Percutaneous Neuroplasty for Chronic Low Back Pain with Hypertonic Saline: A Retrospective Analysis

Winston C.V. Parris, M.D., Ira Fox, M.D., Debbie Areford, R.N., Sheila Carver, R.N., Dan Thomas, M.D.
Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina

Introduction

Many patients with chronic low back pain secondary to spinal stenosis (SS) and Failed Back Surgery Syndrome (FBSS) do not respond to conventional pain modalities (eg., Epidural Steroid Injections and Lumbar Facet Injections. Percutaneous Neuroplasty (PN) with 10% Hypertonic Saline (HS) appears to be useful in managing pain in that patient population. The mechanism of action is not precisely known. It is proposed that HS may decrease neuronal swelling via osmotically-induced fluid shift, resulting in decreased pressure on nerves; HS may have a local anesthetic on intact dorsal rootlets; C-Fiber blockade secondary to the chloride effect of HS and possible to a diuretic on epidural scar tissue. A retrospective analysis of patients with intractable low back pain associated with SS and FBSS and who were treated with PN using 10% HS was performed for efficacy and safety.

Methods

After obtaining Institutional Review Board permission, 36 patients with chronic low back pain secondary to SS and FBSS, and who had failed to respond to conventional therapy including lumbar spine surgery, were treated with PN using 10% HS and Hyaluronidase. The HS was administered via a caudal epidural catheter, which was placed under fluoroscopic guidance while location (right or left) and vertebral level were confirmed using contrast media (Isovue – 300). Prior to HS injection, a test dose of 3 ml of 0.25% Bupivacaine was administered via epidural catheter intra-operatively using full aseptic technique. The patient was assessed neurologically 30 minutes later to determine the presence of motor function deficit, which would be indicative of intrathecal catheter placement. This situation would warrant catheter removal and termination of the PN. In patients without any motor deficit, 6 -10 ml of 10% HS was injected slowly via the caudal epidural catheter. Pain associated with the HS injection was short-lived (3 to 5 minutes) and effectively controlled with 50-150 mg Fentanyl administered intravenously.

Results

Using the sign test, the results show that PN was effective in decreasing pain in patients with SS and FBSS. The P value for 1 hour, 2 weeks and 4 weeks post procedure pain assessment was very small suggesting that the observed pain score result is unlikely due to chance. There were no adverse events. The median reduction in pain score was 3, 2, and 2 at 1 hour, 2 weeks, and 4 weeks, respectively. These differences were statistically significant at the p=0.001 level.

Conclusion

A retrospective analysis of patients with chronic low back pain secondary to SS and FBSS shows that Percutaneous Neuroplasty with 10% HS and Hyaluronidase is effective and safe in controlling pain. The relative analgesic contribution of HS and Hyaluronidase is not known. More scientific studies are required to determine the precise mechanism of action of HS and Hyaluronidase in relieving pain in patients with chronic low back pain and prospective and prospective, randomized, double-blind investigations are warranted to explore these preliminary findings.

Anesthesiology 2007; 107: A898

Presented at the October 2007 meeting of the American Society of Anesthesiologists.
[abstract available at www.asaabstracts.com]

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Published on site 7/26/08