Jinendra Ekanayake

All Publications

• Definition of Implanted Neurological Device Abandonment JAMA NETWORK OPEN Okun, M. S., Marjenin, T., Ekanayake, J., Gilbert, F., Doherty, S. P., Pilkington, J., French, J., Kubu, C., Lazaro-Munoz, G., Denison, T., Giordano, J. 2024; 7 (4): e248654

  Abstract

  Establishing a formal definition for neurological device abandonment has the potential to reduce or to prevent the occurrence of this abandonment.To perform a systematic review of the literature and develop an expert consensus definition for neurological device abandonment.After a Royal Society Summit on Neural Interfaces (September 13-14, 2023), a systematic English language review using PubMed was undertaken to investigate extant definitions of neurological device abandonment. Articles were reviewed for relevance to neurological device abandonment in the setting of deep brain, vagal nerve, and spinal cord stimulation. This review was followed by the convening of an expert consensus group of physicians, scientists, ethicists, and stakeholders. The group summarized findings, added subject matter experience, and applied relevant ethics concepts to propose a current operational definition of neurological device abandonment. Data collection, study, and consensus development were done between September 13, 2023, and February 1, 2024.The PubMed search revealed 734 total articles, and after review, 7 articles were found to address neurological device abandonment. The expert consensus group addressed findings as germane to neurological device abandonment and added personal experience and additional relevant peer-reviewed articles, addressed stakeholders' respective responsibilities, and operationally defined abandonment in the context of implantable neurotechnological devices. The group further addressed whether clinical trial failure or shelving of devices would constitute or be associated with abandonment as defined. Referential to these domains and dimensions, the group proposed a standardized definition for abandonment of active implantable neurotechnological devices.This study's consensus statement suggests that the definition for neurological device abandonment should entail failure to provide fundamental aspects of patient consent; fulfill reasonable responsibility for medical, technical, or financial support prior to the end of the device's labeled lifetime; and address any or all immediate needs that may result in safety concerns or device ineffectiveness and that the definition of abandonment associated with the failure of a research trial should be contingent on specific circumstances.

  View details for DOI 10.1001/jamanetworkopen.2024.8654

  View details for Web of Science ID 001225949400006

  View details for PubMedID 38687486

• Towards Real-time Multiplexed Bioimpedance Tumour-Tissue Margin Analysis Wong, S. S., Malik, A., Ekanayake, J., Constandinou, T. G., IEEE IEEE. 2023: 1-5

  Abstract

  Bioimpedance varies with physical tissue characteristics. As such it can be used for real-time tissue discrimination. This has led to its application as a surgical mapping tool to differentiate between healthy and abnormal tissue intraoperatively during tumour resection. Here, we build on previous work implementing a probe-based tetrapolar bioimpedance systems demonstrator, now extracting additional information for margin analysis with imperfect bioimpedance visibility. Through finite element analysis, we show preliminary findings using a single measurement with a multiplexed tetrapolar bioimpedance probe for identifying tissue boundaries, applied to porcine tissue as a surrogate for a tumour-tissue interface.

  View details for DOI 10.1109/EMBC40787.2023.10340781

  View details for Web of Science ID 001133788303128

  View details for PubMedID 38082946

• Patent: Apparatus and method for intraoperative real-time tumour tissue discrimination Ekanayake, J., Wong, S., Constandinou, T. US Patent Office. USA. 2023 ; US20230404423A1

  Abstract

  Apparatus for discriminating between tumour tissue and non-tumorous tissue in real-time, the apparatus comprising: a handheld bioimpedance probe having an elongate body and at least four stimulator electrodes mounted on a distal end of the elongate body, the electrodes being arranged to be held against a region of tissue in use; a current source configured to generate a stimulation current; a voltage sensor; a multiplexer coupled between the current source, the voltage sensor and the stimulator electrodes and configured to changeably switch between a plurality of switching configurations

• Patent: Actuator handle for surgical tools Ekanayake, J., Constandinou, T., Cavuto, M. US patent office. USA. 2023 ; US20230277192A1

  Abstract

  An actuator handle for a hand-held surgical tool, the actuator handle comprising: a body part adapted to be gripped by a user's hand, the body part having an end effector mounted or mountable thereon; an actuating member alongside the body part and arranged to be operably moveable by a single finger of the said hand, in a substantially linear manner between first and second positions relative to the body part, for actuating the end effector in use; and one or more coupling components coupled to the actuating member, for mechanically transmitting motive force from the actuating member to the end effector upon movement of the actuating member between the first and second positions by the user in use. A surgical clip, for example for use in aneurysm clipping, is also provided, the clip comprising: first and second clipping arms that are mutually openable and closable; biasing means arranged to resiliently bias the first and second clipping arms into a closed configuration; and first and second engagement fixtures respectively coupled to the first and second clipping arms and arranged such that first and second gripping arms of a complementary surgical clip deployment tool can grip the clip and open the clipping arms by applying a lateral force to the first and second engagement fixtures; wherein each of the first and second engagement fixtures comprises at least part of a ball or at least part of a loop or cup, with which each of the arms of said surgical clip deployment tool can engage in a substantially ball-and-socket manner.

• Multielectrode Multiplexing for Bioimpedance Surface Topography Mapping Wong, S. S., Radford, J., Faccio, D., Constandinou, T. G., Ekanayake, J., IEEE IEEE. 2023

  View details for DOI 10.1109/BioSensors58001.2023.10280912

  View details for Web of Science ID 001094618600023

• Multimodal Approaches for Real-time Mesoscopic Tissue Differentiation Wong, S. S., Radford, J., Binner, P., Gradauskas, V., Constandinou, T. G., Ekanayake, J., Faccio, D., IEEE IEEE. 2023

  View details for DOI 10.1109/BioSensors58001.2023.10281133

  View details for Web of Science ID 001094618600050

• Volitional Control of Brain Motor Activity and Its Therapeutic Potential NEUROMODULATION Girges, C., Vijiaratnam, N., Zrinzo, L., Ekanayake, J., Foltynie, T. 2022; 25 (8): 1187-1196

  Abstract

  Neurofeedback training is a closed-loop neuromodulatory technique in which real-time feedback of brain activity and connectivity is provided to the participant for the purpose of volitional neural control. Through practice and reinforcement, such learning has been shown to facilitate measurable changes in brain function and behavior.In this review, we examine how neurofeedback, coupled with motor imagery training, has the potential to improve or normalize motor function in neurological diseases such as Parkinson disease and chronic stroke. We will also explore neurofeedback in the context of brain-machine interfaces (BMIs), discussing both noninvasive and invasive methods which have been used to power external devices (eg, robot hand orthosis or exoskeleton) in the context of motor neurorehabilitation.The published literature provides mounting high-quality evidence that neurofeedback and BMI control may lead to clinically relevant changes in brain function and behavior.

  View details for DOI 10.1016/j.neurom.2022.01.007

  View details for Web of Science ID 000904207800015

  View details for PubMedID 35241365

• Olfactory outcomes after transsphenoidal endonasal surgery BRITISH JOURNAL OF NEUROSURGERY Baudracco, I., Ekanayake, J., Warner, E., Grieve, J. P., Dorward, N. L. 2020; 34 (1): 35-39

  Abstract

  Background: The endonasal approach is the gold standard for the resection of pituitary tumours, with either microscopic endonasal transsphenoidal (MET) or endoscopic endonasal transsphenoidal (EET) technique. Advantages and disadvantages of both techniques have been widely described in the literature, although limited attention has been paid to its impact on the sense of smell.Objective: The present study aims to quantify the effect of transnasal surgery on pituitary patients and examine olfactory outcomes.Methods: A prospective cohort study assessing the sense of smell of 20 patients (10 MET and 10 EET) pre-operatively. Olfactory function was re-assessed 6 months after surgery, using the University of Pennsylvania Smell Identification Test (Sensonics Inc., Haddon Heights, NJ).Results: The UPSIT (Sensonics Inc.) results showed a median pre-operative score of 33 (IQR 31-37.5) (normosmia). The median post-operative result was 25 (IQR 19.5-32), consistent with moderate microsmia. Twenty percent of the patients had normal olfactory function post-operatively, all of whom were from the EET group. Twenty percent had mild microsmia, equally divided in MET and EET subgroups. Seven patients had severe microsmia. Four patients were completely anosmic at 6 months follow-up.Conclusions: Patients undergoing a transsphenoidal procedure are at risk of olfactory disturbance post-operatively, which may include loss of the sense of smell. This information is relevant to the patients' perioperative experience, and should be incorporated into counselling with regards to outcomes and expectations. Although the study size is small, the study results suggest the ETS technique may be less traumatic for the olfactory function. A larger study powered to fully examine potential differences in olfactory outcomes following ETS and MTS is warranted.

  View details for DOI 10.1080/02688697.2019.1680798

  View details for Web of Science ID 000495568600001

  View details for PubMedID 31709822

• Volitional modulation of higher-order visual cortex alters human perception NEUROIMAGE Ekanayake, J., Ridgway, G. R., Winston, J. S., Feredoes, E., Razi, A., Koush, Y., Scharnowski, F., Weiskopf, N., Rees, G. 2019; 188: 291-301

  Abstract

  Can we change our perception by controlling our brain activation? Awareness during binocular rivalry is shaped by the alternating perception of different stimuli presented separately to each monocular view. We tested the possibility of causally influencing the likelihood of a stimulus entering awareness. To do this, participants were trained with neurofeedback, using realtime functional magnetic resonance imaging (rt-fMRI), to differentially modulate activation in stimulus-selective visual cortex representing each of the monocular images. Neurofeedback training led to altered bistable perception associated with activity changes in the trained regions. The degree to which training influenced perception predicted changes in grey and white matter volumes of these regions. Short-term intensive neurofeedback training therefore sculpted the dynamics of visual awareness, with associated plasticity in the human brain.

  View details for DOI 10.1016/j.neuroimage.2018.11.054

  View details for Web of Science ID 000460064700027

  View details for PubMedID 30529174

• Towards a Distributed, Chronically-Implantable Neural Interface Ahmadi, N., Cavuto, M. L., Feng, P., Leene, L. B., Maslik, M., Mazza, F., Savolainen, O., Szostak, K. M., Bouganis, C., Ekanayake, J., Jackson, A., Constandinou, T. G., IEEE IEEE. 2019: 719-724

  View details for DOI 10.1109/ner.2019.8716998

  View details for Web of Science ID 000469933200175

• An impedance probing system for real-time intraoperative brain tumour tissue discrimination Wong, S. S., Ekanayake, J., Liu, Y., Constandinou, T. G., IEEE IEEE. 2019

  View details for DOI 10.1109/biocas.2019.8918743

  View details for Web of Science ID 000521751500026

• Real-time decoding of covert attention in higher-order visual areas NEUROIMAGE Ekanayake, J., Hutton, C., Ridgway, G., Scharnowski, F., Weiskopf, N., Rees, G. 2018; 169: 462-472

  Abstract

  Brain-computer-interfaces (BCI) provide a means of using human brain activations to control devices for communication. Until now this has only been demonstrated in primary motor and sensory brain regions, using surgical implants or non-invasive neuroimaging techniques. Here, we provide proof-of-principle for the use of higher-order brain regions involved in complex cognitive processes such as attention. Using realtime fMRI, we implemented an online 'winner-takes-all approach' with quadrant-specific parameter estimates, to achieve single-block classification of brain activations. These were linked to the covert allocation of attention to real-world images presented at 4-quadrant locations. Accuracies in three target regions were significantly above chance, with individual decoding accuracies reaching upto 70%. By utilising higher order mental processes, 'cognitive BCIs' access varied and therefore more versatile information, potentially providing a platform for communication in patients who are unable to speak or move due to brain injury.

  View details for DOI 10.1016/j.neuroimage.2017.12.019

  View details for Web of Science ID 000427642800042

  View details for PubMedID 29247807

  View details for PubMedCentralID PMC5864512

• The conversational position in endoscopic pituitary surgery BRITISH JOURNAL OF NEUROSURGERY Ekanayake, J., Baudracco, I., Quereshi, A., Vercauteren, T., Dorward, N. L. 2018; 32 (1): 44-46

  Abstract

  We describe a novel patient position for endoscopic transphenoidal surgery - the 'conversational position'. This position is a safe and effective alternative to the standard supine position, incorporating a semi-sitting position with the additional innovation of achieving a 'conversational position' by flexing the neck and turning the patient's head turned to face the surgeon. The 'conversational' position offers improvements in the surgical approach to sellar region, addressing specific intraoperative challenges such as maintaining a bloodless operative field, and enabling more intuitive and ergonomic surgical workflow.

  View details for DOI 10.1080/02688697.2017.1406058

  View details for Web of Science ID 000433123300009

  View details for PubMedID 29199481

• Generalised Wasserstein Dice Score for Imbalanced Multi-class Segmentation Using Holistic Convolutional Networks Fidon, L., Li, W., Garcia-Peraza-Herrera, L. C., Ekanayake, J., Kitchen, N., Ourselin, S., Vercauteren, T., Crimi, A., Bakas, S., Kuijf, H., Menze, B., Reyes, M. SPRINGER INTERNATIONAL PUBLISHING AG. 2018: 64-76

  View details for DOI 10.1007/978-3-319-75238-9_6

  View details for Web of Science ID 000432603300006

• Preoperative Particle and Glue Embolization of Meningiomas: Indications, Results, and Lessons Learned from 117 Consecutive Patients NEUROSURGERY Borg, A., Ekanayake, J., Mair, R., Smedley, T., Brew, S., Kitchen, N., Samandouras, G., Robertson, F. 2013; 73: 244-251

  Abstract

  Preoperative embolization of meningiomas remains contentious, with persisting uncertainty over the safety and efficacy of this adjunctive technique.To evaluate the safety of presurgical embolization of meningiomas and its impact on subsequent transfusion requirement with respect to the extent of embolization and technique used.One hundred seventeen consecutive patients between 2001 and 2010 were referred for embolization of presumed intracranial meningioma before surgical resection. Glue and/or particles were used to devascularize the tumor in 107 patients, all of whom went on to operative resection. The extent and nature of embolization-related complications, degree of angiographic devascularization, and the intraoperative blood transfusion requirements were analyzed.Mean blood transfusion requirement during surgery was 0.8 units per case (range, 1-14 units). Blood transfusion was significantly lower in patients whose meningiomas were completely, angiographically devascularized (P = .035). Four patients had complications as a direct result of the embolization procedure. These included intratumoral hemorrhage in 2, sixth cranial nerve palsy in 1, and scalp necrosis requiring reconstructive surgery in 1 patient.The complication rate was 3.7%. No relationship between the embolic agent and the degree of devascularization was observed. Achieving a complete devascularization resulted in a lower blood transfusion requirement, considered an indirect measure of operative blood loss. This series demonstrates that preoperative meningioma embolization is safe and may reduce operative blood loss. We present distal intratumoral injection of liquid embolic as a safe and effective alternative to more established particle embolization techniques.

  View details for DOI 10.1227/NEU.0000000000000187

  View details for Web of Science ID 000330511600036

  View details for PubMedID 24077578

• Use of the novel ANSPACH bone collector for bone autograft in anterior cervical discectomy and cage fusion ACTA NEUROCHIRURGICA Ekanayake, J., Shad, A. 2010; 152 (4): 651-653

  Abstract

  The use of interbody cages with bone autograft following anterior cervical discectomy is well documented. The use of high-speed drills in the drilling of the posterior osteophyte results in the production of bone dust with viable osteophytes. We report the use of the ANSPACH bone collector device, which can be connected to standard suction circuitry and used to collect this bone dust.A group of six patients undergoing anterior cervical discectomies at one (4) or two levels (2). The bone collector was attached to the suction system. Following collection of the desired bone dust from the devices' collection chambers, it was fitted into the previously sized interbody cages and impacted into the disc spaces. The bone collector is a single-use, disposable device, delivered sterile, designed to connect to standard 6-mm suction tubing. The use of the bone collector provided sufficient bone material for complete filling of the interbody cages in all of the patients.The use of autogenous cancellous bone material is the gold standard with regards to bone graft. The collection of bone dust during the use of high-speed drills has a number of applications and could provide a useful source of viable osteogenic material in spinal, cranial and craniofacial procedures.The use of the ANSPACH bone collector incorporated into a standard suction system provides an efficient method of autograft collection, removing the need for an adjunctive procedure with associated donor-site morbidity.

  View details for DOI 10.1007/s00701-009-0513-0

  View details for Web of Science ID 000275945600012

  View details for PubMedID 19834643

• Lateralizing and localizing values of ictal onset recorded on the scalp:: Evidence from simultaneous recordings with intracranial foramen ovale electrodes EPILEPSIA Alarcón, G., Kissani, N., Dad, M., Elwes, R. D., Ekanayake, J., Hennessy, M. J., Koutroumanidis, M., Binnie, C. D., Polkey, C. E. 2001; 42 (11): 1426-1437

  Abstract

  The value of scalp recordings to localize and lateralize seizure onset in temporal lobe epilepsy has been assessed by comparing simultaneous scalp and intracranial foramen ovale (FO) recordings during presurgical assessment. The sensitivity of scalp recordings for detecting mesial temporal ictal onset has been compared with a "gold standard" provided by simultaneous deep intracranial FO recordings from the mesial aspect of the temporal lobe. As FO electrodes are introduced via anatomic holes, they provide a unique opportunity to record simultaneously from scalp and mesial temporal structures without disrupting the conducting properties of the brain coverings by burr holes and wounds, which can otherwise make simultaneous scalp and intracranial recordings unrepresentative of the habitual EEG.Simultaneous FO and scalp recordings from 314 seizures have been studied in 110 patients under telemetric presurgical assessment for temporal lobe epilepsy. Seizure onset was identified on scalp records while blind to recordings from FO electrodes and vice versa.Bilateral onset (symmetric or asymmetric) was more commonly found in scalp than in FO recordings. The contrary was true for unilateral seizure onset. In seizures with bilateral asymmetric onset on the scalp, the topography of largest-amplitude scalp changes at onset does not have localizing or lateralizing value. However, 75-76% of seizures showing unilateral scalp onset with largest amplitude at T1/T2 or T3/T4 had mesial temporal onset. This proportion dropped to 42% among all seizures with a unilateral scalp onset at other locations. Of those seizures with unilateral onset on the scalp at T1/T2, 65.2% showed an ipsilateral mesial temporal onset, and 10.9% had scalp onset incorrectly lateralized with respect to the mesial temporal onset seen on FO recordings. In seizures with a unilateral onset on the scalp at electrodes other than T1/T2, the proportions of seizures with correctly and incorrectly lateralized mesial temporal onset were 37.5 and 4.2%, respectively. Thus the ratio between incorrectly and correctly lateralized mesial temporal onsets is largely similar for seizures with unilateral scalp onset at T1/T2 (16.7%) and for seizures with unilateral scalp onset at electrodes other than T1/T2 (11.2%). The onset of scalp changes before the onset of clinical manifestations is not associated with a lower proportion of seizures with bilateral onset on the scalp, or with a higher percentage of mesial temporal seizures or of mesial temporal seizures starting ipsilateral to the side of scalp onset. In contrast, the majority (78.4%) of mesial temporal seizures showed clinical manifestations starting after ictal onset on FO recordings.A bilateral scalp onset (symmetric or asymmetric) is compatible with a mesial temporal onset, and should not deter further surgical assessment. Although a unilateral scalp onset at T1/T2 or T3/T4 is associated with a higher probability of mesial temporal onset, a unilateral onset at other scalp electrodes does not exclude mesial temporal onset. A unilateral scalp onset at electrodes other than T1/T2 is less likely to be associated with mesial temporal onset, but its lateralizing value is similar to that of unilateral scalp onset at T1/T2. The presence of clinical manifestations preceding scalp onset does not reduce the localizing or lateralizing values of scalp recordings.

  View details for DOI 10.1046/j.1528-1157.2001.46500.x

  View details for Web of Science ID 000172750500010

  View details for PubMedID 11879346