Browsing by Author "Nanayakkara, N.D."

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Hardware interface for haptic feedback in laparoscopic surgery simulators
(Institute of Electronics and Electrical Engineers(IEEE), 2014) Kannangara, S.M.; Ranasinghe, S.C.; Kumarage, S.K.; Nanayakkara, N.D.
Minimally Invasive Surgeries (MIS) such as laparoscopic procedures are increasingly preferred over conventional surgeries due to many different advantages. Laparoscopic surgical procedures are very complex compared to open surgeries and require high level of experience and expertise. Hybrid surgery simulators available for training using physical phantoms are expensive and not readily available in majority of health care facilities around the world. Therefore, computer simulation or Virtual Reality (VR) is a better way to obtain skills for MIS. A VR simulator incorporated with haptic feedback provides a comprehensive training closer to real world experience. In this paper, we present a novel approach to incorporate force feedback to VR laparoscopic surgery training. The proposed interface incorporates force feedback in all three axes to provide three levels of force feedback. Computational models of abdomen organs were generated using the cryosection data of Visible Human Project of the National Library of Medicine, USA. The organ models were developed with three basic force categories: soft, mild and hard. A hardware interface is developed to provide the force feedback for the interaction of virtual tools with the said organ models while generating the tool navigation information for the VR simulator. © 2014 IEEE.
Morphological variations of the human ejaculatory ducts in relation to the prostatic urethra
(Alan R. Liss, Inc, 2018) Malalasekera, A.P.; Sivasuganthan, K.; Sarangan, S.; Thaneshan, K.; Weerakoon, D.N.; Mathangasinghe, Y.; Gunasekera, C.L.; Mallawaarachchi, S.; Nanayakkara, N.D.; Anthony, D.J.; Ediriweera, D.
PURPOSE: Loss of ejaculation can follow transurethral resection of the prostate (TURP). Periverumontanal prostate tissue is preserved in ejaculation-preserving TURP (ep-TURP). Knowledge of ejaculatory duct anatomy in relation to the prostatic urethra can help in ep-TURP. This was evaluated in cross-sections of the prostate using a 3D model to determine a safe zone for resecting the prostate in ep-TURP. MATERIALS AND METHODS: A 3D reconstruction of the ejaculatory ducts was developed on the basis of six prostate gland cross-sections. The measurements obtained from the 3D model were standardized according to the maximum width of the prostate. Simple linear regressions were used to predict the relationships of the ejaculatory ducts. RESULTS: The maximum widths of the prostates ranged from 22.60mm to 52.10mm. The ejaculatory ducts entered the prostate with a concavity directed posterolaterally. They then proceeded towards the seminal colliculus in a fairly straight course, and from that point they angulated anteromedially. As they opened into the prostatic urethra they diverged. Significant regression models predicted the relationships of the ejaculatory ducts to the prostatic urethra based on the sizes of the prostates. CONCLUSIONS: The 3D anatomy of ejaculatory ducts can be predicted on the basis of prostate width. The ejaculatory ducts can be preserved with 95% accuracy if a block of tissue 7.5 mm from the midline on either side of the seminal colliculus is preserved, up to 10mm proximal to the level of the seminal colliculus, during TURP.
Simulating haptic feedback of abdomen organs on laparoscopic surgery tools
(International Academy Publishing (IAP), 2015) Kannangara, S.M.; Fernando, E.; Kumarage, S.K.; Nanayakkara, N.D.
AIMS: The study tested the hypothesis that a theory driven Diabetes Self-Management (DSM) intervention delivered by trained nurses would result in a clinically significant improvement in glycaemic control. METHODS: Patients with an HbA1c >7.5% (58mmol/mol) and free of diabetes complications were enrolled into a randomized controlled trial (n=85). Intervention consisted of four sessions and monthly follow up for 6 months. Biochemical tests, and diet and physical activity assessments were done in both groups. Analysis of covariance was used to test the effectiveness of the intervention. RESULTS: At 6 months, there was a significant difference (P=0.001) in HbA1c between the groups controlling for baseline values and other variables. Based on the primary outcome, 28% in the intervention group achieved the target value of 6.5% HbA1c, compared to 8% in the "usual care" group (P<0.001; η2=0.65). The reduction in total energy intake and increase in physical activity was significant in the intervention group between baseline and follow up. CONCLUSIONS: The DSM intervention has resulted in a clinically significant impact on glycaemia, change in diet and physical activity, and has demonstrated the feasibility of using it within existing care arrangements in a developing country setting. Copyright © 2015 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.