Evaluation of the efficacy of subcutaneous carbon dioxide insufflations for treating acute non specific neck pain in general practice: A sham controlled randomized trial.

Background: Subcutaneous carbon dioxide insufflations are a safe and inexpensive treatment modality in complementary medicine and are used mainly in musculoskeletal pain and vascular conditions. However, no rigorous trial exists on their efficacy.

Aims: To evaluate whether patients with acute non specific neck pain get pain free sooner, if treated with subcutaneous carbon dioxide insufflations compared to sham ultrasound.

Methods: One hundred and twenty-six persons from one German general practice with acute non specific neck pain less than 7 days and a current pain intensity 40 mm on a 100 mm visual analogue scale were included into the trial. Participants received either a maximum number of nine subcutaneous carbon dioxide insufflations or a maximum number of nine sham ultrasound administered by four therapists in a randomized order, thrice weekly. Main outcome measure was time to neck pain relief during a 28 days follow-up period from baseline analyzed by intention to treat.

Results: Twenty-seven of 63 patients (43%) got neck pain free in the subcutaneous carbon dioxide insufflations group compared to 29 of 63 (46%) in the sham ultrasound group. Median time to neck pain relief was 28 days in both groups (p=.77; logrank test). Secondary analyses yielded similar results.

Conclusions: The study indicates that subcutaneous carbon dioxide insufflations are not superior to sham ultrasound for treating patients with acute non specific neck pain. Because course of pain did not differ from the one expected from self limitation, it is likely that non specific effects played only a minor role, if any, in both interventions.