Diaphragmatic hernias Flashcards
According to Morgan 2020 in Vet Surg, what were 3 factors likely to result in surgical rather than conservative management of PPDH? What was the recurrence rate after surgical treatment?
Younger patient, sexually intact, clinical signs from PPDH and other congenital abnormalities.
Recurrence rate was 0%.
41% complication rate, most low grade.
Long MST for both conservatively and surgically treated patients.
In a study by Mayhew 2021 in Vet Surg did laparoscopic treatment for sliding hiatal hernia result in improvements in gastroesophageal reflux and hiatal hernia post-operative?
Yes, improvements in severity of GER and SHH were observed (no improvement in frequency).
Decreased regurgitation was also noted by owners based on CDAT questionnaire.
In a study by Mayhew 2023 in Vet Surg, did BOAS surgery result in an improvement in owner perceived regurgitation? Did the same apply for videofluorscopic studies?
Following BOAS surgery owners perceived an improvement in regurgitation after eating and during increased activity/exercise.
On blinded videofluoroscopic assessment there was no improvement in GER or SHH frequency or severity.
Label the following image from Hosgood 2021 in JAVMA describing circumferential hiatal rim reconstruction combined with esophagopexy for treatment of hiatal hernia.
In a study by Singh 2024 in JAVMA, what was the rate of pneumothorax in patients undergoing laparoscopic correction of sliding hiatal hernia?
56% (conversion to open in 22% of dogs).
Dogs owners perceived an improvement in regurgitation after eating and excitement post-op.
In a study by Seibert 2021 in JAVMA, what histopathologic condition was strongly associated with the presence of a congenital PPDH in dogs and cats?
Ductal malformations. These can impact the liver or the kidneys and can affect long term function. Liver biopsies should be performed in instances of PPDH.
Which breed might be predisposed to congenital pleuroperitoneal diaphragmatic hernia?
King charles spaniels. Normally in the left crus of the diaphragm and can cause tension gastrothorax.
In a study by Vangrinsven 2021 in JSAP, treatment of brachycephalic patients undergoing BOAS with antiacids improved what two measures post-operative?
Clinical digestive scores (measure of abnormal GI signs), and presence of gastroesophageal abnormalities (sliding hiatal hernia) during an obstruction maneouvre.
Describe the anatomy of the canine diaphragm.
What are the three major openings of the diaphragm, and what structures pass through each of them?
Caval foramen: Caudal vena cava
Esophageal hiatus: Esophagus, dorsal and ventral vagal trunks.
Aortic hiatus: Aorta, azygous, hemiazygous, lumber cistern of the thoracic duct.
The minor foramina of Morgagni are located ventrally between the sternal and costal attachments of the diaphragm, and allow for passage of the cranial epigastric arteries.
The splanchnic nerves and sympathetic trunk pass into the abdomen lateral to the crura.
What are the diaphragmatic crura?
Paired lumbar muscles that originate from the third and fourth lumbar vertebrae.
What is the name of the pleural reflection that covers the accessory lung lobe?
Plica vena cava
From which cervical nerves do the phrenic nerves arise?
C5, 6, and 7.
In cats derived from C4, 5 and 6.
What is the blood supply to the diaphragm?
Main phrenic arteries which arise from the paired phrenicoabdominal arteries and anastomose with the intercostal arteries.
Phrenic veins (cranial drains to the vena cava, caudal drain to the phrenicoabdominal).
What are some surgical approaches for repair of diaphragmatic herniation?
Ventral midline celiotomy +/- median sternotomy, ninth lateral thoracotomy (need to know the hernia side, cannot be used in cases of PPDH).
What is the proposed mechanism of injury to the diaphragm with blunt trauma?
If trauma occurs when the glottis is open there is a rapid increase in intraabdominal pressure and a sharp change to the peritoneal to pleural gradient, this results in rupture and herniation.
Are male or female dogs at greater risk for diaphragmatic herniation?
Male dogs (1-3 years of age). Trauma is the most common cause (85% of cases).
What is the typical orientation of diaphragmatic tears in dogs?
Circumferential (40%), radial (40%), combination (20%).
In cats circumferential is more common (59%) v. radial (18%).
What organ is herniated most frequently?
The liver, followed by the SI, stomach, spleen, omentum, pancreas, colon, cecum and uterus.
Can depend on the side of herniation (liver, SI and pancreas more common on the right, stomach, spleen and SI more common on the left).
What percentage of dogs with liver herniation develop hydrothorax and ascites?
30% - caused by obstruction/kinking of the caudal vena cava and hepatic veins resulting in liver congestion and production of serosanginous transudate.
Why can incarceration of the stomach in a diaphragmatic hernia be rapidly fatal?
Tympany can result in compression of the caudal vena cava.
What are some potential sequelae of diaphragmatic herniation?
Dyspnea, atelectasis, pain (chest wall contusion, rib fractures, flail chest), hypoventilation, hypoxia, VQ mismatch, shock.
Patients may be on the edge of decompensation and should be handled carefully.
What are the most common signs associated with diaphragmatic herniation?
Dyspnoea and exercise intolerance (38%).
What radiographic projection is the most useful for diagnosis of diaphragmatic herniation?
Lateral projection most useful. Partial loss of the line of diaphragm present in 66-97% of animals. May also see intrathoracic viscera, obscured cardiac shadow.
On the DV view may see lung lobe collapse and pleural fluid (20-31% of cases).
