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 40mg (1 mL) in a doubleblind 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.
Key words: Low back pain, lumbar epidural injection, steroid, hyalorunidase, bupivacaine