Introduction

Nasolacrimal duct (NLD) obstruction is a common disorder that is clinically manifested by the presence of tearing and/or infection. NLD obstruction traditionally has been treated with external dacryocystorhinostomy (external DCR). Toti [17] first described the technique of external DCR in 1904; this was later modified by the addition of a mucosal flap suture [6] and the placement of silicone tubes in the lacrimal system [6]. An endonasal approach to DCR was described by Caldwell [4] as early as 1893 and later by West [18] and Jokinen [10]. However, surgical visualization through the nostril was inadequate due to the angles of the approach and poor illumination of the nasal operative site. Therefore, external DCR became the treatment of choice for nasolacrimal duct obstruction. Recently, the advent of fiberoptic endoscopic surgical instruments and techniques on the one hand and the risk of epicanthus because of scarring on the other have rekindled interest in endoscopic DCR.

Increasing numbers of surgeons (ophthalmologists and otolaryngologists) are performing endoscopic endonasal DCR (endoscopic DCR) as an alternative to external DCR. Overall, three groups of procedures are currently practised: external DCR, surgical endoscopic DCR without laser [10] or with contact laser [19] and the transcanalicular procedure with or without laser.

While numerous authors have described various techniques for external or endonasal DCR, the basic steps in the procedure are the same [6, 7, 16, 18].

Historically, external DCR has yielded success rates of 90 to 98% [16, 8, 9, 14], whereas the success rates for endoscopic DCR have been reported to be between 63 and 100% [8, 9, 12, 20]. The wide range in success rates for endoscopic DCR may be due to the differences in the level of mastery of endonasal anatomy and endoscopic surgical equipment by the surgeons.

The retrocaruncular technique is frequently used to approach the medial orbit and the orbital apex [15]. The main landmark in this area is Horner's muscle, for which the early description and anatomy by Duverney and later by Horner has been well summarized by Reifler [13]. We have used the retrocaruncular approach for use of the Horner Duverney muscle for the treatment of lagophthalmos [1, 2]. With this technique we have increased our experience in approaching the insertion of this muscle on the posterior lacrimal crest through a conjunctival incision. Therefore, we have extended the dissection to create a new technique for the retrocaruncular approach for DCR: RCDCR. In this technique, by using the microscope, ophthalmologists will have easier access compared to the endonasal approach.

Materials and methods

Methods

Between June 2002 and January 2003 ten patients underwent DCR through a retrocaruncular approach under general anesthesia in eight cases and under local anesthesia with monitored anesthesia care in two cases. One case had bilateral RCDCR, therefore the number of procedures was eleven. After intravenous sedation, the nasal vault was packed with 0.5-inch cotton gauze soaked in 5% xylocaine. The medial canthus, canaliculi, upper and lower eyelids and lacrimal sac region were infiltrated with 2% lidocaine. In cases performed under local anesthesia, topical ocular anesthetic is instilled in the operative eye. Infraorbital and/or anterior ethmoidal nerve blocks have been performed as well.

Description of the procedure

A titanium curved shield is applied on the cornea for protection using methylcellulose as the interface (Fig. 1). Conjunctival incision is performed between the semicircular conjunctival fold and the caruncula, with eyelids retracted under traction of 5-0 silk stitches. Using a Colorado needle an incision is carried deeper between Horner's muscle and the orbital fat until the insertion of Horner's muscle on the posterior lacrimal crest is reached (Fig. 2). The periosteum is incised behind the posterior lacrimal crest and separated from the bone with a periosteal elevator in the whole area of the lacrimal fossa (Fig. 3). The lacrimal sac is retracted upwards with skin hooks and incised from its superior pole towards the nasolacrimal duct with a curved blade (Fig. 4). A probe can be inserted in the canaliculus in order to check the patency of the common canaliculus after removal of the skin hooks. Using a Kerisson rongeur, the lacrimal bone in the lacrimal fossa and part of the anterior lacrimal crest is removed (Fig. 5). Nasal mucosa is incised semi-circularly under the pressure of two cotton tips introduced in the nostril. A 6-0 goretex suture is placed on the nasal mucosa and then through the lacrimal sac mucosa and finally sutured to perform the anastomosis (Figs. 6, 7). The conjunctiva is closed with 8-0 vicryl sutures (Fig. 8).

Fig. 1.
figure 1

A titanium shield is applied on the cornea. A conjunctival incision is performed between the semicircular conjunctival fold and the caroncula

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Fig. 2.
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Using a Colorado needle, incision is carried deeper between Horner's muscle and orbital fat until the insertion of Horner's muscle on the posterior lacrimal crest is reached. Common canaliculus is drawn between Horner's muscle and the anterior limb of the medial canthal tendon

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Fig. 3.
figure 3

The periosteum is incised behind the posterior lacrimal crest and separated from the bone with a periosteal elevator at the level of the lacrimal fossa

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Fig. 4.
figure 4

The lacrimal sac is retracted upwards with skin hooks and incised from its superior pole towards the nasolacrimal duct. A probe can be inserted in the canaliculus in order to check the patency of the common canaliculus

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Fig. 5.
figure 5

Using a Kerisson rongeur, the lacrimal bone and part of the anterior lacrimal crest is removed. Nasal mucosa is incised semi-circularly under the pressure of two cotton tips

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Fig. 6.
figure 6

A 6-0 goretex or vicryl suture is placed on the nasal mucosa and then through the lacrimal sac mucosa

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Fig. 7.
figure 7

Final anastomosis is performed under the microscope control using long-tipped retractors. Conjunctiva is sutured with 8-0 vicryl stitches

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Fig. 8.
figure 8

Instruments used for this technique: lacrimal sac retractor with a notch tip, bevel blade and long Kerisson rongeur

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Results

Table 1 summarizes the results. Irrigation of the lacrimal system by syringing was patent at the end of the follow-up in all the patients except two cases: the average success rate was 82%. All the patients patent to syringing were free of their preoperative symptoms, except one who developed air reflux through the lacrimal point when blowing. The follow-up ranged from 1 to 6.5 months, with an average of 2.81 months. For the two failures, one patient was operated on again with a cutaneous approach, with a final good patency to syringing.

Table 1. Results of RC DCR surgery regarding patency to lacrimal syringing (CDCR cutaneous approach for DCR, RC DCR retrocaroncular approach for DCR)
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Three cases were bilateral, two using a cutaneous approach (CDCR) and a RCDCR, the other one having bilateral RCDCR. All three were cured on both sides.

Discussion

What is the effectiveness of the previous methods: endonasal DCR compared with external DCR? A comparative study of endonasal and external DCR consisted of 60 patients undergoing 64 DCR procedures and divided equally into external and endonasal groups [8, 9].The two reports pertaining to this study were from the same center. The data for the external DCR group were identical in both reports, with a success rate of 100% at 6 months postoperatively and 91% at 1 year as defined by patency irrigation. The data for the endonasal DCR group varied from 63% with laser [8] to 75% without laser [9].

In a survey on the results of endonasal DCR, Woog [17] reported a success rate between 61 and 100%. With the advent of the rigid fiberoptic endoscope and its use in para-nasal sinus surgery, there has been renewed interest over the past decade in endonasal surgery to correct primary [3, 8] and recurrent [3, 19] lacrimal obstruction without or with mitomycine [5].

What is the effectiveness of retrocaruncular DCR compared with external or endonasal DCR? In our first report of eleven cases with 82% good results, RCDCR can be judged to be of similar efficacy as the cutaneous or endoscopic approaches.

What are the relative indications, advantages, contraindications and limitations of this procedure? The main indication for RCDCR is cosmetic purposes, as conjunctival incision avoids, like the endoscopic approach, the risk of epicanthus or a visible cutaneous scar. RCDCR can be performed in case of nasolacrimal obstruction even if the sac is dilated. However, currently the technique does not allow for the combined treatment of a common canaliculus obstruction. Potential indications for primary endonasal DCR are similar to those for external DCR, except in the case of common canaliculus obstruction, which is more difficult to approach with the endonasal technique. The main contraindications are suspicion of a lacrimal sac tumor to avoid orbital spread and associated lacrimal lithiasis. Limitations of the procedure are the narrow surgical field and the unusual location of surgery for most ophthalmologists.

What variations in patient selection, surgical technique and postoperative care may influence surgical success rates? Various authors have suggested other factors such as the etiology of nasal mucosa pathology to potentially alter the outcome of DCR surgery and influence patient selection for this procedure. However, our limited number of cases does not allow us to draw final conclusions about this.

Conclusion

The retrocaruncular approach is a valuable technique for dacryocystorhinostomy, especially regarding the cosmetic advantages.