Fractures of the Skull

Chapter 96 Fractures of the Skull



Mark M. Smith


Fractures of the zygomatic arch require surgery if they interfere with mastication or compress ocular structures. The most common extracranial fracture requiring surgery is a depression fracture of the frontal sinus. Intracranial fractures that require surgery are those that depress into brain parenchyma, causing significant compromise of cerebral function. Most skull fractures are amenable to conservative management.


Weigh the complications of general anesthesia in a neurologically compromised patient against the positive effects of surgical intervention. Fine motor movement is not necessarily required of small animal pets; therefore, intracranial surgery rarely is performed.



ANATOMY



Zygomatic Arch



• The cranial portion of the zygomatic arch is formed by the zygomatic bone, and the caudal portion is formed by the zygomatic process of the temporal bone.

• The zygomatic arch forms the ventral and lateral rim of the orbit.


Calvarium



• The dorsal sagittal crest courses craniocaudal over the calvarium.

• The nuchal crest courses mediolateral over the caudal edge of the skull.

• The frontal sinus of the frontal bone comprises the frontal encasement of the brain.

• The diploic calvarium has two distinct cortical bone layers between which is an interstitial layer of honeycombed bone and vessels.

• The brain is encased by the frontal, parietal, temporal, and occipital bones.

• The temporalis muscles cover almost the entire calvarium.


ZYGOMATIC ARCH FRACTURE



Preoperative Considerations



• Before anesthesia and surgery, perform a complete neurologic examination on all head trauma patients.

• General anesthesia may alter intracranial pressure (ICP), leading to exacerbation of intracranial edema and/or hemorrhage.

• To reduce ICP, consider hyperventilation (to reduce PaCO2), osmotic agents, corticosteroids, and an anesthetic protocol including barbiturates (see Chapter 2).

• Obtain skull radiographs to document fracture displacement and to screen for other, less apparent fractures. If possible, perform radiography immediately before surgery, thus avoiding the necessity for, and risk of, two separate anesthetic procedures.

• If available, computed tomography (CT) provides the most accurate assessment of the presence and severity of skull and cranial fractures. CT views avoid superimposition of overlying bone that makes the interpretation of plain skull radiographs difficult.

• Confirm the presence of an intact optic nerve and vision before surgery. Surgery for a zygomatic arch fracture may be contraindicated if ocular function is irreversibly impaired.



Key Point


Acepromazine may lower the central nervous system (CNS) seizure threshold, and ketamine increases cerebral blood flow. Do not use these drugs in patients with a history of brain trauma.



Surgical Procedure



Objectives



• Reduce fractures that can cause compression of the eye or cosmetic deformity.

• Avoid trauma to the zygomaticotemporal and zygomaticofacial nerves.



Key Point


Non-displaced fractures of the zygomatic arch have a good prognosis for uncomplicated healing with conservative management.



Equipment



• Standard general surgical pack and sutures

• Gelpi or Weitlaner self-retaining retractors

• Sharp periosteal elevator

• Small Steinmann pins and orthopedic wire (multiple sizes, 18–24 gauge)

• Small malleable retractor


Technique



1. Place the patient in ventral recumbency with the head supported. Attach tape to the mandibular canines and the table to secure the head position.

2. Prepare the periocular area for aseptic surgery. Ocular lubricating ointment avoids corneal damage from antiseptic agents.

3. Incise the skin directly over the zygomatic arch.

4. Incise and elevate the periosteum using a sharp periosteal elevator. Be careful to avoid the zygomaticotemporal and zygomaticofacial nerves (medial to the zygomatic bone).

5. Use a small malleable retractor to protect the orbit.

6. Reduce and secure fracture fragments using orthopedic wire (18–24 gauge, depending on the size of the animal). Small pins may be used to make holes in the bone for wire placement. Small orthopedic plates may be required to maintain reduction in extremely comminuted fractures or when cosmesis is of paramount importance.

Related posts:

  1. Feline Infectious Peritonitis (Feline Coronavirus)
  2. Borreliosis (Lyme Disease)
  3. Immune-Mediated Dermatoses
  4. Otitis Media and Otitis Interna

Stay updated, free articles. Join our Telegram channel
Tags:
Aug 27, 2016 | Posted by in SMALL ANIMAL | Comments Off on Fractures of the Skull

Full access? Get Clinical Tree
Get Clinical Tree app for offline access