Health

Lateral canthotomy: How to do it? [Everything Explained]

lateral canthotomy

Being able to carry out lateral canthotomy and cantholysis is a vital ability for any ophthalmologist or emergency room doctor.

It could be a valuable way to improve vision in cases of reduced perfusion of the optic nerve the globe because of an increase in pressure in orbit. Additionally, it can be a practical step in many procedures for the eyelid that are common.

Orbital compartment syndrome (1) can be an ophthalmic issue resulting in rapid blindness if not treated and diagnosed.

Canthotomy and lateral canthotomy is the preferred treatment and involve removing surgically the lateral canthal tendon and its inferior crus to ease the pressure inside the orbit.

This guide will provide methods, indications, and techniques used to perform lateral canthotomy and cantholysis.

Indications

Orbital compartment syndrome

The orbit is comprised of four bony bones within the skull that angle posteriorly and form a cone.

  • The roof is made up of the frontal and lower sphenoid bone’s wing.
  • The medial wall consists of the ethmoid, the lacrimal maxillary, sphenoid and ethmoid bones.
  • The floor is comprised of the palatine, maxillary, and zygomatic bones.
  • The lateral wall consists of the zygomatic as well as the greater sphenoid’s wing.
  • The globe and its orbital rim are the primary boundaries of orbit.

It is an enclosed chamber, and any process that expands within the orbit can create pressure on surrounding structures.

One example of this is the occurrence of retrobulbar hemorrhage. The increased pressure on the orbit can lead to the motion of the globe’s anterior part, which is characterized clinically as proptosis.

The forward displacement of the world is restricted by the eyelid structure held to the rim of the orbit, primarily by the medial and lateral canthal tendon.

In rare instances, orbital pressure may rise over the force of perfusion to the optic nerve, leading to inflammation of the retina and optic nerve. It is a severe eye-threatening problem and must be treated immediately.

Pressure in the intraorbital area can be measured indirectly by the measurement of intraocular pressure.

The clinical signs that indicate decreased perfusion due to orbital compartment syndrome comprise:

  • diminished visual acuity
  • intraocular pressure that is greater than 35-40mmHg
  • Afferent pupillary defects that are relative or
  • Reduced arterial circulation of the optic nerve as seen in the absence of pulsing or flow of retinal vessels with minimal or zero digital pressure across the globe.

The release of the lateral canthal tendon off the orbital edge doing a lateral canthotomy and cantholysis allows for a more remarkable anterior shift of the globe. It leads to a decrease in pressure intraorbital and an improvement in the retinal circulation and optic nerve.

Eyelid surgery procedures

A lot of common eyelid surgeries that are not emergency-related may also require cantholysis and lateral canthotomy.

The most effective illustration is the lateral strip. In this instance, the lateral canthal tendon gets removed, and a new, less pronounced “lateral canthal tendon” is formed by securing the tendon to the periosteum of the orbital rim.

It can effectively tighten the lower lid and may be an effective remedy for entropion and ectropion triggered by the increased laxity of the top.

The lateral canthotomy and the cantholysis may also be used for procedures that enhance lower lid laxity to fill in all-thickness lower lid imperfections.

Supplies

There are a lot of items readily accessible for routine eyelid procedures. This list is designed to serve as an inventory of the supplies required in the event of an emerging lateral canthotomy as well as cantholysis.

  • Topical proparacaine topical
  • Local anesthetic (lidocaine 2% ) with an epinephrine 1:100,000. Syringe, 20 gauge needle to draw out anesthetic and a needle of 27 gauge to inject)
  • The surgical drape
  • Antiseptic topical (ex. Povidine-iodine)
  • Surgery loupes
  • Sterile gauze
  • The utility scissors, Stevens or Westcott scissors
  • Iris scissors, if they are available.

Indications for Lateral Canthotomy

  • Ocular compartment syndrome (OCS) is an ophthalmologic condition that manifests as rapid, progressive loss of vision and increases intraocular pressure. diminished extraocular mobility and pain in patients who have suffered a recent injury to the eye or orbital area or surgery

A blunt facial injury (see Eye Contusions and Lacerations) can result in retrobulbar hematomas or severe edema around the eyeball, both of which may elevate the pressure in orbit.

Because the lids strain the eye and the trajectory, increased intraorbital pressure could cause intraocular tensions to rise quickly and compress the optic nerve and its blood supply. If left untreated, this pressure rise can cause permanent loss of vision (OCS).

Lateral canthotomy and Cantholysis are performed immediately to alleviate intraorbital pressure while preserving vision in the event of signs of OCS.

Contraindications to Lateral Canthotomy

Absolute contraindications

  • Susceptible globe rupture (e.g., an irregular pupil or hyphema, herniated iris tissue cornea leak of the aqueous humor)

Complications of Lateral Canthotomy

These complications can include

  • Eye damage caused by mechanical force (e.g., damage to the lateral rectus muscle lacrimal gland or the lacrimal artery) or the lids
  • Infection
  • Hemorrhage

The urgency of the process, combined with traumatic distortion of the anatomy and possible unfamiliarity with the process by non-ophthalmologists, may increase the risk of iatrogenic injury to the eyeball.

Equipment for Lateral Canthotomy

  • Gauze for sterile use, gloves, and drapes
  • Antiseptic solution (e.g., chlorhexidine, povidone Iodine)
  • Ocular topical anesthetic (e.g., 0.5% proparacaine or tetracaine eye drops)
  • Local anesthetic (e.g., 1 of lidocaine, or even 2% containing Epinephrine) Small needles for injection and a small (about 3 milliliters) Syringe
  • Ophthalmic antibiotic Ointment (e.g., Erythromycin 0.5 percent or Bacitracin)
  • At times, it is ordinary salt is used or water used for irrigation
  • Hemostat or needle holder toothed forceps Iris scissors

Additional Considerations for Lateral Canthotomy

  • The speed at which the diagnosis of OCS and the time to perform the procedure of canthotomy or cantholysis is essential to limit the length of time that retinal ischemia occurs. Ophthalmologic consultation is recommended, but it should not hinder the process. Since diagnosing OCS is solely a clinical diagnosis, The procedure must not be delayed due to imaging tests.
  • A technique for sterile is required.
  • The system can be extremely painful. A confused, conscious, or uncooperative patient might need a regional nerve block or sedation to avoid movement, which could cause eyeball injury while performing the surgery. Children might require general anesthesia while in an operating space.

Positioning for Lateral Canthotomy

  • Supinate the patient on the stretcher and support the patient’s eyes and head.

Relevant Anatomy for Lateral Canthotomy

  • The medial and the lateral canthal ligaments protect the eye within the orbit and eyelids.
  • The lateral tendon of the canthal has two branches: a superior one and an inferior one. The cutting of one or both opens the eyelids. It allows the eye to stretch outside of the orbit, thereby easing pressure on the eye.

Step-by-Step Description of Procedure

  • The initial steps must be completed as swiftly as possible, including an initial estimation of the visual ability and a thorough examination for the world, as well as, in some cases, an easy clean and irrigation for the canthus lateral region.
  • Set all your equipment on a tray at the headboard of your bed so that everything is easily accessible and you do not require to call for help.
  • Cleanse the skin using an antiseptic like chlorhexidine or povidone Iodine. Don’t allow the antiseptic to penetrate the eye. Apply a thin layer of the skin.
  • Inject 1 to 2 milli-liter of local anesthetic with Epinephrine in the lateral incision location.
  • Use a needle driver or hemostat to break the tissue from the lateral canal until the rim of your orbit, which can take anywhere from 20 to 2 minutes. By crushing this tissue, you can reduce bleeding and help discern where to cut when there is an extensive trauma-related swelling.
  • Cut with iris scissors from the lateral canthus up to the outer rim of the orbit, approximately 1 to 2 centimeters (canthotomy).
  • Cut the superior and occasionally both crusades of the canthal ligament in the lateral side (cantholysis). The majority of experts suggest starting with the lower crus. Lift the lateral area of the lower eyelid. With the scissors pointed toward the sun, determine and cut the more inferior crus. “Strumming” with the scissors could help you identify the more inferior crus. If the tendon remains intact, you’ll notice a twanging sound similar to an unplucked string.
  • Following that, some experts suggest cutting the superior crus every day. Others suggest reassessing the relief from OCS (e.g., taking measurements of your intraocular pressure) and cutting the superior crus only if OCS persists.
  • To cut off the superior crus, lift the eyelid and expose the lower part of the upper eyelid’s lateral side. Please verify that the tendon of the superior crus was cut by squeezing it with a pair of scissors.
  • If the tendon remains intact, you can cut it. Cutting the tendon opens the eyelid and eases pressure on the eyes more.

Aftercare for Lateral Canthotomy

  • Since the patient can’t blink to help lubricate the cornea, use an antibiotic-based ointment the eye, and cover it with a sterilized dressing.
  • Incisions for lateral canthotomy aren’t sutured during the canthotomy. They usually heal with no significant scarring.
  • Patients with severe injuries need to be treated in a hospital.
  • Methylprednisolone (i.e., 250 mg IM/IV every 6 hours) over three days must be considered in patients with progressive loss of vision.
  • If the intraocular pressure is still elevated, treatment with topical drops (e.g., the timolol 0.5 percent and Brimonidine 0.2 percent or dorzolamide two drops for the eyes at 2%) or systemic therapy (e.g., acetazolamide immediately-release 500 mg PO or mannitol 1-2 mg/kg IV over 45 minutes) is recommended.
  • Patients should not strain and apply the ice pack for several days after canthotomy.

Warnings and Common Errors of Lateral Canthotomy

  • If a globe rupture is suspected, you should avoid checking intraocular pressure or touching the globe.

Tips and Tricks for Lateral Canthotomy

  • When cutting the lower crus and aiming anteroposteriorly towards the lateral edge, ensure that you do not injure the levator muscles, the lacrimal gland, and the lacrimal artery, all of which are located above.

Anatomy

The medial canthal ligament and the lateral canthal ligament ensure that the eye stays inside the orbit. The lateral tendon, the subject of this manual, has a superior crus (branch) and an inferior crus.

The cutting of the lower crus reduces intraorbital pressure by releasing the lower eyelid, permitting the globe to expand beyond the orbit. Sometimes the superior crus can cut to relieve tension in the intraorbital area.

Indications

Lateral canthotomy must be done as an emergency treatment for orbital compartment syndrome. It manifests as an increase in IOP (IOP) and decreased extraocular mobility. Often, this condition happens in conjunction with the trauma to the orbit or eye surgery.

The most common indications for immediate canthotomy are sudden loss of vision or pupillary afferent defect in the context of retrobulbar hemorrhage that is proptosis-related and IOP over 40 mm Hg.

Contraindications

The procedure should not be done in patients with suspected open globes that could present with corneal laceration or positivity Seidel signs, hyphema, an irregularly-shaped pupil, and herniated uveal tissues or even a narrow anterior chamber.

Equipment

The equipment required to perform lateral canthotomy or cantholysis includes:

  • Gauze, gloves made of sterile material and face shields, gowns, and drapes
  • Solution for an antiseptic (chlorhexidine as well as Betadine)
  • Anesthetic local (lidocaine 1-2 1 % with epinephrine)
  • Syringe (3 milliliters) with needles for small injections (27- 30 gauge)
  • Irrigation fluid (normal water or saline)
  • A straight hemostat or needle driver (battery cautery, if available)
  • Sterile eye or suture scissors
  • Forceps (at 0.3 millimeters teeth)
  • Ointment for antibiotics (erythromycin 5percent or bacitracin)

Patient Positioning

Patients should lie on their backs, supine, with the head of the mattress slightly raised, at approximately 10-20o. They should also have their eyes and heads stabilized to avoid iatrogenic injuries throughout the process.

Procedure Instructions

  1. Begin by examining the globe, and then estimate roughly the visual clarity.
  2. Clean and rinse the canthus lateral area. Clean the area using antiseptic chlorhexidine, Betadine, and then drape.
  3. Inject 1 to 2 milli-liter of local anesthetic containing the epinephrine injection into the incision area you intend to use. When injecting, keep the needle’s tip away from the globe.
  4. Utilizing a needle driver or hemostat, make an approximate path for your cut from the lateral canthus towards the outer rim of your orbit. Lock the hemostat for 20 seconds to one minute to crush the tissue. This aids in hemostasis. While placing the instrument in the correct position, you should be able to feel the lower jaw of the needle driver/hemostat against the boney orbital rim. Once the tissues have been crushed, remove the needle/hemostat.
  5. To perform the canthotomyprocedure, cut the canthus lateral towards the edge of your orbit with iris scissors following the same path as the crushed tissue created in the earlier step. The total length of the incision should be between 1 and 2 centimeters. Be aware that the maximum size of the cut must not exceed 2 centimeters because the temporal branch of the facial nerve is located in the area. It is one nerve with no anastomosis.
  6. Lift the lateral side of the lower eyelid so that it exposes the superior tendon. To perform cantholysis, you must identify cuts in the inferior part of the ligament. Make sure that the scissors are pointed away from the globe when you cut.

Tips and Tricks

They are finding that the inferior crus on the lateral canthal tendon may occasionally be challenging. Cut it with scissors and “strum” the area to detect the inferior crus.

If you sense tension (like an unplucked string), it means that the tendon remains intact and must be removed.

When performing cantholysis, cut anteroposteriorly towards the lateral edge to prevent injuries to the surrounding structures superior to it, like the levator muscles, the lacrimal gland, and the artery.

In certain situations, the superior crus can be cut to alleviate pressure on the intraorbital region. To do this, raise and expose the lower portion of the upper eyelid’s lateral side and then make the cut superoposteriorly.

Follow-up

Incisions for lateral canthotomy typically are not required to be sutured and heal themselves independently, with little or no scarring. Patients cannot blink to moisturize the cornea following a canthotomy.

Therefore, ensure that you apply an antibiotic Ointment (e.g., erythromycin 5percent) onto the eye and then cover it with a sterile dressing to keep infection at bay.

Ice packs can be applied during the following days after the canthotomy procedure to ease discomfort and inflammation.

Case

A managed 21 was doing his business at a corner when suddenly two guys leaped at him. The primary injury is believed to be in the right eye. He’s experiencing lots of eye pain as well as blurred vision.

When you examine him, you notice the presence of proptosis, as well as an afferent pupillary deficiency. The ophthalmologist is working at a different hospital and is at most an hour away. However, he advises you to proceed with the canthotomy in the lateral direction.

Equipment

  • Chlorhexadine
  • Lidocaine (with epi)
  • Needle and syringe to administer lidocaine injection
  • Straight mosquito hemostat
  • Iris scissors
  • Forceps

My method of the lateral canthotomy

Define the risks and benefits.

Think about sedation when it is needed.

Cleanse the skin using chorhexadine.

Inject local anesthetics from the lateral canthus until the rim of the orbital. (Ignore that needle on the photo. The hand ought to be directed to the side of the planet.)

Infuse the eye by using saline to eliminate any obstructions.

Place a unidirectional mosquito hemostat across the lateral canthus. There is an end prong against your orbit and one prong being affixed to the skin. The tissue is compressed for 1 minute to stop bleeding.

In the same direction along this path, cut each layer of tissue using the Iris cutting blades.

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