Analysis of epidural waveform for cervical epidural steroid injections confirmed with fluoroscopy

Abstract

The identification of epidural space with loss of resistance (LOR) is commonly performed. But it lacks specificity. Epidural pressure waveform analysis (EPWA) provides a simple confirmative adjunct for LOR. If the needle is located within the epidural space, measurement of the pressure at its tips shows a pulsatile waveform. Previous studies demonstrated satisfactory sensitivity and specificity of EPWA. However, success or failure of epidural injection was confirmed by the pinprick test, which is limited for patients in the setting of the pain clinic. In this study, we evaluated the sensitivity, specificity, as well as positive and negative predictive values of EPWA for cervical epidural steroid injection (CESI) confirmed by fluoroscopy.One hundred and five CESIs of 75 patients suffering from neck and radicular arm pain of over 3 months duration were enrolled. The physician injected 5 mL of normal saline after a feeling of satisfactory LOR. Saline filled extension tubing, connected to a pressure transducer, was attached to the needle. A 3 mL bolus of contrast medium was injected to confirm the success of CESI.The incorrect identification of epidural space with LOR (false LOR) was 29.5%. Of these 31 failed CESIs, 2 showed epidural waveform and 29 did not. The sensitivity, specificity, positive and negative predictive value of EPWA was 94.5%, 93.5%, 97.2%, and 87.7%, respectively.EPWA shows satisfactory reliability and is a simple adjunct to decrease false LOR for CESI. Further confirmative studies are required before its routine use in clinical practice.

Analysis of Epidural Waveform to Determine Correct Epidural Catheter Placement After CSE Labor Analgesia

“…However, with repeated observations and experience, the weak pulsatile waveforms can also be clearly identified. Indeed, in a previous paper which used a standard pressure transducer, 12 50% of patients had epidural waveform of weak oscillation, whereas in our cases the majority of the oscillations were mainly strong and easily evident, and in only 15% the waveforms were weak. However, previous studies were performed with commercially available blood pressure transducers not specifically designed for the epidural use, and therefore less sensitive to the epidural signal.…”

Contralateral oblique view can prevent dural puncture in fluoroscopy-guided cervical epidural access: a prospective observational study

“…Gaps in the ligamentum flavum and paravertebral muscles (including cysts and fascial planes) may lead to false-positive LOR. Contrast is usually administered during these situations, which may blur bony landmarks and needle tips 19 21. The incidence of false-positive LOR during cervical epidural injection using the lateral view was 20.5%–76.5% in previous studies; our previous study found this incidence of 20.6% 8 13 19 24.…”

“…In the 393 cervical interlaminar accesses, there was no dural puncture event though novice trainees were included as operators. The reported incidence of dural puncture in fluoroscopically guided cervical epidural procedures performed in the AP or lateral view was 1%–2% 9 10 21 22. Considering that spinal cord injury can cause permanent neurologic deficits,2 4 6 the aforementioned incidence rate is fairly high, as dural puncture may lead to spinal cord injury.…”

Confirmation of Epidural Catheter Location by Epidural Pressure Waveform Recordings by the Compuflo<sup>® </sup> Cath-Checker System

“…The presence of pulsatile waveforms have been well documented in cervical [5], thoracic [6] [7] [8] [9] [10] and lumbar epidural space, [8] [11] and high sensitivity to reliably identify the epidural space and correct epidural positioning of needle and catheter has been reported in many studies [12].…”