Depth-Supervised NeRF for Multi-View RGB-D Operating Room Images

Neural Radiance Fields (NeRF) is a powerful novel technology for the reconstruction of 3D scenes from a set of images captured by static cameras. Renders of these reconstructions could play a role in virtual presence in the operating room (OR), e.g. for training purposes. In contrast to existing systems for virtual presence, NeRF can provide real instead of simulated surgeries. This work shows how NeRF can be used for view synthesis in the OR. A depth-supervised NeRF (DS-NeRF) is trained with three or five synchronised cameras that capture the surgical field in knee replacement surgery videos from the 4D-OR dataset. The algorithm is trained and evaluated for images in five distinct phases before and during the surgery. With qualitative analysis, we inspect views synthesised by a virtual camera that moves in 180 degrees around the surgical field. Additionally, we quantitatively inspect view synthesis from an unseen camera position in terms of PSNR, SSIM and LPIPS for the colour channels and in terms of MAE and error percentage for the estimated depth. DS-NeRF generates geometrically consistent views, also from interpolated camera positions. Views are generated from an unseen camera pose with an average PSNR of 17.8 and a depth estimation error of 2.10%. However, due to artefacts and missing of fine details, the synthesised views do not look photo-realistic. Our results show the potential of NeRF for view synthesis in the OR. Recent developments, such as NeRF for video synthesis and training speedups, require further exploration to reveal its full potential.Comment: 12 pages, 4 figures, submitted to the 14th International Conference on Information Processing in Computer-Assisted Intervention

The role of cognitive abilities in laparoscopic simulator training

Learning minimally invasive surgery (MIS) differs substantially from learning open surgery and trainees differ in their ability to learn MIS. Previous studies mainly focused on the role of visuo-spatial ability (VSA) on the learning curve for MIS. In the current study, the relationship between spatial memory, perceptual speed, and general reasoning ability, in addition to VSA, and performance on a MIS simulator is examined. Fifty-three laparoscopic novices were tested for cognitive aptitude. Laparoscopic performance was assessed with the LapSim simulator (Surgical Science Ltd., Gothenburg, Sweden). Participants trained multiple sessions on the simulator until proficiency was reached. Participants showed significant improvement on the time to complete the task and efficiency of movement. Performance was related to different cognitive abilities, depending on the performance measure and type of cognitive ability. No relationship between cognitive aptitude and duration of training or steepness of the learning curve was found. Cognitive aptitude mediates certain aspects of performance during training on a laparoscopic simulator. Based on the current study, we conclude that cognitive aptitude tests cannot be used for resident selection but are potentially useful for developing individualized training programs. More research will be performed to examine how cognitive aptitude testing can be used to design training programs

Surgical Reintervention After Failed Antireflux Surgery: A Systematic Review of the Literature

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Ninety-day morbidity of robot-assisted redo surgery for recurrent rectal prolapse, mesh erosion and pelvic pain:lessons learned from 9 years' experience in a tertiary referral centre

Aim With increasing follow-up of patients treated with minimally invasive ventral mesh rectopexy (VMR) more redo surgery can be expected for recurrent rectal prolapse, mesh erosion and pelvic pain. The aim of this study is to evaluate the 90-day morbidity of robot-assisted redo interventions. Method All robot-assisted redo interventions after primary transabdominal repair of rectal prolapse between 2011 and 2019 were retrospectively analysed and compared with the results for patients after primary robot-assisted VMR during the same period. The redo interventions were divided into groups based on the indication for surgery (recurrent prolapse, mesh erosion, pelvic pain). Intraoperative complications and 90-day postoperative morbidity were evaluated. Results Three hundred and fifty nine patients were treated with primary VMR, with 73 for recurrent rectal prolapse, 12 for mesh erosion and 14 for pelvic pain. Complications of recurrent prolapse surgeries were comparable to those of primary VMR (p > 0.05). More intraoperative complications, minor and major complications were seen in redo surgery for erosion compared with primary VMR (23% vs. 3%, p = 0.01; 31% vs. 11%, p = 0.055; and 38% vs. 1%, p 0.05). Half of the patients with pelvic pain experienced relief of their symptoms. Conclusion Redo surgery for management of recurrent rectal prolapse is safe. Redo surgery for mesh erosion is associated with high morbidity rates. Redo surgery for pelvic pain can have major complications and is only effective in half of the cases

From Da Vinci Si to Da Vinci Xi:realistic times in draping and docking the robot

Robot-assisted surgery is assumed to be time consuming partially due to extra time needed in preparing the robot. The objective of this study was to give realistic times in Da Vinci Xi draping and docking and to analyse the learning curve in the transition from the Si to the Xi in an experienced team. This prospective study was held in a hospital with a high volume of robot-assisted surgery in general surgery, urology and gynaecology. Times from the moment patients entered the operating room until the surgeon took place behind console were precisely recorded during the first 6 weeks after the implementation of the Xi. In total, 65 procedures were performed and documented. The learning curve for the process of draping and docking the robot was reached after 21 and 18 cases, respectively. Mean times after completion of the learning curve were 5 min for draping and 7 min for docking and were statistically different from mean times before completion of the learning curve (p values <0.01). In dedicated teams netto extra time needed for preparing the Xi can even be reduced to just the time needed for docking. Thus, setting up the robot should have limited impact on overall time spent in the operation room

Sentinel node biopsy in prostate and bladder cancer using magnetic nanoparticles and a new magnetic detection technique

Sentinel node biopsy in prostate and bladder cancer using magnetic nanoparticles and a new magnetic detection techniqu