Patients
Forty children (50 eyes) with CNCD who underwent EN-DCR in the Department of Ophthalmology, Beijing Children's Hospital, Capital Medical University, from February 2012 to March 2016 were recruited into this study.
The diagnosis of CNCD was based on the history provided by the parents, the presence of symptoms of postpartum tear discharge with eye discharge, tests of the patency of the nasolacrimal canal conducted by irrigating the lacrimal sac, and a plain CT scan examination of the lacrimal duct. All cases completed a lacrimal CT scan within one month before surgery. Based on the report by Yu et al. [1] and Zhang et al.[2], lacrimal bony dysplasia was divided into bone nasolacrimal duct stenosis and bone atresia using CT scans (Figure 1).
The demographic and clinical information obtained in the patients is summarized in Table 1. The inclusion criteria were CNLDO with lacrimal bony dysplasia and an age of 2-18 years. Exclusion criteria included anomalies of the initial segment of the lacrimal passage, such as an absent inferior lacrimal puncta, absence or atresia of the inferior canal, traumatic lacrimal duct obstruction, lacrimal fractures induced by trauma, or lacrimal sac damage or displacement[12].
The indications for EN-DCR included cases that had been clearly diagnosed as CNCD. This type of case was also suitable for external dacryocystorhinostomy (DCR). In all cases, the parents in this group chose EN-DCR.
Ethics statement
This study was a retrospective study conducted in accordance with the principles of the Helsinki Declaration and approved by the Institutional Review Committee of Beijing Children's Hospital. Written informed consent was obtained from the parents of all patients before surgical treatment.
Surgical procedures
All procedures were performed under general anesthesia. Patients were required to remain supine with the head tilted back 15°. The nasal cavity on the surgery side was shrunk by using 1:10000 adrenaline . An endoscopic surgical system (Karl Storz SE and Co. KG, Tuttlingen, German) and 4.0-mm, 0° rigid nasal endoscopy (XiON GmbH, Berlin, German) were utilized. Other surgical equipment included an ENT power system (Medtronic PLC, Dublin, Ireland), a 4.0-mm ear burr, ophthalmic devices (including 3.0- and 2.0-mm rongeurs), and a Blasky child’s mucosal biting clamp.
The EN-DCR procedure was divided into three steps according to the guidelines for rigid endoscopy[13] (Figure 2). In step one, a 2.0 × 1.5 cm mucoperiosteal flap was made in the lateral nasal wall using a sickle knife starting from the front of the uncinate process (located mainly above the middle turbinate axillary) and reaching the periosteum. In step two, a bone window was made. As shown in Figure 1a-c, the frontal process of the maxilla was engaged using a rongeur from the suturae lacrimal maxillaris; the front lacrimal bone was separated and clamped, and a bone window was then formed with a diameter of about l × 1.5 cm. If the upper frontal process of the maxilla bone was thick, it could be ground down with an electric drill. Then, the medial lacrimal sac wall (with a light pale blue color) was exposed. After the lacrimal sac had been exposed, a Bowman probe was placed through the canaliculus into the sac. A vertical incision was then made with a sickle knife, and the medial wall of the sac was removed or the mucosal flap of the lacrimal sac was placed posteriorly, as shown in Figure 1d-f. In step three, the lacrimal sac was filled with vampire gauze or a gelatin sponge, which was pressed against the lacrimal sac mucosal flap to reduce movement and promote epithelialization of the anastomosis and to attenuate early postoperative bleeding.
Postoperative treatment and follow up
Systemic antibiotics and hemostasis were administered for three days after surgery. Saline nasal sprays were recommended for use in the month after surgery. A nasal wash was performed beginning on the fourth day using a nose washing apparatus. The first postoperative follow-up was arranged for the seventh day after surgery, when patients were subjected to a lacrimal passage flush. A solution containing tobramycin and dexamethasone (diluted 1:10) was used to flush the lacrimal passage from the upper and the lower punctum. In general, the first flush met with significant resistance and was accompanied by pus discharge and regurgitation. Sustained pressure washing was recommended until flushing became smooth, swallowing was confirmed, and regurgitation disappeared or until the discharge reflux fluid became clear. In the first month after surgery, a lacrimal passage flush was performed weekly; then, it was performed every two weeks for another two months. After one month, anastomotic exploration was routinely performed in all cases under local anesthesia according to the patient’s age, the degree of , and the timely discovery and cleaning of proliferated granulation tissue around the pore. At 8-18 months after the surgery, anastomotic exploration was again performed. Outpatient follow-up studies included a medical history, a fluorescein dye disappearance test (FDDT), lacrimal passage flush, and anastomotic exploration under nasal endoscopy in children >6 years old. The evaluation of duct drainage function by FDDT was considered a major endpoint (FDDT 0–1: none or a thin fluorescing marginal tear strip that persists in the conjunctival sac and normal lacrimal drainage function; FDDT 2–3: fluorescein persists in the conjunctival sac and the lacrimal drainage system is obstructed)[13].
Clinical criteria for surgery outcomes
Surgical effects were divided into cure, improvement, and invalid, according to clinical criteria. Cure was defined as lacrimal sac pore formation in the lateral nasal wall in front of the middle concha, epithelialization under endoscopic observation, no tearing or pus, FDDT=0, and smooth flush. Improvement was defined as lacrimal sac pore formation in the lateral nasal wall in front of the middle concha, epithelialization under endoscopic observation, symptom relief, FDDT=1, and flush unobstructed or pressure flush unobstructed. Invalid was defined as no relief of symptoms, FDDT=2-3, flush unsmooth or pressurized, and pore atresia. Cure and improvement were considered successful surgery, and surgery efficiency was calculated as the sum of the cure rate and the improvement rate [14].
Statistical analysis
Statistical Package for the Social Sciences (SPSS) software (SPSS Inc. Released 2008. SPSS Statistics for Windows, Version 17.0. Chicago: SPSS Inc.) was used for statistical analysis. The efficacy of preoperative treatment and the effect of type of bony nasolacrimal duct dysplasia on the cure rate were analyzed using the chi-square test, with P<0.05 representing statistical significance.