Adjuvant hyaluronidase to epidural steroid improves the quality of analgesia in failed back surgery syndrome: a prospective randomized clinical trial.

Background: Management of low back pain after spinal surgeries is one of the most challenging problems in pain medicine. Transforaminal lumbar epidural steroid injection has been used with inconsistent response. Most patients require multiple and frequent injections due to high recurrence of back pain.

Objective: To find out whether the addition of hyaluronidase to the epidural injectate affects the quality and duration of analgesia in patients with low back pain secondary to failed back surgery syndrome.

Study Design: Prospective randomized trial.

Methods: The study was registered in the Government Clinical Trial registry and the protocol was reviewed and approved by the institutional review board. After obtaining an informed consent, 25 patients with low back pain due to failed back syndrome were randomly assigned to receive a transforaminal epidural injection of hyaluronidase 1500 IU (HYL) or normal saline (NSL) to a mixture of bupivacaine 0.5% (1 mL) and triamcinolone 40 mg (1 mL) in a double-blind fashion. An interventional pain specialist using fluoroscopic guidance performed all epidural injections. The patients received a comprehensive neurological examination by a non-interventional pain specialist who was blinded to the treatment during their follow-up visits, scheduled one, 2, and 4 weeks after the intervention. Numerical pain scores, analgesic requirement, and satisfaction scores were recorded during every visit.

Results: There was no difference in demographic data between the 2 groups. Pain scores and total analgesic requirement were significantly lower in the HYL group at 2 and 4 weeks after blockade (P < 0.01). Patient satisfaction was higher in the HYL group.

Limitations: The study was limited by a relatively small sample size.

Conclusion: We conclude that adding hyaluronidase to the epidural injectate was effective in the management of chronic low back pain in patients with failed back surgery syndrome demonstrated over a period of 4 weeks.