Prophylactic, Intrathecal Steroids Could Improve Recovery after SCI

By: Peter Pollack

Peter Pollack

Intravenous steroids administered prophylactically can help protect the spinal cord from injury during high-risk spinal deformity surgery, but they also increase the risk of other complications, especially in pediatric patients. According to data from a rat study presented yesterday at the AAOS Annual Meeting, steroids administered intrathecally may offer similar protective benefits while reducing the risk of complications.

“Rat spines are small, so we’re quite certain that we were not actually giving an intrathecal injection,” explained Thomas J. Errico, MD, lead author of “Prophylactic Intrathecal Steroids Has a Protective Effect in a Spinal Cord Injury Model.” “However, we noted the prophylactic effect, and the literature suggests that if you injure the dura, the epidural steroids enter through the dura at the injury site. We believe that’s the mechanism by which the steroids are moving intrathecally and having an effect.”

Dr. Errico and his team induced incomplete spinal cord injuries in the rats by introducing a small embolectomy Fogarty catheter through a T10 laminotomy and inflating the catheter to compress the spinal cord. The rats were divided into the following three groups:

  • Group 1—treated with prophylactic intrathecal methylprednisolone injection immediately prior to spinal cord injury (SCI)
  • Group 2—treated with intrathecal normal saline (NS) immediately prior to SCI
  • Group 3—sham surgery without SCI, treated with intrathecal methylprednisolone injection

Blinded evaluators followed the rats once weekly for a period of 6 weeks using the Basso-Beattie-Bresnahan (BBB) standardized spinal cord clinical classification.

Rats treated with prophylactic local methylprednisolone prior to mechanical SCI recovered faster and to a significantly greater extent compared to those treated with saline only. Administration of methylprednisolone without SCI did not have any observable negative effect.

Excellent results
Rats in Group 1 displayed a significant recovery to more than half their natural functional ability after 6 weeks—indicated by an average BBB score of 11.8 (out of 21). In contrast, at 6-week follow-up, NS pretreatment seemed to have negligible protective effects from SCI (the average BBB score for Group 2 was 0.5 at 6 weeks).

“The treatment was much more effective than I thought it would be,” said Dr. Errico. “We saw a 10-point change on the BBB scale in some of the animals.”

According to Dr. Errico, the increase in the incidence of SCI in spine surgery prompted his study. New instrumentation and complex surgical procedures are among the reasons he cited for the increase. “Although the prevalence of SCI was just 0.5 percent in 1979, more recent reviews have determined this number to be as high as 17 percent for neurological complications and 4 percent with paralysis for high-risk patients and procedures,” he said.

He also noted that contusions and compressions of the spinal cord—such as the ones inflicted on the rats in this study—cause most injuries and can result in loss of motor and sensory function. In these injuries, the primary lesion is gradually enlarged by delayed secondary damaging processes, which may begin minutes after SCI and continue for days to weeks.

“Although current methods highlight the importance of immediate intravenous administration of steroids after SCI, the emphasis on treating spinal cord trauma at the earliest possible time has led to the hypothesis that a prophylactic, local injection of methylprednisolone would provide maximal and immediate steroid effect, while eliminating the potential for systemic complications,” he wrote.

Dr. Errico stated that the logical next step is another rat study to determine whether the steroid treatment remains efficacious even if it is administered soon after SCI. He also believes it is reasonable to consider a large, multicenter clinical trial.

“Using steroids in SCI has a long history,” he said, “so I think that, given even the minimal animal experimentation we have, it is reasonable to discuss moving to a clinical trial. This type of prophylactic treatment could lead to faster clinical recovery for certain high-risk spinal deformity surgery patients.”

Dr. Errico’s coauthors are Martin Quirno, MD; Kirk A. Campbell, MD; Andrew Yoo, BA; Ying Zhang, MD; and Thorsten Kirsch, PhD. Disclosure information: Dr. Errico—K2M, DePuy, Orthocon, Paradigm Spine, Elsevier. Drs. Quirno, Campbell, Zhang, and Kirsch, and Mr. Yoo reported no conflicts.