PREVENTION PEARLS AND
DAMAGE CONTROL: PART 3

Louis D. Nichamin

This chapter describes my current technique used to perform “routine” temporal clear corneal phaco surgery. The focus is on subtle points of the procedure that help to make the procedure easier, avoid trouble, and in general lead to the most reproducible outcomes. I then review the common difficult situations faced by today’s phaco surgeon, and discuss the principles and pearls that can make dealing with these trying situations easier.

ROUTINE CLEAR CORNEAL PHACO SURGERY

If you have ever had the opportunity to observe a true master of phacoemulsification perform surgery, you likely have wondered, as I have, why it is that they can consistently achieve flawless results with aplomb and ease. The answer, of course, is to be found in their attention to detail. In the following discussion, the procedure itself, will be broken down into its basic components, and those details that I have come to rely upon to keep me out of trouble will be emphasized.

TOPICAL ANESTHESIA

The advantages of noninjection anesthesia to both patient and surgeon are numerous. A common denominator for success, for both the novice as well as experienced surgeon, is proper patient selection. In fact, after approximately four years of performing topical (and later intracameral) anesthesia, my percentage of noninjection cases began to approach the 98% level. I realized that my surgery had become less enjoyable. This was due to “pushing the envelope.” I was in reality operating on some patients who were not appropriate candidates. In recognition, I now approximate a 90% topical frequency. This has greatly improved the efficiency and enjoyment of my surgery. The point is that patient selection is the key! It’s basically no fun chasing after a roaming eye or fighting nearly constant blepharospasm. With experience, the selection criteria can be refined into a simple form to accurately predict how well a given patient will tolerate noninjection anesthesia. My assessment is based on several simple and routine elements of the preliminary exam and how the patient reacts to them.

NONINJECTION ANESTHESIA—SELECTION CRITERIA

If the patient exhibits unusual blepharospasm or a marked Bell’s phenomenon during biomicroscopy and, in particular, indirect ophthalmoscopy, the patient is almost always deemed an inappropriate candidate for topical anesthesia. I further empower my surgical assistants who perform our biometric measurements to designate on the chart that the patient exhibited poor cooperation, and I adhere to their recommendations.

ANESTHETIC TIMING AND AGENT

The next important point is that it actually takes very little topical anesthesia to adequately anesthetize the eye for intraocular surgery. I have found that nearly any common topical anesthetic will do, but the important point is not to overdo it. Administering two to three drops of any topical agent just prior to performing the surgical prep, only a minute or two before actually beginning surgery, is best. If instilled too early, despite insisting that patients keep their eyes closed, they will still gaze about the room curious about the unfamiliar situation and surroundings. Excessive drying of the epithelium will undoubtedly ensue. This may potentially compromise intraoperative visualization as well as increase postoperative discomfort.

PATIENT SENSATION

Another important clinical point is that the sensation that is most profound to the patient while under topical anesthesia involves stretching of the zonular apparatus. This is most likely to occur in high myopes and in patients who have had previous vitreous surgery. I find that topical anesthesia may still be used in these cases, but great care must be taken to gradually deepen the anterior chamber, trying to avoid a sudden and severe stretch placed upon the zonules. Even in routine cases, patients may note some sensation when the irrigation and aspiration (I&A) is first placed into the eye following phacoemulsification. It is at this point during the procedure that the greatest hydrostatic tension is placed upon the zonules. Therefore, I find it helpful to instill additional intracameral anesthesia during the exchange of the phaco to I&A instrumentation. The increase in anterior chamber volume due to the additional anesthetic and BSS will also help to blunt the sudden pressure and volume rise that occurs upon reentering the eye.

The surgeon should be aware of an interesting phenomenon that occurs in an eye that has previously undergone vitrectomy surgery. Shortly after adopting noninjection anesthesia, I had the surprise to learn that in the postvitrectomized state, intracameral anesthesia can very efficiently diffuse to the retina and cause amaurosis despite an intact posterior capsule. Similarly, if a capsular rent occurs intraoperatively, particularly if a vitrectomy is required, diffusion may again occur. Patients should be warned of a temporary diminution or loss of their vision. To my knowledge, no untoward sequelae have ever been documented following this phenomenon. In fact, I have personally employed topical and intracameral anesthesia in planned posterior vitrectomy cases.

EXPOSURE AND INSTRUMENTATION

It is well recognized that one of the greatest advantages of the temporal approach is better access to the globe and improved exposure and intraoperative visualization. In fact, once surgeons have accomplished this somewhat challenging transposition, they will likely find that they abhor the superior approach. In transitioning to a temporal approach, several challenges arise: positioning one’s knees under the operating table, acquiring adequate wrist support, and shifting personnel and equipment into a new workable configuration. Once these major hurdles are met, several additional subtle challenges are recognized. One of these is that access to the side-port incision, which is now either at the 6 or 12 o’clock position, may be difficult. In addition previous instrumentation design for a superior approach may no longer be optimal for temporal surgery.

A number of specialized speculae have been designed for the temporal approach. One, a modification to the classic Kratz-Barraquer wire lid speculum, works well in most patients. This is made of a heavier gauge metal making it more resistant to blepharospasm. In addition, the temporal aspect is angulated posteriorly, over the lateral canthus, such that it is out of the way of incoming instrumentation. I also use a similar design with a locking mechanism for those patients who are truly squeezers; however, if I have adhered to the preoperative selection criteria, this situation rarely arises because the squeezing patient should have been scheduled to receive injection anesthesia.

One challenging new peculiarity of the temporal approach is access to the side-port incision. When operating superiorly there was unlimited access to the paracentesis. Now, however, access to the 6 or 12 o’clock position may be hampered by either the lid speculum or the orbital rim, particularly in deep-set eyes or in individuals with narrow palpebral fissures. For this reason, additional modifications to conventional instrumentation may be of help. These include nuclear manipulators that have a more vertical angulation to better fit down into a deep-set eye. Also, modified irrigating cannulae with shortened tips will facilitate placement through side-port incisions.

Always important is the detail of patient positioning. One must ensure that the patient’s neck is neither hyper- nor hypoextended. My operating room personnel labor over this detail (after years of my urging them to do so!). I further employ a subtle but helpful maneuver taught to me by Bruce Wallace (Alexandria, LA). By slightly tilting the head toward the side that the surgeon is sitting on, there is significant improvement of visualization as well as the ergonomic positioning of the microscope. There is a tendency during surgery for the patient to move away from the surgeon, so we routinely place a very light strip of tape over the patient’s forehead as a friendly reminder to maintain the position.

Lastly, to improve efficiency and logistics in the operating room, all right eyes are scheduled together as are the left eyes, to avoid having to make unnecessary changes to the positioning of the equipment and instrumentation.

INCISION

One certainly does not need to extol the many virtues of clear corneal incisions, as they have now been elaborated upon extensively. A simple point, however, should be stressed: proper sizing of an incision (to the phaco needle and sleeve combination that is used) is of paramount importance to achieve optimal fluidics. Too tight an incision risks a corneoscleral burn, but the more common tendency is to use an incision size that is slightly too large and therefore may lead to unnecessary leakage. When working through an unobstructed single plane temporal clear corneal incision, I find that a 2.8-mm incision works best with most standard diameter phaco tips. A 2.5-mm incision is typically used with the “micro” tips. A grooved incision tends to gape more and will therefore behave as if it were a slightly larger incision.

Equally important, keep in mind that most side-port manipulators will pass through an incision of 0.5 to 0.7 mm, thus making the standard 1-mm side-port incision far too large and, hence, leaky.

CAPSULORRHEXIS

The key to performing a good, consistent capsulorrhexis is maintenance of a deep anterior chamber. For this reason, my personal preference is to use a cystotome needle that is attached directly to a viscoelastic cannula. In this way, the anterior chamber can be immediately redeepened if shallowing occurs or if extension of the tear is imminent.

My standard capsulorrhexis technique begins centrally with a circumlinear puncture creating a flap that is then folded over upon itself and advanced with the needle utilizing a shearing rather than a tearing force. Generally, one or two additional injections of viscoelastic are used during completion of the tear. Previously torn and bunched up capsule is pushed centrally, clearing the way for the leading edge of the tear. The torn segment of capsule is also removed from the anterior chamber. This ensures that the tear has been completed 360 degrees. If this is not done, sooner or later, after entering the eye with infusion, the incomplete capsular tear will inevitably progress to the equator with the introduction of the phaco handpiece. Additionally, when removing the torn capsule, gentle pressure on the posterior lip of the incision allows decompression of the anterior chamber. This makes the next step of the procedure, hydrodissection, safer.

HYDROSTEPS

Thorough hydrodissection is of great importance to ensure trouble-free phacoemulsification. In fact, inadequate hydrodissection may often be traced back as being the cause of a subsequent complication. Adequate hydrodissection should be confirmed by visualizing free and easy rotation of the lens within the capsular bag. I personally continue to revel in the efficiency of cortical cleaving hydrodissection as taught by Howard Fine (Eugene, OR). Without irrigation I place a flattened hydrodissection tip under the anterior capsular leaflet and inject gently. Two separate irrigation points 180 degrees apart ensure adequate hydrodissection. Each time, the lens is balloted in a posterior direction, causing the injected fluid to pass up and around the equatorial region, lysing cortical capsular adhesions.

PHACOEMULSIFICATION

Variations on the original Nagahara phaco chop technique abound today. My personal preference is for a subtle but important variation on the traditional chop technique called “quick chop,” a term coined by David Dillman (Danville, IL). This technique, with slight variations, was described contemporaneously by several surgeons, including Thomas Neuhann (Germany), Vladimir Pfeifer (Slovenia), Abhay Vasavada (India), and Hideharu Fukasaku (Japan). Several key points pertain to all phaco chop techniques.

First, one should get in the habit of exposing more of the phaco needle (beyond the leading edge of the silicone sleeve) to allow for a deeper purchase of the nucleus. I personally find that a 15- to 30-degree bevel tip is optimal. Although 0-degree tips may occlude better, a small bevel can be used to help manipulate nuclear fragments. After chopping, it is best to try to tip up cleaved segments for purchase rather than allow them to tumble forward. This may be facilitated by using the manipulator to push the chopped segment out toward the equator of the bag, which in turn causes the posterior apical aspect to slide upward.