THE ROTO-EXTRACTOR IN PEDIATRIC OPHTHALMOLOGY* BY Joseph
H. Calhoun,
MD (BY INVITATION) AND
R. D. Harley, MD SINCE THE INTRODUCTION
OF DISCISSION-ASPIRATION FOR
REMOVING CONGENITAL
cataracts, there have been many modification of this technique. Over the past several years ingenious instrumentation has been developed that provides the surgeon an even wider choice of techniques. 1,2,3,4'5 The purpose of this paper is to relate our experience with one of these newer instruments in the treatment of cataracts in the young patient. Although a long term follow-up is not available, it is important to review our experience to this point. In September 1972, Doctor Nicholas Douvas of Port Huron, Michigan, presented at the American Academy Meeting in Dallas, a preliminary report of the Roto-Extractor that he had developed.4 This instrument was further modified to its present form and released for sale late in 1973. In the spring of 1974, the Pediatric Ophthalmology departments of Saint Christopher's Hospital for Children and Wills Eye Hospital in Philadelphia obtained one ofthese instruments. Our experience with this instrument in surgery of the lens in children will form the basis of this report. The Roto-Extractor is a miniaturized instrument for removing intraocular contents. Its most important component is the cutting tip which is placed into the eye (Figure 1). Like the phaco-emulsifier, the tip incorporates an infusion and an aspirating system, but, unlike the phacoemulsifier, the Roto-Extractor cuts the intraocular material into small pieces by the action of the cutter blade. The tip consists of three concentric tubes, the diameter of the outermost is 1.4 mm. The proximal part of the tip is incorporated into the handpiece. Between the outer and middle tube runs the infusion fluid, plain Ringers solution, to main*From the Department of Pediatric Ophthalmology, Wills Eye Hospital and Saint Christopher's Hospital for Children, Philadelphia, Pennsylvania. This study was supported in part by grants from: Fight for Sight, Incorporated, New York. Pennsylvania Lions Eye Conservation Fund. TR. AM. OPHTH. SOC., Vol. LXXIII, 1975
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FIGURE 1
Schematic diagram of the three tubed, side cutting tip of the roto-extractor. One of the infusion ports (the other is on the opposite side of the tip) is indicated by the large curved arrow. The aspirating port is shown by the arrow on the top of the tip. The innermost tube is partially cut away to form a blade. Intraocular material enters by suction through the aspiration port, is cut by the rotating blade, and further aspirated out of the eye as shown by the arrow on the right. (Through the courtesy of Nicholas G. Douvas, M.D.).
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tain the anterior chamber and the intraocular pressure. The fluid is gravity fed from an I.V. bottle into the handpiece and then through the tip, into the eyes. Aspiration or suction is controlled by the surgical assistant using a syringe. The aspirated material enters the innermost tube of the tip through a small hole, either 0.4 or 0.6 mm, in the side of the middle tube, just back from the distal end. Unlike the Vitreous Infusion Suction Cutter (VISC)2 the Roto-Extractor is a side cutting instrument. The distal end of the innermost tube has about 3/4 of its circumference cut away. What remains is sharpened on each side to a knife like edge. This distal portion, the cutting part, presses against the aspiration port in the middle tube. The innermost tube, the cutting blade, can be either rotated or oscillated by a motor in the handpiece. This action is under the direct control of the surgeon using a foot-pedal acting through a console. Intraocular material that is aspirated into the small port on the side of the middle tube is immediately cut by the action of the rotating cutter and further aspirated through the handpiece into the assistant's syringe (Figure 2). The Roto-Extractor in effect chews intraocular contents into tiny pieces so that they may then be aspirated into the tip and then out of the eye. The Roto-Extractor will chew up or fragment secondary membranes, iris, vitreous, and some cataracts.
FIGURE 2
Schematic diagram of handpiece and tip showing inflow and outflow paths. (Through the courtesy of Nicholas G. Douvas, M.D.).
295
Roto-Extractor TABLE I: CASE NIATERIAL
Total eyes Cataracts
Secondary membranes Congenital Traumatic
Acquired
66 47 19 35 23 8
Our experience has been limited by the nature of our practice largely to anterior segment problems in children and some traumatic cataracts in young adults. We have had no experience with the typical adult cataract of nuclear sclerosis. The basis for this report is 66 eyes in 57 patients (Table I). The age range was 7 weeks to 46 years. Thirty-five of the eyes had congenital cataracts or secondary membranes from congenital cataracts by other procedures; 23 were secondary to trauma; while the remaining 8 eyes developed cataracts of a non-traumatic manner. The average age at the time of surgery for those patients with congenital cataracts was 2.4 years; 9 of these patients were under 6 months of age. The average age for the patients with traumatic cataracts or traumatic secondary membranes was 16.4 years with a range from 5 months to 46 years. The surgical technique is basically simple. The first step is to assemble the Roto-Extractor from its sterile case. This includes placing the motor in the handpiece, attaching the two lines of tubing for the infusion and the suction, attaching the tip, and flushing the system free of air. This requires about five minutes and its performed by the surgeon, his assistant, or an operating room nurse. Using the operating microscope and under general anesthesia, a small limbus based flap is then made either superiorly or superior temporally. This is carried down to the limbus. A Graefe knife ofabout 2.4 mm width is then used to make an incision ofjust this size about 1 mm posterior to the limbus. The tip of this knife then enters the lens at the pupillary border adjacent to the sclerostomy. The tip of the RotoExtractor is then placed into the eye and enters the lens at the opening created by the Graefe knife. As the eye is entered the infusion fluid in the I.V. bottle is started so as to deepen the anterior chamber and raise the intraocular pressure. The cutting port on the tip is directed to the material to be removed, suction is applied by the assistant by means of the syringe, and the cutter blade is activated by the surgeon using the foot pedal. This sequence of positioning the tip, application of suction and activation of the cutter is continued until the pupillary aperture is clear. This sequence of events takes place in the posterior chamber. The nucleus of the lens does not have to be dislocated into the anterior
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chamber. Usually the anterior capsule and cortex of the lens are removed first. Removing the posterior capsule is usually performed near the end of the procedure when a better view of this structure can be obtained. This visualization is aided by coaxial illumination. Included in the removal of the posterior capsule is a portion of the anterior vitreous in nearly all cases. The follow-up, by one or the other authors, has ranged from one day to 10 months with an average of 52.9 days. RESULTS
In general, the results have been excellent. Results in this type of surgery are difficult to quantitate. In children with congenital cataracts, youth and amblyopia make vision an unreliable indicator of surgical success. In many of the traumatic cases associated injury to the cornea or retina precluded meaningful visual results. For a successful result we, therefore, chose as our criterion a pupillary aperture that was optically clear nearly to the edge of the iris. This clear pupillary space was achieved in 63 of 66 eyes. One failure was due to poor technique. The remaining secondary membrane was easily removed at a subsequent procedure. Another failure was caused by a thick secondary membrane. In this eye about one half of the secondary membrane remained after surgery. It could not be cut with the Roto-Extractor. The clear portion was large enough to allow the patient to see 20/30 through the open portion. A third case called a failure was a child with persistent hyperplastic primary vitreous (PHPV). Not all of the retrolental membrane could be removed, but the cataract came out easily. However, this is not to say that the ocular results were excellent in 63 of 66 eyes. In four of the traumatic cases the eyes have either undergone enucleation (one eye) or are in varying stages in the evolution of phthisis (3 eyes). In each of these eyes the traumatic cataract was easily removed from the pupillary aperture but persistent and severe inflammation led to the formation of cyclitic membranes and hypotony. In each case the original trauma was severe and the referring physician and the patient understood the desperate nature of the ocular condition. COMPLICATIONS
The complications have been few compared to the complications of other surgical techniques for doing similar procedure (See Table II). None of the eyes had corneal damage, other than transient edema at
297
Roto-Extractor TABLE II: COMPLICATIONS
Inadequate opening Vitreous to wound Corneal damage Vitreous hemorrhage Hyphema Unplanned iridectomies Prolonged inflammation
3/66 0/66 0/66 3/66 3/66 9/66 9/66
the incision site. This was infrequent and cleared in all eyes in a day or two. None of the eyes have developed retinal detachment. Three of the eyes had scattered blood in the vitreous. This cleared within several weeks without untoward sequelae. Hemorrhage into the anterior chamber has been a minor problem. This has occurred in 3 patients, one of which was the previously mentioned patient with PHPV. In the other 2 patients the hyphema was small and cleared in several days. There are two complications that seem unique to this type of procedure. The first is unplanned iridectomies or sphincterectormies (Figure 3). For the basis of this report this was defined as a surgical defect in the pupillary margin that is grossly visible and that was unplanned.
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FIGURE 3
Unplanned iridectomy. Note the semicircular defect in the pupillary border at 6:00 o'clock position, two days postoperative.
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This occurred in 9 of the 66 eyes. Prolonged inflammation, longer than one week, that could not be accounted for by either the preoperative or postoperative appearance of the eye, occurred in nine eyes also. This was characterized by persistent pain, photophobia, ciliary injection, and anterior chamber and vitreous reaction that responded poorly to topical atropine and steroids. DISCUSSION
The Roto-Extractor will mechanically fragment and aspirate with relative ease iris, vitreous, nearly all types of secondary membranes or after cataracts, traumatic cataracts, and cataracts that occur in children. Since surgical techniques are available that adequately remove many congenital and traumatic cataracts, the value of the Roto-Extractor does not stand out as clearly in these cases. The Roto-Extractor does have the advantage in these cataracts in that in one procedure, the entire cataract can be removed to the edge of the pupil. There is no need for additional procedures for preliminary ripening or softening and later for discission of a secondary membrane. In removing the posterior capsule with the Roto-Extractor, however, a portion of the anterior vitreous is removed also. This is accomplished by the cutting action of the rotating blade so. that there is no traction on the vitreous. Although vitreous is removed or lost by this procedure, none is left in the wound. Current understanding of the mechanism of the adverse effects of vitreous loss in conventional anterior segment surgery is that vitreous incarceration in the wound acts as a traction band to the vitreous attachment to the retina. Postoperatively most of these patients show, by the slit lamp, a paucity to absence of the anterior vitreous in the portion of the posterior segment just posterior to the iris. In several weeks, the vitreous apparently comes forward so that this portion assumes a more normal appearance, but rarely does a vitreous face form. The vitreous has not produced a pupillary block or come forward into the anterior chamber. There have been no apparent ill effects on the retina from this procedure in our series but the longest follow-up is 10 months. Although there is a reluctance by ophthalmic surgeons to remove vitreous electively, there seems to be an increasing realization that if a partial vitrectomy is performed with reasonable care, the eye tolerates the reduced vitreous volume reasonably well.6.7 It is in the cases that are difficult by conventional techniques where the advantages of the Roto-Extractor are more apparent. In cases with dense secondary membranes; lens, vitreous, or iris to a corneal wound;
Roto-Extractor
299
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Dense secondary membrane immediately preoperative (A) and postoperative (B).
300
Calhoun and Harley
or bound down or up drawn pupils, the unwanted tissue is relatively easy to remove (Figure 4). Usually an edge or opening into the secondary membrane has to be created either with a knife needle or a sclerotome. The cutting action of the Roto-Extractor works best when there is an edge of tissue to aspirate into the port on the middle tube of the tip so that the cutter blade can fragment or cut the tissue into smaller pieces to be further aspirated. In cases in which the pupil is up drawn or bound down by synechiae, the cutting action of the Roto-Extractor can enlarge the pupil to any desired size. Small pupils, as in cases with cataracts secondary to chronic uveitis, are not a contraindication as with the phaco-emulsifier. In this type of case the opening into the lens or lens material should be made not at the edge of the small pupil, but through the iris at the point of the desired diameter of the eventual pupillary opening. Three cases of PHPV have been operated upon by the authors. Two of the cases were advanced with secondary cataract, shallow chamber, and secondary glaucoma. The third case, done at 8 weeks of age, had only a retrolental membrane with a clear lens. In each case the approach was through the pars plana instead of at the limbus. In each case the lens was removed easily and the membrane with some difficulty in the two advanced cases. This type of case could probably be done also by a limbal approach with the option of closing that wound and converting to a pars plana approach if the need should arise. The anterior chamber is constantly maintained by the gravity fed infusion system. This is from two bottles at different heights connected to the handpiece by a T tube. The low bottle is normally placed about 20 inches above the level of the eye. It is constantly open to maintain a steady level of intraocular pressure. If fluid is leaking around the incision and the chamber is shallowing, the bottle can be raised to compensate for this with an increased flow rate. The higher bottle can be opened by the surgeon with the foot pedal. It is usually activated when active cutting and aspiration are taking place. Because the anterior chamber is constantly maintained is no doubt one of the reasons why we have not seen any corneal edema following this procedure. The youth of the patients and the integrity of the corneal endothelium in this age group also play an important role. Only five of the patients, all with traumatic cataracts, were over 20; the oldest 46. Other investigators will likely comment in the future on the effects of this procedure on the cornea in older patients. Hemorrhage during the procedure is uncommon and easily managed. The infusion pressure can be raised by adjusting the height of the infusion
Roto-Extractor
301
bottle till the hemorrhage is controlled. The blood can then be aspirated out of the eye. If the anterior vitreous is removed during the surgery this is automatically replaced by the infusion fluid. At the conclusion of the procedure as the tip is removed, the fluid leaks out of the wound creating a hypotonic eye. Intraocular hemorrhage that was controlled during surgery by the infusion fluid could recur at this point, but this has happened in only a few cases and to a small degree. Because the anterior face of the vitreous is broken, what blood there is in the anterior chamber seems to diffuse back into the vitreous where it may remain scattered or in clumps. This hemorrhage that falls back into the vitreous has in all cases gradually absorbed over several weeks. The Roto-Extractor easily removes iris tissue. For this reason it is well suited to create or enlarge a pupillary opening. Sometimes during the course of the procedure some of the iris tissue at the pupil inadvertently is pulled into the aspirating port. Most of the time this tissue can be pushed out of the port by reversing the action of the syringe and creating positive pressure in, what is normally a negative pressure system, the innermost tube in the tip. In those situations where the iris cannot be freed, it must be cut. This creates a semicircular defect about 1 mm in
FIGURE 5
Comfortable eye one day following surgery in child with bilateral cataracts.
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Calhoun and Harley
FIGURE 6
Preoperative (A) and two days postoperative (B) in 5 month old child.
diameter in the pupillary border. This occurs most often as the surgeon is zealously attempting to remove all lens material next to or under the pupillary edge and the assistant creates too much suction pressure with the syringe. This complication occurred nine times in this series. Usually the eyes are white, pain free, and can be refracted or examined with the indirect ophthalmoscope the day after surgery (Figures 5, 6). But in some cases (9 of 63 eyes in this series) severe postoperative inflammation was significant.
Roto-Extractor
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The problem of persistent inflammation in the face of otherwise uncomplicated surgery is more baffling. The clinical picture is, in addition to the patient's complaints of photophobia and pain, a relatively white eye except for ciliary flush, with flare in the anterior chamber, and a slightly hazy vitreous. In all cases the eye was quiet preoperatively, occurring 8 of 9 times in eyes with congenital cataracts or secondary membranes from congenital cataract surgery. It is not related to visible persistent lens material since in each of these cases, the lens was nearly totally removed. The clinical pictures resemble to some degree the sterile inflammation seen after intracapsular extractions in adults.8 It does not seem to be related to iris trauma or inadvertent iridectomies. Perhaps the trauma of the current of the infusion fluids within the eye might create an iritis but this phenomenon is not related to the length of time the tip is in the eye. One explanation is that some foreign material might be introduced into the eye, either from the components of the Roto-Extractor, through improper cleaning, or during sterilization. The most attractive hypothesis is that fragments of lens material fell back into the vitreous. This could occur if the posterior capsule and anterior vitreous face are ruptured early in the process of removing the lens. Because of the presence of the infusion fluid, vitreous would not come forward but fragments ofthe lens that for the moment escaped from the suction current could easily fall back into the vitreous through the defect in the anterior hyaloid face and create a phacolytic uveitis. It is in these patients that photophobia precludes an adequate examination of their vitreous to look for lens fragments. None have been subjected to an examination under general anesthesia to circumvent the photophobia to further elucidate the mechanism. In two of the 9 eyes with prolonged inflammation the surgery was for secondary membranes. In these two cases it is unlikely that there was enough lens cortex present to create a phacolytic uveitis. Perhaps there are several mechanisms for this complication. Other than the discomfort to the patient there seems to be no ill effects from this inflammation. SUMMARY
The Roto-Extractor, designed by Nicholas Douvas, M.D., was used by the authors in 66 eyes for cataracts, secondary membranes, and persistent hyperplastic primary vitreous. The average age of the patients with congenital cataracts was 2.4 years, for traumatic cataracts 16.4 years. The pupil was cleared well in 63 of these eyes. There was no vitreous to the wound in any of the eyes. Unplanned iridectomies and prolonged inflammation were the major complications.
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Calhoun and Harley REFERENCES
1. Kelman CD: Phaco-emulsification and aspiration. A new technique of cataract removal. A preliminary report. Am J Ophthalmol 64:23, 1967. 2. Machemer R, Parel J, Buettner H: A new concept for vitreous surgery. 1. Instrumentation. Am J Ophthalmol 73:1, 1972. 3. Shock JP: Phacofragmentation and irrigation of cataracts. A preliminary report. Am J Ophthalmol 74:187, 1972. 4. Douvas NG: The catarct roto-extractor (a preliminary report). Trans Am Acad Ophthalmol Otolaryngol 77:792, 1973. 5. Girard LJ, Hawkins RS: Cataract extraction by ultrasonic aspiration. Vitrectomy by ultrasonic aspiration. Trans Am Acad Ophthalmol Otolaryngol 78:50, 1974. 6. Cerasoli JR, Kasner D: A follow-up study of vitreous loss during cataract surgery managed by anterior vitrectomy. Am J Ophthalmol 71:1040, 1971. 7. Machemer R, Norton EWD: A new concept for vitreous surgery. 3. Indications and results. Am J Ophthalmol 74:1034, 1972. 8. Hogan MJ: Postoperative Iridocyclitis, in symposium: Postoperative cataract complications. Trans Am Acad Ophthalmol Otolaryngol 61:33, 1957.
DISCUSSION
DR P. ROBB MCDONALD. The authors have reported on a fairly extensive series accumulated within a period of one year. There is no question that an era of instrumentation is upon us. Dr Calhoun has discussed the mechanics of the roto-extractor, though I have not used it I have seen it in use. There are now several other instruments of somewhat similar construction. Two that I know of have the cutting orifice on the side and one at the tip. The suction of digested material is controlled by the operator on the handle of the instrument or by an assistant. The SITE instrument (Suction Infusion Tissue Extractor) developed in Philadelphia, has a rotatory cutter on the side of the tip of the instrument as does the roto-extractor and the suction can be graduated by the surgeon. Should the blades become dull it may wind up tissue like spaghetti, by reversing the cutting blade it may unwind. There are other instruments that have been developed in which the cutting blade is at the tip and acts as a guillotine; with this, one avoids the rotatory action which may tear tissue into the rotating blade. Undoubtedly we are on the threshold of many new refinements. Most of the instruments have been developed primarily for vitreous surgery, but because of their cutting action, can also be used for anterior segment surgery, i. e., secondary membranes, traumatic cataracts, etc. My own experience is very limited. I have used it only for secondary membranes resistant to more conventional methods of approach. The results in these few cases were satisfactory except for one of a rather severe postoperative uveitis, which responded in ten days to appropriate therapy. David Shoch many years ago stated "vitreous is a sticky, slimy substance which most surgeons try to avoid." This statement I think still hold true for the conventional cataract operation, though should vitreous be lost, an anterior vitrectomy at the time of surgery has certainly reduced the incidence of those updrawn pupils, red eyes and discomfort in those patients whom we wish we had never seen.
Roto-Extractor
305
With these instruments one seldom if ever sees vitreous in the wound of entrance, but I cannot help but wonder what the final outcome of an anterior vitrectomy will be in an infant. In time this might result in traction bands resulting in a retinal detachment. A well performed discission and aspiration of a congenital cataract leaves a minimal posterior capsule with few Elschnig pearls. A small discission of the posterior capsule may be performed if necessary without disturbing the vitreous. There is no question that instrumentation has widened our horizons in ophthalmic surgery and I thank the authors for permitting me to see their manuscript and congratulate them on their results. DR R. D. HARLEY. Mr President. Mr Secretary. We wish to thank Dr P. Robb McDonald for his interesting discussion. Surgery for congenital cataract has undergone many variations in an effort to reduce risk and improve visual results. Our present day method of discission and aspiration through a small needle-sized opening as described by Scheie is a considerable improvement over earlier methods of linear extraction and multiple discissions. Long-term results with significant reduction of late complications have been most apparent. Recently, a group of new modalities utilizing ingenious instruments have been introduced which will require evaluation in terms of immediate and long-term results. Our experience with the Douvas Roto-Extractor would suggest that it offers no great advantage for the removal of the routine congenital cataract. However, it does seem to have a special advantage in certain conditions such as dense secondary membranes, irido-capsular adhesions to corneal scars, certain cases of persistent hyperplastic primary vitreous, dislocated lens, and severe hyphema. The chief advantages of the Roto-Extractor are that surgery can be performed through a small opening, it leaves a clear, black pupillary space with Ino posterior capsule; it is probably less traumatic in complicated cases with dense memiibranes, adhesions or updrawn pupils and it permits earlx ambulation. The chief disadvantages are unplanned sphincterectomnies or iri(lectomies, prolonged inflammation in certain cases, and loss of the anterior vitreouis. Final assessment of results will require time as to its ultimate usefuilness in ophthalmology. Our present viewpoint is that our residenits should become famililiar with the discission-aspiration technique as the primary procedure. For the special problems involving congenital cataracts, the Roto-Extractor and similar instruments vill have a useful purpose. An instrument similar to the Roto-Extractor has beenI developed in the Philadelphia area. It is known as the SITE instrumenit (Suctioni Infusion Tissuie Extractor). A short imlovie illustratinig the use of this instrument wvill be shown. Similar instruments are available and eventuallv the exact indicationis for such proce(dures will be defined.
H. Calhoun,
MD (BY INVITATION) AND
R. D. Harley, MD SINCE THE INTRODUCTION
OF DISCISSION-ASPIRATION FOR
REMOVING CONGENITAL
cataracts, there have been many modification of this technique. Over the past several years ingenious instrumentation has been developed that provides the surgeon an even wider choice of techniques. 1,2,3,4'5 The purpose of this paper is to relate our experience with one of these newer instruments in the treatment of cataracts in the young patient. Although a long term follow-up is not available, it is important to review our experience to this point. In September 1972, Doctor Nicholas Douvas of Port Huron, Michigan, presented at the American Academy Meeting in Dallas, a preliminary report of the Roto-Extractor that he had developed.4 This instrument was further modified to its present form and released for sale late in 1973. In the spring of 1974, the Pediatric Ophthalmology departments of Saint Christopher's Hospital for Children and Wills Eye Hospital in Philadelphia obtained one ofthese instruments. Our experience with this instrument in surgery of the lens in children will form the basis of this report. The Roto-Extractor is a miniaturized instrument for removing intraocular contents. Its most important component is the cutting tip which is placed into the eye (Figure 1). Like the phaco-emulsifier, the tip incorporates an infusion and an aspirating system, but, unlike the phacoemulsifier, the Roto-Extractor cuts the intraocular material into small pieces by the action of the cutter blade. The tip consists of three concentric tubes, the diameter of the outermost is 1.4 mm. The proximal part of the tip is incorporated into the handpiece. Between the outer and middle tube runs the infusion fluid, plain Ringers solution, to main*From the Department of Pediatric Ophthalmology, Wills Eye Hospital and Saint Christopher's Hospital for Children, Philadelphia, Pennsylvania. This study was supported in part by grants from: Fight for Sight, Incorporated, New York. Pennsylvania Lions Eye Conservation Fund. TR. AM. OPHTH. SOC., Vol. LXXIII, 1975
I-.
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f
I.
L_
FIGURE 1
Schematic diagram of the three tubed, side cutting tip of the roto-extractor. One of the infusion ports (the other is on the opposite side of the tip) is indicated by the large curved arrow. The aspirating port is shown by the arrow on the top of the tip. The innermost tube is partially cut away to form a blade. Intraocular material enters by suction through the aspiration port, is cut by the rotating blade, and further aspirated out of the eye as shown by the arrow on the right. (Through the courtesy of Nicholas G. Douvas, M.D.).
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Calhoun and Harley
tain the anterior chamber and the intraocular pressure. The fluid is gravity fed from an I.V. bottle into the handpiece and then through the tip, into the eyes. Aspiration or suction is controlled by the surgical assistant using a syringe. The aspirated material enters the innermost tube of the tip through a small hole, either 0.4 or 0.6 mm, in the side of the middle tube, just back from the distal end. Unlike the Vitreous Infusion Suction Cutter (VISC)2 the Roto-Extractor is a side cutting instrument. The distal end of the innermost tube has about 3/4 of its circumference cut away. What remains is sharpened on each side to a knife like edge. This distal portion, the cutting part, presses against the aspiration port in the middle tube. The innermost tube, the cutting blade, can be either rotated or oscillated by a motor in the handpiece. This action is under the direct control of the surgeon using a foot-pedal acting through a console. Intraocular material that is aspirated into the small port on the side of the middle tube is immediately cut by the action of the rotating cutter and further aspirated through the handpiece into the assistant's syringe (Figure 2). The Roto-Extractor in effect chews intraocular contents into tiny pieces so that they may then be aspirated into the tip and then out of the eye. The Roto-Extractor will chew up or fragment secondary membranes, iris, vitreous, and some cataracts.
FIGURE 2
Schematic diagram of handpiece and tip showing inflow and outflow paths. (Through the courtesy of Nicholas G. Douvas, M.D.).
295
Roto-Extractor TABLE I: CASE NIATERIAL
Total eyes Cataracts
Secondary membranes Congenital Traumatic
Acquired
66 47 19 35 23 8
Our experience has been limited by the nature of our practice largely to anterior segment problems in children and some traumatic cataracts in young adults. We have had no experience with the typical adult cataract of nuclear sclerosis. The basis for this report is 66 eyes in 57 patients (Table I). The age range was 7 weeks to 46 years. Thirty-five of the eyes had congenital cataracts or secondary membranes from congenital cataracts by other procedures; 23 were secondary to trauma; while the remaining 8 eyes developed cataracts of a non-traumatic manner. The average age at the time of surgery for those patients with congenital cataracts was 2.4 years; 9 of these patients were under 6 months of age. The average age for the patients with traumatic cataracts or traumatic secondary membranes was 16.4 years with a range from 5 months to 46 years. The surgical technique is basically simple. The first step is to assemble the Roto-Extractor from its sterile case. This includes placing the motor in the handpiece, attaching the two lines of tubing for the infusion and the suction, attaching the tip, and flushing the system free of air. This requires about five minutes and its performed by the surgeon, his assistant, or an operating room nurse. Using the operating microscope and under general anesthesia, a small limbus based flap is then made either superiorly or superior temporally. This is carried down to the limbus. A Graefe knife ofabout 2.4 mm width is then used to make an incision ofjust this size about 1 mm posterior to the limbus. The tip of this knife then enters the lens at the pupillary border adjacent to the sclerostomy. The tip of the RotoExtractor is then placed into the eye and enters the lens at the opening created by the Graefe knife. As the eye is entered the infusion fluid in the I.V. bottle is started so as to deepen the anterior chamber and raise the intraocular pressure. The cutting port on the tip is directed to the material to be removed, suction is applied by the assistant by means of the syringe, and the cutter blade is activated by the surgeon using the foot pedal. This sequence of positioning the tip, application of suction and activation of the cutter is continued until the pupillary aperture is clear. This sequence of events takes place in the posterior chamber. The nucleus of the lens does not have to be dislocated into the anterior
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chamber. Usually the anterior capsule and cortex of the lens are removed first. Removing the posterior capsule is usually performed near the end of the procedure when a better view of this structure can be obtained. This visualization is aided by coaxial illumination. Included in the removal of the posterior capsule is a portion of the anterior vitreous in nearly all cases. The follow-up, by one or the other authors, has ranged from one day to 10 months with an average of 52.9 days. RESULTS
In general, the results have been excellent. Results in this type of surgery are difficult to quantitate. In children with congenital cataracts, youth and amblyopia make vision an unreliable indicator of surgical success. In many of the traumatic cases associated injury to the cornea or retina precluded meaningful visual results. For a successful result we, therefore, chose as our criterion a pupillary aperture that was optically clear nearly to the edge of the iris. This clear pupillary space was achieved in 63 of 66 eyes. One failure was due to poor technique. The remaining secondary membrane was easily removed at a subsequent procedure. Another failure was caused by a thick secondary membrane. In this eye about one half of the secondary membrane remained after surgery. It could not be cut with the Roto-Extractor. The clear portion was large enough to allow the patient to see 20/30 through the open portion. A third case called a failure was a child with persistent hyperplastic primary vitreous (PHPV). Not all of the retrolental membrane could be removed, but the cataract came out easily. However, this is not to say that the ocular results were excellent in 63 of 66 eyes. In four of the traumatic cases the eyes have either undergone enucleation (one eye) or are in varying stages in the evolution of phthisis (3 eyes). In each of these eyes the traumatic cataract was easily removed from the pupillary aperture but persistent and severe inflammation led to the formation of cyclitic membranes and hypotony. In each case the original trauma was severe and the referring physician and the patient understood the desperate nature of the ocular condition. COMPLICATIONS
The complications have been few compared to the complications of other surgical techniques for doing similar procedure (See Table II). None of the eyes had corneal damage, other than transient edema at
297
Roto-Extractor TABLE II: COMPLICATIONS
Inadequate opening Vitreous to wound Corneal damage Vitreous hemorrhage Hyphema Unplanned iridectomies Prolonged inflammation
3/66 0/66 0/66 3/66 3/66 9/66 9/66
the incision site. This was infrequent and cleared in all eyes in a day or two. None of the eyes have developed retinal detachment. Three of the eyes had scattered blood in the vitreous. This cleared within several weeks without untoward sequelae. Hemorrhage into the anterior chamber has been a minor problem. This has occurred in 3 patients, one of which was the previously mentioned patient with PHPV. In the other 2 patients the hyphema was small and cleared in several days. There are two complications that seem unique to this type of procedure. The first is unplanned iridectomies or sphincterectormies (Figure 3). For the basis of this report this was defined as a surgical defect in the pupillary margin that is grossly visible and that was unplanned.
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FIGURE 3
Unplanned iridectomy. Note the semicircular defect in the pupillary border at 6:00 o'clock position, two days postoperative.
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This occurred in 9 of the 66 eyes. Prolonged inflammation, longer than one week, that could not be accounted for by either the preoperative or postoperative appearance of the eye, occurred in nine eyes also. This was characterized by persistent pain, photophobia, ciliary injection, and anterior chamber and vitreous reaction that responded poorly to topical atropine and steroids. DISCUSSION
The Roto-Extractor will mechanically fragment and aspirate with relative ease iris, vitreous, nearly all types of secondary membranes or after cataracts, traumatic cataracts, and cataracts that occur in children. Since surgical techniques are available that adequately remove many congenital and traumatic cataracts, the value of the Roto-Extractor does not stand out as clearly in these cases. The Roto-Extractor does have the advantage in these cataracts in that in one procedure, the entire cataract can be removed to the edge of the pupil. There is no need for additional procedures for preliminary ripening or softening and later for discission of a secondary membrane. In removing the posterior capsule with the Roto-Extractor, however, a portion of the anterior vitreous is removed also. This is accomplished by the cutting action of the rotating blade so. that there is no traction on the vitreous. Although vitreous is removed or lost by this procedure, none is left in the wound. Current understanding of the mechanism of the adverse effects of vitreous loss in conventional anterior segment surgery is that vitreous incarceration in the wound acts as a traction band to the vitreous attachment to the retina. Postoperatively most of these patients show, by the slit lamp, a paucity to absence of the anterior vitreous in the portion of the posterior segment just posterior to the iris. In several weeks, the vitreous apparently comes forward so that this portion assumes a more normal appearance, but rarely does a vitreous face form. The vitreous has not produced a pupillary block or come forward into the anterior chamber. There have been no apparent ill effects on the retina from this procedure in our series but the longest follow-up is 10 months. Although there is a reluctance by ophthalmic surgeons to remove vitreous electively, there seems to be an increasing realization that if a partial vitrectomy is performed with reasonable care, the eye tolerates the reduced vitreous volume reasonably well.6.7 It is in the cases that are difficult by conventional techniques where the advantages of the Roto-Extractor are more apparent. In cases with dense secondary membranes; lens, vitreous, or iris to a corneal wound;
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Dense secondary membrane immediately preoperative (A) and postoperative (B).
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or bound down or up drawn pupils, the unwanted tissue is relatively easy to remove (Figure 4). Usually an edge or opening into the secondary membrane has to be created either with a knife needle or a sclerotome. The cutting action of the Roto-Extractor works best when there is an edge of tissue to aspirate into the port on the middle tube of the tip so that the cutter blade can fragment or cut the tissue into smaller pieces to be further aspirated. In cases in which the pupil is up drawn or bound down by synechiae, the cutting action of the Roto-Extractor can enlarge the pupil to any desired size. Small pupils, as in cases with cataracts secondary to chronic uveitis, are not a contraindication as with the phaco-emulsifier. In this type of case the opening into the lens or lens material should be made not at the edge of the small pupil, but through the iris at the point of the desired diameter of the eventual pupillary opening. Three cases of PHPV have been operated upon by the authors. Two of the cases were advanced with secondary cataract, shallow chamber, and secondary glaucoma. The third case, done at 8 weeks of age, had only a retrolental membrane with a clear lens. In each case the approach was through the pars plana instead of at the limbus. In each case the lens was removed easily and the membrane with some difficulty in the two advanced cases. This type of case could probably be done also by a limbal approach with the option of closing that wound and converting to a pars plana approach if the need should arise. The anterior chamber is constantly maintained by the gravity fed infusion system. This is from two bottles at different heights connected to the handpiece by a T tube. The low bottle is normally placed about 20 inches above the level of the eye. It is constantly open to maintain a steady level of intraocular pressure. If fluid is leaking around the incision and the chamber is shallowing, the bottle can be raised to compensate for this with an increased flow rate. The higher bottle can be opened by the surgeon with the foot pedal. It is usually activated when active cutting and aspiration are taking place. Because the anterior chamber is constantly maintained is no doubt one of the reasons why we have not seen any corneal edema following this procedure. The youth of the patients and the integrity of the corneal endothelium in this age group also play an important role. Only five of the patients, all with traumatic cataracts, were over 20; the oldest 46. Other investigators will likely comment in the future on the effects of this procedure on the cornea in older patients. Hemorrhage during the procedure is uncommon and easily managed. The infusion pressure can be raised by adjusting the height of the infusion
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bottle till the hemorrhage is controlled. The blood can then be aspirated out of the eye. If the anterior vitreous is removed during the surgery this is automatically replaced by the infusion fluid. At the conclusion of the procedure as the tip is removed, the fluid leaks out of the wound creating a hypotonic eye. Intraocular hemorrhage that was controlled during surgery by the infusion fluid could recur at this point, but this has happened in only a few cases and to a small degree. Because the anterior face of the vitreous is broken, what blood there is in the anterior chamber seems to diffuse back into the vitreous where it may remain scattered or in clumps. This hemorrhage that falls back into the vitreous has in all cases gradually absorbed over several weeks. The Roto-Extractor easily removes iris tissue. For this reason it is well suited to create or enlarge a pupillary opening. Sometimes during the course of the procedure some of the iris tissue at the pupil inadvertently is pulled into the aspirating port. Most of the time this tissue can be pushed out of the port by reversing the action of the syringe and creating positive pressure in, what is normally a negative pressure system, the innermost tube in the tip. In those situations where the iris cannot be freed, it must be cut. This creates a semicircular defect about 1 mm in
FIGURE 5
Comfortable eye one day following surgery in child with bilateral cataracts.
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FIGURE 6
Preoperative (A) and two days postoperative (B) in 5 month old child.
diameter in the pupillary border. This occurs most often as the surgeon is zealously attempting to remove all lens material next to or under the pupillary edge and the assistant creates too much suction pressure with the syringe. This complication occurred nine times in this series. Usually the eyes are white, pain free, and can be refracted or examined with the indirect ophthalmoscope the day after surgery (Figures 5, 6). But in some cases (9 of 63 eyes in this series) severe postoperative inflammation was significant.
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The problem of persistent inflammation in the face of otherwise uncomplicated surgery is more baffling. The clinical picture is, in addition to the patient's complaints of photophobia and pain, a relatively white eye except for ciliary flush, with flare in the anterior chamber, and a slightly hazy vitreous. In all cases the eye was quiet preoperatively, occurring 8 of 9 times in eyes with congenital cataracts or secondary membranes from congenital cataract surgery. It is not related to visible persistent lens material since in each of these cases, the lens was nearly totally removed. The clinical pictures resemble to some degree the sterile inflammation seen after intracapsular extractions in adults.8 It does not seem to be related to iris trauma or inadvertent iridectomies. Perhaps the trauma of the current of the infusion fluids within the eye might create an iritis but this phenomenon is not related to the length of time the tip is in the eye. One explanation is that some foreign material might be introduced into the eye, either from the components of the Roto-Extractor, through improper cleaning, or during sterilization. The most attractive hypothesis is that fragments of lens material fell back into the vitreous. This could occur if the posterior capsule and anterior vitreous face are ruptured early in the process of removing the lens. Because of the presence of the infusion fluid, vitreous would not come forward but fragments ofthe lens that for the moment escaped from the suction current could easily fall back into the vitreous through the defect in the anterior hyaloid face and create a phacolytic uveitis. It is in these patients that photophobia precludes an adequate examination of their vitreous to look for lens fragments. None have been subjected to an examination under general anesthesia to circumvent the photophobia to further elucidate the mechanism. In two of the 9 eyes with prolonged inflammation the surgery was for secondary membranes. In these two cases it is unlikely that there was enough lens cortex present to create a phacolytic uveitis. Perhaps there are several mechanisms for this complication. Other than the discomfort to the patient there seems to be no ill effects from this inflammation. SUMMARY
The Roto-Extractor, designed by Nicholas Douvas, M.D., was used by the authors in 66 eyes for cataracts, secondary membranes, and persistent hyperplastic primary vitreous. The average age of the patients with congenital cataracts was 2.4 years, for traumatic cataracts 16.4 years. The pupil was cleared well in 63 of these eyes. There was no vitreous to the wound in any of the eyes. Unplanned iridectomies and prolonged inflammation were the major complications.
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1. Kelman CD: Phaco-emulsification and aspiration. A new technique of cataract removal. A preliminary report. Am J Ophthalmol 64:23, 1967. 2. Machemer R, Parel J, Buettner H: A new concept for vitreous surgery. 1. Instrumentation. Am J Ophthalmol 73:1, 1972. 3. Shock JP: Phacofragmentation and irrigation of cataracts. A preliminary report. Am J Ophthalmol 74:187, 1972. 4. Douvas NG: The catarct roto-extractor (a preliminary report). Trans Am Acad Ophthalmol Otolaryngol 77:792, 1973. 5. Girard LJ, Hawkins RS: Cataract extraction by ultrasonic aspiration. Vitrectomy by ultrasonic aspiration. Trans Am Acad Ophthalmol Otolaryngol 78:50, 1974. 6. Cerasoli JR, Kasner D: A follow-up study of vitreous loss during cataract surgery managed by anterior vitrectomy. Am J Ophthalmol 71:1040, 1971. 7. Machemer R, Norton EWD: A new concept for vitreous surgery. 3. Indications and results. Am J Ophthalmol 74:1034, 1972. 8. Hogan MJ: Postoperative Iridocyclitis, in symposium: Postoperative cataract complications. Trans Am Acad Ophthalmol Otolaryngol 61:33, 1957.
DISCUSSION
DR P. ROBB MCDONALD. The authors have reported on a fairly extensive series accumulated within a period of one year. There is no question that an era of instrumentation is upon us. Dr Calhoun has discussed the mechanics of the roto-extractor, though I have not used it I have seen it in use. There are now several other instruments of somewhat similar construction. Two that I know of have the cutting orifice on the side and one at the tip. The suction of digested material is controlled by the operator on the handle of the instrument or by an assistant. The SITE instrument (Suction Infusion Tissue Extractor) developed in Philadelphia, has a rotatory cutter on the side of the tip of the instrument as does the roto-extractor and the suction can be graduated by the surgeon. Should the blades become dull it may wind up tissue like spaghetti, by reversing the cutting blade it may unwind. There are other instruments that have been developed in which the cutting blade is at the tip and acts as a guillotine; with this, one avoids the rotatory action which may tear tissue into the rotating blade. Undoubtedly we are on the threshold of many new refinements. Most of the instruments have been developed primarily for vitreous surgery, but because of their cutting action, can also be used for anterior segment surgery, i. e., secondary membranes, traumatic cataracts, etc. My own experience is very limited. I have used it only for secondary membranes resistant to more conventional methods of approach. The results in these few cases were satisfactory except for one of a rather severe postoperative uveitis, which responded in ten days to appropriate therapy. David Shoch many years ago stated "vitreous is a sticky, slimy substance which most surgeons try to avoid." This statement I think still hold true for the conventional cataract operation, though should vitreous be lost, an anterior vitrectomy at the time of surgery has certainly reduced the incidence of those updrawn pupils, red eyes and discomfort in those patients whom we wish we had never seen.
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With these instruments one seldom if ever sees vitreous in the wound of entrance, but I cannot help but wonder what the final outcome of an anterior vitrectomy will be in an infant. In time this might result in traction bands resulting in a retinal detachment. A well performed discission and aspiration of a congenital cataract leaves a minimal posterior capsule with few Elschnig pearls. A small discission of the posterior capsule may be performed if necessary without disturbing the vitreous. There is no question that instrumentation has widened our horizons in ophthalmic surgery and I thank the authors for permitting me to see their manuscript and congratulate them on their results. DR R. D. HARLEY. Mr President. Mr Secretary. We wish to thank Dr P. Robb McDonald for his interesting discussion. Surgery for congenital cataract has undergone many variations in an effort to reduce risk and improve visual results. Our present day method of discission and aspiration through a small needle-sized opening as described by Scheie is a considerable improvement over earlier methods of linear extraction and multiple discissions. Long-term results with significant reduction of late complications have been most apparent. Recently, a group of new modalities utilizing ingenious instruments have been introduced which will require evaluation in terms of immediate and long-term results. Our experience with the Douvas Roto-Extractor would suggest that it offers no great advantage for the removal of the routine congenital cataract. However, it does seem to have a special advantage in certain conditions such as dense secondary membranes, irido-capsular adhesions to corneal scars, certain cases of persistent hyperplastic primary vitreous, dislocated lens, and severe hyphema. The chief advantages of the Roto-Extractor are that surgery can be performed through a small opening, it leaves a clear, black pupillary space with Ino posterior capsule; it is probably less traumatic in complicated cases with dense memiibranes, adhesions or updrawn pupils and it permits earlx ambulation. The chief disadvantages are unplanned sphincterectomnies or iri(lectomies, prolonged inflammation in certain cases, and loss of the anterior vitreouis. Final assessment of results will require time as to its ultimate usefuilness in ophthalmology. Our present viewpoint is that our residenits should become famililiar with the discission-aspiration technique as the primary procedure. For the special problems involving congenital cataracts, the Roto-Extractor and similar instruments vill have a useful purpose. An instrument similar to the Roto-Extractor has beenI developed in the Philadelphia area. It is known as the SITE instrumenit (Suctioni Infusion Tissuie Extractor). A short imlovie illustratinig the use of this instrument wvill be shown. Similar instruments are available and eventuallv the exact indicationis for such proce(dures will be defined.
