Spinal Foraminal Stenosis - Novel methods and MRI in functional positions to improve diagnostics

Abstract

Background: Symptomatic spinal foraminal stenosis can cause radiculopathy, sensory disruptions, and motor weaknesses in the extremities. These symptoms typically present intermittently and are closely linked to various functional positions or postures. The common diagnostic method includes a relaxed supine MRI, which brings up an important consideration: Could this relaxed position potentially mask pathologies that are otherwise evident in the postures or situations that trigger symptoms? Aim: The primary objective was to investigate alterations in the properties of the spinal foramina and adjacent tissues with MRI during functional positions. Methods: A systematic review of validated classification systems for spinal foraminal stenosis was carried out (Study I). In the next study, the lumbar spine was studied in eighty-nine patients using quantitative and qualitative means with Magnetic Resonance Imaging (MRI) under axial loading (Study II). Then, a new compression device for the cervical spine was introduced on ten healthy volunteers employing a simulated Spurling test, acquiring MR images in the provoked position (Study III). Furthermore, ten patients with intermittent arm radiculopathy and confirmed one or two level cervical foraminal stenosis were examined in a position of provoked arm pain during a simulated Spurling test (Study IV). In the last study, zero-echo-time (ZTE) sequences were acquired in both relaxed and provoked positions and were then integrated into Sectra® CT-based Micromotion Analysis (CTMA) for analysis (Study V). Results: Three validated classification systems for spinal foraminal stenosis were identified. During axial loading of the lumbar spine a reduced foraminal area and altered foraminal gradings were found. The cervical compression device was successfully introduced on healthy volunteers, demonstrating the consistent application of a simulated Spurling test, further accomplishing a significant increase in the cervical angle and a decrease in the foraminal cross-distance in the axial image plane. In Study IV, all patients with cervical foraminal stenosis withstood the simulated Spurling test. In nine out of ten subjects, the test provoked concordant arm radiculopathy, resulting in significant increases in the foraminal gradings. Finally, the ZTE images were successfully employed in the CTMA, showing the most movement in C4/C5 levels compared with C5/C6 and C6/C7 during an ongoing Spurling test. Conclusion: The identified validated classification systems proved to be usable in the three consecutive studies. MRI in functional positions offers a promising avenue for enhancing the diagnostic accuracy in diagnosing foraminal stenosis, particularly in patients with position-dependent symptoms. While there are challenges and limitations, the significant potential benefits in clinical practice warrant the continued exploration and refinement of these techniques.