Revolutionizing the Loss-of-Resistance Technique

Approximately 2,400,000 epidurals and 700,000 epidural steroid injections are performed in the United States every year(1). For example, 70% of women in the US receive an epidural for pain management during labor(2). The utilization of lumbar epidural steroid injections to manage low back and leg pain (i.e., sciatica) is increasing, with Medicare spending for lumbar epidural procedures exceeding $175 million annually(3).

Before inserting an epidural catheter, a physician must first access the epidural space.This is accomplished by inserting a large needle into the patients back, guiding the needle blindly through a tough ligament, and relying on a loss of resistance to identify the very small epidural space, which is about as wide as a grain of rice is long. Unfortunately, tactile feedback is imperfect and physicians often miss the target area and accidently enter the back muscles or advance the needle too far and enter the spinal canal (dural puncture). Because the blind procedure is so difficult, there are two very common complications:

1. Debilitating headache resulting from dural puncture: 1 in 20 procedures(4-11)
2. Failed anesthesia resulting from incorrect catheter placement: 1 in 10 procedures(11-13)

Both of these complications lead to additional procedures, extended hospital stays, and increase the risk for the patient. In the case of a new mother, this preventable medical error couldn’t happen at a worse time. Both errors result in a considerable financial and workload burden for the hospital and the doctors. A measurement of the pressure can be used to confirm correct epidural needle and catheter placement and possibly avoid some of the common complications that occur during epidural anesthesia(14). For example, a recent report in the literature found, in 13 patients, that pressure transduction in the epidural space through a correctly positioned epidural catheter showed a pressure waveform which correlated with x-ray verified epidural catheter placement(15).

The Compassâ„¢ Epidural Assist will serve both the epidural anesthesia and epidural steroid injection markets.