Publication History View all

  • [Show abstract] [Hide abstract]
    ABSTRACT: Endovascular techniques have been embraced as a minimally-invasive treatment approach within different disciplines of interventional radiology and cardiology. The current practice of endovascular procedures, however, is limited by a number of factors including exposure to high doses of X-ray radiation, limited 3D imaging, and lack of contact force sensing from the endovascular tools and the vascular anatomy. More recently, advances in steerable catheters and development of master/slave robots have aimed to improve these practices by removing the operator from the radiation source and increasing the precision and stability of catheter motion with added degrees-of-freedom. Despite their increased application and a growing research interest in this area, many such systems have been designed without considering the natural manipulation skills and ergonomic preferences of the operators. Existing studies on tool interactions and natural manipulation skills of the operators are limited. In this manuscript, new technical developments in different aspects of robotic endovascular intervention including catheter instrumentation, intra-operative imaging and navigation techniques, as well as master/slave based robotic catheterization platforms are reviewed. We further address emerging trends and new research opportunities towards more widespread clinical acceptance of robotically assisted endovascular technologies.
    Annals of Biomedical Engineering 11/2013; 42(4). DOI:10.1007/s10439-013-0946-8
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Although meningiomas of the spheno-orbital region commonly result in hyperostosis, intraosseous meningiomas, which feature extensive full thickness infiltration of the anterolateral skull base, are rare. In this study, we assess the value of image guidance during surgery for intraosseous spheno-orbital skull-base meningiomas in achieving safe and maximal abnormal bone resection. Method: Only cases with a full thickness and extensive intraosseous component were included. Image guidance was used to guide drilling of hyperostotic bone. Extensive resulting defects of the orbital wall were reconstructed with titanium mesh. Post-operative CT scans were used to assess completeness of abnormal bone resection in the skull base, and MRI scans used to evaluate residual intradural disease. Operative complications to neurovascular structures in adjacent foramina were recorded. Results: Nineteen patients with full-thickness intraosseous spheno-orbital meningiomas underwent image-guided resection. Anterior clinoidectomy to variable extent was necessary in 11 cases with decompression of the optic canal in five. In ten cases, hyperostotic bone was drilled from the middle fossa around the exit foramina of the trigeminal nerve and base of the pterygoid plates. Proptosis was corrected in all cases, and of 11 patients presenting with reduced visual acuity, symptoms improved or stabilized in ten cases. Post-operative CT scans confirmed gross resection of abnormal bone in all cases, but limited residual tumor was present around the cavernous sinus or orbital apex in eight patients. One patient died from a pulmonary embolism, the only mortality of the series. One patient had worsening of pre-existing poor visual acuity, and three patients had worsening of pre-existing ophthalmoplegia. Five patients developed new facial numbness post-operatively, which persisted in three cases. Conclusions: Intra-operative image guidance allowed total or near-total resection of the hyperostotic skull base around the cranial nerve foramina with minimal morbidity in a group of patients with extensive spheno-orbital meningiomas.
    Acta Neurochirurgica 03/2013; 155(6). DOI:10.1007/s00701-013-1662-8
  • [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: Since the first published work on natural orifice translumenal endoscopic surgery (NOTES) a decade ago, progress has been made in the domain of education and training, although questions posed by the original White Paper remain. This article aims to review the current status of education and training in NOTES. Methods: A review of the literature was conducted to evaluate the following: (1) What are the current training methods/modalities used for NOTES; what is the level of evidence to support their use? (2) How has NOTES clinical training been quantified; what is the evidence relating to performance of different NOTES operators? (3) What clinical NOTES training programs have been established and what are the wider training needs? Results: A total of 25 studies were included: 11 nonanimal studies, 8 animal studies, and 6 descriptions of education programs. Several animal and simulator models demonstrated construct validity, but no study showed human predictive validity. Logarithmic learning curves in animal models demonstrate 10 to 15 cases achieving a proficiency level. Current trends are that gastroenterologists prefer it for diagnostic and basic procedures, whereas surgeons prefer it for complex therapeutic cases. Conclusion: The development of a new specialty is intriguing but currently unviable. Training programs have been initiated, but information is limited; the common theme is surgeons receiving endoscopic training. Despite the research done, our knowledge of training and educating in NOTES procedures is limited, preventing a meta-analysis or formal review from being performed. Further research is needed to integrate NOTES into routine clinical procedure.
    Surgical Innovation 01/2013; 20(3). DOI:10.1177/1553350612474495
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Laser speckle contrast analysis (LASCA) is limited to being a qualitative method for the measurement of blood flow and tissue perfusion as it is sensitive to the measurement configuration. The signal intensity is one of the parameters that can affect the contrast values due to the quantization of the signals by the camera and analog-to-digital converter (ADC). In this paper we deduce the theoretical relationship between signal intensity and contrast values based on the probability density function (PDF) of the speckle pattern and simplify it to a rational function. A simple method to correct this contrast error is suggested. The experimental results demonstrate that this relationship can effectively compensate the bias in contrast values induced by the quantized signal intensity and correct for bias induced by signal intensity variations across the field of view.
    Biomedical Optics Express 01/2013; 4(1):89-104. DOI:10.1364/BOE.4.000089
  • Computerized medical imaging and graphics: the official journal of the Computerized Medical Imaging Society 12/2012; 36(8):589-90. DOI:10.1016/j.compmedimag.2012.08.003
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Sequential multispectral imaging is an acquisition technique that involves collecting images of a target at different wavelengths, to compile a spectrum for each pixel. In surgical applications it suffers from low illumination levels and motion artefacts. A three-channel rigid endoscope system has been developed that allows simultaneous recording of stereoscopic and multispectral images. Salient features on the tissue surface may be tracked during the acquisition in the stereo cameras and, using multiple camera triangulation techniques, this information used to align the multispectral images automatically even though the tissue or camera is moving. This paper describes a detailed validation of the set-up in a controlled experiment before presenting the first in vivo use of the device in a porcine minimally invasive surgical procedure. Multispectral images of the large bowel were acquired and used to extract the relative concentration of haemoglobin in the tissue despite motion due to breathing during the acquisition. Using the stereoscopic information it was also possible to overlay the multispectral information on the reconstructed 3D surface. This experiment demonstrates the ability of this system for measuring blood perfusion changes in the tissue during surgery and its potential use as a platform for other sequential imaging modalities.
    Biomedical Optics Express 10/2012; 3(10):2567-78. DOI:10.1364/BOE.3.002567
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Elastic light scattering spectroscopy (LSS) is widely utilized to investigate cellular structures in cultured cells and various tissues. However, few imaging systems, especially endoscopic imaging systems, can implement LSS. It is the aim of this work to create a polarized multispectral imaging system based around a rigid endoscope to detect micrometer sized particles using LSS. The instrument first validated with different sized mono-disperse polystyrene microspheres, then an image is reconstructed based on LSS which shows the differentiation of different sized microspheres. Finally a preliminary experiment is conducted to demonstrate its capability to discriminate different types of cells.
    Biomedical Optics Express 09/2012; 3(9):2087-99. DOI:10.1364/BOE.3.002087
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: The use of the flexible endoscope as a surgical platform potentially exposes a range of new surgical approaches and benefits yet to be fully defined. A new method using the flexible endoscope to undertake axillary dissection for breast cancer treatment is explored together with an investigation into its acceptability to the general public. Methods: Endoscopic axillary dissection via a transumbilical approach using the flexible endoscope passed subcutaneously from the umbilicus is described for four human cadaveric axillas. A questionnaire, validated by clinicians, explored the general public's reaction to the approach and how it might be influenced by potentially serious morbidity such as an increased rate of cancer recurrence. Results: All axillas were accessed successfully via the transumbilical approach. Levels 1 and 2 axillary dissection was attempted on four axillas. Scarring from previous axillary surgery prevented dissection in one case. In the remaining three cases, respectively 12, 11, and 14 lymph nodes were harvested. The operative times improved with each case, from 1080 to 390 min. A total of 127 people responded to the questionnaire, with 73 % preferring the described approach over the open and periareolar alternatives when morbidities were considered equivalent. When a hypothetical elevated risk of cancer recurrence was included with the transumbilical approach, one-fifth of the public still accepted the approach due to the likelihood of a superior cosmesis. Conclusion: The use of the flexible endoscope for oncologically safe levels 1 and 2 axillary dissection is possible and would be acceptable to the general public if it were clinically approved. However, significant challenges with the current endoscopic equipment and relevant instrumentation limit the potential of the technique. Technical innovation in terms of new instrument design with improved ergonomics will reduce long operating times and fatigue, thus ensuring surgical acceptance of the flexible endoscope.
    Surgical Endoscopy 08/2012; 27(2). DOI:10.1007/s00464-012-2461-7
  • [Show abstract] [Hide abstract]
    ABSTRACT: Longitudinal changes in cortical function are known to accompany motor skills learning, and can be detected as an evolution in the activation map. These changes include attenuation in activation in the prefrontal cortex and increased activation in primary and secondary motor regions, the cerebellum and posterior parietal cortex. Despite this, comparatively little is known regarding the impact of the mode or type of training on the speed of activation map plasticity and on longitudinal variation in network architectures. To address this, we randomised twenty-one subjects to learn a complex motor tracking task delivered across six practice sessions in either "free-hand" or "gaze-contingent motor control" mode, during which frontoparietal cortical function was evaluated using functional near infrared spectroscopy. Results demonstrate that upon practice termination, gaze-assisted learners had achieved superior technical performance compared to free-hand learners. Furthermore, evolution in frontoparietal activation foci indicative of expertise was achieved at an earlier stage in practice amongst gaze-assisted learners. Both groups exhibited economical small world topology; however, networks in learners randomised to gaze-assistance were less costly and showed higher values of local efficiency suggesting improved frontoparietal communication in this group. We conclude that the benefits of gaze-assisted motor learning are evidenced by improved technical accuracy, more rapid task internalisation and greater neuronal efficiency. This form of assisted motor learning may have occupational relevance for high precision control such as in surgery or following re-learning as part of stroke rehabilitation.
    NeuroImage 08/2012; 64C:267-276. DOI:10.1016/j.neuroimage.2012.08.056
  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Introduction: The drive to perform procedures with the least impact on the patient has meant that interest in natural orifice translumenal endoscopic surgery (NOTES) continues to proliferate. However, endoscope control within the extralumenal environment remains a significant challenge. This study aims to define a method to quantitatively assess endoscopic torque control as an indication of performance. Material and methods: Fourteen endoscopists performed a ten-target navigational task within a simulated NOTES environment whilst wrist movements were tracked with an optical motion tracker. Patterns of wrist movements were translated to a binary form enabling differentiation of the specified movement from no movement. Three patterns were discernable suggesting the discrimination of purposeful over random manipulations. Three independent assessors scored 140 patterns on a scale of 1 to 3 determined by which pattern was the most appropriate fit. Results: Mean score for novices was 16 (± 3) and for clinicians 22 (± 7). Inter-rater reliability (kappa statistic function) between the assessors ranged from 0.637 to 0.751 p < 0.001 referred to as a substantial assessment tool. The internal consistency between all variables using Chronbach's alpha function was 0.948 (p < 0.001). Conclusions: Pattern of movements extrapolated from the wrist can be used as a method of measuring endoscope torque control during a translumenal navigation task.
    Minimally invasive therapy & allied technologies: MITAT: official journal of the Society for Minimally Invasive Therapy 06/2012; 22(1). DOI:10.3109/13645706.2012.691638
Information provided on this web page is aggregated encyclopedic and bibliographical information relating to the named institution. Information provided is not approved by the institution itself. The institution’s logo (and/or other graphical identification, such as a coat of arms) is used only to identify the institution in a nominal way. Under certain jurisdictions it may be property of the institution.
View all

Top publications last week by reads

IEEE Transactions on Biomedical Engineering 03/2014; 61(5):1538-1554. DOI:10.1109/TBME.2014.2309951
24 Reads
International Workshop on Ubiquitous Computing for Pervasive Healthcare Applications (UbiHealth); 01/2004
17 Reads