For many years I have taught and attended presentations on phacoemulsification complication management. At each course it appeared that my colleagues and I could never learn enough about this subject. However, there was repeatedly a deficiency in the method of instruction. It was often fragmented. I assumed this was brought about by the very nature of the process of dealing with complications management. The associated shock and surprise when challenged with these mishaps instigates an urgent action strategy rather than an attitude of careful analysis, then action.

I therefore decided to attempt to approach this topic with improved organization and in-depth analysis. My approach is to understand where problems may occur by first envisioning the normal circumstance. Mindful of normal procedures to avoid, then recognize, and finally manage a myriad of potential complications becomes a less overwhelming task.

To accomplish this goal I have invited a number of authors to contribute to this textbook. All are the finest educators that I have had the privilege with which to work. They are accomplished as surgeons,

researchers, and writers. All have given their knowledge altruistically, with their only goal being to improve both the quality of surgery and the likelihood for successful outcomes.

Finally, to assist us in the process of visualizing many theoretical concepts, I have enlisted the assistance of one of the most superb medical illustrators in our field. Through accurate illustrations we have attempted to refine our understanding of the many dilemmas a surgeon might encounter. As an adjunct, we have tried to formulate a more concrete method of understanding some new concepts.

This book reflects the experience of more than 3 years of research and development. It is my fervent desire that the information in this textbook has merit to the reader. If I can help to lessen the impact or improve the surgical outcome in a potentially challenging problem, I have accomplished my desired goal.

I, as well as the authors of this text, am an educator. As such, I place great importance on textbooks of this type. Please read, enjoy, and learn from the ensuing material.

William J. Fishkind, M.D., F.A.C.S.

I would like to thank the many teachers who have instructed me, polishing both my surgical and personal skills. They are mentors such as I. Howard Fine, William Maloney, Randy Olson, Alan Crandall, Manus Kraff, and C. Drew Sanders, who have placed confidence in my knowledge and supported my efforts.

I have been privileged to teach with many exceptional individuals. They are too numerous to name individually. However, all the authors of this text deserve my heartfelt thanks. They have unselfishly taken time from their busy schedules to make exceptional contributions to this text. My partner, Brock K. Bakewell deserves special recognition for his will-

ingness to critique many aspects of the text. Another thank you goes to my office administrator, Beverly Lony, and assistant administrator, Jen Engelbrecht, for helping in a myriad of subtle ways.

Finally, thanks go to Tony Pazos, the medical illustrator of this text. He spent countless hours refining illustrations in an effort to clarify abstract concepts for our collective benefit. He developed a system of overlays to improve the illustration quality. I will miss our regular meetings over the past few years.

William J. Fishkind, M.D., F.A.C.S.

xii • CONTRIBUTORS

Gimbel Eye Centre

Calgary, Alberta, Canada

Harry B. Grabow, M.D.

Clinical Assistant Professor

Department of Ophthalmology

University of South Florida

Sarasota, Florida

Jack T. Holladay, M.D., M.S.E.E.

Clinical Professor

Department of Ophthalmology

Baylor College of Medicine

Bellaire, Texas

Leonard Joffe, M.D., F.C.S.(S.A.), F.R.C.S.(Edin.)

Clinical Associate Professor

Department of Ophthalmology

University of Arizona

Tucson, Arizona

Stephen H. Johnson, M.D.

Private Practice

Newport Beach, California

Paul S. Koch, M.D.

Koch Eye Associates

Warwick, Rhode Island

Stephen S. Lane, M.D.

Clinical Professor

Department of Ophthalmology

University of Minnesota

Stillwater, Minnesota

Marc Leib, M.D., J.D.

Southern Arizona Anesthesia Services

Tucson, Arizona

Richard G. Livernois, M.D.

Medical Director

The Laser Vision Institute

Tampa, Florida

Samuel Masket, M.D.

Clinical Professor

Department of Ophthalmology

UCLA Center for Health Sciences

Los Angeles, California

Marc A. Michelson, M.D.

Assistant Clinical Professor

University of Alabama;

Private Practice

Birmingham, Alabama

Kunihiro B. Nagahara, M.D.

Santa Maria Eye Clinic

Sakaide City, Kagawa, Japan

Louis D. Nichamin, M.D.

Medical Director

Laurel Eye Clinic

Brookville, Pennsylvania

Randall J. Olson, M.D.

John A. Moran Presidential Professor

Chair and Director of the John A. Moran Eye Center Department of Ophthalmology

University of Utah Health Sciences Center Salt Lake City, Utah

Robert H. Osher, M.D.

Medical Director

Cincinnati Eye Institute;

Professor

Department of Ophthalmology

University of Cincinnati College of Medicine

Cincinnati, Ohio

Ellen E. Anderson Penno, M.D., M.S.

Gimbel Eye Centre

Calgary, Alberta, Canada

Kenneth J. Rosenthal, M.D., F.A.C.S.

Clinical Instructor

New York Medical College;

Private Practice

Kings Point, New York

Gary S. Schwartz, M.D.

Assistant Clinical Professor

Department of Ophthalmology

University of Minnesota

Stillwater, Minnesota

Barry Seibel, M.D.

Clinical Assistant Professor

University of California, Los Angeles;

Private Practice

Maloney–Seibel Vision Institute

Los Angeles, California

William E. Smiddy, M.D.

Professor

Department of Ophthalmology

University of Miami

Bascom Palmer Eye Institute

Miami, Florida

Roger F. Steinert, M.D.

Associate Clinical Professor

Department of Ophthalmology

Harvard Medical School

Ophthalmic Consultants of Boston

Boston, Massachusetts

Complications of regional anesthesia for ophthalmic surgery have become increasingly rare. This decreasing frequency can be attributed to awareness of anatomy and consequently better strategy for administering anesthetics, development of a safe and effective array of anesthetic substances, and the use of appropriate monitoring in the perioperative period. Nonetheless, while many anesthetic complications may be relatively innocuous, some may be sightor even life-threatening. As such, the administration of anesthesia should be done with proper training and experience and with care and respectful attention to detail.

GENERAL CONSIDERATIONS

In fact local anesthesia is the greatest single hazard in cataract surgery,1–4 accounting for adverse effects in 3.5% of patients (orbital adverse effects: 2.6%; systemic: 0.9%) according to a study by the Royal College of Ophthalmologists. The average cataract surgeon in the United States has a 3% chance each year of being sued over cataract surgery,5 and the majority of such cases relate to anesthetic complications such as globe perforations, inadvertent intraocular injections, and retinal detachment and intraocular hemorrhage associated with these misadventures.6

The purpose of anesthesia is to convert an otherwise painful, anxiety-producing, and unpleasant experience into a tolerable, comfortable, even pleasant and restful experience. In choosing an anesthetic technique, the least invasive, safest method, should always be employed. The extent, duration, and complexity of the surgery should therefore be evaluated in choosing

the route, duration, and depth of anesthesia employed. Exposure to anesthesia in excess of that which is necessary adds unnecessary risk to the procedure, and no tangible benefit to patient or surgical team. Regional anesthesia is usually preferable to general anesthesia, producing safer, equally effective, and cost-effi- cient results. However, just as it is inappropriate for a surgeon to use the same technique for every surgical intervention, it is equally wrong to use the same anesthetic for each case. While surgeons may subscribe to a particular philosophy of anesthesia for routine cases, it is important to assess each patient’s needs and act appropriately for exceptional cases.

DEFINITION OF INJECTIBLE BLOCK

Injectible techniques are anesthetic methods that involve the use of a sharp needle and an injectate; they include peribulbar as well as retrobulbar techniques, unless otherwise specified. The procedures collectively are referred to as “regional orbital anesthetic block.”7 It has been suggested that peribulbar block (also referred to as “periconal block”), involving injection outside of the muscle cone, entails less risk of complication than retrobulbar technique. However true this may be, complications have been observed with both techniques.8

PREOPERATIVE ASSESSMENT

Good planning is always part of the strategy to limit risk in anesthetic administration. If patients have preexisting systemic medical conditions, then some authors have felt that history, physical examination, 1

and laboratory testing should be performed.9 There is a great deal of regional and international variation in these requirements and no good standards have yet been established. A prospective multicenter clinical trial is evaluating this issue in 20,000 patients in the United States and Canada. The Study of Medical Testing for Cataract Surgery Randomized randomizes patients into either a no-routine-screening group or a routine-screening group; the latter group receives an electrocardiogram (EKG), electrolytes/ glucose, and a complete blood count (CBC). Demographic, clinical, and perioperative and medical event data is being collected through 7 days postsurgery to determine whether such testing results in differences in complications and outcomes between the two groups. A recent study by Rosenfeld et al,10 however, showed that the need for anesthesia intervention during cataract surgery was not correlated with the presence of heart disease, evidenced by an abnormal preoperative EKG, or with the presence of diabetes. EKGs and blood sugar are almost always performed during a preoperative evaluation. However, a history of systemic hypertension, pulmonary disease, renal disease, or cancer was associated with a statistically significant increase in incidence of intervention, suggesting that at least a review of the patient’s medical conditions is prudent in the immediate preoperative assessment.

Some investigators have shown that anesthetists did not make use of reported results of preoperative test and examinations, and that perioperative management was not influenced because of these investigations.11 Data from the National Survey of Local Anaesthesia for Ocular Surgery in 1997 reveals further that in patients who did not have any preoperative tests, there was a very low rate of serious adverse events that would have been influenced by such tests.12

Because cataract surgery is commonly performed on geriatric patients, a high incidence of systemic conditions such as diabetes, hypertension, coronary artery disease, obesity, chronic obstructive pulmonary disease, and arthritis may coexist and pose special challenges to the surgical and anesthesia teams. To limit the risks these conditions may generate, every effort should be made to ensure that the patient is optimally prepared for surgery. Nonetheless, cataract surgery can, in most instances, take place even in patients with these conditions.

During the immediate preoperative consultation, the patient should be asked to provide a list of current medications. In this way potential drug interactions can be anticipated, and it can be confirmed that the patient has appropriately taken the medications. It is helpful to schedule diabetic patients during the early morning, so that their oral hypoglycemics or insulin dosage can be taken immediately after the surgery. This minimally disrupts their usual routine. Alterna-

tively, they can be scheduled during the early afternoon so that they take their insulin and breakfast earlier in the day with sufficient time to fast prior to surgery.

CONSIDERATIONS REGARDING

ANTICOAGULATION

In general it is advisable to continue patients on systemic anticoagulants during routine cataract surgery, particularly in cases of small-incision phacoemulsification. Discontinuation of anticoagulant therapy may bear a greater risk than that of significant intraoperative ocular bleeding, even with retrobulbar injection.13 In these cases, however, it is of particular importance to use small needles and correct anatomic placement, and to avoid excessive manipulation while administering the injectible block. There are no studies to date, however, that have categorized the risk of cessation of anticoagulation as opposed to its continuance for many medical indications. It is recognized that stopping these medications has different implications for risk, depending on the underlying medical condition (e.g., atrial fibrillation vs. stroke vs. heart valve replacement). For example, a patient with mechanical heart valve replacement is at substantially higher risk for embolism or stroke than one with atrial fibrillation as the underlying reason for treatment. These factors should be weighed carefully, in consultation with the patient’s internist, to determine the systemic and ocular risks in each case.

THE ROLE OF THE ANESTHESIA

CAREGIVER

In the United States, both CRNAs (certified registered nurse anesthetists) and physician (MD or OD) anesthesiologists have been trained to administer anesthetics, monitor and treat a patient’s systemic condition, and provide suitable sedation. Although there are regional variations in the usage of anesthesia services both through the United States and internationally,14 the role of this vital team member cannot be overlooked. In an era where cost containment has reached a high degree of awareness, it is important to evaluate the necessity of each aspect of the care we provide. Rosenfeld et al10 showed that during cataract surgery, major anesthesia intervention (i.e., more than just verbal reassurance, hand holding, or physical restraint) was required in 28.6% of all patients. While intervention was required more often in patients with certain underlying diseases, almost a third of patients without predisposing factors required intervention of some type. This sug-

gests that with current methods it is impossible to predict preoperatively which patients will require intervention, thereby suggesting further that, to avoid perioperative complications, anesthesia monitoring is essential in all patients undergoing cataract surgery.

SEDATION AND MONITORING

Considerable debate has persisted regarding the usefulness of intravenous (IV) sedation for cataract surgery, particularly with the use of topical anesthetic agents and minimally invasive surgical technique. Although the specifics of this debate are outside the realm of this discussion, it is important to understand what constitutes appropriate use of this mode of treatment.

The anesthesiologist must possess appropriate personality traits and communication skills to enable them to gain patient trust and confidence.15 Additionally, the practitioner should educate the patient about the forthcoming experience. This helps to reduce the patient’s anxiety and decrease perioperative complications.16

Perioperative monitoring should consist, at a minimum, of EKG, pulse oximetry, and periodic blood pressure measurement.17,18 The latter should be kept to a minimum during critical surgical periods so as not to increase patient discomfort, anxiety, or movement during surgery.

The goal of IV sedation is to alleviate anxiety, while allowing the patient to remain stationary, calm, comfortable, and cooperative. In regard to the absolute amount of anesthetic agent given and the level of consciousness attained, elderly patients generally require less pharmacologic limitation of anxiety during surgery than do younger patients. It is essential to produce anxiolysis without obtundation. The latter may result in a patient who is periodically and unpredictably combative,19–22 and may cause further depression of preexisting cardiac and respiratory instabilities.23–27 In an effort to prevent this situation, excessive IV sedation should never be used to compensate for an incomplete regional anesthetic block. Rather, the incomplete regional block should be managed by supplementation of the local anesthesia. To do otherwise will subject the patient to an unpleasant, stressful, and potentially dangerous experience.15

COMPLICATIONS OF PHARMACOLOGIC

AGENTS

Systemic toxicity of anesthetic agents is usually associated with (1) inadvertent ectopic injection of an

agent, (2) overdose of a particular agent, (3) allergic reactions, or (4) vasovagal responses.

Ectopic injection may be propagated by the intravascular route or through inadvertent direct central nervous system injection through the subdural route via penetration of the optic nerve sheath.

These will each be discussed in their respective sections. However, as a general measure, limitation of these problems can be accomplished by (1) gentle preinjection aspiration to ensure an extravascular location of the needle, and (2) slow and patient injection of anesthetics15 (no more than 2 cc/min) while monitoring the patient for any signs of systemic toxicity. Finally, the use of hyaluronidase may be associated with allergic or frankly anaphylactic reactions.28 Therefore, this proteolytic drug should be avoided in atopic individuals. A study by Prosser et al29 suggests that hyaluronidase may not be necessary, at least in peribulbar blocks.

TECHNIQUE OF RETRO/PERIBULBAR

INJECTION

In preparation for the administration of the injection, the surgeon must have an awareness of the axial length of the surgical eye. A preexamination of the orbit/globe relationship should be done, and proper instruction to the patient should be given so as to avoid unnecessary movement. A history of prior difficulties with regional block in the companion eye should also be investigated and etiologic factors delineated before proceeding with the second eye.

Techniques that may reduce the likelihood of perforation have been described by numerous authors. Current practice consists of a sharp needle technique with insertion either at or slightly below the lateral canthus, or, alternatively, at the medial canthus. The needle is placed preferably though the conjunctiva rather than through the lid. The eye should be held open, remain in primary gaze, and be observed throughout the needle insertion and anesthetic injection. The eye should not move during this maneuver, as this may indicate that the sclera has been engaged. The classic concept of looking “up and in,” as popularized by Atkinson, should be absolutely avoided because it brings the optic nerve closer to the inferotemporal quadrant and places it on stretch, making it more susceptible to injury (Fig. 1–1).

There is still debate about the ideal needle for this task. Some authors, such as Waller et al, recommend using a dull needle, stating that a theoretically greater force would be required to penetrate the sclera. This argument, however, fails when one considers that any needle sharp enough to penetrate the skin will probably encounter little difficulty in penetrating the sclera. Further, because eyes at high risk for perforation often

FIGURE 1–1 Optic nerve damage. When eye is positioned “up and in,” as has been the classic teaching, the nerve is placed on stretch and positioned more inferiorly and temporally. This increases the risk of nerve damage during injection.

have scleral ectasia, there would be sufficient thinning to allow even a dull needle to penetrate. I prefer a straight, sharp, 27-gauge, short (no longer than 31 mm) bevel needle inserted as described above, with the bevel toward the globe, thus reducing the risk of damage to critical structures.

A medial orbital injection is also occasionally utilized. In this technique the needle is placed at the caruncle and injection is administered with the needle positioned with the bevel facing away from the globe so as to accommodate the sharply medioposterior sloping of the medial orbital wall (Fig. 1–2).

FIGURE 1–2 Medial block. A 27-gauge, 20to 25-mm sharp needle is placed at the caruncle with the bevel pointed away from the globe. When the needle hub reaches the plane of the iris, the anesthetic is injected near the medial orbital wall.

In retrobulbar anesthesia, the needle is inserted inferiorally, one-third the way from the lateral canthus. It is then advanced along the orbital floor. Immediately on perforating the skin or conjunctivae, the globe is actually pushed superiorally with digital pressure. Once the needle is well past the equator, it is slightly withdrawn and redirected superiorally at an approximately 15-degree angle. The needle can be felt to “pop” through the muscle cone, and the anesthetic volume is delivered with a slow and steady injection, with attention to any unusual resistance (Fig. 1–3).

With peribulbar anesthesia the needle is inserted similarly, but never redirected into the muscle cone. Instead, the anesthetic is delivered near the orbital rim. Generally it is necessary to wait a longer period of time after a peribulbar block for adequate anesthetic effect. Peribulbar injection is particularly useful superotemporally to provide sensory and motor anesthesia to the superior orbit and lid (Fig. 1–4).

PENETRATION AND PERFORATION

OF THE GLOBE

The administration of regional orbital anesthetic block is a technique requiring specific training and experience. In some institutions the block is given by the least experienced surgeon or by anesthesia personnel who often have inadequate experience or training. This practice is to be discouraged. A detailed study of the orbit, its nerves, vasculature, and soft tissue septa should be undertaken prior to undertaking injectible anesthesia. Regional orbital anesthesia requires an anatomic appreciation in three dimensions. To ensure success, hands-on, one-to-one training is required.

Globe penetration is the most common of the serious complications of injectible anesthesia and has been documented by numerous authors.30–33 Globe perforation and inadvertent intraocular injections also rank as two of the most common causes of litigation after cataract surgery.6 Ocular penetration refers to the entry of a needle into the globe after which the needle is withdrawn. Ocular perforation suggests that the needle entered the eye and then exited through another part of the globe prior to having been withdrawn. Because the clinical pictures are similar, the terms are used interchangeably in this discussion.

The actual incidence of ocular penetration is difficult to determine. This is due to a tremendous diversity of reports that have appeared in the literature. Reported incidences range from as few as one penetration in 16,224 consecutive cases,34,35 to as many as 1 in 100 cases. Teichmann and Uthoff36 reported an incidence of 0 in 21,000 using their technique. If the incidences reported in several available references

are averaged, the occurrence rate is approximately 0.01%.

Because the risk of this complication is directly related to the number of injections given, every effort should be made to reduce the frequency of multiple injections. Correct needle placement, use of hyaluronidase, and adequate volume of injectate will increase the likelihood of success of a “first take.” Ocular compression devices such as the “superpinky” or the Honan’s37–39 balloon may likewise improve the

distribution of anesthetic. They must be used judiciously to avoid both vascular compromise to the globe and the creation of an excessively soft eye. A good end point for determination of adequate block should be the ablation of sensation to the area to be operated upon. Testing by lightly pinching the conjunctiva with a 0.12 Castroviejo forceps will give adequate indication of anesthesia. It is not necessary to achieve akinesia or amaurosis. Insistence on achieving these end points may result in the necessity of