Management of Pediatric Lower System Problems: Dacryocystorhinostomy

Fig. 28.1
Endonasal view-schematic rendition of the anatomy of the lacrimal fossa (LF) of the right side. The white dotted line represents the projection of the first ethmoidal cell, according to Blaylock et al. [11], onto the upper part of the inferior turbinate. The black dotted lines represent three common retrolacrimal, lacrimal, and maxillary projections. CC common canaliculus, FS frontal sinus, IT inferior turbinate, MB maxillary bone, MlS maxillo-lacrimal suture-junction between the MB and the lacrimal bone, MS maxillary sinus, MT middle turbinate, OMT opercule of the middle turbinate, UP uncinate process (Adapted from Fayet [10])

Preoperative Evaluation

Preoperative evaluation should include a thorough history of the nature of the epiphora, including antibiotics used for prior infections, prior probing procedures, or stenting treatments (silicone stent or balloon catheter). Additionally, any history of seasonal allergies, previous episodes of conjunctivitis, upper respiratory or sinus infections, or prior trauma should be explored. Further medical history should be gathered concerning bleeding diathesis, related congenital syndromes, anesthetic problems, or cardiac anomalies requiring perioperative antibiotic treatment.

In addition to the standard ocular exam, which includes screening for anatomical abnormalities, strabismus, or amblyopia, the in-office evaluation should include a dye disappearance test to grade the degree of obstruction and uncover any previously unnoticed drainage problems on the uninvolved side. Slit lamp examination is used to confirm the presence of the eyelid punctum and to rule out the presence of a fistula. If a patient is old enough to tolerate it, an in-office probing and irrigation can be performed. This can be accomplished with a standard 23-gauge lacrimal cannula or, more ideally, with a disposable 25-gauge lacrimal cannula (Storz, USA). Imaging studies of the orbits and face may be ordered if there is a concern regarding a history of prior trauma or the presence of a craniofacial syndrome.

Finally, a well-informed family is crucial to a positive outcome. Fully discussing pre- and postoperative expectations, including antibiotic treatment, bloody drainage, care and monitoring of silicone tubing, and suture removal, can allay the fears of most families. In the unlikely event that intraoperative findings necessitate a different surgical plan (such as upper system blockage requiring a Pyrex tube), prior discussion with the child’s family will best prepare them for the most appropriate treatment.

External Versus Endoscopic Approach to Dacryocystorhinostomy

The decision on the surgical approach chosen for dacryocystorhinostomy depends on a number of factors, including the age of the patient, the intranasal anatomy, and the availability of specialized equipment. The main disadvantage of the external DCR is the cutaneous scar, but for the occasional lacrimal surgeon, the external DCR is technically less demanding: Hemorrhage can be controlled more easily, and a relatively larger osteotomy can be created, which may be especially important in pediatric patients because of the increased rate of bone growth and possible closure of the osteotomy [12, 13]. When performing a DCR through an external incision, it is easier to obtain pathological specimens of the lacrimal sac, although this is rarely critical in children. In addition, direct anastomosis of the anterior and posterior lacrimal flaps is readily accomplished with an external approach. This is not typically attempted in an endonasal approach.

The main advantage of endoscopic dacryocystorhinostomy is the absence of a small facial scar. However, endoscopic dacryocystorhinostomy in children is especially demanding because of the small intranasal space. Because of this, pediatric sinuscopes (0° 2.8-mm diameter) are frequently utilized, which presents further difficulties in the visualization of the intranasal area. Microendoscopes have also been designed for transcanalicular lacrimal surgery [14]. Another major advantage of the endoscopic approach is that it removes a major intra- and postoperative source of bleeding – the orbicularis muscle.

With the advent of an ultrasonic bone aspirator as well as nasal mucosal microdebriders, the endoscopic endonasal approach to DCR surgery has become an elegant procedure with similar surgical results when compared to the external approach. Fayet et al. published his results of a very large series of endoscopic DCR. This series was in adult patients with an average age of 66 with a success rate of 94% in 300 cases [10]. Jung et al. reported their success in 1083 consecutive cases of 92.7% in patients with an average age of 57 [15]. In both of these series, the surgical rhinostomy was created with Kerrison rongeurs . In our series of endoscopic endonasal DCR performed with an ultrasonic bone aspirator (Stryker, USA) in 71 consecutive pediatric cases (47 subjects) including those with Down syndrome, we had a success rate of 62/71 cases (87.3%). This rate improves to 58/62 (93.5%) when patients with Down syndrome are removed [16]. A literature review enDCR publications in pediatric patients identified 14 studies, 393 procedures overall. The overall success rate for all of these publications was 87% [17].

Stent Nomenclature

Silicone stents are repeating polymers of siloxane. Nasolacrimal stents are often actually manufactured as tubes; however, in nasolacrimal stent design, tears do not pass through the tube lumen. Thus, the term tube is misleading and the word stent is more representative. Silastic is a silicone tubing trademarked in 1948 by Dow Corning. Most stents used today in nasolacrimal surgery are now made with silicone that is not actually Silastic but instead generic silicone tubing. We are thus dropping the term Silastic tubing as it is now dated and misleading: Stents are tubes, but tears do not pass through them. Stents are made of silicone but usually not Silastic silicone.

External Dacryocystorhinostomy in Children

It is especially important that blood loss be minimized in the pediatric age group. A 20–40-mL blood loss in a 1-year-old child is a much higher percentage of total blood volume than it would in an adult. Although dacryocystorhinostomy in adults is often performed using local anesthesia with sedation, it is generally not possible to use local anesthesia alone in young children. General endotracheal anesthesia is preferred, especially in the very young child. It is helpful to have an anesthesia team that is experienced in pediatric techniques (Chap. 5). If possible, mild hypotensive anesthesia will help to minimize blood loss. Preoperative nasal packing with neurosurgical cottonoids saturated with 1 ml of epinephrine 1:1000 solution (1 mg/cc or 0.1%) mixed with 1 ml of 0.05% oxymetazoline is also helpful in limiting blood loss in children. It is critical to alert the anesthesiologist that epinephrine is being applied into the nose and to monitor for tachycardia. No more than 1 ml of epinephrine 1:1000 should be used intranasally for packing in a bilateral case. In addition, if there are no medical contraindications, 1–2 mL of 0.25% bupivacaine or 0.5% Xylocaine with 1:200,000 epinephrine can be infiltrated in the medial canthal area prior to surgical prepping of the patient. This provides vasoconstriction, which also helps minimize operative blood loss. The simple application of two cotton tips (Q-tips) per surgical side dipped in epinephrine 1:1000 and pressed intranasally at the level of the middle turbinate should suffice.

Alternatively, the middle meatus on the appropriate side is packed with neurosurgical cottonoids saturated with 0.05% oxymetazoline. One may mix the oxymetazoline with an equal amount of 4% cocaine if this is acceptable to the anesthesiologist. Cocaine administered in this manner may produce toxic hypertensive or tachyarrhythmic side effects, and one should be familiar with appropriate dosing in young children [18].

After general anesthesia and injection of vasoconstricting agents, adequate time is allowed for them to exert their effect (approximately 5 minutes). During this time, the patient is prepped and draped in sterile manner for upper facial surgery. The location of the incision is somewhat variable in children, depending on the presence or absence of an epicanthal fold. If an epicanthal fold is present, the incision can be placed somewhat medial to the epicanthal fold if it is not to be repaired at the same time. More often the DCR can be performed through planned Y to V or Z-plasty incisions (see Chap. 21). Additionally, a certain number of patients will also have associated craniofacial anomalies, which will be operated upon at the same time. This situation may require a somewhat different external incision, for example, using a Y to V incision in the presence of telecanthus or altering the incision to excise a lacrimal anlage if present [19]. For the most part, however, a straight, vertical incision is usually preferred in the medial canthal area instead of a curved incision, which may tend to bowstring (Fig. 28.2).


Fig. 28.2
Incisions for external dacryocystorhinostomy. The dotted lines indicate the two incisions used in an external dacryocystorhinostomy in children: the lid crease and the medial canthal incisions. If epicanthal fold surgery is being performed at the same time, the DCR may be performed through Y-V or Mustarde Z-plasty flaps

Alternatively, a medial lower lid crease is also a useful site for an incision, which provides an excellent cosmetic outcome. After incising the skin, bleeding vessels are gently cauterized, and further dissection is carried out in a blunt fashion using a Freer elevator to dissect through the orbicularis muscle. Dissection is carried down to the periosteum of the anterior lacrimal crest. Lacrimal rakes (Storz, St. Louis, MO) are helpful in retracting the medial edge of the incision to allow blunt dissection to proceed posteriorly. Alternatively, a medium size muscle hook can be used for retraction. Depending on the location of the angular vessels, they are usually retracted out of the operative field either medially or laterally, depending on their relationship to the incision. If cut, they can be cauterized, although traction beneath the rakes is frequently sufficient for adequate hemostasis. After reflecting the orbicularis muscle off the anterior lacrimal crest, it is necessary to reflect the inferior portion of the anterior limb of the medial canthal tendon superiorly. The sharper end of the Freer elevator or scalpel is then used to incise the periosteum of the anterior lacrimal crest in a vertical fashion extending from the edge of the medial canthal tendon interiorly along the anterior lacrimal crest. The periosteum and lacrimal sac are then easily reflected laterally, revealing the shallow lacrimal sac fossa, which comprises the frontal process of the maxilla and the very thin lacrimal bone (Fig. 28.3).


Fig. 28.3
Incision of the periosteum on the anterior lacrimal crest. The periosteum on the anterior lacrimal crest is incised with either the sharper end of the Freer elevator or a #1.5 Bard-Parker scalpel blade. The periosteum is reflected revealing the lacrimal sac fossa

After the lacrimal sac is retracted laterally, the osteotomy can be initiated in a number of ways. In the very small child, a 2.3-mm-diameter-tip otodrill (Xomed-Treace, Jacksonville, FL) is useful in initiating the osteotomy without violating the nasal mucosa. In most young children, the lacrimal sac fossa can frequently be infractured through the thin lacrimal bone by using the blunt end of a hemostat (Fig. 28.4). In older children with thicker bone, an Arruga trephine that is 10 mm in diameter (Dixie, London, UK) can also be used to initiate the osteotomy (Fig. 28.5). There are two types of trephines: One has a sharp central point and coarser teeth to engage the bone and is used to create the initial cut. The other has finer teeth and can be gently worked down to the nasal mucosa and then rocked back and forth to remove a cylinder of the bone to expose the intact nasal mucosa beneath. The advantage of the trephine over other methods is the controlled exposure of the nasal mucosa as well as creating an adequate opening for the use of rongeurs.


Fig. 28.4
Infracturing. A hemostat can be used to infracture the thin nasal bone in posterior/inferior lacrimal sac fossa. After the infracturing, spreading of the hemostat may enlarge the initial osteotomy. Care is taken to avoid damaging the underlying nasal mucosa


Fig. 28.5
Arruga trephine . An Arruga trephine may also be used to initiate the osteotomy in older children

Ultimately, the easiest approach in all patients for external DCR is to outfracture the anterior ethmoid just posterior to the posterior lacrimal crest. A Rollet Rugine (John Weiss International, Milton Keynes, UK) can be used or a mosquito hemostat. This will allow enough space for a small-sized Kerrison rongeur to be used to create the initial rhinostomy. Care should be made to remove the bone from a posterior to anterior fashion, thus allowing better visualization and identification of the skull base.

The osteotomy is then enlarged to approximately 15 mm in diameter by removing most of the anterior lacrimal crest, the lacrimal sac fossa, and the posterior lacrimal crest with Kerrison rongeurs (Figs. 28.6 and 28.7) (Storz). A large osteotomy is important since there is a potential for closure with growth of the facial bones, and with a small rhinostomy, the lacrimal and mucosal flaps can more easily come into contact with the common canaliculus and cause scarring and a persistent lacrimal sac. It is important to place the osteotomy inferiorly so that should there ever be a need for a Pyrex tube bypass operation it could be adequately placed in the medial canthus. This involves the removal of the anterior portion of the nasal process of the maxilla at the juncture of the inferior orbital rim. In addition, if cotton tips are used, they should be retracted during the formation of the rhinostomy. The advantage of cotton tips (Q-tips) is that the wooden sticks can be readvanced to tent the nasal mucosa during the bony work to better identify the nasal mucosa and associated nasal space. Although care should also be taken to avoid tearing the nasal mucosa, this will sometimes occur. It is helpful to tilt the trephine so that the entrance into the nose occurs at the inferior edge. In this fashion the nasal mucosa can hinge superiorly when the flaps are cut. If the nasal mucosa remained intact throughout the creation of the osteotomy, it is injected with a small amount of 0.5% Xylocaine with 1:200,000 epinephrine to provide further vasoconstriction of the mucosal flap. It is frequently helpful at this point to pack the wound with neurosurgical cottonoids saturated with 1:200,000 epinephrine or liquid thrombin if there are no contraindications.


Fig. 28.6
Enlargement of ostium. The osteotomy is enlarged with neurosurgical microrongeurs


Fig. 28.7
Sagittal view of the DCR ostium (arrow). (A) Middle turbinate, (B) inferior turbinate, and (C) nasolacrimal duct

After allowing adequate time for vasoconstriction and hemostasis, the packing is removed, and a curved hemostat is used intranasally to tent the nasal mucosa outward (or the cotton tips can be advanced). Using a #11 blade, a large anterior mucosal flap is created (Fig. 28.8). This can also be made with the Colorado needle on a monopolar cautery unit. At this point, if there is any significant hemorrhage, a neurosurgical cottonoid or Gelfoam saturated with thrombin can be passed intranasally to tamponade the mucosa around the osteotomy. Because of rapid facial and bone growth, we favor silicone intubation in children to prevent closure of the osteotomy. At this point in the operation, a lacrimal probe (Storz) with attached silicone tube is passed through the lower canaliculus and used to tent the lacrimal sac outward. The #11 blade is used to create a vertical incision in the lacrimal sac from its fundus to the neck, creating both anterior and posterior mucosal flaps. An alternative is to use the Werb right-angle scissors to cut the junction of the nasolacrimal sac to the duct. One blade of the scissors is introduced into the sac, and the incision is carried superiorly to the fundus of the sac to create as large of an anterior flap as possible. At this point, a portion of the posterior lacrimal sac is excised for pathological examination. If the surgeon prefers, this posterior lacrimal flap can be anastomosed to the posterior nasal mucosal flap with a 5–0 or 6–0 Vicryl suture. The lacrimal probe with the attached silicone stent is then pulled out through the incision, and the other end of the tube with its attached probe is passed through the upper canaliculus into the lacrimal sac and brought out through the incision (Fig. 28.9). A silicone cuff that is packaged with the Guibor probe (Xorned-Treace, Jacksonville, FL) is cut to approximately 7–10 mm (depending on the size of the child’s intranasal anatomy) and passed over the probes and silicone stents (Fig. 28.10). The probes are then removed, and a hemostat is placed up the nose and used to pull the tubes through the osteotomy out through the nares. Multiple surgical knots are then tied so that the cuff is secured. The excess silicone stent is then cut off just inside the nostril and removed. It is not necessary to suture the ends of the tube in the nose, because they are easily visible in the middle meatus, even in a small child.


Fig. 28.8
Creating mucosal flaps . A vertical incision is made in the lacrimal sac to create anterior and posterior nasal mucosal flaps. Because of its angulation, a #66 Beaver blade is useful in this portion of the procedure. It can also be used to create a vertical incision in the nasal mucosa to create anterior and posterior mucosal flaps


Fig. 28.9
Silicone stents . Silicone stents are passed through the puncta, sac, and DCR osteotomy and brought out through the wound


Fig. 28.10
Fixation of the silicone stent . Each probe with tubing attached is passed through a length of larger bore silicone, which creates a noose effect for securing the loop of tubing. The loop should be loose enough to pull halfway to the corneal limbus without tension. The probes are then removed, and multiple knots are tied at the appropriate tension. The excess silicone ends are cut, and the knot and cuff are allowed to retract into the nose

An alternative to bicanalicular stenting is to use a monocanalicular stent (FCI ophthalmics) which has the advantage of being easier to remove and has been shown to be effective in DCR surgery (Fig. 28.11) [20].


Fig. 28.11
Use of the self-threading monocanalicular stent (Monoka, FCI Ophthalmics) in external DCR surgery. (a) A Ritleng probe is passed from the punctum through the common canaliculus. A Monoka stent can then be advanced into the Ritleng probe (see Chap. 27 for this technique). (b) Intranasal endoscopic view of a Monoka stent emanating from the common canaliculus after an external DCR

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Dec 19, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Management of Pediatric Lower System Problems: Dacryocystorhinostomy

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