Demonstration of Subretinal Injection Using Common-Path Swept Source OCT Guided Microinjector

Kang, Jin U.; Cheon, Gyeong Woo

doi:10.3390/app8081287

Cited by 22 publications

(15 citation statements)

References 28 publications

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“…We used a tremor compensation algorithm we developed earlier and more details can be found in our previous work. 13 A VH/GCL boundary, as well as a PR/CH layer boundary, were tracked, and one of them was used for depth targeting. We performed 12 trials of depth targeting each for VH/CGL and PR/CH boundaries using 5 eyes.…”

Section: Resultsmentioning

confidence: 99%

“… 5 – 9 Fiber-optic common-path OCT (CP-OCT) distal sensor integrated hand held surgical devices have also been developed to implement simple, compact, and cost-effective microsurgical systems. 10 – 13 In those systems, a single-fiber distal sensor attached to a surgical tooltip (i.e., needle or microforceps) guided the hand held surgical device by real-time A-scan-based surface tracking. However, surface tracking-based guidance could induce inaccurate depth targeting for subretinal injection because of retinal thickness variations and irregular morphological features caused by retinal diseases.…”

Section: Introductionmentioning

confidence: 99%

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CNN-based CP-OCT sensor integrated with a subretinal injector for retinal boundary tracking and injection guidance

Lee

Kang

2021

J. Biomed. Opt.

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. Significance: Subretinal injection is an effective way of delivering transplant genes and cells to treat many degenerative retinal diseases. However, the technique requires high-dexterity and microscale precision of experienced surgeons, who have to overcome the physiological hand tremor and limited visualization of the subretinal space. Aim: To automatically guide the axial motion of microsurgical tools (i.e., a subretinal injector) with microscale precision in real time using a fiber-optic common-path swept-source optical coherence tomography distal sensor. Approach: We propose, implement, and study real-time retinal boundary tracking of A-scan optical coherence tomography (OCT) images using a convolutional neural network (CNN) for automatic depth targeting of a selected retinal boundary for accurate subretinal injection guidance. A simplified 1D U-net is used for the retinal layer segmentation on A-scan OCT images. A Kalman filter, combining retinal boundary position measurement by CNN and velocity measurement by cross correlation between consecutive A-scan images, is applied to optimally estimate the retinal boundary position. Unwanted axial motions of the surgical tools are compensated by a piezoelectric linear motor based on the retinal boundary tracking. Results: CNN-based segmentation on A-scan OCT images achieves the mean unsigned error (MUE) of ( ) using an ex vivo bovine retina model. GPU parallel computing allows real-time inference ( ) and thus real-time retinal boundary tracking. Involuntary tremors, which include low-frequency draft in hundreds of micrometers and physiological tremors in tens of micrometers, are compensated effectively. The standard deviations of photoreceptor (PR) and choroid (CH) boundary positions get as low as when the depth targeting is activated. Conclusions: A CNN-based common-path OCT distal sensor successfully tracks retinal boundaries, especially the PR/CH boundary for subretinal injection, and automatically guides the tooltip’s axial position in real time. The microscale depth targeting accuracy of our system shows its promising possibility for clinical application.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

CNN-based CP-OCT sensor integrated with a subretinal injector for retinal boundary tracking and injection guidance

Lee

Kang

2021

J. Biomed. Opt.

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“…Although PID control requires significant computing power for the integrative part and this could slow down the whole system speed, this problem can be addressed by using GPU for data processing. Another possible method could be the use of a Kalman filter, which has been applied to the previous CP-SSOCT system for motion compensation and has the ability to catch up with the sensing speed [26]. Future experiments will include tests on the human cadaveric cornea with a larger sample size and evaluation of the final big bubble formation results.…”

Section: Discussionmentioning

confidence: 99%

“…The intraoperative OCT had been applied to the DALK procedure for verification of insertion depth of the needle [25]. Kang et al used the common-path OCT image to guide the microinjector for subretinal injection [26,27]. B-mode and C-mode OCT imaging have also been used to track various surgical tools underneath the tissue [28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Demonstration of Optical Coherence Tomography Guided Big Bubble Technique for Deep Anterior Lamellar Keratoplasty (DALK)

Guo

Sarfaraz

Gensheimer

et al. 2020

Sensors

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Deep anterior lamellar keratoplasty (DALK) is a highly challenging procedure for cornea transplant that involves removing the corneal layers above Descemet’s membrane (DM). This is achieved by a “big bubble” technique where a needle is inserted into the stroma of the cornea down to DM and the injection of either air or liquid. DALK has important advantages over penetrating keratoplasty (PK) including lower rejection rate, less endothelial cell loss, and increased graft survival. In this paper, we successfully designed and evaluated the optical coherence tomography (OCT) distal sensor integrated needle for a precise big bubble technique. We successfully used this sensor for micro-control of a robotic DALK device termed AUTO-DALK for autonomous big bubble needle insertion. The OCT distal sensor was integrated inside a 25-gauge needle, which was used for pneumo-dissection. The AUTO-DALK device is built on a manual trephine platform which includes a vacuum ring to fix the device on the eye and add a needle driver at an angle of 60 degrees from vertical. During the test on five porcine eyes with a target depth of 90%, the measured insertion depth as a percentage of cornea thickness for the AUTO-DALK device was 90.05 % ± 2.33 % without any perforation compared to 79.16 % ± 5.68 % for unassisted free-hand insertion and 86.20 % ± 5.31 % for assisted free-hand insertion. The result showed a higher precision and consistency of the needle placement with AUTO-DALK, which could lead to better visual outcomes and fewer complications.

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“…Our group [3] developed a motorized force-sensing microneedle by incorporating fiber Bragg grating (FBG) sensors into the tool tip to detect the puncture force. Kang et al [4] proposed a distance-sensing microinjector that used common-path swept source optical coherence tomography (OCT), for which an OCT fiber was attached to the tool tip to obtain the distance between the tool tip and the target vein wall. Ourak et al [5] integrated both FBG and OCT and attached the fibers on the tool tip to extract both distance and contact force as indicators of vein puncture.…”

Section: Introductionmentioning

confidence: 99%

Dual-Stiffness Force-Sensing Cannulation Tool for Retinal Microsurgery

Yang

Iordachita

2019

2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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Retinal vein cannulation is a promising treatment for retinal vein occlusion that involves the injection of an anticoagulant directly into the occluded vein to dissolve the blockage. However, excessive forces applied by the injection tool during the procedure, at either the scleral incision or injection site, can result in injury to the eye. Furthermore, the force required to puncture retinal veins (around 10 mN) is well below human sensing ability and an order of magnitude smaller than those that can be safely applied at the sclera (around 100 mN). Detection and management of toolto-tissue forces on these different scales are some of the most challenging aspects of the cannulation procedure. This work describes the development of a sensorized cannulation tool capable of detecting both tool-to-vein puncture forces and tool-to-sclera contact forces. By combining two materials, nitinol alloy for the tool tip and stainless steel for the tool shaft, to achieve dual stiffness, the tool possesses a flexible tip to capture small vein puncture forces and a stiffer shaft to maintain straightness during use. Three segments of fiber Bragg grating sensors are calibrated to measure the transverse forces at both the tool tip and sclerotomy, as well as to determine the tool insertion depth within the eye. The results of the validation experiments show that the root mean square error of the measurements for the force at the tip, the force at the sclerotomy, and the tool position are 0.70 mN, 1.59 mN, and 0.69 mm, respectively.

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Demonstration of Subretinal Injection Using Common-Path Swept Source OCT Guided Microinjector

Cited by 22 publications

References 28 publications

CNN-based CP-OCT sensor integrated with a subretinal injector for retinal boundary tracking and injection guidance

CNN-based CP-OCT sensor integrated with a subretinal injector for retinal boundary tracking and injection guidance

Demonstration of Optical Coherence Tomography Guided Big Bubble Technique for Deep Anterior Lamellar Keratoplasty (DALK)

Dual-Stiffness Force-Sensing Cannulation Tool for Retinal Microsurgery

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