Fig. 32.1
Dacryoendoscope with rigid telescope and black eye piece
Fig. 32.2
A closer view of side port
Canalicular obstructions and NLDO are therapeutic challenges. Most of the lacrimal obstructions are known to follow the common final pathway of inflammation and fibrosis, even if there is a wide range of etiological factors. Canalicular obstructions can occur following infections, inflammations like Stevens-Johnson’s and lichen planus, posttraumatic and post-topical ocular medications and systemic chemotherapy [11–13]. Numerous modalities with variable success rates have been described for canalicular obstructions and include retrograde intubation dacryocystorhinostomy, membranectomy, endocanalicular laser surgery, canalicular trephination, and balloon canaliculoplasty [14–18]. For nasolacrimal duct obstructions (mostly partial), alternative options to a DCR described include therapeutic trephination and intubation, silicone intubation alone and anterograde balloon dacryoplasty, electrocauterization or diathermy-assisted recanalization of NLDO (RC-NLDO), radiofrequency recanalization, and microsurgical NLD rhinostomy with eversion technique [19–26].
Instruments and Techniques
1.
Dacryoendoscope
2.
1-ml syringe with saline
3.
Camera head
4.
Endoscopic viewing system
5.
Antifog solutions (ex-diluted chlorhexidine)
6.
Sisler’s trephines
7.
Huco trephines
8.
Additional instruments based on the technique like Microdrill or laser or balloon dacryoplasty
The dacryoendoscope has a thin, rigid fiber endoscope and a side port on the hand piece (Figs. 32.1 and 32.2). The rigid fiber endoscope is attached to the eyepiece through a fiber-optic cable (Fig. 32.1). The eyepiece of the dacryoendoscope is connected to the camera head and secured. The camera head is then connected to the endoscopic viewing system (Fig. 32.3), and the tip of the scope is gently cleaned with antifog solution and image quality is assessed.
Fig. 32.3
Endoscopic viewing system
The dacryoendoscopy can be performed in an anterograde or a retrograde manner. For the recanalizations procedures, the anterograde approach is used. It is important to know that illumination may need to vary in different parts of the lacrimal system, especially when there are obstructions.
Indications
The indications for the recanalizations procedures are as follows:
1.
Complete canalicular obstructions
2.
Complete nasolacrimal duct (NLD) obstructions
3.
Symptomatic partial obstructions.
4.
Patchy or multifocal canalicular or NLD strictures
5.
Obstructive dacryolithiasis
6.
Obstructive foreign bodies, for example, migrated punctal plugs
7.
Membranous canalicular obstructions following a DCR
Contraindications
1.
Acute canaliculitis
2.
Acute dacryocystitis
3.
Posttraumatic obstructions following gross fractures
4.
Misaligned canaliculi
5.
Acute infective rhinitis (for nasolacrimal recanalizations)
Techniques
1.
Dacryoendoscopic guided canalicular and NLD trephination
2.
Laser dacryoplasty
3.
Microdrill canaliculoplasty
4.
Balloon canaliculoplasty
5.
Diathermy-based recanalizations
Canalicular Recanalization Techniques
Canalicular trephination can be carried out using laser, microdrills, or balloons under dacryoendoscopic visualization or, alternatively, using trephines under similar guidance. Sisler’s trephines were described in the year 1990 as specialized microtrephines designed for the canaliculi [14]. The trephine is 16 mm in length and 0.81 mm wide with a plastic hub behind for a syringe or simply to hold during the boring movements. It is accompanied by an intraluminal stylet or guide (Fig. 32.4). Dacyroendoscope is used to assess the type of obstruction (partial or complete), its distance, and its appearance. It is important to differentiate stenosis from various degrees of obstructions (Figs. 32.5, 32.6, 32.7, and 32.8). Lubricated trephine is inserted to the point of obstruction with its accompanying stylet in place to minimize trauma to the proximal, patent canaliculus. The syringe is then affixed to the trephine’s luer-lock hub and trephination is carried out by gentle rotation of the assembly. After each millimeter boring, dacryoendoscope is used to assess the extent of clearance, assess further passage, and obstruction. Bleeding is usual since the obstruction is a fibrovascular tissue and it should be simultaneously cleared by irrigating the canaliculus with saline from the side port. The trephination is continued and when the sac is entered, the syringe will pop indicating achievement of the desired passage and a plug of scar tissue is seen either within the lumen of trephine or barrel of the syringe (Fig. 32.9). Dacryoendoscope is inserted to ascertain completer recanalization (Fig. 32.10). This is followed by stenting of the new passage with mono- or bicanalicular stents. Postoperatively, a combination of topical antibiotic and steroid is continued in a tapering fashion for 4 weeks. The author retains the tubes for 3 months in recanalizations cases.
Fig. 32.4
Sisler’s canalicular trephine with intraluminal stylet
Fig. 32.5
Canalicular stenosis
Fig. 32.6
Partial canalicular obstruction
Fig. 32.7
Complete canalicular obstruction
Fig. 32.8
Complete canalicular obstruction
Fig. 32.9
Obstructed sculpted segment in trephine barrel
Fig. 32.10
Complete canalicular recanalization
Laser dacryoplasty is performed using Erbium:YAG laser or KTP:YAG laser [8, 17]. For this purpose the dacryoendoscope needs to have an additional channel for the passage of laser fiber. Laser delivery using a sapphire fiber of 375 μm, and energy of 50 mJ with 1–3 Hz frequencies have been described. The procedure is the same as described earlier but instead of a mechanical trephine, laser is used to lyse the fibrous tissues, followed by irrigation and intubation [8, 17].
Microdrill dacryoplasty was introduced by Busse [6]. The additional channel on dacryoendoscope is designed to carry a battery-operated 0.3-mm stainless steel microdrill shaft. The frequency to begin was 50 Hz but now powerful drills up to 3,000 Hz are available. The microdrill is best suited for partial obstructions, where the drill starts from the edge of the patent lumen to recanalize it further. It is very important to have a continuous irrigation and suction with a clear visualization and utmost control on the instruments, since the possibility of canalicular lacerations can be high if the shaft is not accurately positioned [6].
Balloon canaliculoplasty is sparsely reported in the literature [16]. It uses a 2-mm balloon for recanalizations following probing just like in balloon dacryoplasty. The inflation–deflation cycles at 8 atm of pressure is followed by intubation. It was found to be more effective in common canalicular obstruction as compared to isolated canalicular obstructions.
Nasolacrimal Duct Recanalizations Techniques
Nasolacrimal duct obstructions are an enigma. Recanalization approaches used include dacryoendoscopic guided Huco trephination and intubation, anterograde balloon dacryoplasty, electricity-assisted recanalization of NLDO (RC-NLDO), and Javate’s mechanical recanalizations under simultaneous guidance [19–25]. Trephination is usually done using the Huco trephine (Fig. 32.11). Lubricated trephine is inserted to the point of obstruction with its accompanying stylet in place to minimize trauma to the proximal, structures. The trephination is carried out by gentle rotation of the assembly. After each millimeter boring, dacryoendoscope is used to assess the extent of clearance, assess further passage and obstruction, modify the course, and confirm complete recanalizations (Figs. 32.12, 32.13, 32.14, and 32.15). Bleeding is usual since the obstruction is a fibrovascular tissue and this needs to be cleared simultaneously with saline irrigation of the NLD from the irrigation port (Fig. 32.2). Crawford silicone intubation was performed and retrieved through the NLD and secured in the inferior meatus (Fig. 32.16), following the recanalization procedure.
