Outcomes of canalicular trephination versus canaliculodacryocystorhinostomy in common canalicular blocks.

AIM: This study aimed to compare the outcomes and efficacy of canalicular trephination with monocanalicular stenting and canaliculodacryocystorhinostomy (canaliculoDCR) with silicone intubation.
MATERIALS AND METHODS: A prospective comparative study was done in 30 patients (30 eyes) with common canalicular blocks who were randomized into two groups. Fifteen patients underwent canalicular trephination with monocanalicular stenting and 15 patients underwent canaliculoDCR with silicone intubation. Common canalicular obstruction was diagnosed by preoperative syringing and the location of block was confirmed on probing. Stents were kept in both the groups for 3 months and followed up till 6 months postoperatively. Success was defined based on both anatomical and functional outcomes. Anatomical success was defined by the free passage of fluid on syringing with the fluid felt in the throat. Functional success was defined in terms of relief from epiphora based on the subjective opinion and its categorization by Kraft and Crawford's grading and the fluorescein dye disappearance test (FDDT).
RESULTS: Eighty percent of eyes in canalicular trephination group and 73.3% of eyes in canaliculoDCR group were anatomically patent on syringing at the final follow-up. Sixty-six percent of eyes in trephination group and 53.3% in canaliculoDCR group were reported to have absent epiphora (complete recovery). Ten eyes in both groups had Grade 0 and 1 FDDT indicating a functional success of 66.6% in both groups.
CONCLUSIONS: Canalicular trephination can produce results comparable to canaliculoDCR with silicone intubation in cases of common canalicular blocks. The average duration of surgery is significantly less in canalicular trephination which gives this procedure an added advantage. Copyright:

Introduction

Canalicular obstructions can occur at any point along the course of the canaliculi and due to a wide variety of causes.[12345678] The spectrum of symptoms can be mild to severe. The minuscule diameter and the fragile nature of the canaliculi pose a major problem in the management of these blocks.[910111213] Repeated syringing and probing can itself aggravate the condition and further damage the canaliculi. Although canaliculodacryocystorhinostomy (canaliculoDCR) involving dissection and removal of obstruction in the common canaliculus with silicone intubation has been widely accepted as the procedure of choice, successful treatment of canalicular obstructions continues to represent a therapeutic challenge.[1415161718192021222324]

Sisler and Allarakhia in 1990 introduced the ophthalmic minitrephine to facilitate microtrephination of canalicular obstructions.[2526] They reported an anatomical success rate of 83.3% at 6-month follow-up. Ever since multiple studies have been done using this trephine for the management of canalicular stenosis with variable success [Table 1].

Table 1

Review of literature of previous studies on canalicular trephination

Author	Study	Year	Number of patients	Source	Results
Sisler and Allarkhia[25]	A new ophthalmic microtrephine	1990		Ophthalmic Surgery Journal	Introduction of a new instrument designed to facilitate microtrephination of tissues
Sisler and Allarkhia[26]	New microtrephines makes lacrimal canalicular rehabilitation an office procedure	1990	15	Ophthalmic Plastic and Reconstructive Surgery Journal	83.3% success rate by canalicular trephination at 6-month follow-up
Khoubian et al.[27]	Trephination and silicon stent intubation for the treatment of canalicular obstruction-effect of level of obstruction	2006	32	Ophthalmic Plastic and Reconstructive Surgery Journal	Distal monocanalicular obstructions have the highest degree (80%) of symptomatic epiphora relief, followed by distal bicanalicular (66%), common (59%), and proximal obstructions (55%) at 6 months
Lee and Choi[28]	The effectiveness of lacrimal trephination for the treatment of canalicular obstruction	2011	29 patients/38 eyes	Journal of Korean Ophthalmological Society	Anatomical success rate was 81.6%
Hussain et al.[29]	Use of Mini-Monoka stents for punctal/canalicular stenosis	2012	77 patients/123 eyes	British Journal of Ophthalmology	88% of cases had resolution of epiphora at 6-week follow-up
Nathoo et al.[30]	To evaluate efficacy of trephination for resolution of primary canalicular obstruction/obstruction secondary to failed DCR	2013	43 patients/45 eyes	Orbit	64% of patients avoided the morbidity of dacryocystorhinostomy
Zadeng et al.[31]	Role of lacrimal canalicular trephination and Mini-Monoka stent in the management of idiopathic distal canalicular obstructions: Our experience of 23 cases	2014	23	Asia Pacific Journal of Ophthalmology	Twenty eyes (83.33%) reported absent epiphora at 8-month follow-up
Present study	To compare the outcomes and efficacy of canalicular trephination with monocanalicular stenting and canaliculodacryocystorhinostomy with silicone intubation	2015-2016	30		Anatomical success of 80% and functional success of 66% was seen with canalicular trephination versus 73.3% anatomical success and 66% functional success in canaliculoDCR

DCR: Dacryocystorhinostomy

Our study intends to compare these two techniques and to come up with a better option between the two which can be used as the primary procedure of choice in cases of common canalicular blocks.

Materials and Methods

A total of 30 patients with common canalicular blocks were included and divided into two groups. Appropriate informed patient was taken and the study was approved by the Institute Ethics Committee. It was a prospective interventional comparative study. Patients were allocated in the groups by a series of random numbers. Group 1 included 15 patients who underwent canalicular trephination and monocanalicular silicone stent placement and Group 2 included 15 patients who underwent canaliculoDCR with bicanalicular silicone stent intubation. Detailed ophthalmic history was taken and eyelid and lacrimal system examinations were done for all the patients. Traumatic cases and those with nasolacrimal duct obstructions were excluded from the study. The diagnosis was confirmed by a preoperative syringing showing regurgitation of the fluid from the opposite punctum and inability to perceive the fluid in the throat and a soft stop appreciated on probing with a Bowman's probe. The tear meniscus height was measured by instilling fluorescein dye in the conjunctival cul de sac and measuring the height of tear film in the lower lid margin at the pupillary center using the reticule on the slit lamp biomicroscope. A fluorescein dye disappearance test (FDDT) and grading of epiphora based on the Kraft and Crawford scale [Table 2] were done.[3233]

Table 2

Kraft and Crawford grading of epiphora

Grading	Symptoms
Grade 0	No watering
Grade 1	Watering occurring only outdoors
Grade 2	Watering occurring indoors with some irritation
Grade 3	Constant epiphora

In canalicular trephination, local anesthesia was achieved by infiltration of a mixture of 50:50 of 2% lidocaine and 0.75% bupivacaine in the medial canthal area. Intraoperative syringing and probing was done and the location of the block in millimeters was noted. Then, the canalicular trephine [Figure 1] was introduced through the dilated punctum till the soft stop was felt. The stylet of the trephine was withdrawn and the trephine rotated in a clockwise and anticlockwise manner to allow its smooth progression till it removes the core of the obstructed canaliculus. The endpoint was when a hard stop was felt indicating removal of the obstruction. At this point, irrigation of fluid was done by a syringe attached to the hub of the trephine, and the patency of the passage was confirmed. The monocanalicular stent was then trimmed at its end into a bevel and gently passed through the system till its oval collarette head snugly fits into the punctum [Figure 2].

Figure 1

Canalicular minitrephine

Figure 2

(a) Punctal dilatation. (b) Canalicular trephination. (c) Onocanalicular stent insertion. (d) Advancement of the stent and insertion of collarette into the punctum. (e) Postoperative stent in place

The other group of patients who underwent canaliculoDCR had preoperative nasal packing and the procedure was done under local anesthesia using 2% lignocaine infiltration in medial canthal and ethmoidal area. A standard curvilinear medial canthal incision was given and soft tissue dissection was done. The periosteum was elevated and a bony ostium of the desired size was created. Anterior and posterior flaps of the lacrimal sac and nasal mucosa were created. The site of obstruction in canaliculus was identified by the insertion of a Bowman's probe and excised and a single silicone intubation tube was passed through both the canaliculi and left in place for 3 months. The anterior flaps of the sac and nasal mucosa were sutured with vicryl. The posterior flaps were excised. Soft tissue and skin were sutured and the ends of the silicone tubes were tied in a square knot in the nasal cavity.

After 3 months of follow-up, stents in both the groups were removed and syringing and FDDT was done for patency and the patients were followed up for 6 months.

Statistical analysis

All the data were documented in an Excel sheet and statistically analyzed using SPSS software at the end of the study. Qualitative data were expressed as percentages.

Groups having nonparametric data were subjected to Mann–Whitney test and to assess the changes in this group over a period of time, Wilcoxon signed-rank test was used.

Groups having parametric data were subjected to two-sample t-test and to see the changes in these groups over a period of time, paired t-test was used. P < 0.05 was deemed statistically significant.

Results

The mean age of the patients in canalicular trephination group was 41.06 ± 17.18 years and in canaliculoDCR with silicone intubation group was 48.8 ± 13.23 years. There were four (27%) males and 11 (73%) females in Group 1 and 6 (40%) males in and 9 (60%) females in Group 2. The mean duration of symptoms in canalicular trephination group was 10.13 ± 3.11 months and in canaliculoDCR was 10 ± 2.53 months. The mean location of the block from lower punctum was at 10 ± 0.84 mm in Group 1 and 9.86 ± 0.74 mm in Group 2.

The preoperative mean tear film height in the canalicular trephination and canaliculoDCR group was 0.96 ± 0.13 mm and 1.06 ± 0.17 mm, and after surgery, at final follow-up was 0.48 ± 0.25 mm (50% change; P = 0.002) and 0.59 ± 0.35 mm (44% change; P value = 0.002), respectively, with no significant difference between the two groups (P = 0.44).

The preoperative mean Schirmer's value in the canalicular trephination and canaliculoDCR group was 31.87 ± 2.5 mm and 31.53 ± 2.7 mm, and after surgery, at final follow-up was 18.6 ± 0.82 mm (43.5% change; P < 0.001) and 21.13 ± 1.73 mm (32.9% change; P < 0.001), respectively, with no significant difference between the two groups (P = 0.19).

In the canalicular trephination group, one patient had a premature stent extrusion at 1 month post surgery and at 3-month follow-up had restenosis. One patient in the same group did not have anatomical patency intraoperatively and remained the same at 3 months postoperative. Hence, a total of 13 patients were patent on syringing and probing at 3-month follow-up in canalicular trephination group. At postoperative follow-up of 4 months, restenosis had been noted in one patient and 12 patients were found to be patent and continued to be same at 6-month follow-up period. This anatomical success in the canalicular trephination group is statistically significant with P = 0.0005 (<0.05).

In the canaliculoDCR group, one patient had a premature stent extrusion at 2 months post surgery and at 3-month follow-up had restenosis. Hence, a total of 14 patients were patent on syringing and probing at 3 months post surgery. At postoperative follow-up of 4 months, restenosis was noted in three patients and 11 patients were found to be patent and continued to be the same at 6-month follow-up period. This anatomical success in the canaliculoDCR group is statistically significant with a P = 0.0009 (<0.05).

However, when we compared the anatomical patency outcomes at 3-month, 4-month, and 6-month follow-up post surgery between the two groups, P value at all these intervals was >0.9 (>0.05), implying that the two groups were comparable and that there was no statistically significant difference at each follow-up.

We evaluated the functional patency of the two procedures by an FDDT and a subjective relief from epiphora based on Kraft and Crawford grading system. Grading of FDDT was done 5 min after instillation of the dye, as given in Table 3.

Table 3

Grading of fluorescein dye disappearance test

Grading	Signs
Grade 0	All dye is cleared
Grade 1	Persistent thin marginal strip of dye
Grade 2	Persisting dye between Grade 1 and 3
Grade 3	Wide, brightly fluorescing tear strip

In the canalicular trephination group, preoperatively, six patients were in FDDT Grade 2 and nine were in Grade 3. At 6-month follow-up, we have noted three patients in Grade 0, seven in Grade 1, two in Grade 2, and three in Grade 3. This shifting of the subjects to Grade 0 and 1 at 6 months postoperative was found to be significant with P = 0.0016.

In the canaliculoDCR group, preoperatively, five patients were in FDDT Grade 2 and ten were in Grade 3. At 6-month follow-up, we have noted four patients in Grade 0, six in Grade 1, one in Grade 2, and four in Grade 3. This shifting of the subjects to Grade 0 and 1 at 6 months postoperative was found to be significant with P = 0.0016. However, between both the groups, the postoperative outcomes at 6 months were comparable and there was no statistically significant difference with P > 0.9.

The functional success based on the subjective relief from epiphora (Kraft and Crawford grading) was 66.6% (n = 10) with a significant P = 0.0016 in canalicular trephination group and 53.3% (n = 8) with a significant P = 0.0047 in the canaliculoDCR group at the final follow-up of 6 months. However, between both the groups, the results were comparable and there was no statistically significant difference with P = 0.7.

In the canalicular trephination group, at the end of 6-month follow-up, 80% of patients were fully satisfied and 20% were not satisfied. In the canaliculoDCR group, 73.3% were fully satisfied, 6.6% were partially satisfied, and 20% were not satisfied. However, between both the groups, the patient satisfaction at 6 months was comparable and there was no statistically significant difference with P > 0.90 (>0.05).

The mean duration of surgery was compared in the two groups. It was 23.13 ± 3.20 min in canalicular trephination group and 57.4 ± 8.01 min in the canaliculoDCR group and the difference is found to be statistically significant with P < 0.0001.

The results of the study are summarized in the table cited [Table 4].

Table 4

Summary of the results of the study

	Group 1 (canalicular trephination)	Group 2 (canaliculoDCR)
Total number of patients	15	15
Mean age (years)	41.06±17.18	48.8±13.23
Female: male	2.75:1	1.5:1
Mean duration of symptoms (months)	10.13±3.11	10±2.53
Location of block from lower punctum (mm)	9-5	9-5
	10-4	10-7
	11-5	11-3
Anatomical success (%)	80	73.3
Functional success - Fluorescein dye disappearance test (%)	66.6	66.6
Spontaneous tube extrusion	1 patient - 0.06%	1 patient - 0.06%
Mean duration of surgery (min)	23.13±3.20	57.4±8.01

DCR: Dacryocystorhinostomy

Discussion

Treatment of canalicular obstructions presents a challenge to the surgeon given the fragile and minuscule nature of the passages. Current treatment modalities advocate a canaliculoDCR as the primary procedure in obstructions involving the common canaliculus.[3435] Our study intends to compare this rather major surgical procedure with a relatively shorter procedure of canalicular trephination and monocanalicular stenting. The length of the common canaliculus varies around 3–5 mm and our study is concerned regarding the obstructions spanning this territory.

Both the groups were comparable with regard to age, sex, duration of symptoms, and other demographic data. After the surgery, both the groups were evaluated for various parameters, at previously defined intervals till 6 months. The main parameters studied were mean tear film height, Schirmer's test, anatomical patency on syringing and probing, subjective relief from epiphora, and FDDT. The quantitative results of our patients in both the groups were found to be comparable at all the time intervals during the study, although there was a significant intra-group difference between preoperative and postoperative final follow-up values in all the parameters evaluated in the study.

The preoperative mean tear film height and mean Schirmer's value in both the groups showed a significant decrease postoperatively which correlated well with the improvement of the symptoms in the respective subjects. Success at the final follow-up was defined both on anatomical and functional outcomes. Anatomical success was defined by the free passage of fluid on syringing with the fluid felt in the throat which was noted to be 80% percent in trephination group and 73.3% in canaliculoDCR group. Functional success was defined in terms of relief from epiphora based on the subjective opinion and its categorization by Kraft and Crawford's grading, and FDDT which was based on the amount of dye persisting at the end of 5 min of its instillation in the lower fornix.

Outcomes of our study correlated well with the previous study by Zadeng et al. who described canalicular trephination in 24 patients with common and distal canalicular blocks and reported an anatomical success of 91.67% and 83.33% of patients with absent epiphora indicating functional success at a minimum of 8-month follow-up.[31]

Our study also correlated with the initial study of Sisler and Allarakhia who introduced the minitrephine and performed the procedure in 15 patients with distal canalicular obstructions and achieved an anatomical success rate of 83.3% at 6-month follow-up.[2526]

Our results correlated well with the study done by Khoubian et al. in which trephination and silicone stent intubation were done for the treatment of canalicular obstructions.[27] They reported success rate based on the relief from epiphora and found that distal lower canalicular obstructions had the highest success rate (80% complete and 20% partial relief of epiphora) and proximal bicanalicular obstructions had the lowest success rate (55% partial relief and 45% no improvement).

Few complications occurred in our study. Premature spontaneous stent extrusion was noted in one patient at 1-month follow-up in canalicular trephination group and in one patient at 2-month follow-up in the canaliculoDCR group both of whom had restenosis at 3-month follow-up. Restenosis after stent and silicone tube removal in the respective groups was noted in one patient in canalicular trephination group and in three patients in the canaliculoDCR group at 4-month follow-up.

The surgical duration for canalicular trephination was significantly less when compared to canaliculoDCR. The morbidity and the need for excessive manipulation were less and there was no postoperative visible scar in trephination. Hence, we recommend trephination as a primary intervention of choice in cases of common canalicular blocks.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.