Omentalization in Cats

Omentalization is a procedure performed with the purpose of encouraging tissue to heal. The technique is most frequently used as part of gut surgery, but can be adapted to drain cysts (accumulations of fluid under the skin) and abdominal abscesses. 

The omentum is a fine, fatty infiltrated membrane with a rich blood and lymphatic supply, which is wrapped around the gastrointestinal tract within the abdomen. Often referred to as the abdomen's 'policeman', it has many roles which include mopping up infection, increasing blood supply, and to aid healing. Omentalization involves relocating part of the omentum (whilst retaining its original blood supply) to another part of the body where these functions are made use of to act as a drain or transport in healing cells. 

Omentalization is not technically demanding but it is invasive, because the omental graft is harvested from the abdomen and requires laparotomy to retrieve it. 

Omentalization must be performed under general anesthetic. Both the abdomen and the site for repair must be clipped and disinfected with surgical scrub. The surgeon first makes an incision into the abdomen, identifies the omentum, and creates a pedicle (a long thin strip) of omentum, whilst taking care to preserve its blood supply. 

When the aim is to repair, for example, an wound in the armpit - a tunnel is made under the skin, connecting the area in need of repair to the abdomen. The omental pedicle is fed through the tunnel to emerge at the wound or cyst. The omentum is then fanned out and sutured loosely in place. The skin is closed over the transplanted omentum, and the abdominal wound closed. 

Omentalization is an extremely useful technique which is highly effective at providing continual drainage for cysts or seromas where fluid is constantly produced. When used to drain an internal abscess, once the infection is resolved, the omentum merely stays in place and doesn't need to be resected or removed. 

There are few complications associated with omentalization and these are minor. These can include things such as the omental pedicle dying off. This is usually because too much tension was applied to the graft and the blood supply was damaged. However, this is not serious and the biggest concern is that the procedure was not successful, rather than it being harmful in any way. 

The recovery period is dictated by the amount of time it takes to recover from abdominal surgery. Thus 10 to 14 days is a typical recovery time, which is  also when the skin sutures are removed. The omentalization will work on a permanent basis, provided the blood supply to the pedicle was not damaged or twisted during the initial surgery. 

Prior to suture removal, the cat must not lick at either the wound incision or the recipient bed op site, so this may require wearing a cone. In addition, it is best to restrict the cat from being overly active and jumping, as this could cause swelling of the laparotomy incision. 

The cat may need to take antibiotics and painkillers during the postoperative period. Whilst the omentalization itself is not a painful procedure, surgically opening the abdomen is uncomfortable and pain relief will reduce unnecessary discomfort.

Omentalization must be done under general anesthetic. This may involve pre-anesthetic tests to assess the patient, with screening blood tests ranging from $50 to $150 depending on the panel selected. A basic anesthetic cost is $99 upwards, with additional fees for a lengthy procedure. 

The omentalization is often charged according to the amount of surgical time it takes to perform. Whilst the surgery is not technically demanding, it can take 45 to 120 minutes from start to finish in order to perform a laparotomy, prepare and pass the graft, suture it in place, and then close both sites. This can be done in first opinion practice, although some vets may choose to refer if the procedure is unfamiliar to them. For a vet in general practice, the surgical cost per hour ranges from $70 to $140 upwards, with a specialist surgeon being many times this amount. 

Omentalization is a procedure often reserved for a difficult case in which other solutions have failed but a permanent solution needs to be found. Problems such as a large cyst under the skin which keeps reforming but cannot be surgically excised, could respond well to omentalization. 

The omentum provides a 'drain' to soak away the cystic fluid as it develops, hence keeping things in check. Think of this like a tap dripping into a sink with a blocked outflow pipe - clean the outflow pipe and the sink won't overflow. In this case, the dripping tap is the cystic fluid, the sink is the cyst, and the outflow pipe is the omentum.

When presented with a large cyst or a non-healing wound the clinician will explore simpler options first. Because omentalization is used when other procedures have failed, it is not so much a matter of prevention omentalization, but finding the patient for whom it would be appropriate.