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Ritleng Intubation System for Treatment of Congenital Nasolacrimal Duct Obstruction
Mary Rose L. Pe, MD;
John D. Langford, MD;
John V. Linberg, MD;
Terry L. Schwartz, MD;
Naval Sondhi, MD
Arch Ophthalmol. 1998;116:387-391.
ABSTRACT
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Twenty-eight patients (34 eyes) with congenital nasolacrimal duct obstruction underwent silicone intubation with the Ritleng lacrimal intubation system. The technique involves introduction of a Prolene (Ethicon Inc, Somerville, NJ) monofilament guide thread, securely fastened to the silicone tubing, into a tubular metal probe that opens into the inferior meatus. The outcome was evaluated in terms of ease of intubation and objective success rate. Thirty-two (94%) of the 34 lacrimal systems were successfully intubated with the Ritleng system. Difficulty passing the Prolene thread through the probe and out the tip, necessitating conversion to a Crawford intubation system, was encountered in only 2 eyes (6%). The Prolene spontaneously emerged from the nose in 24 (75%) of 32 eyes, making retrieval simple and uncomplicated. The success rate for relieving signs and symptoms of obstruction was 97% (31/32) for the eyes with the Ritleng system and 100% (2/2) for the eyes with the Crawford system. Bicanalicular silicone intubation with the Ritleng intubation system is an easy and effective technique for treatment of congenital nasolacrimal duct obstruction.
INTRODUCTION
Congenital nasolacrimal duct obstruction is a common disorder seen by practitioners in ophthalmology and pediatrics, occurring in approximately 6%1 to 20%2 of term infants and 11% of premature infants delivered at 30 to 36 weeks.3 More than 90% of cases of congenital obstruction resolve spontaneously by 1 year of age.4-5 When congenital nasolacrimal duct obstruction does not resolve spontaneously, surgical treatment must be undertaken to relieve the obstruction, and most patients respond to conventional probing of the nasolacrimal duct.6-7 If probing is unsuccessful, then intubation with silicone stents is an effective treatment for persistent congenital nasolacrimal duct obstruction.8-9
In principle, silicone intubation is a simple procedure, and a variety of instruments and modifications of technique have been devised.10-12 Even experienced surgeons, however, may encounter difficulties, particularly when attempting to retrieve metal probes from within the nose. These difficulties are partly a consequence of the compact anatomy of the nasal cavity in children, with which many ophthalmologists are unfamiliar.
The Ritleng lacrimal intubation system provides a technique for bicanalicular silicone intubation without the need for the retrieval of metal probes from the inferior meatus. The technique involves introduction of a Prolene (Ethicon Inc, Somerville, NJ) monofilament guide thread of the Ritleng intubation set into a tubular Ritleng probe that opens into the inferior meatus. The Prolene spreads out widely in the nasal fossa as it exits the Ritleng probe, making it easier and less traumatic to locate than a metal probe. A silicone tubing, securely fastened to the Prolene, is drawn into the nasolacrimal duct as the Prolene is pulled out the nose. This article documents our experience and success rate with the Ritleng intubation system.
MATERIALS, PATIENTS, AND METHODS
MATERIALS
The Ritleng probe (model S1-1470, FCI Ophthalmics, Marshfield Hills, Mass) is a rigid, hollow, polished stainless steel tube measuring 1 mm in diameter and 105 mm long. The diameter is comparable to that of a Bowman 0 probe (model 7-2520, Katena, Denville, NJ). The superior end of the probe contains a funnel-shaped opening to facilitate introduction of the Prolene monofilament leader and a disk for holding and orientation (Figure 1). The blunt inferior end has a lateral opening 5 mm above the tip to allow the Prolene to exit the probe without impaling the mucosa on the nasal fossa floor. The hollow probe has a narrow slit (0.3 mm wide) that runs the length of the probe from the funnel-shaped entrance to the outlet opening (Figure 2).
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Figure 1. Dimensions of the Ritleng probe. The blunt inferior end has a lateral opening 5.0 mm above the tip. The hollow probe is 1.0 mm in diameter and has a 0.3-mm slit that runs from the funnel-shaped entrance to the outlet opening.
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Figure 2. The Ritleng probe. A funnel-shaped opening on the superior end of the probe facilitates introduction of the Prolene thread. A slit measuring 0.3 mm wide runs the entire length of the hollow probe.
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The Ritleng lacrimal intubation set (model S1-1451, FCI Ophthalmics) consists of silicone tubing firmly attached to a Prolene monofilament leader at each end (Figure 3). The silicone tubing has an outer diameter of 0.64 mm and is 300 mm long. The 2 Prolene leaders are composed of a thicker dark blue initial portion, 0.40 mm in diameter, followed by a thinner light blue portion, 0.20 mm in diameter. Only the thinner portion of the Prolene can slip out of the open slit of the probe (Figure 4).
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Figure 3. The Ritleng lacrimal intubation set. Two Prolene (Ethicon Inc, Somerville, NJ) monofilament threads are solidly attached to each end of silicone tubing.
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Figure 4. The Ritleng lacrimal intubation set. Only the thinner portion of the Prolene (Ethicon Inc, Somerville, NJ) (light blue, 0.20 mm in diameter) can slip out of the open slit of the probe.
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A Ritleng hook (model S1-1480, FCI Ophthalmics) or a small muscle hook is sometimes needed to engage the Prolene under the inferior turbinate (Figure 5).
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Figure 5. The Ritleng hook facilitates retrieval of the Prolene (Ethicon Inc, Somerville, NJ) thread from under the inferior turbinate.
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PATIENTS
Twenty-eight patients (34 eyes) with congenital nasolacrimal duct obstruction were treated using the Ritleng lacrimal intubation system from July 1994 to July 1996. The average age of the patients was 19 months (range, 5 months to 5 years 3 months). There were 17 girls and 11 boys.
The diagnosis of congenital nasolacrimal duct obstruction was based on (1) ophthalmic history, which included symptoms of epiphora, crusting, variable amounts of discharge, and dacryocystitis; (2) ophthalmic evaluation, which showed an increase in tear meniscus, crusting, and, in some, reflux of material from the nasolacrimal sac; and (3) a delay in fluorescein dye disappearance.
All of the patients had previously undergone unsuccessful medical treatment (lacrimal sac massage and topical or systemic antibiotics) and simple lacrimal probing by the referring physician or the authors (J.D.L., J.V.L.,T.L.S., and N.S.). One patient who was initially enrolled in the study was later excluded because the obstruction was found to be above the nasolacrimal duct. In this patient, attempts to pass the Ritleng probe and the Crawford probe were unsuccessful and, therefore, a dacryocystorhinostomy was performed instead. Other exclusion criteria for this study include a history of trauma, facial surgery, radiotherapy, or periocular neoplasm and tearing related to eyelid malposition and external eye disease.
All procedures were performed with the patient under general anesthesia. The nasal passages were inspected with a pediatric nasal speculum. The inferior meatus was packed with cottonoid strips moistened with 4% cocaine solution. The amount of cocaine was kept below the recommended dose of 3 mg/kg of body weight. The lower and upper puncta were dilated. The canaliculi were probed to the lacrimal sac with Bowman 00 and 0 probes to ensure adequate size of the common canaliculus. A Ritleng probe was then passed through the lower or upper canaliculus into the lacrimal sac and rotated 90° to the upright position, and the tip of the probe was passed down the nasolacrimal duct and through the membranous obstruction. The Ritleng probe was turned so that the slit faced in the anteromedial direction. A Bowman lacrimal probe that was passed beneath the inferior turbinate was used to demonstrate metal-on-metal contact, confirming the presence of the Ritleng probe in the nasal cavity. The Prolene monofilament leader was introduced into the probe through the proximal funnel-shaped opening. If mild resistance was encountered in threading the Prolene leader through the probe, the probe and the Prolene were retracted as a unit 1 to 2 mm before more of the Prolene was advanced. Withdrawal of the Prolene alone could cause the filaments to get wedged in the slit of the probe. As the Prolene exited the probe tip into the nasal cavity, it often curled in the nasal cavity and spontaneously emerged from the nose. In other cases, the Prolene accumulated in the nose as a large, tangled web, making it easy to grasp with forceps. If the Prolene could not be directly visualized and grasped with forceps, retrieval of the Prolene was accomplished by passing a small, blunt Ritleng hook or a muscle hook beneath the inferior turbinate. When retrieval of the Prolene was difficult, direct visualization of the area around the inferior meatus was performed with a nasal speculum. Inability to retrieve the Prolene from the nose at this point was an indication to convert to the Crawford system or to dacryocystorhinostomy, depending on the intraoperative assessment. Once the Prolene was removed from the nose, the probe was withdrawn from the nasolacrimal system and separated from the intubation set by sliding the thinner portion of the Prolene out through the slit of the Ritleng probe. The Prolene was pulled from the nose, drawing the silicone tubing into the nasolacrimal duct. A small amount of ophthalmic ointment placed in the medial canthus facilitated passage of the silicone stent. After both canaliculi were intubated, the Prolene guides were removed. The 2 ends of the silicone stents were tied in a single square knot. Two surgeons (J.V.L. and J.D.L. in 13 eyes of 12 patients) used intranasal fixation to the lateral nasal mucosa with a 4-0 chromic absorbable suture about 5 mm inside the nasal vestibule. Intranasal fixation was not performed in the remaining patients (T.L.S. and N.S. in 21 eyes of 16 patients). The ends of the tubing were cut just inside the nose after ensuring that no tension was present in the medial canthus.
Postoperatively, antibiotic ophthalmic drops or ointment were used for approximately 1 week. Parents were asked to minimize rubbing of the patient's eye, but this was a difficult task with small children. If the stent became inadvertently dislodged (laterally displaced), the parents were instructed to tape the stent to the side of the nose with an adhesive tape and bring the child to the medical office for early stent removal. No attempt was made to reposition the stent.
Stent removal, after 2 to 6 months, was performed in the medical office in all patients. After topical ophthalmic anesthetic was applied, with the child held by the parents, the stent was grasped at the medial canthus with blunt forceps and pulled away from the eye, causing anterior displacement. The loop of silicone stent was cut and the single square knot was removed through the inferior canaliculus.13 All stents were removed intact without damage to the canaliculus.
In this study, we evaluated 2 variables: the procedure of intubation with the Ritleng system and treatment of nasolacrimal duct obstruction. Success was defined as (1) easy, uncomplicated retrieval of the Prolene guide thread during intubation and (2) complete resolution of previous signs and symptoms and a normal result of the dye disappearance test in cooperative patients. Unsuccessful cases were characterized by (1) inability to retrieve the Prolene, resulting in conversion to a different procedure, or (2) persistence of symptoms.
RESULTS
We evaluated this intubation technique and the success rate of the Ritleng lacrimal intubation system performed by 4 surgeons (J.V.L, J.D.L., N.S., and T.L.S.) in 28 patients at the West Virginia University Eye Center, Morgantown, and the Midwest Eye Institute, Indianapolis, Ind, from July 1994 to July 1996.
Of the 34 eyes in this study, the surgeons successfully intubated 32 (94%) lacrimal systems with the Ritleng system. In 2 eyes, conversion to the Crawford system was necessary because of difficulties encountered in passing the Prolene through the probe and out the tip. The Prolene spontaneously emerged from the nose in 24 (75%) of 32 eyes, making retrieval easy. When the Prolene did not spontaneously emerge from the nose, retrieval was accomplished by sweeping the Ritleng hook or a small muscle hook beneath the inferior turbinate (6 eyes [19]) or by using forceps under direct visualization of the inferior meatus (2 eyes [6]).
The success rate of initial silicone intubation in relieving signs and symptoms of nasolacrimal duct obstruction in this series was 97% (31/32) for the eyes with the Ritleng system and 100% (2/2) for the eyes converted to the Crawford system. Planned stent removal was performed in 32 of 34 eyes between 2 and 6 months after surgery (mean duration, 3 months). Premature lateral displacement requiring unplanned stent removal occurred 1 week after surgery in 2 (6%) of 32 eyes treated with the Ritleng system. In these 2 patients, the stents were unintentionally dislodged by the child during sleep or during daily activities. In both cases of early lateral displacement, the stent had not been sutured within the nose. Persistence of epiphora and crusting necessitated another Ritleng intubation. Nasolacrimal duct obstruction eventually resolved in these patients after planned stent removal.
There were no intraoperative complications in this study. No ophthalmic injuries occurred from planned or unplanned stent removal in the medical office. Also, no complications associated with the silicone stent, such as punctal erosion, granuloma formation, or corneal erosion occurred.
COMMENT
Congenital obstruction of the distal end of the nasolacrimal duct is caused by a thin, persistent mucosal membrane (Hasner membrane); the rest of the nasolacrimal duct is usually normal.14 Spontaneous perforation of the membrane frequently occurs some time after birth, usually before 6 months of age,15 and continues throughout the second year of life with decreasing frequency.16 If congenital obstruction persists, conventional probing of the nasolacrimal duct is generally successful.6-7 However, if simple probing is unsuccessful, silicone stent intubation is more likely to result in a cure.8-9 Previous studies2, 6, 16-21 suggest that any intervention for congenital nasolacrimal duct obstruction should be delayed until 12 to 18 months of age because early probing destined for spontaneous resolution might result in local trauma and induce canalicular and ductal stenosis.22 A delay in treatment, however, also carries certain risks, including the predisposition to chronic and recurrent dacryocystitis that may also induce permanent stenosis of the lacrimal passages.23-25
Silicone intubation is an effective treatment for congenital nasolacrimal duct obstruction in children who do not respond to conservative medical treatment and simple nasolacrimal duct probing.8-9,11, 13, 26-35 The stent is thought to produce nasolacrimal duct patency by maintaining an opening as the edges of the membranous obstruction heal around the stent.8-9 Silicone intubation generally avoids the need for dacryocystorhinostomy, a more extensive operation, in infants and young children with congenital nasolacrimal duct obstruction. The success rates reported for silicone intubation range from 66% to 100%,8-11,13, 26-27,30 generally decreasing with age.26, 30 Our success rate in this study is comparable to previously reported results.
Many authors11, 34, 36-38 have described the use of silicone intubation in the treatment of congenital and acquired lacrimal drainage disorders. Silicone is soft, relatively inert, and flexible. A variety of intubation sets have been described, generally consisting of a silicone tube bonded or glued to a rigid metal probe.10, 34 Several types of probes are available, varying in malleability and design. Rigid probes facilitate passage through the lacrimal drainage system but may cause injury to the delicate canaliculi and nasal mucosa. Ideally, probes should be sufficiently malleable to avoid injury of the lacrimal drainage system. The Crawford intubation set is popularly used because the probes are relatively malleable. It consists of silicone tubing (inside diameter, 0.63 mm; outside diameter, 1.19 mm) attached to a light stainless steel wire (0.50 mm in diameter) with an enlarged "olive tip" end (1.00 mm in diameter) to minimize damage to the tissues. The olive tip of the probe can be engaged in the nose with a specially designed Crawford hook. Like other metal probes, however, retrieval of the Crawford probe from the nose is not always easy.34-35
The main difficulty with traditional rigid metal probes is retrieval of the probes from the inferior meatus. The inferior meatus is the space below the level of the ostium of the nasolacrimal duct that separates the lateral nasal wall from the bullous inner aspect of the inferior turbinate (Figure 6). The inferior meatus is narrow and obliquely angled. Since the nasolacrimal duct is oriented nearly vertically, a standard straight lacrimal probe emerging from the ostium will tend to press against the mucosa of the lateral wall and may dissect a false passage beneath the mucosa.39 Furthermore, attempts to grasp the probe with a hook or hemostat may be difficult, resulting in trauma to the mucosa, bleeding, and lengthy surgery. The Prolene suture introduced by the Ritleng system has the advantage of being soft, atraumatic, and more easily retrieved from the nasal cavity. Indeed, the Prolene spontaneously emerges from the nose in most patients.
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Figure 6. A vertically oriented lacrimal probe in the nasolacrimal duct will tend to press against the mucosa of the lateral wall as it emerges from the ostium.
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Use of a simple square knot to join the ends of the stent, as initially described by Ratliff and Meyer,13 allows the tube to be easily removed through the puncta and canaliculi. This eliminates the difficult and sometimes impossible retrieval of the tube from beneath the inferior turbinate of a child in a medical office setting. However, a potential complication of silicone intubation without intranasal fixation is inadvertent lateral displacement of the stent when the child rubs the eye. Lateral displacement was seen in 2 patients with Ritleng intubation without intranasal fixation, requiring early stent removal 1 week after intubation. In both patients, persistent epiphora resulted after early stent removal. Various techniques40-41 for the repositioning of laterally displaced stents have been described, but these were not attempted in this study because successful repositioning usually requires a second procedure with the patient under general anesthesia. Persistence of epiphora necessitated a second Ritleng intubation 1 week after removal in the first patient and 7 months after removal in the second patient. Both second stenting procedures were successful.
Our results indicate that bicanalicular silicone intubation with the Ritleng intubation system is an effective treatment for patients with congenital nasolacrimal duct obstruction. We found retrieval of the Prolene monofilament leader to be easy, even in the hands of relatively inexperienced residents-in-training. There is minimal nasal bleeding and trauma to the nasal mucosa. Because the Prolene monofilament is easier to retrieve, infracture of the inferior turbinate is rarely necessary. Operating time can be kept short, thereby improving patient care, reducing cost, and decreasing potential morbidity.
AUTHOR INFORMATION
Accepted for publication November 13, 1997.
Presented in part at the Annual Meeting of the Association for Research in Vision and Ophthalmology, Ft Lauderdale, Fla, May 12, 1997.
Reprints: John V. Linberg, MD, Department of Ophthalmology, West Virginia University Health Sciences Center, PO Box 9193, Morgantown, WV 26506-9193 (e-mail: jlinberg{at}access.mountain.net).
From the University Eye Center, West Virginia University, Morgantown (Drs Pe, Langford, Linberg, and Schwartz), and the Midwest Eye Institute, Indianapolis, Ind (Dr Sondhi). None of the authors have a commercial or proprietary interest in any of the products or companies mentioned.
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