3D Navigation Research Articles

Automatic Generation of 3D Indoor Navigation Networks from Building Information Modeling Data Using Image Thinning

Navigation networks are a common form of indoor map that provide the basis for a wide range of indoor location-based services, intelligent tasks for indoor robots, and three-dimensional (3D) geographic information systems. The majority of current indoor navigation networks are manually modeled, resulting in a laborious and fallible process. Building Information Modeling (BIM) captures design information, allowing for the automated generation of indoor maps. Most existing BIM-based navigation systems for floor-level wayfinding rely on well-defined spatial semantics, and do not adapt well to buildings with irregular 3D shapes, which can make cross-floor path generation difficult. This research introduces an innovative approach to generating 3D indoor navigation networks automatically from BIM data using image thinning, which is referred to as GINIT. Firstly, GINIT extracts grid-based maps for floors from BIM data using only two types of semantics, i.e., slabs and doors. Secondly, GINIT captures cross-floor paths from building components by projecting 3D forms onto a 2D image, thinning the 2D image to capture the 2D projection path, and crossing over the 2D routes with 3D routes to restore the 3D path. Finally, to demonstrate the effectiveness of GINIT, experiments were conducted on three real-world multi-floor buildings, evaluating its performance across eight types of cross-layer architectural component. GINIT overcomes the dependency of space definitions in current BIM-based navigation network generation schemes by introducing image thinning. Due to the adaptability of navigation image thinning to any binary image, GINIT is capable of generating navigation networks from building components with diverse 3D shapes. Moreover, the current studies on indoor navigation network extraction mainly use geometry theory, while this study is the first to generate 3D indoor navigation networks automatically using image thinning theory. The results of this study will offer a unique perspective and foster the exploration of imaging theory applications of BIM.

Comparison of accuracy for hip-knee-ankle (HKA) angle by X-ray and knee motion analysis system and the relationships between HKA and gait posture

BackgroundThe lower limb mechanical axis was used to assess the severity of knee osteoarthritis (KOA) with varus/valgus deformity and the accuracy of targeted lower limb alignment correction after operation by conventional X-rays. There are lots of parameters to assess the gait in elder patients such as velocity, stride length, step width and swing/stance ratio by knee joint movement analysis system. However, the correlation between the lower limb mechanical axis and gait parameters is not clear. This study is aimed at obtaining the accuracy of the lower limb mechanical axis by the knee joint movement analysis system and the correlation between the lower limb mechanical axis and gait parameters.MethodsWe analysed 3D knee kinematics during ground gait of 99 patients with KOA and 80 patients 6 months after the operations with the vivo infrared navigation 3D portable knee joint movement analysis system (Opti-Knee®, Innomotion Inc, Shanghai, China). The HKA (Hip-Knee-Ankle) value was calculated and compared to X-ray findings.ResultsHKA absolute variation after the operation was 0.83 ± 3.76°, which is lower than that before the operation (5.41 ± 6.20°, p = 0.001) and also lower than the entire cohort (3.36 ± 5.72). Throughout the cohort, a significant correlation with low coefficients (r = -0.19, p = 0.01) between HKA value and anterior-posterior displacement was found. In comparing the HKA values measured on the full-length alignment radiographs and 3D knee joint movement analysis system (Opti-Knee), there was a significant correlation with moderate to high coefficients (r = 0.784 to 0.976). The linear correlation analysis showed that there was a significant correlation between the values of HKA measured by X-ray and movement analysis system (R2 = 0.90, p < 0.01).ConclusionsData with equivalent results as HKA, the 6DOF of the knee and ground gait data could be provided by infrared navigation based 3D portable knee joint movement analysis system comparing with the conventional X-rays. There is no significant effect of HKA on the kinematics of the partial knee joint.

Segmentectomy versus lobectomy for deep clinical T1a-bN0M0 non-small cell lung cancer

ObjectivesWhether segmentectomy could yield similar oncological outcomes with lobectomy for cT1a-bN0M0 non-small cell lung cancer (NSCLC) in the deep lung parenchyma remained unclear. This study aimed to compare the long-term prognosis of segmentectomy and lobectomy for deep NSCLC. Materials and methodsWe retrospectively screened cT1a-bN0M0 NSCLC patients who underwent segmentectomy or lobectomy between 2012 and 2019. The 3D multiplanar reconstruction software was used to determine the tumor location. Log-rank test, Cox hazard proportional regression, and propensity score matching analyses were adopted for prognostic evaluation. ResultsIn total, 321 patients with segmentectomy and 239 subjects undergoing lobectomy with a median follow-up time of 48.2 months remained. All the patients had a R0 resection, and no 30-day or 90-day mortality was observed. The 5-year overall survival and disease-free survival were 99.0% and 96.6% for patients undergoing segmentectomy. No significant survival differences existed between segmentectomy and lobectomy after adjusting other factors (disease-free survival, DFS: HR = 1.20, 95%CI: 0.49–2.99, P = 0.688; overall survival, OS: HR = 1.09, 95%CI: 0.30–3.95, P = 0.892). After propensity score matching, patients with segmentectomy (n = 128) had a similar OS (P = 0.870) and DFS (P = 0.900) with those receiving lobectomy (n = 128). To further evaluate the outcomes of segmentectomy for deep lung cancer, 557 peripheral lung cancer patients who underwent segmentectomy at the same period were taken as the reference. As expected, segmentectomy for deep lesions achieved equivalent OS (P = 0.610) and DFS (P = 0.580) with the peripheral lesions. ConclusionsSegmentectomy could achieve comparable long-term outcomes with lobectomy for deep cT1a-bN0M0 NSCLC with careful preoperative design and 3D navigation.

Significant Reduction of Radiation Exposure Using Specific Settings of the O-Arm for Percutaneous Cementoplasty in Accordance With the ALARA Principle.

Three-dimensional (3D) navigation has become routinely used in spine surgery, allowing more accurate and safe procedures. However, radiation exposure related to the use of imaging is an unresolved issue, and information about it is relatively scarce. The "as low as reasonably achievable" (ALARA) principle aims to reduce the radiation exposure for the patients as low as possible. The objective of this study was to compare the effective dose related to the use of the O-arm in standard settings with adapted features for dose reduction during percutaneous cementoplasty. From March 2021 to October 2022, all consecutive patients who underwent navigated percutaneous cementoplasty with the use of the O-arm were prospectively included. Demographic, operative, irradiation, and radiological data were collected. The main outcome was the effective dose (E) in millisievert (mSv). Secondary outcomes were the absolute risk of cancer (AR) in percent equivalent to a whole-body exposition, operative time, and radiological results according to Garnier. In group A, patients were operated on with standard settings of the O-arm, whereas in group B, navigation on the field of view, collimation, and low-dose settings were used. A total of 70 patients were included in the study: 43 in group A and 27 in group B. Also, 109 vertebrae were operated: 59 in group A and 50 in group B. Mean E was significantly higher in group A than in group B (9.94 and 4.34 mSv, respectively; P < 0.01). The 3D-related E followed the same trend (7.82 and 3.97 mSv, respectively), as did 2-dimensional-related E (2.12 and 0.37 mSv, respectively; P < 0.01). Average AR was also significantly higher in group A than in group B (5.10-4% and 2.10-4% respectively; P < 0.01). Operative time was similar in both groups, but the rate of satisfactory radiological results was higher in group A than in group B (95% and 84%, respectively; P = 0.11), and we found similar rates of cement leakage (22% and 24%, respectively; P = 0.71). The application of settings of the O-arm in accordance with the ALARA principle helped to significantly reduce the radiation exposure and should be routinely used for O-arm-assisted cementoplasty procedures. This study details technical aspects and settings that may help users of the O-arm to decrease radiation exposure to patients and surgeons alike, especially in cementoplasty procedures, as well as in other procedures performed under O-arm guidance.

Water Skating Miniature Robot Propelled by Acoustic Bubbles.

This paper presents a miniature robot designed for monitoring its surroundings and exploring small and complex environments by skating on the surface of water. The robot is mainly made of extruded polystyrene insulation (XPS) and Teflon tubes and is propelled by acoustic bubble-induced microstreaming flows generated by gaseous bubbles trapped in the Teflon tubes. The robot's linear motion, velocity, and rotational motion are tested and measured at different frequencies and voltages. The results show that the propulsion velocity is proportional to the applied voltage but highly depends on the applied frequency. The maximum velocity occurs between the resonant frequencies for two bubbles trapped in Teflon tubes of different lengths. The robot's maneuvering capability is demonstrated by selective bubble excitation based on the concept of different resonant frequencies for bubbles of different volumes. The proposed water skating robot can perform linear propulsion, rotation, and 2D navigation on the water surface, making it suitable for exploring small and complex water environments.

Dopamine differentially modulates medial temporal lobe activity and behavior during spatial navigation in young and older adults

Aging is associated with changes in spatial navigation behavior. In addition to an overall performance decline, older adults tend to rely more on proximal location cue information than on environmental boundary information during spatial navigation compared to young adults. The fact that older adults are more susceptible to errors during spatial navigation might be partly attributed to deficient dopaminergic modulation of hippocampal and striatal functioning. Hence, elevating dopamine levels might differentially modulate spatial navigation and memory performance in young and older adults. In this work, we administered levodopa (L-DOPA) in a double-blind within-subject, placebo-controlled design and recorded functional neuroimaging while young and older adults performed a 3D spatial navigation task in which boundary geometry or the position of a location cue were systematically manipulated. An age by intervention interaction on the neural level revealed an upregulation of brain responses in older adults and a downregulation of responses in young adults within the medial temporal lobe (including hippocampus and parahippocampus) and brainstem, during memory retrieval. Behaviorally, L-DOPA had no effect on older adults’ overall memory performance; however, older adults whose spatial memory improved under L-DOPA also showed a shift towards more boundary processing under L-DOPA. In young adults, L-DOPA induced a decline in spatial memory performance in task-naïve participants. These results are consistent with the inverted-U-shaped hypothesis of dopamine signaling and cognitive function and suggest that increasing dopamine availability improves hippocampus-dependent place learning in some older adults.

Autostereoscopic 3D Augmented Reality Navigation for Laparoscopic Surgery: A Preliminary Assessment.

Since Augmented Reality (AR) and 3D visualization have proven to be of great significance to the safety and effectiveness of surgical outcomes, will autostereoscopic 3D AR without glasses bring new opportunities for surgical navigation of laparoscopic surgery? We used the CPD-based deformation registration algorithm and the proposed virtual view generation algorithm, realizing a deformable autostereoscopic 3D AR navigation framework for laparoscopic surgery. The depth perception and user experience of the 3D AR navigation were evaluated compared with the 2D AR display using an in-vitro porcine heart and offline clinical partial nephrectomy laparoscopic images. The autostereoscopic 3D AR allowed participants to have a more consistent spatial perception as well as a shorter measuring time than 2D AR with significant difference of p < 0.05. It can also improve relative depth perception for smaller distance separation of objects < = 3.28 mm. However, the autostereoscopic 3D AR perceived a worse experience compared to 2D AR in the user experience. Autostereoscopic 3D AR shows a more efficient and robust sense of spatial scale than 2D AR with better potential to shorten the operating time and improve surgical outcomes than 2D AR, but image blur and distortion are issues that must be solved to improve the perception effect. High precise registration and high fluency visualization requirements could make autostereoscopic 3D AR navigation for soft tissue more challenging. Our work lays a theoretical foundation for the further development of laparoscopic surgical navigation.

Эффективность трехмерной системы визуализации при выполнении лапароскопической радикальной простатэктомии.

Introduction. The three-dimensional (3D) imaging during laparoscopic procedures can improve the quality of that surgeries. There is a shortage of publications about the potential benefits of 3D navigation in laparoscopic surgery with urological diseases. Radical prostatectomy (RPE) is known as the gold standard of treatment of localized prostate cancer (PC), and investigation of imaging technologies in laparoscopic surgery in PC patients is a hot topic. Aim. To compare the perioperative outcomes of laparoscopic RPE performed with 3D and two-dimensional (2D) imaging. Materials and methods. We performed retrospective analysis of perioperative outcomes in 146 patients who had undergone radical surgery with localized PC. All the patients were divided into 4 groups by the surgery features: 1) 2D imaging with the technique for neurovascular bundles preservation (TNVBP) (n=52); 2) 2D without TNVBP (n=46); 3) 3D with TNVBP (n=23); 4) 3D without TNVBP (n=25). We assessed operative time, intraoperative blood loss volume (IBLV), duration of the bladder drainage, positive surgical margin (PSM) detection rate, duration of the postoperative inpatient period, urinary continence recovery rate, erectile function recovery (EFR) rate. Results and discussion. In groups 1, 2, 3, 4 the operative time was 171,4±21,1, 168,3±23,2, 98,7±17,3, 92,2±22,2 min, and the IBLV was 294,2±62,1, 281,2±53,2, 144,2±31,7, 148,5±33,0 mL, respectively. PSM detection rate was 1,92±0,11%, 2,17±0,04% in groups 1, 2, while PSM had not been detected in groups 3, 4. In all the participants, duration of the bladder drainage was 5–7 days, and the full recovery of urinary continence was detected at both 6 and 12 months after the surgery. The postoperative inpatient period was 8–10 days in groups 1, 2, and 8–9 days in groups 3, 4. The EFR at 3 months after the surgery was detected in 38,4%, 28,3%, 34.8%, 28.0% of patients, while at 12 months it was detected in 59,6%, 41,3%, 82,6%, 56,0% of patients in groups 1, 2, 3, 4, respectively. Conclusion. We revealed the following features of perioperative period of laparoscopic RPE performed with 3D imaging compared to 2D: 1) the operative time was reduced by 42–45% (р&lt;0,05); 2) the IBLV was reduced by 47–51% (р&lt;0,05); 3) the PSM had not been detected; 4) there was the tendency to the shorter postoperative inpatient period; 5) the EFR rate was increased by 1,3–1,4 times (р&lt;0,05), and the best EFR outcomes were obtained via 3D imaging together with TNVBP. Thus, our study demonstrates the advisability of usage of both 3D imaging and TNVBP during the laparoscopic RPE.

Scalable 3D mapping of cities using computer vision and signals of opportunity

Three-dimensional (3D) maps are used extensively in a variety of applications, from air and noise pollution modelling to location-based services such as 3D mapping-aided Global Navigation Satellite Systems (GNSS), and positioning and navigation for emergency service personnel, unmanned aerial vehicles and autonomous vehicles. However, the financial cost associated with creating and updating 3D maps using the current state-of-the-art methods such as laser scanning and aerial photogrammetry are prohibitively expensive. To overcome this, researchers have proposed using GNSS signals to create 3D maps. This paper advances that family of methods by proposing and implementing a novel technique that avoids the difficult step of directly classifying GNSS signals into line-of-sight and non-line-of-sight classes by utilising edge detection techniques adapted from computer vision. This prevents classification biases and increases the range of environments in which GNSS-based 3D mapping methods can be accurately deployed. Being based on the patterns of blockage and attenuation of GNSS signals that are freely and globally available to receive by many mobile phones, makes the proposed technique a free, scalable and accessible solution. This paper also identifies some key indicators affecting data collection scalability and efficiency of the 3D mapping solution.

A geometry-aware deep network for depth estimation in monocular endoscopy

Monocular depth estimation is critical for endoscopists to perform spatial perception and 3D navigation of surgical sites. However, most of the existing methods ignore the important geometric structural consistency, which inevitably leads to performance degradation and distortion of 3D reconstruction. To address this issue, we introduce a gradient loss to penalize edge fluctuations ambiguous around stepped edge structures and a normal loss to explicitly express the sensitivity to frequently small structures, and propose a geometric consistency loss to spreads the spatial information across the sample grids to constrain the global geometric anatomy structures. In addition, we develop a synthetic RGB-Depth dataset that captures the anatomical structures under reflections and illumination variations. The proposed method is extensively validated across different datasets and clinical images and achieves mean RMSE values of 0.066 (stomach), 0.029 (small intestine), and 0.139 (colon) on the EndoSLAM dataset. The generalizability of the proposed method achieves mean RMSE values of 12.604 (T1-L1), 9.930 (T2-L2), and 13.893 (T3-L3) on the ColonDepth dataset. The experimental results show that our method exceeds previous state-of-the-art competitors and generates more consistent depth maps and reasonable anatomical structures. The quality of intraoperative 3D structure perception from endoscopic videos of the proposed method meets the accuracy requirements of video-CT registration algorithms for endoscopic navigation. The dataset and the source code will be available at https://github.com/YYM-SIA/LINGMI-MR.

Application of 3D printing navigation system in pediatric epiphyseal complex lesion surgery

To investigate 3D printing navigation system in pediatric epiphyseal complex lesion surgery. 10 children with epiphyseal complex lesions of the lower limb were recruited. After collecting imaging data such as CT and MRI in children with epiphyseal complex lesions of the lower limb, a three-dimensional model of bone was constructed using 3D printed computer modeling technologies for the localization of the lesion area. The extent of bone bridges was less than 30%, and all of them met the indications for bone bridge resection surgery. 3D printed navigation templates guided lesion resection. Epiphyseal block growth regulation with a figure-of-eight plate was also used in cases with preexisting abnormal alignment. During the operation, the average surgical incision was 4.0 cm, the bone bridge positioning was accurate, and the bone bridge tissue could be successfully and completely removed. As a result of follow-up, no cases had residual bone bridge tissue, no iatrogenic epiphyseal injury was found, and the epiphyseal plate was open in all children. 3D printing navigation system improved the accuracy of resection of lower limb epiphyseal complex lesions, significantly reduced the need for intraoperative fluoroscopy, avoided iatrogenic injury to the epiphyseal complex due to positioning errors, thereby reducing postoperative complications and considerably improving the prognosis of a series of lower limb epiphyseal complex lesion diseases in children.

Model Predictive Control-Based 3D Navigation of a RIS-Equipped UAV for LoS Wireless Communication With a Ground Intelligent Vehicle

Model Predictive Control-Based 3D Navigation of a RIS-Equipped UAV for LoS Wireless Communication With a Ground Intelligent Vehicle

Hypertensive intracerebral hemorrhage: Which one should we choose between laser navigation and 3D navigation mold?

Hypertensive intracerebral hemorrhage (HICH) is a severe life-threatening disease, and its incidence has gradually increased in recent years. Due to the particularity and diversity of its bleeding sites, the early treatment of hematoma needs to be more meticulous and accurate, and minimally invasive surgery is often one of the measures that are commonly adopted now. The lower hematoma debridement and the navigation template created by 3D printing technology were compared in the external drainage of a hypertensive cerebral hemorrhage. Then the effect and feasibility of the two operations were explicitly evaluated. We performed a retrospective analysis of all eligible patients with HICH who underwent laser-guided hematoma evacuation or hematoma puncture under 3D-navigated molds at the Affiliated Hospital of Binzhou Medical University from January 2019 to January 2021. A total of 43 patients were treated. Twenty-three patients were treated with laser navigation-guided hematoma evacuation (group A); 20 patients were treated with 3D navigation minimally invasive surgery (group B). A comparative study was conducted between the two groups to evaluate the preoperative and postoperative conditions. The preoperative preparation time of the laser navigation group was significantly shorter than that of the 3D printing group. The operation time of the 3D printing group was better than that of the laser navigation group (0.73 ± 0.26 h vs. 1.03 ± 0.27 h P = 0.00070). In the improvement in the short-term postoperatively, there was no statistically significant difference between the laser navigation group and the 3D printing group (Median hematoma evacuation rate P = 0.14); And in the three-month follow-up NIHESS score, there was no significant difference between the two (P = 0.82). Laser-guided hematoma removal is more suitable for emergency operations, with real-time navigation and shortened preoperative preparation time; hematoma puncture under a 3D navigation mold is more personalized and shortens the intraoperative time course. There was no significant difference in therapeutic effect between the two groups.

Clinical study of percutaneous double-segment lengthened sacroiliac screws internal fixation via three-dimensional navigation technology in treatment of Denis type Ⅱ and Ⅲ sacral fractures

To investigate the effectiveness of percutaneous double-segment lengthened sacroiliac screws internal fixation assisted by three-dimensional (3D) navigation technology in treatment of Denis type Ⅱ and Ⅲ sacral fractures. A clinical data of 45 patients with the Denis type Ⅱ and Ⅲ sacral fractures admitted between January 2017 and May 2020 was retrospectively analyzed. There were 31 males and 14 females, with an average age of 48.3 years (range, 30-65 years). The pelvic fractures were all high energy injuries. According to the Tile classification standard, there were 24 cases of type C1, 16 cases of type C2, and 5 cases of type C3. The sacral fractures were classified as Denis type Ⅱ in 31 cases and type Ⅲ in 14 cases. The interval between injury and operation was 5-12 days (mean, 7.5 days). The lengthened sacroiliac screws were implanted in S 1 and S 2 segments respectively under the assistance of 3D navigation technology. The implantation time of each screw, the intraoperative X-ray exposure time, and the occurrence of surgical complications were recorded. After operation, the imaging reexamination was used to evaluate the screw position according to Gras standard and the reduction quality of sacral fractures according to Matta standard. At last follow-up, the pelvic function was scored with Majeed scoring standard. The 101 lengthened sacroiliac screws were implanted with the assisting of 3D navigation technology. The implantation time of each screw was 37.3 minutes on average (range, 30-45 minutes), and the X-ray exposure time was 46.2 seconds on average (range, 40-55 seconds). All patients had no neurovascular or organ injury. All incisions healed by first intention. The quality of fracture reduction was evaluated according to Matta standard as excellent in 22 cases, good in 18 cases, and fair in 5 cases, and the excellent and good rate was 88.89%. The screw position was evaluated according to Gras standard as excellent in 77 screws, good in 22 screws, and poor in 2 screws, and the excellent and good rate was 98.02%. All patients were followed up 12-24 months (mean, 14.6 months). All fractures healed and the healing time was 12-16 weeks (mean, 13.5 weeks). Pelvic function was evaluated according to Majeed scoring standard as excellent in 27 cases, good in 16 cases, fair in 2 cases, and the excellent and good rate was 95.56%. Percutaneous double-segment lengthened sacroiliac screws internal fixation for the treatment of Denis type Ⅱ and Ⅲ sacral fractures is minimally invasive and effective. With the assistance of 3D navigation technology, the screw implantation is accurate and safe.

Enhancing the depth perception of DSA images with 2D-3D registration.

Today, cerebrovascular disease has become an important health hazard. Therefore, it is necessary to perform a more accurate and less time-consuming registration of preoperative three-dimensional (3D) images and intraoperative two-dimensional (2D) projection images which is very important for conducting cerebrovascular disease interventions. The 2D-3D registration method proposed in this study is designed to solve the problems of long registration time and large registration errors in 3D computed tomography angiography (CTA) images and 2D digital subtraction angiography (DSA) images. To make a more comprehensive and active diagnosis, treatment and surgery plan for patients with cerebrovascular diseases, we propose a weighted similarity measure function, the normalized mutual information-gradient difference (NMG), which can evaluate the 2D-3D registration results. Then, using a multi-resolution fusion optimization strategy, the multi-resolution fused regular step gradient descent optimization (MR-RSGD) method is presented to attain the optimal value of the registration results in the process of the optimization algorithm. In this study, we adopt two datasets of the brain vessels to validate and obtain similarity metric values which are 0.0037 and 0.0003, respectively. Using the registration method proposed in this study, the time taken for the experiment was calculated to be 56.55s and 50.8070s, respectively, for the two sets of data. The results show that the registration methods proposed in this study are both better than the Normalized Mutual (NM) and Normalized Mutual Information (NMI). The experimental results in this study show that in the 2D-3D registration process, to evaluate the registration results more accurately, we can use the similarity metric function containing the image gray information and spatial information. To improve the efficiency of the registration process, we can choose the algorithm with gradient optimization strategy. Our method has great potential to be applied in practical interventional treatment for intuitive 3D navigation.

The clinical efficacy and safety of 3D vascular reconstruction combined with 3D navigation in laparoscopic hepatectomy.

The clinical efficacy and safety of 3D vascular reconstruction combined with 3D navigation in laparoscopic hepatectomy.

Development of a 3D Printed Brain Model with Vasculature for Neurosurgical Procedure Visualisation and Training

Simulation-based techniques using three-dimensional models are gaining popularity in neurosurgical training. Most pre-existing models are expensive, so we felt a need to develop a real-life model using 3D printing technology to train in endoscopic third ventriculostomy. The brain model was made using a 3D-printed resin mold from patient-specific MRI data. The mold was filled with silicone Ecoflex™ 00-10 and mixed with Silc Pig® pigment additives to replicate the color and consistency of brain tissue. The dura mater was made from quick-drying silicone paste admixed with gray dye. The blood vessels were made from a silicone 3D-printed mold based on magnetic resonance imaging. Liquid containing paprika oleoresin dye was used to simulate blood and was pumped through the vessels to simulate pulsatile motion. Seven residents and eight senior neurosurgeons were recruited to test our model. The participants reported that the size and anatomy of the elements were very similar to real structures. The model was helpful for training neuroendoscopic 3D perception and navigation. We developed an endoscopic third ventriculostomy training model using 3D printing technology that provides anatomical precision and a realistic simulation. We hope our model can provide an indispensable tool for young neurosurgeons to gain operative experience without exposing patients to risk.

The Evolution of Minimally Invasive Spine Tumor Resection and Stabilization: From K-Wires to Navigated One-Step Screws.

Minimization of the surgical approaches to spinal extradural metastases resection and stabilization was advocated by the 2012 Oncological Guidelines for Spinal Metastases Management. Minimally invasive approaches to spine oncology surgery (MISS) are continually advancing. This paper will describe the evolution of minimally invasive surgical techniques for the resection of metastatic spinal lesions and stabilization in a single institute. A retrospective analysis of patients who underwent minimally invasive extradural spinal metastases resection during the years 2013-2019 by a single surgeon was performed. Medical records, imaging studies, operative reports, rates of screw misplacement, operative time and estimated blood loss were reviewed. Detailed description of the surgical technique is provided. Of 138 patients operated for extradural spinal tumors during the study years, 19 patients were treated in a minimally invasive approach and met the inclusion criteria for this study. The mortality rate was significantly improved over the years with accordance of improve selection criteria to better prognosis patients. The surgical technique has evolved over the study years from fluoroscopy to intraoperative 3D imaging and navigation guidance and from k-wire screw insertion technique to one-step screws. Minimally invasive spinal tumor surgery is an evolving technique. The adoption of assistive devices such as intraoperative 3D imaging and one-step screw insertion systems was safe and efficient. Oncologic patients may particularly benefit from the minimization of surgical decompression and fusion in light of the frailty of this population and the mitigated postoperative outcomes associated with MIS oncological procedures.

3D Navigation is useful for posterior cervical foraminotomy, especially of the lower cervical spine

3D Navigation is useful for posterior cervical foraminotomy, especially of the lower cervical spine

Polarization Maintaining 3-D Convolutional Neural Network for Color Polarimetric Images Denoising

Color polarimetric imaging could provide multi-dimensional information that provides physical properties related to object shape, surface roughness, etc. Therefore, it has been widely used in various instrumentation and measurement applications, such as 3D measurement, surface detection, and navigation. However, compared to conventional color images, polarimetric images have a lower signal-to-noise ratio and are more sensitive to noise, which leads to unpleasant noisy images and destroys polarization analysis performance. Moreover, the multiple dimensions and physical relationships among dimensions make the issue of denoise more complicated and challenging. When denoising color polarimetric images, the coherence among the space, color, and polarization is significant but has not been fully exploited by existing methods. In this paper, we propose a three-dimensional (3D) convolutional neural network for denoising color polarimetric images. 3D convolutions are applied to extract information from multiple dimensions, i.e., the space, color, and polarization. In particular, we also found that 3D features derived from color polarimetric images still satisfy the Stokes relationship after 3D convolution. In other words, polarization properties are maintained. Experiments show that the proposed denoising method can well remove noises and restore polarization information in all channels. The proposed denoising method may find important applications for other multi-dimensional imaging tasks.