Last week Pasha suddenly developed a limp on her right hind leg. Pasha is a three-year-old female French bulldog that looks like an animated soft toy. Full of character, French bulldogs are a small breed of dog that have recently become more common in Malta thanks to their smaller size and loving character. Until this limp, Pasha had hardly ever needed veterinary care other than routine check-ups, vaccinations and preventive treatments, but this was different.

Her owners explained that the limp had suddenly flared up when they moved from an apartment to a large house that included a garden. Since the move, Pasha had been having the time of her life tearing madcap up and down the stairs and all around the garden. Initially, they had dismissed the limp as a minor sprain due to the unaccustomed exercise, but when the limp persisted, they got worried.

Cuddly as Pasha may be, she hates being taken to the vet, so she does tend to put up resistance to being examined. After a couple of attempts, it was obvious that we would need to sedate her to be able to properly examine her and maybe even take X-rays of her pelvis and spine.

The physical examination turned up nothing to worry about. Working from the ground up, her feet were first checked for grass seeds or burrs that typically get trapped between the pads. Nothing there. Neither was there signs of a foreign body that might have worked its way into the soft flesh. Further up the leg, I found that her knee flexed and rotated naturally, there was no looseness in the knee joint and no sensation of crepitation or crunching that might point to an injury of the patella or cruciate ligaments.

So we decided to focus our examination further up and take an X-ray of her pelvis and spinal area. The pelvis was fine. The femoral bone was well in place and clearly defined. No arthritis and no dysplasia of the hip. However, the X-ray of Pasha’s spine was not so good. At levels T10 and T11 of her spine, the probable cause of her sudden limp became apparent. Pasha has hemivertebra.

Within the genus tree that classifies all living matter, the division of animals that have a vertebral column, appropriately called vertebrata, occurs quite early within the tree structure. Vertebrata features towards the beginning of the tree because it is common to many animals. Included in this group are mammals, fish, reptiles and birds.

Dogs diagnosed with hemivertebra should be not be used for breeding purposes, as the defect could be passed on to the next generation

The vertebral column itself consists of a series of segmented bones, called vertebrae, articulated and separated by discs and ligaments. These vertebrae give the animals an advantage, either in size, strength, flexibility or all three qualities put together, and which is unattainable by other members of the animal kingdom that are classified as invertebrate, that is, without a spine.

As always, anatomy has ingenious ways, and not only does the vertebral column serve for its mechanical structure but also as a protection for the distribution of the main nerve fibres connecting the brain to the rest of the body. It does this by housing the nerve tissue which runs down the length of the vertebral column called the spinal cord.

Dogs typically have seven cervical or neck vertebrae numbered C1 to C7. They have another 13 thoracic or chest vertebrae numbered T1 to T13, seven lumbar vertebrae numbered L1 to L7, three fused vertebrae which form the sacrum or pelvis and then anything from three to 20 coccygeal vertebrae which form the tail.

There are various congenital spinal and vertebral defects that occur in dogs. In brachycephalic breeds, having a flattish face and wide skull, such as pugs, Boston terriers, English bulldogs and French bulldogs like Pasha, the defect we refer to as hemivertebra is one of the most prevalent. Since Pasha’s defect was present at levels T10 and T11 of her spine, this meant that the problem was in the thoracic or chest area.

Hemivertebra is when only half of a vertebra develops. The external symptoms of hemivertebra will depend on the number and severity of the vertebrae involved, yet it is very possible that no external signs or symptoms will ever become apparent and sometimes the only way to investigate this is by X-ray examination. Whenever there is an alteration of a vertebra, be it due to trauma, degeneration or, as in our case, genetic reasons, the main concern is the effect this may have on the delicate spinal cord nerve tissue, which is in such close proximity. Up to the stage when Pasha lived in an apartment, the consequences of her hidden defect went unnoticed. As soon as she moved to her new house and suddenly became so much more active, the underlying defect outwardly manifested itself with a limp.

Luckily, Pasha’s spinal cord was not compromised. However, dogs diagnosed with hemivertebra should be not be used for breeding purposes, as the defect could be passed on to the next generation.

Anyone contemplating purchasing such a breed should be aware of the possibility of this condition. The good news is that it is a defect that brachycephalic breeds can and should be screened for. This is not to say that brachycephalic breeds should not be considered as a pet. On the contrary, I know many households that have happy brachycephalic dogs without hemivertebra. Your veterinarian will be a good source of advice in this regard.

Pasha was both unlucky and lucky. Unlucky to have the condition, but lucky to have caring owners. She was immediately placed on appropriate medication. Within a few days, her owners informed me that she was almost back to normal.

Now that they are fully aware of her condition, they monitor her carefully and do their best to contain her enthusiasm. In time, the excitement of Pasha’s new surroundings will subside and hopefully she will enjoy a relatively trouble-free life.

thisweekwiththevet@gmail.com

Dr Martin Debattista is a veterinary surgeon.