Background
A dacryocystorhinostomy (DCR) procedure aims to restore drainage of tears by bypassing a blockage in the nasolacrimal duct, through the creation of a bony ostium that allows communication between the lacrimal sac and the nasal cavity. It can be performed using endonasal or external approaches. The comparative success rates of these two approaches have not yet been established and this review aims to evaluate the relevant up-to-date research.

Objectives
The primary aim of this review is to compare the success rates of endonasal DCR with that of external DCR. The secondary aim is to compare the complication rates between the two procedures.

Search methods
We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2016, Issue 8), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to 22 August 2016), Embase (January 1980 to 22 August 2016), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to 22 August 2016), Web of Science Conference Proceedings Citation Index- Science (CPCI-S) (January 1990 to 22 August 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 22 August 2016. We requested or examined relevant conference proceedings for appropriate trials.

Selection criteria
We included all randomised controlled trials (RCTs) comparing endonasal and external DCRs.

Data collection and analysis
Two review authors independently assessed studies for eligibility and extracted data on reported outcomes. We attempted to contact investigators to clarify the methodological quality of the studies. We graded the certainty of the evidence using GRADE.

Main results
We included two trials in this review. One trial from Finland compared laser-assisted endonasal DCR with external DCR, and one trial from India compared mechanical endonasal DCR (using punch forceps) with external DCR. The trials were poorly reported and it was difficult to judge the extent to which bias had been avoided.

Anatomic success was defined as the demonstration of a patent lacrimal passage on syringing, or endoscopic visualisation of fluorescein dye at the nasal opening of the anastomoses after a period of at least six months following surgery. Subjective success was defined as the resolution of symptoms of watering following surgery after a period of at least six months. Both included trials used anatomic patency demonstrated by irrigation as a measure of anatomic success. Different effects were seen in these two trials (I2 = 76%). People receiving laser-assisted endonasal DCR were less likely to have a successful operation compared with external DCR (63% versus 91%; risk ratio (RR) 0.69, 95% confidence intervals (CI) 0.52 to 0.92; 64 participants). There was little or no difference in success comparing mechanical endonasal DCR and external DCR (90% in both groups; RR 1.00, CI 0.81 to 1.23; 40 participants). We judged this evidence on success to be very low-certainty, downgrading for risk of bias, imprecision and inconsistency. The trial from Finland also assessed subjective improvement in symptoms following surgery. Resolution of symptoms of watering in outdoor conditions was reported by 84% of the participants in the external DCR group and 59% of those in the laser-assisted endonasal DCR group (RR 0.70, CI 0.51 to 0.97; 64 participants, low-certainty evidence).

There were no cases of intraoperative bleeding in any participant in the trial that compared laser-assisted endonasal DCR to external DCR. This was in contrast to the trial comparing mechanical endonasal DCR to external DCR in which 45% of participants in both groups experienced intraoperative bleeding (RR 1.00, 95% CI 0.50 to 1.98; 40 participants). We judged this evidence on intraoperative bleeding to be very low-certainty, downgrading for risk of bias, imprecision and inconsistency.

There were only two cases of postoperative bleeding, both in the external DCR group (RR 0.33, 95% CI 0.04 to 3.10; participants = 104; studies = 2). There were only two cases of wound infection/gaping, again both in the external DCR group (RR 0.20, CI 0.01 to 3.92; participants = 40; studies = 1). We judged this evidence on complications to be very low-certainty, downgrading one level for risk of bias and two levels for imprecision due to the very low number of cases.

Authors' conclusions
There is uncertainty as to the relative effects of endonasal and external DCR. Differences in effect seen in the two trials included in this review may be due to variations in the endonasal technique, but may also be due to other differences between the trials. Future larger RCTs are required to further assess the success and complication rates of endonasal and external DCR. Different techniques of endonasal DCR should also be assessed, as the choice of endonasal technique can influence the outcome. Strict outcome criteria should be adopted to assess functional and anatomical outcomes with a minimal follow-up of six months.

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Endonasal versus external dacryocystorhinostomy for nasolacrimal duct obstruction

BACKGROUND The aim of this study was to assess the etiological factors contributing to the failure of a dacryocystorhinostomy (DCR). PATIENTS AND METHODS Retrospective review was performed in 100 consecutive patients who were diagnosed with anatomically failed DCR at presentation to a tertiary care hospital over a 5-year period from 2010 to 2015. Patient records were reviewed for demographic data, type of past surgery, preoperative endoscopic findings, previous use of adjuvants such as intubation and mitomycin C, and intraoperative notes during the re-revision. The potential etiological factors for failure were noted. RESULTS Of the 100 patients with failed DCRs, the primary surgery was an external DCR in 73 and endoscopic DCR in 27 patients. Six patients in each group had multiple revisions. The mean ages at presentation in the external and endoscopic groups were 39.41 years and 37.19 years, respectively. All patients presented with epiphora. The most common causes of failure were inadequate osteotomy (69.8% in the external group and 85.1% in the endoscopic group, P=0.19) followed by inadequate or inappropriate sac marsupialization (60.2% in the external group and 77.7% in the endoscopic group, P=0.16) and cicatricial closure of the ostium (50.6% in the external group and 55.5% in the endoscopic group, P=0.83). The least common causes such as ostium granulomas and paradoxical middle turbinate (1.37%, n=1) were noted in the external group only. CONCLUSION Inadequate osteotomy, incomplete sac marsupialization, and cicatricial closure of the ostium were the most common causes of failure and did not significantly differ in the external and endoscopic groups. Meticulous evaluation to identify causative factors for failure and addressing them are crucial for subsequent successful outcomes.

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Etiologic analysis of 100 anatomically failed dacryocystorhinostomies.

Purpose To provide a systematic review of the literature on the etiopathogenesis of primary acquired nasolacrimal duct obstruction (PANDO). Methods The authors performed a PubMed search of all articles published in English with specific reference to etiopathogenesis of PANDO or associations of PANDO. Data captured include demographics, study techniques, hypothesis, presumed or confirmed interpretations with regards to pathogenesis, mechanisms, or pathways. Specific emphasis was laid on addressing the lacunae and potential directions for future research. Results Numerous factors are believed to contribute to the etiopathogenesis of PANDO. The basic pathogenesis involves inflammation, vascular congestion, mucosal edema, fibrosis, obstruction, and stasis. Bony nasolacrimal duct diameter does not appear to play a significant role. There is no convincing data to substantiate nose as the site of disease origin and nasal factors appear to be comorbidities. Hormonal mechanisms are more evidence-based but can only partly explain the pathogenesis. Vascular theories are based on the behavior of perilacrimal cavernous bodies, their autonomic control, and additional structural changes in the helical patterns of connective tissue fiber arrangements. Repeated vascular malfunction leading to structural epithelial and subepithelial changes currently appears to be the most evidence-based and accepted theory. Tear proteomics holds a promise in decoding the etiopathogenesis of PANDO, at least in part. Conclusions The etiopathogenesis of PANDO appears to be multifactorial. Hormonal microenvironments, vascular factors, and tear proteomics are promising candidates for further work. There is a need for focused work by Clinician-Scientists and the answers can have far reaching clinical implications.

Etiopathogenesis of Primary Acquired Nasolacrimal Duct Obstruction: What We Know and What We Need to Know.

Endonasal dacryocystorhinostomy (DCR) is a well-established treatment method in patients with nasolacrimal duct obstruction. However, there are a few reports about the overall management of failed endonasal DCR. We investigated the causes and management strategies of failed endonasal DCR.

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Cause and Management of Patients With Failed Endonasal Dacryocystorhinostomy.

Purpose: To describe the occurrence of community-onset methicillin-resistant Staphylococcus aureus (MRSA) infections of the lacrimal system and their treatment. Methods: This cases series consisted of data obtained from seven clinical cases of acute or subacute MRSA dacryocystitis, with or without concurrent conjunctivitis, occurring in nonhospitalized individuals presenting between December 2001 and July 2003. Clinical presentations, microbial culture results, treatment modalities, and outcomes were retrospectively reviewed. Results: Three patients were successfully treated with antibiotics and lacrimal surgery with no recurrence of symptoms after surgery for 6 months or longer. Four patients had temporary relief of symptoms with antibiotic therapy, but surgery was not performed for nonophthalmologic reasons, and recurrence occurred. Conclusions: The treatment of MRSA dacryocystitis can be challenging. Microbiologic cultures should be performed in all patients with dacryocystitis that is unresponsive to conventional first-line antibiotic treatment and in patients at risk for acquisition of MRSA. Appropriate antibiotic therapy in combination with dacryocystorhinostomy appears to be the optimal treatment.

Dacryocystitis caused by community–onset methicillin–resistant Staphylococcus aureus.

PURPOSE To analyze the clinical outcomes of external (EX-), endoscopic (EN-), and transcanalicular multidiode laser (TC-) with dacryocystorhinostomy (DCR). METHODS Ninety-two patients with primary acquired nasolacrimal duct obstruction were enrolled (divided into EX-DCR [n = 33], EN-DCR [n = 30], and TC-DCR groups [n = 29]) in this prospective study. Primary outcome measures were the anatomical and functional success of operations at the last control examination. Secondary outcome measures were the ostium size, surgical time, and complications. RESULTS The difference in mean surgical time among the 3 groups was statistically significant (p < 0.0001). External DCR required the longest surgical time (46.6 ± 15.3 minutes), while TC-DCR was the shortest (20.3 ± 7.7 minutes). There were no significant differences between the groups regarding anatomical (81.8%, 75.9%, and 76.7% in EX-, EN-, and TC-DCR groups, respectively; p = 0.824) and functional success rates (81.8%, 72.4%, and 73.3% in EX-, EN-, and TC-DCR groups, respectively; p = 0.626). Final ostium size was the largest with EX-DCR (33.7 ± 17.4 mm) and smallest with EN-DCR (19.0 ± 8.9 mm; p = 0.001). The complication rate was similar in all groups. The most common complications were the formation of granulation tissue (16.3%) and intranasal synechiae (9.8%), all of which led to surgical failure and were more frequent in the EN- and TC-DCR groups. CONCLUSIONS External DCR, EN-DCR, and TC-DCR had similar success and complication rates in patients with primary acquired nasolacrimal duct obstruction. External DCR resulted in the largest ostium size. Transcanalicular DCR appeared to be effective with the shortest surgical time.

Prospective comparison of 3 dacryocystorhinostomy surgeries: external versus endoscopic versus transcanalicular multidiode laser.

Purpose: To compare the conjunctival, lacrimal sac, and nasal flora cultures and conjunctival normalization time following external (EX-), endoscopic (EN-), and transcanalicular multidiode laser (TC-) dacryocystorhinostomy (DCR) and to evaluate the relationship between culture positivity and surgical success. We further performed antibiotic sensitivity analyses for lacrimal sac culture samples. Methods: A total of 90 patients with primary acquired nasolacrimal duct obstruction were recruited and divided into EX-DCR (n=32), EN-DCR (n=28), and TC-DCR (n=30) groups. Conjunctival, nasal, and lacrimal sac cultures and antibiograms were analyzed. Results: In all three groups, coagulase-negative Staphylococcus (CNS) was predominantly isolated preoperatively from the conjunctiva, nose, and lacrimal sac and postoperatively from the conjunctiva. Preoperative and postoperative conjunctival culture positivity rates were similar between all the groups (p>0.05). A statistically significant difference in the growth rate of culture in the lacrimal sac was observed between the three groups (p=0.001). CNS and Staphylococcus aureus cultures were predominantly sensitive to linezolid, teicoplanin, tigecycline, vancomycin, and mupirocin. Conjunctival normalization times were similar between the three groups (p>0.05). Anatomical and functional success rates were not found to be significantly correlated with preoperative conjunctival and lacrimal sac culture positivity (p>0.05). Conclusions: Similar rates of preoperative and 1-week postoperative conjunctival culture positivity were observed in all the groups; a significantly lower bacterial growth rate was observed in postoperative conjunctival cultures. CNS was the most commonly isolated organism. Bacterial growth rates in the lacrimal sac samples were significantly higher in the EN-DCR group. Bacterial growth rates obtained preoperatively from the conjunctival and lacrimal sac culture samples were not correlated with DCR success.

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Bacteriological profile in conjunctival, lacrimal sac, and nasal specimens and conjunctival normalization time following external, endoscopic, and transcanalicular multidiode laser dacryocystorhinostomy

M. Faruk Oktay

Papers

Prospective comparison of 3 dacryocystorhinostomy surgeries: external versus endoscopic versus transcanalicular multidiode laser.

Bacteriological profile in conjunctival, lacrimal sac, and nasal specimens and conjunctival normalization time following external, endoscopic, and transcanalicular multidiode laser dacryocystorhinostomy