Spinal Fractures and Lumbosacral Disease in Cats: Pins and Pmma

Vertebral fractures and luxation are a common cause of neurologic injury in cats, most frequently because of road traffic accidents, animal attack and falling from a height. They usually occur at the junction between stable and more mobile areas of the spine. The terminal thoracic region is most affected followed by sacrococcygeal, lumbar and cervical. There is some debate whether conservative or surgical management is most appropriate in individual cases. The objective of surgery in such cases is to decompress the spinal cord, reduce the fracture/luxation and provide rigid stabilization of the vertebral column. In human patients, pseudo-arthrosis formation after unsuccessful vertebral fusion has been associated with chronic neurogenic pain. Therefore, implants providing rigid stability are considered advantageous. Vertebral body plating, vertebral stapling, cross pins, screws or pins and cement and external skeletal fixation have all been described. Degenerative lumbosacral stenosis (DLSS) is a commonly recognized neurologic condition in dogs, but poorly documented in cats. It is believed that the incidence of DLSS could be similar than the described in dogs but may frequently go unnoticed or undiagnosed. Components of this disease syndrome include intervertebral disc degeneration (IVDD), facet joint osteophytosis/malformation, spondylolisthesis and discospondylitis. Clinical signs may include lumbosacral pain, hyperesthesia, pelvic limb paresis, unilateral or bilateral pelvic limb lameness and urinary and/or fecal incontinence. Though anomaly (especially mismatch in vertebral alignment) may be evident radiographically, MRI and CT scans are superior modalities in terms of sensitivity and specificity. There is a paucity of surgical reports in the veterinary literature and intervention has primarily been documented by dorsal laminectomy and annulectomy, with only sporadic case reports of stabilization. Recurrence of clinical signs following decompression alone has been described as 18% in one study (Danielsson) and 16.7-54.5% in another (Linn). High recurrence rates may be due at least in part to underlying dynamic instability with associated ongoing impingement of the cauda equina and L7 nerve roots. Appropriate stabilization would potentially prevent such impingement and may also prevent exuberant formation of fibrous tissue that could cause nerve root compression. Six cats with vertebral fracture-luxation and six with lumbosacral pain were identified and treated by the author between 2007 and 2010. Signalment data were collected regarding breed, sex, age, weight, history (type of trauma, duration and progression of the clinical signs), neurological assessment (preoperatively, postoperatively, at discharge and at six weeks post-operative recheck). Diagnosis was based on neurological examination, digital radiographs and magnetic resonance imaging. The preoperative neurological status for each cat was graded using a 5-point scale adapted from Matthiesen. All cats were allowed home to cage-rest confinement when voluntary urination was evident and motor function was apparent for all four limbs. Radiographs were taken 6 weeks after surgery for all cats. Passive range of motion physiotherapy and assisted standing and proprioceptive feedback exercises were performed for all trauma patients for four to six weeks post-operatively but not for any cats treated for lumbosacral pain. Poor outcome was defined as persist difficulty in voiding urine and/or no improvement in gait after treatment. Functional recovery was defined as the cat becoming an acceptable household pet in terms of bladder control and the ability to undertake unassisted and pain-free ambulation. Excellent recovery was ascribed to cats manifesting normal urination and no gait or proprioception abnormalities.