Authors of section

Author

Anton Fürst

Executive Editor

Jörg Auer

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Arthrodesis with plates

1. Principles/General considerations

Cervical stenotic myelopathy (CSM) is a developmental disorder, usually causing spinal ataxia in young horses. Cervical vertebral deformation leads to stenosis of the vertebral canal and spinal cord compression.

CSM is commonly diagnosed in foals and young horses between 6 months and 3 years of age and is more prevalent in male and Thoroughbred horses.

arthrodesis with kerf cut cylinder

Depending on the localization of the instability, two or three vertebrae are fused.

cervical instability

This decision is made based on the myelography images.

arthrodesis with kerf cut cylinder

2. Preparation and approach

This procedure is performed with the patient positioned in dorsal recumbency through the ventral midline approach to the cervical spine.

plate fixation with atlantoaxial arthrodesis

3. Realignment

Preparation of the bone

The ventral spinous process of the body of the affected vertebrae is flattened slightly using a curved osteotome and bone rongeur.

arthrodesis with kerf cut cylinder

The disc material has to be removed, at least partially, with multiple parallel drill lines with a 5.5mm drill bit under radiographic guidance.

arthrodesis with plates

Realignment

After exposing the ventral surfaces of the affected vertebrae, the alignment is corrected and maintained with bone-holding forceps.

arthrodesis with plates

4. Fixation

Plate selection

Preferentially, the LCP is used for the fixation of the instability. According to the size of the patient, a small or broad 3.5/4.0 or 4.5/5.0mm LCP is used.

plate fixation with atlantoaxial arthrodesis

Plate preparation

Minimal plate bending is needed.

arthrodesis with plates

Plate application

With the bone-holding forceps in position, the appropriately sized plate is applied to the ventral aspect of the affected vertebrae.

arthrodesis with plates

One cortex screw is inserted into each vertebra in load fashion. The correct length of the screws is determined with the help of fluoroscopy.

Note: Attention must be paid not to damage the spinal cord.

arthrodesis with plates

The remaining holes are filled with locking-head screws.

arthrodesis with plates

5. Closure

The muscles, subcutaneous tissue and the skin were closed in a continuous fashion. A close active drain can be placed at the level of the plate, exiting the skin near the incision and sutured to the skin.

A stent bandage is applied, and covered with an adhesive barrier drape to keep the incision clean and dry during recovery.

plate fixation

6. Case example

1.5-year-old Warmblood foal with instability of C3-C4-C5.

The instability is not visible on straight lateral radiographs.

arthrodesis with plates

Preoperative myelography showing the instability of C3-C4-C5 (arrows).

arthrodesis with plates

The instability was treated by performing an arthrodesis of C3-C4-C5. Intraoperative image showing screw insertion in lag fashion during fluoroscopic control.

arthrodesis with plates

Postoperative radiograph showing stable fixation of C3-C4-C5.

arthrodesis with plates

Follow up at 3 months.

arthrodesis with plates

7. Aftercare

Following surgery, antibiotics and NSAIDs are routinely administered for 3 days. If indicated, they need to be continued.

Routinely follow up radiographs are taken immediately after surgery and after 2 and 4 months.

The rehabilitation protocol includes 2 months of stall confinement, followed by 1 month of hand-walking, and 2 months of progressive exercise.

Only when the ataxia has completely disappeared, the horse can return to training or other activities.

plate fixation with atlantoaxial arthrodesis

Implant removal

There is no need for implant removal, except in cases of implant loosening or surgical site infection.