Identification of Epidural Space: A Comparison Study Between Contrast Spread and Loss of Resistance Techniques

The study participants were patients of Astoria Pain Management, New York, USA (age 28-72 years) with a clinical diagnosis of cervical radiculitis. The Canadian SHIELD Ethics Review Board approved this study (July 18, 2019. REB tracking number: 19-06-002), conducted from August 19, 2019, to October 8, 2019. There was no funding for this study. Patients were eligible for the study if they met the criteria for cervical ESI, which included clinical and recent MRI findings confirming the diagnosis of cervical radiculitis and inadequate pain relief with conservative care for more than 3 months. Other criteria were if the procedure was covered by medical insurance, and if they signed informed consent. Patients were excluded from the study if they were taking anticoagulants or had serious comorbidities such as congestive heart failure.

The patients were divided into two groups of 20 each and underwent CESI with either an 18G or a 25G Tuohy needle. The skin was anesthetized with 1% lidocaine in the 18G group but not in the 25G group. All cervical epidurals were performed utilizing the fluoroscopy only method when the needle was navigated from the skin toward the epidural space under contralateral oblique fluoroscopy [3], and the contrast spread technique [4,5] was employed for epidural space identification. After radiological confirmation of the epidural spread, LOR was tested using an Epidrum® device (Exmoor Innovations Ltd., Somerset, UK). I utilized the Epidrum device as I consider it a more objective and reproducible method for epidural space identification independent of the provider's skill with the LORT, and because its success rate is comparable to the results attained by trained anesthesiologists employing the LOR syringe [6, 7, 8]. Subsequently, accompanied by the radiology assistant, I observed the Epidrum for 30 seconds or more; if the Epidrum deflated, the result was positive. However, if the device remained inflated, the result was reported as negative. The collected data was then analyzed.