The lacrimal system begins at the lacrimal punctum which starts at the myocutaneous junction of the medial aspect of the lid margin of upper and lower eyelids. The canaliculi extend from the punctum to the lacrimal sac. The canaliculus initially has a vertical path of 2 mm followed by a medial extension (8–10 mm) toward the lacrimal sac. As the canaliculi approach the lacrimal sac, they tend to combine to form the common canaliculus which enters the lateral wall of the lacrimal sac. The lacrimal sac lies within the bony depression of the anteromedial orbital wall, called the fossa of the lacrimal sac. In an average adult, the sac measures 12 mm in height, 4–6 mm in depth, and 2 mm in width. The nasolacrimal duct measures 3–4 mm in diameter and extends inferiorly. The nasolacrimal duct has two parts: the intraosseous part, about 12 mm in length, within the nasolacrimal canal of the maxilla, and the membranous or meatal part, which is 5 mm long and runs beneath the nasal mucosa before ending at the inferior meatus. The flap of mucosa at this exit is referred to as the valve of Hasner.

Patients with nasolacrimal injuries may present with significant concurrent facial wounds and multiple system injuries. It is essential to carefully check for any associated injuries such as neurological, thoracic, and abdominal trauma when significant facial trauma occurs. Such patients must be rapidly evaluated and stabilized first. The importance of meticulous history taking cannot be overemphasized. The physical examination should include an assessment of the soft tissues and bony involvement. Swelling, ecchymoses, and lacerations in periocular region are noted. Lacerations in the medial canthal region should be assessed to determine the integrity of the lacrimal drainage system and medial canthal tendon. A disruption of the medial canthal tendon can be assessed by a “traction test” [14, 15]. It is done by grasping the edge of the lower eyelid or upper eyelid laterally and pulling against the medial attachment. If the eyelid margin does not become taut and bowstring or you feel asymmetry in the two sides, then the medial portion of the tendon has likely been avulsed and disrupted. The other important structures in this area are the upper and lower canaliculi. Firstly, inspection of the lacrimal and canthal area should be done. A cotton tip can be used to gently palpate eyelid tissue. This can help define the location and extent of the injury. In addition, syringing and probing of the lacrimal system should be performed. Thorough lacrimal system evaluation including tear meniscus height, position and appearance of puncta and lids, regurgitation on pressure over lacrimal sac, irrigation of lacrimal system, fluorescein dye disappearance test, and whenever indicated diagnostic probing and nasal endoscopy should be carried out.

Inspection and physical examination of the patients with nasoethmoid–orbital injuries can help to predict the sites and extent of fractures prior to radiographical studies. The palpation over the bones onto the medial canthal tendon attachment may demonstrate bony crepitus or clicks depending on the degree of instability [16]. Bony fractures initiate an inflammatory and cicatrizing reaction that may result in NLDOs shortly or years after the injury [5]. Thorough clinical assessment of NLDO should be done 3–6 months after initial trauma or repair when resolution of edema and soft tissue injuries permit the definitive evaluation. The width and the symmetry of the medial canthi should be assessed for telecanthus. The normal inter-canthal width ranges from 30 to 35 mm in whites [14, 17, 18], or half of interpupillary distance [14, 19], which is a more reliable guide. The other obvious sign is saddle nose deformity which means loss of nasal skeletal support. Furthermore, typically, the medial aspect of the palpebral fissure may lose its sharpness and become rounded and slack with varying degrees of downward and outward displacement (Figs. 12.2 and 12.3). An ocular examination should be performed. Injuries in this area may be associated with ophthalmic emergency and problems such as ruptured globe or traumatic optic neuropathy especially when the principle fracture or displacement involves bones of the apex of the orbit [20–23]. A study by Holt et al. [24] found 59 % of nasal fractures showed concomitant eye injuries and 76 % of midfacial fractures were associated with eye injuries. Therefore, an initial ocular evaluation in midfacial fractures is necessary [25–27]. In conclusion, patients with nasoethmoid–orbital injuries are evaluated in three ways. The bony involvement, such as nasoethmoid fracture or nasolacrimal, naso-orbital fractures, or complex fractures, should be considered. The soft tissue injuries are especially concerned in medial canthal tendon area and lacrimal drainage system which includes canaliculi and lacrimal sac. The third part is appropriate ocular examination and visual assessment.

A facial CT scan is required in any patients suspected of having nasoethmoid injuries. Axial and coronal images with bone windows, spaced at 1.5–2 mm, are most effective in evaluating and classifying nasoethmoid–orbital fractures [28] (Fig. 12.4). Imaging of lacrimal system is often indicated in complex situations such as traumatic NLDO for proper assessment. Although DCG is considered the gold standard for imaging of the nasolacrimal system, it does not allow for imaging of the soft tissue or bony structures surrounding the nasolacrimal sac or duct [29]. Plain CT alone, however, is unable to diagnose securely a point of obstruction in the nasolacrimal duct. The CT-DCG gives useful information about complexity of anatomical change after trauma and repair, exact localization of the lacrimal sac, associated fractures, and bone displacements. It also provides information about the location of previously placed miniplates and screws, wire, or silastic sheets, which helps in preoperative planning and intraoperative decision-making [30–34] (Fig. 12.5).

Definitive treatment of nasolacrimal injuries should be deferred until the patient has been stabilized regarding any concomitant, compromising, or life-threatening or vision-threatening trauma. Ocular contraindications include optic nerve injury and globe injury (e.g., hyphema, rupture, laceration). These injuries should be addressed and stabilized prior to surgical intervention, since osseous manipulation may exacerbate damage to the eye. Some injuries may not need correction, provided that the patient is satisfied with the appearance and function.

Once definitive diagnosis of nasolacrimal injuries has been made, based on clinical evaluation and lacrimal imaging, the patient should be informed about their clinical condition, need for surgical intervention, types of surgery and anesthesia, and possible complications and success rate. Management for nasolacrimal injuries can be divided into two parts, bony fracture and soft tissue injuries which are divided into two subgroups, medial canthal tendon injuries, and lacrimal drainage system injuries which include canalicular lacerations.

Lacerations to the canaliculus and medial canthal injuries should be treated primarily, while injury to the lacrimal sac or nasolacrimal duct can be operated on later [35], because there is a chance of spontaneous improvement. Canalicular lacerations and medial canthal tendon injuries should be repaired within 72 h preferably to ensure the best possible outcome and to avoid scarring and epithelization of canalicular edges. Late repair is difficult, and patients often require conjunctivodacryocystorhinostomy (CDCR) to resolve their tearing problem.

Primary repair of maxillofacial and NOE injuries with open reduction and internal fixation of fractures should be performed early to provide optimal repair and minimize the incidence of late postoperative epiphora [7]. Lacrimal sac and nasolacrimal duct injuries should not be explored at the initial surgery if there is no obvious laceration. Studies showed spontaneous resolution of traumatic epiphora within 6 months after primary fracture repair [7, 13]. The incidence of late posttraumatic persistent epiphora due to NLDO requiring DCR ranges from 5 to 21 % [7, 11–13]. When DCR is necessary, it should be performed when the healing process is complete, which is 3–6 months after the primary repair.

Preexisting medical conditions need to be treated preoperatively to ensure that the patient is in the best possible health prior to surgery. General anesthesia is preferred in the setting of extensive nasoethmoidalorbital trauma, in more extensive injuries, and in pediatric population. There may be sclerosis and gross thickening of the bones after trauma, requiring drills or chisel–hammer to initiate the osteotomy [25]. Hence, it is preferable to operate cases of traumatic NLDO under general anesthesia whenever preoperative assessment predicts such intraoperative difficulty. Local anesthesia may be appropriate for adult patients with canalicular lacerations and medial canthal injuries and those with poor systemic health, particularly those with advanced cardiovascular or pulmonary disease.

The traditional method for repair of mono- or bicanalicular lacerations involves repair of the eyelid defect after placement of a bicanalicular stent. The introduction of Mini Monoka© stents has allowed repair of simple monocanalicular lacerations under local anesthesia, avoiding intranasal manipulation and sedation.

The most difficult part of canalicular repair is locating the medial end of the severed canaliculus. Therefore, canalicular lacerations should be repaired within 24–48 h after injuries because the medial cut edge of canaliculus becomes progressively more difficult to identify as fibrin and granulation deposition occurs (Fig. 12.6). The medial cut edge of canaliculus is identified successfully by direct inspection. The cut canaliculus is identified as white mucosal tissue with wall and lumens. Careful inspection with gentle traction of the crowded tissue with cotton tips is often necessary. If discovery of the lumen remains difficult, injection of air into the uncut canaliculus while observing the medial cut area submerged in saline may uncover its location with the appearance of air bubbles [36, 37].

Bicanalicular intubation is considered to be the gold standard for mono- or bicanalicular lacerations. This tube creates a “closed-loop” system that is unlikely to become dislodged. Placement of such tubes, however, does require intranasal packing with lidocaine and epinephrine; intravenous sedation or general anesthesia may be required.

Monocanalicular stent allows for placement under local anesthesia alone; however, these stents are less secure compared with the bicanalicular type and can be dislodged in children quite easily. Punctal injury precludes the use of a monocanalicular stent. The various types of stents are briefly described in Table 12.1.