Fluidistic in phacophagy have long been a question for anterior-segment surgeons to obtain the more stable machine to operate. Nowadays, cataract surgery is becoming a standardised surgery with excellent statistical results due, among others, to an excellent stability of the anterior chamber depth and an excellent control of the machines. However, choosing the right machine continues to be questionable during vitrectomies, partially because retina surgeons are working in a wide cavity and they do not easily see their vitreous. Thus, the physical laws taking place in such situations are frequently underestimated. Pressiometric pumps, like the Venturi pumps are regulated through the Venturi rules in physics, with an aspiration flow indirectly controlled by the Vacuum: it is the so-called “Vacuum-control pumps” where a vacuum is created to secondarily obtain an aspiration. As a contrary, the Flowmetric pumps, like the Peristaltic pumps are working through the speed of the rollers to create a debit; the vacuum being only rising when this system is at it maximal debit, due to an occlusion or a strong resistance. For such reasons, we are mostly facing two main problems during our vitrectomies. First of all, when we start the aspiration flow, every machine have to face the height of the bottle that is creating an intraocular pressure inside the eye and push out, through our vitrectome probes, the intraocular components. Choosing the right machine is thus critical to avoid engaging retinal tissues. As an example, since Venturi pumps are always creating a vacuum to obtain a flow, this kind of machine is dangerous if we are very close to our target because our aspiration rate will be drastically elevated, even at the beginning, due to the addition of bottle height and vacuum creation. Beside of this first problem, we have also frequently to switch between saline and vitreous when vitrectomising, with different resistances. For such reasons, particularly in the periphery where we commonly need to come closer to our tissues, we can rapidly engage the retina with a venturi pump if we do not pay attention that we are entering into the vitreous again. However, if the machines should not make wide differences in specific, non-dangerous situations, a peristaltic machine should render the surgery smoother in complicated situations either when starting our core vitrectomy or when working in the periphery by reducing the flow rate differences when switching from saline to vitreous. If in most situations, driving a front- or a rear-wheel car does not make huge differences, in extreme conditions like on snow, we know why we will prefer the front-wheel cars. We thus will see why the author prefers to work with the peristaltic Eva machine from Dorc, preferring working safely in every situation to avoid problems in dangerous ones.

Contact Details:

Email: drkoch@docteurkoch.be
Cell Phone: +32496104081

Philippe Koch