Introduction

Fracture-luxations between T11 and L6 occur in 50-60% of spinal fracture patients subsequent to trauma. The relatively small diameter of the vertebral canal impacts outcome negatively. Conventional management includes pins or screws and polymethylmethacrylate (PMMA), vertebral body plating, modified segmental vertebral fixation, dorsal spinous plating, and external fixation (ESF). The purpose of this report is to describe a technique that improves pin purchase in and alignment of vertebral bodies and successfully manages vertebral fracture-luxation.

Materials and Methods

Four cats had radiographic evidence of spinal fracture-luxation following trauma. A standard dorsal midline approach was performed with hemilaminectomy at the affected site. Two IMEX interface pins^TM were placed into the vertebral bodies immediately cranial and caudal to the fracture-luxation site on the side of hemilaminectomy. The pins were placed at the junction between the lamina and the pedicle where it had been exposed by hemilaminectomy. A rod connecting the negative profile pins with clamps secured the vertebrae in appropriate orientation. Lyostypt^TM (Braun) was placed over the spinal cord. Wooden spatulas were placed on either side of the pins as a mould to protect the spinal cord and soft tissues; PMMA in semi-liquid phase was moulded around the pins.

Results

The average age of cats presented with fracture luxation was 2.5 years (range 1-6 years 10 months). Two cats had no motor function with intact sensory function; one cat had loss of motor and sensory function. One was non-ambulatory with sensory but poor motor function. Three cats with sensory function preoperatively regained ambulation with residual neurological deficits. One cat without sensory or motor function was euthanased six weeks post operatively without change. Sensory function was lost in one cat post-surgery but this returned at four weeks; this was the only complication associated with surgical intervention. The period of post-operative hospitalisation was 8-45 days (average 25 days), with one cat still currently under treatment.

Discussion

Patients with severe traumatic thoracolumbar spinal cord injuries are often euthanased without benefit of treatment. Surgical success is possible, however the rehabilitation period may be protracted and residual neurological deficits are likely. Hemilaminectomy aids reduction, accurate pin placement and pin purchase in adequate vertebral body bone stock. Use of temporary linear ESF aids reduction and use of IMEX interface pins^TM improves bonding at the pin- PMMA interface, further contributing to stability.