diaphragmatic hernia and injury

Diaphragmatic Hernia

Thorsang ChayovanChaiyapongse Tangsittitum

PGY2 Radiology

Outline

• Anatomy

• Embryology

• Anatomic variants

• Diaphragmatic hernias– Congenital: Bochdalek and Morgagni hernias, along

with diaphragmatic eventration, typically originate in utero from developmental weaknesses or defects in the diaphragm

– Acquired: Hiatal hernias and traumatic diaphragmatic rupture

Diaphragm: Anatomy

• Musculotendinous dome-shaped structure that demarcates pleural and peritoneal cavities.

• The 3 muscular components converge into the central tendon

– Pars lumbaris

– Pars costalis

– Pars sternalis

Diaphragm: Anatomy

• Gaps between muscle groups: pleura, peritoneum, and 2 fascial layers → potential weakness

A, Aortic hiatus; B, Bochdalek space; CT, central tendon; E, esophageal hiatus; IVC, caval hiatus; M, Morgagni space; L, Larrey space; PC, pars costalis; PL, pars lumbaris; PS, pars sternalis.

Diaphragm: Anatomy

• Innervation:

– Bilateral phrenic nerves (C3–C5)

– Lower intercostal nerves

• Arterial supply

– Internal thoracic artery

• Pericardiophrenic aa.

• Musculophrenic aa.

– Inferior phrenic arteries

Diaphragm: Embryology

Imaging of diaphragm

– Anatomic: All modalities

– Functional: Fluoroscopy, US, and MR fluoroscopy

Imaging of diaphragm: Radiography

• Normal

– Upper aspect: can see on frontal and lateral views

– Lower border: blend with the soft tissues

• Frontal

– Rt. dome: anterior sixth rib

– Lt. dome: usually 1 ICS lower than Rt.

• Lateral

– Anterior part of Lt. dome: obscured by cardiac shadow

– Rt. Hemidiaphragm: entirely seen

Imaging of diaphragm: Ultrasonography

• Thick echogenic line

• Portions of both domes can be seen together on an oblique transverse subxiphoid view obtained at midline: real-time assessment of the movement

• Individual domes can be assessed in parasagittal or coronal planes

Imaging of diaphragm: CT and MRI

• Excellent modalities(multiplanar capability and soft-tissue resolution)

• Multiplanar imaging: easier understanding of the orientation of anatomy and pathology

• MRI: excellent soft-tissue resolution

– Low signal intensity compared to skeletal muscles in all sequences

Imaging of diaphragm: CT and MRI

• Small children: crura are larger relative to body size and T12 vertebral body diameter + more chance of nodularity

Anatomic Variations

• Diaphragmatic slip

• Nodular crura

• Prominent (hypertrophic) median and lateral arcuate ligaments

Anatomic Variations: Diaphragmatic slip

• Common anatomic variant

• Folds or bundles of muscle run obliquely along inferior surface of diaphragm → fold or strip of muscle bundle protruding from inferior surface of diaphragm ± smooth indentation of liver or spleen

• Unilateral or bilateral, single or multiple

• Mimic mass, peritoneal implant, or LN

Anatomic Variations: Diaphragmatic slip

• CT: – Hypodense bands running obliquely along the inner

surface of the diaphragm

– Scalloped appearance diaphragm

– Diaphragm tends to bulge upward on either side of slips: mimic diaphragmatic hernia or weakness

• USG:– Echogenic(mimic intrahepatic mass)

– Deep inspiration increased prominence of the slips.

– Care must be taken to distinguish this normal anatomic variant from the array of true diaphragmatic defects.

Anatomic Variations: Nodular crura

• Hypertrophy or nodularity, especially in small children and during deep inspiration

Anatomic Variations: Prominent median and lateral arcuate ligaments

• 10%–24% of people

• Median arcuate ligament cross over proximal portion of celiac trunk → unique indentation

• Some have compressive symptoms of celiac a: postprandial epigastric pain and weight loss(median arcuate ligament syndrome or celiac artery compression syndrome)

Anatomic Variations: Prominent median and lateral arcuate ligaments

• CT or CTA

– Hooked appearance and narrowing of celiac trunk

– Rarely, lateral arcuate ligaments appears nodular: mimic lymph nodes and peritoneal deposits

Congenital and DevelopementalPathologic Conditions

• Congenital diaphragmatic hernia

• Eventration

• Aplasia/hypoplasia/accessory diaphragm

• Rarely, diaphragmatic abnormalities may be seen in association with congenital pulmonary venolobar syndrome, heterotaxy, and situsinversus

Accessory Diaphragm

• Fibromuscular membrane fused anteriorly with the diaphragm and coursing posterosuperiorly to join posterior chest wall

• May associated with other congenital anomalies: extralobar pulmonary sequestration, lobar agenesis or aplasia, and unilateral single pulmonary vein

Accessory Diaphragm

• Part of lung which trapped below accessory diaphragm was supplied by pulmonary vessels and bronchi that run through hole in accessory diaphragm

Accessory Diaphragm

Eventration

• Abnormal elevation of an intact hemidiaphragm into chest cavity

• Thought to be due to congenital absence of muscle fibers in region of eventration(however, lack of thinning fibers there)

• Other causes: focal dyskinesia and weakness from ischemia, infarct, or neuromuscular dysfunction

• Most common location: anteromedial aspect of Rt. Hemidiaphragm(usually occupied by part of liver)

• DDx

– Morgagni hernia

– pericardial cyst

– paraesophageal hernia

– bronchogenic cyst

– Tumor

• Complete eventration of a hemidiaphragm: more common in males and typically occurs on the left side

Bochdalek Hernia

• Posterolateral defect• Between pars costalis

and pars sternalis• Malformation of the

pleuroperitoneal fold • Failure of the

pleuroperitoneal fold and septum transversum to fuse properly with intercostal muscles

Bochdalek Hernia

• The most common CDH

• Mostly diagnosed at antenatal US or manifest at birth with respiratory distress

• 80% occurs on the left side

Bochdalek Hernia

• Asymptomatic

• Newborn: respiratory failure

• Age > 1 month: gastrointestinal symptoms– Rarely bowel incarceration, strangulation,

perforation, or shock.

• Hernias in this location of natural diaphragmatic weakness may also be acquired or exacerbated through trauma or physical exertion.

Bochdalek Hernia: imaging

• Discontinuity of the posterior or posteromedial diaphragm

• Protrusion of – Peritoneal or retroperitoneal fat through the defect– Less commonly, colon, small bowel, liver, spleen, or kidney

herniation

• DDx in radiograph: – Lipoma, lung or diaphragmatic tumors, neurogenic tumor,

intrathoracic kidney, or pulmonary sequestration.

• CT: the homogeneous fatty composition + discontinuity of the diaphragm

Morgagni Hernia

• An anterior opening

• Sternum medially(pars sternalis)

• Eighth rib laterally(pars costalis)

• Failure of fusion between the transverse septum and the lateral body wall

Morgagni Hernia

• 90% are right-sided

• Mostly detected in older children and adults

– Incidental

– Manifest as pulmonary infection or GI obstruction

• Anterior herniation of bowel loops on a lateral chest radiograph

Morgagni Hernia

• Neonates: liver, bowel, or stomach• Older children: bowel alone• Adults: omentum is common, and only rarely with

bowel, stomach, or liver – Women (61%)--average age of 58 years– Men--bimodal pattern of presentation, with a first peak at

31-35 years and 50-60 years

• If bilateral associated with pericardial defects and chromosomal anomalies

• Predisposing conditions ~ abdominal hernias – pregnancy, trauma, obesity, chronic constipation, and

chronic cough

Morgagni Hernia: imaging

• Radiograph: a fatty mass in the right cardiophrenic angle

– DDx prominent epicardial fat pad, other fat-containing masses (lipoma, teratoma, thymoma, thymolipoma, or liposarcoma)

• Displaced curvilinear omental vessels

– Within the “mass”

– Coursing across the diaphragmatic defect

Best appreciated with coronally reformatted CT or MR

Morgagni Hernia

• Morgagni hernia may occur as a component of the pentalogy of Cantrell

1. Omphalocoele2. Ectopia cordis (abnormal location of heart)3. Diaphragmatic defect4. Pericardial defect or sternal cleft5. Cardiovascular malformations

– ventricular septal defect (VSD)– atrial septal defect (ASD)– tetralogy of Fallot– left ventricular diverticulum

Congenital diaphragmatic hernias

• Physiologic abnormalities of the lungs

• Pulmonary hypoplasia

• Pulmonary hypertension

Congenital diaphragmatic hernias

• DDx

– Bronchopulmonary foregut malformation

– Sequestration

– Congenital cystic adenomatoid malformation

– Pulmonary agenesis or hypoplasia

Acquired Diaphragmatic Hernias

• Trauma or degeneration

• Hiatal hernia

• Traumatic diaphragmatic rupture

Hiatal hernia

• 50% of diaphragmatic hernia

• Acquired: mostly

• Congenital

Hiatal Hernia

• Esophageal hiatus • Due to stretching,

weakening, or tearing of the phrenoesophageal mb

• Upward dislocation of the esophagus and stomach

• 2 types– Sliding-type– Paraesophageal

Hiatal Hernia

• Incidence increases with age

• Most are asymptomatic

• About 1/5 of patients with a hiatal hernia have associated gastro-esophageal reflux (only in sliding hernia)

Sliding hiatal hernia: Complications

• Best characterized on esophagogram

• Schatzki’s B ring demarcates the GE junction

displaced above the diaphragm


• Large incarcerated hiatal hernias may slowly weep blood

– Iron deficiency anemia

• Peptic esophagitis from reflux

• Discrete marginal ulcers

• Strictures


• Common association with Barrett’s esophagus

– Columnar epithelium lining the esophagus

– Acquired condition related to chronic GERD

• Patients with a Barrett’s esophagus can develop

– Ulcer

– Stricture

– Malignancy

• 30-40 times higher risk of esophageal adenocarcinoma than the general population

Paraesophageal hiatal hernia

• All or part of the stomach enters the thorax through a defect in the phrenoesophagealmembrane

• Alongside the esophagus

• GE junction remains in the peritoneal cavity

• Not associated with GE reflux

• Usually incarcerated

• Higher risk of gastric volvulus

Larger hiatal hernias

• Radiograph: a gastric air bubble above the diaphragm– in the midline on frontal view

– posterior to the heart on lateral view

• CT or MR: gastric folds pass through the hiatus

• EG junction above the diaphragm: sliding

• EG junction under the diaphragm: paraesophageal type

Other conditions

• Intrathoracic stomach

– Cardia may still be subdiaphragmatic

– Greater curvature may be on left or right side

• Congenitally short esophagus (rare)

– Short, straight esophagus

– Stomach in thorax

– GE reflux

Hiatal hernia

• Acquired: mostly

• Congenital

– A delay in the descent of the stomach from the chest

– Children with paraesophageal hernia

• Gastrosplenic and gastrocolic ligaments are often absent in

• Prone to organoaxial volvulus of the stomach and colonic herniation

Traumatic Diaphragmatic Rupture

• Blunt injury

– Trauma

– Pregnancy or labor

– Spontaneously

The defect size is typically greater than 10 cm.

• Penetrating injury

Usually less than 2 cm in length


Lateral impacts

• An AP elongation

• Rupture of the diaphragm or insertion detachment

Frontal impacts

• Increase intra-abdominal pressure abruptly

• Transmitting the impact to the pillars of the diaphragm

• RuptureRib fracture

• Rupture of the diaphragmatic insertion

• Tears are most likely to occur at sites of structural weakness• within the central tendon

• junction of muscle and central tendon.


• Blunt traumatic diaphragmatic rupture is more common on the left side

– The right hemidiaphragm may be relatively protected from injury due to buffering by the liver

– Delayed presentation--more common on the right side, can lead to complications such as bowel strangulation

• Indicative of a high impact and is associated with other severe injuries


Direct signs

• Abrupt loss of diaphragm continuity

• No visualization of the hemidiaphragm

• Dangling diaphragm sign

Indrect signs

• Protrusion of abdominal content into the pleural space

• Collar sign

• Dependent viscera sign

• Hump sign

• Elevated abdominal organs

Direct signs of diaphragmatic rupture


– Associated with a thickening of the free edge due to retraction or hemorrhage

– Spotted when the defect is small or in contact with the abdominal fat or the aerated lung.

– This sign has a sensitivity ranging from 17 to 80%, with a specificity of 90 to 100%.



– Large hernial defects

– This sign has a specificity of 91% and a sensitivity ranging from 18 to 43%



– A comma-shaped curving of the free edge at the rupture site

– This sign has a specificity of 98% and a sensitivity of 54%


Direct signs




Indirect signs

• Protrusion of abdominal content into the pleural space

• Collar sign


• Hump sign


Indirect signs of diaphragmatic rupture

• Protrusion of abdominal organs or peritoneal fat into the pleural space

– This sign has a specificity of 98% and a sensitivity ranging from 50 to 95%


• Collar sign

– Secondary to the compression of a herniated structure at the site of rupture

– DDx diaphragmatic displacement, hepatic lacerations or artifacts caused by breathing



– The herniated abdominal organ in direct contact with the posterior thoracic wall

– Spleen, liver, stomach and intestinal loops suspended above the diaphragm and separated from the posterior thoracic wall by the lung parenchyma.

– Herniated abdominal viscera to slightly drop, due to gravity, into contact with the posterior thoracic wall.

– This sign has a specificity ranging from 54 to 90% and a sensitivity ranging from 98 to 100%.


• Hump sign

– A consequence of hepatic herniation

– hypodense band in the hepatic parenchyma between the torn diaphragm edges

(compression-driven hypoperfusion condition)



– Contralateral hemidiaphragm to be at a lower level

– Suggestive when displacement > 5 cm in the right side and 4 cm in the left side is found

– DDx simple anatomical variation, eventration, paralysis of the diaphragm, or presence of subpulmonary fluid.

Summary

• Anatomic variants

– Diaphragmatic slip

– Nodular crura

– Prominent (hypertrophic) median and lateral arcuate ligaments

Summary

• Diaphragmatic hernias

– Congenital: Bochdalek and Morgagni hernia

– Acquired: Hiatal hernia and traumatic

References

• Chavhan, G. B., P. S. Babyn, R. A. Cohen, and J. C. Langer. "Multimodality Imaging of the Pediatric Diaphragm: Anatomy and Pathologic Conditions." Radiographics 30.7 (2010): 1797-817. Web.

• Taylor, George A., Omolola M. Atalabi, and Judy A. Estroff. "Imaging of Congenital Diaphragmatic Hernias." Pediatric Radiology 39.1 (2009): 1-16. Web.

• Gimena A. R., Jorge A. C., and Liliana A. “Traumatic Diaphragmatic Hernia: Case Series and Topic Review.” Colomb Radiol. 2012; 23(4): 3579-86. Web.

• Desir, Amandine, and Benoît Ghaye. "CT of Blunt Diaphragmatic Rupture." RadioGraphics 32.2 (2012): 477-98. Web.

• "Hiatal Hernia." LearningRadiology, n.d. Web. 29 Mar. 2015.

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