Robotic ocular surgery

Vitreoretinal Surgical Instrument Tracking in Three Dimensions Using Deep Learning

Purpose

To evaluate the potential for artificial intelligence-based video analysis to determine surgical instrument characteristics when moving in the three-dimensional vitreous space.

Methods

We designed and manufactured a model eye in which we recorded choreographed videos of many surgical instruments moving throughout the eye. We labeled each frame of the videos to describe the surgical tool characteristics: tool type, location, depth, and insertional laterality. We trained two different deep learning models to predict each of the tool characteristics and evaluated model performances on a subset of images.

Results

The accuracy of the classification model on the training set is 84% for the x-y region, 97% for depth, 100% for instrument type, and 100% for laterality of insertion. The accuracy of the classification model on the validation dataset is 83% for the x-y region, 96% for depth, 100% for instrument type, and 100% for laterality of insertion. The close-up detection model performs at 67 frames per second, with precision for most instruments higher than 75%, achieving a mean average precision of 79.3%.

Conclusions

We demonstrated that trained models can track surgical instrument movement in three-dimensional space and determine instrument depth, tip location, instrument insertional laterality, and instrument type. Model performance is nearly instantaneous and justifies further investigation into application to real-world surgical videos.

Translational Relevance

Deep learning offers the potential for software-based safety feedback mechanisms during surgery or the ability to extract metrics of surgical technique that can direct research to optimize surgical outcomes.

Robotics and cybersurgery in ophthalmology: a current perspective

Ophthalmology is one of the most enriched fields, allowing the domain of artificial intelligence to be part of its point of interest in scientific research. The requirement of specialized microscopes and visualization systems presents a challenge to adapting robotics in ocular surgery. Cyber-surgery has been used in other surgical specialties aided by Da Vinci robotic system. This study focuses on the current perspective of using robotics and cyber-surgery in ophthalmology and highlights factors limiting their progression. A review of literature was performed with the aid of Google Scholar, Pubmed, CINAHL, MEDLINE (N.H.S. Evidence), Cochrane, AMed, EMBASE, PsychINFO, SCOPUS, and Web of Science. Keywords: Cybersurgery, Telesurgery, ophthalmology robotics, Da Vinci robotic system, artificial intelligence in ophthalmology, training on robotic surgery, ethics of the use of robots in medicine, legal aspects, and economics of cybersurgery and robotics. 150 abstracts were reviewed for inclusion, and 68 articles focusing on ophthalmology were included for full-text review. Da Vinci Surgical System has been used to perform a pterygium repair in humans and was successful in ex vivo corneal, strabismus, amniotic membrane, and cataract surgery. Gamma Knife enabled effective treatment of uveal melanoma. Robotics used in ophthalmology were: Da Vinci Surgical System, Intraocular Robotic Interventional Surgical System (IRISS), Johns Hopkins Steady-Hand Eye Robot and smart instruments, and Preceyes' B.V. Cybersurgery is an alternative to overcome distance and the shortage of surgeons. However, cost, availability, legislation, and ethics are factors limiting the progression of these fields. Robotic and cybersurgery in ophthalmology are still in their niche. Cost-effective studies are needed to overcome the delay. Technologies, such as 5G and Tactile Internet, are required to help reduce resource scheduling problems in cybersurgery. In addition, prototype development and the integration of artificial intelligence applications could further enhance the safety and precision of ocular surgery.

Evolution and Applications of Artificial Intelligence to Cataract Surgery

Topic

Despite significant recent advances in artificial intelligence (AI) technology within several ophthalmic subspecialties, AI seems to be underutilized in the diagnosis and management of cataracts. In this article, we review AI technology that may soon become central to the cataract surgical pathway, from diagnosis to completion of surgery.

Clinical Relevance

This review describes recent advances in AI in the preoperative, intraoperative, and postoperative phase of cataract surgery, demonstrating its impact on the pathway and the surgical team.

Methods

A systematic search of PubMed was conducted to identify relevant publications on the topic of AI for cataract surgery. Articles of high quality and relevance to the topic were selected.

Results

Before surgery, diagnosis and grading of cataracts through AI-based image analysis has been demonstrated in several research settings. Optimal intraocular lens (IOL) power to achieve the desired postoperative refraction can be calculated with a higher degree of accuracy using AI-based modeling compared with traditional IOL formulae. During surgery, innovative AI-based video analysis tools are in development, promoting a paradigm shift for documentation, storage, and cataloging libraries of surgical videos with applications for teaching and training, complication review, and surgical research. Situation-aware computer-assisted devices can be connected to surgical microscopes for automated video capture and cloud storage upload. Artificial intelligence-based software can provide workflow analysis, tool detection, and video segmentation for skill evaluation by the surgeon and the trainee. Mixed reality features, such as real-time intraoperative warnings, may have a role in improving surgical decision-making with the key aim of reducing complications by recognizing surgical risks in advance and alerting the operator to them. For the management of patient flow through the pathway, AI-based mathematical models generating patient referral patterns are in development, as are simulations to optimize operating room use. In the postoperative phase, AI has been shown to predict the posterior capsule status with reasonable accuracy, and can therefore improve the triage pathway in the treatment of posterior capsular opacification.

Discussion

Artificial intelligence for cataract surgery will be as relevant as in other subspecialties of ophthalmology and will eventually constitute a future cornerstone for an enhanced cataract surgery pathway.

Three-dimensional telesurgery and remote proctoring over a 5G network

Purpose

To present 2 cases of vitreoretinal surgery performed on a three-dimensional (3D) heads-up display surgical platform with real-time transfer of 3D video over a fifth-generation (5G) cellular network.

Methods

An epiretinal membrane peel and tractional retinal detachment repair performed at Massachusetts Eye and Ear in April 2019 were broadcast live to the Verizon 5G Lab in Cambridge, MA.

Results

Both surgeries were successful. The heads-up digital surgery platform, combined with a 5G network, allowed telesurgical transfer of high-quality 3D vitreoretinal surgery with minimal degradation. Average end-to-end latency was 250 ms, and average round-trip latency was 16 ms. Fine surgical details were observed remotely by a proctoring surgeon and trainee, with real-time communication via mobile phone.

Conclusions

This pilot study represents the first successful demonstration of vitreoretinal surgery transmitted over a 5G network. Telesurgery has the potential to enhance surgical education, provide intraoperative consultation and guidance from expert proctors, and improve patient outcomes, especially in remote and low-resource areas.

A review of robotic surgical training: establishing a curriculum and credentialing process in ophthalmology

Ophthalmic surgery requires a highly dexterous and precise surgical approach to work within the small confines of the eye, and the use of robotics offers numerous potential advantages to current surgical techniques. However, there is a lag in the development of a comprehensive training and credentialing system for robotic eye surgery, and certification of robotic skills proficiency relies heavily on industry leadership. We conducted a literature review on the curricular elements of established robotics training programs as well as privileging guidelines from various institutions to outline key components in training and credentialing robotic surgeons for ophthalmic surgeries. Based on our literature review and informal discussions between the authors and other robotic ophthalmic experts, we recommend that the overall training framework for robotic ophthalmic trainees proceeds in a stepwise, competency-based manner from didactic learning, to simulation exercises, to finally operative experiences. Nontechnical skills such as device troubleshooting and interprofessional teamwork should also be formally taught and evaluated. In addition, we have developed an assessment tool based on validated global rating scales for surgical skills that may be used to monitor the progress of trainees. Finally, we propose a graduating model for granting privileges to robotic surgeons. Further work will need to be undertaken to assess the feasibility, efficacy and integrity of the training curriculum and credentialing practices for robotic ophthalmic surgery.

Robotics and ophthalmology: Are we there yet?

Ophthalmology is a field that is now seeing the integration of robotics in its surgical procedures and interventions. Assistance facilitated by robots offers substantial improvements in terms of movement control, tremor cancellation, enhanced visualization, and distance sensing. Robotic technology has only recently been integrated into ophthalmology; hence, the progression is only in its initial stages. Robotic technologies such as da Vinci Surgical System are integrated into the field of ophthalmology and are assisting surgeons in complex eye surgeries. Ophthalmic surgeries require high accuracy and precision to execute tissue manipulation, and some complex ocular surgery may take few hours to complete the procedures that may predispose high-volume ophthalmic surgeons to work-related musculoskeletal disorders. A complete paradigm shift has been achieved in this particular field through the integration of advanced robotic technology, resulting in easier and more efficient procedures. Where robotic technology assists the surgeons and improves the overall quality of care, it also projects several challenges including limited availability, training, and the high cost of the robotic system. Although considerable studies and trials have been conducted for various robotic systems, only a few of them have made it to the commercial stage and ophthalmology, on its own, has a long way to go in robotics technology.

Vasovasostomy and vasoepididymostomy: Review of the procedures, outcomes, and predictors of patency and pregnancy over the last decade

BACKGROUND

In the era of improving assisted reproductive technology (ART), patients with obstructive azoospermia (OA) have 2 options: vasal repair or testicular sperm extraction with intracytoplasmic sperm injection. Vasal repair, including vasovasostomy (VV) and vasoepididymostomy (VE), is the only option that leads to natural conception.

METHODS

This article reviews the surgical techniques, outcomes, and predictors of postoperative patency and pregnancy, with a focus on articles that have reported over the last 10 years, using PubMed database searches.

MAIN FINDINGS

The reported mean patency rate was 87% and the mean pregnancy rate was 49% for a patient following microscopic VV and/or VE for vasectomy reversal. Recently, robot-assisted techniques were introduced and have achieved a high rate of success. The predictors and predictive models of postoperative patency and pregnancy also have been reported. The obstructive interval, presence of a granuloma, and intraoperative sperm findings predict postoperative patency. These factors also predict postoperative fertility. In addition, the female partner's age and the same female partner correlate with pregnancy after surgery.

CONCLUSION

In the era of ART, the physician should present and discuss with both the patient with OA and his partner the most appropriate procedure to conceive by using these predictors.

Toward Sclera-Force-Based Robotic Assistance for Safe Micromanipulation in Vitreoretinal Surgery

In vitreoretinal surgery instruments are inserted through the sclera to perform precise surgical maneuvers inside the eyeball, which exceeds typical human capabilities. Robotic assistance can enhance the skills of a novice surgeon, provide guidance during tool manipulation based on the desired behavior defined by expert surgeons' maneuvers, and consequently improve the surgical outcome. This paper presents an experimental study characterizing the safe/desired magnitude of forces between the surgical instrument and the sclera insertion port as a function of the tool insertion depth. We explore two types of regressions, a polynomial and a sum of sines fit, to describe the observed user behavior during our one-user pilot study, based on which a variable admittance control scheme can be implemented to robotically guide other users towards this desired behavior for a safe operation.

State of the art of robotic surgery related to vision: brain and eye applications of newly available devices

Background

Robot-assisted surgery has revolutionized many surgical subspecialties, mainly where procedures have to be performed in confined, difficult to visualize spaces. Despite advances in general surgery and neurosurgery, in vivo application of robotics to ocular surgery is still in its infancy, owing to the particular complexities of microsurgery. The use of robotic assistance and feedback guidance on surgical maneuvers could improve the technical performance of expert surgeons during the initial phase of the learning curve.

Evidence acquisition

We analyzed the advantages and disadvantages of surgical robots, as well as the present applications and future outlook of robotics in neurosurgery in brain areas related to vision and ophthalmology.

Discussion

Limitations to robotic assistance remain, that need to be overcome before it can be more widely applied in ocular surgery.

Conclusion

There is heightened interest in studies documenting computerized systems that filter out hand tremor and optimize speed of movement, control of force, and direction and range of movement. Further research is still needed to validate robot-assisted procedures.

Robotic Vitreoretinal Surgery

PURPOSE

To review the current literature on robotic assistance for ophthalmic surgery, especially vitreoretinal procedures.

METHODS

MEDLINE, Embase, and Web of Science databases were searched from inception to August, 2016, for articles relevant to the review topic. Queries included combinations of the terms: robotic eye surgery, ophthalmology, and vitreoretinal.

RESULTS

In ophthalmology, proof-of-concept papers have shown the feasibility of performing many delicate anterior segment and vitreoretinal surgical procedures accurately with robotic assistance. Multiple surgical platforms have been designed and tested in animal eyes and phantom models. These platforms have the capability to measure forces generated and velocities of different surgical movements. "Smart" instruments have been designed to improve certain tasks such as membrane peeling and retinal vessel cannulations.

CONCLUSION

Ophthalmic surgery, particularly vitreoretinal surgery, might have reached the limits of human physiologic performance. Robotic assistance can help overcome biologic limitations and improve our surgical performance. Clinical studies of robotic-assisted surgeries are needed to determine safety and feasibility of using this technology in patients.

Da Vinci Xi Robot-Assisted Penetrating Keratoplasty

PURPOSE

This study aims (1) to investigate the feasibility of robot-assisted penetrating keratoplasty (PK) using the new Da Vinci Xi Surgical System and (2) to report what we believe to be the first use of this system in experimental eye surgery.

METHODS

Robot-assisted PK procedures were performed on human corneal transplants using the Da Vinci Xi Surgical System. After an 8-mm corneal trephination, four interrupted sutures and one 10.0 monofilament running suture were made. For each procedure, duration and successful completion of the surgery as well as any unexpected events were assessed. The depth of the corneal sutures was checked postoperatively using spectral-domain optical coherence tomography (SD-OCT).

RESULTS

Robot-assisted PK was successfully performed on 12 corneas. The Da Vinci Xi Surgical System provided the necessary dexterity to perform the different steps of surgery. The mean duration of the procedures was 43.4 ± 8.9 minutes (range: 28.5-61.1 minutes). There were no unexpected intraoperative events. SD-OCT confirmed that the sutures were placed at the appropriate depth.

CONCLUSIONS

We confirm the feasibility of robot-assisted PK with the new Da Vinci Surgical System and report the first use of the Xi model in experimental eye surgery. Operative time of robot-assisted PK surgery is now close to that of conventional manual surgery due to both improvement of the optical system and the presence of microsurgical instruments.

TRANSLATIONAL RELEVANCE

Experimentations will allow the advantages of robot-assisted microsurgery to be identified while underlining the improvements and innovations necessary for clinical use.

ESPRESSO: A novel device for laser-assisted surgery of the anterior eye segment

INTRODUCTION

Merging robotics with laser eye surgery could enhance precision, repeatability and automation. During some eye laser procedures the patient is awake, thus eye stabilization is desired to avoid movements that could affect the treatment.

MATERIAL AND METHODS

The ESPRESSO platform has a two-stage actuation system to position a stabilization tool on the eye, a proximity sensing unit to monitor the stabilization tool position, and a sensing unit to monitor the pressure exerted on the eye. The platform is tested in-vitro and ex-vivo with clinicians. A maximum pressure to be exerted on the eye is defined with expert ophthalmic surgeons to be 22 mmHg: physiological intraocular pressure (IOP) range is 10-21 mmHg. This pressure corresponds to a force of 0.3 N.

RESULTS

The necessary contact force to have eye fixation (according to the clinicians' feedback) is evaluated: maximum values resulted always below 0.3 N. A maximum IOP increase of 4.67 mmHg is observed, that is a slight variation with respect to the performance of other platforms (IOP elevations up to 328 mmHg).

CONCLUSION

Design and initial assessment of the platform is presented. Eye stabilization is performed without exceeding the critical contact force value and causing large/sudden IOP increases.

Robot-Assisted Pterygium Surgery: Feasibility Study in a Nonliving Porcine Model

PURPOSE

This study aims to investigate the feasibility of pterygium surgery using the DaVinci Si HD robotic surgical system, and to describe a porcine model for pterygium surgery and evaluate its usefulness.

METHODS

The pterygium models were constructed using enucleated pig eyes and cold cuts. Robotically-assisted pterygium surgeries in nonliving biological pterygium models were performed using the DaVinci Si HD robotic surgical system. Twelve models were prepared, and 12 pterygium excision and conjunctival autografts were performed.

RESULTS

The DaVinci system provided the necessary dexterity to perform delicate ocular surface surgery and robotic tools were safe for the tissues. The mean duration of the surgical procedures was 36 minutes. There were no intraoperative complications and no unexpected events.

CONCLUSIONS

Robotic-assisted pterygium surgery is technically feasible for porcine eyes using the DaVinci Si HD robotic surgical system. The pterygium model that we describe could be of interest for surgical training.

TRANSLATIONAL RELEVANCE

Little research has been done in robotic microsurgery. Animal experimentation will allow the advantages of robotic-assisted microsurgery to be identified, while underlining the improvements and innovations necessary for clinical use.

Telerobotic contact transscleral cyclophotocoagulation of the ciliary body with the diode laser

To assess the feasibility of using the Robotic Slave Micromanipulator Unit (RSMU) to remotely photocoagulate the ciliary body for the treatment of glaucoma with the diode laser. In fresh unoperated enucleated human eyes, the ciliary body was destroyed either with a standard contact transscleral cyclophotocoagulation 'by hand' diode laser technique, or remotely using the RSMU. The treated sections were fixed in formalin, paraffin-embedded, and stained with hematoxylin and eosin. Histological evaluation was performed by a masked observer using a standardized grading system based on the amount of damage to the ciliary body to evaluate effectiveness of treatment. Both methods of contact transscleral cyclophotocoagulation showed therapeutic tissue disruption of the ciliary processes and both the non-pigmented and pigmented ciliary epithelium. Histology examination of remote robotic contact transscleral cyclophotocoagulation and "by hand" technique produced similar degrees of ciliary body tissue disruption. Remote diode laser contact transscleral cyclophotocoagulation of the ciliary body in fresh enucleated human eyes is possible with the RSMU. Therapeutic tissue disruption of the ciliary body was achieved. Additional study is necessary to determine the safety and efficacy of robotically-delivered cyclophotocoagulation in live eyes.

Robot-assisted intraocular surgery: development of the IRISS and feasibility studies in an animal model

PURPOSE

The aim of this study is to develop a novel robotic surgical platform, the IRISS (Intraocular Robotic Interventional and Surgical System), capable of performing both anterior and posterior segment intraocular surgery, and assess its performance in terms of range of motion, speed of motion, accuracy, and overall capacities.

PATIENTS AND METHODS

To test the feasibility of performing 'bimanual' intraocular surgical tasks using the IRISS, we defined four steps out of typical anterior (phacoemulsification) and posterior (pars plana vitrectomy (PPV)) segment surgery. Selected phacoemulsification steps included construction of a continuous curvilinear capsulorhexis and cortex removal in infusion-aspiration (I/A) mode. Vitrectomy steps consisted of performing a core PPV, followed by aspiration of the posterior hyaloid with the vitreous cutter to induce a posterior vitreous detachment (PVD) assisted with triamcinolone, and simulation of the microcannulation of a temporal retinal vein. For each evaluation, the duration and the successful completion of the task with or without complications or involuntary events was assessed.

RESULTS

Intraocular procedures were successfully performed on 16 porcine eyes. Four eyes underwent creation of a round, curvilinear anterior capsulorhexis without radialization. Four eyes had I/A of lens cortical material completed without posterior capsular tear. Four eyes completed 23-gauge PPV followed by successful PVD induction without any complications. Finally, simulation of microcannulation of a temporal retinal vein was successfully achieved in four eyes without any retinal tears/perforations noted.

CONCLUSION

Robotic-assisted intraocular surgery with the IRISS may be technically feasible in humans. Further studies are pending to improve this particular surgical platform.

A Novel Dual Force Sensing Instrument with Cooperative Robotic Assistant for Vitreoretinal Surgery

Robotic assistants and smart surgical instruments have been developed to overcome many significant physiological limitations faced by vitreoretinal surgeons, one of which is lack of force perception below 7.5 mN. This paper reports the development of a new force sensor based on fiber Bragg grating (FBG) with the ability to sense forces at the tip of the surgical instrument located inside the eye and also provide information about instrument interaction with the sclera. The sclera section provides vital feedback for cooperative robot control to minimize potentially dangerous forces on the eye. Preliminary results with 2×2 degree-of-freedom (DOF) sensor and force scaling robot control demonstrate significant reduction of forces on the sclera. The design and analysis of the sensor is presented along with a simulated robot assisted retinal membrane peeling on a phantom with sclera constraints and audio feedback.

Insertion force in manual and robotic corneal suturing

BACKGROUND

Due to differences in corneal grafting microsurgery between manual and robotic suturing, new challenges have arisen in testing the insertion force and torque of corneal tissue acting on suturing needles in order to guarantee successful completion of surgical procedures.

METHODS

In order to measure the force during the insertion operation, from the needle entering the cornea through the entry point until the puncturing of the exit point along the circular trajectory, a force measurement system was established, including fresh porcine cornea, a corneal-suturing robot, a circular needle, a micro-forceps manipulator with a force transducer, a computer with a data acquisition board and a medical microscope. The force values in the needle coordinate frames were obtained on the basis of a sensor coordinate frame through D-H coordinate transformation, and an index is proposed here to evaluate the insertion performance. Experiments on both manual and robotic suturing were carried out for comparison.

RESULTS

The scale and changes of the needle insertion force were obtained using two different suturing methods. The maximal tangent force in robotic suturing is a little larger than in manual suturing, and the maximal resultant force in robotic suturing is somewhat smaller. Although the difference is not very significant, robotic suturing performs in a more stable way. Moreover, the performance evaluation index M(dmax) (the maximum of square root of the quadratic sum of torque components M(OX) and M(OY)) in robotic suturing is much smaller than that in manual suturing.

CONCLUSIONS

The force measurement system has been verified to be feasible through experimentation. Compared with conventional manual surgery, robotic suturing has some advantages: more stable suturing, smaller distortion torque and fewer invasions to the corneal tissue, showing that its application in minimally invasive surgery is practical.

Evaluation of the motion of surgical instruments during intraocular surgery

PURPOSE

Robot assistance in ocular microsurgery could improve precision, dexterity, save time or prevent complications by task automation, and provide access to ocular surgery in undeserved countries by teleoperation. However, to design robotic devices, the range of motion of surgical instruments needs to be precisely quantified.

METHODS

An electromagnetic tracking system was developed for intraocular surgery in order to quantify the movements of ophthalmic surgeons. Kinematics of surgical steps during phacoemulsification and pars plana vitrectomy procedures were determined by measuring the maximum translation and angular range of motion of intraocular surgical tools in the three planes.

CONCLUSION

Important variations in amplitudes of rotation and translation were measured between both hands and between surgical tasks. These parameters may be used to develop a robotic intraocular surgical system or to improve training.

'The Microhand': a new concept of micro-forceps for ocular robotic surgery

PURPOSE

To test the feasibility of retinal manipulations using a new micromanipulator (Microhand) for ocular robotic microsurgery.

METHODS

Pneumatically actuated four-finger microhands were developed at UCLA with micro electromechanical systems (MEMS) technology to mimic a human hand for small object manipulation. Microhands with four 4 mm finger lengths were used for this study to lift caliper weights and fresh retinal tissue of porcine cadaver eyes to find the maximum force at a given pressure and feasibility of the microhands for retinal manipulation in real surgery.

RESULTS

A full closure of the microhand used for caliper weight lifting was achieved under 65 psi (448 kPa) of air pressure. The four-fingered microhand was able to develop about 20 mN of total lifting force and 5 mN per finger at 80 psi (551 kPa), and was strong enough to displace and lift the retina of pig eyes.

CONCLUSIONS

The microhand is able to apply calibrated forces to ocular tissues and is suitable for ocular microsurgical procedures. This new tool would be useful in the development of robotic microsurgery.