acquired nasolacrimal duct obstruction ( nldo ) is a common disorder that occurs more frequently in females [ 1 , 2 ] . external dcr was first described by toti in 1904 , and the procedure has been modified many times by different surgeons over the years . the endonasal technique was first described by west in 1910 . however , since the early 1990s minimally invasive microendoscopic transcanalicular therapeutic techniques such as laser dacryoplasty ( ldp ) or microdrill dacryoplasty ( mdp ) have become more and more popular [ 5 , 6 ] . these procedures allow the physiology of the lacrimal drainage system to be preserved intact and obviate the need for an external dcr . thus , in specialized centers the number of external dcrs performed has decreased markedly , and external dcr is usually chosen only when transcanalicular microendoscopic techniques are contraindicated , such as in revision operations or in complicated or traumatic cases [ 58 ] . the purpose of the current study was to evaluate preoperative characteristics and postoperative outcomes of external dcr in this new and demanding indication area at a tertiary referral center specializing in lacrimal duct surgery in germany . in this study we retrospectively reviewed the medical records of all patients who had undergone lacrimal surgery at a tertiary eye care center between 2009 and 2011 . the retrospective study was approved by the local ethics committee and adhered to the tenets of the declaration of helsinki . inclusion criteria are as follows : adult patients ( age over 18 years);patients with acquired nldo;patients s / p external dcr performed at our department between 2009 and 2011.the extracted data included patient demographics , side of obstruction , duration of symptoms , previous dacryocystitis , previous lacrimal duct surgery , postoperative complications , and surgical outcome . adult patients ( age over 18 years ) ; patients with acquired nldo ; patients s / p external dcr performed at our department between 2009 and 2011 . in our department external dcr is generally performed under general anesthesia . an incision was made medial to the angular vein at the level of the medial canthal ligament . an osteotomy with a mean diameter of 10  mm was created and the lacrimal sac opened . posterior and anterior mucosal flaps were made and all patients were intubated with silicone tubes . the skin was closed with a 6 - 0 polypropylene suture . postoperative , long - term results regarding patient satisfaction and success rate were evaluated by telephone survey in october 2015 . success was defined as full resolution of symptoms and no postoperative dacryocystitis without additional postoperative lacrimal duct surgery . regarding the analysis of long - term outcome , patients were also asked to rate their satisfaction on a scale of 1 to 10 ( 1 = extremely dissatisfied to 10 = extremely satisfied ) . ibm spss statistics 22 for windows ( ibm corporation , somers , ny , usa ) was used for statistical analyses . fisher 's exact test was used to compare the results of dcr surgeries in the different subgroups . from the medical records of a total of 1010 patients who had undergone lacrimal duct surgery ( n = 1361 ) from january 2009 to december 2011 , 154 eyes of 146 patients ( 14.5% ) were included according to the previously mentioned inclusion criteria . mean preoperative age was 64.1  29.7 years ; 97 patients ( 66.4% ) were females and 49 patients ( 33.6% ) males . 138 had unilateral dcr ( right side , 75 ( 51.4% ) ; left side , 63 ( 43.2% ) ) , and 8 patients had bilateral dcr . the majority of the patients showed a duration of symptoms prior to first presentation at our department of more than one year ( figure 2 ) . 78.8% ( n = 115 ) patients complained of epiphora , and 55.5% ( n = 81 ) of patients had previously had acute or chronic dacryocystitis . 97 of the 146 patients ( 66.4% ) underwent dcr as the initial lacrimal duct surgery . 33.6% of patients ( n = 49 ) had had previous lacrimal duct surgery at another institution . the follow - up period ranged from 42 months to 80 months ( mean 61.7  5.1 months ) . the success rate of external dcr for patients with previous episodes of dacryocystitis was 82.7% , compared to 83.4% for patients without previous episodes of dacryocystitis . the success rate in patients without previous lacrimal duct surgery was 88.5% compared to 74.3% for patients with previous lacrimal duct surgery . the relative number of external dcr procedures in relation to the total number of all forms of lacrimal duct surgery performed at our department ( 14.5% ) agrees with results from other centers specializing in lacrimal duct surgery [ 5 , 7 ] . due to the development of microendoscopic transcanalicular techniques ( mdp and ldp ) over the last 10 years , the relative number of external dcr procedures performed has decreased markedly [ 57 ] . the minimally invasive , scarless endoscopic techniques have an acceptable success rate of up to 80% and are highly suitable for use as an initial treatment ( first - step procedure ) [ 57 ] . in recent years external dcr at our department has been performed mainly following dacryocystitis , as a secondary procedure after prior lacrimal duct surgery , or where transcanalicular microendoscopic techniques were contraindicated [ 58 ] . 66.4% of the patients were females , which is comparable with reports in the literature [ 1 , 2 , 9 ] . as dcr has a better success rate than transcanalicular microendoscopic techniques [ 1 , 6 , 7 , 912 ] , we applied dcr more frequently in elderly multimorbid patients to minimize the risk of revision surgery and further general anesthesia . about 50% of patients showed duration of symptoms of less than one year prior to first presentation at the clinic . some patients with chronic symptoms and a history of different forms of lacrimal duct surgery reported their symptoms to have lasted for several years . the success rate of external dcr in the literature has been reported to lie between 80% and 99% [ 1317 ] . comparing success rates of lacrimal duct surgery is a difficult task because different studies use different success criteria ( anatomic patency , improvement in tearing , or full resolution of symptoms ) and the follow - up time varies widely . evidence of anatomic patency to irrigation does not provide any information about the physiologic function of the dcr or patient satisfaction and can overestimate surgical success [ 1820 ] . in this study only patients who became completely asymptomatic following dcr , with a minimum follow - up time of 3.5 years after surgery , were rated as successes . this study investigated success rates of external dcr in some completely new and demanding indication areas : elderly patients ( 55.5% were older than 65 years ) , patients after dacryocystitis ( 55.5% ) , or patients after previous lacrimal duct surgery ( 33.6% ) . in this study 55.5% of the patients had had a previous episode of dacryocystitis ; there was no significant difference in the success rate of external dcr in patients with or without a previous episode of dacryocystitis . however , the relatively large sample size with a long follow - up ( mean follow - up of 61.7  5.1 months ) and the unusual study population ( reflecting real - life data from a tertiary referral center specializing in lacrimal duct surgery ) do add value to this study . in conclusion , with the rapid development and progress achieved in minimally invasive microendoscopic lacrimal duct surgery , the relative number of external dcrs performed as first - line treatment has decreased markedly and the indication area has changed completely over the last 10 years . however , external dcr is still the surgical treatment of choice with very good postoperative success rate in special indication fields .
purpose . this study aimed to evaluate long - term results of external dacryocystorhinostomy ( dcr ) at a tertiary eye care center specializing in lacrimal duct surgery in germany 
 . methods . 
 the medical records of 1010 patients with acquired nasolacrimal duct obstruction ( nldo ) , who had undergone lacrimal duct surgery at a tertiary eye care center , were reviewed . 
 only adult patients who had undergone external dcr were included . 
 the evaluation included the following parameters : age , gender , duration of symptoms , patient satisfaction , previous dacryocystitis , complication rates , and surgical outcome . results . 
 154 eyes of 146 patients ( 14.5% ) could be included in the study . 
 the average age was 64.1  29.7 years . 
 66.4% of patients were females and 33.6% were males . acute or chronic dacryocystitis was found in 81 patients ( 55.5% ) . 
 overall , 82.8% of patients had full resolution of symptoms . 
 the success rate of external dcr for patients with previous episodes of dacryocystitis was 82.7% compared to 83.4% for patients without dacryocystitis in their medical history . conclusion . in cases 
 in which transcanalicular microendoscopic techniques are contraindicated ( e.g. , after dacryocystitis ) or in complex cases where microendoscopic procedures have failed ( revision surgery ) , external dcr is still the surgical treatment of choice with very good postoperative success .