A DCR is the treatment of choice for most patients with acquired NLDO. Surgical indications include recurrent dacryocystitis, chronic mucoid reflux, painful distention of the lacrimal sac, and bothersome epiphora. For patients with dacryocystitis, active infection should be treated, if possible, before DCR is performed.
Although there are many variations in surgical techniques, all of them create an anastomosis between the lacrimal sac and the nasal cavity through a bony ostium. One significant distinction between techniques is whether the surgeon uses an internal (intranasal) approach or the more traditional external (transcutaneous) approach. In both approaches, bicanalicular lacrimal stenting is usually performed at the end of the procedure.
Recent data indicate similar success rates for the 2 approaches. The advantages of an internal (endonasal) DCR include lack of a visible scar, a shorter recovery period, and less discomfort. An external DCR may allow better exposure for management of canalicular stenosis, unexpected neoplasm, or dacryoliths.
DCR can be performed under general anesthesia or local anesthesia with intravenous sedation. Intraoperative hemostasis can be enhanced by preoperative injection of lidocaine with epinephrine into the medial canthal soft tissues and by the use of intranasally injected anesthetic and nasal packing with vasoconstrictive agents (eg, oxymetazoline hydrochloride, phenylephrine, epinephrine, or cocaine hydrochloride). In external DCR (Fig 15-21), the skin incision should be made so as to avoid the angular blood vessels and prevent wound contractures leading to epicanthal folds. The osteotomy adjacent to the medial wall of the lacrimal sac can be created with a hemostat, rongeur, trephine, or drill. An anterior ethmoidal air cell may require removal to properly drain into the nasal cavity. A large osteotomy site facilitates the formation of posterior and anterior mucosal flaps from both the lacrimal sac and the nasal mucosa. Minimizing trauma to the common internal ostium of the canaliculi into the sac is important when creating the lacrimal sac flaps, to avoid scarring and subsequent failure of the surgery. Suturing of the corresponding posterior flaps and anterior flaps is common, but sometimes only anterior flaps are anastomosed.
Figure 15-21 External dacryocystorhinostomy (DCR). A, The incision is marked 10 mm from the medial canthus, starting just above the medial canthal tendon and extending inferiorly. B, Bone from the lacrimal fossa and anterior lacrimal crest has been resected. Flaps have been fashioned in the nasal mucosa. A lacrimal probe extends through an incision in the lacrimal sac. C, The anterior lacrimal sac flap is sutured to the anterior nasal mucosal flap after a stent is placed. D, Final position of the stent following closure of the skin incision.
(Illustration by Mark Miller.)
Endonasal DCR consists of removal of the nasal mucosa over the area corresponding to the nasolacrimal sac and duct (Fig 15-22), followed by an osteotomy to remove the frontal process of the maxillary bone and the lacrimal bone covering the lacrimal sac (Video 15-3). To allow proper exposure of the lacrimal sac, the surgeon may also need to remove the uncinate process or an anteriorly located ethmoidal air cell. The lacrimal sac is then opened, and the medial wall of the sac is removed, marsupializing the sac into the nose. Careful selection of patients with an adequate nasal cavity is crucial for success, and the surgeon should be prepared to modify the nasal anatomy for better exposure and access (eg, by performing nasal septoplasty). Several variations of endonasal DCR exist, including direct visualization or visualization with the use of an endoscope (endoscopic DCR). Some surgeons use a fiber-optic probe passed through a canaliculus to transilluminate the lacrimal sac.
Endonasal dacryocystorhinostomy. Courtesy of Bobby S. Korn, MD, PhD.
Figure 15-22 Endonasal DCR. A, Posterior incision behind the intracanalicular transilluminator (white arrow), above the inferior turbinate (black arrow), and just anterior to the insertion of the middle turbinate (asterisk).B, Frontal process of the maxilla after removal of nasal mucosa (arrow).C, Removal of the frontal process of the maxilla with rongeurs. D, The lacrimal sac has been opened (arrow), and the transilluminator can be seen in the nose.
(Courtesy of François Codère, MD.)
Figure 15-23 Sump syndrome. A, Sump syndrome resulting from inadequate superior bone removal during dacryocystorhinostomy. B, Treatment involves removing additional bone inferiorly.
(Illustration by Cat N. Burkat, MD.)
Although DCRs are successful in most patients, failures do occur. DCR failures may be caused by fibrosis and occlusion of the osteotomy, common canalicular obstruction, incomplete opening of the inferior lacrimal sac causing a sump syndrome (Fig 15-23A), or inappropriate placement or size of the bony ostium. Another cause of failure is iatrogenic: If the mucosa of the nasal septum is damaged during surgery, a bridge forms between the ostium and the scar of the septum. Treatment is aimed toward removal of this residual inferior bone through an external or endonasal approach (Fig 15-23B). The outcome of the DCR is also influenced by other factors, including the patient’s history of trauma, coexisting autoimmune inflammatory disease, the presence of active dacryocystitis, the development of postoperative infection, or hypersensitivity or foreign body reactions to the stent. When an initial DCR fails, some surgeons apply topical mitomycin to the surgical site during reoperation. This potent antiproliferative alkylating agent helps prevent fibrosis at the osteotomy site.
Endoscopic lacrimal duct recanalization
The use of a microendoscope allows for exploration and direct visualization of NLDOs, as well as focal excision and reconstruction of the obstruction, and has had success rates as high as those for DCR. The use of this technology is not widespread, and further study will help define its role in the treatment of NLDO.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.