Conjunctivo-canaliculo-cysto-rhinostomy:repurposing an orbital mucocele as a neo-lacrimal conduit in congenital lacrimal agenesisOA

Background:Congenital absence of the lacrimal sac and nasolacrimal duct(congenital lacrimal drainage agenesis)brings special diagnostic and surgical challenges,especially when patients have persistent epiphora and cystic change in the inferomedial orbit.Since conventional dacryocystorhinostomy(DCR)needs a definable lacrimal sac to make a new drainage ostium into the nasal cavity,standard DCR may not be possible when there is true lacrimal sac/nasolacrimal duct agenesis.In this case,we need a reconstructive strategy that can restore tear outflow and also respect the patient’s congenital anatomy.We report a reconstructive approach-conjunctivo-canaliculo-cystorhinostomy(CCCR).When the native lacrimal sac is absent,it reuses an existing inferomedial orbital cystic cavity as a new lacrimal conduit to re-establish drainage.Methods:This study is a case report of a single patient from a tertiary ophthalmic center.A 26-year-old woman with bilateral lacrimal agenesis had epiphora and a progressive inferomedial orbital cyst.Clinical examination showed a palpable,cystic,and non-tender mass in inferomedial orbital.Lacrimal assessment showed that the lacrimal drainage pathway was congenitally absent.Orbital computed tomography(CT)confirmed the congenital absence of the lacrimal sac and nasolacrimal duct.Orbital magnetic resonance imaging(MRI)showed a well-defined inferomedial right orbital cystic lesion next to the expected lacrimal fossa region.Whole-exome sequencing did not find pathogenic variants related to lacrimal dysgenesis.The patient had CCCR under general anaesthesia using a combined external and endoscopic approach.CCCR included an external conjunctivo-canaliculo-cystic microanastomosis to establish continuity between the ocular surface outflow pathway and the cystic lumen,and an endoscopic cysto-rhinostomy to create an opening from the cystic cavity into the nasal space.Temporary bicanalicular silicone stenting was used to support maturation of the reconstructed tract.Then the stent removal,and lacrimal irrigation and nasal endoscopy were used for serial postoperative assessment.Results:CCCR was completed without intraoperative complications.After the operation,the inferomedial orbital mass and epiphora disappeared.Lacrimal irrigation showed that the reconstructed drainage pathway was patent at 2 weeks and 2 months,and it remained patent at 4 months(after stent removal).Nasal endoscopy showed a stable,epithelialised ostium without stenosis,which supported long-lasting communication between the reused cystic cavity and the nasal cavity.Histopathological evaluation of the excised cyst wall confirmed that it was a benign epithelial cyst,which was suitable as a non-malignant cystic substrate suitable for use as a new lacrimal conduit in this case.Conclusions:In a patient with congenital absence of the lacrimal sac and nasolacrimal duct complicated by an inferomedial orbital cyst,CCCR-an external conjunctivo-canaliculo-cystic microanastomosis combined with endoscopic cysto-rhinostomy and temporary bicanalicular silicone stenting-successfully restored tear outflow and resolved both epiphora and the cystic mass,with sustained patency after stent removal.CCCR offers an anatomy-sparing surgical option when conventional DCR is impossible.It also shows that it is feasible to reuse an inferomedial orbital cystic cavity as a new lacrimal conduit in carefully selected cases of congenital lacrimal drainage agenesis.