Publications
80 results found
Pratt P, Jaeger A, Hughes-Hallett A, et al., 2015, Robust ultrasound probe tracking: initial clinical experiences during robot-assisted partial nephrectomy, International Journal of Computer Assisted Radiology and Surgery, Vol: 10, Pages: 1905-1913, ISSN: 1861-6410
PurposeIn order to assist in the identification of renal vasculature and tumour boundaries in robot-assisted partial nephrectomy, robust ultrasound probe calibration and tracking methods are introduced. Contemporaneous image guidance during these crucial stages of the procedure should ultimately lead to improved safety and quality of outcome for the patient, through reduced positive margin rates, segmental clamping, shorter ischaemic times and nephron-sparing resection.MethodsSmall KeyDot markers with circular dot patterns are attached to a miniature pickup ultrasound probe. Generic probe calibration is superseded by a more robust scheme based on a sequence of physical transducer measurements. Motion prediction combined with a reduced region-of-interest in the endoscopic video feed facilitates real-time tracking and registration performance at full HD resolutions.ResultsQuantitative analysis confirms that circular dot patterns result in an improved translational and rotational working envelope, in comparison with the previous chessboard pattern implementation. Furthermore, increased robustness is observed with respect to prevailing illumination levels and out-of-focus images due to relatively small endoscopic depths of field.ConclusionCircular dot patterns should be employed in this context as they result in improved performance and robustness. This facilitates clinical usage and interpretation of the combined video and ultrasound overlay. The efficacy of the overall system is demonstrated in the first human clinical case.
Marcus HJ, Pratt P, Hughes-Hallett A, et al., 2015, Comparative effectiveness and safety of image guidance systems in neurosurgery: a preclinical randomized study, Journal of Neurosurgery, Vol: 123, Pages: 307-313, ISSN: 1933-0693
OBJECT: Over the last decade, image guidance systems have been widely adopted in neurosurgery. Nonetheless, the evidence supporting the use of these systems in surgery remains limited. The aim of this study was to compare simultaneously the effectiveness and safety of various image guidance systems against that of standard surgery.METHODS: In this preclinical, randomized study, 50 novice surgeons were allocated to one of the following groups: 1) no image guidance, 2) triplanar display, 3) always-on solid overlay, 4) always-on wire mesh overlay, and 5) on-demand inverse realism overlay. Each participant was asked to identify a basilar tip aneurysm in a validated model head. The primary outcomes were time to task completion (in seconds) and tool path length (in mm). The secondary outcomes were recognition of an unexpected finding (i.e., a surgical clip) and subjective depth perception using a Likert scale.RESULTS: The time to task completion and tool path length were significantly lower when using any form of image guidance compared with no image guidance (p < 0.001 and p = 0.003, respectively). The tool path distance was also lower in groups using augmented reality compared with triplanar display (p = 0.010). Always-on solid overlay resulted in the greatest inattentional blindness (20% recognition of unexpected finding). Wire mesh and on-demand overlays mitigated, but did not negate, inattentional blindness and were comparable to triplanar display (40% recognition of unexpected finding in all groups). Wire mesh and inverse realism overlays also resulted in better subjective depth perception than always-on solid overlay (p = 0.031 and p = 0.008, respectively).CONCLUSIONS: New augmented reality platforms may improve performance in less-experienced surgeons. However, all image display modalities, including existing triplanar displays, carry a risk of inattentional blindness.
King HK, Shang JS, Liu JL, et al., 2015, Micro-IGES Robot for Transanal Robotic Microsurgery., In The Hamlyn Symposium on Medical Robotics.
Hughes-Hallett A, Pratt P, Mayer E, et al., 2015, Using preoperative imaging for intraoperative guidance: a case of mistaken identity, International Journal of Medical Robotics and Computer Assisted Surgery, Vol: 12, Pages: 262-267, ISSN: 1478-596X
BACKGROUND: Surgical image guidance systems to date have tended to rely on reconstructions of preoperative datasets. This paper assesses the accuracy of these reconstructions to establish whether they are appropriate for use in image guidance platforms. METHODS: Nine raters (two experts in image interpretation and preparation, three in image interpretation, and four in neither interpretation nor preparation) were asked to perform a segmentation of ten renal tumours (four cystic and six solid tumours). These segmentations were compared with a gold standard consensus segmentation generated using a previously validated algorithm. RESULTS: Average sensitivity and positive predictive value (PPV) were 0.902 and 0.891, respectively. When assessing for variability between raters, significant differences were seen in the PPV, sensitivity and incursions and excursions from consensus tumour boundary. CONCLUSIONS: This paper has demonstrated that the interpretation required for the segmentation of preoperative imaging of renal tumours introduces significant inconsistency and inaccuracy. Copyright © 2015 John Wiley & Sons, Ltd.
Marcus HJ, Pratt P, Hughes-Hallett A, et al., 2015, Comparative effectiveness and safety of image guidance systems in surgery: a preclinical randomised study., Spring Meeting for Clinician Scientists in Training 2015, Publisher: Elsevier, Pages: S64-S64, ISSN: 0140-6736
BACKGROUND: Over the past decade image guidance systems have been widely adopted in specialties such as neurosurgery and otorhinolaryngology. Nonetheless, the evidence supporting the use of image guidance systems in surgery remains limited. New augmented reality systems offer the possibility of enhanced operating room workflow compared with existing triplanar image displays, but recent studies have highlighted several concerns, particularly the risk of inattentional blindness and impaired depth perception. The aim of this study was to compare simultaneously the effectiveness and safety of various image guidance systems against standard surgery. METHODS: In this preclinical randomised study design 50 novice surgeons were allocated to no image guidance, triplanar display, always-on solid overlay, always-on wire mesh overlay, or on-demand inverse realism overlay. Each participant was asked to identify a basilar tip aneurysm in a validated model head. The primary outcomes were time to task completion, and tool path length. The secondary outcomes were recognition of an unexpected finding (a surgical clip) and subjective depth perception (using a Likert scale). FINDINGS: Surgeons' time to task completion and tool path length were significantly lower in groups using any form of image guidance than in groups with no image guidance (p<0·001 and p=0·003, respectively). The tool path distance was also lower in groups using augmented reality than in those using triplanar display (p=0·010). Always-on solid overlay resulted in the greatest inattentional blindness (20% recognition of unexpected finding by all surgeons). Wire mesh and on-demand overlays mitigated but did not negate inattentional blindness, and were comparable with triplanar display (40% recognition of unexpected finding in all groups). Wire mesh and inverse realism overlays also resulted in better subjective depth perception than always-on solid overlay (p=0·031 and p=0·008, re
Hughes-Hallett A, Mayer EK, Pratt PJ, et al., 2015, Quantitative analysis of technological innovation in minimally invasive surgery, British Journal of Surgery, Vol: 102, Pages: e151-e157, ISSN: 1365-2168
BackgroundIn the past 30 years surgical practice has changed considerably owing to the advent of minimally invasive surgery (MIS). This paper investigates the changing surgical landscape chronologically and quantitatively, examining the technologies that have played, and are forecast to play, the largest part in this shift in surgical practice.MethodsElectronic patent and publication databases were searched over the interval 1980–2011 for (‘minimally invasive’ OR laparoscopic OR laparoscopy OR ‘minimal access’ OR ‘key hole’) AND (surgery OR surgical OR surgeon). The resulting patent codes were allocated into technology clusters. Technology clusters referred to repeatedly in the contemporary surgical literature were also included in the analysis. Growth curves of patents and publications for the resulting technology clusters were then plotted.ResultsThe initial search revealed 27 920 patents and 95 420 publications meeting the search criteria. The clusters meeting the criteria for in-depth analysis were: instruments, image guidance, surgical robotics, sutures, single-incision laparoscopic surgery (SILS) and natural-orifice transluminal endoscopic surgery (NOTES). Three patterns of growth were observed among these technology clusters: an S-shape (instruments and sutures), a gradual exponential rise (surgical robotics and image guidance), and a rapid contemporaneous exponential rise (NOTES and SILS).ConclusionTechnological innovation in MIS has been largely stagnant since its initial inception nearly 30 years ago, with few novel technologies emerging. The present study adds objective data to the previous claims that SILS, a surgical technique currently adopted by very few, represents an important part of the future of MIS.
Hughes-Hallet A, Mayer EK, Marcus HJ, et al., 2015, Inattention blindness in surgery, Surgical Endoscopy and Other Interventional Techniques, Vol: 29, Pages: 3184-3189, ISSN: 1432-2218
Dwyer G, Giataganas P, Pratt P, et al., 2015, A Miniaturised Robotic Probe for Real-Time Intraoperative Fusion of Ultrasound and Endomicroscopy, IEEE International Conference on Robotics and Automation (ICRA), Publisher: IEEE COMPUTER SOC, Pages: 1196-1201, ISSN: 1050-4729
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- Citations: 8
Hughes-Hallett A, Mayer E, Pratt P, et al., 2014, A census of robotic urological practice and training: a survey of the robotic section of the European Association of Urology., Journal of Robotic Surgery, Vol: 8, Pages: 349-355, ISSN: 1863-2483
To determine the current state of robotic urological practice, to establish how robotic training has been delivered and to ascertain whether this training was felt to be adequate. A questionnaire was emailed to members of the European Association of Urology robotic urology section mailing list. Outcomes were subdivided into three groups: demographics, exposure and barriers to training, and delivery of training. A comparative analysis of trainees and independently practising robotic surgeons was performed. 239 surgeons completed the survey, of these 117 (48.9 %) were practising robotic surgeons with the remainder either trainees or surgeons who had had received training in robotic surgery. The majority of robotic surgeons performed robotic-assisted laparoscopic prostatectomy (90.6 %) and were undertaking >50 robotic cases per annum (55.6 %). Overall, only 66.3 % of respondents felt their robotic training needs had been met. Trainee satisfaction was significantly lower than that of independently practising surgeons (51.6 versus 71.6 %, p = 0.01). When a subgroup analysis of trainees was performed examining the relationship between regular simulator access and satisfaction, simulator access was a positive predictor of satisfaction, with 87.5 % of those with regular access versus 36.8 % of those without access being satisfied (p < 0.01). This study reveals that a significant number of urologists do not feel that their robotic training needs have been met. Increased access to simulation, as part of a structured curriculum, appears to improve satisfaction with training and, simultaneously, allows for a proportion of a surgeon's learning curve to be removed from the operating room.
Bergeles C, Pratt P, Merrifield R, et al., 2014, Multi-view stereo and advanced navigation for transanal endoscopic microsurgery, Medical Image Computing and Computer-Assisted Intervention – MICCAI 2014, Publisher: Springer, Pages: 332-339
Transanal endoscopic microsurgery (TEM), i.e., the local excision of rectal carcinomas by way of a bimanual operating system with magnified binocular vision, is gaining acceptance in lieu of more radical total interventions. A major issue with this approach is the lack of information on submucosal anatomical structures. This paper presents an advanced navigation system, wherein the intraoperative 3D structure is stably estimated from multiple stereoscopic views. It is registered to a preoperatively acquired anatomical volume based on subject-specific priors. The endoscope motion is tracked based on the 3D scene and its field-of-view is visualised jointly with the preoperative information. Based on in vivo data, this paper demonstrates how the proposed navigation system provides intraoperative navigation for TEM1.
Hughes-Hallett A, Mayer E, Marcus HJ, et al., 2014, Quantifying innovation in surgery, Annals of Surgery, Vol: 260, Pages: 205-211, ISSN: 1528-1140
Objectives: The objectives of this study were to assess the applicability of patents and publications as metrics of surgical technology and innovation; evaluate the historical relationship between patents and publications; develop a methodology that can be used to determine the rate of innovation growth in any given health care technology.Background: The study of health care innovation represents an emerging academic field, yet it is limited by a lack of valid scientific methods for quantitative analysis. This article explores and cross-validates 2 innovation metrics using surgical technology as an exemplar.Methods: Electronic patenting databases and the MEDLINE database were searched between 1980 and 2010 for “surgeon” OR “surgical” OR “surgery.” Resulting patent codes were grouped into technology clusters. Growth curves were plotted for these technology clusters to establish the rate and characteristics of growth.Results: The initial search retrieved 52,046 patents and 1,801,075 publications. The top performing technology cluster of the last 30 years was minimally invasive surgery. Robotic surgery, surgical staplers, and image guidance were the most emergent technology clusters. When examining the growth curves for these clusters they were found to follow an S-shaped pattern of growth, with the emergent technologies lying on the exponential phases of their respective growth curves. In addition, publication and patent counts were closely correlated in areas of technology expansion.Conclusions: This article demonstrates the utility of publically available patent and publication data to quantify innovations within surgical technology and proposes a novel methodology for assessing and forecasting areas of technological innovation.
Hughes-Hallett A, Pratt P, Mayer E, et al., 2014, Image guidance for all-tilepro display of 3-dimensionally reconstructed images in robotic partial nephrectomy - REPLY, Urology, Vol: 84, Pages: 243-243, ISSN: 0090-4295
Hughes-Hallett A, Pratt P, Mayer E, et al., 2014, Image guidance for all-tilepro display of 3-dimensionally reconstructed images in robotic partial nephrectomy, Urology, Vol: 84, Pages: 237-242, ISSN: 0090-4295
ObjectiveTo determine the feasibility of a novel low-barrier-to-entry image guidance system.MethodsInitially a randomized crossover study was performed to establish the interface (iPad or 3-dimensional mouse) that minimized both the amount of time required to perform a manual image registration and the error of that registration. A subsequent clinical feasibility study was undertaken on 5 patients undergoing robot-assisted partial nephrectomy. Randomized crossover study primary outcomes were time to task completion, NASA–Task Load Index score, and alignment error (translational and rotational). The Mann-Whitney U test was used to compare groups. Surgeon feedback was sought when assessing the system in a clinical setting.ResultsIn the initial randomized crossover study, the iPad-based system was able to achieve adequate alignment accuracy (Frobenius norm of 0.3; total error of 20.8 mm) in significantly less time (33 seconds; P <.01) than the 3-dimensional mouse interface. The platform received good feedback from the operating surgeon in all instances with the surgeon commenting particularly on the improved appreciation of hilar vascular anatomy.ConclusionIn this study, we have demonstrated the feasibility of a “low-barrier-to-entry” image guidance system in a clinical setting. The system was able to achieve swift and sufficiently accurate alignment, with little impact on the surgical workflow.
Hughes-Hallett A, Mayer EK, Pratt P, et al., 2014, The current and future use of imaging in urological robotic surgery: a survey of the European Association of Robotic Urological Surgeons, International Journal of Medical Robotics and Computer Assisted Surgery, Vol: 11, Pages: 8-14, ISSN: 1478-596X
BackgroundWith the development of novel augmented reality operating platforms the way surgeons utilise imaging as a real-time adjunct to surgical technique is changing.MethodsA questionnaire was distributed via the European Robotic Urological Society mailing list. The questionnaire had three themes: surgeon demographics, current use of imaging and potential uses of an augmented reality operating environment in robotic urological surgery.Results117 of the 239 respondents (48.9%) were independently practising robotic surgeons. 74% of surgeons reported having imaging available in theatre for prostatectomy 97% for robotic partial nephrectomy and 95% cystectomy. 87% felt there was a role for augmented reality as a navigation tool in robotic surgery.ConclusionsThis survey has revealed the contemporary robotic surgeon to be comfortable in the use of imaging for intraoperative planning it also suggests that there is a desire for augmented reality platforms within the urological community.
Hughes-Hallett A, Pratt P, Mayer E, et al., 2014, Intraoperative Ultrasound Overlay in Robot-assisted Partial Nephrectomy: First Clinical Experience, European Urology, Vol: 65, Pages: 671-672, ISSN: 1421-993X
Intraoperative ultrasound facilitates the localisation of partially or entirely endophytic renal tumours during laparoscopic or robot-assisted partial nephrectomy (RAPN) [1]. A current limitation of intraoperative ultrasound is the requirement on the surgeon to relate the subsurface ultrasound image to the separate endoscopic view. Here we present the first clinical experience of live registered intraoperative ultrasound overlay.Registered ultrasound overlay was achieved using an approach previously described by our group, where the use of ultrasound in an ex vivo model for transanal microsurgery was examined [2]. This method of live image registration can be best described as a three-step process of calibration, image registration, and finally image overlay, and it has demonstrated a registration accuracy <0.5 mm [2]. Table 1 summarises the system hardware.
Hughes-Hallett A, Mayer EK, Marcus HJ, et al., 2014, Augmented reality partial nephrectomy: examining the current status and future perspectives, Urology, Vol: 83, Pages: 266-273, ISSN: 0090-4295
A minimal access approach to partial nephrectomy has historically been under-utilized, but is now becoming more popular with the growth of robot-assisted laparoscopy. One of the criticisms of minimal access partial nephrectomy is the loss of haptic feedback. Augmented reality operating environments are forecast to play a major enabling role in the future of minimal access partial nephrectomy by integrating enhanced visual information to supplement this loss of haptic sensation. In this article, we systematically examine the current status of augmented reality in partial nephrectomy by identifying existing research challenges and exploring future agendas for this technology to achieve wider clinical translation.
Edgcumbe P, Pratt P, Yang G-Z, et al., 2014, Pico Lantern: A Pick-up Projector for Augmented Reality in Laparoscopic Surgery, 17th International Conference on Medical Image Computing and Computer-Assisted Intervention (MICCAI), Publisher: SPRINGER INTERNATIONAL PUBLISHING AG, Pages: 432-+, ISSN: 0302-9743
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- Citations: 5
Pratt P, Bergeles C, Darzi A, et al., 2014, Practical intraoperative stereo camera calibration., Pages: 667-675
Many of the currently available stereo endoscopes employed during minimally invasive surgical procedures have shallow depths of field. Consequently, focus settings are adjusted from time to time in order to achieve the best view of the operative workspace. Invalidating any prior calibration procedure, this presents a significant problem for image guidance applications as they typically rely on the calibrated camera parameters for a variety of geometric tasks, including triangulation, registration and scene reconstruction. While recalibration can be performed intraoperatively, this invariably results in a major disruption to workflow, and can be seen to represent a genuine barrier to the widespread adoption of image guidance technologies. The novel solution described herein constructs a model of the stereo endoscope across the continuum of focus settings, thereby reducing the number of degrees of freedom to one, such that a single view of reference geometry will determine the calibration uniquely. No special hardware or access to proprietary interfaces is required, and the method is ready for evaluation during human cases. A thorough quantitative analysis indicates that the resulting intrinsic and extrinsic parameters lead to calibrations as accurate as those derived from multiple pattern views.
Pratt P, Bergeles C, Darzi A, et al., 2014, Practical Intraoperative Stereo Camera Calibration, 17th International Conference on Medical Image Computing and Computer-Assisted Intervention (MICCAI), Publisher: SPRINGER-VERLAG BERLIN, Pages: 667-675, ISSN: 0302-9743
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- Citations: 11
Marcus HJ, Hughes-Hallett A, Cundy TP, et al., 2013, Comparative Effectiveness of 3-D versus 2-D and HD versus SD Neuroendoscopy: A Preclinical Randomized Crossover Study, Neurosurgery
Sridhar AN, Hughes-Hallett A, Mayer EK, et al., 2013, Image-guided robotic interventions for prostate cancer, Nat Rev Urol, Vol: advance online publication, ISSN: 1759-4820
Robotic prostatectomy is a common surgical treatment for men with prostate cancer, with some studies estimating that 80% of prostatectomies now performed in the USA are done so robotically. Despite the technical advantages offered by robotic systems, functional and oncological outcomes of prostatectomy can still be improved further. Alternative minimally invasive treatments that have also adopted robotic platforms include brachytherapy and high-intensity focused ultrasonography (HIFU). These techniques require real-time image guidance-such as ultrasonography or MRI-to be truly effective; issues with software compatibility as well as image registration and tracking currently limit such technologies. However, image-guided robotics is a fast-growing area of research that combines the improved ergonomics of robotic systems with the improved visualization of modern imaging modalities. Although the benefits of a real-time image-guided robotic system to improve the precision of surgical interventions are being realized, the clinical usefulness of many of these systems remains to be seen.
Gao Q, Chang PL, Rueckert D, et al., 2013, Modeling of the bony pelvis from MRI using a multi-atlas AE-SDM for registrationand tracking in image-guided robotic prostatectomy, Computerized Medical Imaging and Graphics
Pratt P, Hughes-Hallett A, Di Marco A, et al., 2013, Multimodal reconstruction for image-guided interventions, Hamlyn Symposium on Medical Robotics, Pages: 59-60
Di Marco A, Pratt P, Yang G-Z, et al., 2013, A novel three-dimensional stereoscopic viewer for transanal endoscopic microsurgery: A report of two clinical cases, Hamlyn Symposium on Medical Robotics, Pages: 119-120
Marcus H, Hughes-Hallett A, Pratt P, et al., 2013, Operative working spaces in keyhole neurosurgery: An MRI study, Hamlyn Symposium on Medical Robotics, Pages: 91-91
Di Marco A, Pratt P, Jeyakumar J, et al., 2013, Validation of a novel three-dimensional stereoscopic viewer for transanal endoscopic microsurgery, Clinical Congress of the American College of Surgeons
Cohen DC, Pratt P, Sridhar AN, et al., 2012, First demonstrations of live augmented reality image guidance in robotic prostatectomy, EAU Robotic Urology Section Congress (ERUS), Publisher: WILEY-BLACKWELL, Pages: 132-133, ISSN: 1464-4096
Win Tun Latt, Tou Pin Chang, di Marco A, et al., 2012, A hand-held instrument for in vivo probe-based confocal laser endomicroscopy during minimally invasive surgery, Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on, Pages: 1982-1987, ISSN: 2153-0858
Cohen D, Sridhar A, Pratt P, et al., 2012, From bench to bedside: The novel use of 3D MRI for image-guided robotic prostatectomy, Hamlyn Symposium on Medical Robotics, Pages: 63-64
Pratt P, Edwards E, Arora A, et al., 2012, Image-guided transoral robotic surgery for the treatment of oropharyngeal cancer, Hamlyn Symposium on Medical Robotics, Pages: 21-22
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