Ординатура / Офтальмология / Английские материалы / Clinical Ophthalmology A Systematic Approach 7th Edition_Kanski, Bowling_2011

kanski 7th

Chapter 21 – Trauma

EYELID TRAUMA 872 Periocular haematoma  872

Laceration 872

ORBITAL FRACTURES 873 Blow-out orbital floor fracture  873

Blow-out medial wall fracture  875

Roof fracture 875 Lateral wall fracture 877

TRAUMA TO THE GLOBE 877 Introduction 877

Blunt trauma 878

Shaken baby syndrome 885 Penetrating trauma 885 Superficial foreign bodies  886

Intraocular foreign bodies  888

Enucleation 891 Bacterial endophthalmitis  891

CHEMICAL INJURIES 891 Causes 891 Pathophysiology

 891

Management 892

Eyelid trauma

Periocular haematoma

A ‘black eye’, consisting of a haematoma (focal collection of blood) and/or periocular ecchymosis (diffuse bruising) and oedema is the most common blunt injury to the eyelid or forehead and is generally innocuous. It is, however, very important to exclude the following more serious conditions:

1Trauma to the globe or orbit. It is easier to examine the integrity of the globe before the lids become oedematous (Fig. 21.1A). Once oedema is established, gentle sustained pressure to open the lids will often displace oedema sufficiently to allow visualization of the anterior segment; it is critical not to allow any force on the globe itself until its integrity has been confirmed.

2Orbital roof fracture, especially if the black eye is associated with a subconjunctival haemorrhage without a visible posterior limit (Fig. 21.1B).

3 Basal skull fracture, which may give rise to characteristic bilateral ring haematomas (‘panda eyes’ – Fig. 21.1C).

1109 / 1137

kanski 7th

Fig. 21.1 (A) Periocular haematoma and oedema; (B) periocular haematoma and subconjunctival haemorrhage; (C) ‘panda eyes’

(Courtesy of R Bates – fig. A)

Laceration

The presence of a lid laceration, however insignificant, mandates careful exploration of the wound and examination of the globe. Any lid defect should be repaired by direct closure whenever possible, even under tension, since this affords the best functional and cosmetic results.

1Superficial lacerations parallel to the lid margin without gaping can be sutured with 6-0 black silk; the sutures are removed after 5 days.

2Lid margin lacerations invariably gape and must therefore be very carefully sutured with perfect alignment to prevent notching as follows (Fig. 21.2A and B).

aPass a 5-0 silk vertical mattress suture in the plane of the meibomian gland orifices about 2 mm from the wound edges and 2 mm deep, and leave untied.

b Close the tarsal plate with partial-thickness lamellar 5-0 Vicryl (polyglactic acid) sutures and tie the sutures anteriorly. c Tie the silk suture so that the cut edges slightly pucker but leave the suture long.

dClose the overlying skin with interrupted 7-0 nylon or Vicryl sutures incorporating the tag ends of the silk suture to keep its knot away from the cornea.

3Lacerations with mild tissue loss just sufficient to prevent direct primary closure can usually be managed by performing a lateral cantholysis in order to increase lateral eyelid mobility.

4Lacerations with extensive tissue loss may require major reconstructive procedures such as are used following lid resection for malignant tumours (see Ch. 1).

5Canalicular lacerations should be repaired within 24 hours. The laceration is bridging by silicone tubing (Crawford), which is threaded down the lacrimal system and tied in the nose, following which the laceration is sutured. Alternatively, repair of a single canaliculus is performed by using a monocanalicular stent (e.g. Mini Monoka) and, if necessary, securing its footplate to the lid using 8-0 suture material. The tubing is left in situ for 3–6 months.

1110 / 1137

kanski 7th

Fig. 21.2 Repair of lid laceration. (A) Initial approximation of the tarsal plate with an absorbable suture and lid margin with a silk suture; (B) completed repair

(Courtesy of J Nerad, K Carter and M Alford, from Oculoplastic and Reconstructive Surgery, in Rapid Diagnosis in Ophthalmology, Mosby 2008)

It is very important to ensure that the patient's tetanus immunization status is satisfactory after any injury. Without any prior immunization (unlikely) give 250 units of human tetanus immunoglobulin intramuscularly (IM); if previously immunized but a booster has not been administered within the last 10 years, give IM or subcutaneous tetanus toxoid.

Copyright © 2011 Elsevier Inc.All rights reserved. Read our Terms and Conditions of Use and our PrivacyPolicy.

If you find this useful please saythanks in your way: dramroo

1111 / 1137

kanski 7th

Orbital fractures

Blow-out orbital floor fracture

A blow-out fracture of the orbital floor is typically caused by a sudden increase in the orbital pressure by an impacting object which is greater in diameter than the orbital aperture (about 5 cm), such as a fist or tennis ball (Fig. 21.3), so that the eyeball itself is displaced and transmits rather than absorbs the impact. Since the bones of the lateral wall and the roof are usually able to withstand such trauma, the fracture most frequently involves the floor of the orbit along the thin bone covering the infraorbital canal. Occasionally, the medial orbital wall may also be fractured; a ‘pure’ blow-out fracture does not involve the orbital rim whereas an ‘impure’ fracture involves the rim and/or adjacent facial bones. Clinical features vary with the severity of trauma and the time interval between injury and examination.

Fig. 21.3 Mechanismof an orbital floor blow-out fracture

Diagnosis

1Periocular signs include variable ecchymosis (Fig. 21.4A), oedema and occasionally subcutaneous emphysema.

2Infraorbital nerve anaesthesia involving the lower lid, cheek, side of nose, upper lip, upper teeth and gums is very common because the fracture frequently involves the infraorbital canal.

3Diplopia may be caused by one of the following mechanisms:

•Haemorrhage and oedema in the orbit may cause the septa connecting the inferior rectus and inferior oblique muscles to the periorbita to become taut and thus restrict movement of the globe. Ocular motility usually improves as the haemorrhage and oedema resolve.

•Mechanical entrapment within the fracture of the inferior rectus or inferior oblique muscle, or adjacent connective tissue and fat. Diplopia typically occurs in both upgaze (Fig. 21.4B) and downgaze (double diplopia). In these cases forced duction and the differential intraocular pressure tests are positive. Diplopia may subsequently improve if it is mainly due to entrapment of connective tissue and fat, but usually persists if there is significant involvement of the muscles themselves.

•Direct injury to an extraocular muscle is associated with a negative forced duction test. The muscle fibres usually regenerate and normal function returns within about 2 months.

4Enophthalmos (Fig. 21.4C) may be present if the fracture is severe, although it tends to manifest only after a few days as the initial oedema resolves. In the absence of surgical intervention, enophthalmos may continue to increase for about 6 months as posttraumatic orbital degeneration and fibrosis develop.

5Ocular damage (e.g. hyphaema, angle recession, retinal dialysis), although relatively uncommon, should be excluded by slit-lamp and fundus examination.

6CT with coronal sections (Fig. 21.4D) is particularly useful in evaluating the extent of the fracture, as well as determining the nature of maxillary antral soft-tissue densities which may represent prolapsed orbital fat, extraocular muscles, haematoma or unrelated antral polyps.

7 Hess test (Fig. 21.5) is useful in assessing and monitoring the progression of diplopia.

1112 / 1137

kanski 7th

Fig. 21.4 Right orbital floor blow-out fracture. (A) Mild bruising and superficial laceration; (B) restricted elevation; (C) mild enophthalmos; (D) CTcoronal view shows a defect in the orbital floor (arrow) and the ‘tear drop’ sign in the antrum

(Courtesy of A Pearson – fig. D)

Fig. 21.5 Hess chart of a left orbital floor blow-out fracture shows restriction of left upgaze (superior rectus and inferior oblique) and restriction on downgaze (inferior rectus). There is also secondary overaction of the right eye

Treatment

1Initial treatment is conservative with antibiotics; ice packs and nasal decongestants may be helpful. The patient should be instructed not to blow the nose, because of the possibility of forcing infected sinus contents into the orbit. Systemic steroids are occasionally required for severe orbital oedema, particularly if this is compromising the optic nerve.

2Subsequent treatment is aimed at prevention of permanent vertical diplopia and/or cosmetically unacceptable enophthalmos. The three factors that determine the risk of these late complications are fracture size, herniation of orbital contents into the maxillary sinus and muscle entrapment. Although there may be some overlap, most fractures fall into one of the following categories:

•Small cracks unassociated with herniation do not require treatment as the risk of permanent complications is small.

•Fractures involving up to one-third of the orbital floor, with little or no herniation, no significant enophthalmos and improving diplopia, also do not require treatment.

•Fractures involving more than one-third of the orbital floor will usually develop significant enophthalmos if left untreated.

•Fractures with entrapment of orbital contents, enophthalmos of greater than 2 mm, and/or persistent and significant diplopia in the primary position should be repaired within 2 weeks. If surgery is delayed, the results are less satisfactory due to secondary fibrotic changes.

•A subgroup, the ‘white-eyed’ fracture, requires urgent repair to avoid permanent neuromuscular damage. This is generally seen in patients less than 18 years of age, typically with little visible external soft tissue injury, and usually affects the orbital floor. It involves the acute incarceration of herniated tissue in a trap-door effect which occurs due to the greater elasticity of bone in younger people. Patients may experience acute nausea, vomiting, and headache; persistent activation of the oculocardiac reflex can occur. CT features may be subtle as the orbital floor often appears intact.

•Early marked enophthalmos may also be an indication for urgent repair.

3Technique of surgical repair

a A transconjunctival or subciliary incision is made (Fig. 21.6A).

bThe periosteum is elevated from the floor of the orbit and all entrapped orbital contents are removed from the antrum (Fig.

1113 / 1137

kanski 7th

21.6B).

c The defect in the floor is repaired by using synthetic material such as Supramid®, silicone or Teflon® (Fig. 21.6C).

dThe periosteum is sutured (Fig. 21.6D).

Fig. 21.6 Technique of repair of an orbital floor blow-out fracture

Blow-out medial wall fracture

Medial wall orbital fractures are usually associated with floor fractures; isolated fractures are less common.

1Signs

•Periorbital ecchymosis (Fig. 21.7A) and frequently subcutaneous emphysema, which typically develops on blowing the nose.

•Defective ocular motility involving abduction (Fig. 21.7B) and adduction (Fig. 21.7C), if the medial rectus muscle is entrapped in the fracture.

2CT will show the extent of damage (Fig. 21.7D).

3Treatment involves release of entrapped tissue and repair of the bony defect.

Fig. 21.7 Blowout fracture of the left medial wall and floor. (A) Periorbital haematoma and ptosis; (B) defective left abduction; (C) defective left adduction; (D) CT coronal view shows fractures of the medial wall (red arrow) and floor (white arrow)

(Courtesy of A Pearson)

Roof fracture

Roof fractures are rarely encountered by ophthalmologists. Isolated fractures, caused by falling on a sharp object (Fig. 21.8) or a blow to the brow or forehead, are most common in children. Complicated fractures, caused by major trauma with associated displacement of the orbital rim or significant disturbance of other craniofacial bones, typically affect adults.

1114 / 1137

kanski 7th

1Presentation is with a haematoma of the upper eyelid and periocular ecchymosis which develop after a few hours and may later spread to the opposite side (see Fig. 21.1C).

2Signs

•Inferior or axial displacement of the globe.

•Large fractures may be associated with pulsation of the globe, best detected on applanation tonometry, due to transmission of CSF pressure.

3Treatment

•Small fractures may not require treatment but it is important to exclude a CSF leak as this carries a risk of meningitis.

•Sizeable bony defects with downward displacement of fragments usually require reconstructive surgery.

Fig. 21.8 Pre-operative image of a patient with a roof fracture caused by a ball-point pen

(Courtesy of R Bates)

Lateral wall fracture

Acute lateral wall fractures are rarely encountered by ophthalmologists. Because the lateral wall of the orbit is more solid than the other walls, a fracture is usually associated with extensive facial damage (Fig. 21.9).

1115 / 1137

kanski 7th

Fig. 21.9 Lateral wall fracture. (A) Severe facial trauma; (B) CTaxial view shows a left lateral wall fracture

(Courtesy of A Pearson)

Copyright © 2011 Elsevier Inc.All rights reserved. Read our Terms and Conditions of Use and our PrivacyPolicy.

If you find this useful please saythanks in your way: dramroo

1116 / 1137

kanski 7th

Trauma to the globe

Introduction

Definitions

1 Closed injury is commonly due to blunt trauma. The corneoscleral wall of the globe is intact.

2Open injury involves a full-thickness wound of the corneoscleral envelope.

3Contusion is a closed injury resulting from blunt trauma. Damage may occur at or distant to the site of impact.

4Rupture is a full-thickness wound caused by blunt trauma. The globe gives way at its weakest point, which may not be at the site of impact.

5 Laceration is a full-thickness defect in the eye wall produced by a tearing injury, usually as the result of a direct impact.

6Lamellar laceration is a partial-thickness laceration.

7Incised injury is caused by a sharp object such as glass or a knife.

8Penetrating injury refers to a single full-thickness wound, usually caused by a sharp object, without an exit wound. A penetrating injury may be associated with intraocular retention of a foreign body.

9Perforation consists of two full-thickness wounds, one entry and one exit, usually caused by a missile.

Principles of evaluation

1Initial assessment should be performed in the following order:

a Determination of the nature and extent of any life-threatening problems.

b History of the injury, including the circumstances, timing and likely object. c Thorough examination of the eyes and the orbits.

2Special investigations

a Plain radiographs may be taken when a foreign body is suspected (Fig. 21.10A).

bCT is superior to plain radiography in the detection and localization of intraocular foreign bodies (Fig. 21.10B). It is also of value in determining the integrity of intracranial, facial and intraocular structures.

cMR is more accurate than CT in the detection and assessment of injuries of the globe itself such as an occult posterior rupture, though not for bony injury. MRI should never be performed if the presence of a ferrous metallic foreign body is suspected.

dUS may be useful in the detection of intraocular foreign bodies (Fig. 21.10C), globe rupture, suprachoroidal haemorrhage and retinal detachment; it should be performed as gently as possible if there is a risk of an open globe injury, strictly avoiding any pressure on the globe. It is also helpful in planning surgical repair, for example regarding placement of infusion ports during vitrectomy and whether drainage of suprachoroidal haemorrhage is required.

eElectrodiagnostic tests may be useful in assessing the integrity of the optic nerve and retina, particularly if some time has passed since the original injury and there is suspicion of a retained intraocular foreign body.

1117 / 1137

kanski 7th

Fig. 21.10 Imaging of foreign bodies. (A) Plain radiograph shows an air gun pellet; (B) CTaxial view shows a left intraocular foreign body; (C) US shows an intraocular foreign body

Blunt trauma

The most common causes of blunt trauma are squash balls, elastic luggage straps and champagne corks. Severe blunt trauma to the globe results in anteroposterior compression with simultaneous expansion in the equatorial plane (Fig. 21.11) associated with a transient but severe increase in intraocular pressure. Although the impact is primarily absorbed by the lens-iris diaphragm and the vitreous base, damage can also occur at a distant site such as the posterior pole. The extent of ocular damage depends on the severity of trauma and tends largely to be concentrated to either anterior or posterior segment. Apart from obvious ocular damage, blunt trauma commonly results in long-term effects; the prognosis is therefore necessarily guarded.

Fig. 21.11 Pathogenesis of ocular damage by blunt trauma

Corneal

1118 / 1137