Experimental model of posttraumatic syringomyelia: the role of adhesive arachnoiditis in syrinx formation

Abstract

An experimental model was devised to elucidate the role of spinal blockade in posttraumatic syringomyelia. Thirty-eight Japanese White rabbits, each weighing about 3 kg, were used in this study. The animals were divided into four groups: in Group 1, eight animals received traumatic injury only; in Group 2, 12 animals received traumatic injury following injection of 100 mg kaolin suspended in 1 cc normal saline solution into the subarachnoid space at the site of trauma; in Group 3, nine animals received traumatic injury following injection of 200 mg kaolin in 1 cc normal saline solution into the subarachnoid space at the site of trauma; and in Group 4, nine animals without traumatic injury received an injection of 200 mg kaolin in 1 cc normal saline solution into the subarachnoid space. The subjective criteria for syrinx formation were the presence of a definite round cyst having a smooth margin and an upper or lower extension of more than 2 cm from the injured site. Syrinx formation was seen in 12.5% (one of eight rabbits) in Group 1, 41.7% (five of 12 animals) in Group 2, 55.5% (five of nine rabbits) in Group 3 and 0% (none of nine animals) in Group 4 (p < 0.05). There was a tendency for the combined trauma/kaolin injection groups to be more prone to develop a syrinx. In the kaolin injection only group (Group 4), no animal showed a definite cyst or an extending cavity during the experimental period. The results suggest that kaolin enhances the extension of multiple small cavities that have already formed at the time of initial injury. The difference between the frequency of syrinx formation and the time of survival was statistically significant well beyond the 0.05% level. The overall difference, relating to the frequency of syrinx development, group, and duration of survival, was also statistically significant. In summary, subarachnoid block secondary to adhesive arachnoiditis is important in initiating the extension of the syringomyelia cavity.

Post-traumatic syringomyelia and post-traumatic spinal canal stenosis: A direct relationship: Review of 75 patients with a spinal cord injury

“…The review of standard X-rays, taken at the time of this study, showed kyphosis in 60% of the cases (45), with a mean angle of 18.28 (5 ± 808), equal or greater to 308 in 36% of the cases (27). The percentage of spinal canal stenosis measured by CT scan re¯ects the quality of the reduction ( Figure 5).…”

“…The contusion was most often visualised (27 cases ie 36%), followed by syrinxes (21 cases 27.5%) showed a non statistical signi®cance. The occurrence of a syrinx had no correlation with the initial extent of the lesionsyndrome, this being on average 3.6 levels in the absence of a syrinx as opposed to 4.5 levels with a syrinx.…”

“…Other authors pointed to the major role of phenomenon of tethered cord in the genesis of syrinx, considering it as an essential prerequisite, and underlining the constance of arachnoiditis. 21 The experimental study of Cho 27 on rabbits con®rms the major role of subarachnoid blockage in the pathogenesis of syrinx.…”

Factors associated with early onset post-traumatic syringomyelia

“…Processes postulated to be involved include: 'slosh and suck' at the site of injury, liquefaction, development of hematoma, a malacic change in the spinal cord, necrosis, enzymatic lysis, tissue loss and arachnoiditis. 7,8 Several studies have been sought to identify clinical and radiological factors associated with post-traumatic syringomyelia. Factors examined include: age at onset, gender, cause of injury, site of injury, severity of injury, type of vertebral fracture, treatment method and the degree of encroachment into the vertebral canal.…”

Perilesional myeloradiculopathy with tethered cord in post-traumatic spinal cord injury

“…4 Edgar and Quail emphasised the role of the tethered cord in both forms of PTMs. 3 Many works have confirmed the causal link between arachnoiditis and syrinx 15,16 or myelomalacic myelopathies. 17 In our study, all of the patients had spinal lesions that were located at the subaxial cervical spine or at the thoracolumbar junction.…”