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Journal Français d'Ophtalmologie
Volume 33, n° 3
pages 145-151 (mars 2010)
Doi : 10.1016/j.jfo.2010.01.013
Received : 18 May 2009 ;  accepted : 22 December 2009
Pushed monocanalicular intubation : A preliminary report
Intubation mono-canaliculonasale « poussée »
Étude préliminaire

B. Fayet a, , E. Racy b, G. Renard a
a Department of Ophthalmology, Hôtel-Dieu de Paris, University of Paris VI Medical School, Paris, France 
b ENT, Clinique Saint-Jean-de-Dieu, Paris, France 

Corresponding author at: Department of ophthalmology, Hôtel-Dieu de Paris, 1, place du Parvis Notre-Dame, 75181 Paris Cedex 04, France.

To study the behavior of a “pushed” monocanalicular stent by means of nasal endoscopy.

Patients and Methods

Four children (six affected sides) with congenital nasolacrimal duct obstruction were treated with monocanalicular intubation with an anchoring plug. The children’s mean age at the time of the operation was 33 months (range, 30–37 months). The procedure began with probing in order to verify (a) dacryostenosis (simple or extensive nasolacrimal duct impatency) and (b) the metal-to-metal contact in the lower nasal meatus. The stent was similar to a MonokaTM, but the guide (a malleable stainless steel probe) is located inside the silicone stent rather than projecting from it. The silicone’s total length is 40 mm and the external diameter 0.96 mm. Simultaneously, the guide acts to catheterize the nasolacrimal duct by pushing the silicone through the upper and lower parts of the outflow system. The guide is removed via a punctal approach. This mode of intubation dispenses with the nasal recovery step. Nasal endoscopy was used to monitor (a) the position of the stent in the lower nasal meatus (free or submucosal), (b) mucosal damage and bleeding, and (c) the behavior of the silicone tube during removal of the guide.


Because of the complexity of nasolacrimal ducts, two of the six sides were treated with the classical Monoka intubation method of pulling the silicone tubing out from the nasal exit of the duct (the pull technique). The pushed intubation method was used for the four simple nasolacrimal stenoses, with no problems whatsoever. In all four cases, endoscopic examination showed (a) no submucosal tunneling (false passage), (b) no noteworthy mucosal damage, and (c) no retraction (bunch-up) of the silicone tube during the metal guide removal. No particular complications were reported during the procedure or the intubation period, which lasted an average of 3 weeks. The stents were removed in the consulting room. Tearing ceased during the 1st week in two cases, during the intubation period. Tearing persisted throughout the intubation period in the other two cases, but ceased during the week following stent removal. The follow-up lasted 2 months.


The pushed procedure simplifies monocanalicular nasal intubation. Its indications remain to be determined.

The full text of this article is available in PDF format.

Étudier par endoscopie nasale le comportement d’une intubation mono-canaliculonasale « poussée ».

Patients et méthode

Quatre enfants (6 côtés) présentant une imperforation lacrymo-nasale permanente, ont été traités par intubation mono-canaliculonasale à fixation méatique autostable. L’âge moyen au moment de l’opération était de 33 mois (extrêmes 30 et 37). L’intervention débutait par une exploration instrumentale. Elle vérifiait l’existence d’une imperforation lacrymo-nasale simple et la liberté de la sonde dans le méat nasal inférieur (contact métallique). La sonde employée est proche des sondes mono-canaliculaires à fixation méatique autostable classiques. Mais son mandrin est placé à l’intérieur de la sonde et non dans son prolongement. La longueur hors tout est de 40 mm. Le diamètre externe est 0,96 mm. Dans le même temps, le mandrin cathétérise les voies lacrymales et pousse le silicone à l’intérieur. L’ablation mandrin se fait par voie « haute ». Cette intubation poussée est dépourvue d’étape de récupération nasale. L’endoscopie nasale étudiait la liberté de la sonde dans le méat nasal inférieur (trajet sous-muqueux ou libre), l’importance du traumatisme muqueux, et le comportement de la sonde de silicone durant l’ablation du mandrin.


Deux côtés ont été opérés avec une intubation tirée classique, en raison d’une sténose lacrymo-nasale importante. Quatre intubations poussées ont été posées sans difficulté (4 sténoses lacrymo-nasales simples). L’examen endoscopique montrait dans ces quatre cas : une absence de trajet sous-muqueux, de traumatisme muqueux particulier, et de rétraction du silicone au moment de l’ablation du mandrin. Aucune complication particulière n’a été signalée durant l’intervention et durant l’intubation (durée moyenne 3 semaines). Les sondes ont été retirées en consultation après 3 semaines d’intubation. Deux larmoiements ont disparu dès la première semaine alors que l’intubation était encore en place. Le larmoiement a persisté durant toute la phase d’intubation pour les deux autres patients. Ce larmoiement a disparu dans la semaine qui a suivi l’ablation du matériel. Tous les larmoiements ont disparu. Le recul moyen est de 2 mois.


L’intubation poussée tend à simplifier l’intubation mono-canaliculonasale. La place que pourrait prendre l’intubation poussée reste à définir.

The full text of this article is available in PDF format.

Keywords : Lacrimal apparatus diseases, Lacrimal duct obstruction, Dacryocystitis, Intubation, Congenital nasolacrimal duct obstruction

Mots clés : Appareil lacrymal, Maladies lacrymales, Sténose lacrymo-nasale, Imperforation lacrymo-nasale, Intubation


Canalicular silicone intubation is the treatment of choice for persistent congenital nasolacrimal duct obstruction after unsuccessful probing [1]. The classical method has been to insert the stent into the nasolacrimal duct and then to pull the silicone tubing inferiorly from the nose (the “pulled” technique) [2, 3, 4]. Pulled nasolacrimal intubation stents are composed of a silicone tube attached at each end by a metal or thread guide (in cases of bicanalicular intubation), or by a metal or thread guide at one end and an anchoring plug at the other end (in cases of monocanalicular intubation). The guide (made of malleable stainless steel or flexible PEEK thread) is used to catheterize the lacrimal ducts down to the inferior nasal meatus. The guide is then recovered using the inferior approach and withdrawn from the nasal fossa. This secures the silicone within the lacrimal duct.

“Pushed” nasolacrimal duct intubation is based on the same principles as Werner Forssmann (1904–1979) vascular catheterization, routinely used for vascular procedures. In the pushed intubation procedure, the guide is no longer an extension of the silicone tube, but it is placed inside the tube itself. Here, the guide acts as an introducer that pushes the silicone tube into the nasolacrimal duct. The guide is then withdrawn back out from the ducts, leaving the tube in place, thus avoiding any nasal recovery and its inherent risks.

Pushed intubation procedures are already used in ophthalmology [5, 6] and include the Bigé Self-Retaining Bicanaliculus Intubation Set (FCI, France Chirurgie Instrumentation) and the Nunchaku bi-canaliculonasal stent.

The device’s behavior during withdrawal of pushed intubation, regardless of the material used, is poorly documented. It may retract under the nasal mucosa, or even inside the lacrimal sac, rendering the nasolacrimal intubation ineffective.

We report a small pediatric series of pushed intubation procedures. We used a new monocanalicular stent (Figure 1) called the Pushed Monoka with an anchoring plug for meatus fixation. The anchoring plug is similar to one on the original Monoka [7]. The surgical procedure was monitored by means of intraoperative nasal endoscopy.

Figure 1

Figure 1. 

Pushed Monoka. Black open arrow, dotted line: Muff. Black arrow: Guide (malleable stainless steel probe); White arrow: Silicone tube.


Materials and methods

Four children with permanent congenital nasolacrimal duct obstruction refractory to one or several probing procedures attempted before the age of 12 months were treated by means of pushed intubation.

The families gave their written informed consent.

The procedure took place as follows. (i) General anesthesia was induced with a facial mask. (ii) For probing exploration, the canthal region was swabbed with ophthalmic aqueous polyvidone iodine (Betadine™) solution. The lacrimal ducts were then explored with a lacrimal probe. (iii) The patient was placed under mechanical ventilation, and the larynx was protected by orotracheal intubation and oropharyngeal packing. (iv) For the pushed intubation procedure (Figure 1, Figure 2, Figure 3, Figure 4), we used a new monocanalicular stent (Figure 1). The total length was 40 mm and the external diameter 0.96 mm. The metallic guide is presented inside the silicone tube. The combination of the guide (malleable stainless steel probe) and the monocanalicular silicone tube will be referred to as the Pushed Monoka (PM). The upper lacrimal punctum was carefully dilated. The PM was pushed through the upper canaliculus all the way to the “hard stop” of bony contact. While maintaining bony contact, the PM was rotated to catheterize the lacrimal sac and the nasolacrimal duct (the same technique as for probing) [8]. A larger smooth probe (Bowman 2/0, for example) was very carefully guided blindly into the lower nasal meatus until metal-to-metal contact was felt. Very delicately, the PM was moved by the endonasal probe (8). The metallic guide was removed from the PM by the canthal route. The anchoring plug of the PM was maintained in contact with the upper punctum. The guide was withdrawn very gently by pulling on its external part with a gentle rotation movement. The metallic guide of the PM must be withdrawn along the axis of the lacrimal sac. The anchoring plug was seated securely in the punctum using a punctum plug inserter (Disposable Punctum Dilator and Plug Inserter, FCI S1-3090). (v) The intraoperative endoscopic monitoring began just after the metallic contact was achieved. The nasal mucosa was retracted by inserting a strip impregnated with 1% adrenalin Xylocaine. The endoscope was a rigid pediatric-size device, 2.7 mm in diameter, and equipped with a 0° Panoview. The inferior nasal meatus was visualized after careful medialization of the nasal process of the inferior turbinate. Endoscopic inspection focused on the location of the PM in the inferior nasal meatus (free or submucosal), the behavior of the silicone tube during metallic guide removal, bleeding due to instrumental trauma, and intubation. (vi) Postoperative treatment was Neomycin-dexamethasone eye drops four times daily for 7 days. The patients were followed up on D1, D21 (silicone removal), and D60.

Figure 2

Figure 2. 

Right side. Beginning vertical catheterization.


Figure 3

Figure 3. 

Right side. Guide removal, canthal view. (a) Vertical catheterization. The head of the Pushed Monoka meets the lacrimal meatus. (b) The head of the Pushed Monoka is held against the meatus with an instrument while the guide is extracted. (c) The guide must be pulled along the axis of the vertical lacrimal ducts.


Figure 4

Figure 4. 

Guide removal, endoscopic view. The Pushed Monoka is in the lower nasal meatus. The inferior nasal meatus was visualized after careful medialization of the nasal process of the inferior turbinate (white star). White open arrow: End of the silicone. Black open arrow: End of the metallic guide.



Four children (six sides) with permanent congenital nasolacrimal duct obstruction (dacryostenosis) were treated during the same session.

Intraoperative instrumental investigation showed simple impatency on four sides (Hasner membrane) and extensive nasolacrimal duct stenosis on both sides. In the first patient with extensive stenosis (case #3, right-hand side), the silicone tended to bunch up on the metallic probe, reducing the distance from the fixation head to the white extremity of the metallic guide. The PM was immediately withdrawn and examined, showing that the metallic probe had pierced the end of the silicone (Figure 5). It was therefore decided to revert to pulled intubation with the classical Monoka technique (Monoka FCI, reference S1-1630). In the second case of extensive stenosis (case #4), probing immediately ruled out the use of pushed intubation (Table 1). Here too we opted for a pulled Wide Collarette Monoka intubation (Monoka FCI, reference S1-1630).

Figure 5

Figure 5. 

Patient #3, Right side. Complex nasolacrimal stenosis. Only the metallic probe will cross the stenosis, leaving behind the bunched up silicone tubing. The Pushed Monoka was immediately withdrawn and examined, showing that the metallic probe had pierced the end of the silicone.


The intraoperative endoscopic findings are summarized in Table 1.

As for the functional outcome and complications, the first two patients’ tearing disappeared completely during the 1st week of intubation. In the other two patients, tearing persisted on both sides during the two successive intubations. No photophobia occurred and fluorescein staining tests were negative. No anatomical complications occurred. The PM devices were withdrawn without difficulty in the exam room. The stents were intact, as shown by biomicroscopy. The tearing subsequently disappeared during follow-up. The results are summarized in Table 2.


Pulled intubation is commonly used for lacrimal duct surgery. In contrast, despite its apparent simplicity, pushed intubation is not widely used in ophthalmology [5, 6].

Our endoscopic findings showed that pushed intubation was not associated with more mucosal bleeding than intubation and/or probing, even though the pushed stent is broader (0.96 mm) than classical lacrimal stents (0.64 mm). In addition, in the four cases of simple lacrimal impatency, PM insertion was relatively simple. In particular, the silicone tube did not bunch up during metallic guide withdrawal. The silicone tube remained in place in the middle of the inferior nasal meatus.

Our endoscopic findings confirm the efficacy of pushed intubation when the PM readily crosses the nasolacrimal blockage. It should be noted that the end of the PM is identical to that of the Infant Bika stent (FCI reference, S1-1100), which has been in routine use for many years [4].

Which types of nasolacrimal impatency might benefit from pushed intubation?

Congenital nasolacrimal duct obstruction can stem from a wide variety of mechanisms, ranging from nasolacrimal valve impatency (Hasner membrane) to bony obstacles and separately or simultaneously involve the lower turbinate, the maxillary bone, and inferior nasal process mucosae.

For want of a better technique, it is the surgeon’s tactile perception of the probe contact during probing for dacryostenosis that distinguishes between simple and complex obstacles.

We consider that pushed intubation is inappropriate for complex nasolacrimal stenosis, as there is a danger that only the metallic probe will cross the stenosis, leaving behind the bunched up silicone tubing (Figure 5).

How can one be sure that pushed intubation does not follow a false passage?

All forms of probing and intubation carry a risk of false passage [9, 10, 11]. In the present setting, there is a risk that the entire Pushed Monoka could remain submucosal in the lateral wall of the nasal fossa or remain in the mucosa of the nasal process of the inferior turbinate.

The frequency of false passage during probing or intubation is well documented [9, 12, 13]. False passage will inevitably affect the functional outcome.

During pulled intubation, most cases of false passage can be corrected to a certain extent: during recovery of the stent by the lower nasal approach, a variable length of nasal mucosa will be damaged.

In contrast, with pushed intubation, removal of the metallic guide by the upper approach will not correct the false passage. Preventive endonasal screening for false passage is therefore crucial prior to pushed intubation.

Nasal endoscopy can detect all cases of false passage [9, 12, 14, 15, 16]. However, in order to inspect the inferior nasal meatus correctly, it is usually necessary to infracture the lower turbinate [17, 18, 19], thus complicating the procedure and creating an additional risk of bleeding from the nasal mucosa.

Detecting the metallic contact within the nasal fossa [8, 20, 21, 22] is probably simpler than direct visualization, but its accuracy and safety remain to be demonstrated in larger series.

Is 40 mm the right length for a pushed stent?

Endoscopic examination showed that the free part of the PM surfaced from the floor of the nasal fossa in all four patients. However, in children, the distance between the upper meatus and the bony contact is about 6–8 mm. The lacrimal sac measures about 12 mm vertically. The average distance between the nasal process of the inferior turbinate bone is 10 mm. The total length is therefore about 30 mm. The four children in this serie were relatively old (mean, 33 months), and the stent might well be too long for younger and/or smaller children. Shorter stents will be tried soon.


Pushed intubation may simplify nasal monocanalicular intubation. Probing is crucial to confirm the indication of pushed intubation and, probably, to choose the length of the Pushed Monoka stent. The appropriate place for pushed intubation in the treatment of children with nasolacrimal impatency remains to be determined.

Conflict of interest

Dr. Bruno Fayet holds the patent for the Pushed Monoka. None of the authors has financial interest in any of the products mentioned.


Dr. James Katowitz (University of Pennsylvania School of Medicine, Philadelphia, PA, USA) for his helpful advice.


Katowitz J.A., Welsh M.G. Timing of initial probing and irrigation in congenital nasolacrimal duct obstruction Ophthalmology 1987 ;  94 : 698-705
Büsse H., Serra F. Intubation technique for dacryostenosis Orbit 1984 ;  3 : 111-113
Crawford J.S. Intubation of obstructions in the lacrimal system Can J Ophthalmol 1977 ;  12 : 289-292
Fayet B., Ruban J.M. Intubations des voies lacrymales Les voies lacrymales. Paris: Masson (2006).  429-455
Lekskul A., Khamapirad B., Nimvorapun T. Simple technique for silicone intubation in congenital nasolacrimal duct obstruction J Med Assoc Thai 2004 ;  87 : 1082-1086
Kurihashi K. Bicanalicular silicone intubation using three-piece silicone tubing: direct silicone intubation Ophthalmologica 1993 ;  206 : 57-68
Fayet B., Assouline M., Bernard J.A. Monocanalicular nasolacrimal duct intubation Ophthalmology 1998 ;  105 : 1795-1796 [cross-ref]
Katowitz J.A., Low J.E., Covici S.J., Goldstein J.B. Probing and silastic intubation Pediatric Oculoplastic Surgery New York: Springer (2002).  309-324
Ram B., Barras C.W., White P.S., MacEwen C.J., Young J.D. The technique of nasendoscopy in the evaluation of nasolacrimal duct obstruction in children Rhinology 2000 ;  38 : 83-86
Sener E.C., Onerci M. Reappraisal of probing of the congenital obstruction of the nasolacrimal system: is nasal endoscopy essential? Int J Pediatr Otorhinolaryngol 2001 ;  58 : 65-68 [cross-ref]
Busse H., Muller K.M., Kroll P. Radiological and histological findings of the lacrimal passages of newborns Arch Ophthalmol 1980 ;  98 : 528-532
MacEwen C.J., Young J.D., Barras C.W., Ram B., White P.S. Value of nasal endoscopy and probing in the diagnosis and management of children with congenital epiphora Br J Ophthalmol 2001 ;  85 : 314-318 [cross-ref]
Ingels K., Kestelyn P., Meire F., Ingels G., Van Weissenbruch R. The endoscopic approach for congenital nasolacrimal duct obstruction Clin Otolaryngol Allied Sci 1997 ;  22 : 96-99
Kouri A.S., Tsakanikos M., Linardos E., Nikolaidou G., Psarommatis I. Results of endoscopic assisted probing for congenital nasolacrimal duct obstruction in older children Int J Pediatr Otorhinolaryngol 2008 ;  72 : 891-896 [cross-ref]
Wallace E.J., Cox A., White P., Macewen C.J. Endoscopic-assisted probing for congenital nasolacrimal duct obstruction Eye 2006 ;  20 : 998-1003 [cross-ref]
Lueder G.T. Endoscopic treatment of intranasal abnormalities associated with nasolacrimal duct obstruction J AAPOS 2004 ;  8 : 128-132 [cross-ref]
Gardiner J.A., Forte V., Pashby R.C., Levin A.V. The role of nasal endoscopy in repeat pediatric nasolacrimal duct probings J AAPOS 2001 ;  5 : 148-152 [cross-ref]
Yagci A., Karci B., Ergezen F. Probing and bicanalicular silicone tube intubation under nasal endoscopy in congenital nasolacrimal duct obstruction Ophthal Plast Reconstr Surg 2000 ;  16 : 58-61 [cross-ref]
Lim C.S., Martin F., Beckenham T., Cumming R.G. Nasolacrimal duct obstruction in children: outcome of intubation J AAPOS 2004 ;  8 : 466-472 [cross-ref]
Dryden R.M., Popp J.C. Visualization of the probe tip during lacrimal outflow system probing and intubation Ophthalmic Surg 1985 ;  16 : 776-778
Yap E.Y., Yip C.C. Outcome of late probing for congenital nasolacrimal duct obstruction in Singapore children Int Ophthalmol 1997 ;  21 : 331-334 [cross-ref]
Cibis G.W., Jazbi B.U. Nasolacrimal duct probing in infants Ophthalmology 1979 ;  86 : 1488-1491

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