Diseases within the tear duct system can interfere with tear drainage and result in epiphora. Poor drainage with secretion retention may result in inflammation and infection. In the majority of cases, epiphora is attributed to an outflow obstruction of the nasolacrimal duct. To date, the exact etiology is not completely understood, but inflammatory alterations with stenosis at the junction between the lacrimal sac and nasolacrimal duct represent the predominant cause of acquired nasolacrimal duct obstruction. Iatrogenic damage may also result in postoperative epiphora.
As conservative care is usually ineffective, surgical procedures are the treatment of choice for distal lacrimal system pathology. Topographically there is a close proximity of the lacrimal sac and nasolacrimal duct to the nasal cavity and the paranasal sinuses, so that localized pathologic changes can also influence the tear drainage ( Box 14.1 ).
Chronic polypous rhinosinusitis
Dacryolithiasis by infections (e.g., Chlamydia, herpes, Actinomycetes )
Systemic vascular diseases (e.g., Wegener disease, sarcoidosis)
Trauma (midfacial fracture, injury of the tear drainage pathway as the result of surgical interventions; e.g., osteotomy in rhinoplasty or maxillary sinus surgery)
Tumors in the area of the tear ducts, the nasal cavity, or the paranasal sinuses
The history of surgical interventions of the lacrimal system dates back to antiquity. Modern surgical techniques were developed more than 100 years ago with the description of external dacryocystorhinostomy (DCR) by the Italian rhinologist A. Toti in 1904 and Caldwell’s proposal of endonasal DCR. Since then both methods have been competitively applied and further modified. Which method results in better outcomes is controversially discussed in the current literature. External DCR is a well-established procedure performed since the early 20th century with stable outcomes between 90% and 95% in the best hands. After Caldwell’s first description of endoscopic DCR, surgeons discovered this technique again about three decades ago. Despite significant technical progress, these early attempts to perform endoscopic DCR were not as successful as the external approach, with success ranging from 55% to 90%.
Various studies showed that the main reason for unsuccessful surgery is creating an opening in the lacrimal duct that is too small. Recent publications have shown that only a significant endoscopic resection of the lacrimal bone and the frontal process of maxilla with exposure of the entire lacrimal sac guarantees success rates equivalent to external approaches. In contrast, laser DCR allows creation of only a small ostia and has significantly lower success rates. A crucial factor contributing to success has been the understanding of the endoscopic anatomy of the lacrimal sac. Initially it was assumed that the sac extends only slightly beyond the level of the axilla of the middle turbinate ( Fig. 14.1 ). However, imaging procedures revealed that it extends significantly above the insertion of the middle turbinate (about 8 mm above the axilla). Various clinical and cadaveric studies further elucidated intranasal anatomy of the lacrimal sac in relation to other structures on the lateral nasal wall, which led to safer and more effective surgical techniques. The accurate definition of the exact intranasal position of the lacrimal sac was an essential step toward successful endoscopic DCR. The second important factor was wide marsupialization of the completely exposed sac with approximation of the lacrimal and nasal mucosa that allowed the sac to heal without granulation tissue and subsequent scarring. As a result, a novel powered endoscopic DCR approach was developed.
Endoscopic DCR directly communicates the lacrimal sac with the nasal cavity. Evaluation of the exact site of tear flow impairment is crucial to guarantee successful outcome of DCR, as proximal lacrimal blockage needs to be separately addressed. A stenosis, obstruction, or aplasia of the canaliculus or an occlusion of the lacrimal punctum is a more complex problem to solve and identifying this before surgery allows the patient to understand the likely success rate of the surgery and will change the surgical procedure performed. Therefore evaluation of the site of obstruction is very important before surgery. It is important to assess both the lacrimal system and the nasal cavity. Nasal endoscopy can identify inflammatory or infectious diseases, tumors, foreign body, or scarring or abnormality of the inferior turbinate. It can also identify the need to perform a septoplasty if the septum is significantly deviated and will obstruct surgical access. Next the lacrimal system is assessed. The punctum is dilated with a dilator and then the Bowman lacrimal probe (Integra LifeSciences, Cincinnati, OH) is used to assess the patency of the inferior and common canaliculus. As the probe is passed along the canaliculus, it enters the lacrimal sac and hits up against the side wall of the sac, resulting in a hard stop. This indicates patency of the canaliculus. If the probe stops before a hard stop is encountered, this is called a soft stop and usually indicates stenosis or obstruction of the canaliculus. These tests can be augmented by the Jones tests. A Jones I test is performed by injecting saline solution into the inferior canaliculus. If the nasolacrimal drainage pathway is patent, the saline solution will flow freely into the nose and then the nasopharynx. Checking for reflux via the superior or inferior canaliculus further elucidates the site of lacrimal path obstruction. Reflux through the irrigated punctum occurs when the canaliculus is stenosed (soft stop). Reflux through the upper punctum indicates obstruction of the nasolacrimal duct. The Jones II test is performed by injecting fluorescein-stained saline solution into the lacrimal system and then passing an endoscope into the nose to assess if there is fluorescein-stained saline solution in the nasal cavity.
Imaging: Dacrocystogram and Lacrimal Scintillography
Dacryocystography (DCG) is a diagnostic test for imaging the lacrimal apparatus. Contrast is injected into the lacrimal system, outlining the canaliculi and sac, and thereby identifying the site of obstruction. Dilation of the lacrimal sac often indicates a complete obstruction of the nasolacrimal duct. If the common canaliculus is obstructed, contrast agent will not fill the lacrimal sac. If the contrast agent passes easily into the nasolacrimal duct and nasal cavity, this indicates a functional obstruction. DCG is not an assessment of function of the lacrimal system as the dye is injected under pressure. To assess function, lacrimal scintillography is performed where a radioisotope is placed in the conjunctival fornix and its passage through the lacrimal system is assessed. This test is best used to ascertain function when DCG shows that the lacrimal system is patent. Failure of the isotope to penetrate the nasal cavity indicates a functional obstruction. A complete examination of the entire lacrimal system is mandatory to obtain a correct diagnosis and indication for surgery.
The patient should be positioned prone with the head neutral, the nasal cavity decongested, and the mucosa infiltrated with local anesthesia. A slow pulse rate and mild hypotension improves surgical visibility substantially.
Surgical access is determined by the position of the septum; any deviation of the septum that obstructs access to the lacrimal area needs to be addressed with an endoscopic septoplasty. Other anatomic obstructions such as nasal polyposis or a pneumatized middle turbinate should also be addressed.
Exposure of the lacrimal sac begins with a horizontal incision ( Fig. 14.2 ) made with a No. 15 scalpel blade 8 to 10 mm above and 10 mm anterior to the axilla. The superior incision is about 3 mm posterior to the insertion of the middle turbinate and extends 10 mm toward the frontal process of the maxilla. The second vertical incision is made 10 mm anterior toward the uncinate process and ends at the insertion of the inferior turbinate. The inferior horizontal incision starts at the uncinate joining the vertical incision. This flap is elevated with a suction Freer elevator (Martin, Tutligen, Germany) under visualization with a 30-degree endoscope. During flap elevation care should be taken to keep the elevator in the subperiosteal plane with the tip of the elevator in contact with the bone, especially as the frontal process of the maxilla dips away from the surgeon as the uncinate insertion is approached ( Fig. 14.3 ). The orbit is located posterior to the lacrimal bone and the underlying sac and behind the insertion of the uncinate and should never need to be exposed. The most important landmark is the junction of the hard bone of the frontal process of the maxilla and the soft lacrimal bone. This junction is best identified just above the insertion of the inferior turbinate. The lacrimal bone can then be flaked away with a round knife, exposing the posteroinferior part of the lacrimal sac (see Fig. 14.3 ).
During removal of the lacrimal bone, the uncinate process should be kept intact, protecting the lamina papyracea. After removal of the lacrimal bone, the frontal process is removed with a Hajek-Koffler punch (Integra LifeSciences). Especially with the first few bites of the punch, it is important to open the jaws after each bite to avoid any inadvertent sac injury, as the sac wall often can be pinched by the punch against the bone of the frontal process. It is also useful to push the sac with the tip of the punch before the jaws are closed to grip the bone. As the bone is removed superiorly, it thickens until it is no longer possible to grip the bone with the punch. At this stage, the punch is replaced by a 25-degree curved 2.5-mm rough diamond burr (Medtronic ENT; Minneapolis, MN). The drill is used to continue exposure of the sac up to the superior border of the mucosal flap. When the burr is used, caution is needed to stay on the junction between the bone and the sac and not to let the burr slip under the edge of the bone, as this will result in the burr eroding the sac wall with a resultant hole in the sac.
As the bone is removed above the axilla of the middle turbinate, the agger nasi cell is exposed. The bone is removed from around the lacrimal sac until the sac stands proud of the lateral wall of the nose ( Fig. 14.4 ). This allows the sac to be marsupialized into the lateral wall with the flaps lying flat on the lateral wall. To open the sac, a lacrimal probe is placed through the inferior canaliculus into the sac. The tip of the probe should be clearly visible behind the mucosa of the sac. If the tip of the probe is not clearly seen, then it is likely that the probe is still at the junction of the common canaliculus and the sac and not in the sac; cutting down onto the probe in this position can result in damage to the common canaliculus. With the probe clearly visible through the mucosa of the tented sac wall, a vertical incision is made with a DCR mini–spear knife (Integra LifeSciences). The sac is opened from top to bottom. To create an anterior flap, the mini–sickle knife (Integra LifeSciences) is used to make horizontal incisions superiorly and inferiorly to allow the anterior flap to be rolled out and to sit up against the frontal process of the maxilla without any tension. A Bellucci scissors (Integra LifeSciences) is used to make superior and inferior cuts in the posterior flap to allow this flap to be rolled posteriorly with resultant complete marsupialization of the sac into the lateral nasal wall ( Fig. 14.5 ).