Clinical significance of measuring lumbar spinal stenosis on MRI
XING Wen-hua1, HAO Li-xia2, HUO Hong-jun1, YANG Xue-jun1, XIAO Yu-long1, LI Feng1, XIN Da-qi1
1.Department of Spine Surgery, The Second Affiliated Hospital of Inner Mongolia Medical College, Hohhot 010030, China;2.Department of Rahabilitation, the Affiliated Hospital of Inner Mongolia Medical College, Hohhot 010059, China
Abstract：Objective: To analyze the cause and morphologic characteristics of lumbar spinal stenosis in the guidance of treatment planning. Materials and Methods: Altogether 120 patients including 62 males and 58 females, age ranged from 45~76 years old, with an average of 57.2 years old. The patients were divided into 4 groups, that is 29 cases in the 40~49 years old group, 42 cases in the 50~59 years old group, 33 cases in the 60~69 years old group, and 16 cases in the 70~79 years old group. All the patients had MRI examinations of the lumbar spine. The morphologic characteristics of spinal laminae, spinal canal, ligamentum flavum, and articular joints were observed. The lamina thickness, anterior-posterior diameter of the spinal canal on sagittal view and transverse diameter of spinal canal on coronal view were measured. The thickness of ligamentum flavum was measured on axial view at the level of L2/L3, L3/L4, L4/L5 articular joints. The changes of the measured parameters at different ages and different spinal segments were analyzed. Results: The type of spinal stenosis: central type 27 cases, lateral recess stenosis 35 cases, mixed type 58 cases, proliferation of articular joints: unilateral 33 cases, bilateral 87 cases; the shape of the spinal canal: “triangle” 76 cases, cloverleaf 44 cases. The average thickness of ligamentum flavum at L2/L3 was 2.4 mm, at L5/S1 was 3.1 mm, which was thinner than 3.7 mm at the level of L3/L4, at the level of L4/L5 was 4.5 mm. The thickness of ligamentum flavum increased with increasing age, the increase of thickness was most obvious at the level of L4/L5. The thickness of spinal lamina was 4.5 mm at L5, which was the minimum and 5.8 mm at L3 which was the maximum. The transverse diameter of the spinal canal on coronal view was 4.7 mm at the level of L4/L5 which was the minimum, and maximum of 10.3 mm at the level of L2/L3. The changes of these parameters was not obvious with increasing of age. As the thickness of ligamentum flavum increased, the transverse diameter of spinal canal on coronal view decreased. Conclusions: ①Increase thickness of ligamentum flavum caused the decrease of the transverse diameter of the spinal canal on coronal view, bilateral articular joint especially the superior articular joint hyperplasia with inner aggregation is the main factor causes spinal stenosis. ②During operation should increase the transverse diameter of the spinal canal on coronal view, excise the thickened ligamentum flavum and the hyperplastic part of the articular process, expand the lateral recess, and preserve the spinal process complex.
2014, Vol. 25 
