Lumbosacral plexus root thickening: Establishing normal root dimensions using magnetic resonance neurography

Abstract

Disorders affecting the lumbosacral plexus (LSP) can alter root diameter. Our aim was to determine normal LSP nerve root dimensions using magnetic resonance neurography (MRN). Eleven asymptomatic patients (ages: 18-53, mean: 34 years) underwent MRN of the LSP on a 3 T scanner with an 8-channel torso-PA coil. IDEAL T2-weighted images were acquired and nerve root dimensions were measured from the second lumbar (L2) to the first sacral (S1) vertebrae on the coronal plane, 5 mm from the dorsal root ganglion (DRG). Root size was recorded by three separate groups of radiologists with different levels of expertise. Additional LSP-MRN images were acquired from a fresh-frozen cadaver specimen using the same scanner and parameters identical to those described above. Subsequently, two experienced anatomists dissected and measured the LSP roots at exactly the same distance from the DRG, using an electronic caliper. Mean root size values recorded (± standard deviation) in the asymptomatic patients were as follows: L2: 3.12 mm (±0.92), L3: 4.29 mm (±0.95), L4: 5.13 mm (±0.79), L5: 5.29 mm (±0.9), and S1: 5.38 mm (±0.7). The correlation coefficients were 0.72 between the patient and cadaver MRN results and 0.79 between the patient and dissected cadaver MRN results. Inter-observer agreements were 0.73 among the radiologist groups and 0.87 between the anatomists conducting dissections. We believe MRN provides reliable assessments of LSP root thickness. More extensive studies should be conducted to confirm the results described here. Clin. Anat. 31:782-787, 2018. © 2018 Wiley Periodicals, Inc.

Human lumbosacral root and ligamentum flavum thicknesses: a magnetic resonance study

“…The outcome of this study revealed that the LSP thickness increases by moving downward towed the sacrum as previously reported (14,16,17). The only study that contradicts the concept of gradual increase in LSP thickness was conducted by IZCI et al who reported that L1 is the thinnest root of the LSP (4.1 mm) and L4 is the thickest (5.5 mm) root of the LSP.…”

“…The exact dimensions of human LSP thickness are varied in the literature. The clinical importance of morphometric data on LSP thickness has been emphasized by many studies (2,5,(14)(15)(16)(17). In this retrospective study, the thickness of LSP showed a gradual increase known as cephalo-caudal pattern from L1 to S1 (Table 1).…”

Application of a nerve stereoscopic reconstruction technique based on ultrasonic images in the diagnosis of neuralgic amyotrophy

“…Despite the fact that MRI can be utilized for three-dimensional (3D) reconstruction of nerve tissues and ultrasound can be used for panoramic imaging of nerve tissues at present, they have the following limitations: 1. The boundary between the 3D neural imaging and surrounding tissue is blurred ( Kim et al, 2007 ; Chaves et al, 2018 ; van Rosmalen et al, 2021 ). 2.…”

Leonardo da Vinci and his contribution to our understanding of the lumbosacral plexus

“…Unfortunately, most of da Vinci's work was unpublished, and thus, his brilliant records were not appreciated in the scientific literature of his day [2]. However, today, his accomplishments in neuroanatomy continue to be recognized [4,5]. …”