Relative to the number of procedures reported, the risk of complications remains very low. Short-term complications include bruising at the injection site, possible site-related pain, numbness in the distribution of the nerve being blocked, and sometimes neuritis, which can cause more pain temporarily after the procedure. Most of these complications are transient.

Catastrophic complications have also been described [20–25]. Therefore, the procedure should only be performed by those who have completed proper training. Complications are often related to the failure to recognize abnormal needle placement, failure to abort a procedure in the setting of patient intolerance, vascular penetration of the needle, and excessive sedation whereby the patient cannot respond. Depending on the location in the spine, vascular penetration has a relatively high incidence (11–19%); thus, recognition is paramount to procedural safety [26]. The use of particulate steroid has also been implicated as the cause of the spinal cord injury in the setting of vascular uptake. Nevertheless, even though vascular penetration occurs frequently, clinical sequelae are uncommon. In many settings, severe central, foraminal, or lateral recess stenosis is present; thereby, it is imperative to have the patient awake and responsive during the procedure as many catastrophic complications such as permanent nerve damage have been reported in this setting, most likely related to severe nerve ischemia.

There is a paucity of “level 1” evidence for the use of SNRB/TFESI for both diagnostic and therapeutic purposes. Level 1 implies randomized, prospective, double-blinded, placebo controlled outcome studies. Because pain is such a subjective experience, with a significant amount of patient-to-patient variability, it is a difficult measure to standardize. As such, most studies will include outcomes based on more objective measures such as ODI, quality of life measures, and avoidance of surgery. Since epidural steroid injections are performed so frequently, there are a plethora of opinions regarding their utility and place in the overall management of pain. SNRB/TFESIs frequently get grouped into all spinal interventions when meta-analyses are done, which includes interlaminar and caudal epidural steroid injections.

Recently, Chou et al. published a review in the Annals of Internal Medicine, which essentially concluded that there is no evidence to support the use of epidural steroid injections for the management of pain related to disk herniations [27]. This contradicts many studies published in both pain management and rehabilitation medicine journals [28–32]. Most of the specialty-specific articles agree that these procedures do work for the management of pain related to disk herniation s . There is more uncertainty as to how to perform them (interlaminar, caudal, or transforaminal), when to perform them, and how frequently they can or should be performed. Since the majority of these procedures are performed in the lumbar spine, the majority of the literature is relative to blocks performed in this region. There are retrospective reports of success in the cervical spine, which have been recently published by the Cleveland Clinic [33].

SNRB/TFESIs are a useful adjunct in the diagnosis and treatment of painful spinal conditions as outlined earlier. As with most procedures in medicine, success is related to patient selection as well as the use of a comprehensive management approach. Improvement in ODI, quality of life measures, and participation in a rehabilitation program are methods to monitor progress of patients with pain. A thorough evaluation of the patient should be performed prior to the procedure, ideally including an MRI unless contraindicated.

Image guidance should be utilized for all procedures. While fluoroscopy is the most frequently utilized, recent advances in ultrasound position it as potentially useful as well. The technique has to be adjusted in the setting of severe spine degeneration. Recognition of proper needle placement and more importantly improper needle placement are important to prevent catastrophic complications such as spinal cord injury. The risk of catastrophic complications is extremely low relative to surgery, assuming the patient has a normal coagulation status, there is absence of systemic or local infection, and proper technique is utilized. There is evidence to support the use of this procedure for the management of spine-related pain, and the potential benefit significantly outweighs the potential risk.