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Rib: fracture

ISSN 2398-2977

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Introduction

  • Cause: blunt thoracic trauma to foal during birth or collision, blow or kick in the adult.
  • History: foals recently born to primiparous mares, dystocic parturition or in adults following blunt thoracic trauma with difficulty in breathing.
  • Signs: contusions and rib fractures may → pain, pulmonary compromise and secondary complications, eg flail chest, pneumothorax, hemothorax.
  • Diagnosis: ultrasonography, radiography and nuclear scintigraphy help confirm diagnosis.
  • Treatment: many cases apparently remain subclinical and will heal without specific treatment or complications, but pain control and supportive care are important especially in neonatal foals. Surgical stabilization is useful in some cases.
  • Prognosis: depends on age of patient, degree of damage and secondary complications but varies from guarded to good.

Presenting signs

Neonates

  • Many cases are subclinical.
  • Born to mares following dystocia or primiparous birth. Size of foal not always significant.
  • Difficulty in breathing.
  • Palpable rib pain +/- deformity/fracture.
  • Usually unilateral, 1-5 ribs.
  • Sudden death.
  • Flail chest and other complications are rare.

Adults

  • Blunt thoracic trauma - falls, collisions, kicks.
  • Difficulty in breathing and painful chest on palpation.
  • Deformation of thoracic wall and/or rib fractures.
  • Other injuries to soft tissues, pneumothorax Pneumothorax and hemothorax.

Acute presentation

  • Difficulty breathing.
  • Swelling over thorax.
  • Thoracic wounds in adult cases Thorax trauma.

Age predisposition

  • Common in neonatal foals.
  • Adults.

Breed/Species predisposition

  • Larger breed foals.

Cost considerations

  • Costs of diagnosis and treatment.

Special risks

Pathogenesis

Etiology

  • Birth-related, blunt, thoracic trauma due to excessive or incorrect force applied to foal during passage through the birth canal. There is increased incidence in fetal oversize or dystocia foals. In one study 263 foals were examined within 3 days of birth and 55 (21%) had evidence of blunt thoracic trauma that had occurred during parturition.
  • Collision with objects, falls or kicks, may cause blunt or penetrating thoracic trauma in older animals. Blunt trauma is associated with pulmonary contusions and rib fractures whereas penetrating injuries (more common) may → pneumo- or hemothorax.
  • Excessive chest compression during cardiopulmonary resuscitation Emergency resuscitation is less likely in neonatal foals because of compliant nature of ribs.

Predisposing factors

General

  • Thoracic trauma.

Specific

  • Dystocia.
  • Fetal oversize.
  • Incorrect obstetric techniques.

Pathophysiology

  • Blunt thoracic trauma at birth or by collisions/falls, etc.
  • Abnormalities at birth predispose foals to rib fractures.
  • Fractures are usually at or near the costochondral junction of the ribs in the cranial and ventral half of the thorax (ribs 3-8). Left and right sides are equally affected.
  • Fractures on the left side between ribs 3 and 6, at the costochondral junction, may carry a greater risk due to their proximity to the heart.
  • Rib fractures may be subclinical or → painful breathing, pulmonary compromise and cardiovascular embarrassment.
  • Secondary complications including damage to vital structures (cardiac and lung laceration), pneumothorax Pneumothorax and hemothorax, diaphragmatic hernia Diaphragm: hernia, flail segment, respiratory distress and sudden death.
  • Blunt trauma often → contusions and rib fractures.
  • The resultant rib fractures can lacerate the pulmonary parenchyma or perforate the heart/cardiac vessels/large vessels. Also been associated with diaphragmatic hernias Diaphragm: hernia.
  • Secondary hemothorax and/or pneumothorax may occur.
  • Major concerns are the possibility of cardiovascular embarrassment, pain and pulmonary compromise → inadequate ventilation and oxygenation Respiratory: nasal oxygen administration.
  • Hypoventilation may progress to hypercarbia, hypoxia and infection compounding the problem and → adult respiratory distress syndrome.

Diagnosis

Presenting problems

  • Dyspnea.
  • Chest pain.

Client history

Neonates

  • Foals born to mares with dystocia Reproduction: dystocia or primiparous births.
  • Size of foal (weight or thoracic circumference) are probably not significant factors.
  • Many cases are subclinical in foals.
  • Very high incidence in foals presented for intensive care.
  • Difficulty breathing.
  • Sudden death or collapse due to damage within the thoracic cavity.

Adults

  • Blunt trauma to the chest - falls, collisions, kicks.
  • Difficulty in breathing.
  • Evidence of painful chest or pain on palpation.
  • Penetrating trauma.
  • Lameness (1-6/10).
  • Resistance when ridden.

Clinical signs

Foals

  • Frequently subclinical.
  • Groaning during respiration.
  • Other problems that may be associated with rib fractures include:
    • Pericardial/cardiac lacerations.
    • Ex-sanguination.
    • Lung laceration.
    • Pneumothorax Pneumothorax.
    • Hemothorax.
    • Diaphragmatic hernia Diaphragm: hernia.
    • Pulmonary contusions.
    • Peracute death.
  • Palpation of ribs whilst foal standing will reveal areas of pain, swelling, asymmetry of the thoracic cavity, subcutaneous crepitation and possible fractures. Very detailed careful palpation may identify non-displaced fractures and occasionally crepitus.
  • Thoracic cage asymmetry is best appreciated with the foal in dorsal recumbency.
  • Usually unilateral fractures over the cranial rib cage at the costochondral junction or immediately dorsal to it.
  • Between 1-5 fractured ribs often adjacent to each other.
  • Costochondral dislocations can occur and are less serious.
  • Flail chest +/- pulmonary contusions:
    • Three or more adjacent ribs fractured in 2 places resulting in a loss of stability of an area of chest wall (flail segment).
    • In neonates the costochondral junction, which is very flexible, can mimic one of the 2 fracture planes.
    • Free-floating segment with paradoxical movement:
      • During inspiration the affected region of the thorax may become depressed and then bulge outward during exhalation.
      • Rare in adults.
  • Rapid death.

Adults

  • Painful ribs → conscious limitation of respiratory excursion.
  • Pain on palpation of ribs.
  • Palpable fractures and/or deformation of thoracic wall.
  • Associated soft tissue injuries.
  • Subcutaneous emphysema.
  • Signs of pneumothorax Pneumothorax and/or hemothorax.
  • Lameness, resistance to ridden exercise, bolting/bucking, poor performance Poor performance: overview or back pain Musculoskeletal: back pain.
  • Rapid death.
  • In one survey of 66 cases:
    • Most commonly affected rib was T18 followed by T10. The left side was twice as commonly affected as the right.
    • All other ribs were affected with fractures except T2, T3 and T4.
    • T1 was affected in 5 racing Thoroughbreds Thoroughbred all of which presented with ipsilateral forelimb lameness. It was postulated that these may represent fatigue fracture pathology.

Diagnostic investigation

Palpation of thorax

  • Careful palpation over the whole thorax and specifically along the line of the individual ribs may reveal soft tissue swelling, focal pain, crepitus, and bony contour disparity.

Ultrasonography

  • Fracture lines and degree of displacement identified Ultrasonography: bone / joints:
    • Much more accurate in detecting fractures than radiography.
    • Most foals have at least 2 fractured ribs and ribs 2-7 are most likely to be affected (4th rib most common).
    • Cranial ribs are more difficult to assess due to increased covering of soft tissues.
  • Identification of damage to pleura, lung, heart and vessels as well as pleural fluid Ultrasonography: thorax.

Nuclear scintigraphy

  • Can be a useful diagnostic tool Bone: scintigraphy, particularly in the adult horse presenting with ridden/poor performance issues.

Radiography

  • Can be difficult to identify especially in adults and when non-displaced Thorax: radiography.

Diagnostic analgesia

  • Placing local anesthetic Anesthesia: local adjacent to rib fractures and assessing the subsequent clinical presentation may be used to determine their significance.

Pleurocentesis

  • Usually blood in uncomplicated cases.

Confirmation of diagnosis

Discriminatory diagnostic features

  • Clinical signs.

Definitive diagnostic features

Differential diagnosis

Treatment

Standard treatment

Neonates

Adults

  • Fractured ribs usually heal without fixation.
  • Displaced rib fractures may lacerate the lungs, heart, blood vessels, diaphragm, or other deep structures and also lead to flail chest syndrome. In these circumstances surgical rib fixation may be indicated to limit further thoracic injury:
    • Reported techniques for stabilizing rib fractures include the use of:
      • Quill sutures, external splints, pins, and wires.
      • Plate/screw and cerclage wire application.
      • Mylon cable tie fixation.
    • Where more severe rib damage prevents realignment, the remaining bone and fragments can be removed.
  • Non-steroidal anti-inflammatory medication systemically to relieve pain Therapeutics: anti-inflammatory drugs.
  • Exercise restriction for 3-6 months.
  • Perineural anesthesia of the intercostal nerves using long-acting local anesthetic such as bupivacaine Bupivacaine hydrochloride inserted around nerves between 1 rib space cranial to and 1 space caudal to the injuries.
  • Thoracic wounds should be thoroughly explored after patient stabilization:
    • If an open pneumothorax is present this should be covered by sterile, airtight dressings.

    General anesthesia Anesthesia: general - overview should be used with extreme caution.

    • After the wound is cleaned and debrided the degree of rib and other structure damage should be assessed.
    • Foreign bodies, including rib fragments, should be removed and sharp rib edges rongeured smooth to prevent further trauma to adjacent structures.
    • Primary wound closure should be attempted otherwise flaps, prosthetic meshes or moist dressing packing plus thorax bandages used.
    • Broad spectrum antibiotics Therapeutics: antimicrobials, NSAIDs Therapeutics: anti-inflammatory drugs and tetanus antitoxin Tetanus antitoxin should be administered.
  • Pneumothorax Pneumothorax.
  • Hemothorax.
  • Surgical stabilization in flail chest syndrome can be achieved by attaching the segment to an external splint of plastic or wood laid over the segment and secured to normal ribs cranially/caudally. Open reduction with stainless steel wire fixation of the fractures has been tried.

Prevention

Control

  • Attendance at parturition with careful use of obstetric techniques.

Outcomes

Prognosis

  • Good to guarded depending on age of patient, degree of damage and secondary complications.
  • In one paper, it was concluded that neonates with surgically repaired fractured ribs had a good prognosis for survival, and those that survived had similar chances of starting a race compared to maternal siblings.

Reasons for treatment failure

  • Complications of surgical stabilization include prosthesis or implant failure, post-operative displacement of the fracture ends and resulting damage to underlying structures, infection and seroma formation.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Alvarez A V et al (2022) Survival and racing performance after surgical treatment of rib fractures in foals. Vet Surg 51 (1), 62-67 PubMed.
  • Boullhesen Williams T et al (2017) Internal fixation of fractured ribs in neonatal foals with nylon cable tie using a modified technique. Can Vet J 58 (6), 579-581 PubMed.
  • Dahlberg J A et al (2011) Clinical relevance of abnormal scintigraphic findings of adult equine ribs. Vet Radiol Ultrasound 52 (5), 573-579 PubMed
  • Downs C & Rodgerson D (2011) The use of nylon cable ties to repair rib fractures in neonatal foals. Can Vet J 52 (3), 307-309 PubMed.
  • Jean D, Picandet V, Macieira S et al (2007) Detection of rib trauma in newborn foals in an equine critical care unit: a comparison of ultrasonography, radiography and physical examination. Equine Vet J 39 (2), 158-163 PubMed.
  • Kraus B M et al (2005) Multiple rib fracture in a neonatal foal using a nylon strand suture repair technique. Vet Surg 34 (4), 399-404 PubMed.
  • Bellezzo F et al (2004) Surgical repair of rib fractures in 14 neonatal foals: case selection, surgical technique and results. Equine Vet J 36 (7), 557-562 PubMed.
  • Schambourg M A et al (2003) Thoracic trauma in newborn foals: Post mortem findings. Equine Vet J 35 (1), 78-81 PubMed.
  • Jean D, Laverty S, Halley J, Hannigan D & Leville R (1999) Thoracic trauma in newborn foals. Equine Vet J 31 (2), 149-152 PubMed.
  • Rossdale P D (1999) Birth trauma in newborn foals. Equine Vet J 31 (2), 92 PubMed.