Let’s undo the twist: diagnosing and treating splenic torsion in dogs

Surgical correction of a twisted splenic vascular pedicle.

The serious nature of spleen removal surgery is often overlooked. Perhaps the fact that dogs can function well without the organ is partly to blame. Or maybe, as posited by Harry W. Boothe, DVM, MS, DACVS, professor emeritus of soft-tissue surgery at Auburn University College of Veterinary Medicine, it’s because for many years it wasn’t unusual for veterinary schools to use the procedure in junior surgical laboratory settings as an exercise in knot tying and ligation placement.

Years of experience have taught Boothe to see the surgery a little differently. He says that while splenectomies are often straightforward and predictable, he has been a part of many surgeries that haven’t fit that neat and tidy mold— both peri- and postoperatively. “There are a lot of things we don’t understand about the spleen,” Boothe explained during a session at the Fetch dvm360® virtual conference in August, “not the least of which is the cause of cardiac arrhythmias being associated with splenic masses, splenic enlargement, and splenectomies.”

Close-up surgical image. Note the proximity of the left pancreatic limb to the twisted pedicle.

A lean and mean review of the spleen

Boothe began with a quick refresher on splenic anatomy. The spleen, he said, is suspended by the greater omentum and attached to the greater curvature of the stomach by the gastrosplenic ligament. The splenic artery arises from the celiac artery, which is the first branch of the abdominal aorta and divides into multiple smaller hilar branches before entering the spleen.

“In addition to supplying the spleen, the splenic artery supplies the left pancreatic limb," Boothe said. That pancreatic limb that lies caudal and parallel to the stomach is a lot closer to the spleen than I think we often realize—or at least the blood supply is. And I think part of
my concern with some of the minimal ligation techniques is that, particularly with splenic hilar disease, we could be a lot closer to embarrassing blood supply to the left pancreatic limb then we realize.”

Boothe added that it is important to remember that although the splenic veins parallel the splenic artery, they enter the portal vein, not the caudal vena cava. “We can use them to access the portal venous system and to evaluate portal venous pressures,” he explained.

Plot twist: diagnosing splenic torsion

There are several reasons for removing a patient’s spleen, including lesions and trauma. Boothe focused first on splenic torsion, explaining that the condition occurs when the spleen rotates around its vascular pedicle, resulting in venous obstruction and subsequent splenomegaly.

True to the textbooks, Boothe has seen splenic torsion consistently in large- and giant-breed dogs with deep-chested conformations. “In my experience, it’s usually an isolated event, meaning it’s not necessarily associated with trauma or other situations." But, he said, “we always look for splenic torsion in association with gastric-dilatation volvulus.”

Boothe explained that there are 2 possible presentations for dogs with splenic torsion: acute and chronic. Abdominal pain and collapse are common acute presentations, while vomiting, anorexia, intermittent abdominal pain, abdominal distension, polyuria, and polydipsia characterize chronic cases. “I can recall a case with chronic presentation that did very poorly following splenectomy,” said Boothe. “I think time is some- what of the essence in dealing with presumed or documented splenic torsion.”

With regard to laboratory results, Boothe said hemoglobinuria may be noted on urinalysis in chronically presenting patients and that hematologic findings often include anemia, thrombocytopenia, and leukocytosis.

Ultrasonography is the best imaging tool for diagnosing splenic torsion.

While abdominal radiography and ultrasonography are often part of getting to a diagnosis, Boothe said he could probably argue that you can't definitively diagnose splenic torsion based on radiographs alone. Abdominal ultrasound, however, particularly with Doppler flow capabilities, is an excellent diagnostic tool in splenic torsion cases. "Findings often include generalized splenomegaly, evidence of splenic infarction, a twisted splenic pedicle, and absence of blood flow through the splenic vessels on Doppler evaluation," Boothe explained. Still, he said, it's not uncommon for the definitive diagnosis to be made at the surgery table through exploratory laparotomy.

How to unwind: treating splenic torsion

Complete spleen removal is the treatment of choice for dogs with splenic torsion. Boothe said if you can perform surgery in a timely fashion, you will typically just see splenic engorgement with a twisted pedicle once your patient reaches the operating table. "But if it's been more of a chronic situation with a delay in getting to surgery," he continued, "there may be evidence of venous thrombosis and the possibility of necrosis." Necrosis tends to correspond with worse outcomes, he said.

Because Boothe knows that the patient’s splenic tissue may be friable, making simple attempts at exteriorization potentially insulting to the patient, he approaches the situation with what he calls a somewhat old-school plan that’s become his default. First, he confirms the location of the left pancreatic limb. Then, he uses 1 or 2 large-diameter sutures (eg, #1 polydioxanone) to ligate the entire splenic vascular pedicle before removing the spleen in its twisted state.

With the spleen out, Boothe slowly untwists the pedicle, examines it for hemorrhage, and places additional ligatures or uses a high-energy sealing device as needed. “Now, one could argue that high-energy sealing devices could be used to work through the pedicle in its twisted state and deal with it that way,” he said, “but I think that sometimes it’s easier and quicker to get the spleen out and then deal with the pedicle as a separate structure.”

Because delayed hemorrhage is a possible postoperative complication, Boothe is careful to ensure that the vascular pedicle isn’t bleeding before closing the patient’s abdomen and performing intraoperative peritoneal lavage to evacuate the hemorrhagic effusion.

Don’t miss a beat (particularly the irregular ones)

Remember those mysterious postoperative cardiac arrhythmias associated with splenectomies? Boothe does too, which is why he recommended that splenectomy patients recover for 2 to 3 days after surgery at a 24-hour care facility or in a setting with overnight monitoring—"not necessarily with continuous heart monitoring," he explained, "but just to make sure we’ve got good perfusion, good mentation, and good recovery from the procedure.”