Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Apr 18, 2017; 8(4): 310-316
Published online Apr 18, 2017. doi: 10.5312/wjo.v8.i4.310
Posterior interosseous nerve localization within the proximal forearm - a patient normalized parameter
Srinath Kamineni, Crystal R Norgren, Evan M Davidson, Ellora P Kamineni, Andrew S Deane
Srinath Kamineni, Elbow Shoulder Research Centre, Department of Orthopaedics and Sports Medicine, University of Kentucky, Lexington, KY 40506, United States
Crystal R Norgren, Evan M Davidson, University of Kentucky College of Medicine, Lexington, KY 40506, United States
Ellora P Kamineni, Paul Laurence Dunbar High School, Lexington, KY 40513, United States
Andrew S Deane, Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, United States
Author contributions: Kamineni S and Deane AS designed the research; Kamineni S, Norgren CR and Davidson EM performed the research; Kamineni S and Kamineni EP analyzed the data; Kamineni S, Norgren CR, Kamineni EP and Davidson EM wrote the paper; all authors performed dissection.
Institutional review board statement: The study was exempt by the University of Kentucky Institutional Review Board, since it does not involve patients or clinical data.
Conflict-of-interest statement: None.
Data sharing statement: None.
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: Srinath Kamineni, MD, Elbow Shoulder Research Centre, Department of Orthopaedics and Sports Medicine, University of Kentucky, 740 South Limestone K412, Lexington, KY 40506, United States. srinathkamineni@gmail.com
Telephone: +1-859-2183057 Fax: +1-859-3232412
Received: April 3, 2016
Peer-review started: April 6, 2016
First decision: May 17, 2016
Revised: February 7, 2017
Accepted: February 28, 2017
Article in press: March 2, 2017
Published online: April 18, 2017
Abstract
AIM

To provide a “patient-normalized” parameter in the proximal forearm.

METHODS

Sixty-three cadaveric upper extremities from thirty-five cadavers were studied. A muscle splitting approach was utilized to locate the posterior interosseous nerve (PIN) at the point where it emerges from beneath the supinator. The supinator was carefully incised to expose the midpoint length of the nerve as it passes into the forearm while preserving the associated fascial connections, thereby preserving the relationship of the nerve with the muscle. We measured the transepicondylar distance (TED), PIN distance in the forearm’s neutral rotation position, pronation position, supination position, and the nerve width. Two individuals performed measurements using a digital caliper with inter-observer and intra-observer blinding. The results were analyzed with the Wilcoxon-Mann-Whitney test for paired samples.

RESULTS

In pronation, the PIN was within two confidence intervals of 1.0 TED in 95% of cases (range 0.7-1.3 TED); in neutral, within two confidence intervals of 0.84 TED in 95% of cases (range 0.5-1.1 TED); in supination, within two confidence intervals of 0.72 TED in 95% of cases (range 0.5-0.9 TED). The mean PIN distance from the lateral epicondyle was 100% of TED in a pronated forearm, 84% in neutral, and 72% in supination. Predictive accuracy was highest in supination; in all cases the majority of specimens (90.47%-95.23%) are within 2 cm of the forearm position-specific percentage of TED. When comparing right to left sides for TEDs with the signed Wilcoxon-Mann-Whitney test for paired samples as well as a significance test (with normal distribution), the P-value was 0.0357 (significance - 0.05) indicating a significant difference between the two sides.

CONCLUSION

This “patient normalized” parameter localizes the PIN crossing a line drawn between the lateral epicondyle and the radial styloid. Accurate PIN localization will aid in diagnosis, injections, and surgical approaches.

Keywords: Posterior interosseous nerve, Radial nerve, Transepicondylar distance, Radial tunnel syndrome, Supinator syndrome

Core tip: We present a “patient normalized” parameter that localizes posterior interosseous nerve (PIN) crossing point with a line interconnecting the lateral epicondyle and the radial styloid, with the “70-85-100” rule. The mean PIN distance from the lateral epicondyle was 100% of transepicondylar distance (TED) in a pronated forearm, 85% in neutral, and 70% in supination. Predictive accuracy was highest in supination; in all cases the majority of specimens (90.47%-95.23%) are within 2 cm of the forearm position-specific percentage of TED. Non-invasive accurate PIN localization will aid in diagnosis, injections, surgical approaches, and understanding neurological symptoms in the forearm.