A Dog Lover‘s Guide to Pigeon Chest and Other Canine Chest Bone Deformities

As a dog lover, there‘s nothing more important than ensuring your faithful companion lives the healthiest, happiest life possible. So if your precious pup has been diagnosed with a chest bone abnormality like pectus excavatum (PE) or pectus carinatum (PC), it‘s natural to feel worried and overwhelmed. But take heart – with the right care and management, many dogs with these conditions can still lead full, joyful lives. And by educating yourself, you‘re already taking the first step toward being the best advocate for your furry friend.

In this comprehensive guide, we‘ll delve into everything you need to know about chest bone deformities in dogs as both a caring owner and an informed medical partner. We‘ll explore the science behind these conditions, dispel common misconceptions, and arm you with the knowledge to make confident decisions about your dog‘s care. Because at the end of the day, no one knows your dog‘s needs better than you do.

What Exactly Are Pectus Excavatum and Pectus Carinatum?

Pectus excavatum and pectus carinatum are the two most common congenital deformities of the sternum (breastbone) and rib cage in dogs. In basic terms:

• Pectus Excavatum: Latin for "hollowed chest," PE causes the sternum and rib cartilage to grow abnormally and cave inward. The chest appears concave or sunken.

• Pectus Carinatum: From the Latin for "chest like a keel," PC causes the sternum to protrude outward, creating a rounded, bowed-out chest that resembles a pigeon‘s breast.

But there‘s much more to these conditions than cosmetic quirks. Both PE and PC stem from fundamental errors in how the sternum and ribs form during fetal development. Normally, the sternum develops in the midline of the chest and fuses with the costal cartilages of the first eight ribs to create a strong, yet flexible, thoracic cage that protects the heart and lungs.

In puppies with PE and PC, a glitch in this process leads to an abnormal curvature of the sternum and rib cartilage. With PE, overgrowth of the rib cartilage relative to the sternum causes the chest wall to buckle inward along the midline. In PC, it‘s believed that overgrowth of the sternum relative to the ribs forces the chest to balloon outward.

How Common Are Chest Bone Deformities in Dogs?

While PE and PC are the most common chest wall anomalies seen in dogs, they are still considered relatively rare in the grand scheme of canine congenital diseases. Estimating an exact prevalence is tricky, as many mild cases likely go undiagnosed.

Based on the available literature, pectus excavatum is reported to occur in roughly 0.1-0.3% of live dog births. One study of neonatal mortality in puppies found PE in 0.2% of deceased pups examined. However, the true prevalence may be higher when accounting for mildly affected dogs that don‘t show overt symptoms.

Data on the prevalence of pectus carinatum is even more limited, but it seems to be diagnosed slightly less often than pectus excavatum overall. One case study in the scientific literature reported an incidence of 0.05% for PC, but this is likely an underestimate.

Where these deformities are overrepresented is within certain breeds and families of dogs. Researchers have found significantly higher rates of PE and PC in breeds like:

Data adapted from Kurosawa et al. 2022

This breed predilection strongly suggests a hereditary component to these defects. Let‘s take a closer look at the genetic factors at play.

The Genetic Basis of Chest Bone Deformities

While the exact genetic culprits remain elusive, studies in both dogs and humans support that PE and PC have a strong hereditary basis. Breeding experiments dating back to the 1980s demonstrated that these defects can be reliably passed from affected parents to their offspring, especially when breeding two affected dogs.

A landmark 2022 study by Kurosawa et al. investigated the genetic underpinnings in a colony of Whippets bred to express pectus deformities. Through complex segregation analysis, they found that PE and PC are likely polygenic threshold traits with incomplete penetrance. In plain English, this means:

• Multiple genes contribute to the conditions rather than a single gene
• The defects only emerge when an animal inherits a certain threshold number of risk genes
• Not all genetically at-risk dogs will develop a deformity (incomplete penetrance)

This model explains why not all pups born to affected parents will have PE or PC and why severity can vary widely even within a litter. It‘s likely that a "perfect storm" of genetic and environmental factors in utero tips the scale toward improper cartilage and bone growth in the developing fetus.

Researchers believe that unmasking the precise genes involved could pave the way for genetic screening tests to help breeders identify carriers and make informed mating decisions. For now, the recommendation remains to avoid breeding any dog with signs of PE or PC.

Diagnosing Pigeon Chest and Chest Bone Deformities

If you have any inkling that your pup‘s chest looks or feels abnormal, it‘s important to get them checked out by a veterinarian right away. Catching issues early in a growing pup gives you the best shot at preventing complications down the road.

At the vet‘s office, be prepared for a thorough snout-to-tail physical exam with extra attention paid to the chest area. Your vet will carefully feel your dog‘s sternum and rib cage to assess the bony alignment. They‘ll also put a stethoscope to your dog‘s chest to listen for any abnormal heart or lung sounds that could signal reduced chest capacity.

From there, your vet will likely recommend imaging tests to visualize your dog‘s chest structure in greater detail. X-rays are typically the first line of defense, as they can clearly show the extent and positioning of the sternal deformity. More advanced cross-sectional imaging like computed tomography (CT) scans or magnetic resonance imaging (MRI) may be ordered in complex cases.

On imaging tests, the hallmark finding in pectus excavatum is a caved-in appearance of the sternum that gives the chest a triangular shape. In severe cases, the heart and lungs may appear compressed or displaced. The classic sign of pectus carinatum is a rounded, outwardly protruding breast bone that resembles the keel of a ship or pigeon‘s breast.

Additional tests like echocardiography, electrocardiography, and blood work to assess organ function may also be warranted depending on your pup‘s symptoms and overall health status. Crafting a clear clinical picture is essential for mapping out the most effective treatment plan.

Treating Pigeon Chest in Dogs: Surgery and Beyond

Tackling chest bone deformities in dogs is a highly individualized endeavor that requires carefully weighing the risks and benefits of different treatment options. The right approach will depend on a constellation of factors, including the severity of the deformity, your dog‘s age and overall health, and the presence of any symptoms or complications.

For dogs with mild pectus carinatum that isn‘t causing any breathing difficulties or other health issues, the treatment of choice may be no treatment at all. Many mildly affected dogs can lead perfectly normal lives without any intervention. In these cases, the best course of action is often watchful waiting and regular check-ins with the vet to monitor for any changes.

However, for dogs with moderate to severe PC that‘s impacting their quality of life, surgery is usually the most effective solution. The go-to surgical procedure for correcting PC in dogs is called thoracic splinting. Here‘s how it works:

1. Under general anesthesia, the surgeon makes small incisions in the chest wall to access the abnormally protruding cartilage and bone.

2. Using specialized surgical tools, the surgeon carefully reshapes the sternum and rib cartilage, removing any excess tissue.

3. A custom-fitted splint is placed inside the chest wall to maintain the corrected position of the sternum.

4. Over a period of weeks to months, the splint is gradually adjusted to achieve the desired chest contour.

5. Once the chest wall has fully remodeled, the splint is removed in a second surgical procedure.

When performed by an experienced board-certified veterinary surgeon, thoracic splinting has a good success rate for normalizing chest conformation and improving cardiopulmonary function. In a study of 19 dogs treated with splinting, 84% had a significant improvement in their chest wall shape and 79% had complete resolution of clinical signs after an average of 8 weeks.

However, as with any major surgery, complications like infection, splint migration or breakage, uneven correction, or damage to surrounding structures can occur. Weighing these risks with your vet is crucial.

For some dogs, a newer, less invasive treatment called vacuum bell therapy may be an option. This involves placing a suction cup device over the protruding sternum that gradually reshapes the chest using negative pressure. It‘s a promising alternative for puppies with flexible chest walls and no breathing issues.

Nonsurgical treatments like external chest braces, targeted physical therapy exercises, and anti-inflammatory medications may also have a role in mild to moderate cases. Your vet can help you explore which conservative options may be right for your dog.

Coping with the Emotional Challenges

Dealing with a major health issue in your beloved companion is never easy. It‘s okay to feel scared, overwhelmed, or even guilty after a pigeon chest diagnosis. But know this: you are doing everything in your power to give your dog the best life possible.

Connecting with other owners who have been through similar experiences can be incredibly validating and empowering. Your vet may be able to put you in touch with local or online support groups for people with special needs pets. The Facebook group "Dogs with Pectus" is a wonderful resource for practical tips, emotional support, and cute photos of thriving pups.

Also know that it‘s okay to grieve if your dog‘s condition means they won‘t be able to do all the things a "normal" dog can. Maybe they won‘t be able to go on those three-mile runs you envisioned, but focus on what you CAN do together – cuddle on the couch, go for short sniffy walks, learn silly tricks. Your bond is so much deeper than any physical limitations.

The Future of Pigeon Chest in Dogs

While there‘s still much to unravel about pectus deformities in dogs, one thing is clear – the future is bright. Every year brings new insights into the genetic puzzle pieces behind these conditions and novel treatment approaches to help affected dogs live their fullest lives.

As veterinary medicine continues to advance, the prognosis for dogs with even severe chest wall deformities will only get better. Cutting-edge techniques like 3D printed implants and stem cell therapies could transform PC treatment in the coming decade. That said, the most powerful tool in your arsenal will always be your love and devotion.

So keep educating yourself, keep advocating for your pup, and most importantly, keep cherishing every moment you have together. No matter what challenges come your way, you‘ll face them head on, side by side, paw in hand. Because that‘s the unwavering spirit of a true dog lover.