Aylmore, Holly

Dimitrakakis, Emmanouil

Dwyer, George

Lindenroth, Lukas

Marcus, Hani

Stoyanov, Danail

English

UCL Discovery

Towards a Handheld Robotic Instrument for Minimally Invasive NeurosurgeryEmmanouil Dimitrakakis1, Holly Aylmore2, Lukas Lindenroth1, George Dwyer1,Hani J. Marcus1,3, and Danail Stoyanov11Wellcome/EPSRC Centre for Surgical and Interventional Sciences (WEISS), University College London (UCL), London, UK2Queen Square Institute of Neurology, University College London (UCL), London, UK3National Hospital for Neurology and Neurosurgery, London, UKINTRODUCTIONDue to its delicate subject matter and challenging oper-ations, neurosurgery has always been in need for adaptingnew techniques and technologies. A procedure that couldwidely benefit from robotic technology is the EndoscopicEndonasal Transsphenoidal Surgery (EETS). The EETSapproach is a minimally invasive neurosurgical techniquethat is performed via an anterior sphenoidotomy and aimsat the removal of sellar and parasellar lesions with the useof an endoscope and standard rigid instruments [1].In recent years, there has been an increased interest inthe Expanded Endoscopic Endonasal Approach (EEEA)that expands the EETS areas of interest [2]. Although apromising alternative to transcranial approaches that re-quire craniotomies and brain retraction, the EEEA comeswith its limitations. In [3], a number of surgeons wereasked about these technical challenges, with 74% ofthem identifying the limited surgical manipulation that thestandard non-articulated instruments offer as the biggestchallenge of this procedure.In this paper, current development of an ergonomicallydesigned handheld robotic instrument for the EEEA ispresented. The instrument employs a three degrees-of-freedom (DoF) robotic end-effector that provides accessto targets on the surface of the brain that were previouslyunattainable with rigid tools. It also incorporates a rotatingjoystick-body mechanism that can be placed at the optimalposition for the surgeon’s postural ergonomics, aimingto increase the efficacy of keyhole neurosurgery withoutburdening the surgeon with physiological problems.MATERIALS AND METHODSA. Development of the robotic end-effectorThe robotic end-effector aimed to be located at thedistal tip of this instrument is a 3-DoF, tendon-driven,spherical joint manipulator, with a diameter of 4mm and17.5mm length. A preliminary prototype of this miniaturemanipulator was fabricated and evaluated for its extendedworkspace and force capabilities in [4]. Based on theencouraging results from that preliminary design, the end-effector showcased in Fig. 1 was developed. This prototypewas 3D printed both in resin and metal, and is currentlyundergoing experimental evaluation.B. Development of the ergonomic handle1) Handle designs: Long-term use of tools that havenot been ergonomically designed can cause conditionsFig. 1: (a) DoF of a conventional tool, and (b). DoF ofthe miniature end-effector.such as carpal-tunnel syndrome [5]. Thus, appropriateergonomic tool design is essential. To avoid such compli-cations, the handle incorporated in the robotic instrumentshould be ergonomically designed, and ideally have a fastadoption rate, so that it can be easily integrated in thesurgical workflow. To cater to a large set of ergonomicliterature guidelines, two different handle concept proto-types were developed shown in Fig. 2.Fig. 2: (a) Experimental setup with renderings matchedto their respective prototypes. (b). The simulated environ-ment when a researcher is carrying out the peg-transfertask, and (c). The researcher holding the prototypes whencarrying out the peg-transfer task.The first handle is a forearm-mounted handle that mapsthe surgeon’s wrist degrees-of-freedom to that of therobotic end-effector [6]. This handle alleviates the surgeonof any wrist-fatigue and its intuitive movement mappingmakes it easily adoptable. The second handle is a joystick-and-trigger handle with a rotating body that places the joy-stick to the position most comfortable for the surgeon, at athumb abduction position. That position differs dependingon hand-size and right- or left-handedness, making the useof a rotating body a convenient solution.2) Randomised crossover user-study: The handles pre-sented in the previous section were incorporated into acustom-designed virtual surgical task simulator and wereassessed for their performance and ergonomics when com-pared with a standard neurosurgical grasper, to identify thesuperior handle design. The virtual task was performedby 9 novices with all 3 devices as part of a randomisedcrossover user-study. Their performance and ergonomicswere evaluated both subjectively by themselves and ob-jectively by a validated observational checklist [7].In terms of performance and efficacy, the two robotichandles clearly outperformed the standard neurosurgicalinstrument. Between the two, the concept prototypes hadvery similar behaviours. As far as their learning-curveswere concerned, the former was superior, whereas thelatter appeared to be more time-efficient after training.Finally, during their ergonomic assessment, the rotatingjoystick-body handle proved to be the safest device to usefor an extended amount of time according to a validatedergonomic measure.C. Handheld robotic instrument adaptationThe superior ergonomic results of the rotating joystick-body handle, combined with the increased time and effortit would take to switch between forearm-mounted instru-ments during the endonasal approach, indicate that themore favourable handle amongst the two, is the former.Thus, current development focuses on the incorporationof electronics and the previously presented robotic end-effector into a handle with a rotating joystick-body, toform a fully functional robotic instrument prototype. Arendering of this prototype is shown in Fig. 3.To incorporate electronics, as well as to create a robustcoupling between the handle body and the robotic end-effector, the concept prototype presented in Fig. 2(b).needed redesign. A translational, rather than a rotational,joystick is used to make the device more compact, whereasthe rotating joystick-body is now secured in place with alatch mechanism. The handle houses 3 miniature motorswith their encoder adapters and motor controllers (FAUL-HABER, Schönaich, Germany).It was fabricated with polylactic acid (PLA) plasticusing the desktop 3D printer Ultimaker S5 (Ultimaker,Geldermalsen, Netherlands). Fig. 3 showcases the proto-type handle body of the instrument as well as the end-effector fabricated in metal. With the development of thehandle body of the instrument now finalised, the focus hasshifted on the end-effector body.CONCLUSIONS AND DISCUSSIONIn this work, the current development of a novel hand-held robotic instrument for minimally invasive neuro-surgery was presented. The handle employs a miniatureFig. 3: Rendering of the robotic instrument, the metal end-effector, and a prototype of the actuating handle.robotic end-effector and an ergonomically designed han-dle, aiming to increase the efficacy of keyhole neuro-surgical approaches while also improving the proceduralergonomics associated with these complex procedures.In future work, the development of the robotised pro-totype will be finalised, and its performance will beevaluated in laboratory and clinical experiments. After theefficacy of the instrument has been validated, the devicewill be re-evaluated for its human factors aiming to havedeveloped a complete solution in terms of balance betweenperformance and improved ergonomics.REFERENCES[1] P. Cappabianca, L. M. Cavallo, and E. de Divitiis, “Endoscopicendonasal transsphenoidal surgery,” Neurosurgery, vol. 55, no. 4,pp. 933–941, 2004.[2] A. R. Dehdashti, A. Ganna, I. Witterick, and F. Gentili, “Ex-panded endoscopic endonasal approach for anterior cranial baseand suprasellar lesions: indications and limitations,” Neurosurgery,vol. 64, no. 4, pp. 677–689, 2009.[3] H. J. Marcus, T. P. Cundy, A. Hughes-Hallett, G.-Z. Yang, A. Darzi,and D. Nandi, “Endoscopic and keyhole endoscope-assisted neuro-surgical approaches: a qualitative survey on technical challenges andtechnological solutions,” British journal of neurosurgery, vol. 28,no. 5, pp. 606–610, 2014.[4] E. Dimitrakakis, G. Dwyer, L. Lindenroth, P. Giataganas, N. L. Dor-ward, H. J. Marcus, and D. Stoyanov, “A spherical joint robotic end-effector for the expanded endoscopic endonasal approach,” Journalof Medical Robotics Research, vol. 5, no. 03n04, p. 2150002, 2020.[5] P. Stoklasek, A. Mizera, M. Manas, and D. Manas, “Improvement ofhandle grip using reverse engineering, cae and rapid prototyping,”in MATEC Web of Conferences, vol. 76. EDP Sciences, 2016, p.02029.[6] E. Dimitrakakis, L. Lindenroth, G. Dwyer, H. Aylmore, N. L.Dorward, H. J. Marcus, and D. Stoyanov, “An intuitive surgicalhandle design for robotic neurosurgery,” International Journal ofComputer Assisted Radiology and Surgery, pp. 1–9, 2021.[7] E. Dimitrakakis, H. Aylmore, L. Lindenroth, G. Dwyer,J. Carmichael, D. Z. Khan, N. L. Dorward, H. J. Marcus,and D. Stoyanov, “Robotic handle prototypes for endoscopicendonasal skull base surgery: Pre-clinical randomised controlledtrial of performance and ergonomics,” Annals of BiomedicalEngineering, pp. 1–15, 2022.

Towards a Handheld Robotic Instrument for Minimally Invasive Neurosurgery

https://discovery.ucl.ac.uk/10150187/1/Dimitrakakis_et_al_CRAS2022.pdf

Towards a Handheld Robotic Instrument for Minimally Invasive Neurosurgery

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