intervertebral disc in canine

[scwon]

*This dog has spondylosis척추증(Spondylosis), which is a form of arthritis due to instability of the vertebrae. This is not necessarily IVD disease. Some dogs with this arthritis are in pain and need medication, while others have no symptoms at all. Cats can get spondylosis also, although it is more common in dogs.

This radiograph of a Pug named addison shows a collapsed disk along with spondylosis between L- 2 and L- 3. You can tell it is collapsed when you compare it to the disk in front and behind.

The arrow points to arthritis in the spine, known as spondylosis(척추증). This is a common problem in many dogs as they age. We have numerous medications at our disposal that willhelp alleviate this painful affliction. 

 

척추증이란 척추에서 발생하는 일종의 퇴행성 변화로,

추간판의 퇴행성 변화에 따른 척추 불안정성에 의해 관절 주위에 형성되는 골극 및 주변 인대의 변성에 의해 발현되는

임상 증후군

*

This dog has IVD disease. There is calcified disk material in the spinal canal between L-2 and L-3, and it is painful and weak in its rear legs.

This radiograph is from an 11 year old dog that is weak on one of its rear legs. The arrow points to the involved vertebrae. Foreign bodies and infections are possible causes, but most likely it is a tumor.

This is the same dog but from the VD view.

Cats can get spinal lesions also. This is the radiograph of a 15 year old cat with a lesion in its spinal canal at the arrow. This cat is painful and not walking well on its rear quarters.

*

Figure 1. A lateral myelogram of a dachshund with a herniated intervertebral disc. Note the loss of contrast column indicating spinal cord compression caused by the ruptured intervertebral disc.

A myelogram showing deviation of the contrast (black arrow) diagnostic of a intervertebral disc herniation.

**

Intervertebral Disk Disease is common in middle-aged and senior dogs and cats. This is what an x-ray looks like (not Maestro’s). Photo by WebDVM.

**

Most disc herniations are near the junction of the thoracic and lumbar spine (T-L junction) however,  cervical (neck) disc disease accounts for about 15% of all canine disc herniations. 

*This side view of a spinal cord model shows 2 vertebrae (V) with a normal disk (D) in between. One of the nerve roots (NR) can be seen coming off of the spinal cord (SC).

To keep you oriented, this is the same area on a radiograph (at L1-2). The nerve root comes out of the dark structure that looks like a horse’s head. The disk, nerve root, and spinal cord do not show up normally on a radiograph. If the disk material becomes calcified it might show up.

This view of a spinal cord model is an end-on view of how the spinal cord fits into the spinal canal. You can see how the spinal cord is enclosed by bone. If it swells it has no place to expand into, resulting in serious damage to the cord.

*Basic anatomy of the

   1;섬유륜,  2:수핵,

원인1.**,protrusion

The left image shows a Hansen type II compression, while the image on the right shows the more common Hansen

Type I.

원인2.**degeneration

Degeneration of the IVD occurs with aging and results in significant changes in its biochemical structure

it is observed most frequently in the chondrodystrophoid breeds 연골이형성품종(dachshund, Pekingese, French bulldog, beagle, basset hound, American cocker spaniel).

**증상.

Disc herniations in the T-L region are generally acute in onset and the clinical signs can range from back pain, to hindlimb ataxia (stumbling and difficulty walking) in the rear limbs to rear limb paralysis.

Most animals suffering from cervical disc herniation  present for acute neck pain.  They often have a stilted gait, a reluctance to move their head and a lowered head stance.  About 10% of dogs will have tetraparesis (neurologic dysfunction of all 4 legs) and a portion of these animals will be non-ambulatory.  Some with dogs with cervical herniations may present for a one sided forelimb lameness known as a “root signature”.  This results from a disc herniation at the rear of the cervical spine impinging on the nerves providing function to the affected limb.

cf)

8 year old male neutered Border Collie with azotemia identified on bloodwork. More lameness on left pelvic limb in the last 3 weeks, stiff and rigid on physical exam.

**치료.

The optimum dose of dexamethasone has not been determined; however, some guidelines can be offered. Severe or acute spinal cord compression following a cervical IVD protrusion is treated with 2.0 mg/kg intravenous dosage. This initial therapy is followed by more conservative doses (0.2 mg to 0.4 mg/kg sid or bid) for 2 to 3 days or as needed. More subtle episodes are treated with the conservative dosage initially. The possible side-effects of corticosteroid therapy should be discussed with the client before initiating therapy.

Muscle relaxants have been recommended in cervical IVD disease manifested by severe muscle spasms. (64) Methocarbamol and chlorphenesin carbamate have been used effectively for this purpose. The recommended dosages are as follows:

Methocarbamol: 10 mg/kg PO as a loading dose and 5 mg to 19 mg/kg PO tid thereafter (32) Chlorphenesin carbamate: 50 mg/kg divided into three doses for the first day, followed by 25 mg/kg PO divided into three doses per day thereafter (32)

Cage rest (no physical activity or leash exercise only) is employed in all regimens of medical management. When corticosteroid therapy is used, cage rest is mandatory, since alleviation of pain may encourage the patient to exercise. Exercise in the presence of clinical IVD disease may result in extrusion of additional disk material and subsequent severe neurologic damage. (28,54) if the owner refuses hospitalization of the patient, confinement without corticosteroid therapy is highly recommended