Evaluation of Patients for Endoscopic DCR: Sac Syringing and Radionuclide Scintigraphy

Abstract

To evaluate the importance of sac syringing and radionuclide scintigraphy for pre operative work up of patients with epiphora. In this study, from the year Jan. 2013 to Jan. 2016, patients of epiphora were subjected to radionuclide scintigraphy of lacrimal apparatus in addition to sac syringing and probing. The significance of adding radionuclide scintigraphy in pre op assessment of epiphora was statistically assessed. 146 lacrimal systems were enrolled in the study. Out of them, 89 were males and 57 were females. The mean age of the patients was 42 years. Of the 146 lacrimal systems evaluated, scintigraphy detected 25 cases of common canalicular block versus 8 cases by sac syringing. Also radionuclide scintigraphy was able to detect 11 cases of functional obstruction which were patent on syringing. Results were analysed statistically. Correct diagnosis of site of obstruction is essential to predict a better surgical outcome of endoscopic DCR as it is a highly successful surgical procedure which can be done in distal NLDO only. We recommend that all patients of epiphora should undergo sac syringing as an initial test. This is a simple, inexpensive procedure which can be done as an OPD procedure in a short time. However, radionuclide scintigraphy can be added as an additional investigation to more accurately delineate site of block. It is an objective test and delineates the lacrimal system both anatomically and functionally. Also it diagnoses functional block which appears patent on syringing.

Introduction

Endoscopic DCR is a less time consuming, more cosmetic and a highly successful tool in the armamentarium of otolaryngologists for treating distal nasolacrimal drainage obstruction (NLDO). This surgery has gained popularity over the years as an attractive option to conventional external DCR. However, to improve the success rates of endoscopic DCR it is essential to diagnose the site of obstruction accurately as only distal NLDO can be addressed by this surgery [1]. The proximal NLDO would require external DCR/other measures.

For better pre op evaluation and to improve outcome of surgery, newer techniques are being increasingly employed in the pre op investigations. Numerous diagnostic tests are available for epiphora. These include non invasive tests like saccharin test, fluorescein dye test, Jones I test, radionuclide scintigraphy and invasive tests like contrast dacryocystogram [2, 3].

However, there is a lack of standardisation and various specialists asking for different investigations. There is a need to develop a protocol of pre op investigations, so that maximum patients can benefit from surgery. Moreover, patients of common canalicular block who will not benefit from endoscopic DCR should be identified accurately. Improved diagnosis would give better post operative results. This would entail tests which would be accurate, more objective and efficient so that maximum patients can benefit from the surgery.

Also, there is a subset of patients with functional nasal obstruction in whom there exists a physiological block in the nasolacrimal duct system [4]. These systems are patent on syringing and there is no standard test to diagnose these cases. Syringing is an anatomic test and a more physiological test is likely to detect functional obstruction.

In our study we have used radionuclide scanning in addition to sac syringing to pre operatively assess the lacrimal passages. A better preoperative assessment would in turn predict better post operative outcomes for larger number of patients. Though various authors have studied the investigation modalities in diagnosis of epiphora in detail, we have tried to statistically assess the significance of adding radionuclide scintigraphy in pre op assessment of epiphora.

Materials and Methods

146 patients with complaints of epiphora who presented to our hospital for evaluation from Jan. 2013 to Jan. 2016 were included in the study. Informed consent was obtained from all individual participants included in the study. Patients were routinely examined and underwent detailed clinical history taking. All patients without any obvious abnormality of the eyelids and lacrimal puncta were evaluated by sac syringing and radionuclide scintigraphy. Patients with nasal polyposis, trauma and revision surgery, were excluded from the study. The charts of patients in the study population were evaluated for demographic data (Fig. 1).

Fig. 1.

Radionuclide scintigraphy images

Sac syringing was done in the ENT OPD by an otorhinolaryngologist. Radionuclide scintigraphy was done with patient placed in modified sitting position so that the head rests on a modified slit lamp support that includes a chin rest, forehead support, and straps to immobilize the head for the study. Just before the instillation of radionuclide, manual pressure over the inner canthus empties the lacrimal sacs. With the head tilted back, 100 mic Ci of 99m Tc-sulphur colloid is placed in the lateral conjunctival sac using a micropipette. Static anterior images were acquired at 5, 10, 30 min.

Results and Analysis

From the year Jan. 2013 to Jan. 2016, 146 lacrimal systems were enrolled in the study. Out of them, 89 were males (60.9% with mean age of 43 ± 7.42 years; range 18–54 years) and 57 were females (39.1% with mean age of 40 ± 5.42 years; range 20–46 years) (M:F 1.56:1). The mean age of the patients was 42.12 ± 7.66 years (range 18–54 years).

Of the 146 lacrimal systems evaluated, scintigraphy detected 25 cases of common canalicular block versus 8 cases by sac syringing. Also radionuclide scintigraphy was able to detect 11 cases of functional obstruction which were patent on syringing. The results of sac syringing versus radionuclide scintigraphy is detailed at Table 1.

Table 1.

Results of sac syringing versus radionuclide scintigraphy

	Sac syringing	Radionuclide scintigraphy
Distal nasolacrimal drainage obstruction	127	108
Common canalicular block	08	25
Functional block	Nil	11
Patent	11	02

The results were statistically analysed using Mc Nemar test and p value was found to be less than 0.05 which was statistically significant (p < 0.001).

Discussion

Patients of epiphora who have distal NLDO can be surgically treated with endoscopic DCR. Also, functional nasolacrimal duct obstruction can be treated with endoscopic DCR [5]. The advantages of endoscopic DCR are that it can be done both under local and general anaesthesia unlike external DCR which is done only under general anaesthesia. The conventional external DCR for distal NLDO leaves an external scar and interferes with the pump mechanism of the orbicularis oculi muscle. Hence endoscopic DCR which is more cosmetic, less time consuming and a highly successful procedure is an attractive alternative for these patients. The success rate is 82–95% [6].

Accurate prediction of site of block is essential preoperatively to decide whether patient can be offered endoscopic DCR. Sac syringing has traditionally been used as a test to diagnose distal NLDO. It is used in pre operative evaluation to plan endoscopic DCR. This is quick, cheap and can be done as a OPD procedure. However the results are observer based. Also this technique cannot diagnose a functional block of the lacrimal passages. Practically though, if a patient of epiphora has a nasolacrimal system patent on syringing, he would be having a functional block.

Dacryocystography and Contrast Dacryocystography give an excellent anatomical study of the nasolacrimal passage [7]. However it requires ophthalmic assistance for instillation of dye and causes discomfort to the patient. There is radiation exposure to the patient. Also, it does not give physiological information [8, 9]. This is because the contrast injection under pressure overcomes the functional obstruction.

Dacryoscintigraphy was described by Rossomondo et al. [10]. With advances in imaging techniques, the radionuclide scintigraphy is increasingly being used in pre operative evaluation of the lacrimal apparatus [11–13]. This procedure is more objective and non invasive [14–16]. Also it can assess functional blockage [17, 18]. However this examination is a costly alternative, requires the services of a nuclear medicine specialist and involves radiation exposure to the patient.

Our study shows that sac syringing combined with radionuclide scintigraphy gives the best results. Though the conventional sac syringing is effective, its success rate when used alone is less, as compared to combining it radionuclide scintigraphy. Sac syringing, as it is observer based, may not accurately diagnose the site in all cases. Also a functional block would be patent on syringing.

Conclusion

There is no uniformity in tests used for preoperative evaluation of epiphora. Accurate detection of site of obstruction is essential to plan surgery. Endoscopic DCR is a highly successful surgical procedure which can be done in distal NLDO only. Hence, correct diagnosis of site of obstruction is essential to predict a better surgical outcome of endoscopic DCR. We recommend that all patients of epiphora should undergo sac syringing as an initial test. This is a simple, inexpensive procedure which can be done as an OPD procedure in a short time. However, as it is observer based, radionuclide scintigraphy can be added as an additional investigation in patients being considered for endoscopic DCR to more accurately delineate site of block. It is an objective test and delineates the lacrimal system both anatomically and functionally. It gives a better diagnostic information about common canalicular block which may be missed on sac syringing. Also it diagnoses functional block which appears patent on syringing.

Compliance with Ethical Standards

Conflicts of interest

The authors declare that they have no conflict of interest.

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed Consent

Taken by all participants of study.