commercialisation of AI-enabled simulators. We call for further clinical assessment of AI-supported surgical simulators to support novel regulatory body approved devices and usher surgery into a new era of surgical education.

Using virtual 3D-models in surgical planning: workflow of an immersive virtual reality application in liver surgery

Purpose

Three-dimensional (3D) surgical planning is widely accepted in liver surgery. Currently, the 3D reconstructions are usually presented as 3D PDF data on regular monitors. 3D-printed liver models are sometimes used for education and planning.

Methods

We developed an immersive virtual reality (VR) application that enables the presentation of preoperative 3D models. The 3D reconstructions are exported as STL files and easily imported into the application, which creates the virtual model automatically. The presentation is possible in “OpenVR”-ready VR headsets. To interact with the 3D liver model, VR controllers are used. Scaling is possible, as well as changing the opacity from invisible over transparent to fully opaque. In addition, the surgeon can draw potential resection lines on the surface of the liver. All these functions can be used in a single or multi-user mode.

Results

Five highly experienced HPB surgeons of our department evaluated the VR application after using it for the very first time and considered it helpful according to the “System Usability Scale” (SUS) with a score of 76.6%. Especially with the subitem “necessary learning effort,” it was shown that the application is easy to use.

Conclusion

We introduce an immersive, interactive presentation of medical volume data for preoperative 3D liver surgery planning. The application is easy to use and may have advantages over 3D PDF and 3D print in preoperative liver surgery planning. Prospective trials are needed to evaluate the optimal presentation mode of 3D liver models.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00423-021-02127-7.

Role of artificial intelligence in hepatobiliary and pancreatic surgery

Over the past decade, enhanced preoperative imaging and visualization, improved delineation of the complex anatomical structures of the liver and pancreas, and intra-operative technological advances have helped deliver the liver and pancreatic surgery with increased safety and better postoperative outcomes. Artificial intelligence (AI) has a major role to play in 3D visualization, virtual simulation, augmented reality that helps in the training of surgeons and the future delivery of conventional, laparoscopic, and robotic hepatobiliary and pancreatic (HPB) surgery; artificial neural networks and machine learning has the potential to revolutionize individualized patient care during the preoperative imaging, and postoperative surveillance. In this paper, we reviewed the existing evidence and outlined the potential for applying AI in the perioperative care of patients undergoing HPB surgery.

Split-bolus injection protocol with optimized timings of contrast medium injection and CT scanning for 3D CT angio-venography before laparoscopic gastrectomy

PURPOSE

To propose an optimization method of contrast medium injection for the split-bolus protocol based on the contrast medium pharmacokinetics and investigate the utility of the optimized split-bolus protocol in 3D CT angio-venography for laparoscopic gastrectomy.

MATERIALS AND METHODS

A pharmacokinetic relationship between injection duration and time to the peak enhancement was taken into account in the protocol design. The first 20 consecutive patients underwent a multi-phase scan with a single-bolus injection (single-bolus protocol), and the next 20 underwent the proposed split-bolus protocol. CT attenuations of the arteries and veins and dose-length products (DLPs) were compared between the two protocols. Two radiologists visually assessed arterial and venous depictions and the misregistrations.

RESULTS

Mean arterial CT attenuations were not significantly different between the two protocols. Though mean venous CT attenuations for the split-bolus protocol were 7-11% lower than those of the single-bolus protocol, they were visually evaluated as similar. The mean DLP of the split-bolus protocol was 46% lower than that of the single-bolus protocol. Misregistration between the arteries and veins occurred 35-80% during the single-bolus protocol, but was not indicated in the split-bolus protocol.

CONCLUSION

The split-bolus protocol with optimized timing was more effective for providing improved image quality with reduced radiation dose compared with the single-bolus protocol in 3D CT angio-venography for laparoscopic gastrectomy.

Efficacy of non-rigid registration technique for misregistration in 3D-CTA fusion imaging

PURPOSE

To assess whether fusion 3D-CTA images can be corrected using non-rigid registration (NRR) for gastroenterology imaging.

METHODS

This study included 55 patients before gastroenterology surgery who underwent preoperative 3D-CTA prior to gastroenterological surgery. We recorded the coordinate of measurement points on the arterial vessels (X, Y, and Z) in each portal phase, original image of the arterial phase, and arterial phase with NRR. The distance of misregistration between the two points was calculated with the coordinate of the original image with NRR and that of the portal phase as true value.

RESULTS

The distance of misregistration between the two points in the original arterial and portal phase images was significantly higher than that in the arterial phase image with NRR on all directions (p < 0.01).

CONCLUSIONS

This study showed that NRR may correct misregistration on fusion 3D-CTA imaging. Hence, it can visualize correctly the anatomy of the vessel.

Three-Dimensional Visualization Technology Used in Pancreatic Surgery: a Valuable Tool for Surgical Trainees

PURPOSE

Three-dimensional (3D) visualization technology has been increasingly applied in patient-specific surgeries, but its value in residency training has not been determined. This study aimed to explore the value of 3D visualized pancreatic model in tumor evaluation and surgery planning for surgical trainees.

METHODS

Eighty-eight surgical residents were randomized into two groups (computed tomography (CT) group and 3D group). Both groups began with a training on evaluating the resectability of pancreatic tumor, which was based on the NCCN clinical practice guidelines and practiced on a sample case. Then, they respectively learned the sample case either on 3D reconstruction visualization tables or CT images. Finally, both groups completed a same test consisting of two pancreatic cases with CT images as well as questionnaires.

RESULTS

No differences were found in scores of the anatomy and diagnosis part, while mean scores for questions, associated with tumor staging and surgery planning, were consistently and significantly higher in the 3D group. In addition, participants in 3D group agreed that 3D technology was more beneficial in understanding and making pancreatic surgery planning.

CONCLUSION

The 3D visualization table may be a potential supplemental learning tool in building anatomy-image-surgery knowledge system and thus making surgery planning for surgical trainees.

Digital and intelligent liver surgery in the new era: Prospects and dilemmas

Despite tremendous advances in traditional imaging technology over the past few decades, the intraoperative identification of lesions is still based on naked eye observation or pre-operative image evaluation. However, these two-dimensional image data cannot objectively reflect the complex anatomical structure of the liver and the detailed morphological features of the lesion, which directly limits the clinical application value of these imaging data in surgery in that it cannot improve the curative efficacy of surgery and the prognosis of the patient. This traditional mode of diagnosis and treatment has been changed by digital medical imaging technology in the new era with its significant function of accurate and efficient diagnosis of diseases, selection of reasonable treatment schemes, improvement of radical resection rate and reduction of surgical risk. In this paper, we reviewed the latest application of digital intelligent diagnosis and treatment technology related to liver surgery in the hope that it may help to achieve accurate treatment of liver surgery diseases.

Tracheobronchial angles in children: Three-dimensional computed tomography-based measurements

BACKGROUND

Studies have shown significant variation in the tracheobronchial angles in pediatric-aged patients. The current study revisits tracheobronchial angle measurements in children using accurate computed tomography-based 3-dimensional images to add clarity to the understanding of tracheobronchial angles. The primary objective of the current study was to measure the right and left bronchial angle take off from the trachea using 3-dimensional computed tomography-based images of the air column in the tracheobronchial tree.

METHODS

Computed tomography-based images of 45 children younger than 8 years were reviewed. The children were evaluated during spontaneous ventilation either during natural sleep or with sedation. The right and left bronchial angles were computed between the central axes of the respective main bronchi and a vertical line passing through the central axis of the longitudinal tracheal air column. The right and left bronchial angles were compared using paired t tests, and the age dependence of the right bronchial angle and left bronchial angle difference was evaluated using Pearson's correlation coefficient.

RESULTS

The study cohort included 18 males and 27 females with an average age of 49 ± 25 months. The right bronchial angle ranged from 23° to 56° (mean 42 ± 7°), whereas left bronchial angle varied between 25° and 68° (mean 43 ± 9°). The difference in means of 1 degree was not statistically significant (95% confidence interval of difference: -1°, 4°; P = .282). No association was found between left and right bronchial angle difference and patient age (r = -.019).

CONCLUSION

According to computed tomography-based 3-dimensional imaging, right and left bronchial angles are virtually identical in children up to 8 years of age, and the difference between right and left bronchial angles does not vary with age in this population.

Fast elastic registration of soft tissues under large deformations

A fast and accurate fusion of intra-operative images with a pre-operative data is a key component of computer-aided interventions which aim at improving the outcomes of the intervention while reducing the patient's discomfort. In this paper, we focus on the problematic of the intra-operative navigation during abdominal surgery, which requires an accurate registration of tissues undergoing large deformations. Such a scenario occurs in the case of partial hepatectomy: to facilitate the access to the pathology, e.g. a tumor located in the posterior part of the right lobe, the surgery is performed on a patient in lateral position. Due to the change in patient's position, the resection plan based on the pre-operative CT scan acquired in the supine position must be updated to account for the deformations. We suppose that an imaging modality, such as the cone-beam CT, provides the information about the intra-operative shape of an organ, however, due to the reduced radiation dose and contrast, the actual locations of the internal structures necessary to update the planning are not available. To this end, we propose a method allowing for fast registration of the pre-operative data represented by a detailed 3D model of the liver and its internal structure and the actual configuration given by the organ surface extracted from the intra-operative image. The algorithm behind the method combines the iterative closest point technique with a biomechanical model based on a co-rotational formulation of linear elasticity which accounts for large deformations of the tissue. The performance, robustness and accuracy of the method is quantitatively assessed on a control semi-synthetic dataset with known ground truth and a real dataset composed of nine pairs of abdominal CT scans acquired in supine and flank positions. It is shown that the proposed surface-matching method is capable of reducing the target registration error evaluated of the internal structures of the organ from more than 40 mm to less then 10 mm. Moreover, the control data is used to demonstrate the compatibility of the method with intra-operative clinical scenario, while the real datasets are utilized to study the impact of parametrization on the accuracy of the method. The method is also compared to a state-of-the art intensity-based registration technique in terms of accuracy and performance.

Impact of Three-Dimensional Surgical Simulation on Pancreatic Surgery

Background/Aims

Anatomical variations are frequently encountered during hepato-biliary-pancreatic surgeries, requiring surgeons to have a precise understanding of the surgical anatomy in order to perform a safe surgery. We evaluated the impact of novel three-dimensional (3D) surgical simulation on pancreatic surgeries to enhance surgical residents' understanding.

Methodology

Between January 2013 and May 2014, 61 preoperative 3D surgical simulations were performed. The consistency (0-10, with 10 representing 100% consistency) among the 15 surgical residents' anatomical drawings from multidetector computed tomography images and the simulated 3D images by SYNAPSE VINCENT® was assessed. We divided the surgical residents into two groups - first- to fifth-year postgraduate doctors (group A) and sixth- to tenth-year postgraduate doctors (group B) - and compared the self-assessment scores between these two groups.

Results

In terms of the self-assessment scores, a statistically significant difference was observed between the two groups (p < 0.001).

Conclusions

In this study, 3D surgical simulation was useful for preoperative assessments prior to pancreatic surgery, especially in younger postgraduate surgeons.

Pediatric upper airway dimensions using three-dimensional computed tomography imaging

INTRODUCTION

Computed tomography- (CT) and magnetic resonance imaging (MRI)-based measurements have recently suggested that the narrowest dimension of the pediatric airway is the subglottic region. These data are contrary to the previously held tenets of a funnel- or conical-shaped airway. The current study evaluates airway volumes and shapes using three-dimensional CT images of the air way column in spontaneously breathing children.

METHODS

The study included CT-based radiological images of the neck in children who required imaging unrelated to airway symptomatology. The children were evaluated during spontaneous ventilation during natural sleep or with sedation without airway devices in place. The three-dimensional images of the airway column were evaluated, volumes calculated, and comparisons made between the subglottic, cricoid, and tracheal volumes and shapes.

RESULTS

The study cohort included 54 children, ranging in age from 2 months to 8 years. An increase in the airway volumes was observed from the subglottic (0.17 ± 0.06 mm³ ) to the cricoid (0.19 ± 0.06 mm³ ) to the tracheal regions (0.22 ± 0.07 mm³ ). The volumes of the subglottic, cricoid, and tracheal regions demonstrated a linear relationship with age.

CONCLUSION

This study confirms recent studies demonstrating that the subglottic region not the cricoid is the narrowest part of the airway.

Three-dimensional simulation of pancreatic surgery showing the size and location of the main pancreatic duct

PURPOSE

We performed three-dimensional (3D) surgical simulation of pancreatic surgery, including the size and location of the main pancreatic duct on the resected pancreatic surface.

METHODS

The subjects of this retrospective analysis were 162 patients who underwent pancreatic surgery. This cohort was sequentially divided into a "without-3D" group (n = 81) and a "with-3D" group (n = 81). We compared the pancreatic duct diameter and its location, using nine sections in a grid pattern, with the intraoperative findings. The perioperative outcomes were also compared between patients who underwent pancreaticoduodenectomy (PD) and those who underwent distal pancreatectomy (DP).

RESULTS

There were no significant differences in the main pancreatic duct diameter between the 3D-simulated values and the operative findings. The 3D-simulated main pancreatic duct location was consistent with its actual location in 80 % of patients (65/81). In comparing the PD and DP groups, the intraoperative blood loss was 1174 ± 867 and 817 ± 925 ml in the without-3D group, and 828 ± 739 and 307 ± 192 ml in the with-3D group, respectively (p = 0.024, 0.026).

CONCLUSION

The 3D surgical simulation provided useful information to promote our understanding of the pancreatic anatomy, including details on the size and location of the main pancreatic duct.

Binocular stereo-navigation for three-dimensional thoracoscopic lung resection

Background

This study investigated the efficacy of binocular stereo-navigation during three-dimensional (3-D) thoracoscopic sublobar resection (TSLR).

Methods

From July 2001, the authors’ department began to use a virtual 3-D pulmonary model on a personal computer (PC) for preoperative simulation before thoracoscopic lung resection and for intraoperative navigation during operation. From 120 of 1-mm thin-sliced high-resolution computed tomography (HRCT)-scan images of tumor and hilum, homemade software CTTRY allowed sugeons to mark pulmonary arteries, veins, bronchi, and tumor on the HRCT images manually. The location and thickness of pulmonary vessels and bronchi were rendered as diverse size cylinders. With the resulting numerical data, a 3-D image was reconstructed by Metasequoia shareware. Subsequently, the data of reconstructed 3-D images were converted to Autodesk data, which appeared on a stereoscopic-vision display. Surgeons wearing 3-D polarized glasses performed 3-D TSLR.

Results

The patients consisted of 5 men and 5 women, ranging in age from 65 to 84 years. The clinical diagnoses were a primary lung cancer in 6 cases and a solitary metastatic lung tumor in 4 cases. Eight single segmentectomies, one bi-segmentectomy, and one bi-subsegmentectomy were performed. Hilar lymphadenectomy with mediastinal lymph node sampling has been performed in 6 primary lung cancers, but four patients with metastatic lung tumors were performed without lymphadenectomy. The operation time and estimated blood loss ranged from 125 to 333 min and from 5 to 187 g, respectively. There were no intraoperative complications and no conversion to open thoracotomy and lobectomy. Postoperative courses of eight patients were uneventful, and another two patients had a prolonged lung air leak. The drainage duration and hospital stay ranged from 2 to 13 days and from 8 to 19 days, respectively. The tumor histology of primary lung cancer showed 5 adenocarcinoma and 1 squamous cell carcinoma. All primary lung cancers were at stage IA. The organs having metastatic pulmonary tumors were kidney, bladder, breast, and rectum. No patients had macroscopically positive surgical margins.

Conclusions

Binocular stereo-navigation was able to identify the bronchovascular structures accurately and suitable to perform TSLR with a sufficient margin for small pulmonary tumors.

An update on laparoscopic liver resection: The French Hepato-Bilio-Pancreatic Surgery Association statement

Laparoscopic liver resection has been recognized as a safe and efficient approach since the Louisville Conference in 2008, but its use still remains confined to experienced teams in specialized centers, and may lack some standardization. The 2013 Session of French Association for Hepatobiliary and Pancreatic Surgery (ACHBT) specifically focused on laparoscopic liver surgery and the particular aspects and issues arising since the 2008 conference. Our objective is to provide an update and summarize the current French position on laparoscopic liver surgery. An overview of the current practice of laparoscopic liver resections in France since 2008 is presented. The issues surrounding standardization for left lateral sectionectomy and right hepatectomy, hybrid and hand-assisted techniques are raised and discussed. Finally, future technologies and technical perspectives are outlined.