FP1789 : Rods or tubes, how effective is a new indigenous lacrimal intubation system

Dr.Santanu Mitra

Introduction:

Dacryocystorhinostomy (DCR) surgery makes a permanent opening from the lacrimal sac into the nasal space through which tears will drain freely. External Dacryocystorhinostomy (E-DCR) is still the gold standard in curing Primary Acquired Nasolacrimal Duct Obstruction (PANDO), with an average osteotomy size of15x15 mm¹. E-DCR currently has a very high success rate of 95-99%². Other approaches like Endonasal DCR (EN-DCR) with nasal endoscopes and laser assisted transcanalicular DCR (TC-DCR) also report good success rates. Most reports demonstrated no significant difference between the success rates of primary E-DCR irrespective of silicone intubation³(Feng et al).

DCR by any approach described a failure rate between 1-20%⁴, primary causes being (a) common canalicular obstruction, (b) membranous obstruction of the bony ostium, and rarely, (c) failure to open the lacrimal sac properly.

We believe there are specific Indications for temporary silicone intubation in DCR surgeries with better outcomes, like:

• Patients with canalicular problems, like distal or common canalicular obstructions
• Intraoperative damaged sac or nasal mucosal flaps
• Revision DCR surgeries

Silicone tube intubation in lacrimal duct surgery was introduced by Gibbs in 1967⁵. Presently silicone intubation systems can be monocanalicular or bicanalicular. This study deals with the bicanalicular system only. The conventional one consists of silicone tubes with the open ends fitted with malleable metallic probes (bodkin). The modified one is made out of silicone rods fitted with needles, used for frontalis sling surgery in ptosis correction.

Purpose:To evaluate the technique, efficacy, and cost effectiveness of an indigenously modified lacrimal intubation system.

Study Design:Retrospective, comparative, interventional case series.

Methods:Consecutive 140 E-DCR surgeries requiring intubation between 2012 and 2016 were selected. All surgeries performed by the author. Patients were then randomly divided into 2 groups, Group A (65 cases) received conventional silicone intubation system, and Group B (75 cases) received the modified silicone rod intubation.

A complete pre-operative ophthalmological checkup of all patients were performed. The lacrimal drainage system was investigated with Dye disappearance test (DDT), Syringing, Probing and Nasal endoscopy.

Hospital Ethical committee approval and proper consent from the patients were obtained.

15 cases were Primary E-DCR where intraoperative damage required intubation. 125 cases were revision procedures, where TC-DCR was chosen in 18 cases with a free common canalicular system, rest 107 had repeat external approach. Overall female to male ratio was 102:38, age ranging from 19 to 68 years (Table 1). All surgeries performed under local anaesthesia. E-DCR surgeries were performed routinely. The causes of failure of the primary surgery were looked for, mostly it was an obstruction at the distal end of common canaliculus. Once the obstruction was removed a bicanalicular intubation was performed with tubes or rods. Free ends of the tubes were knotted and put inside the nose. The free ends of the rods were passed through the silicone sleeve, knotted against it and put inside the nose.

Conventional intubation was done with commercially available bicanalicular silicone tube system designed as the original Crawford Lacrimal Intubation set (Fig 1, Auro Lac: No financial interest). The modified intubation system was made out of the frontalis sling suspension silicone rod system (Fig 2, Aurosling: No financial interest) used in ptosis correction surgery. The two needles fitted at the two ends of the rod were cut with pliers to an approximate length of 20-22 mm, the sharp ends were made blunt. The whole system was then resterilised.

Postoperatively patients were seen at 1 week, 6 weeks, 12 weeks, then 3 monthly up to 1 year. Intubation system removed at 12 weeks, 2 cases excluded from the study who lost the tubes earlier. Dye disappearance test and nasal endoscopy performed in all post-operative visits, syringing and probing done after intubation removal.

The patients were followed up for a minimum period of 12 months.

Result:

There was afemale preponderance, 38 males and 102 females. Primary cases (15) received intubation randomly when there was an intraoperative damage to the lacrimal sac flap or nasal mucosa, or both. Failed cases (125) were randomly intubated with silicone tube or rod systems.

Table 1: (Patient profile)

N = 140	Gr A: with tubes N1 = 65	Gr B: with rods N2 = 75
Age range (yrs)	19 – 65	20 – 68
Male: Female	23:55	15:47
Primary E-DCR	07	08
Revision E-DCR	50	57
TC DCR with Lasers	08	10

Anatomical patency tested with syringing following the removal of the intubation system showed a patent nasolacrimal passage in 123 cases (87.85%), 55 in Gr A (84.61%), and 68 in Gr B (90.66%). The difference was not statistically significant between the two groups. Dye disappearance test was negative in 32 cases (22.85%), 18 in Gr A and 14 in Gr B, not statistically significant again.

Mean surgical time with conventional intubation system was longer than that with the modified system, and the difference was statistically significant (Table 2).

Table 2:

N = 140	Group A N1 = 65	Group B N2 = 75	Remarks
Mean Surgical Time  (in minutes)	38±4.6	15±2.5	p <0.001
Overall Failure Rate (Not patent on syringing): 12.14% (17 cases)
Anatomical Failure Rate	10(15.38%)	7(9.33%)	p = 0.5
Evaluation results: Symptomatic with DDT  -ve	18 (27.69%)	14 (18.66%)	Statistically not significant

Fibrosis or membranous obstruction of the common canaliculus was found to be the major cause of failure of the primary surgery (about 90% cases). Average surgery time was significantly much longer with the conventional intubation system. Primary reason was the difficulty in negotiating the much longer metallic probes through the narrow surgical field, and the irritating problem of the tubes getting dislodged from the probes, particularly while passing through the punctal juncture. You have to relodge the tube onto the metal probe.

Minor complications with lacrimal intubation surgery like, punctal tears, conjunctival irritation, granulation tissue formation around the tube inside the nose, etc. were common to both groups. 2 cases showing no tube at 1 week postoperative follow up were excluded from the study.

Discussion:

External DCR has been the gold standard in acquired nasolacrimal duct obstruction distal to common canaliculus. Higher success rate with lacrimal intubation in primary DCR surgery has not been established (A meta-analytical study by Feng, Y. F. et al in 2011)³. There are reports supporting a better outcome of intubation in revision DCR surgeries⁶. This study included revision surgeries primarily, and few primary cases with intraoperative complications. We followed the techniques of Dutemps and Bourguet with suturing of modified anterior flaps only made out of muscle layer.

The modified intubation system used in this study was based on the O’Donoghuebicanalicular stent design. It has a probe length of 2-2.2 cm compared to 11 cm of the conventional system. The solid silicone rod has a larger diameter of 0.9 mm compared to 0.64 mm. The reduced probe length allowed easy maneuverability within the small surgical field. Larger diameter and solid rod provided better stenting effect. The solid rod system had no risk of tube slipping out of the probe. Intranasal fixation with the sleeve system in the modified one was faster and easier. The silicone rod was stout enough to negotiate through the canaliculus even without the metal probe, so could be resterilised, and used in multiple cases. Overall, intubation with the modified silicone rod was technically easier and faster, also safe and economical.

The study was retrospective in nature, with single surgeon and unicentric data. These were the study limitations.

Conclusion:

The modified lacrimal intubation system with silicone rods do not produce a higher success rate than the conventional silicone tube systems. But it is relatively easier to perform, reduces the surgical time significantly, does not lead to any serious complication, and also economically viable. So it can be a good alternative to the commonly available intubation systems.

Fig 1.Auro-Lac

Fig 2.Aurosling

References:

1.Levine MR. Dacryocystorhinostomy. In: Levine MR, ed. Manual of Oculoplastic Surgery. 2nd ed. Boston, Mass: Butterworth-Heinemann; 1996:37-45

2.Welham RAN, Wulc AE. Management of unsuccessful lacrimal surgery. 1987; 71:152

3.Shagufta et al. External dacryocystorhinostomy with and without silicone tube intubation in chronic dacryocystitis with nasolacrimal duct block. JK Science. 2013; 15(1)

4.Feng YF, Cai JQ, Zhang JY, & Han XH. A meta-analysis of primary dacryocystorhinostomy with and without silicone intubation. Can. J. Ophthalmol. 2011; 46: 521-7

5.Gibbs DC. New probe for intubation of lacrimal canaliculi with silicone tubing. Br J Ophthalmol. 1967; 51:198

6.DeAngelis D, Hurwitz J, Shinoff M. Lacrimal drainage system stenting with silicone tubing. OphthalPlastReconsttr Surg. 2000; 16(4): 305-6

	E-DCR (n=57)	TC-DCR (n=72)
Objective •        Patent on irrigation •        FETT •        Range •        Mean	52 (91.22%)        39  13.2 sec – 1.45 min         38.88 sec	62 (86.11%)        46  21sec – 2.50min 1.14.69min
Subjective •        Asymptomatic •        Marked improvement •        Unchanged/ symptomatic •        Worse	08 34 05          05	06 21 35 10

 Objective and Subjective Results:

Table 2

	E-DCR (n=57)	TC-DCR (n=72)
FETT  mean	38.38 sec	1.14.69 min
FETT  mean < 1 min	28/39 (71.79%)	14/46 (30.43%)
FETT  mean > 1 min	11/39 (28.2%)	32/46 (69.56%)

Functional Endoscopic

Transit Time (FETT):

Table 3 

Though anatomically patent, a slower dye transit time indicates more ‘watery eyes’ as evidenced from higher numbers of symptomatic cases in TC-DCR group.

Complications:Narrow ostium, synechae and granulation tissue at ostium, soft tissue membrane formation are the various complications noted.

Study Limitations: Prospective study, insufficient number of cases and follow up.No masking done,

so possibility of inherent bias. No proper control study done with normal subjects. The study was

not age and gender matched.

Discussion:

FTT provides a quantitative measure of lacrimal drainage function after DCR surgery. ⁴A successful DCR surgery means anatomical patency, functional drainage and no symptom of epiphora.

Jones’ primary dye test evaluates the functional ability of the normal nasolacrimal passage and the F
EDT test is based on that principle. FEDT was extremely useful for understanding rhinostomy

function after DCR⁵.

FETT tries to correlate the functional success with symptoms in post DCR patients

Functional Transit Time of ≤45 sec. has a statistically significant association with subjective success ⁶.

There is no correlation between the success of DCR surgery with  a large intraoperative ostium⁷.

Conclusion:

• There is no statistical significant difference between the anatomical patency of E-DCR and TC-DCR groups
•  Functional success rate is significantly higher in the E-DCR cases
•  Dye transit time more than 1 min. is associated with larger number of symptomatic ‘watery eyes’ in the TC-DCR group
•  The rhinostomy size between the two groups 3 months after operation shows no significant difference

Referrences:

1. Levine MR. Dacryocystorhinostomy. In: Levine MR, ed. Manual of Oculoplastic Surgery. 2nd ed. Boston, Mass: Butterworth-Heinemann; 1996:37-45.

2. BrigitaDrnovšek-Olup and Matej Beltram. Transcanaliculardiode laser-assisted dacryocystorhinostomy. Indian J 2010 ;58:213–17.
3. Moore WM, Bentley CR, Olver JM. Functional and anatomic results after two types of endoscopic endonasal dacryocystorhinostomy: Surgical and holmium laser. 2002;109:1575–82.
4. Delaney Yvonne M, Khooshabeh Ramona.Fluorescein transit test time and symptomatic outcomes after external dacryocystorhinostomy. Ophthalmic plastic and reconstructive surgery 2002;(18):281-84
5. Linberg JV, Anderson RL, Bumsted RM, Barreras R. Study of intranasal ostium external dacryocystorhinostomy. Arch Ophthalmol. 1982;100:1758–62.
6. Ezra E, Restori M, Mannor GE, Rose GE. Ultrasonic assessment of rhinostomy size following external dacryocystorhinostomy. Br J Ophthalmol.1998;82:786-789.
7. Yazici B, Yazici Z. Final nasolacrimal ostium after external dacrycystorhinostomy. Arch Ophthalmol. 2003;121:76–80