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MINISTRY OF EDUCATION AND TRAINING MINISTRY OF HEALTH HANOI MEDICAL UNIVERSITY HÀ HUY THIÊN THANH RESEARCH ON THE APPLICATION OF ENDOSCOPIC SURGERY IN THE TREATMENT OF NASOLACRIMAL DUCT OBSTRUCTION Sp[.]
MINISTRY OF EDUCATION AND TRAINING MINISTRY OF HEALTH HANOI MEDICAL UNIVERSITY HÀ HUY THIÊN THANH RESEARCH ON THE APPLICATION OF ENDOSCOPIC SURGERY IN THE TREATMENT OF NASOLACRIMAL DUCT OBSTRUCTION Specialism: Ophthalmology Code: 9.72.01.57 ABSTRACT OF THESIS HÀ NỘI - 2022 The thesis has been completed at HÀ NỘI MEDICAL UNIVERSITY Superviors: Supervisor 1: Assoc Prof PhD Phạm Thị Khánh Vân Supervisor 2: PhD Nguyễn Quốc Anh Reviewer 1: Reviewer 2: Reviewer 3: The thesis will be presented in front of board of university examiner and reviewer lever at…………………… on ……………………2022 This thesis can be found at: National Library: National Medical Informatics Library Library of Hanoi Medical University LIST OF PUBLISHED WORKS RELATED TO THE THESIS Hà Huy Thiên Thanh, Nguyễn Quốc Anh, Phạm Thị Khánh Vân Post-operative evaluation using dacryocystorhinostomy ostium scoring and factors associated with success after endoscopic dacryocystorhinostomy Vietnam medical journal, No 02, August 2020, p 82 - 85 Hà Huy Thiên Thanh, Nguyễn Quốc Anh, Phạm Thị Khánh Vân Primary endoscopic dacryocystorhinostomy: - month outcomes and associated factors Journal of medical research, Vol 136, No 12, Dec 2020, p 110 - 118 INTRODUCTION Necessity of the thesis Naso-lacrimal duct obstruction (NLDO) is the cause in 30% of tearing and is common in middle-aged and elder adults The disease greatly affects vision, quality of life and increases the risk of infection in other surgical interventions Untreated disease can lead to acute dacryocystitis, dacryocele, lacrimal sac abscess, orbital cellulitis or even cavernous sinus thrombosis Therefore, addressing NLDO is an urgent requirement In 1904, Toti introduced the external dacryocystorhinostomy (DCR), which became popular in the 20 th century with good outcomes but not without some limitations such as compromised lacrimal pump, risk of bleeding, long recovery time and face scars Towards the end of the 20 th century, the invention of the endoscopic system facilitated the development of minimally invasive surgery and endoscopic transnasal DCR was introduced in 1989 by McDonogh and Meiring This technique was widely accepted by many surgeons because the direct access route through the nose helps to shorten surgery and recovery duration, avoid skin scarring and limit the impact on the lacrimal pump Endoscopic is increasingly being improved with supportive measurements such as bone drilling and anti-metabolic drugs Therefore, this method has become the first choice in the treatment of NLDO In Vietnam, this surgery has been reported by several authors such as Nguyen Huu Chuc (2008), Ngo Thi Anh Tai (2005) and is increasingly accepted as the first-line treatment, similar to the global trend Since 2015, endoscopic DCR has been performed at Vietnam National Eye Hospital with more than 500 cases However, there have been no studies to comprehensively evaluate surgical outcomes and related factors Objectives of the thesis - Evaluate the surgical outcomes of endoscopic surgery in the treatment of NLDO at Vietnam National Eye Hospital - Analyze the factors related to surgical outcomes Scientific and practical significance of the thesis - The study reported anatomical and functional outcomes and the follow-up of post-operative ostium for a sufficient duration until the outcomes were stable, which demonstrates that this is an effective and safe surgery - This is the first study in Vietnam to report the application of the dacryocystorhinostomy ostium scoring (DOS) in the clinical follow-up after endoscopic dacryocystorhinostomy, contributing to the development of an effective and less invasive monitoring protocol, reducing the need for lacrimal irrigation risking canalicular injury - The thesis suggested a number of factors associating with the anatomical and functional outcomes, contributing to the indications, prognosis and expectations adjustment for surgeons and patients Structure of the thesis: The thesis is presented in 135 pages (excluding references and appendices), including introduction (2 pages), overview (32 pages), patients and methods (24 pages), results (31 pages), discussions (41 pages), conclusions (2 pages), recommendations (1 page), new conclusions (1 page) and further research directions (1 page) with 180 references Chapter 1: OVERVIEW 1.1 Anatomy and applied landmarks of the lacrimal system 1.1.1 Anatomy of the lacrimal system Tears from the ocular surface drain into the nose via the lacrimal system The naso-lacrimal duct is a continuation of the lacrimal sac, descending downward, outward, and posteriorly in the bony duct, ending in the inferior meatus The lower part of the duct is narrower in females than in males, which may be the cause of the female predominance in NLDO 1.1.2 Applied anatomical landmarks 1.1.2.1 Anatomy of the lacrimal groove The lacrimal groove is bordered by the anterior crest located on the maxillary bone and the posterior crest on the lacrimal bone Research on Vietnamese people showed that the average size of the lacrimal groove is 11,4x4,7 mm in males and 10,3x4,3 mm in females The lacrimal groove is shallower and thicker upward, where the maxillary bone predominates and terminates at the fronto-maxillary and fronto-lacrimal joints 1.1.2.2 Anatomical landmarks The lateral nasal wall consists of ridges, turbinates and meatus The main anatomical landmarks in endoscopic DCR are the axilla of the middle turbinate, the maxillary line, the uncinate and the agger nasi air cells Relation of the middle turbinate and the lacrimal groove Axilla of the middle turbinate is the most anterior point where the turbinate attaches to the frontal process of the maxillary bone It is suggested that the lacrimal sac is located at or behind the axilla and an anterior resection of the turbinate is required to expose the entire sac A study on computed tomography of Vietnamese showed that the average distance from the axilla to the bottom of the lacrimal sac was 7,8 mm Therefore, the upper border of the nasal mucosal flap is identified at 10 mm above the axilla and total bone removal in this area is important for improving long-term success Relation of the maxillary line and the lacrimal groove The maxillary line is a ridge running from the axilla of the middle turbinate to the base of the lower turbinate In 2009, Orhan et al reported that the maxillary line corresponds to the lacrimal sac in 90%, of which 69% overlaps with the maxillary-lacrimal joint Therefore, the maxillary line is used as a landmark to locate the incision of the nasal mucosa and the surgeon dissects behind this landmark at the first step of surgery Relation of the uncinate process and the lacrimal groove The upper vertical part of the uncinate is is directly related to the lacrimal passage The uncinate process is usually kept intact in routine DCR and is the posterior limit of the mucosal flap However, in Asian patients, some surgeons favor resection of the uncinate to expose the lacrimal sac In a study on Vietnamese people, Nguyen Huu Chuc (2008) reported 93% of cases where the uncinate was adjacent to the lacrimal groove and based on the attachment of the uncinate, the position of the tear groove could be identified accurately Relation of the agger nasi air cells to the lacrimal groove The agger nasi cells is represented by a raised mound in front of the middle turbinate and occurs in 80-98,5% of the population This structure is closely related to the posterior margin of the lacrimal groove and lies directly next to it Therefore, in order to expose the posterior medial aspect of the lacrimal sac, it is necessary to remove part of the agger nasi cells 1.2 Clinical and paraclinical presentations of NLDO 1.2.1 Chronic dacryocystitis Catarrhal dacryocystitis is characterized by persistent epiphora and angular conjunctivitis The patient may have clear tearing or sticky mucus discharge In this case, there is little clinically obvious dilatation of the lacrimal sac or even atrophy of the lacrimal sac due to fibrosis During irrigation, there is clear regurgitation from opposite punctum Chronic suppurative dacryocystitis is characterized by epiphora and discharge accompanied by dilated lacrimal sac containing purulent mucus Patients are concerned about the secretions causing sticky eyelashes and irritation to the lower eyelid skin and the inner angle Reflux of purulent discharge from both puncta is clearly presented on palpation of the sac During irrigation, there is often purulent and/or mucus discharge regurgitation from the opposite punctum Lacrimal mucocel is a cystic swelling due to accumulation of secretions which cause dilation of the lacrimal sac and collapse of Rosenmüller valve Absence of discharge reflux from sac into conjunctival fornix causes less conjunctival irritation and epiphora However, the mucocele causes distortion of the medial angle and can lead to an abscess of the lacrimal sac causing an emergency situation During irrigation, the lacrimal sac is often inflated and there is no passage into the nasopharynx Computed tomography of the lacrimal sac in lacrimal mucocele and chronique dacryocystitis can show a dilated, pus-filled lacrimal sac 1.2.2 Acute dacryocystitis Acute dacryocystitis is caused by secondary infection of the lacrimal sac and surrounding tissues The clinical presentations of acute dacryocystitis are diverse, ranging from painful swelling and redness to abscess of the lacrimal sac More severe presentations include orbital cellulitis (3%) and fever (6%) A sac abscess occurs in 25% and percutaneous fistulas form in 6% due to rupture or surgical drainage 1.3 Application of endoscopic surgery in the treatment of NLDO 1.3.1 Brief history The introduction of the Hopkins rigid endoscope and improvements with smaller sizes and a variety of viewing angles helped with accurate surgical maneuvre Endoscopic DCR was first performed by McDonogh and Meiring in 1989 and since then has attracted the interest of lacrimal surgeons Up to now, endoscopic DCR has developed very strongly The most common techniques including mechanical instruments and electric drill were described by Wormald in 2002 Other additional techniques are mucosal flaps, anti-metabollic agents and silicone stents 1.3.2 Indications and contraindications Currently, the most common indication for endoscopic DCR is primary acquired NLDO that may be associated with chronic dacryocystitis Contraindications of endoscopic surgery include suspected lacrimal sac tumor and pre-saccal disease such as punctal and canalicular obstruction 1.3.3 Techniques In the mucosa-sparing technique, the first transverse incision is made 810 mm above the axilla of the middle turbinate and is extended 10 mm anteriorly A lower transverse incision is made parallel to the first one, starting from the attachment of the uncinate process to the frontal process and then a longitudinal incision connects the anterior ends of the two transverse ones After that, the nasal mucosa flap is reflected from the nasal wall and folded posteriorly to expose the maxillary bone The thick part of the frontal process is removed until the lacrimal sac is fully exposed The surgeon makes a longitudinal incision in the anterior third of the wall and excise the anterior mucosal flap of the sac The lacrimal and nasal mucosal flaps are fashioned and positioned to achieve apposition In the final step, a silicone stent is placed via the canaliculi and tied in the nasal cavity 1.3.4 Surgical outcomes 1.3.4.1 Results from international and domestic researches Regarding the overall outcomes, Vinciguerra et al (2020), in a systematic review of endoscopic DCR techniques, reported a success rate of 90% for mechanical and 91% for powered surgery Long-term patient follow-up up to 10 years after surgery showed a 97,7% success rate In 2020, a systematic review also showed that endoscopic and external DCR had success rates of 89,8% and 89,5%, respectively The rate of functional success after DCR is often reported to be lower than that of anatomical success, possibly up to 10-15% The cause may be due to abnormal function of lacrimal pump, orbicularis and ocular surface in elderly patients who often require primary NLDO treatment In the treatment of acute dacryocystitis, endoscopic DCR can be performed safely in the acute phase, involving drainage of an abscess The success rate of both endoscopic and non-endoscopic endonasal surgery is over 90% and is maintained in long-term follow-up In Vietnam, the first on endoscopic DCR performed by Pham Thi Khanh Van et al (2004) reported a success rate of 80% after months To create a premise for endonasal endoscopic techniques, Nguyen Huu Chuc (2008) studied anatomical landmarks in surgery Ngo Thi Anh Tai (2005) studied on chronic dacryocystitis at Hue University of Medicine and Pharmacy and reported a success rate of 82,6% Studies in Vietnam are diverse on surgical aspects, however, more studies are needed to monitor long-term outcomes and learn about factors related to surgical outcomes 1.3.4.2 Methods of evaluating outcomes Functional outcomes To evaluate symptoms, Munk et al (1990) used a 5-level selfdetermined rating scale for epiphora Anatomy outcomes Evaluation of the change in tear menicus height: by integrated ruler on slit lamp Evaluation of lacrimal drainage: by lacrimal irrigation Postoperative ostium assessment: The Dacryocystorhinostomy ostium scoring (DOS) was recommended by Ali et al (2014) for postoperative follow-up based on existing evidences and their experiences, using the most important features of ostial morphology and function 1.3.4.3 Complications of surgery Endoscopic DCR is safe with low complication rate In the study of Leong et al (2010), the complication rate was 14,4% in the endoscopic group Reports frome experienced centers also showed that complication rate is less than 5% and serious complication rate is less than 2% When performed in the setting of inflammation and infection, such as acute or suppurative dacryocystitis, the complication rate was not higher (5,6%) Complications during surgery: Bleeding, damage to the medial wall of the orbit, damage to the punctum and canalicula Complications after surgery: Infection, bleeding after surgery, canalicular obstruction, complications of the silicone stent 1.3.4.4 Pros and cons of surgery Advantages: less intraoperative bleeding, no scarring, preservation of lacrimal pumping mechanism, reduced hospitalization, opportunity to treat nasal diseases at the same time, faster recovery and surgery duration Cons: high cost of endoscopic equipments, long-time training to master this technique, especially for ophthalmologists In addition, other diseases such as sac tumors are difficult to detect, the technique of suturing the mucosal flaps is difficult and meticulous hemostasis is required during surgery to clearly observe the surgical field 1.3.5 Factors related to surgical outcomes 1.3.5.2 Preoperative factors Age and gender: Research on the relationship of age and gender with surgical outcomes still has conflicting results History of inflammation or infection: A history of chronic inflammation has been reported to associate with surgical outcomes With a history of dacryocystitis, Woog’s study (2007) found a trend toward higher success than patients without such a history Regarding the lacrimal sac, Mannor and Millman (1992) reported a statistically significant higher success rate in patients with dilated or normal lacrimal sacs (82%) than in those with small atrophy ones (29%) Hammoudi et al (2001) also found that large lacrimal sacs help to widen the ostium and the success rate is 5,7 times higher than in the group of patients with small atrophic lacrimal sac 1.3.5.3 Factors during surgery An associated factor that has been widely mentioned is the ostium size However, two groups of authors studying the effect of rhinostomies on surgical outcomes reported that both the rhinostomy and the final ostium sizes have no predictive value for surgical outcomes 1.3.5.4 Postoperative factors The success rate of endoscopic DCR may decrease with prolonged follow-up: Cohen et al (2020) found a reduced success rate at 10-year follow-up (80%) compared with immediate postoperative results (93,8%) The parameters to evaluate the morphology and function of the ostium and the total score were also related to the surgical outcomes Location of the ostium: The location of the ostium is evaluated in relation to the axilla of the middle turbinate Most of the ostium is ideally located superiorly anterior to the turbinate Occasionally, the ostium may be posterior or below it, depending on the location of the lacrimal sac Shape of the ostium: If healing is good, ostium are round or oval A good ostium base is clear but shallow The ostium is crescentric or vertical slit if healing is abnormal and scarring is localized Size of the ostium: The ostium’s degree of shrinkage from the original size varies widely depending on the study However, this rate is only 20% if the mucosa is tightly apposed during surgery and the healing process is good Most ostia shrink in the first weeks and stay unchanged after that Ostium cicatrization: Abnormal healing of the stoma can result in partially or completely occluding scars Regular monitoring of the ostium helps the surgeon understand more about the postoperative scar response and identify areas to modify in the technique Occluding scars requires surgical intervention and anti-metabolic agents to remove the scar Ostial or periostial synechiae: Synechia is caused by mucosal damage and poor postoperative treatment The incidence of synechia is low (about 4%) Evaluation of synechiae in the ostial area at an early stage is important because if it directly affects tear drainage, early lysis may be necessary to prevent the synechiae from becoming permanent Internal common opening: The ideal location of the internal common opening of the canaliculi is at the base of the ostium Movement of the opening can be seen when blinking or when dye is present Obstructive structures such as fibroids or granulomas covering the opening should be detected and resected if necessary Silicon stents: After removal of secretions, the entire tube is observed for movement It is important to detect contact granuloma or entrapment of the tube in the soft tissue for early removal If the tube is cut short and the scarring is intense, it can be entrapped in the tissues, but this is rare Functional endoscopic dye test: Moore et al (2002) found this test to be valuable in evaluating the patency of the ostium and suggested this should be a required criterion for the functional success of the surgery 10 2.6 The Dacryocystorhinostomy Ostium Scoring (DOS) system Table 2.1 The Dacryocystorhinostomy Ostium Scoring (DOS) system Parameter Subparameter Score In front and above axilla of middle turbinate (MT) Behind axilla of MT Location of ostium Below axilla of MT Not recognizable Circular/Oval with shallow base Circular/Oval with deep base Shape of the ostium Crescentric/ vertical slit/ others Not recognizable > x mm – x – mm 3 Size of the ostium (length x width) – x – mm Obliterated None Pseudocicatrix Ostium cicatrization Incomplete cicatricial closure Complete cicatricial closure None Nonostial/ Noninterfering Synechiae Interfering ostial Complete synechial closure Uncovered by edge, dynamic Overhanging edge, dynamic Internal common Partially obstructed/membrane opening (ICO) Not traceable with Functional endoscopic dye test/ irrigation Course traced, move with blink/ unintubated Intubated but lost/ removed before Silicone stents weeks Associated contact granuloma Entrapped in ostial tissues Spontaneous and in < minute Functional Endoscopic Spontaneous and in > minute Dye Test (FEDT) Not spontaneous but positive with 11 Ostium granuloma 10 Other ostium pathologies irrigation Negative with irrigation None On one or more edges Peri-ICO/ threatening ICO Covering/ obstruction ICO None minor > minors Major 4 Chapter RESULTS 3.1 Characteristics of patients 3.1 Patient characteristics Age and gender In the 67 patients of the study, mean age at the time of surgery was 52,6 ± 11,0 Females accounted for the majority with the rate of 94,0% Preoperative clinical features The number of cases being operated on the right and left side is equal with 42 cases each side, 25,4% of cases being operated on both sides 64,7% of cases have a combination of epiphora and purulent discharges The most common symptom is epiphora with the rate of 97,6% The median duration of epiphora was 24 months Before surgery, 95,2% of epiphora was grade or higher, in which 48,8% was at level and 67,9% of cases had purulent discharges The median duration of discharges was 12 months The mean preoperative tear meniscus height was 1,1 ± 0,4 mm Among the clinical forms of NLDO, chronic dacryocystitis is the most common, accounting for 60,7% The total rate of dacryocystitis was 71,4% 64,9% of cases had dilated lacrimal sac on preoperative imaging Surgical features The average surgical duration was 46,5 ± 9,1 minutes Most (97,6%) of cases had a surgery duration of 60 minutes or less Average dimensions of rhinostomy: horizontal diameter 6,4 ± 0,1 mm, vertical diameter 14,8 ± 0,2 mm, estimated surface area 95,3 ± 2,6 mm2 Only 13,1% of cases was of grade bleeding and were recorded as complications in surgery All of these cases were managed with intraoperative electrocautery hemostasis 3.2 Surgical outcomes 12 3.2.1 Anatomical outcomes 3.2.1.1 Tear menicus height The height of the tear menicus decreased from 1,1 ± 0,4 mm on admission to 0,5 ± 0,4 mm after surgery, then stabilized through follow-ups at month and months At months, the mean menicus height was 0,6 ± 0,4 mm and decreased to 0,4 ± 0,4 mm at the final follow-up The difference was statistically significant between pre-operative and each of post-operative measurements and between months and 12 months 3.2.1.2 Features of the post-operative ostium Table 3.1 Features of ostium at follow-ups Times months 12 months p* Features n % n % In front and above axilla 66 78,6 66 78,6 Behind axilla 0 0 Location 1,00 Below axilla 17 20,3 17 20,3 Not recognizable 1,2 1,2 Circular/ Oval with 45 53,6 37 44,1 shallow base Circular/ Oval with 18 21,4 26 31,0 1,00 Shape shallow base Crescentrict/ vertical slit 18 21,4 17 20,2 Not recognizable 3,6 4,7 > x mm 0 0 Size (length - x - mm 31 36,9 34 40,5 0,71 x breadth) < x mm 49 58,3 44 52,4 Not recognizable 4,8 7,1 None 43 51,2 53 63,1 Pseudo cicatrix 13 15,5 7,1 Incomplete cicatricial Cicatrization 24 28,6 20 23,8 0,005 closure Complete cicatricial 4,7 5,9 closure None 72 85,7 74 88,1 Noninterfering 10,7 8,3 Synechiae 0,31 Interfering ostial 3,6 3,6 Complete closure 0 0 Internal Uncovered by edge 53 63,1 46 54,8 0,03 common Overhanging edge 19 22,6 22 26,2 13 opening (ICO) Partially obstructed 9,5 11 13,1 Not traceable 4,8 5,9 Move with blink 74 88,1 74 88,1 Lost/ removed before 4 4,8 4,8 Silicone weeks 1,0 stents Associated granuloma 2,3 2,3 Entrapped 4,8 4,8 Spontaneous in 1 10 11,9 10,7 endoscopic 0,36 Only with irrigation 15 17,8 12 14,3 dye test Negative 4,8 5,9 None 72 85,7 82 97,6 On edges 8,3 0 Granuloma 0,004 Threatening ICO 4,8 1,2 Obstructing ICO 1,2 1,2 None 81 96,4 80 95,2 minor 3,6 4,8 Other 0,32 pathologies > minor 0 0 Major 0 0 In our study, none of the ostia were poorly classified at both points of assessment The rate of good ostia at months was 51,2% (43/84) and increased to 57,1% (48/84) at year 3.2.1.3 Lacrimal patency Graph 3.1 Lacrimal patency at follow-ups 14 week after surgery, 98,8% had a patent passage This rate decreased after month, months and months with a statistically significant difference and stable at 86,9% The mean time of recurrence was 14,1 ± 9,3 weeks (1 - 24 weeks) Causes of recurrence Table 3.2 Causes of recurrence Causes Number (n) Percentage (%) Cicatrization 11 100 Synechiae 18,1 Granuloma 9,1 Canalicular obstruction 27,3 Sump syndrome 9,1 Of the 11 relapsed cases, were re-operated to widen the ostium After one year of follow-up, 7/8 cases had patent drainage and reduced symptoms after the revision surgery Classification of anatomical outcomes Anatomical outcomes were good, accounting for 86,9% at the first follow-up visit This rate gradually decreased to 67,9% after months and increased slightly to 69,0% after 12 months The rate of good outcomes at 1-week and 1-month follow-up was higher than at the next follow-up visits with a statistically significant difference However, there was no difference in the rate of good outcomes between and 12 months 3.2.2 Functional outcomes 3.2.2.1 Decrease of epiphora Graph 3.2 Decrease of epiphora at follow-ups 15 At the first follow-up, the epiphora was relieved in 90,5% This rate decreased statistically through out time and reached 83,3% after year The mean time to recurrence was 11,1 ± 9,1 weeks 3.2.2.2 Classification of functional outcomes Regarding immediate functional outcomes after surgery, there were 77,4% good outcomes, this decreased to 59,5% after months and increased to 70,2% at the last follow-up 3.2.2.3 Relationship between functional and anatomical outcomes In 86,9% with patent drainage, 4,8% still had significant tears 3.2.3 Complications of surgery Intraoperative complications were presented in 14,3% Three types of complications were recorded: severe haemorrhage in 13,1%, punctal tear in cases and orbital fat prolapse in case The overall rate of postoperative complications was 19,1% The most common complication was canalicular obstruction in 8,3% Soft tissue infection and punctal tear accounted for 3,6% each 2/84 cases had early loss of the silicone tube case had adhesion of the upper and lower puncta, which were managed by lysis and removal of the stent 3.3 Factors related to surgical outcomes 3.3.1 Factors related to anatomical outcomes 3.3.1.1 Preoperative factors The left cases had more good and moderate outcomes than the right ones, the difference was statistically significant with p = 0,02 Sex, clinical forms, dilatation of lacrimal sac, number of eyes affected were not statistically associated with postoperative lacrimal patency Regarding preoperative symptoms, cases with menicus height of mm or less had 4,63 times chance of better anatomical outcomes than those with menicus height >1mm at admission, the difference is statistically significant The degree of epiphora according to Munk grade was not significantly associated with the anatomical outcomes 3.3.1.2 Intraoperative factors The operative duration and the dimensions of the rhinostomy were not significantly different between groups with good to moderate and poor anatomical results 3.3.1.3 Postoperative factors The cases with early relief of epiphora had 8,9 times chance of good to moderate anatomical outcomes than the other group, p < 0,01 Cases with complications in surgery had a 4,64 times risk of poor surgical outcomes than those without complications Cases with 16 complications after surgery have nearly times risk of poor surgical outcomes compared with those without complications Comparing the features of ostium at the time of silicone tube removal in the groups with good to moderate and poor anatomical outcomes, the study showed that the parameters of the shape, size, synechiae, cicatrization, common internal opening, silicone stent, functional dye test and total DOS scores were significantly associated with surgical outcomes Accordingly, the groups with round or oval shape, medium or larger size, pseudocicatrix or no cicatrization, no ostial interfering synechiae, flexible internal common opening, good motility of the silicone tube, positive dye test and good DOS were likely to have higher good to moderate anatomical outcomes than the other group 3.3.2 Factors related to functional outcomes 3.3.2.1 Preoperative factors There was no significant relationship between sex, clinical form, lacrimal sac dilatation, eye operated and number of affected eyes with functional outcomes at the final follow-up Regarding the preoperative symptoms, the cases with grade or more epiphora had a significant worse functional outcome than those with grade or lower Tear menicus height was not significantly associated with functional outcomes at the end of follow-up duration Mean age of the group with poor functional outcome was significantly higher than that of the group with good to moderate functional outcomes (58,75 years old versus 52,52 years old) There was no significant difference between the two groups in the duration of epiphora and discharge 3.3.2.2 Intraoperative factors There were no significant differences in operative duration and rhinostomy measurements between groups with different functional outcomes 3.3.2.3 Post-operative factors Early relief of epiphora or intraoperative and postoperative complications were not significantly associated with functional outcomes The cases without ostial cicatrization had good to moderate functional outcomes significantly more frequent than the group with scarring The group with a positive dye test in < minute had a 10,8 times higher ability to reduce epiphora than the group with slow positive or negative test The cases with good to fair DOS were 22 times more likely to improve symptoms than the group with a moderate or less total score 17 Chapter 4: DISCUSSION 4.1 Characteristics of patients Age and genders The mean age (52,6 ± 11,0) was consistent with classic literature's comments that primary NLDO is more frequent in middle-aged and older age groups, with the mean ages in studies from 31,8 to 66 The proportion of females in this study was high (94,0%), possibly because the diameter of the lacrimal duct was smaller than that of males and the angle formed between the bony lacrimal duct and the nasal floor was more acute Preoperative clinical features Many studies have noted that tearing occurs in 100% of cases Our rate of purulent discharges (67,9%) was higher than that of Ali et al (2015 14%) but lower than the studies which selected only chronic dacryocystitis We chose to analyze tear menicus height because of its objectivity, quantification, ease of use with readily available tools and noninvasiveness, with a preoperative mean of 1,1 ± ,4 mm This is also a sign used by many researchers on lacrimal surgery to diagnose disease and evaluate surgical results In our study, 71,4% had dacryocystitis, the chronic form of which is a classic indication of endoscopic DCR For acute dacryocystitis, we managed according to the protocol proposed by Chong et al (2020), using high-dose systemic antibiotics immediately from admission and the surgical procedure was performed as in other cases The outcomes were similar to those in the study of the above authors, with the effectiveness of reducing swelling and pain very soon after surgery up to days after surgery and completely eliminating symptoms within week Surgical features The surgical duration in this study was 46,5 minutes, equivalent to the reports of other vietnames authors but quite high compared to international authors such as Trimachi et al in 2020 (25 minutes), Roh et al 2016 (29 minutes), may be because surgical duration depends on the surgeon's technique and familiarity with endoscopic DCR Research on the trends of endoscopic DCR in the Asia-Pacific region in 2018 also reported that most surgeons need 31-60 minutes The average size of the vietnames lacrimal groove is 4,7x11,4 mm Therefore, in surgery, the minimum size of rhinostomy was 10 x mm and the upper border of the rhinostomy was always above the common canalicular opening However, the rhinostomy was keep at just sufficient size to limit damage to the surrounding tissues ... stents weeks Associated contact granuloma Entrapped in ostial tissues Spontaneous and in < minute Functional Endoscopic Spontaneous and in > minute Dye Test (FEDT) Not spontaneous but positive with... A lower transverse incision is made parallel to the first one, starting from the attachment of the uncinate process to the frontal process and then a longitudinal incision connects the anterior... The clinical presentations of acute dacryocystitis are diverse, ranging from painful swelling and redness to abscess of the lacrimal sac More severe presentations include orbital cellulitis (3%)