Comment on the Evaluation of the Effectiveness of Hyaluronidase in the Selective Nerve Root Block of Radiculopathy.

Dear Editor,

Ko et al. [1] provided valuable information in a double-blind, randomized, controlled clinical trial that assessed the effectiveness of hyaluronidase in selective nerve root block for radiculopathy. They included 126 patients in each group that receiving hyaluronidase or local anesthetic and steroids without hyaluronidase. A transforaminal epidural injection with a particulate steroid, along with hyaluronidase was done. Even though the results were reportedly superior in the hyaluronidase group, the follow-up was short and the proportion of patients with significant improvement was not reported. The authors discussed the adverse consequences of hyaluronidase but did not discuss the adverse consequences of particulate steroids and transforaminal epidural injections [23]. Short-term follow-up data are difficult to interpret in spine management. More recently, clinical investigators have ruled out short-term follow-ups as not being decisive, yet have utilized them to show the lack of effectiveness of interventions [45]. Consequently, the efficacy and superiority of transforaminal epidural injections continues to be debated [678].

The authors described that selective nerve root blocks routinely provided short-term relief. They also referenced studies reporting that selective nerve root blocks in patients with herniated intervertebral discs were effective after 2 weeks, but did not have a lasting effect [910]. Neither of the cited studies included selective nerve root blocks as part of their trials. Rather they studied interlaminar epidural injections.

Thus, the authors may want to look at various issues related to transforaminal epidural injections with its adverse consequences and recent warnings of particulate steroids, alternate techniques, and long-term outcomes of transforaminal epidural injections. It will be interesting to see if hyaluronidase is any more effective than steroids or local anesthetic alone on a long-term basis. If a methodology of at least one year had been utilized, this important research would have had greater strength and value to the medical community.