The Dry Eye Zone

Rebecca's Blog


Study: Measuring symptoms after DCR surgery... and ruminations on the meaning of safety and efficacy

Am J Rhinol Allergy. 2018 Jan 1;32(1):46-51. doi: 10.2500/ajra.2018.32.4494.
Comparison between endoscopic and external dacryocystorhinostomy by using the Lacrimal Symptom Questionnaire: A pilot study.
Wong WK, Dean S, Nair S.

Preface: What's a DCR and who among my readers would care?

Excess tears drain through ducts in the corners of your eyes through your canaliculus, lacrimal sac and nasolacrimal duct into your nasal passage. For some people these draining canals can get blocked and sometimes a surgery called a DCR is performed. A DCR is not about clearing the blockage per se, but rather creating a bypass. It can be done externally (incision through the nose!) or endoscopically.

The reason DCRs are sometimes relevant to the dry eye crowd is that dry eye patients are often treated with plugs, and permanent silicone or thermoplastic plugs (such as SmartPlugs) have a nasty way of traveling to places where they cannot be found, and then festering and causing problems. Once plugs "get inside" somewhere - anywhere - they cannot be seen with imaging, so sometimes the only way to solve that kind of problem is to basically cut it open and find it... hence the DCR. 

I've known an awful lot of people over the years who had plug complications. Oculoplastic surgeons tend to have a lot of horror stories to share about bits of plastic or silicone floating around in that lacrimal sac and re-appearing years later. I almost had to have a DCR myself a few years back due to a misbehaving SmartPlug that resurfaced (we believe) after more than a decade and rendered me miserable for about a year. I had a canaliculotomy first, and we didn't find the plug, but then the problem thankfully resolved itself before I went ahead with a DCR.

Safety vs efficacy, in endoscopic vs external DCR... and in medicine in general.

I remember vividly when I had to consider which type of DCR to get, at the time I was planning to go for it. It was a hard call. Usually they are compared in terms of "safety and efficacy", the standard measures of all things medical, from drugs to surgical interventions - that is, are there complications, and how well does it work according to the standard established.

Unfortunately the questions both of safety and of efficacy too often leave out how either of those things are measured by the patients themselves.

Safety standards may be acceptable to physicians because the side effects may be deemed to be so minor by the physicians... but minor to the physician does not always mean minor to the patient. Those of us with vision quality problems or dry eye symptoms after LASIK can readily attest to that, I'm sure. 

Likewise, efficacy may be assessed differently by doctors versus patients. It all depends on your point of view and which problem you're trying to solve. The problem the doctor's trying to solve, in this case, tear drainage, may not entirely overlap with the problem or problems the patient's trying to solve, which is why I appreciated this DCR study so much.

In this study: Compare results by SYMPTOMS and quality of life

These are the things that always make me sit up and read more carefully - when I see studies focusing on the outcome as measured by the patients themselves. 

In this study, they employed a Lacrimal Symptom Questionnaire before and after surgery, comparing the two surgical approaches. The questionnaire has just a few questions to gauge (1) social and lifestyle impact of the tear duct problem and (2) a scorecard for the type and extent of problems experienced with each eye, from watering to pain to stickiness to swelling. Both types of surgery showed significant improvements, though it looks like the endonasal group won. I'm not a subscriber to the journal so I haven't seen the complete results to be able to report back on nuances that might be important - I just liked that someone is focusing on quality of life impact from the surgery afterwards.

Epiphora has a significant impact on the patient's quality of life and is commonly caused by nasolacrimal duct obstruction. Dacryocystorhinostomy (DCR) has traditionally been performed via an external approach, which involves a skin incision. With the advent of endoscopes, the endonasal approach to DCR has gained significant popularity.
To prospectively compare the quality of life of adult patients who underwent either an endonasal or an external DCR for acquired nasolacrimal duct obstruction, the Lacrimal Symptom Questionnaire (Lac-Q) was administered before and after surgery. The treatment group assignment was nonrandom and performed based on patient preference. The Lac-Q is a validated questionnaire that assesses the subjective perception of one's well-being from an eye-specific symptom and social impact standpoint. Total scores range from 0 (no concerns) to 33 (maximal degree of ocular symptoms and social impact).
Sixty patients (22 in the endonasal group, 38 in the external group) were recruited between January 1, 2014, and January 1, 2016. Postoperative assessment was performed at 3 and 6 months. Patients who underwent external DCR reported a median 7.0-point improvement (interquartile range [IQR], 3.0-11.0) in total Lac-Q scores. A 12.0-point improvement (IQR, 10.0-18.5) was seen in the endonasal group (p = 0.005). The median change in the social impact score was 3.0 and 4.0 in the external group and the endoscopic group, respectively (p = 0.029). Changes in the median lacrimal symptom score were 4.0 in the external group and 8.0 in the endoscopic group (p = 0.014). The anatomic patency rate was lower in the external group (60.0%) when compared with the endonasal group (90.4%). Patients in the external DCR group were significantly older (median age, 51 versus 41 years).
Our study indicated that both endonasal and external DCR can lead to improvement in quality of life by using a validated questionnaire. Although there are differences in age and anatomic success rates between the two groups, subgroup analyses indicated that the differences in the Lac-Q scores persisted when age and anatomic patency were removed as potential confounding factors. Further larger, randomized studies would be helpful.