Study objectives: Pilot study comparing the short-term efficacy on pain and functional impairment of nerve root sheath versus interspinous glucocorticoid injections in patients admitted to a French rheumatology department for disk-related sciatica or femoral neuralgia.
Patients and methods: Thirty patients with refractory nerve root pain (sciatica, n = 29; femoral neuralgia, n = 1) for a mean of four months were randomized to nerve root injection (n = 17) or interspinous injection (n = 13) of the same mixture of 0.10 g of lidocaine hydrochloride and 3.75 mg of cortivazol. Both injection methods were performed under analgesia and benzodiazepine sedation to maintain double blinding. Each patient was evaluated daily during the first seven days of bed rest in the hospital, then after discharge on postinjection day 28.
Results: Prompt pain relief was obtained in both groups. On day 1, the mean pain scale score (0-100) fell from 70 +/- 3.9 to 26 +/- 5.6 in the nerve root group and from 63 +/- 4 to 23 +/- 4.7 in the interspinous group. These results were sustained on D7 and D28.
Conclusions: The unusually high level of efficacy of glucocorticoid injection in our study may be ascribable in part to strong placebo and Hawthorne effects and in part to the intrinsic effects of the injections. Whether nerve root injection is superior over interspinous injection remains unproven.