Featured Research

from universities, journals, and other organizations

Ultrasound guided pudendal nerve block: A cadaveric study

Date:
March 6, 2014
Source:
American Academy of Pain Medicine (AAPM)
Summary:
The spread of close to 80% of injectate to surrounding soft tissues following a nerve block to treat chronic pelvic pain suggests a need to reduce the quantity injected, according to a new study.

The spread of close to 80% of injectate to surrounding soft tissues following a nerve block to treat chronic pelvic pain suggests a need to reduce the quantity injected, according to study authors, who presented results in a scientific poster today at the 30th Annual Meeting of the American Academy of Pain Medicine.

Though needles were accurately placed during ultrasound-guided pudendal nerve block (PNB) in a cadaver study, results show only 20% of the injectate was found in the interligamentous space, which was the target site. This type of finding has gone largely unexplored in the previous literature, the researchers said.

Lead study author Yuexiang Wang, MD, of the Mayo Clinic's Department of Anesthesiology in Rochester, Minn., said 4-5 mL of injectate is the most commonly used volume in PNB, either guided by fluoroscopy, computed tomography (CT) or ultrasound.

"Although favorable clinical results have been reported by using this amount of injectate, unintended sciatic nerve block is not a rare complication," Dr. Wang said. "Thus, it is unclear as to whether 4 mL, while being effective in blocking the nerve, may be too much volume for the space into which it is being injected."

The investigators searched previous studies and found none addressing the spread pattern of 4 mL injectate under ultrasound guidance, although the spread pattern of a larger amount of injectate (10 mL) was reported (Prat-Pradal et al, Surg Radiol Anat 2009; 31(4):289-93). They decided to study the spread of 4 mL injectate at the level of the ischial spine to better understand what the appropriate volume might be.

For the study, investigators performed PNB bilaterally in 2 cadavers. Guided by ultrasound via a 5 MHz curvilinear transducer, they injected 4 mL of iodine-based contrast into the space between the sacrotuberous ligament and sacrospinous ligament, just medial to the ischial spine.

Using cone-beam CT to assess the spread, investigators observed contrast had spread to the following areas:

• The perirectal fat in 3 injections

• Alcock's canal in 2 injections

• The gluteus maximus and piriformis muscles in 1 injection

No spread to surrounding blood vessels was observed.

Dr. Wang said the effects of the spread outside the interligamentous plane are unpredictable and could be beneficial or detrimental for clinical patients.

"On one hand, the spread of the contrast into the Alcock's canal and the perirectal fat space may cause additional blockage of the inferior rectal nerve, which arises from the pudendal nerve at the beginning of the pudendal canal, then enter the proximal part of the ischiorectal fossa in most cases," Dr. Wang said. "On the other hand, the spread into the gluteus maximus and piriformis muscle may cause an unintended sciatic nerve block which is considered a potential risk for PNB."

Ultrasound PNB has been shown to be effective in treating pudendal neuralgia, which is a common cause of chronic pelvic pain (Rofaeel et al, Reg Anesth Pain Med 2008;33(2):139-45). Using ultrasound to guide the procedure is touted by supporters as advantageous for clearly visualizing each anatomical landmark during treatment, thus increasing accuracy and avoiding the risk of unintended intravascular injection and sciatic nerve block.


Story Source:

The above story is based on materials provided by American Academy of Pain Medicine (AAPM). Note: Materials may be edited for content and length.


Cite This Page:

American Academy of Pain Medicine (AAPM). "Ultrasound guided pudendal nerve block: A cadaveric study." ScienceDaily. ScienceDaily, 6 March 2014. <www.sciencedaily.com/releases/2014/03/140306211036.htm>.
American Academy of Pain Medicine (AAPM). (2014, March 6). Ultrasound guided pudendal nerve block: A cadaveric study. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2014/03/140306211036.htm
American Academy of Pain Medicine (AAPM). "Ultrasound guided pudendal nerve block: A cadaveric study." ScienceDaily. www.sciencedaily.com/releases/2014/03/140306211036.htm (accessed October 20, 2014).

Share This



More Health & Medicine News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Microneedle Patch Promises Painless Pricks

Microneedle Patch Promises Painless Pricks

Reuters - Innovations Video Online (Oct. 18, 2014) Researchers at The National University of Singapore have invented a new microneedle patch that could offer a faster and less painful delivery of drugs such as insulin and painkillers. Video provided by Reuters
Powered by NewsLook.com
Raw: Nurse Nina Pham Arrives in Maryland

Raw: Nurse Nina Pham Arrives in Maryland

AP (Oct. 17, 2014) The first nurse to be diagnosed with Ebola at a Dallas hospital walked down the stairs of an executive jet into an ambulance at an airport in Frederick, Maryland, on Thursday. Pham will be treated at the National Institutes of Health. (Oct. 16) Video provided by AP
Powered by NewsLook.com
Raw: Cruise Ship Returns to US Over Ebola Fears

Raw: Cruise Ship Returns to US Over Ebola Fears

AP (Oct. 17, 2014) A Caribbean cruise ship carrying a Dallas health care worker who is being monitored for signs of the Ebola virus is heading back to Texas, US, after being refused permission to dock in Cozumel, Mexico. (Oct. 17) Video provided by AP
Powered by NewsLook.com
Spanish Govt: Four Suspected Ebola Cases in Spain Test Negative

Spanish Govt: Four Suspected Ebola Cases in Spain Test Negative

AFP (Oct. 17, 2014) All four suspected Ebola cases admitted to hospitals in Spain on Thursday have tested negative for the deadly virus in a first round of tests, the government said Friday. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins