Unintentional Movements During the Use of Vitreoretinal Forceps

Biomechanical considerations for optimising subretinal injections

Subretinal injection is the preferred delivery technique for various novel ocular therapies and is widely used because of its precision and efficient delivery of gene and cell therapies; however, choosing an injection point and defining delivery parameters to target a specified retinal location and area is an inexact science. We provide an overview of the key factors that play important roles during subretinal injections to refine the technique, enhance patient outcomes, and minimise risks. We describe the role of anatomical and physical variables that affect subretinal bleb propagation and shape and their impact on retinal integrity. We highlight the risks associated with subretinal injections and consider strategies to mitigate reflux and retinal trauma. Finally, we explore the emerging field of robotic assistance in improving intraocular manouvrability and precision to facilitate the injection procedure.

Ophthalmologists' assessment of the handling characteristics of the novel Finesse Reflex Handle in comparison to those of a conventional handle

Internal limiting membrane (ILM) peeling requires a delicate handling technique. It is also important that ophthalmologists can use the ILM forceps handle of their preference. This study objectively and subjectively evaluated the handling of the novel Finesse Reflex Handle (Reflex) in comparison with that of a conventional handle. The force required to close the forceps tips, evaluated using a digital force gauge, was significantly lesser for Reflex than for the conventional handle (3.14 ± 0.09 N vs. 3.84 ± 0.06 N, P < 0.001). Twenty-one ophthalmologists with various levels of experience answered a questionnaire after using both handles, and the total questionnaire score for Reflex was higher than that for the conventional handle (35.0 ± 3.7 vs. 30.0 ± 6.9, P = 0.01). Furthermore, the duration of experience as an ophthalmologist was negatively correlated with the vertical motion, assessed by video analysis, for the conventional handle (P = 0.02, r =  - 0.50) but not for Reflex (P = 0.26). In conclusion, objective and subjective analyses revealed that compared with the conventional handle, the novel Reflex handle had more favourable handling characteristics. Most ophthalmologists preferred the handling of Reflex. Reflex may compensate for a lack of surgical experience.

The Surgeon's Role in Inducing and Controlling Motion Errors During Intraocular Membrane Peeling Procedures

Objectives:

To understand the surgeon’s role in inducing and correcting movement inaccuracies during intraocular membrane peeling procedures.

Materials and Methods:

Optical sensors were used to record movement errors during actuation at the distal tip of 23-gauge pneumatic forceps both when the handle was handheld and when fixed with no human contact. Movements were also recorded at the proximal part of the forceps shaft (near the sclerotomy site) and compared to movement recorded at the distal end. The root mean square (RMS) and range values of the signals obtained from the sensors were calculated before and after applying high (7-13 Hz) and low (<5 Hz) frequency filters.

Results:

Comparison of RMS and range values of movement errors at the distal end of the forceps during actuation when the forceps handle was fixed and handheld showed that without human contact, these values were significantly lower in the X axis at all frequencies and in the Z axis at high frequencies compared to handheld (p<0.05), while there were no significant differences in the Y axis. Comparison of values from the distal and proximal ends of the forceps showed that when the forceps were fixed, RMS and range values were significantly higher for movement errors at the distal end compared to the proximal end at all frequencies (p<0.05). There was significant positive correlation between the extent of actuation and the RMS and range values for high-frequency movement errors but not low-frequency errors in all three axes with the fixed pneumatic handle (r=0.21-0.51, p<0.05).

Conclusion:

Surgeon- and non-surgeon-related errors are apparent in all axes, but skilled surgeons correct these errors through visual feedback, resulting in better correction in the visible planes. Sclerotomy sites provide a pivoting and stabilizing point for the shaft of the forceps and it is likely that skilled surgeons make use of the sclerotomy point to dampen motion errors, a skill worth teaching to beginners.

ROBOT-ASSISTED VITREORETINAL SURGERY IMPROVES SURGICAL ACCURACY COMPARED WITH MANUAL SURGERY: A Randomized Trial in a Simulated Setting

Robot-assisted vitreoretinal surgery increases precision and limits tissue damage compared with manual surgery especially for the novice surgeon. The Eyesi Simulator is a feasible platform for investigating robot-assisted vitreoretinal surgery.

Purpose:

To compare manual and robot-assisted vitreoretinal surgery using a virtual-reality surgical simulator.

Methods:

Randomized controlled crossover study. Ten experienced vitreoretinal surgeons and 10 novice ophthalmic surgeons were included. The participants were randomized to start with either manual or robot-assisted surgery. Participants completed a test session consisting of three vitreoretinal modules on the Eyesi virtual-reality simulator. The automated metrics of performance supplied by the Eyesi simulator were used as outcome measures. Primary outcome measures were time with instruments inserted (seconds), instrument movement (mm), and tissue treatment (mm²).

Results:

Robot-assisted surgery was slower than manual surgery for both novices and vitreoretinal surgeons, 0.24 SD units (P = 0.024) and 0.73 SD units (P < 0.001), respectively. Robot-assisted surgery allowed for greater precision in novices and vitreoretinal surgeons, −0.96 SD units (P < 0.001) and −0.47 SD units (P < 0.001), respectively. Finally, novices using robot-assisted surgery inflicted less tissue damage when compared with that using manual surgery, −0.59 SD units (P = 0.009).

Conclusion:

At the cost of time, robot-assisted vitreoretinal surgery seems to improve precision and limit tissue damage compared with that of manual surgery. In particular, the performance of novice surgeons is enhanced with robot-assisted vitreoretinal surgery.

A Microsurgical Vacuum Pick for Membrane Peeling Without Forceps During Vitreoretinal Surgery

BACKGROUND AND OBJECTIVE

To describe a new device and method for peeling membranes without forceps during vitreoretinal surgery.

MATERIALS AND METHODS

A novel micro-vacuum-pick (MVP) was used to peel internal limiting membrane (ILM) and/or epiretinal membrane (ERM) in 24 consecutive pars plana vitrectomy procedures. The MVP was used to create an edge in the membrane, strip the membrane from the retinal surface, and evacuate the membrane from the eye through the lumen of the device using active aspiration.

RESULTS

The MVP was the sole device used to peel and remove ILM and/or ERM in each case. No surgical complication occurred during any case. The MVP was used to perform the fluid-air exchange in all cases in which a fluid-air exchange was performed.

CONCLUSIONS

The MVP introduces a new method of peeling ILM and ERM without forceps. The MVP device and method eliminate the need for a separate device to create an edge in the ILM or ERM, reduce or eliminate instrument exchanges during membrane peeling, and eliminate the need for a separate extrusion cannula for fluid-air exchange. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:196-199.].