Pars Plana Vitrectomy and Scleral Buckling Surgery
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FEATURE Simulated ocular surgery: pars plana vitrectomy and scleral buckling surgery BY AHMED SALLAM AND RICHARD HAYNES n this second article on ocular realistic aspects of vitrectomy surgery that are actually required during surgery simulation, we will discuss that can be practiced and tested with vitrectomy, such as induction of how vitreoretinal surgery can be the Eyesi is the X-Y movement of the posterior vitreous detachment with Isimulated using high tech virtual microscope in concert with movement the cutter, cutting structures close reality modalities such as the Eyesi, of the eye. This is much more necessary to the retina with the scissors (Figure as well as other lower tech but very in vitreoretinal surgery than other 2) to simulate segmentation and versatile platforms such as model eyes. forms of intraocular surgery, because delamination steps, using forceps to The first part of the article will focus on of the need to obtain an optimum peel membranes and appropriate use pars plana vitrectomy simulation and view of the peripheral retina that can of the endolaser (Figure 3). then we will discuss simulated scleral only be achieved by movement of The other method for teaching PPV buckling surgery. the eye and microscope together in using simulation is model eyes. The Vitreoretinal (VR) surgery is the same direction. This step needs simulated ocular surgery model eyes different to other forms of intraocular a lot of practice by the vitreoretinal have been refined over a 15-year period surgery in several respects. Firstly, trainee until their ability to maintain by Craig Phillips (Phillips Studios), vitreoretinal surgery is usually more a centralised view becomes ‘second using a variety of materials that technically challenging and involves nature’. The Eyesi tries to establish this accurately replicate the look and, more more intricate steps, compared to, for skill and will penalise surgeons who importantly to a higher degree, the feel example, cataract surgery. Secondly, fail to move the eye and microscope of a human eye. The eyes developed as a vitreoretinal surgeon, one needs together and can actually prevent for pars plana vitrectomy are hollow to have a detailed knowledge of the progression through the various stages from inside and could be filled with technology used during surgery, such until this skill is honed. egg white to simulate human vitreous as vitrectomy machine parameters, When learning to perform (Figure 4). fluidics, intraocular tamponade, vitreoretinal surgery, trainees need Simulation of vitrectomy with the etc. Additionally, the likelihood to develop a sense of awareness model eyes not only complements that surgery will become more of instruments, position in the eye training achieved through practicing complicated or that the surgeon will relative to intraocular structures. on Eyesi, but also offers additional face unanticipated situations, is higher This could take time and often advantages through providing a more in vitreoretinal surgery than most complications such as inadvertent realistic and versatile simulation other forms of ocular surgery. Taken retinal touch or crystalline lens injury experience in learning pars plana together, these factors underscore are encountered more frequently in vitrectomy than the Eyesi, with the the importance of simulation training the learning phase. Training on the added benefit of being much cheaper in VR surgery to teach technical skills Eyesi can help the trainee to develop and more readily available. Creation and even more importantly to hone the this skill by simulating and recording of vitrectomy ports (Figure 5) and surgeon’s ability to deal with evolving damage to intraocular structures as suturing them, as well as inserting and unexpected situations. they occur. For example, crystalline the infusion cannula are very basic lens touch if instruments are reached and essential skills that trainees need Pars plana vitrectomy too far across the midline and bleeding to learn at the beginning of their The Eyesi VR module allows simulation of the retina if it is inadvertently vitreoretinal training and cannot be and the objective assessment of many touched. taught using the Eyesi but could easily of the steps involved in pars plana Vitreoretinal surgery requires a be practiced on model eyes. vitrectomy (PPV) surgery. Just like high degree of manual dexterity. The model eye can also simulate in the cataract module, each task is The Eyesi forces the surgeon to manoeuvres such as removal of the objectively scored, giving simultaneous use their non-dominant hand to egg white ‘vitreous’ with a vitrectomy feedback and a detailed score looking perform manoeuvres, encouraging cutter and light pipe or even peeling at various aspects of the manoeuvre the flexibility that is often required. simulated epiretinal membranes, or such as microscope and instrument The initial stages of the vitreoretinal insertion of a scleral buckle during handling, economy of movement, and module helps the surgeon to vitrectomy. Removal of a dense completion of the task without causing become familiar with using bimanual vitreous haemorrhage can also be inadvertent tissue damage (Figure 1). techniques with various abstract tasks, simulated by adding red food dye to One of the most important and and then progress on to manoeuvres the egg white (Figure 6). These forms eye news | AUGUST/SEPTEMBER 2015 | VOL 22 NO 2 | www.eyenews.uk.com FEATURE Figure 2: Ocurring Figure 1: Eyesi structures close abstract task. to the retina. Figure 4: Figure 3: Eyesi Vitrectomy eye endolaser. with ERM. Figure 6: Figure 5: Vitrectomy Inserting scleral for vitreous ports. haemorrhage. Figure 7: SOS vitrectomy simulation. Figure 8: Basic scleral buckling eye. eye news | AUGUST/SEPTEMBER 2015 | VOL 22 NO 2 | www.eyenews.uk.com FEATURE of simulation enable trainees to become The use of simulation to learn SB is, familiar with the vitrectomy machine, in our view, a highly desirable step for light pipe, cutter, operating microscope every vitreoretinal trainee for a variety and wide angle viewing system or of reasons. Firstly, data from the UK contact lens, which they will be using for shows a steady decline in the number live surgery (Figure 7). of SB operations performed in the UK Unplanned events and intraoperative in the last 15 years [1]. This trend has complications during vitreoretinal also been seen worldwide [2-3]. The surgery represent a challenge for the paucity of SB cases means that trainees accomplished vitreoretinal surgeon, let will not have the chance to properly alone the novice one. It is much better develop the skills required for this that surgeons are trained to deal with surgery. Simulation is therefore very these events away from patients but in important to make sure that a trainee Figure 9: Practising indentation. an environment that is close to real-life. has practiced these techniques in a The use of model eyes provides such a safe environment, has demonstrated valuable experience. For example, the their competence and can therefore mentor can pull the infusion cannula take advantage of the opportunities out of the eye and get their student to to perform SB surgery when they identify the source of hypotony and then arise. Secondly, in the era of small teach them how to best and efficiently incision cataract surgery, trainees do manage this situation. not have many opportunities to hone Currently, Phillips Studios is working their tissue dissection and suturing on the development of a model eye skills, and even if they are not going to which can be used to practice indirect become vitreoretinal surgeons these and endolaser techniques. This is a skills will stand them in good stead very welcome addition, particularly for whatever branch of ophthalmic as mastering indirect laser is not a surgery they specialise in. In addition, very straightforward skill to learn many quite senior trainees feel outside Figure 10: Suturing a scleral buckle. and does require a lot of practice, their comfort zone when performing an discussion and advice to optimise the indentation examination of the eye with technique. The eyes showcased on the indirect ophthalmoscope (Figure 9) the Simulated Ocular Surgery website and improving these skills to the point have been used for teaching all over where they do not have to consciously the world by trainees for solo practice think which direction to move the and in workshops and training courses, indentor will improve their preoperative including the Duke University Advanced assessment of patients, as well as their Vitreoretinal Course in the US. surgical technique in theatre. When teaching our trainees to Scleral buckling perform SB on model eyes, we use the There are two types of model eyes than basic eye to practice locating the retinal can be used to simulate scleral buckling break by indentation examination (SB) surgery: with an indirect ophthalmoscope Figure 11: Suturing an encircling band. 1. The basic vitreoretinal eye: this and marking the break location on model eye has no conjunctiva the outside of the eye, placing sling nor Tenon’s capsule. It has four sutures around the rectus muscles, rectus muscles but has no oblique scleral buckle suturing and knot tying Rubric (OSSCAR) for SB surgery. The muscles. The globe is hollow, at the appropriate tension to create an scoring system is self-explanatory and has an internal ‘retinal tear’ adequate indent (Figure 10). All of which and includes a global assessment of that can be seen with an indirect allow the trainee to get a feel for the tissue handling, instrument handling ophthalmoscope and is the target tissues and build up their confidence and knot tying. A PDF of this OSSCAR location for the scleral buckle (Figure with these manoeuvres. This is best can be downloaded from www. 8). The sclera has been made out done initially in a one to one setting simulatedocularsurgery.com of a material that has the same with the trainer, after which the trainee In a similar way to how we teach resistance to a needle pass as human can take the head and eyes home to cataract surgery, VR mentors can build sclera and has a similar tensile practice.