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©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
3T magnetic resonance neurography of pudendal nerve with cadaveric dissection correlation
Avneesh Chhabra, Courtney A McKenna, Vibhor Wadhwa, Gaurav K Thawait, John A Carrino, Gary P Lees, A Lee Dellon
Avneesh Chhabra, Musculoskeletal Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
Avneesh Chhabra, Vibhor Wadhwa, Gaurav K Thawait, John A Carrino, the Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
Courtney A McKenna, Gary P Lees, Department of Art As Applied to Medicine, Johns Hopkins University, Baltimore, MD 21205, United States
Vibhor Wadhwa, Department of Radiology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
John A Carrino, Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY 10021, United States
A Lee Dellon, Department of Plastic Surgery and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
Author contributions: Chhabra A, Carrino JA, Lees GP and Dellon AL contributed to study conception and design; McKenna CA, Wadhwa V, Thawait GK contributed to data acquisition, data interpretation, and writing of article; Chhabra A, McKenna CA, Wadhwa V, Thawait GK, Carrino JA, Lees GP, Dellon AL contributed to editing, reviewing and final approval of article.
Institutional review board statement: Institutional review board approval was taken for this observational study.
Informed consent statement: Informed consent was not required for this study.
Conflict-of-interest statement: Dr. Avneesh Chhabra received research grants from GE-AUR (GERRAF), Siemens; Medical Solutions and Integra Life Sciences. He also serves as a research consultant with Siemens CAD group; Dr. John A Carrino received patient research grants from Siemens and serves as a speaker for Siemens lectures.
Data sharing statement: No additional data is available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Avneesh Chhabra, MD, Adjunct faculty Johns Hopkins University, Associate Professor of Radiology and Orthopedic Surgery, Section Chief, Musculoskeletal Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, United States. avneesh.chhabra@utsouthwestern.edu
Telephone: +1-214-6482122
Received: February 15, 2016
Peer-review started: February 16, 2016
First decision: March 23, 2016
Revised: March 31, 2016
Accepted: May 10, 2016
Article in press: May 11, 2016
Published online: July 28, 2016
AIM: To evaluate the pudendal nerve segments that could be identified on magnetic resonance neurography (MRN) before and after surgical marking of different nerve segments.
METHODS: The hypothesis for this study was that pudendal nerve and its branches would be more easily seen after the surgical nerve marking. Institutional board approval was obtained. One male and one female cadaver pelvis were obtained from the anatomy board and were scanned using 3 Tesla MRI scanner using MR neurography sequences. All possible pudendal nerve branches were identified. The cadavers were then sent to the autopsy lab and were surgically dissected by a peripheral nerve surgeon and an anatomist to identify the pudendal nerve branches. Radiological markers were placed along the course of the pudendal nerve and its branches. The cadavers were then closed and rescanned using the same MRN protocol as the pre-marking scan. The remaining pudendal nerve branches were attempted to be identified using the radiological markers. All scans were read by an experienced musculoskeletal radiologist.
RESULTS: The pre-marking MR Neurography scans clearly showed the pudendal nerve at its exit from the lumbosacral plexus in the sciatic notch, at the level of the ischial spine and in the Alcock’s Canal in both cadavers. Additionally, the right hemorrhoidal branch could be identified in the male pelvis cadaver. The perineal and distal genital branches could not be identified. On post-marking scans, the markers were used as identifiable structures. The location of the perineal branch, the hemorroidal branch and the dorsal nerve to penis (in male cadaver)/clitoris (in female cadaver) could be seen. However, the visualization of these branches was suboptimal. The contralateral corresponding nerves were poorly seen despite marking on the surgical side. The nerve was best seen on axial T1W and T2W SPAIR images. The proximal segment could be seen well on 3D DW PSIF sequence. T2W SPACE was not very useful in visualization of this small nerve or its branches.
CONCLUSION: Proximal pudendal nerve is easily seen on MR neurography, however it is not possible to identify distal branches of the pudendal nerve even after surgical marking.
Core tip: The radiologist should comment on lesions detected on magnetic resonance neurography along the course of the pudendal branch nerves or their approximate location, that could be helpful in image guided pain injections directed at the distal branches. However, they should not over-diagnose pudendal branch neuropathy or avoid mistaking the nearby vessels as distal pudendal branches.
