Nasal endoscopic lacrimal sac rhinostomy
Zhang Liqiang
Department of Otolaryngology, Qilu Hospital, Shandong University, No. 107, West Culture Road, Jinan, 250012, China
Abstract In this paper, the anatomy of the lacrimal system, preoperative evaluation, surgical approach, postoperative outcome and its influencing factors are presented in terms of nasal endoscopic lacrimal sac rhinostomy. The upper border of the lacrimal sac can reach up to an average of 8 mm above the anterior dome of the middle turbinate. the selection of surgical cases needs to exclude lesions of the tear dots and lacrimal ducts, otherwise the success rate of the operation will be affected. The bone window should be opened as wide as possible to prevent atresia of the postoperative lacrimal sac stoma. Reducing trauma and bone exposure through a series of measures helps to make the incision heal as quickly as possible. Precise operation and accurate positioning are important measures to reduce surgical complications. Zhang Liqiang, Department of Otolaryngology, Qilu Hospital, Shandong University
Keywords nasal endoscopy, dacryocystitis, surgical procedure
In recent years, with the development of nasal endoscopy technology, the technique has been extended to the treatment of more and more nasal and ocular related diseases. Previously, surgical treatment of chronic lacrimal sacculitis was mainly performed by ophthalmologists from the external nasal route, which left skin incision scars on the patient’s face, and, because the anastomosis between the lacrimal sac and the nasal mucosa was not clearly exposed when the surgery was performed from the external nasal incision, sometimes the stoma might pass into the anterior group of septal sinuses. Also, in patients with combined sinusitis, the success rate of the surgery is affected because the treatment cannot be performed at the same time. The introduction of nasal endoscopy technology has made it easy to perform lacrimal sac surgery under direct vision, simplifying the surgical operation and improving the postoperative results. In this paper, issues related to nasal endoscopic lacrimal sac rhinostomy are presented in conjunction with domestic and international literature.
I. Anatomy of the application of nasal endoscopic lacrimal sac rhinostomy
Tears are mainly secreted by the lacrimal gland located in the supraorbital crypt. A thin tear film consisting of a deep mucus layer and a superficial oil layer forms a protective film over the exposed surface of the eye. The tears converge at the inner lid margin where they are drained into the lacrimal ducts through the openings of the upper and lower tear ducts. The beginning 2 mm of the lacrimal duct is perpendicular to the lid margin, while its distal 8 mm is parallel to the eyelid, descending deeper into the medial canthal ligament and finally into the lacrimal sac. In most cases, the upper and lower lacrimal ducts converge to form the common lacrimal duct before entering the lacrimal sac.
The lacrimal sac is located in an ovoid lacrimal fossa, which is approximately 15 mm high and 10 mm wide, and the thicker bone of the frontal process of the maxilla forms the anterior lacrimal crest, which is the anterior border of the lacrimal fossa. In contrast, the thin lacrimal bone forms the posterior lacrimal crest, which is the posterior border of the lacrimal sac fossa. The maxillary frontal process fuses with the lacrimal bone at the longitudinal bone p that crosses the lacrimal sac vertically.
The lower end of the lacrimal sac tapers as it enters the bony nasolacrimal duct composed of the maxilla, lacrimal bone, and inferior turbinate. The nasolacrimal duct travels approximately 12 mm within the bony duct and then joins a membranous nasolacrimal duct with an internal length of approximately 5 mm located below the inferior turbinate and opening in the inferior nasal canal. The nasolacrimal duct opens at the junction of the anterior middle third of the inferior nasal canal, about 8 mm from the anterior inferior turbinate and about 29 mm from the anterior nasal crest, which is often covered by a mucosal flap called the Hasner valve, which helps prevent nasal secretion reflux.
When viewed from within the nasal cavity, the lacrimal sac lies beneath the bony lateral wall of the nasal cavity anterior to the middle turbinate, and its posterior border often extends below the middle turbinate and behind the maxillary line. Regarding the superior border of the lacrimal sac, early studies suggested that it extends slightly above the attachment of the middle turbinate to the lateral wall of the nasal cavity. Recent studies have shown that the upper border of the lacrimal sac can reach an average of 8 mm above the anterior turbinate of the middle turbinate, so that during endoscopic lacrimal sac rhinostomy, the nasal mucosal incision and the removal of bone need to be extended upward accordingly. Otherwise, it is not easy to open all the lacrimal sacs, which affects the success rate of the operation. The frontal process of the maxilla is in front of the facial soft tissues, and after removing the bones of the frontal process of the maxilla during surgery, if a small tear sac is encountered or there is a scar around it, it will be somewhat difficult to locate the tear sac, and sometimes the facial soft tissues can be mistaken for the tear sac, causing infection of the facial soft tissues or subcutaneous petechial hemorrhage of the facial skin.
II. Preoperative evaluation and indications for surgery
All patients require a detailed preoperative evaluation by an ophthalmologist to rule out other conditions that cause excessive tearing, commonly: narrowing or occlusion of the lacrimal duct scar, narrowing or occlusion of the lacrimal duct, conjunctivitis or blepharitis, and misalignment of the eyelid, the latter of which can cause the lacrimal duct to be out of its original position and thus make collection of tears difficult. Probing inward with a probe through the lacrimal dots, if the probe is obstructed softly, there may be narrowing or obstruction of the lacrimal duct, if the probe is obstructed hardly, it means that the probe has reached the medial bony wall of the lacrimal sac, suggesting that the lacrimal duct is patent. Evaluation of the lacrimal sac requires lacrimal sac angiography and CT. The lacrimal sac angiogram reflects the size of the lacrimal sac, while the CT exam reflects the thickness of the bone surrounding the lacrimal sac, the size of the bony lacrimal sac wall, and the presence of combined chronic sinusitis, which is an important reference for the surgeon to accurately assess the potential difficulties encountered during surgery, especially for those with a history of prior sinus surgery. Once the lacrimal sac evaluation is complete, the presence of nasolacrimal duct obstruction is then examined by the Jones dye test. It is important to note that some patients may not have an anatomic obstruction of the lacrimal system, but rather a functional obstruction, and an isotope scan can help confirm a functional obstruction when symptomatic patients have a normal lacrimal sac imaging. If the isotope scan confirms the absence of isotope entry in the nasal cavity, functional nasolacrimal duct obstruction is definitive. Endonasal endoscopic nasolacrimal sacculostomy is less effective in these patients than in those with pure anatomic obstruction.
Patients also require a preoperative nasal endoscopy to assess for the presence of a deviated septum, enlarged middle turbinate, nasal polyps, sinusitis, and nasal tumors. These can be treated together with the lacrimal sac surgery to ensure the success rate of the lacrimal sac surgery.
Taking into account the above factors, the indications for surgery with nasal endoscopic lacrimal sac rhinostomy are: chronic dacryocystitis, lacrimal sac mucus cysts, and lacrimal sac stones. In addition, lacrimal sac rhinostomy is sometimes feasible after removal of the nasolacrimal duct for the removal of nasal tumors to prevent postoperative dacryocystitis. Contraindications are: narrow and obstructed lacrimal ducts, narrow and obstructed tear ducts and acute inflammation of the nasal cavity and sinuses.
III. Surgical methods
1 Anesthesia: general anesthesia or local anesthesia is acceptable.
2 Mucosal flap incision: the first horizontal incision is 8-10 mm above the anterior turbinate of the middle turbinate, the entry point is located at the anterior turbinate of the middle turbinate about 3 mm backward, the incision is about 10 mm forward and cut to the frontal process of the maxilla, then the blade turns longitudinal and makes a vertical incision to 2/3 of the vertical height of the middle turbinate, the incision terminates above the insertion of the inferior turbinate into the lateral wall of the nasal cavity, the blade turns transverse again, the incision below begins at the hook The blade is then turned transversely and the lower incision begins at the hook attachment and is connected forward to the vertical incision. The mucosal flap is lifted with the striker, which is placed against the bone surface and slides along the prominence of the frontal process of the maxilla. Touching the bone at this site identifies the soft lacrimal bone with the hard maxillary frontal process. In this way, a mucosal flap with a tip at the hooked process is formed. The mucosal flap can be trimmed to cover the exposed bone surface at the completion of the lacrimal sac stoma. The mucosal flap may also be removed directly.
3 Excision of the bone method: the thinner lacrimal bone is anterior to the attachment of the hooked process, approximately 2-5 mm wide, and the surgical area is bounded posteriorly by the hooked process. The softer tear bone is peeled off and removed from the posterior inferior border of the lacrimal sac with a circular knife, or if difficulty is encountered, the maxillary frontal process needs to be removed before peeling the tear bone. The lower part of the maxillary frontal process is removed with a maxillary sinus bite forceps, the tip of which is pushed outward over the removed tear sac. As the occlusal forceps approach the tear sac to remove the bone, care is taken not to pinch the wall of the sac. After removal of the maxillary frontal process, the anterior inferior portion of the lacrimal sac is exposed. The occlusal forceps continue to remove the bone as far upward as possible until the bone is so thick that the forceps cannot operate. In this position, a coarse gold drill is used to remove the bone below the upper mucosal cut edge. The light contact of the coarse gold drill with the lacrimal sac wall will not damage the lacrimal sac, but significant pressure of the drill on the lacrimal sac will cause damage. The bone is removed until the entire lacrimal sac is completely exposed, and the lacrimal sac should be located in a projection on the lateral nasal wall so that when the lacrimal sac is incised and the mucosal flap is turned out, it can lay flat on the lateral nasal wall. The greater the extent of bone removal, the easier it is for the lacrimal sac mucosal flap to lay flat on the lateral nasal wall, so that the lacrimal sac is creating a pocket on the lateral nasal wall rather than just a window in the sac wall.
4 Tear sac treatment The lower tear dots are dilated with a tear duct dilator and then the tear sac probe is inserted into the tear sac and as the probe moves up and down in the tear sac, its tip can be seen moving behind the tear sac wall to confirm that the probe is indeed in the tear sac. If the probe tip does not move behind the thin wall of the lacrimal sac then this indicates that the probe may still be in the union of the common duct and the lacrimal sac and that the lateral wall of the lacrimal sac may be pushed against the medial wall and thus the medial wall may move but the probe tip is not visible. After the probe head is seen through the wall of the capsule, the lacrimal sac is incised from the top to the bottom by pressing the tip of the sickle-shaped knife into the jacked-up capsule wall at the lower edge of the probe, forming two longitudinal mucosal flaps anteriorly and posteriorly, and then transverse incisions in the upper and lower rows of the flap to facilitate better attachment of the mucosal flap to the lateral wall of the nasal cavity. The lacrimal sac should be opened to the bottom to prevent the formation of a water reservoir at the bottom, causing mucus to accumulate and block the stoma opening upward. The tip of the lacrimal sac should be opened upward to the point where the opening of the common lacrimal duct into the lacrimal sac can be easily seen. Some authors also advocate that when the lacrimal sac is incised longitudinally, the lacrimal sac can be made into an anterior mucosal flap or posterior mucosal flap as large as possible and then attached to the trauma on the lateral wall of the nasal cavity. It is usually easier to do the posterior mucosal flap.
If the lacrimal sac is large and there is no obvious edema or polyps on the mucosal surface of the lacrimal sac, the lacrimal sac mucosal flap can be well laid on the lateral wall of the nasal cavity, and the mucosal flap can be fixed properly with hemostatic damask, otocerebrosides or silver clips, it is not necessary to place a dilatation tube. However, for small lacrimal sacs or those undergoing revision surgery, a dilating tube should be placed through the lacrimal duct to expand the lacrimal sac incision during the postoperative recovery period.
6 Caulking Evaluate the exposed bone around the lacrimal sac, reposition the mucosal flap of the lateral nasal wall above the open lacrimal sac, trim the mucosal flap so that it covers the bone surface, and make the mucosal flap adhere to the lacrimal sac mucosal flap and nasal mucosa to facilitate healing and to reduce granulation and scar formation. The nasal cavity can be gently filled with hemostatic damask.
7 Postoperative care Nasal spray with saline is started 3-4 hours after surgery, which can clean up the residual blood crust and keep the nasal cavity moist. External nasal spray hormone can be used in the nasal cavity, and oral prednisone can be taken appropriately to reduce scar formation. Dot the eyes with antibiotics for 3 weeks. Apply antibiotics for 5 days. Postoperative review once a week for 1 month and once a month thereafter until healing. Nasal endoscopy to clean up local granulomatous blood crust. Tear duct irrigation is performed once a week, and the tear duct dilator tube is removed after 4 weeks to check the function of the tear sac and to clamp off any granulomatous hyperplasia. In patients undergoing revision surgery, the placement of the dilator tube may be extended to 6 months. Healing is not considered until 18 months after surgery.
If it is not easy to determine where the anterior border of the previous surgical window is, the maxillary frontal process can be found, and the frontal process can be moved forward and backward until the connection between bone and soft tissue is found, at which point the soft of the lacrimal sac opening. After the mucosal incision is made, the mucosal flap is then separated, as the mucosa may be connected to the lacrimal sac below with connective tissue that can be separated with a sharp scalpel. After the mucosal flap is separated, the bony supplement is then excised. A probe is placed into the lacrimal sac via the lacrimal duct, which is visible endoscopically to hold up the soft tissue of the lateral nasal wall. The mucosa surrounding the lacrimal sac is excised so that the intranasal opening of the lacrimal sac is at least 1 cm in diameter. If the lacrimal sac is already open, the lacrimal sac probe tip is exposed, and then the scar around the probe is removed using the probe as a guide to place the dilator tube.
IV. Advantages of the nasal endoscopic technique and issues to be noted during the procedure
Previously, when ophthalmologists performed extra-nasal lacrimal sac nasal anastomosis, they did not perform the procedure if inflammation was present in the sinuses to prevent incisional infection and postoperative restenosis of the stoma. Nasal endoscopic surgical techniques allow simultaneous management of both lacrimal sac disease and sinus inflammation. Nasal endoscopic performance of lacrimal sac rhinostomy not only avoids facial scarring, but also helps to identify and correct common intranasal causes of surgical failure such as adhesions, middle turbinate hypertrophy, and septal sinus disease. The lateral wall of the lacrimal sac is effective in preventing the spread of sinus infection to the orbit because it acts as an anatomical barrier. About 15% of patients require concurrent sinus surgery at the time of lacrimal sac rhinostomy, and 47% of patients require concurrent septal correction. In addition, because of the proximity of the anterior turbinate of the middle turbinate to the skull base in children, there is a risk of damage to the skull base when the bone is removed from the surface of the lacrimal sac, and adequate attention should be paid during surgery.
V. Postoperative results and factors affecting the outcome
The criteria for a successful endoscopic lacrimal sac rhinostomy are that the patient’s symptoms disappear and that the lacrimal sac is well opened on endoscopic examination. The postoperative outcome is related to the etiology of the dacryocystitis, with a success rate of up to 95% in patients with anatomical lacrimal obstruction and 81% in patients with functional lacrimal obstruction. Nasal endoscopy showed that the anatomical obstruction factor was resolved in 95% of the patients with functional obstruction, and the patients were still symptomatic, but with significant improvement over the preoperative period. In lacrimal sac imaging, the success rate was 82% in those with normal or enlarged tear sacs and only 29% in those with scarred tear sacs. It is worth noting that tear collection function is closely related to the siphoning function of the lacrimal ducts and the lacrimal sac, and that the siphoning function of the lacrimal sac is compromised after lacrimal sac rhinostomy, despite the complete opening of the lacrimal ducts anatomically, which may be one of the reasons for the poor outcome in some patients. The effectiveness of topical nasal steroids in some cases of lacrimal sac mucosal edema has not been verified. No studies have been seen regarding whether there are sufficient steroid hormone receptors distributed on the mucosal surface of the lacrimal sac. More basic research is needed on how to inhibit the proliferation of bone and fibrous tissue around the lacrimal sac, which may proliferate more during revision surgery. Clinical experience has shown that those with multiple failed surgeries are highly likely to have lacrimal duct scarring, which requires the assistance of an ophthalmologist to manage.
VI. Surgical complications
Complications of nasal endoscopic lacrimal sac rhinostomy are uncommon. There is a risk of damage to the cardboard exposing the orbital fat during removal of the bone, and care should be taken not to excessively harass the exposed orbital fat to prevent intraorbital complications, which are less likely to enter the orbit as long as the operation is performed anterior to the hooked process. The incidence of postoperative adhesions is relatively high, mainly between the lateral wall of the nasal cavity and the middle turbinate or nasal septum. The deviated nasal septum should be actively corrected, and in some cases, the anterior end of the middle turbinate can be removed to prevent it from being too close to the opening of the lacrimal sac, which can also reduce adhesions. In patients with small lacrimal sacs, it is sometimes difficult to position the lacrimal sac and it is possible to damage the soft tissues of the face by leaning too far forward. A lacrimal probe can be useful at this time.