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An Evaluation of Medications Commonly Used for Epidural Neurolysis Procedures in a Human Fibroblast Cell Culture Model
  1. Christof Birkenmaier, MD,
  2. Julia Redeker,
  3. Birte Sievers, PhD,
  4. Carolin Melcher, MD,
  5. Volkmar Jansson, MD and
  6. Susanne Mayer-Wagner, MD, PhD
  1. From the Department of Orthopedic Surgery, Grosshadern Medical Center, University of Munich, Marchioninistr., Munich, Germany.
  1. Address correspondence to: Christof Birkenmaier, MD, Department of Orthopedic Surgery, Grosshadern Medical Center, University of Munich, Marchioninistr. 15, 81377 Munich, Germany (e-mail: christof.birkenmaier{at}


Background and Objectives: Epidural injections are popular therapies for sciatica and low back pain. Local anesthetics and corticosteroids are commonly used for most injections techniques, but some treatments use a specific combination of several agents. The epidural lysis of adhesions procedure (Racz) uses a combination of bupivacaine, hyaluronidase, a corticosteroid, and hypertonic saline. Because severe complications, some with permanent neurologic deficits, have been observed, we considered the possibility that individual agents or a combination thereof might be capable of damaging or destroying cells in primarily the epidural tissues.

Methods: We used monolayer cell cultures of human fibroblasts in Dulbecco modified Eagle medium to study these pharmacological agents alone or in combination. Cell viability and proliferation were assessed by Trypan blue staining, cell counts, and the WST-1 assay. Time and concentration series were performed.

Results: With the corticosteroid, we observed the previously described proliferation-retarding effects. Hyaluronidase was not found to have a relevant effect on fibroblast proliferation. Bupivacaine and hypertonic saline were found to have a time- and concentration-dependent effect on cell viability and proliferation. Both were found to be toxic at concentrations well below the ones used clinically.

Conclusions: We identified a potential for harm caused by commonly used pharmacological agents when applied epidurally. Animal studies will have to show whether the same can be observed in living tissues.

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  • This study was supported by a research grant of the B. Braun Foundation, Melsungen, Germany.

  • Initial parts of this work have been presented at the 2008 Orthopedic Research Society Annual Meeting, San Francisco (poster presentation) and at the 2009 International Society for Minimal Intervention in Spinal Surgery Course, Zurich (podium presentation).