Intrathecal Steroids to Provide Pain Relief in Clients Experiencing PHN

Traditionally, Epidural Steroid Injections (ESI) have been recommended for early use in a client experiencing acute herpes zoster to prevent the development of postherpetic neuralgia (PHN). Current evidence now supports the use of intrathecal steroids to provide pain relief in clients experiencing PHN (Benzon H, Chekka K, Darnule A, et al., 2009).

Studies conducted by Owlia et al., concluded that a 40 mg dose of a corticosteriod know as methylprednisolone achieved greater pain relief effects and fewer adverse effects than were achieved with a 80 mg dose(Owalia M, Salimzadeh A, Alishiri G, Haghighi A, 2007).

An additional randomized, double-blind study conducted by Kang et al., that evaluated the effects of steroid dosing during TF ESI, found no difference in the level of benefits experienced by clients receiving 10, 20 and 40 mg doses of the corticosteroid triamcinolone; A 5 mg dose failed to produce the same benefits (Kang S, Hwang B, Son H, et al., 2011).

Furthermore, a randomized study conducted by Revel et al., found that when a steroid was injected in a 40 ml volume of saline it provided superior pain relief for a client than when the same dose of steroid was injected independently of the 40 ml volume of saline in an 18 month follow-up with the same clients (Revel M, Auleley g, Alaoui S, et al., 1996).

In the past it had been reported in the literature that depo-medrol or intrathecal methylprednisolone acetate (MPA), when injected intrathecally during an ESI procedure, could use polyethylene glycol as a vehicle to initiate an inflammatory response in the body, causing arachnoiditis (Kotani N, Kushikata T, Hasimoto H, et al., 2000). However a recent study that used MPA for treatment of PHN failed to produce evidence of either aspect meningitis or arachnoiditis in 89 patients who had been treated with 4, 60 mg injections. Patients in this study underwent diagnostic lumbar punctures and magnetic resonance imaging for a two year follow up period (Kotani N, Kushikata T, Hasimoto H, et al., 2000).

It has been reported that repeated steroid injections have been associated with Cushing syndrome and adrenal suppression in some patients. In susceptible patients it is unlikely this complication can be avoided even with only a single, relatively small steroid dose. For the general patient population, the general guiding principle to use for repeated steroid injections is to provide it only to those patients who experience significant benefits from the procedure. Another guiding principle involves spacing the injections at long enough intervals to allow for complete recovery of adrenal function. If a patient is undergoing surgery within a few weeks of receiving a depo-steroid injection, best practice would include an evaluation of this patient for adrenal suppression and they should receive stress steroid coverage during the perioperative period.

Studies report that the chance of traumatic spinal cord injury due to needle trauma is increased in a client who receives sedation or general anaesthesia during an epidural injection, especially those who were unresponsive during the treatment (Rathmell et al., 2011). We can use the results of these studies to influence what a patient is offered during an epidural injection, rather then sedation or general anaesthesia, a client should be offered anxiolytics to reduce the chance of tramautic spinal cord injuries in patients receiving an ESI.

The number of epidural injections required to achieve optimal pain relief is not specified in the literature as of yet, however from experience, and through reviews of the literature available, it appears that the ideal approach for epidural injections would be 2 injections, 2 weeks apart, using no more than a 40 mg dose of steroid for the injection, although each dose would be personalized to the patient by the doctor.

When considering whether a patient should discontinue their use of anticoagulants before an ESI, one must recognize that discontinuing anticoagulants can actually cause 3x more complications then complications that may arise from bleeding during the procedure. A safe option for practitioners to consider would involve conducting a caudal before an ESI and, if safe, continuing with the patients usual anticoagulant schedule to prevent adverse effects associated with discontinuation.

References:
Benzon H, Chekka K, Darnule A, et al. Evidence-based case report: the prevention and management of postherpetic neuralgia with emphasis on interventional procedures. Reg Anesth Pain Med. 2009;34:514Y521.
Kang S, Hwang B, Son H, et al. The dosages of corticosteroid in transforaminal epidural steroid injections for lumbar radicular pain due to a herniated disc. Pain Physician. 2011;14:361Y370.
Kotani N, Kushikata T, Hashimoto H, et al. Intrathecal methylprednisolone for intractable postherpetic neuralgia. N Engl J Med. 2000;343:1514Y1519.
Owlia M, Salimzadeh A, Alishiri G, Haghighi A. Comparison of two doses of corticosteroid in epidural steroid injection for lumbar radicular pain. Singapore Med J. 2007;48:241Y245.
Rathmell J, Michna E, Fitzgibbon D, et al. Injury and liability associated with cervical procedures for chronic pain. Anesthesiology. 2011;114:918Y926.
Revel M,AuleleyG,AlaouiS,etal.Forcefulepiduralinjectionsforthe treatment of lumbosciatic pain with post-operative lumbar spinal fibrosis. Rev Rhum Engl Ed. 1996;63:270Y277.