The Effect of Midazolam Sedation on Diagnostic Medial Branch Blocks

This prospective observational study aims to investigate the effects of midazolam sedation on the diagnostic validity of lumbar medial branch blocks in patients diagnosed with lumbar spondylosis without myelopathy. Patients typically receive two subsequent diagnostic blocks prior RFTC, to ensure that the correct location has been targeted. When patients achieve at least 80% pain relief after both diagnostic blocks, this is considered a positive result and they can proceed to receive RFTC. If patients have positive diagnostic blocks but their RFTC is not successful, this is considered a false positive diagnostic result. This study will determine 1) if a higher number of sedated patients proceed to radiofrequency thermocoagulation (RFTC) than non-sedated patients, and 2) if there are a higher number of false positive results in sedated patients. The hypothesis is that the use of midazolam sedation will increase the number of patients who perceive to have pain relief from their diagnostic block results, resulting in more patients proceeding to RFTC, and that there will be a higher number of false positive results in sedated patients. The primary outcome measure is the number of sedated versus non-sedated patients that have positive block results. A positive result will be calculated by having at least one NRS score that is at least 80% lower than their baseline NRS score in the 8 hours following lumbar MBB. The secondary outcome will be the number of false positive blocks in sedated versus non-sedated patients. After patients achieve 80% relief after each of the two diagnostic lumbar medial branch blocks and proceeds with lumbar RFTC, we will then collect NRS scores 24 hours after both diagnostic Lumbar MBB, and 4 weeks and at 8 weeks after the lumbar RFTC. If a patient has not received at least 50% reduction from their baseline NRS score by 8 weeks, this will be considered a false positive. A 7-point Patient Global Impression of Change (PGIC) score 8 hours after each Lumbar MBB will also be collected, and at 4 weeks and 8 weeks after the lumbar RFTC, and any adverse effects patients experience. In addition, Oswestry Disability Index (ODI) will be collected at 4 and 8 weeks after lumbar RFTC. The results of this study will help guide the use of sedation when performing diagnostic blocks on patients with lumbar spondylosis, in order to reduce the number of false positive blocks.

Inclusion criteria

• Adult patients at least 18 years of age
• History of axial low back pain for at least 3 months
• Indication for bilateral lumbar medial branch block (L3, L4, L5 medial branch nerves)
• Diagnosis of Lumbar Spondylosis without Myelopathy >4/10 pain on a 0-10 numerical rating scale (NRS)

Exclusion criteria

• Low back pain with radiculopathy symptoms (this is a diagnosis of sciatica and treatment is not with lumbar medial branch block)
• Uncontrolled major depression or other mental health issues causing instability
• Pregnant or lactating women
• <18 years old
• History of adverse reaction to either midazolam, lidocaine, or bupivacaine
• Focal neurological deficits, cognitive impairments, or memory issues
• Non-English speaking
• Hearing impaired that are unable to understand verbal instructions
• Active Infection
• On Anticoagulation or Antiplatelet Therapy
• History of Clotting Disorder
• Previous Lumbar Medial Branch Block and/or Lumbar Radiofrequency Ablation