Fig. 20.1
The transconjunctival incision
Fig. 20.2
Dissection to access the anterior lacrimal crest
Fig. 20.3
Bony osteotomy
Nasal and saccal mucosae are incised to “H”-shaped flaps, as in external DCR. Full-thickness sac incision and common canalicular patency are checked. The contents of the sac are emptied by irrigation. The nasal and saccal posterior mucosal flaps are best anastomosed with 6–7/0 polyglactin sutures, preferably on a 5/8 curved round needle. When posterior flap apposition is impossible because of either poor manipulation in a deep surgery site or lacerated flaps, it is advised to excise the remnants of posterior flaps. Bicanalicular silicone intubation can be done prior to the anastomosis of the anterior nasal and saccal flaps (Fig. 20.4). Periosteum is closed in a fashion to suspend the anterior mucosal wall of the anastomosis. The medial conjunctiva is approximated and sutured with 6-0 polyglactin or may be left unsutured if well apposed (Fig. 20.5).
Fig. 20.4
Probe tip in the sac before suturing anterior flaps
Fig. 20.5
Incision site at the end of surgery
The surgeon may choose to convert the surgery to conventional external DCR with skin approach, whenever an adequate size bony ostium could not be created to expose the nasal mucosa to complete the DCR via transconjunctival route. Agger nasi cell may prevent access to the nasal cavity, and other posterior ethmoidal cells may be entered instead.
Postoperative Care
Eye patching for 4 h with sterile antibiotic and corticosteroid ointment after surgery is safe and comfortable for the patient. The eyes are opened early on surgery day to check for hemorrhage. It is advised to keep the patient in supine position and apply ice compresses in the first 24 h. Topical and systemic antibiotics are prescribed for the 1st week, and nasal and ocular steroids and nasal saline spray are continued for 3 weeks after surgery. Patients are also advised not to blow the nose during the 1st week.
Figures 20.6, 20.7, and 20.8 show the typical postoperative course of a patient who had transconjunctival DCR for treatment of PANDO. We suggest to follow up the patients on the 1st day, after 1 week, and 1, 3, and 6 months afterwards. During the follow-up, the incision site is examined and the patency of the new rhinostomy is assessed by a dye test or irrigation if required. Silicone tubes are mostly removed at 4 weeks.
Fig. 20.6
Postoperative view: 1st day
Fig. 20.7
Postoperative view: 2nd week
Fig. 20.8
Postoperative view of incision site: 2nd week
Outcomes
The success rate of transconjunctival DCR is over 90 % which is comparable to the success of external DCR [27]. It is easy to convert the surgery to external DCR when needed. In the author’s series of 25 patients, 76 % of the eyes could be successfully operated using TC-DCR and among these, epiphora resolved completely in 94.7 % eyes [27]. In the remaining 24 %, the DCRs needed to be completed via with cutaneous approach because of fat prolapse hindering adequate osteotomy. Ethmoidal cells were entered in 12.5 % of the eyes. Although Becker reported 92.5 % success in patients who underwent external DCRs without flaps [7], general surgical principles advocate the endothelium-lined smooth tract for the long-term patency of the anastomosis and the drainage of tears. High success rate of transconjunctival DCR can be attributed to the successful flap anastomosis.
Table 20.1 summarizes the advantages of TC-DCR. Surgical difficulties and disadvantages of TC-DCR are listed in Table 20.2.
Table 20.1
Advantages of TC-DCR
1. Avoids facial scar |
2. Minimal trauma to medial canthal structures |
3. Preserved lacrimal pump |
4. Enables flap anastomosis |
5. Surgery with basic DCR equipment |
6. No need for endoscopy and laser assistance |
Table 20.2
Difficulties and disadvantages of TC-DCR
1. Difficult visualization of deeper planes |
2. Difficult access to the sac and lacrimal fossa |
3. Tight lower eyelids are prone to injury |
4. Manipulation and maneuvering difficulties (Ethmoid cell entry, agger nasi cell, orbital fat prolapse) |
5. Longer procedure time |
6. Variable learning curve |
Disadvantages
The higher rate of conversion to external DCR (24 %) especially during the learning curve appears to be the major disadvantage of TC-DCR technique. [27] It is occasionally difficult to reach the nasal mucosa and suture the flaps in the deep surgical planes. In our series of the first 25 cases of transconjunctival DCR, incidence of converting to cutaneous approach external DCR to complete surgery (technical failure) decreased from 38.5 % (first 13 eyes) to 8 % (last 12 eyes) in the second half of the patient group [27]. This result may point towards a learning curve, but the decrease in this conversion as we gain experience is noticeable.
Complications
Orbital fat prolapsed was commonly encountered while performing transconjunctival DCR, which is considered to be one of the important reasons for DCR failure according to Welham et al. [28]. In presence of this complication, manipulation of bony and soft tissues is difficult, and undue trauma to the fat tissue may end up with retroseptal hemorrhage. Fat prolapse, whenever encountered, should be retracted from the site, and the periosteum should be closed meticulously after rhinostomy and flap suturing to prevent fat tissue incarceration in the rhinostomy site.
Anteriorly located ethmoidal air cells can occasionally confuse the surgeon. Talks and Hopkinson reported that the ostium was opened via the standard lacrimal fissure in only 46 % of DCRs [29]. Ethmoidal cells beyond the agger nasi might occasionally be violated. Occasionally the ethmoidal sinus entrance might be a hindrance in fashioning the appropriate rhinostomy site in transconjunctival DCR, although it does not mandate conversion to an external DCR.
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