Outcomes after revision endoscopic dacryocystorhinostomy (endoscopic DCR) are excellent and the preferred approach when possible.
Endoscopic DCR allows the surgeon to thoroughly evaluate the neo-ostium and address concomitant nasal pathology at the time of surgery in a minimally invasive fashion
Understanding the critical endonasal anatomic relationships is essential to successful revision endoscopic DCR
If patients have concomitant severe canalicular stenosis, conjunctivodacryocystorhinosotomy (CDCR) should be considered independently or in conjunction with endoscopic DCR
Nasolacrimal duct obstruction (NDLO) is commonly managed through dacryrocysorhinostomy (DCR). Historically, this has been performed via an external approach with excellent outcomes. Although intranasal techniques for DCR were first introduced in the early 1900s, modern endoscopic DCR was not described until 1989. After its initial introduction, endoscopic DCR acceptance was limited because of inconsistent success rates within the literature. Initially reports of poor visualization, limited understanding of intranasal anatomy, and suboptimal surgical instrumentation were cited as factors leading to inferior outcomes after endoscopic DCR compared with external DCR. However, technological advances in both videoscopic visualization and rhinologic instrumentation, in combination with a rapid growth in clinical experience, have mitigated these concerns in recent years. In fact, recent literature now demonstrates that endoscopic DCR has success comparable to external DCR. Advantages of the endoscopic approach include the avoidance of a cutaneous incision, preservation of the orbicularis oculi pump function, decreased operative time, and the ability to address concomitant intranasal pathology that may be contributing to the NLDO, such as septal deviation or nasal polyposis. Additional information about primary endoscopic DCR and management of NLDO is discussed in more detail in 13, 14 .
Causes of Dacryocystorhinostomy Failure
Regardless of the chosen approach, both external and endoscopic DCR have failure rates of up to 10%. Patients with a prior history of facial trauma, craniofacial abnormalities, or prior DCR are at greater risk for recurrence of symptoms. There are two primary categories of DCR failure: anatomic, indicating a physical obstruction; and functional, which describes patients who experience persistent symptoms of epiphora despite evidence of a patent neo-ostium on objective testing. For a complete list of common causes of failure, see Box 15.1 .
|Inappropriately placed osteotomy
|Incomplete bony removal
|Soft-tissue obstruction of the osteotomy (cicatricial ostium closure, granuloma, synechiae)
|Concomitant nasal pathology or anatomic obstruction (i.e., septal deviation, concha bullosa of the middle turbinate)
|Functional failure (lacrimal pump failure, eyelid laxity)
|Upper system/canalicular stenosis
Inadequate Bony Osteotomy
Many studies have demonstrated primary DCR failure secondary to inadequately or inappropriately placed osteotomies. When performing a DCR, it is vital that the surgeon have a thorough knowledge of the lacrimal anatomy and its relationship to nasal anatomy. Fig. 15.1 demonstrates a patient whose external DCR failed as the result of inappropriate placement of the osteotomy. The lacrimal sac rests in an ovoid fossa measuring approximately 15 × 10 mm along the maxillary line. The frontal process of the maxilla contributes the anterior half of the fossa and the thin lacrimal bone provides the posterior half. In 2000 Wormald, Kew, and Van Hasselt performed a radiographic analysis of cadavers that demonstrated that the lacrimal sac often is located higher on the lateral nasal wall than previously thought. In this study, the location of the lacrimal sac was found to extend to a mean height of 8.8 mm above the middle turbinate insertion and approximately 5.3 mm above the common canaliculus.
When placing the osteotomy, it is important that it is not only in an adequate position but also of sufficient size. One prospective study demonstrated ostium shrinkage of approximately 35%, with the majority of size change occurring in the first 4 weeks postoperatively. After 4 weeks the ostium size does not appear to change significantly. Linberg et al. were the first to endoscopically examine the size the postoperative intranasal ostium after external DCR but did not find correlation between the final and the intraoperative osteotomy size. More recent studies using internal ostium photography have shown a correlation between larger intraoperative osteotomy size and postoperative intranasal neo-ostium size. Although the overall size of the osteotomy may not directly correlate with surgical success, it is believed that osteotomy size must be sufficiently large initially to prevent complete closure with known postoperative contraction. Therefore if the initial bony osteotomy is not large enough to expose the entirety of the lacrimal fossa after the ostium contracture occurred, failure may ensue. The primary objective is adequate exposure of the common internal punctum (canaliculus).
Mucosal contracture is a common cause of DCR failure. Evaluations of failed primary DCRs, both external and endonasal, have demonstrated that approximately 50% of failures are due to cicatricial scarring of the neo-ostium ( Fig. 15.2 ). After bony osteotomy is created, the entirety of the medial wall of the lacrimal sac should be exposed and then incised sufficiently so that the entirety of the sac is marsupialized and the common canaliculus is exposed. If during this process there is excessive mucosal injury, either to the nasal or lacrimal mucosa, it could contribute to more scarring and increased ostial shrinkage. In addition, inflammation during healing could lead to the formation of granulomas or intranasal synechiae, which can contribute to ostium obstruction ( Fig. 15.3 ). Some groups advocate for apposition of nasal and lacrimal mucosa (preservation of mucosal flaps), encouraging primary wound healing and thus decreasing scar formation. It is our belief that the presence of redundant mucosa may contribute to excess scar formation in certain cases and thus should be trimmed, if present, to allow for optimized healing by secondary intention. We have found this technique of not preserving the mucosal flaps to produce comparable outcomes.
Concomitant Nasal Pathology or Anatomic Variations
It is important for the surgeon performing DCR to recognize the potential implications of intranasal pathology and anatomic variations. Abnormalities, such as a deviated septum, lateralized middle turbinate, or concha bullosa of the middle turbinate, can cause a physical obstruction of the osteotomy. In addition, if those structures have any mucosal injury at the time of primary DCR, synechiae may form, causing additional obstruction. Other nasal pathologies, such as the presence of nasal polyps, may also contribute to neo-ostium obstruction postoperatively and should be addressed at the time of DCR. Although concomitant nasal pathology contributing to anatomic failure is more common after external DCR, it may also serve as a source of failure after endoscopic DCR.
It is also important to note that normal anatomic variations may result in obstruction of the neo-ostium. In their review of 25 revision DCRs, Liang et al. evaluated the anatomic relationship of the agger nasi cell with the lacrimal fossa. They found that, when present, 95% of agger nasi cells overlap the lacrimal fossa. Similarly, Soyka, Treumann, and Schlegel noted that if this relationship is not recognized, then the neo-ostium may be partially or completely obstructed by the agger nasi, thereby causing DCR failure. In other words, failure to adequately open the agger nasi cell may lead to poorer outcomes.
Despite meticulous surgical technique, studies frequently describe a subset of patients in whom functional failure develops after both external and endoscopic DCR. Functional failure—the persistence of epiphora—despite a patent neo-ostium, is not fully understood. However, it is thought to be secondary to proximal problems with the lacrimal system, such as dysfunctional lacrimal pump mechanism, eyelid laxity, or canalicular stenosis. It is important to recognize proximal dysfunction of the lacrimal system, such as eyelid laxity, before performing DCR to limit functional failure.
Although endoscopic DCR does not disrupt the bony or soft tissues that support that lacrimal system, external DCR requires an external incision through these support systems. Damage to the peripheral fibers of the facial nerve that innervate the medial orbicularis oculi, leading to poor eyelid closure and poor lacrimal pump function, has been demonstrated after external DCR. In the study of 247 external DCRs by Vagefi et al., there was a 7.4% incidence of temporary orbicularis weakness after surgery. Eyelid laxity, punctal position, punctal size, and canalicular tortuosity or stenosis may also contribute to poor tear film drainage and functional obstruction. In addition, Lee et al. examined the endoscopic features associated with functional failure after 50 external DCRs. Their study demonstrated that, despite anatomic success, 16% of patients demonstrated functional failure. Examination of the neo-ostium shape of those with functional failure demonstrated that a neo-ostium that healed in the cavernous shape, described as a large osteotomy with preservation of the lacrimal sac, were more likely to have functional failure. They hypothesized that this remnant sac, which was not incised fully during the primary surgery, obstructed the drainage pathway.
Upper System/Canalicular Stenosis
Proximal stenosis of the canalicular system may also contribute to failure after primary DCR. It is important for surgeons to recognize proximal obstruction before performing a primary DCR because if it is present, DCR alone would not be sufficient. Instead, conjunctivodacryocystorhinostomy (CDCR) would be required to properly address the stenosis. If CDCR were not performed, either alone or in conjunction with DCR, it is likely that the patient will continue to have symptoms of epiphora postoperatively.
Proximal stenosis may also develop after primary DCR. Trauma or inflammation induced by canalicular manipulation at the time of primary DCR can contribute to the development of common canalicular obstruction. This has been noted to be a frequent cause of failure, both independently and in conjunction with ostium closure. Failure to properly identify proximal system obstruction or causes of epiphora is one of the more important causes of poor outcomes after endoscopic DCR. This highlights the need for accurate preoperative assessment and diagnostic tests.
Indications for Revision Surgery
Similar to patients presenting for primary DCR, patients with previous failed DCRs present with bothersome tearing and/or dacryocystitis. When considering revision surgery for patients in whom recurrent symptoms develop, the surgeon must carefully determine the etiology of the failure. Most of the workup is similar to that performed before primary DCR: evaluation for midfacial trauma, systemic inflammatory conditions, and abnormalities of the lacrimal system, as described in other chapters of this text. In addition, a thorough endoscopic endonasal evaluation should be completed by an otolaryngologist to assess the neo-ostium and to evaluate for concomitant nasal pathology that could be contributing to recurrence of symptoms. If chronic sinusitis is suspected, computed tomography imaging of the paranasal sinuses should be performed. Ultimately, a thorough understanding of the source of primary failure is required to drive the approach for revision surgery.
If an obstruction distal to the common canaliculus is identified, revision DCR is the best surgical option. Although revision DCR can be performed externally, endoscopic DCR, performed in a collaborative fashion with otolaryngology and ophthalmology colleagues, has distinct advantages. Endoscopic DCR allows the surgeon to directly visualize the neo-ostium under high magnification to address any intranasal pathology that has contributed to failure, such as synechiae, granulomas, or anatomic obstruction. In addition, there is no external incision or disruption of the lacrimal pump apparatus. Endoscopic DCR also has shorter operative times, decreased blood loss, and earlier rehabilitation.
It is also important to note that if patients have canalicular stenosis, DCR will likely be insufficient to address the patient’s symptoms. In cases of proximal lacrimal duct stenosis or severe common canalicular stenosis, stent placement at the time of revision DCR may be an option. However, if the stenosis is severe, the patient may benefit instead from CDCR alone or in combination with DCR. During CDCR, a Jones tube (glass tube) is placed from the tear lake at the caruncle directly into the middle meatus. This ultimately bypasses the lacrimal system, creating a new tear outflow tract.
Revision Endoscopic DCR
More detailed description of the technique for endoscopic DCR is included in other chapters in this textbook; thus we will focus on the highlights unique to revision endoscopic DCR.
Revision endoscopic DCR can be performed using either local or general anesthesia, although our preference is for it to be done with the patient under general anesthesia. The challenge in the revision setting, however, is appreciating the anatomic factors that have led to failure and then approaching them with a plan to address each of them. Most commonly this includes looking for mucosal scarring or obstruction of the neo-ostium, inadequate bone removal and exposure of the lacrimal sac, lateralization of the middle turbinate, or a residual septal deviation limiting access. Granulation tissue, such as that demonstrated in Fig. 15.4 , may be one source of neo-ostium obstruction.