Lumbar foraminal injection under fluoroscopic guidance is indicated either for a diagnostic purpose to determine which nerve root is painful or for a selective steroid injection. Lumbar foraminal approach is based on that of the posterolateral extradural diskography. Selective puncture of the first sacral foramen under fluoroscopic guidance may be indicated for the treatment of sacral symptomatic meningeal cysts, a very unfrequent lesion.