Clinical Experience with the Cairo Anterior Spinal Fixation System (CSS)

Experimental biomechanical testing revealed that the Cairo Anterior Stabilization System (CSS) was as efficient as Kaneda instrumentation. It remained to be tested clinically. Thirty patients having thoracolumbar (T12-L2) burst fractures with and without neurologic deficit were treated surgically by single stage anterior decompression, strut tricortical iliac grafting and stabilization using the Cairo Spinal System (CSS). One case was excluded from the series due to death because of pulmonary embolism 10 days after surgery. All patients had single level fractures. Nineteen cases had recent fractures (up to 10 days), whereas the remaining ten cases had old fractures causing chronic back pain and/or neurologic deficit. Selection of recent cases for anterior surgery was based on the load sharing capacity of the fractured vertebral body. All recent fractured were scored 7 or more by the load sharing classification [6] based on the findings of the preoperative CT and plain radiographs. Twenty-two patients had neurologic deficits ranging from grade A to D3 according to the modified Frankel grading system [2]. In ten cases, the tricortical iliac graft was inserted with its cortical strut, the cortical side of the iliac crest, directed towards the ipsilateral (left) side. The graft width was not enough to cross the midline in three cases, the screws did not penetrate the opposite cortex of the vertebral body in five. All cases but three wore TLSO for 3-4 months. Assessment preoperatively, postoperatively and during follow up visits was based on the neurologic status (using the modified Frankel grading system); the work status and activities of daily living; back pain at the site of spinal fracture (using Denis pain scale); the magnitude of correction and the subsequent loss in correction of kyphosis, scoliosis and translation in the sagittal and coronal planes: and evidence of radiologic fusion. The mean follow-up period was 10.5 months. Our clinical results were compared with the results reported by Kaneda and coworkers [23]. The percentage of patients showing at least one grade of postoperative neurologic improvement in our series was significantly less than those in the comparative study. This was attributed to the high percentage of patients having complete cord or conus lesions in our series. The overall mean initial kyphosis correction in our series was better than that in the comparative study, whereas, the overall mean degree of loss of kyphotic correction in the last follow up visit was greater in our series, mainly due to lack of, or insufficient, postoperative bracing in three of our patients (10.3%). The non-union rates in both series were almost the same, however. Unlike Kaneda series in which the metal failure rate secondary to non-union was 6%, we did not experience any metal failure. Our results in terms of return to work and daily activities, relief of back pain and the grade of tissue invasion (assessed by the mean blood loss, the mean operative time and the complications) were all better than those reported in Kaneda series. From the findings in this study it is evident that CSS is a safe and strong anterior spinal fixator that affords enough stability to enable early ambulation with the maintenance of an accepted alignment and progression to solid fusion with a low rate of complications.