(1)
St. Johns, FL, USA
(2)
Helen Keller Foundation for Research and Education, International Society of Ocular Trauma, Birmingham, AL, USA
(3)
Consultant and Vitreoretinal Surgeon, Milos Eye Hospital, Belgrade, Serbia
(4)
Consultant and Vitreoretinal Surgeon, Zagórskiego Eye Hospital, Cracow, Poland
4.1 What If the Surgeon Has Tremor?
The less experienced a fellow, the more he is worried about his tremor: will it interfere with surgical success? Below are a few thoughts about tremor:
It is exceptional that a surgeon has absolutely no visible tremor – and even then it may simply escape easy detection.
Tremor is not a constant phenomenon. Whether it is present during a particular operation depends on several factors.
The surgeon’s mental status. Tremor may not appear under certain circumstances1 but readily manifests itself if the stakes are assumed to be higher.2
Acute sympathomimetic reaction due to increased caffeine intake, medications, or unexpected news.3
Straining.4
Lack of rest the previous night (length, quality, alcohol consumption).
The setup at the operating table: wrist or hand support (see Sect. 16.2).
Even if tremor is present, it need not necessarily interfere with the hands’ ability to properly execute the brain’s commands. The negative implications of the same amplitude of tremor depend on the surgeon’s experience.
Pearl
The more experienced the surgeon, the less the tremor interferes with surgical success.
The surgeon is able to reduce the level of tremor by having proper hand (wrist) support and by consciously and constantly paying attention to not squeezing the instruments he is holding.
Squeezing non-squeezable instruments (see Sect. 13.2) such as the light pipe obviously serves no purpose, yet inexperienced surgeons do this instinctively. It should be part of the fellow’s training to fight this reflex.
Not all squeezable instruments are the same.5 A good example is the disposable vs the permanent VR forceps (see Fig. 13.5). To operate the forceps the surgeon must squeeze its handle. The permanent forceps requires minimal force because (1) the traveling distance of the handle from “jaws completely open” to “jaws completely closed” is short and (2) its resistance to the squeezing is low. Neither is true with the disposable forceps.6
Q and A
Q
What can the surgeon do if, despite his best efforts, tremor seems unstoppable and appears to prevent successful execution of a maneuver?
A
An individual decision is necessary whether the risk of attempting vs abandoning the maneuver is greater. Alternatively, the surgeon can try to switch the order of maneuvers and return to the delicate one (e.g., ILM peeling) later during the operation, first performing tasks that require less dexterity (e.g., scleral indentation and peripheral vitrectomy).
A final issue regarding tremor concerns its impact on the surgeon’s lifestyle. Can he repeatedly strain his hands/arms with hard physical work (daily weight lifting in the gym) or must he refrain from such activities?7
Again, the answer varies based on the individual surgeon. Some people are able to perform fine intravitreal work perfectly even after hard physical work; others have a major increase of tremor even after mild physical activity.8 Keep in mind, though, that repeated hard physical work does reduce the ability of one’s fingers to carry out fine manipulations. VR surgeons should not do heavy weight lifting on a long-term basis.
4.2 How Important Is Good Dexterity?
Again, it must be emphasized that the brain is the boss; the hands simply execute the instructions coming from the cortex. No matter how good a surgeon is with his hands: if the command is erroneous, the outcome is poor (see also Chap. 1).
Very few people have two hands with equal dexterity; it is no different with VR surgeons. Typically, the surgeon is right-handed and would not be able to do the finest of maneuvers9 with his left hand unless undergoing rigorous, lengthy training.
Typically, the surgeon’s nondominant hand is used for performing maneuvers that require only limited dexterity.
In monomanual surgery, the nondominant hand usually holds the light pipe only. It may, however, be also needed for vitreous removal in the periphery in a phakic eye but also during laser cerclage (see below).
In bimanual surgery, the nondominant hand is used for grasping a membrane, which the surgeon then cuts with an instrument operated by his dominant hand.
Occasionally, the intraocular target area cannot be approached from the nasal side, even if this is where surgeon’s dominant hand is. Several options are possible.
The task must and can be accomplished with the nondominant hand.10
The task should but cannot be accomplished with the nondominant hand. In such cases some type of a compromise must be sought. For example, the patient has an extensive network of subretinal strands, including in the submacular area, which require removal because they do not allow retinal attachment (as clearly proven by a carefully performed air-test [see Sect. 31.1.2]). The surgeon may leave some of the subretinal membranes behind, alternate between use of the dominant and nondominant hands, use multiple retinotomies for access, or switch to a 20 g system.
Pearl
The surgeon himself may be surprised to realize how much he is able to accomplish with his nondominant hand. He should train the nondominant hand and thus improve its capability.
4.3 Mono- or Bimanual Surgery Is Preferable?
This is one of those questions to which there is no definite “this is better than that” answer.
Most (experienced) surgeons can accomplish most tasks using only one working hand.
Most surgical maneuvers can be performed using only one hand, with occasional help by the nondominant hand: the light pipe as an ancillary tool.11
Using a fixed light source12 and having two working instruments in the eye has obvious advantages but also some drawbacks.
Fixed lighting can never match the variety of illumination options the surgeon-held light pipe can provide by changing the location (switching hands), angle (shadows), and distance from the field (illumination power).
The assistant can help by changing the angle of illumination via grabbing and redirecting the permanently fixed light. However, this makes rotating the eyeball more cumbersome.
Self-illuminating instruments can eliminate or reduce the effects of these difficulties, but they introduce new ones: light reflex and additional shadow/s from the instruments themselves.
Having two working instruments in the eye requires very close coordination between the two hands.13 Such coordination is as important an issue as the dexterity of the dominant hand.
The surgeon is able to practice coordination between his two hands in many ways, outside the OR, by designing tasks that require fine bimanual movements.
A great “live” test, with only a small risk of causing significant iatrogenic damage, is “window cleaning” of the dirty anterior surface of an IOL (see Sect. 25.2.3.2).
Pearl
Whether the VR surgeon uses one or two working hands to accomplish a certain task is an individual decision, not one that should be influenced by peer pressure (see Sect. 3.9). A surgeon who is unable to have the required close coordination between the two hands should stay with the monomanual technique.
4.4 Which Gauge?14
No patient ever asks the surgeon about the gauge he used during surgery; the one thing the patient is interested in whether the operation was successful or not. Selecting the gauge (20, or MIVS: 23, 25, 27) is an individual choice: whatever the surgeon feels most comfortable with to achieve the desired outcome. The crucial difference is not related to gauge size but to whether transconjunctival or conjunctiva-dissecting (traditional 20 g) surgery is performed (see Table 21.1 for more details).
It may be advisable to mix the gauges in certain situations (see Sect. 32.4.1).
An IOFB whose every dimension exceeds the inner diameter of the cannula (see Sect. 63.7.1).
Intravitreal instruments with long blades are needed (PDR, subretinal membranes).
The smaller the gauge, the higher the flow (vacuum) required to achieve tissue attraction.
Tissue attraction means movement of the tissue toward the port.15 Conversely, at a given flow rate and at a given distance between retina and port, the risk of biting into the retina is higher with larger gauge probes.
In general, the smaller the gauge, the slower the vitreous removal.16
A probe with a smaller gauge also involves a higher chance of blockage by the aspirated material (such as lens, synchysis, hard membranes). The blockage requires flushing of the probe by the nurse or even replacement of the probe.
Sutureless, spontaneous closure of the wound (and thus the prevention of postoperative hypotony), and healing (and thus prophylaxis of wound reopening) are proportionally faster with smaller gauges.
In principle, the smaller the gauge, the less risk of causing a retinal break at the sclerotomy site, which risks the development of a postoperative RD.
I use almost exclusively 23 g because this offers most of the advantages of the 20 g instruments without significant compromise regarding functionality and the speed of the removal of vitreous, membranes, or lens material.17 Unless otherwise indicated, 23 g transconjunctival cannulas and instruments have been used throughout this book.
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