[Jan. 22, 2023: Elise Castelli, Society of Interventional Radiology]
Damaged nerves can be regenerated with the application of a frozen needle under advanced imaging guidance. (CREDIT: Creative Commons)
Damaged nerves can be regenerated with the application of a frozen needle under advanced imaging guidance, according to new research to be presented at the Society of Interventional Radiology Annual Scientific Meeting in Boston.
The technique, called interventional cryoneurolysis, is performed by an interventional radiologist and can offer hope to patients in persistent pain following a traumatic injury.
“The idea that we can induce regeneration of damaged nerves simply by placing a cold needle through the skin under imaging guidance is extremely exciting,” said the lead author of the study, J. David Prologo, MD, FSIR, ABOM-D, an interventional radiologist and associate professor at Emory University School of Medicine in Atlanta. “This research answers the call from United States legislators and specialty medical societies to develop alternatives to opioids for the management of pain.”
Researchers at Emory University treated eight patients with chronic nerve pain related to a prior trauma with CT-guided interventional cryoneurolysis. CT-guided cryoneurolysis uses imaging to place a needle and freeze damaged nerves, causing them to degenerate and lose function.
"What happens next is almost magical,” Prologo says. “If the nerve is exposed to the correct amount of cold, over the correct area, for the right amount of time, it will regenerate—replacing the previously damaged nerve with a healthy one.”
In this study, the average time from traumatic injury to the procedure was 9.5 years. There were no procedure related complications or adverse events, and all patients returned to their baseline strength over time—confirming regeneration of the targeted nerve. In six of the eight patients, pain symptoms dramatically improved following regeneration—reflected as a collective decrease of 4.6 points in Visual Analog Scale pain scores.
Prologo believes that the interventional radiology skillset applied to nerve freezing has many applications for treatment of complex pain.
Cryoneurolysis: How I Do It. (CREDIT: J. David Prologo, MD, FSIR, ABOM-D)
“We are using this regeneration technique not only to manage nerve pain induced by trauma—but also for pudendal neuralgia, post mastectomy pain, post-surgical pain, and many other conditions historically managed with narcotics,” says Prologo.
“Interventional radiologists can place these needles safely in precise locations all over the body, allowing access to pain generators that were previously unreachable and giving hope to patients who struggle with pain.”
What is the Visual Analogue Pain Scale?
A Visual Analogue Scale (VAS) is one of the pain rating scales used for the first time in 1921 by Hayes and Patterson. It is often used in epidemiologic and clinical research to measure the intensity or frequency of various symptoms.
For example, the amount of pain that a patient feels ranges across a continuum from none to an extreme amount of pain. From the patient's perspective, this spectrum appears continuous ± their pain does not take discrete jumps, as a categorization of none, mild, moderate and severe would suggest. It was to capture this idea of an underlying continuum that the VAS was devised.
Purpose of the scale
The pain VAS is a unidimensional measure of pain intensity, used to record patients’ pain progression, or compare pain severity between paints with similar conditions. VAS has been widely used in diverse adult populations for example; those with rheumatic diseases, patients with chronic pain, cancer, or cases with allergic rhinitis. In addition to rating pain, it has been used to evaluate mood, appetite, asthma, dyspepsia, and ambulation, and it can be used as a simple, valid, and effective to assess disease control.
VAS can be presented in a number of ways, including:
Numerical rating scales, scales with a middle point, graduations, or numbers.
Curvilinear analog scales, meter-shaped scales.
"Box-scales" consist of circles equidistant from each other (one of which the subject has to mark).
Graphic rating scales or Likert scales with descriptive terms at intervals along a line.
The most simple VAS is a straight horizontal line of fixed length, usually 100 mm. The ends are defined as the extreme limits of the parameter to be measured (symptom, pain, health) orientated from the left (worst) to the right (best). In some studies, horizontal scales are orientated from right to left, and many investigators use vertical VAS.
No difference between horizontal and vertical VAS has been shown in a survey involving 100 subjects but other authors have suggested that the two orientations differ with regard to the number of possible angles of view. Reproducibility has been shown to vary along 100-mm and along a horizontal VAS. the choice of terms to define the anchors of a scale has also been described as important.
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Note: Materials provided by Society of Interventional Radiology. Content may be edited for style and length.
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