Lacrimal System Trauma to the Eye
Lacrimal System Trauma to the Eye
I’m Ed Smith, a Sacramento Eye Injury Lawyer. Lacrimal system trauma to the eye frequently occur along with eyelid and facial trauma. Canalicular lacerations in particular may be subtle and therefore must be suspected so that a careful repair can be carried out. Injuries to the lacrimal system can occur with blunt or sharp lacerations. Falls, car accidents, and blows with blunt objects may cause shearing forces or tearing forces to the lid, causing an avulsion of the medial canthus. The lid tends to tear at its weakest point, which is at the attachment of the medial canthal tendon to the tarsus, lying hear the inner corner of the eye (the punctum). Occasionally, the tear can be medial to that and can lacerate the tear duct, which is more difficult to identify and to repair.
Lacerations to the Eye
Sharp lacerations such as those seen in a stab wound or from shards of glass or metal in a car accident can occur at any portion of the canalicular system or in the area of the lacrimal sac (where tears are produced). Concurrent injuries to both canaliculi are more common with sharp injuries. Dog bites are major sources of eyelid and canalicular lacerations, especially in children, providing components of both sharp and avulsive injuries. Because the lacrimal sac is somewhat protected, it is less commonly involved in such trauma but can be disrupted if there are nasolacrimal fractures.
In examining the patient with damage to the lacrimal system, it is important to take a complete history to determine the likelihood of retained foreign bodies like gravel or tree branches. A search must be made for foreign bodies both before and during surgery for unsuspected foreign bodies. This can be done with an operating microscope or a slit lamp examination.
X-Rays and MRIs
In some settings, careful nasal examination with a speculum, using appropriate decongestion of the nasal mucosa and a good light source can be helpful in identifying nasal trauma and avoiding problems with subsequent repair of the nasolacrimal system. Facial fractures must be considered and x-rays obtained to rule this out. CT scan is especially helpful in evaluating orbital fractures and nasoethmoidal fractures
Usually, general anesthesia is preferred in examining the eye in this type of setting, especially in children and in adults who do not have simple eyelid injuries. Sometimes the nasolacrimal system needs to be intubated under local anesthesia by numbing the nose, the lacrimal sac, and the nasolacrimal duct. This can be quite time consuming, making general anesthesia more appropriate.
Instruments used to repair Lacrimal System Trauma to the Eye
Special instruments must be used to repair the lacrimal system, including punctum dilators, canalicular probes, and intubation materials. There is general agreement that silastic tubing is the best material for intubating the nasolacrimal duct because it is soft and readily placed, and produces no tissue reactivity. Polyethylene tubing can be used but it is stiff and tends to erode into the punctum and lacrimal system. Intubation sets are commercially available in prepackaged sterile units that make use of stainless steel wires swaged onto the silastic tubing.
One drawback of silastic intubation sets is that they necessitate manipulating and intubating the uninjured canaliculus in the case of a single canalicular laceration. A regular silastic intubation set can be used by looping the tubing externally between the exterior part of the nose and the medial canthus. This may be difficult to do in a child.
Suture material of a large caliber including nylon, Mersilene, polypropylene and others have been used to intubated the nasolacrimal system. They may be helpful in some situations, however, silastic is considered the preferred material for repair.
Surgical repair of the eyelid and the nasolacrimal system has two phases: 1) intubation of the canaliculus and lacrimal system as necessary, and 2) repair of the lid laceration. The surgery must be done carefully after examining the wound and looking for foreign bodies while copiously irrigating the wound in order to remove contaminants.
In intubating the lacrimal system, an intact punctum may need to be dilated to allow passage of the lacrimal probes. Tight puncta may need to be snipped in order to allow for intubation of the lacrimal system. The probe is passed through the punctum and out through the wound in the eyelid unless the canaliculus is only partially severed, in which case it may be passed directly to the medial cut edge of the canaliculus and then to the lacrimal sac. Identification of the medial cut end of the lacrimal sac is then done under good magnification and lighting, with help from irrigation.
When intubating the nasolacrimal duct, the probe is passed from the inner aspect of the eye at the punctum, through the nasolacrimal duct and out of the nostril on the affected side. This allows the nasolacrimal duct to heal with the entirety of the duct to remain open during healing.
Surgical repair of the lid follows standard plastic surgery techniques. If there has been any loss of the eyelid as part of the trauma, it may be necessary to relax the lid by doing a lateral cantholysis. There should be careful suturing of the margin of the lid for cosmetic reasons and the sutures should be tied anteriorly in order to prevent a corneal abrasion. Canalicular lacerations usually heal quite well if there is no tension on the wound.
Lacerations caused by avulsion of the eyelid deep in the medial canthus are hard to repair because of the small space in which to work. It is often not possible to suture the canaliculus directly. Therefore, there must be careful approximation of the tissues in order to prevent rotation of the canaliculus and to avid the likelihood of scar tissue formation, which might distort the repair after it heals.
Lacrimal sac injuries are relatively unusual except in cases of nasoethmoidal fractures and severe penetrating injuries to the medial canthal area. Identification of the lacrimal sac may be difficult but If it can be primarily repaired, it is reasonable to do so. Silastic intubation should be performed as a primary procedure if possible.
A number of complications can occur as a result of repair of the canalicular and lacrimal drainage system. Several may be due to poor surgical technique but others occur because the injury is so severe that even the most meticulous repair is doomed to failure. The primary complication is an inability to obtain anatomic and physiological patency of the system. This can be caused by failure to use a stent or to early removal of the stent, scarring from the initial injury, or distortion by improper apposition of the canaliculus and surrounding lid structures.
Punctal erosion can come from pressure from tight silastic tubing. This can be avoided by careful fixation of the silastic tubes in the nose, by the moncanalicular intubation, or by the use of loops of silastic material through the canalicular system rather than down into the nasolacrimal duct.
Displacement of the silastic tubing can be troublesome. Suture fixation of the tubes in the nose can help prevent this displacement. Occasionally, the sutures erode, leaving the tubes free. A slight displacement can often be corrected by pushing the tubing back into the sac, having the patient forcefully blow his nose, or by manually repositioning them.
Lid notches occasionally occur, particularly if there is loss of tissue or extensive distortion of the tissue that might make identification of the structures difficult. Careful approximation of the lid margin, paying close attention to all landmarks will generally prevent notching. Lacrimal pump problems from distortion of the lateral portions of the lid may result from widespread injury in the periorbital area but can be prevented by good surgical technique. If you have suffered lacrimal system trauma to the eye call an experienced Sacramento eye injury lawyer.
Eye Injury Lawyer Serving Sacramento
I’m Ed Smith, a Sacramento Eye Injury Attorney since 1982. Our website, www.AutoAccident.com is the leading personal injury website in California. Call me anytime at 916-921-6400 or 800-404-5400 for free, friendly advice.
Member of Million Dollar Advocates Forum.