Page 226 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Chapter 17 · Surgery of the diaphragm

• Prevention of complications arising from chronic to 30 days of medical therapy, or which show frequent
oesophagitis, e.g. stricture relapses following cessation of therapy, or if the owners
VetBooks.ir • Prevention of complications arising from herniation of regime (Bright et al., 1990; Lorinson and Bright, 1998).
are unable to comply with the relatively intensive medical
• Prevention of complications arising from regurgitation,
e.g. aspiration pneumonia
Various surgical techniques have been described in the
human and veterinary literature, and fall into the following
abdominal organs, e.g. gastric tympany.
categories:
It is apparent that surgical or medical therapy alone is
unlikely to achieve all of these aims, and both medical and • Sphincter-enhancing techniques
surgical management are likely to be appropriate in most • Closure of the hiatus
individuals. It is suggested that medical therapy is insti- • Fixation of the stomach and oesophagus.
tuted in all animals (Bright et al., 1990; Lorinson and Bright,
1998). A decision regarding surgical management is then The surgical principles behind surgical management of
taken depending on the success of medical therapy. An any hernia include closure of the hernia ring and fixation
initial period of medical therapy is also indicated in animals of the herniated contents, and therefore techniques that
destined for surgical management, to reduce the signs achieve these aims are likely to yield success. In humans,
associated with reflux oesophagitis and to allow treatment closure of the hiatus and gastropexy (Hill technique) are
for aspiration pneumonia. usually combined with a sphincter-enhancing procedure,
and long-term follow up reveals success rates of 80–95%.
Medical therapy: This consists of: In small animals, sphincter-enhancing techniques are
associated with unacceptable intraoperative and post-
• Establishing a diffusion barrier to peptic mucosal operative complications and are no longer recommended.
damage, e.g. sucralfate
• Improving the tone of the caudal oesophageal Surgical technique: The abdominal portion of the oesoph-
sphincter, e.g. metoclopramide agus and the gastro-oesophageal junction are exposed at
• Neutralizing or suppressing gastric acid secretion, e.g. a cranioventral midline laparotomy. The gastrohepatic liga-
antacids, H2-blockers, proton pump inhibitors ment, part of the lesser omentum, is incised and the left
• Decreasing gastric emptying time, e.g. lobes of the liver are retracted medially. If the stomach is
metoclopramide, liquid meals, low-fat diet herniated, it is reduced by caudal retraction. The abdom-
• Negating the effect of reduced oesophageal tone, e.g. inal portion of the oesophagus is further exposed by
feeding from a height, feeding moist food making a circumferential incision in the phrenico-oesopha-
• Removal of predisposing causes, e.g. weight loss if geal ligament (Figure 17.8), representing the ventral 180
obese, treatment of respiratory disease. degrees (Prymak et al., 1989) or the full 360 degrees
(White, 1993) of the circumference, taking care to avoid the
In early reports, medical therapy was regarded as ventral vagal trunk. The caudal 2–3 cm of the oesophagus
unsuccessful (Gaskell et al., 1974; Ellison et al., 1987; is retracted into the abdomen and the gastro-oesophageal
Prymak et al., 1989), whereas more recent reports con- sphincter is exposed. Placement of an orogastric tube will
clude that medical therapy may be successful in a propor- facilitate identification of the oesophagus.
tion of cases (Bright et al., 1990; Stickle et al., 1992;
Lorinson and Bright, 1998). One of the reasons for this is • Sphincter-enhancing techniques: In humans, there is
that medical therapy is primarily aimed at reducing the a relatively high prevalence of incompetence of the
clinical signs associated with reflux oesophagitis. caudal oesophageal sphincter. Hence, surgical
However, this may not be the main cause of the clinical techniques, such as fundoplication, have been
signs in all animals (Prymak et al., 1989; Callan et al., 1993). designed to augment this region (Merdan Dhein et al.,
Although medical therapy may be successful, it does not 1980; Miles et al., 1988). However, there is no evidence
completely prevent herniation or gastro-oesophageal reflux, to suggest that this occurs in the dog, and these
and long-term complications are possible. These include: techniques do not have a rational basis in this species.

• Aspiration pneumonia from chronic regurgitation
• Oesophageal stricture from chronic oesophagitis
• Chronic low-grade or massive acute haemorrhage from
oesophageal ulceration
• Massive herniation of organs from persistence or
enlargement of a hernia.
Surgical therapy: The indications for surgery are more
poorly defined in small animals. In humans, surgery is indi-
cated if:

• Persistent gastro-oesophageal reflux is unresponsive
to medical therapy
• Oesophagitis develops
• Aspiration pneumonia occurs
• A large hernia which interferes with cardiorespiratory
function is present.

It is likely that similar criteria will apply to small animals. Hiatal hernia: following reduction of the stomach, the
Surgery is recommended for animals that do not respond 17.8 phrenico-oesophageal ligament is incised.

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