Injury to the lacrimal canaliculus leads to scarring and stenosis, which in turn cause complete or incomplete obstruction of the canaliculus, and such patients present with epiphora. There is general agreement on the need for urgent primary microsurgical repair with silicone intubation,1 and the tube should remain in place for 3 to 6 months to prevent anastomotic stenosis. Even so, 6 to 15 percent of patients with canalicular laceration suffer from epiphora after silicone tube intubation.2 A combination of upper and lower canalicular injury, use of a pigtail probe, and failure to use silicone intubation are possible important factors that lead to postoperative canalicular obstruction.3 However, there is still no consensus on the causes of postoperative epiphora.
The soft tissues along the canaliculus are not consistent. With increasing distance from the lacrimal punctum, more soft tissue surrounds the canaliculus.4 The first 4 mm of the canaliculus lies between the conjunctiva and the tarsal plate; subsequently, it travels deeper and enters the orbicularis muscle and passes under the medial canthal ligament into the lacrimal sac. Finally, the last 2 to 3 mm is deeper and is surrounded by the fibers of the lacrimal sac fascia. We can assume that the site of canalicular injury may be an important factor that predisposes the patient to postoperative canalicular obstruction and epiphora. We presume that sites close to the sac will have a higher incidence of scarring and stenosis and be more likely to induce postoperative obstruction.
Forty-five patients with canalicular lacerations underwent urgent reparative surgery; bicanalicular silicone tube intubation was performed and the tube was retained for 3 months. The patients were divided into three groups on the basis of measurement of the distance from the punctum to the distal cut end of the canaliculus (i.e., distance): group A (distance, ≤4 mm), group B (5 mm ≤ distance ≤ 7 mm), and group C (distance, ≥8 mm). After 6 months, irrigation of the lacrimal passages was performed to evaluate the outcome. The incidence of postoperative obstruction in each group was analyzed statistically and compared by a cross-tabulation chi-square test (Table 1).
Group A consisted of 15 patients, group B consisted of 21 patients, and group C consisted of nine patients. After 6 months, a total of four patients (8.9 percent) appeared to have obstruction, as evaluated by irrigation of the lacrimal passages: three in group A (20 percent), one in group B (5 percent), and none in group C. The incidence of postoperative canalicular obstruction was not significantly different (p = 0.074) between groups A and B (Fig. 1).
In contrast to the expected outcome, based on the anatomical characteristics of the canaliculus, the lowest incidence of postoperative canalicular obstruction was in group C; group A showed the highest incidence. We suspect that the presence of tissue surrounding the canaliculus was the reason for the high incidence of postoperative canalicular obstruction in group A. Serial histologic sections of a fetus at 14 to 16 weeks of gestation revealed that the extent of the envelope formed by the Horner muscle around the canaliculus decreases gradually from the lacrimal punctum to the lacrimal sac.5 However, further research is needed to prove this theory.
WoDong Shi, M.D., Ph.D.
Xianqun Fan, M.D., Ph.D.
Department of Ophthalmology, Shanghai Ninth People's Hospital, Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
The patient provided written consent for the use of his images.
The authors have no financial interest in the methodology described in this article. There was no source of funds for this work.
This work was sponsored by the Shanghai Leading Academic Discipline Project (S30205), the National Natural Science Foundation of China (30973279), and the Cooperative Foundation of Medical and Engineering Science of Shanghai Jiaotong University (project no. 40YG2009ZD102).
1. Spinelli HM, Shapiro MD, Wei LL, Elahi E, Hirmand H. The role of lacrimal intubation in the management of facial trauma and tumor resection. Plast Reconstr Surg. 2005;115:1871–1876.
2. Kersten RC, Kulwin DR. “One-stitch” canalicular repair: A simplified approach for repair of canalicular laceration. Ophthalmology 1996;103:785–789.
3. Kennedy RH, May J, Dailey J, Flanagan JC. Canalicular laceration: An 11-year epidemiologic and clinical study. Ophthal Plast Reconstr Surg. 1990;6:46–53.
4. Kakizaki H, Zako M, Miyaishi O, Nakano T, Asamoto K, Iwaki M. Overview of the lacrimal canaliculus in microscopic cross-section. Orbit 2007;26:237–239.
5. Shinohara H, Kominami R, Yasutaka S, Taniguchi Y. The anatomy of the lacrimal portion of the orbicularis oculi muscle (tensor tarsi or Horner's muscle). Okajimas Folia Anat Jpn. 2001;77:225–232.
Viewpoints, pertaining to issues of general interest, are welcome, even if they are not related to items previously published. Viewpoints may present unique techniques, brief technology updates, technical notes, and so on. Viewpoints will be published on a space-available basis because they are typically less timesensitive than Letters and other types of articles. Please note the following criteria:
- Text—maximum of 500 words (not including references)
- References—maximum of five
- Authors—no more than five
- Figures/Tables—no more than two figures and/or one table
Authors will be listed in the order in which they appear in the submission. Viewpoints should be submitted electronically via PRS' enkwell, at www.editorialmanager.com/prs/. We strongly encourage authors to submit figures in color.
We reserve the right to edit Viewpoints to meet requirements of space and format. Any financial interests relevant to the content must be disclosed. Submission of a Viewpoint constitutes permission for the American Society of Plastic Surgeons and its licensees and assignees to publish it in the Journal and in any other form or medium.
The views, opinions, and conclusions expressed in the Viewpoints represent the personal opinions of the individual writers and not those of the publisher, the Editorial Board, or the sponsors of the Journal. Any stated views, opinions, and conclusions do not reflect the policy of any of the sponsoring organizations or of the institutions with which the writer is affiliated, and the publisher, the Editorial Board, and the sponsoring organizations assume no responsibility for the content of such correspondence.