A congenital dacryocystocele is a rare disorder that leads to obstruction of the nasolacrimal duct and can cause congenital lacrimal duct obstruction. The nasolacrimal duct is derived from the ectoderm and is located between the maxillary process in the middle of the face and the lateral nasofrontal process. It is formed in the first 3 months of gestation and extends to the head and tail to form a tubular structure at 6 months of gestation . Approximately 30% of newborns develop partial obstruction of the nasolacrimal duct ; however, 85% to 95% of lacrimal duct obstructions will reopen spontaneously after approximately 1 year without treatment . When a congenital dacryocystocele forms, spontaneous regression of >50% of the congenital dacryocystocele occurs within 3 months, >80% occurs within 6 months, and 95% occurs within 1 year . Approximately 76% of children can reportedly be cured with nonsurgical treatment, including lacrimal sac massage, lacrimal duct irrigation, and other conservative treatments [8,9]. However, the disease is easily complicated by dacryocystitis or periorbital cellulitis; thus, early intervention is required. In this study, a total of 28/40 (70%) patients had dacryocystitis, including 15/20 (75%) patients in group A and 13/20 (65%) patients in group B. However, in this study, 21.6% (8/37) of unilateral patients and 100% (3/3) of bilateral patients exhibited intermittent open-mouth breathing, including 3 bilateral and 4 unilateral patients who manifested respiratory sounds while breathing, especially when breast-feeding. We utilized an endoscopic technique in our pediatric otolaryngology department that was combined with CT, lacrimal lipiodol angiography, and nasal endoscopy, and the diagnosis rate of congenital dacryocystocele in our outpatient clinic reached 100%. Several previous studies, such as the work of Roy  and Paysse , have also emphasized the role of nasal endoscopy combined with CT scanning. The combination of CT and lacrimal lipiodol angiography (Fig. 4) takes the safety of the examination into consideration and can accurately display the three main pathological and imaging features of the disease , including various degrees of unilateral or bilateral nasolacrimal duct expansion, a cyst in the inner canthus, and an inner cyst in the inferior nasal meatus . If the clinical findings cannot be confirmed, CT can be used to achieve a diagnosis of lacrimal cysts by excluding brain encephalocele, sweat gland cysts, dermoid cysts, and other lacrimal system abnormalities [14-16]. If CT suggests meningeal encephalocele, further confirmation by magnetic resonance imaging is required. Pink cystic masses can be directly observed by nasal endoscopy. The lower turbinate is usually pushed horizontally; if secondary infection occurs, the condition can rapidly develop into acute dacryocystitis and periorbital cellulitis . Previous reports have described confirmation of the diagnosis by ultrasound  or magnetic resonance imaging . Prenatal ultrasound can detect this disease early .
Marsupialization under nasal endoscopy and placement of the syringing device under nasal endoscopic vision eliminate the risk of false lacrimal passage formation, which usually occurs during blind probing, and reduce the incidence of postoperative infection.
In 2014, Ali et al.  described the classic marsupialization technique. This surgery seems to be more suitable for cysts in larger sinuses because a sickle knife is used to make horizontal and vertical incisions in the middle of the cyst to perform a cruciate incision of the full thickness of the cyst wall. Through contraction of the four separate petals during the healing process, a larger opening is formed, and each flap of the mucous membrane is prevented from overlapping to promote healing. However, our experience is that when the entire layer of a large inflammatory cystic mass is cut, due to the pressure of the cyst, the contents of the cyst will overflow quickly, and the cyst wall will collapse immediately. It then becomes difficult to make a vertical incision. Therefore, we adopted the following method. First, we cut the full thickness of the cyst wall with a sickle knife, and the cyst collapses after the contents overflow. Then, we use a microdebrider with a diameter of 2 mm to remove most of the redundant cyst wall and smoothly trim the edge. The advantage of this type of operation is that cyst fenestration is exact and complete, drainage is unobstructed because there is no overlapping mucous membrane flap, and adhesion will not cause recurrence. The disadvantages include that specific equipment is required, the operation time is prolonged, and most of the mucous membrane of the cyst needs to be removed. Compared to the classical marsupialization technique described by Ali et al., the surgical procedure adopted in this study can be considered extended marsupialization.
Due to complete removal of the cyst from the inferior nasal passage, a wide nasolacrimal duct opening is formed on the affected side; this greatly reduces the probability of surgical failure caused by postoperative synechiae. The opening of the lacrimal duct reduces the pressure in the lacrimal duct system, the occluded valve of Rosenmuller opens naturally, the lacrimal sac decompresses, the cyst in the inner canthus regresses spontaneously, and key physiological functions are preserved. Therefore, this procedure can be considered a functional operation of great clinical significance. Postoperative mucosal hemorrhage can be treated under nasal endoscopy. The cyst itself does not usually have a rich blood supply, and precise cutting with an electric cut-off drill does not damage adjacent structures; thus, little intraoperative bleeding occurs. Avoidance of nasal filling after surgery is beneficial to the postoperative care of newborns and young infants and meets the postoperative care requirements for nasal surgery in children. In the present study, no postoperative complications of nasal bleeding occurred in Group A. In contrast, when lacrimal probing is performed blindly, nasal bleeding depends on the operator’s personal experience and skills. The technique causes great damage to the lacrimal system mucosa, causes a new scar to form after surgery, and results in local stenosis, which will lead to secondary lacrimal stenosis. These problems are why multiple probing procedures are performed to cure congenital dacryocystoceles. During the follow-up in Group B, we found that the probing failure that had occurred in one patient was caused by a decrease in the diameter of the probe opening during the second probing, even resulting in atresia after surgery. The possible reason for this failure is that due to the high pressure in the lacrimal system preoperatively, the membranous nasolacrimal duct can prolapse to form a large cyst in the inferior nasal passage. After penetration, the pressure in the lacrimal duct is reduced, but the small penetrated opening does not allow for adequate drainage. If the cysts are not removed, stimulation by inflammatory secretions and the inflammatory response of the postoperative mucosa eventually lead to re-atresia of the opening. Although no definite conclusion has been reached regarding the size of the cyst opening compared to the narrow opening after penetration, the spacious drainage opening after marsupialization under nasal endoscopy has obvious advantages with respect to preventing postoperative re-occlusion. Collaboration between rhinologists and ophthalmologists is indispensable when performing marsupialization under nasal endoscopy to ensure efficacy and reduce complications.