Transforaminal injection of steroids is effective only in a proportion of patients. Its superiority over other injections is obscured when group data are compared but emerges when categorical outcomes are calculated. Over time, the proportion of patients with maintained responses diminishes.

These results indicate that TFIS is more often successful in patients without significant compression of the nerve root and, therefore, in whom an inflammatory basis for radicular pain is most likely. In such patients, a success rate of 75% renders TFIS an attractive alternative to surgery. In patients with significant compression of the nerve root, the likelihood of benefiting from TFIS is low. The success rate may be no more than that of a placebo effect, and surgery may be a more appropriate consideration.

The results of this study support the role of endoscopic resection in the treatment of patients with colloid cysts as a safe and effective modality. In some cases, conversion to an open procedure may be required. Additional follow-up will be required to continue to address the duration of lesion-free survival.