Bacteriostatic Normal Saline Versus Lidocaine for Intradermal Anesthesia During Lumbar Medial Branch Block

Most chronic pain procedures or injections utilize medications (e.g. local anesthetics) to numb the skin in an effort to reduce procedure-related pain; however, they can also be a significant cause of pain leading the patient to abort the procedure. Studies have looked at alternative medications and techniques that lessen the pain but still provide similar levels of anesthesia ("numbing"). One such alternative medication is normal saline that includes benzyl alcohol. Studies researching this specific medication have usually examined procedural pain related to drawing blood or placing an intravenous (IV) catheter but not for chronic pain related procedures.

This is a single site randomized double-blinded clinical trial that will compare the standard of care (1% lidocaine) with bacteriostatic normal saline (saline with benzyl alcohol) administered as a skin wheal during a diagnostic procedure in patients with chronic low back pain. The order of administration of the medication will be randomized and the medication will be blinded to both the subject and the investigator performing the procedure. Skin wheals will be created with each medication, and the subject's level of pain will be assessed after each one to measure how painful the creation of the skin wheal was. Then, a spinal needle for the diagnostic procedure will be placed through the skin wheal and the subject's level of pain will be assessed after each one to measure the level of anesthesia (or numbing) that each one provides. The objectives of this study are to determine if administration of bacteriostatic normal saline causes less discomfort than 1% lidocaine and provides a similar level of anesthesia/numbing for the procedure.

The study will take place at the Grady Pain clinic and participants will be identified from patients that are scheduled to undergo a specific low back procedure - diagnostic lumbar medial branch block. This research study will help identify potential alternatives to the standard of care for numbing of skin during chronic pain procedures that may reduce procedure-related pain and discomfort thus making the procedure more tolerable.