1. Introduction

Lumbar spinal canal stenosis (LSS) is a significant and prevalent condition affecting the spinal column, characterized by the narrowing of the spinal canal, which may result in nerve compression and various neurological symptoms. According to the World Health Organization (WHO), approximately 90% of the global population experiences lower back pain at least once in their lifetime, with LSS being one of the primary contributing factors. [1]

The accurate and early diagnosis of LSS is crucial for effective patient management and treatment. Traditional radiological diagnostic methods such as X-ray and computed tomography (CT) scans have been used to assess spinal abnormalities. However, these techniques have limitations in evaluating soft tissue structures, which play a crucial role in LSS pathology. Magnetic resonance imaging (MRI) has emerged as the gold standard for diagnosing LSS due to its superior ability to visualize soft tissues, spinal cord structures, and pathological changes within the spinal canal. [2], [3]

Anatomically, the lumbar spine consists of five vertebrae with intervertebral cartilage that contributes to spinal flexibility and shock absorption. The normal sagittal diameter of the lumbar spinal canal ranges from 20-25 mm, while the frontal diameter measures between 26-30 mm. [4] The spinal cord, housed within the spinal canal, extends approximately 44-45 cm in males and 41-42 cm in females, terminating at the conus medullaris and giving rise to the cauda equina. [5]

Various factors contribute to the development of LSS, including degenerative changes, herniated discs, and malignant tumors. [6] Karahan and Kuvshinov (2002) classified lumbar stenosis into four main types: (a) central stenosis, (b) central stenosis with lateral stenosis, (c) unilateral lateral stenosis, and (d) mixed stenosis, with central stenosis accounting for up to 52% of cases. [7] A significant cause of stenosis is lumbar disc herniation, commonly occurring at the L4-L5 and L5-S1 levels. [8] Additionally, malignant tumors, either primary or metastatic, can lead to significant narrowing of the spinal canal. [9]

This study aims to assess the role of MRI in diagnosing lumbar spinal canal stenosis by comparing MRI findings of healthy individuals with those of patients suffering from degenerative and tumorous spinal conditions. By examining key spinal canal parameters and their variations in pathological conditions, the research seeks to provide a comprehensive understanding of MRI’s effectiveness in identifying and grading the severity of LSS.

2. Materials and Methods

A total of 55 participants were included in this study, comprising 40 patients with lumbar spinal canal stenosis and 15 healthy individuals as controls. All participants underwent MRI examination using the "Magnetom Open Viva" scanner, installed in the radiology department of the multidisciplinary clinic at the Andijan State Medical Institute. Among the patients, 25 were diagnosed with degenerative spinal changes, while 15 presented with malignant spinal tumors.

Key MRI parameters assessed included:

• Middle sagittal and frontal diameters of the lumbar spinal canal at the bony border.

• Middle sagittal and frontal diameters at the dural sac border.

• Vertical diameter measured in a straight projection.

Statistical Analysis

Statistical analysis was performed using SPSS software (version 25.0, IBM Corp.). Continuous variables were expressed as means ± standard deviations (SD). The Kolmogorov-Smirnov test was used to assess data normality. Differences between the patient and control groups were analyzed using the independent t-test for normally distributed data and the Mann-Whitney U test for non-normally distributed data. A p-value of <0.05 was considered statistically significant.

3. Results and Discussion

Using MRI, we analyzed the lumbar spine canal dimensions in 15 healthy individuals to establish baseline parameters (Table 1). The mid-sagittal diameter of the bony border of the fifth lumbar vertebra was found to be 13.2% larger than that of the first lumbar vertebra, while the corresponding soft tissue measurements showed an 11.9% increase. The frontal diameter at the fifth lumbar level was also significantly wider, with bone and soft tissue measurements exceeding those at the first lumbar vertebra by 17.8% and 19.5%, respectively. Additionally, the vertical diameter at the L5-S1 intervertebral level was 27.3% greater than that measured at L1-L2. These findings provide a reference framework for assessing stenosis severity by comparing pathological deviations from these normal values.

Table 1. The normal anatomical seizes of the parameters of the lumbar spine canal measured by the MRI method (in M+m, mm.)

Among 25 patients diagnosed with degenerative lumbar spine conditions, the distribution of intervertebral pathologies was as follows: L1-L2 (3.9%), L2-L3 (8.8%), L3-L4 (17.0%), L4-L5 (38.9%), and L5-S1 (31.4%). Notably, herniation and protrusions were most frequently observed at L4-L5 and L5-S1 (Table 2). When compared to healthy individuals, all key lumbar canal parameters showed a reduction in size among patients with degenerative-dystrophic conditions, further confirming the role of MRI in detecting and quantifying stenosis progression.

Table 2. The size of the parameters determined by the MRI method of stenosis caused by lumbar spinal channel degenerative-dystrophic diseases, (in M+M, mm), the size of the parameters of healthy people in the denominator

In patients with degenerative – dystrophic disease, intervertebral cartilage protrusion and hernia occurred in 4 different types (Table 3). They consist of diffuse, median, paramedian and dorsal-lateral hernias. They include diffuse type 16.0 %, median type 32.0%, paramedian type 32.0%, and vertebrate type 20.0%. Depending on the distribution in the spine, one-cell was found in 56.0%, two-layer in 32.0%, three-cell in 8.0%, four-layer in 4.0% of patients.

Table 3. MRI-guided variants of a single-layer and multi-layer hernia of the lumbar vertebrae

There is a high incidence of median and paramedian, unilateral and bilateral among hernias. In the diagnosis of such pathologies, the MRI method has the highest potential.

Malignant tumors inside or outside the canal in addition to vertebral protrusion and hernia play a major role in the origin of lumbar spinal canal stenosis. We examined the significancy of malignant tumors in stenosis calling using the MRI method in 15 patients. Depending on the location of malignant tumors, we found that they are mainly in intramedular, extramedular-intradural and extradural types (Figures 1 and 2). These malignant tumors are difficult to detect in diagnostic methods other than the MRI method.

Figure 1. Patient Kadyrov N. born in 1971. The malignant tumor is located mainly in the out of canal and partially penetrated into the canal. Stenosis in the subcompensatory phase occurred

Figure 2. Patient Novikov. born in 1982. Malignant tumor was located inside the canal, the canal was divided into two parts (blocks). Decompensated stenosis

These figures depict an MR-tomogram of malignant tumors in the L3 spine. In the first figure, a tumor with a surface of 1475 mm² was located mostly outside the canal, with part of it passing into the canal and partially crushing the spinal cord, resulting in stenosis in the subcompensatory phase of the spinal canal. In the second image, a malignant tumor with a surface of 614 mm² was located inside the canal, completely concealing (blocking) the canal and causing severe decompensator stenosis of the spinal canal in the patient.

4. Conclusions

The conclusion is that stenosis of the lumbar spine canal occurs as a result of severe degenerative trauma of the spine, in this disease the canal narrows and the spinal cord is pinched. With the help of the MRI method, it is possible to study at a high level the normal and pathological condition of the lumbar spine canal. All pathalogies that cause stenosis of the lumbar spine canal can be detected by the MRI method accurately and without harm to the patient.

ACKNOWLEDGEMENTS

This study was conducted without any external funding.

Conflicts Interest

The authors declare that there are no conflicts of interest regarding the publication of this paper.