Preliminary results of the direct transplantation of mesenchymal stem cells injected into the compressed spinal cord during inter body fusion using Seattle Slew implants in 3 horses
[um_loggedin show_lock=yes]Authors: Grant BD, (1) Hopper SM, Reed S, Woodie B (2) , Lepage OM, Francois I (3)
Affiliations: (1) Barrie Grant Equine Consultant, Bonsall, California, (2) Rood and Riddle Equine Hospital, Lexington KY (3) University of Lyon, Vetagro Sup, Veterinary Campus, ICE-GREMERES Lyon Equine Research Center, France
Introduction: The surgical treatment for cervical cord compression in the horse was first described in 1979 (Wagner,, Grant et al ). The original technique used small autologous bone dowels hammered into a prepared round hole placed in the center of the affected level. The technique has evolved to the use of a Titanium threaded implant (Seattle Slew ) that is threaded into the prepared site and filled with the harvested bone graft from the drilling procedure. The compression in the dynamic cases is reduced immediately and within 8 weeks with static compression . While there is some immediate improvement in clinical signs it can require up to a year to allow for the damaged spinal tracts to regain function.
Hypothesis/Objectives: The augmentation of the fusion technique with the transplantation of stem cells injected directly into the compressed cord should reduce the time required to regain maximum improvement in clinical signs. The technique was developed using 8 normal standardbred horses and has been described by Francois, Lepage , Grant et al. We propose that the same technique be used on a small group of horses with cervical cord compression to see if there is any increase in morbidity.
Materials and Methods: 3 male horses (2 thoroughbred (TB) geldings and 1 Tennessee Walker(TW) stallion with compression of the cervical cord compression as demonstrated with myelograms were used. One TB was graded a 2/5 and the Tb a 3/5 . The TW was a grade 4/5. One TB had compression in flexion only at C3/C4 and the other horses had compression in flexion only at C3/C4 and C4/C5.
All 3 horses had an anterior cervical fusion performed using a Titanium implant ( Grant et al ) . After the implant was firmly in place a 22 gauge spinal needle was inserted thru the intervertebral disc towards the spinal canal. When a distinct change in resistance was detected the stylet was removed and CSF flowed freely. The needle without the stylet was then advanced into the spinal canal until there was cessation of CSF. Then 0.5 ml of umbilical derived mesenchymal cells were injected. There was a noticeable contraction of the front legs at the time of injection. The implant was then filled with the prepared bone graft ( debris from the drilling procedure ) and the tissues closed as previously described. All three horses had assisted recoveries.
The 3 horses had box stall confinement for 60 days followed by 60 days of handwalking before being allowed exercise in a paddock.
Results: All 3 horses survived the procedure with no detectable morbidity.All horses recovered smoothly from anesthesia. The Tb’s both stood within an hour following the cessation of surgery. The TW required 4 hours. All three horses had primary healing with no excessive swelling although the double level Tb did have a seroma that resolved without intervention within 4 weeks.
All 3 patients had improvement in clinical signs within the first year following the procedure. The single level Tb raced nine times at the Southern California racetracks finishing 3rd in a maiden allowance race in his first start. He is now performing as a show horse in Pony Club competition. The second TB is now being used as a stock horse and the TW is now a carriage horse.
Conclusions: The augmentation of the anterior cervical fusion procedure for the treatment of cord compression can be performed with minimal morbidity. Without the use of a significant number of patients and controls and pre operative subjective gait analysis it is not possible to state that there was a reduction in time for clinical improvement.
Acknowledgements, Funding, and Conflicts of Interest: The stem cells were supplied by Dr. Scott Hopper of Rood and Riddle. All three horses were owned by Barrie Grant Equine Consultant. The myelogram and hospitalization expenses of the TW were provided by the University of Tennessee. The myelogram and hospitalization of the Double level TB was provided by California Equine Orthopedics and Dr. John Newcombe provided his long term care.[/um_loggedin]