Anterior Cervical Discectomy and Fusion in the Ovine Model

Anterior cervical discectomy infusion is the most common procedure performed around the world for the surgical treatment of cervical radiculopathy or myelopathy. Here we see a disc protrusion compressing the nerve root, which is inflamed. The disc is removed and the nerve root is decompressed.

An antibody cage is then inserted into the disc space to facilitate fusion. Welcome to Monash University, Melbourne, Australia. We are from the departments of surgery and Monash immunology and stem cell laboratories.

This is Professor Graham Jenkin and Professor Ross Young. And I'm Dr.Tony Slager, and today we are going to describe to you how to perform Anor cervical discectomy infusion in the OV model. This video will outline induction of anesthesia level identification, prep, and drape the surgical procedure, insertion of the interbody device and enclosure.

After induction of anesthesia and intubation, the sheep is placed supine on the operating table. The endo fuel tube is then connected to the anesthetic machine and ventilator. An anesthesia is maintained using inhaled volatile gases.

The vital signs are continually monitored and recorded with the oximeter probe secured to the ear. The neck region has already been clipped and cleaned using chlorhexidine and iodine. The neck is extended and everything is kept midline.

This enables clearer visualization of the surface landmarks, which makes level identification easier. A needle is then inserted under the skin, and an x-ray is taken to mark the C3 four disc space. The x-ray is then developed using a digital processor.

An alternative to this is using an image intensifier. You can see on the x-ray screen that the C3 four level is indicated correctly with the needle. The incision is then centered around this point to prep the neck.

A combination of solutions are sprayed on the surgical site, including alcoholic chlorhexidine, alcoholic iodine, and 70%ethanol. These solutions should be allowed to dry and evaporate before starting a drape is placed over the surgical site. We prefer fenestrated square drape, which gives good access and exposure.

The instruments are positioned on the overhead table and the dither and suction are all clipped into place. We recommend using magnification for this procedure. We use loops and a headlight, however, an operating microscope can be used.

If this is available, we prefer to use a longitudinal incision as this facilitates easier access to the vertebral column in the sheep. The incision is then made. Dissection is carried out in a sharp fashion through the investing layers, and then developing a surgical plane medial to the carotid sheath and lateral to the truch and esophagus.

Langle and back or right angle tractors are used until the disc base is identified. Care should be taken at this point to double check that the plane is medial to the carotid sheath. The longest coline muscle is elevated using diathermy, and when adequate exposure is achieved, self attaining retractors are inserted.

These facilitate easy axis to the disc space without the need for constant manual retraction prior to inci the disc. An intraoperative x-rays taken to confirm that this is in fact the correct level After level confirmation, the Caspar distraction pins are inserted into the C3 vertebral body above and the C four vertebral body below. We use 16 millimeter distraction pins.

As the anatomy of the sheep vertebral body is deep and maximal distraction can be achieved safely with a larger size distraction pins prior to distracting the space apart. We recommend in sizing the disc using a 15 scalpel on a long handle. As this relieves the tension and allows for distraction more easily, the discectomy is then carried out using up cutting gers and pituitary gers until a maximal discectomy has been achieved.

Once a disc has been removed, the disc space can be easily visualized. The end plates are then prepared using curettes or a high speed drill until bleeding bone is visualized to enable fusion to occur. The antibody devices then inserted.

In this case, we use a polyether ether ketone or peak cage, which is packed with bone substitute of tri calcium, phosphate and hydroxy appetite and stem cells. However, this model can be used to test a variety of different cages, plates, and matrices, which would be inserted at this time. This is a picture showing the peak cage in position, slightly counter sunk into the C3 four antibody space by two to three millimeters.

Layer closure is then performed of the longest coline muscle, and a sub particular suture is inserted, preferably using an absorbable suture such as Vicryl. The main difference of the human is a concavity in the superior vertebral body, in this case, C3, which contains disc material. This is different to the human where the end plates are more flatly shaped.

There is also a midline ridge in the sheep vertebral body above the disc. Other than these subtle differences in anatomy, the sheep's cervical spine is very similar to the human, and this reinforces the choice of this model for research in this area.