Veterinary Surgery April 2026 – Soft Tissue: HAVM Occlusion, Laparoscopic Warmups & PPDH Repair

In this Simini Small Animal Surgery Podcast episode, we continue our soft tissue coverage from the April 2026 issue of Veterinary Surgery by focusing on how minimally invasive surgery continues to evolve through better technique, better preparation, and smarter intraoperative decision-making. 

From hepatic vascular malformations to laparoscopic performance warmups and thoracoabdominal hernia repair, these studies show how modern surgery increasingly depends on understanding both the patient’s physiology and the surgeon’s performance under pressure.

In this episode:

✅ Weiss et al. — A 20-year retrospective study evaluating treatment strategies for hepatic arteriovenous malformations (HAVMs) in dogs. Medical management alone resulted in zero long-term survivors, while surgery dramatically improved outcomes. Among surgical approaches, dominant outflow vein occlusion (DOV) achieved a 95% acute occlusion rate and only 15% recurrence, significantly outperforming transarterial embolization (TAE), which showed a 53% recurrence rate due to collateral vessel recruitment. The study emphasizes the importance of venous outflow control using nonabsorbable suture ligation over mechanical occlusion devices. 

✅ Foreman et al. — A prospective study investigating whether a simple 30-minute preoperative laparoscopic warmup improves surgical performance in veterinary students performing live dog ovariectomies. Students who completed simulator exercises and laparoscopic video gaming reduced operative time by 20 minutes (63 vs. 84 minutes) and achieved significantly higher performance scores. The findings highlight the role of psychomotor priming and structured warmups in minimally invasive surgery training. 

✅ Massari et al. — The largest reported case series evaluating laparoscopic repair of peritoneopericardial diaphragmatic hernias (PPDH) in dogs and cats. Using ultra-low insufflation pressures (3–4 mmHg) and active pericardial venting, the authors achieved successful minimally invasive repair in 92% of cases. One patient required emergency conversion due to tension pneumopericardium and cardiovascular collapse, reinforcing the importance of careful hemodynamic management during thoracoabdominal laparoscopy. 

Together, these studies demonstrate that successful minimally invasive surgery depends just as much on preparation and physiology as it does on instrumentation.

🎓 Journal Articles Discussed

• Weiss et al. — Procedural descriptions and survival times for hepatic arteriovenous malformations (HAVM) in animals receiving primarily conservative treatment, arterial embolization, or dominant outflow vein occlusion
• Foreman et al. — Effects of preoperative warm-ups on veterinary medical students' performance with live dog laparoscopic ovariectomy
• Massari et al. — Laparoscopic repair of peritoneopericardial hernias: Multicentric retrospective case series of 12 dogs and one cat

📚 From the April 2026 issue of Veterinary Surgery

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Transcript

SPEAKER_01 0:04

Hi, I'm Carl Di Miani, and this is the Simene Small Animal Surgery Podcast, your fast, focused update on what matters most from the latest small animal surgical literature. In each episode, we break down key articles from the veterinary journals and translate them into surgical insight you can use. Today, not someday. This episode continues our soft tissue coverage from the April 2026 issue of veterinary surgery, and this time the focus is minimally invasive surgery, surgical performance and pushing laparoscopy into increasingly complex territory. First, we'll review Weissa et al. exploring advanced minimally invasive techniques and what they mean for modern soft tissue practice. The paper tackles the practical realities of expanding laparoscopic capability from technical decision making to intraoperative problem solving and highlights how surgical innovation continues to reshape case management. Next, we turn to Foreman et al. who investigated whether a simple preoperative warmup could improve laparoscopic performance in veterinary students performing live dog ovarectomies. Using simulators and even laparoscopic video gaming, the authors found measurable improvements in surgical efficiency and operative scoring. It's a fascinating look at surgical training, psychomotor preparation, and how we develop technical consistency in the next generation of surgeons. Finally, Masari et al. present the largest reported case series on laparoscopic repair of peritoneo-pericardial diaphragmatic hernias in dogs and cats. Using low pressure insufflation techniques, the authors achieved successful minimally invasive repair in the vast majority of cases while carefully managing the cardiovascular risks unique to these patients. It's an important paper for anyone interested in advanced thoracoabdominal laparoscopy and minimally invasive hernia repair. Three studies, one shared theme. Minimally invasive surgery isn't just evolving through better equipment. It's evolving through better preparation, better technique, and a deeper understanding of how surgeons perform under pressure. Let's dive in.

SPEAKER_00 2:27

Welcome to today's clinical deep dive, where we are grabbing some actionable surgical intelligence for the OR.

SPEAKER_03 2:33

Yeah, and today we are looking at a really tricky vascular anomaly.

SPEAKER_00 2:38

Oh, definitely. I mean, imagine a massive plumbing nightmare, right? Like you've got high pressure arterial water completely bypassing the filter, which is your patient's liver, and it's just blasting directly into the low pressure drain of the portal vein.

SPEAKER_03 2:52

Aaron Powell Right. It's just sheer physical chaos.

SPEAKER_00 2:54

Aaron Ross Powell Exactly. And that is exactly what you face with a hepatic arteriovenous malformation or HAVM in a dog.

SPEAKER_03 3:01

Yeah. And that high flow anomaly, it causes massive portal hypertension. Plus, you know, severe liver dysfunction.

SPEAKER_00 3:09

Trevor Burrus And historically this was a nightmare to fix, right? Like hepatic lobectomies carried brutal morbidity rates.

SPEAKER_03 3:14

Oh, absolute brutal mortality and morbidity. But today we are diving into a 20-year retrospective study by Weiss et al. from 2026. Trevor Burrus, Jr.

SPEAKER_00 3:23

Right. The one comparing conservative medical management against two minimally invasive surgery.

SPEAKER_03 3:28

Exactly. They looked at transarterial glue embolization, which we'll call TAE, and dominant outflow vein occlusion, or DOV.

SPEAKER_00 3:36

Aaron Powell Well, just looking at the baseline data, uh medical management alone is just a dead end for these patients.

SPEAKER_03 3:41

Yeah, totally.

SPEAKER_00 3:42

I mean the median survival time is only 567 days, zero long-term survivors. So surgery is absolutely mandatory here.

SPEAKER_03 3:50

It is. And when you look at those two surgical options, um DOV is the definitive winner for durability. Aaron Powell Okay.

SPEAKER_00 3:57

Break that down for us a bit.

SPEAKER_03 3:58

Sure. So TA tries to block the arterial feed, right? While DOV blocks the venous exit to like force a clot.

SPEAKER_00 4:07

And both improve survival, theoretically?

SPEAKER_03 4:09

They do. But DOV achieved a 95% acute complete occlusion rate. TAE was sitting at just 56%.

SPEAKER_00 4:16

Aaron Ross Powell Wait, I mean that doesn't make total sense to me. If TE blocks the primary arterial feed with glue, you've basically cut off the water supply, right?

SPEAKER_03 4:24

You would think so, yeah.

SPEAKER_00 4:25

So how is TE showing a massive 53% recurrence rate while DOV's recurrence is only 15%? Like where is that blood even coming from if the arteries glued shut?

SPEAKER_03 4:34

Well, HAVMs are incredibly sneaky.

SPEAKER_00 4:36

Really? How so?

SPEAKER_03 4:38

When you glue that primary hepatic arterial feed, the malformation simply recruits secondary blood supply from non-hepatic arteries.

SPEAKER_00 4:46

Oh wow. Like which ones?

SPEAKER_03 4:48

Like the gastric or the phrenic arteries, you know. They just completely bypass your glue and keep that high pressure flow going.

SPEAKER_00 4:55

That is wild.

SPEAKER_03 4:56

Yeah. So DOV works so much better because it attacks the single outflow bottleneck. By occluding the exit drain, you trap the blood and force the entire malformation to thrombose.

SPEAKER_00 5:07

Right, because it doesn't matter how many collateral arterial feeders try to supply it if the exit is blocked.

SPEAKER_03 5:12

Exactly.

SPEAKER_00 5:13

So okay, if you're scrubbing in tomorrow, the main takeaway is you want to do DOV. But study highlighted some uh really critical procedural nuances too.

SPEAKER_03 5:22

Oh, absolutely. The mechanical reasoning here is crucial.

SPEAKER_00 5:24

Right, because you cannot use surgical staplers or mechanical plugs or coils to occlude that vein.

SPEAKER_03 5:30

No, definitely not. I mean, think about the pressure gradient. That arterial flow blasting into that vein creates just immense turbulent pressure.

SPEAKER_00 5:38

Yeah, it's a thin-walled vein, right?

SPEAKER_03 5:40

Aaron Ross Powell, Exactly. Surgical staplers or standard plugs, they simply can't hold a seal against that kind of pounding force.

SPEAKER_00 5:47

Aaron Powell And the data showed that, right? Those mechanical closures were directly associated with fatal postoperative hemorrhage.

SPEAKER_03 5:52

Aaron Powell Yeah, or a persistent blood flow just blowing right past the blockage.

SPEAKER_00 5:55

Aaron Powell So you have to use non-absorbable encircling sutures instead.

SPEAKER_03 5:59

Aaron Powell Yes, non-absorbable is key.

SPEAKER_00 6:01

Aaron Powell And specifically avoid silk, right? I read they documented a case where the natural absorption of the silk suture caused the malformation to recur.

SPEAKER_03 6:11

Aaron Powell Yeah, the tension just failed over time.

SPEAKER_00 6:13

Yeah.

SPEAKER_03 6:13

Getting that closure technique right radically changes the outcome. I mean, 78% of dog owners in the DOV group reported an excellent post-op quality of life.

SPEAKER_00 6:22

Wow, 78%. And the TAE group.

SPEAKER_03 6:25

Only 27%.

SPEAKER_00 6:26

Aaron Ross Powell That is a massive difference. So basically skip the medical management alone, skip the TAE, and prioritize DOV occlusion using non-absorbable sutures.

SPEAKER_03 6:35

Exactly. Lowest recurrence, highest quality of life.

SPEAKER_00 6:37

Now, uh, while we are talking about reinforcing surgical success and avoiding complications, there is an important update for your orthopedic protocols.

SPEAKER_03 6:45

Aaron Powell Oh, yeah, this is a good one.

SPEAKER_00 6:46

Right. Most surgeons use standard saline to rinse before closure, but studies show saline actually leaves 42% of bacteria behind in the site.

SPEAKER_03 6:56

Aaron Powell, which is a huge blind spot.

SPEAKER_00 6:58

Yeah, it really is. So Simedy Protect Livage is a non-antibiotic lavage that removes what saline misses. It leaves 0% behind in head-to-head studies.

SPEAKER_03 7:08

Aaron Powell And it only takes what, like 60 seconds?

SPEAKER_00 7:10

Exactly. 60 seconds. Doesn't alter your workflow at all. But keep in mind it's specifically designed for orthopedic primary and revision surgeries. Aaron Powell Right.

SPEAKER_03 7:18

So meaning you do not use this for the abdominal HAVM procedures we just broke down.

SPEAKER_00 7:22

Aaron Ross Powell Exactly, completely different application. But it's a great targeted clinical upgrade for ortho.

SPEAKER_03 7:28

Definitely.

SPEAKER_00 7:29

So to wrap up our vascular plumbing problem today, uh I want to leave you with this thought.

SPEAKER_03 7:34

Let's hear it.

SPEAKER_00 7:35

Well, if we are discovering that occluding the outflow drain works drastically better than chasing arterial feeders in the liver, where else in veterinary vascular surgery might we be attacking the wrong side of the pressure gradient?

SPEAKER_02 7:52

Let's explore another relevant study.

SPEAKER_00 7:59

So to start us off, you know, if you watch a baseball pitcher before they step onto the mound, they never just grab the ball and start throwing 90 mile-an-hour fastballs cold.

SPEAKER_03 8:08

Right, definitely not.

SPEAKER_00 8:10

They stretch, they throw practice pitches, they physically and well, mentally prep.

SPEAKER_03 8:16

Yeah, they really have to wake up that mind-muscle connection before the stakes get high.

SPEAKER_00 8:20

Exactly. But then you look at a veterinary OR, you're about to perform a minimally invasive procedure, say a laparoscopic ovarectomy or a love procedure. The cognitive demand is just huge.

SPEAKER_03 8:32

Oh, for sure. The learning curve is incredibly steep. Trevor Burrus, Jr.

SPEAKER_00 8:35

Right. And yet surgeons often just scrub up and start operating totally cold.

SPEAKER_03 8:39

Yeah, that steep learning curve for laparoscopy is a very real challenge you face in the clinic when you know transitioning from traditional open surgery. But a new paper from Foreman et al. 2026 suggests veterinary surgeons might be missing a massive opportunity by skipping that physical prep.

SPEAKER_00 8:56

And that is exactly the mission of today's deep dive to pull out actionable clinical intelligence from this article that you can use in your clinic tomorrow. So how did they actually test this warm-up idea?

SPEAKER_03 9:07

Aaron Powell Well, they took 15 fourth-year veterinary students who only had like basic laparoscopy training, and they split them into two groups right before performing a live dog love eel.

SPEAKER_00 9:18

Okay, so jumping right into the deep end.

SPEAKER_03 9:20

Literally. One group walked in cold while the other did a 30-minute preoperative warmup. And the difference wasn't just minor. I mean, we're talking about a 20-minute reduction in surgical time for the students who warmed up.

SPEAKER_00 9:30

Wait, really? 20 minutes? That is huge. I am still kind of stuck on the actual warmup routine, though.

SPEAKER_03 9:35

How so?

SPEAKER_00 9:36

Because when I hear warm-up for surgery, I picture running through standard surgical knots or like basic suturing drills.

SPEAKER_03 9:44

Sure, the traditional benchtop stuff.

SPEAKER_00 9:46

Right. But this study says they spent 15 minutes on a laparoscopic simulator. And then, and this is the crazy part, 15 minutes playing a Nintendo video game called underground. I mean, come on. How does mashing buttons on a controller actually prepare your hands for living tissue?

SPEAKER_03 10:04

It sounds like a gimmick, I know. But it really comes down to psycho motor priming. Minimally invasive surgery requires this very specific hand-eye coordination.

SPEAKER_00 10:14

Because you're looking at a monitor, right?

SPEAKER_03 10:16

Exactly. You are translating a two-dimensional screen image into three-dimensional movements. Plus, you're dealing with the fulcrum effect, where your hands move opposite to the instruments inside the patient.

SPEAKER_00 10:26

Oh wow, right. Because of the pivot point at the port?

SPEAKER_03 10:29

Precisely. So the video game and the simulator, they basically forced the brain to boot up those complex spatial and motor pathways.

SPEAKER_00 10:36

So you're getting the mental gears turning before ever picking up a scalpel. And the results are, well, they're undeniable. A 20-minute reduction is a massive drop in time under anesthesia for the patient.

SPEAKER_03 10:45

Aaron Powell Yeah, let me give you the specific numbers. The warmup group averaged 63 minutes of surgical time compared to 84 minutes for the cold group.

SPEAKER_00 10:54

That is a staggering difference for novices.

SPEAKER_03 10:56

It is. And they didn't just move faster, they actually scored significantly higher on a validated performance rubric, averaging 138.4 out of 160 versus just 121.5 for the cold group.

SPEAKER_00 11:08

Aaron Powell So they were faster, but they were also safer, they were more efficient without sacrificing technique. Exactly. But uh there is a procedural discrepancy in the study that really stands out to me. The synthetic tissues in their simulator weren't compatible with vessel ceiling devices.

SPEAKER_03 11:24

Yeah, that is a really interesting nuance.

SPEAKER_00 11:26

So the students just used standard laparoscopic scissors during the warmup, right? But then they turned around and used a vessel ceiling device on the live dogs. Aren't they practicing with the wrong tool?

SPEAKER_03 11:36

You would think that would be a problem, but that's actually the beauty of the finding. The specific instrument changed, but the spatial and motor skills still seamlessly transferred to the live procedure.

SPEAKER_00 11:47

Oh, so the underlying movements are what count.

SPEAKER_03 11:49

Right. The psychomotor readiness is what matters, not just mimicking the exact tool you'll use in the OR. The foundational mechanics were primed.

SPEAKER_00 11:58

That really reframes how we look at prep time. I mean, if you are teaching a resident or taking on a tough laparoscopic case yourself, a quick bench top or video game warmup isn't a distraction, it's an efficiency tool.

SPEAKER_03 12:11

It's a very low-cost intervention for a high value returned in patient safety. It significantly cuts down on surgical stress for the operator, all while keeping the patient off the table longer than necessary.

SPEAKER_00 12:23

Which leaves me with a final thought for you to ponder. If a simple 30-minute video game session can shave 20 minutes off a novice's surgical time, how could a customized virtual reality warm-up routine optimize the workflow and precision of an already experienced surgeon?

SPEAKER_03 12:38

That is a great question and definitely the future of surgical training.

SPEAKER_00 12:41

It really is. Well, a reminder that you can find the full link to the article in the show notes. Next time you prep for the OR, maybe treat it a bit more like stepping onto the pitcher's mound. Get that warm-up in.

SPEAKER_02 12:56

Here's the next article.

SPEAKER_00 13:02

Imagine you are performing a laparoscopic procedure, right? But like the second you insufflate the abdomen, your patient's heart rate just absolutely plummets.

SPEAKER_03 13:12

Yeah, that is a terrifying scenario.

SPEAKER_00 13:13

Right. Yepnograph drops, venous return tanks, and you are suddenly staring down an acute cardiac crisis. Well, today we are looking at how to prevent that exact nightmare. We are looking at Masari et al. 2026, which explores a minimally invasive approach to fixing peritoneo-paricardial diaphragmatic hernias or PPDH.

SPEAKER_03 13:36

Aaron Powell Yeah, it is such a vital technique to master for the OR tomorrow.

SPEAKER_00 13:40

Yeah.

SPEAKER_03 13:40

Especially since we find this defect incidentally on imaging so often, particularly in high-risk breeds like Wimaraners and Maine Coons.

SPEAKER_00 13:47

Definitely.

SPEAKER_03 13:48

And historically, you know, fixing this meant a highly invasive open approach. But Masari et al. evaluated moving to laparoscopy in a retrospective cohort of 13 patients, so 12 dogs and one cat, just to minimize that tissue trauma.

SPEAKER_00 14:00

Okay, let's unpack this though, because the immediate red flag for any surgeon listening is the pneumoparitonium.

SPEAKER_03 14:05

Oh, absolutely.

SPEAKER_00 14:05

Right. When you insufflate an abdomen with a PPDH, that CO2 treks directly through the diaphragmatic defect and straight into the pericardial sac.

SPEAKER_03 14:14

Which is exactly the problem. You aren't just inflating the belly, you are creating an iatrogenic tension pneumopericardium.

SPEAKER_00 14:21

Yeah, you are compressing the right atrium and just wrecking cardiac output.

SPEAKER_03 14:26

Right. And that is exactly why this procedure requires strict technical modifications. I mean, the data is really encouraging. They had a 92% success rate with 12 out of 13 patients repaired entirely laparoscopically.

SPEAKER_00 14:39

But wait, what about that one conversion to open surgery? I mean, what went wrong there?

SPEAKER_03 14:43

Aaron Powell Well, what's fascinating here is that the single conversion was caused by that exact hemodynamic crash you just described. The CO2 pressure exceeded venous pressure.

SPEAKER_00 14:52

Wow. So it triggered severe pericardial tamponade.

SPEAKER_03 14:55

Yeah, tamponade and bradycardia. They had to open the chest immediately to save the patient.

SPEAKER_00 14:58

Okay, so for the surgeons listening, how do you actually keep your patients stable on the table?

SPEAKER_03 15:03

It really comes down to hypermanaging your insufflation. Masari et al.

SPEAKER_00 15:07

Mm-hmm.

SPEAKER_03 15:08

Emphasize using ultra low pressures.

SPEAKER_00 15:10

Like how low are we talking?

SPEAKER_03 15:12

You have to lock your insufflater between three and four millimeters of mercury, and you absolutely never exceed eight.

SPEAKER_00 15:18

Three to four millimeters. I mean, that is barely any working space.

SPEAKER_03 15:21

It is super tight, but low pressure alone still leaves you vulnerable. You know, you have to actively vent the pericardium while you work.

SPEAKER_00 15:30

Right. The authors mentioned placing an 18-gauge catheter or like a millow drain.

SPEAKER_03 15:35

Exactly. Directly into the pericardial space. It gives the track CO2 a continuous escape route, so you are purposefully venting the very space you are trying to suture closed.

SPEAKER_00 15:46

That is brilliant. It prevents the tamponade from developing in the first place.

SPEAKER_03 15:50

Yeah, it's totally essential.

SPEAKER_00 15:51

But going back to that three millimeters of mercury, closing a defect intracorporeally in a field that tight is incredibly unforgiving. How do you decide who is actually a candidate for this?

SPEAKER_03 16:02

Well, the authors introduced a new tool for that triage process, the PPDH-SDC, or surgical difficulty classification.

SPEAKER_00 16:10

Okay, how does that work?

SPEAKER_03 16:11

It breaks cases down into grades to help you determine who actually belongs on the scope. Grades A through C involve simple to moderate adhesions, where you can uh gently mobilize the liver or falsiform fat laparoscopically.

SPEAKER_00 16:25

Aaron Ross Powell Meaning your grade D and E cases like the incarcerated or critical organs, those are strictly open chest procedures, right?

SPEAKER_03 16:32

Trevor Burrus Correct. You cannot safely reduce compromised tissue through a tight defect without wide exposure.

SPEAKER_00 16:38

Yeah, that makes total sense. You need the visibility.

SPEAKER_03 16:40

Exactly. But for those stable lower grade candidates, working in that restricted three millimeter space demands extreme efficiency. The study highlights that using barbed sutures like stratifics or VLOC through a three-port setup is an absolute game changer.

SPEAKER_00 16:56

Oh, to avoid complex not tying intracorporeally.

SPEAKER_03 17:00

Yes, it makes closing the defects so much faster before hemodynamics can destabilize.

SPEAKER_00 17:05

Right. So the clinical bottom line here is that laparoscopic PPDH repair is a fantastic low morbidity option, provided you maintain that ultra-low insuflation and actively vent the pericardium.

SPEAKER_03 17:15

It really is a massive leap forward for patient recovery. But you know, the paper also leaves us looking at the horizon of veterinary surgery.

SPEAKER_00 17:23

Oh, what do you mean?

SPEAKER_03 17:24

Well, as mechanical gasless laparoscopy devices continue to evolve, we might soon bypass insufflation entirely.

SPEAKER_00 17:31

Wait, really? Just mechanically lifting the abdominal wall.

SPEAKER_03 17:35

Yeah. By creating our working space mechanically, we could eliminate the risk of CO2-induced tension pneumopericardium once and for all.

SPEAKER_00 17:43

Completely removing the gas from the equation to solve the hemodynamic challenge. That is a fascinating surgical evolution to keep an eye on. You can find the full link to Masari et al. 2026 in the show notes. Thanks for joining us for this deep dive, and we will catch you next time.

SPEAKER_02 18:02

That's it for this episode of the Simony Small Animal Surgery Podcast. This show is brought to you by Simony Protect Livage, our interoperative lavage developed to target resistant bacteria and biofilms where traditional solutions of saline and post op antibiotics fall short. If you're interested in learning more or trying out your own procedures, you'll find information and links in the show notes. For listening, and we'll see you in the next episode.