Clinical trials evaluating the use of methylprednisolone in the management of spinal cord injuries have studied various dosage regimens. One of the first clinical trials, the National Acute Spinal Cord Injury Study (NASCIS 1, published in 1984), compared methylprednisolone given as a 100 mg bolus followed by 25 mg every 6 hours for 10 days versus 1,000 mg bolus followed by 250 mg every 6 hours for 10 days. No difference in observed improvements occurred between the high- and low-dose groups, but there was a significantly increased incidence of wound infections in the high-dose group (9.3% vs. 2.6%) as well as a slightly higher incidence of sepsis, pulmonary embolism, and death within 14 days. In the subsequent trial (NASCIS II, published in 1990), patients received methylprednisolone as a 30 mg/kg bolus followed by 5.4 mg/kg for 23 hours, which was found to produce similar effects on motor and sensory scores compared to naloxone 5.4 mg/kg bolus followed by 0.5 mg/kg/h for 23 hours and placebo. [1], [2], [3]
Trials following NASCIS II utilized the same methylprednisolone dosage regimen, except for the NASCIS III trial in 1997 which compared methylprednisolone regimens of 5.4 mg/kg/h for 24 hours and 5.4 mg/kg/h for 48 hours. Expert opinion recommends that although high-dose steroid treatment may be safe in other patient populations, caution should be exercised in the setting of acute traumatic spinal cord injury given the data from NASCIS. It should be noted that none of the described studies specifically evaluate patients with cauda equina syndrome, and in fact, two studies excluded such patients. It is unknown if the dosage regimens utilized in the described studies would be effective and safe in the setting of cauda equina syndrome. [1,4-6]
A 2004 case series evaluated 63 patients diagnosed with schistosomal myeloradiculopathy (SMR) over a period spanning 15 years at a university hospital in Brazil; 12 (19%) patients had cone and cauda equina syndrome. Laboratory findings revealed abnormal CSF profiles in 93.7% of patients, frequently characterized by elevated protein concentrations and pleocytosis, with eosinophils detected in approximately 57% of samples. Treatment involved high-dose corticosteroids (prednisone or methylprednisolone 500 mg q12h for 5 days followed by prednisone) initiated within 24 hours of admission, followed by praziquantel therapy after confirmation of active schistosomiasis. The therapeutic response was rapid, with improvement frequently observed within 48 hours of corticosteroid initiation. Favorable neurological outcomes, ranging from full recovery to partial recovery without functional limitations, were achieved in 60.3% of patients. However, 39.7% experienced persistent functional impairments, correlating with more pronounced medullary involvement. All (100%) of the patients with cauda equina syndrome demonstrated complete recovery, which was significantly better than patients with meduallary forms (p= 0.007). Of note, the route of administration for methylprednisolone was not provided in the article. [7]
A 2002 experimental study investigated the efficacy of methylprednisolone in mitigating neurophysiological and histopathological damage in acute cauda equina injuries using a rabbit model. The study induced injury by applying an aneurysm clip with a closed pressure of 192 grams to the cauda equina at the S2–S3 level for three minutes, taking care to preserve the dura. Neurophysiological assessment involved measuring nerve conduction velocity (NCV) pre-injury, immediately post-injury, and three weeks after injury, while histopathological features were examined in excised tissue samples stained with hematoxylin-eosin. Rabbits were divided into four groups: three treatment groups receiving methylprednisolone (30 mg/kg) at 8, 16, or 24 hours post-injury alongside continuous infusion for 24 hours, and an untreated control group. Results demonstrated a statistically significant recovery in NCV at three weeks in the group treated at 8 hours post-injury (p<0.05), while improvements in the 16- and 24-hour treatment groups were less pronounced. Untreated animals exhibited no recovery. Histological analysis revealed minimal edema, inflammation, and hemorrhage in the 8-hour treatment group, contrasting with more pronounced pathological changes in later-treated or untreated groups. These findings underscore the importance of early methylprednisolone administration in limiting the progression of secondary injury mechanisms, such as edema and inflammation, which compromise nerve root function. The evidence supports the neuroprotective effects of high-dose corticosteroids administered within a critical time window following acute cauda equina injury. [8]