Penetrating orbital injuries require a careful evaluation of the eyelids and the underlying soft tissues. The extent of the penetrating injury and the presence of foreign bodies are vital determinations in the initial management. Sharp objects such as broken glass or knives are common causes of significant lid lacerations. Dog bites are also a common cause of lid lacerations, especially in children, and they have a propensity to involve the canalicular system. In a retrospective analysis of eyelid lacerations over the course of a decade, Savar et al. [2] found that 66% of patients who suffered dog bite injuries had resultant canalicular damage. The majority of these injuries involved damage to the inferior canaliculus [2]. Thus, a careful history detailing the timing and mechanism of injury in addition to a physical exam that rules out injury to the globe and assesses for changes in vision and diplopia are required. CT imaging without contrast can help to delineate the magnitude of any orbital injury.

During the initial patient encounter, tetanus status and inoculation history should be obtained. All patients should receive broad spectrum of antibiotics and pain management prior to wound exploration [3]. Soft tissue lacerations should be evaluated carefully to determine the extent of the damage. Eyelid lacerations can often be repaired at the bedside if the canalicular system is not involved. Canalicular injury can be presumed if the penetrating injury on the eyelid margin is full thickness and medial to the punctum [4, 5]. These patients can also present with displacement of the punctum laterally [5]. Lacerations can be the result of direct penetrating trauma or lid avulsion in the setting of tension forces inflicted on the eyelid. Avulsion injuries are more difficult to repair as shearing forces tend to impair easy visualization of the lacerated tissues [4]. Lacrimal system probing is required to confirm the diagnosis of a canalicular laceration. If lacrimal system injuries are not repaired, occlusion of the canalicular system will likely ensue, and a fistula tract may arise, as a result of scar formation. This may result in tearing, as each canaliculus provides approximately 50% of the tear drainage [4].

In the setting of lid avulsion, the medial canthal tendon will need to be reattached to its original anatomic insertion if disinserted (Fig. 7.2). The medial canthal tendon attaches anteriorly to the anterior lacrimal crest (the frontal process of the maxilla) and posteriorly to the posterior lacrimal crest (within the lacrimal bone). The canthal tendon hugs the lacrimal sac as it courses to its bony attachment. Proper apposition of the eyelid to the globe requires attachment of the posterior portion of the medial canthal tendon, and normal anatomic rounding of the lower lid requires attachment of the tendon to the anterior lacrimal crest. This alignment also helps to ensure proper positioning of the puncta in the tear lake.

Canalicular injuries are not always evident on cursory gross inspection, and it is prudent to evaluate all lid lacerations for canalicular involvement, after the globe is evaluated and it has been deemed safe to evaluate the lids and lacrimal system. Epidemiological reports have indicated that canalicular injuries are more common in young, male patients. One study revealed that almost 70% of canalicular lacerations were found in patients younger than 30 years old [6], and another study found that among young patients who suffered canalicular lacerations, 83% were male [7]. In order to diagnose canalicular trauma, punctal probing should be performed. A drop of topical anesthetic is instilled and a punctal dilator can be used initially to allow easier entry into the punctum if stenotic. Once a lacrimal probe is introduced into the punctum, the clinician should follow the anatomical path of the proximal lacrimal apparatus. The probe should be inserted perpendicular to the eyelid margin entering the punctum for approximately 2 mm, then turned at a sharp 90 degree angle to be parallel to the lid margin. At this point the probe can be advanced up to 8 mm through the canaliculus. If at any point the metal end of the probe can be visualized, a canalicular laceration is confirmed (Fig. 7.2). Lacrimal irrigation can also be used to confirm a canalicular laceration. After instilling topical anesthesia, a blunt lacrimal irrigation cannula attached to a 1 or 3 mL syringe, filled with normal saline, is inserted into the lacrimal apparatus entering the punctum and proximal canaliculus. Saline is injected slowly, and in a patient with an intact lacrimal system, saline will pass into the nasopharynx and the patient will feel and taste the fluid. In the setting of a canalicular laceration, the injected saline will exit in the area of the canalicular laceration and can be visualized. If punctal probing or lacrimal irrigation is not available, careful examination with magnification using a slit lamp or surgical magnifiers (surgical loupes) can be used to help identify canalicular lacerations (Fig. 7.3).