Cervical Vertebral Stenotic Myelopathy.

Cervical vertebral stenotic myelopathy is a common cause of ataxia in horses secondary to spinal cord compression. Early articles describing this problem indicate genetic predisposition as a known risk factor. Further studies have shown the problem is a developmental abnormality which might have genetic predisposition and environmental influences.

Mesenchymal stem cell transplantation into the spinal cord of healthy adult horses undergoing cervical ventral interbody fusion.

OBJECTIVE: To determine the feasibility of umbilical cord-derived mesenchymal stem cell (UC-MSC) transplantation into the cervical spinal cord of horses by using fluoroscopy with or without endoscopic guidance and to evaluate the neurological signs and tissue reaction after injection. STUDY DESIGN: Experimental study. ANIMALS: Eight healthy adult horses with no clinical signs of neurological disease. METHODS: After cervical ventral interbody fusion (CVIF), ten million fluorescently labeled allogeneic UC-MSC were injected into the spinal cord under endoscopic and fluoroscopic guidance (n = 5) or fluoroscopic guidance only (n = 3). Postoperative neurological examinations were performed, and horses were humanely killed 48 hours (n = 4) or 14 days (n = 4) postoperatively. Spinal tissues were examined after gross dissection and with bright field and fluorescent microscopy. RESULTS: Needle endoscopy of the cervical canal by ventral approach was associated with intraoperative spinal cord puncture (2/5) and postoperative ataxia (3/5). No intraoperative complications occurred, and one (1/3) horse developed ataxia with cell transplantation under fluoroscopy alone. Umbilical cord-derived MSC were associated with small vessels and detected up to 14 days in the spinal cord. Demyelination was observed in six of eight cases. CONCLUSION: Fluoroscopically guided intramedullary UC-MSC transplantation during CVIF avoids spinal cord trauma and decreases risk of ataxia from endoscopy. Umbilical cord-derived MSC persist in the spinal cord for up to 14 days. Cell injection promotes angiogenesis and induces demyelination of the spinal tissue. CLINICAL SIGNIFICANCE: Umbilical cord-derived MSC transplantation into the spinal cord during CVIF without endoscopy is recommended for future evaluation of cell therapy in horses affected by cervical vertebral compressive myelopathy.

Arthrodesis of the equine centrodistal and tarsometatarsal joints using a single modified kerf-cut cylinder.

OBJECTIVES: To describe a technique for surgical placement of a modified kerf-cut cylinder for the purpose of arthrodesis across the equine centrodistal and tarsometatarsal joints. METHODS: Each horse (n = 4) underwent unilateral placement of a single kerf-cut cylinder spanning the centrodistal and tarsometatarsal joints with the placement of an autologous cancellous bone graft. Horses were evaluated via lameness examination and radiography postoperatively and euthanatization of each horse was performed at four different time points up to 12 weeks post-surgery to evaluate for lameness, implant stability and success with integration in the surrounding bone. RESULTS: Implants were placed successfully in three of four horses. In one horse, due to technical error, the implant was misaligned with the joint spaces. Although the horse exhibited minimal pain, it was euthanatized at the two week follow-up. Implant placement in the remaining three horses was successfully achieved. At eight weeks, radiographically there was evidence of osseous union across the joint spaces. No change in lameness was detected at any point after surgery. At 12 weeks post-surgery, histologically the implants were filled with mineralized osteoid and demonstrated integration with the surrounding tissue. CLINICAL SIGNIFICANCE: The surgical approach and placement of modified kerf-cut cylinders for arthrodesis of the centrodistal and tarsometatarsal joints were successfully achieved with minimal signs of postoperative pain and a short rehabilitation time period in normal horses.

In vitro biomechanical evaluation of four surgical techniques for fusion of equine centrodistal and tarsometatarsal joints.

OBJECTIVE To evaluate the biomechanical properties of 4 methods for fusion of the centrodistal and tarsometatarsal joints in horses and compare them among each other and with control tarsi. SAMPLE 24 sets of paired tarsi without substantial signs of osteoarthritis harvested from equine cadavers. PROCEDURES Test constructs (n = 6/type) were prepared from 1 tarsus from each pair to represent surgical drilling; 2 medially to laterally placed kerf-cut cylinders (MLKCs); a single large, dorsally applied kerf-cut cylinder (DKC); and a dorsomedially applied locking compression plate (DMLCP). Constructs and their contralateral control tarsi were evaluated in 4-point bending in the dorsoplantar, lateromedial, and mediolateral directions; internal and external rotation; and axial compression. Bending, torsional, and axial stiffness values were calculated. RESULTS Mean stiffness values were consistently lower for surgical drilling constructs than for contralateral control tarsi. Over all biomechanical testing, surgical drilling significantly reduced joint stability. The MLKC constructs had superior biomechanical properties to those of control tarsi for 4-point bending but inferior properties for external and internal rotation. The DMLCP and DKC constructs were superior to control tarsi in dorsoplantar, rotational, and axial compression directions only; DMLCP constructs had no superior stiffness in lateromedial or mediolateral directions. Only the DKC constructs had greater stiffness in the mediolateral direction than did control tarsi. Over all biomechanical testing, DMLCP and DKC constructs were superior to the other constructs. CONCLUSIONS AND CLINICAL RELEVANCE These biomechanical results suggested that a surgical drilling approach to joint fusion may reduce tarsal stability in horses without clinical osteoarthritis, compared with stability with no intervention, whereas the DMLCP and DKC approaches may significantly enhance stability.

Retention of surgery specialists in academia: a critical agenda.

Recruitment and retention of specialists to academia appears to be a growing problem in university teaching hospitals. Members of the American College of Veterinary Surgeons (ACVS) believe that the movement of surgery specialists to practice may have an impact on the training of veterinary students and surgery residents. To address these concerns, 1,071 ACVS diplomates and 60 department heads and hospital directors from all veterinary schools in North America were surveyed to determine whether a problem exists, the extent of the problem, and potential reasons for migration of specialists to practice. Responses were obtained from 620 ACVS diplomates (58 per cent) and 38 department heads and hospital directors (63%) from 28 different universities. The responses confirmed a net movement of surgery specialists from academia to practice. Eighty seven percent of department heads and hospital directors believed there was a shortage of small animal surgery specialists in academia; this information was supported by the fact that 47% responded that they had open positions and 68% had difficulty filling positions in the last five years. The demand was slightly less for large animal surgery specialists, and 42 per cent of respondents indicated that they had open positions. Financial considerations were the most common reason for surgery specialists to move from academia to private practice. Seventy-six percent of responding ACVS diplomates in private practice had a total compensation package valued at greater than $125,000 per year, whereas 77.8% of diplomates in academia had total compensation valued at $125,000 or less. Most universities offer starting salaries (not including benefits) for recently certified surgery specialists ranging from $70,000 to $90,000. Reasons for moving from academia to practice besides financial considerations included undesirable location of university hospitals; lack of interest in research; and a belief that university administration was not supportive of surgery specialists. Many academic surgery specialists were frustrated by the requirement for productivity in research, teaching, and service for promotion in tenure-track positions.