Page 237 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

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BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery
BSA
OPERATIVE TECHNIQUE 17.1
VetBooks.ir Surgery for diaphragmatic rupture

PATIENT PREPARATION AND POSITIONING
The patient is placed in dorsal recumbency with the forelimbs tied cranially. The ventral abdomen is clipped and
prepared for a routine ventral midline laparotomy. The ventral thorax should also be clipped and prepared in case a
caudal sternotomy has to be performed. Although this is a clean or clean-contaminated procedure, perioperative
antibiotics are indicated.

ASSISTANT
It is desirable to have an assistant to help retract the abdominal viscera.

ADDITIONAL INSTRUMENTS
Abdominal retractors, e.g. Balfour or Gossett; a mechanical stapler (in case a liver lobectomy is required); an oscillating
saw if a sternotomy is required; long-handled thoracic instruments may be useful for suturing the dorsal aspect of the
diaphragm in deep-chested animals.

SURGICAL TECHNIQUE
Approach
A standard ventral midline laparotomy is performed with an incision from the xiphisternum to approximately halfway
from the umbilicus to the pubis. This incision may be extended caudally to the pubis if required. A partial or complete
median sternotomy may be required if access is difficult or if there are extensive adhesions.
Surgical manipulations
1 Gentle traction is applied to the viscera to reposition the herniated organs into the abdomen as soon as possible,
to remove the compression on the lung lobes. If this cannot be performed, it may be due to engorgement of the
organs following entrapment, or the formation of adhesions. In this case, the hole in the diaphragm may be
enlarged to allow inspection and reduction of the organs. This is best performed by extending the incision in a
radial direction ventrally, taking care to avoid vital structures such as the phrenic vessels, phrenic nerves and
caudal vena cava.
2 Adhesions to intrathoracic structures should be divided under direct observation if possible. More mature
adhesions may require division of the affected part, e.g. by partial lung lobectomy or complete liver lobectomy.
Incarcerated liver lobes and spleen are often friable and should be handled with care. If these appear devitalized,
lobectomy or splenectomy should be performed, ideally before returning the organs to the abdomen.
3 Once reduced, the abdominal viscera are retracted using saline-soaked laparotomy swabs and malleable ribbon
retractors. Following repositioning of the abdominal viscera, a routine exploration of the entire abdomen is
performed.
4 The thoracic cavity is lavaged with warm saline and a chest drain is placed into the pleural space under direct
visualization before closing the diaphragm.
With an acute diaphragmatic rupture, it is generally simple to determine the correct orientation of the tissues
and rarely is there insufficient tissue to close the defect. In chronic hernias, the edges of the defect may have
rolled over and mature fibrous tissue may have formed, causing contraction of the tissue. It is not recommended
to debride the edges of the hernia, because that will increase the size of the defect further and may reduce the
holding power of the sutures. However, any scar tissue that prevents movement of the diaphragm should be
incised.
The most dorsal suture is placed first and the ends are left long and tagged with a haemostat. Traction on this
haemostat allows the rest of the diaphragm to be elevated into the surgical field and facilitates closure, working
from dorsal to ventral. Care must be taken to avoid constriction of structures running through the diaphragmatic
hiati, e.g. the caudal vena cava, during herniorraphy. In circumcostal tears, it may be difficult to approximate the
diaphragm to the abdominal wall and, in these cases, sutures may be passed around the adjacent ribs or
xiphisternum.
5 Closure of the laparotomy wound is routine. Rarely, in a patient with a chronic hernia, the abdominal organs may
not fit into the abdomen because of loss of abdominal domain. In this case, an elective splenectomy may reduce
the volume of the abdominal viscera.

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