Picture of a young English bulldog affected with spina bifida — Photo by Don Preisler

Spina Bifida in Dogs

by Amy Young
July 08, 2024

What is spina bifida?

Takeaways

Spina bifida is a developmental disease that results from improper formation of the spine.
Spina bifida can cause orthopedic and neurologic problems in affected animals.
Spina bifida is relatively rare in dogs and is likely due to genetic and environmental factors.
The prognosis for severe cases has historically been poor, but a novel approach pioneered at UC Davis that combines surgery and stem cell treatment has achieved promising results.

Spina bifida is a condition that results from improper formation of the spine during embryonic development. The vertebrae of the spinal column normally surround and protect the spinal cord, the part of the central nervous system that connects the brain to the rest of the body. Spina bifida is a birth defect that causes incomplete closure of the spine and damage to the spinal cord and nerves. This developmental disorder often occurs in the lower back region, but can happen anywhere along the spinal column. Severe cases may involve multiple vertebrae.

In the most severe cases, the spinal cord and associated membranes protrude through the open areas of the spine. This is classified as spina bifida aperta (open) because the nervous tissue is visible outside of the body and is exposed to the environment. These cases are rare and have a high level of mortality before, or shortly after, birth. Other subtypes in which the spinal cord is not exposed include spina bifida cystica (closed), which presents with externally visible abnormalities such as bumps along the back, and spina bifida occulta (hidden), in which external abnormalities are not visible. The latter is often only discovered when X-rays are taken for unrelated issues. English Bulldogs are the most common breed affected by spina bifida, but any breed can be affected.

What are the clinical signs of spina bifida in dogs?

Clinical signs of spina bifida in dogs vary depending on the area of the spine affected and the involvement of neural structures. Most affected dogs will show signs of spina bifida within the first several weeks after birth. Typically, dogs will exhibit varying degrees of hind leg weakness and poor muscle tone, with abnormal use of their tails. They often have urinary and fecal incontinence, characterized by dribbling urine and poor control of defecation. Urinary tract infections are common side effects of spina bifida. Other clinical signs may include hair and skin changes on the back, skin lesions, and visible depressions on the spine. Clinical signs generally worsen as the dogs grow, with progressive hind leg weakness and even paralysis.

How is spina bifida diagnosed?

Spina bifida is primarily diagnosed by imaging of the spine. X-rays and computed tomography (CT) can identify abnormalities to the vertebrae, but magnetic resonance imaging (MRI) is preferred because it provides a detailed evaluation of the spinal cord, nerves, and membranes covering the nervous tissue. Blood and cerebrospinal fluid samples may be evaluated to rule out other conditions.

How is spina bifida treated?

Treatment for spina bifida in dogs depends on how many vertebrae are affected and where they are located. Mild cases often do not require treatment, but may need supportive care to manage incontinence, UTIs, and other hygiene issues. Combinations of medications, physical therapy, wheelchairs/braces, and dietary modifications may improve the quality of life for affected dogs. Surgical correction can be performed in dogs, but surgery alone will not reverse clinical signs. Moreover, many dogs continue to have progressive neurological deficits despite surgery and many dogs are euthanized.

Groundbreaking research at the UC Davis Schools of Medicine and Veterinary Medicine is changing treatment options for spina bifida. Studies in affected English Bulldogs have demonstrated that applying canine placental stem cells with a tissue-engineered scaffolding to the nervous tissue at the time of surgery improved range of motion and limb control. Treated dogs are able to run, play ball, and live a full life. They still require diapers for incontinence, a hallmark of spina bifida that researchers are hoping to fix with further refinements to the approach.

Thanks to a university-wide collaboration between veterinarians, physicians, researchers, and biomedical engineers utilizing the canine model, UC Davis Health announced the launch of the world’s first, FDA-approved human clinical trial using stem cells before birth to treat the most serious form of spina bifida. The one-of-a-kind treatment will be delivered while the baby is still in the mother’s womb (in utero). It will be the standard surgical procedure combined with the use of the stem cell “patch” to repair the defect before birth.

What is the prognosis for spina bifida?

The prognosis for spina bifida is generally excellent for dogs that are clinically normal, and good for those with mild disease. The prognosis is often poor for affected dogs that exhibit substantial neurological deficits, but advanced surgical approaches are providing new hope for severely affected animals.

How can spina bifida be prevented?

Spina bifida is relatively rare in dogs and is likely due to a combination of multiple genetic and environmental factors. A mode of inheritance for spina bifida has not been identified in any dog breeds to date. Known environmental factors include toxin exposure and nutritional imbalances (such as folate deficiency) during pregnancy. Breeders should avoid breeding affected dogs.