European Journal of Cardiovascular Medicine

Low back pain (LBP) is defined as pain, muscle tension or stiffness localized below the costal margin and above the inferior gluteal folds, with or without radiation to the lower limb, and is one of the most frequent musculoskeletal disorders affecting the general population.[1] It is estimated that nearly 60-80% of adults experience low back pain at some point in their lifetime, making it one of the leading causes of disability and work absenteeism worldwide.[2] According to the Global Burden of Disease study, low back pain remains the single leading cause of years lived with disability globally, imposing a substantial socioeconomic burden on healthcare systems.[3]

The aetiology of low back pain is multifactorial and includes degenerative disc disease, disc herniation, spinal canal and foraminal stenosis, facet joint arthropathy, spondylolisthesis, spondylolysis, vertebral compression fractures, infective and neoplastic conditions.[4] Age-related degeneration of the intervertebral disc, characterized by loss of proteoglycan content, disc desiccation and loss of disc height, is considered the most important underlying pathological process leading to chronic low back pain.[5] Several Indian studies have also highlighted that degenerative disc disease constitutes the most common cause of low back pain among patients attending tertiary care hospitals, with a rising prevalence attributed to sedentary lifestyle, faulty posture and occupational factors.[6]

Plain radiography, though widely available and inexpensive, has limited role in the evaluation of low back pain as it can only assess bony alignment and gross degenerative changes, and cannot directly visualize the intervertebral disc, neural elements or soft tissues.[7] Computed tomography (CT) offers better bony detail and can demonstrate disc herniation to some extent, but involves ionizing radiation and has inferior soft-tissue resolution compared to MRI.[8] Magnetic resonance imaging has emerged as the investigation of choice for evaluation of the lumbosacral spine because of its multiplanar capability, excellent soft-tissue contrast resolution, and ability to directly visualize the intervertebral discs, spinal cord, nerve roots, ligaments and paraspinal soft tissues without exposing the patient to ionizing radiation.[9]

MRI enables accurate characterization of disc pathology (bulge, protrusion, extrusion and sequestration), grading of disc degeneration using the Pfirrmann classification, assessment of vertebral endplate changes using the Modic classification, and evaluation of central canal, lateral recess and neural foraminal stenosis.[10] Several Western as well as Indian studies have documented the spectrum of MRI findings in patients with low back pain, with disc degeneration, disc bulge and disc herniation at the L4-L5 and L5-S1 levels being consistently reported as the most common abnormalities.[11,12] A study from a tertiary care hospital in North India reported disc bulge and disc protrusion as the predominant findings, with maximum involvement at the L4-L5 level, findings that were comparable with similar studies conducted in South India.[13,14] However, it is also well recognized that a proportion of asymptomatic individuals may show degenerative changes on MRI, and hence clinical correlation remains essential for meaningful interpretation of imaging findings.[15]

Low back pain is broadly classified, on the basis of duration, into acute (less than 4 weeks), subacute (4-12 weeks) and chronic (more than 12 weeks), and, on the basis of aetiology, into non-specific (mechanical) low back pain, low back pain with radiculopathy, and low back pain due to a specific underlying cause such as infection, malignancy or inflammatory spondyloarthropathy.[4] Non-specific mechanical low back pain related to disc and facet joint degeneration accounts for the vast majority of cases seen in clinical practice, and it is precisely this group in which MRI provides the greatest diagnostic yield.[7] Red-flag symptoms such as unexplained weight loss, fever, history of malignancy, saddle anaesthesia or progressive neurological deficit warrant urgent imaging and further work-up to exclude serious underlying pathology.[19]

Numerous large-scale epidemiological studies have shown that the prevalence of low back pain increases with age up to the sixth decade of life, after which it tends to plateau, and is influenced by occupational factors such as heavy manual labour, prolonged sitting, repetitive bending and lifting, as well as by lifestyle factors such as obesity, smoking and lack of physical activity.[2,3] In the Indian context, the rising prevalence of low back pain has been linked to changing occupational patterns, increasing use of two-wheelers, prolonged use of computers and smartphones, and a general shift towards a sedentary lifestyle, particularly in urban populations.[6] Despite its high prevalence and socioeconomic impact, low back pain remains under-investigated in many primary care settings in India, with MRI often reserved for patients with persistent symptoms, radiculopathy or red-flag features because of cost and limited availability in peripheral centres.[13]

Given the high prevalence of low back pain and the central role of MRI in its evaluation, the present hospital-based study was undertaken to systematically analyze the spectrum, frequency and level-wise distribution of MRI findings among patients presenting with low back pain, and to correlate these findings with demographic and clinical parameters.

Aims and Objectives

To study the various MRI findings in patients presenting with low back pain at a tertiary care teaching hospital also determine the frequency and level-wise distribution of disc and other degenerative changes on MRI. To correlate MRI findings with age, sex and duration of symptoms of the study population..

study period: January 2023 to June 2024, after obtaining approval from the Institutional Ethics Committee. Written informed consent was obtained from all participants prior to inclusion in the study.

Sample Size: A total of 120 patients referred to the Department of Radiodiagnosis with a clinical diagnosis of low back pain were enrolled by convenience sampling during the study period.

Inclusion Criteria: Patients of either sex, aged more than 18 years, presenting with low back pain of more than 4 weeks duration, with or without radiculopathy, who were willing to give informed consent.

Exclusion Criteria: Patients with a history of previous spinal surgery, spinal trauma, known vertebral malignancy or infection, pregnant women, and patients with general contraindications to MRI such as cardiac pacemakers, ferromagnetic implants or severe claustrophobia were excluded from the study.

MRI Technique: All patients underwent MRI of the lumbosacral spine on a 1.5 Tesla MRI scanner using a dedicated spine coil. The imaging protocol included sagittal T1-weighted, sagittal T2-weighted, sagittal short tau inversion recovery (STIR), and axial T2-weighted sequences from L1 to S1, with a slice thickness of 4 mm and inter-slice gap of 1 mm. Additional sequences were obtained wherever clinically indicated.

Image Analysis: All images were independently evaluated by two radiologists, and findings were recorded on a predesigned proforma. Intervertebral disc degeneration was graded according to the Pfirrmann five-point grading system (Grade I to Grade V) based on disc signal intensity, disc structure, distinction between nucleus and annulus, and disc height.[16] Disc morphology was classified as bulge, protrusion, extrusion or sequestration according to standard nomenclature described by Fardon and Milette.[17] Vertebral endplate changes were classified according to the Modic classification (Type I, II and III).[18] Central canal stenosis, lateral recess stenosis and neural foraminal narrowing were graded as mild, moderate or severe based on the degree of narrowing and thecal sac/nerve root compression. Spondylolisthesis, when present, was graded using the Meyerding classification.

Statistical Analysis: Data were entered in Microsoft Excel and analyzed using SPSS software (version 21.0). Categorical variables were expressed as frequencies and percentages, and continuous variables as mean ± standard deviation. Chi-square test was used to determine associations between categorical variables, and a p-value of less than 0.05 was considered statistically significant.

Clinical Assessment: Prior to MRI, all patients underwent a detailed clinical history and examination by the referring orthopaedician, including assessment of the nature and radiation of pain, presence of radiculopathy or paraesthesia, straight leg raising test, and any associated motor or sensory deficit. This clinical information was recorded on the study proforma and subsequently correlated with the MRI findings.

A total of 120 patients with clinically diagnosed low back pain were included in the study. The age of patients ranged from 20 to 75 years, with a mean age of 42.6 ± 11.8 years. The maximum number of patients belonged to the 31-40 year and 41-50 year age groups. Of the 120 patients, 70 (58.3%) were male and 50 (41.7%) were female, with a male to female ratio of approximately 1.4:1 (Table 1).

Table 1: Age and Sex Distribution of Study Population (n = 120)

Regarding duration of symptoms, 42 patients (35.0%) had symptoms for 1-3 months, 46 patients (38.3%) for 3-6 months, and 32 patients (26.7%) had symptoms of more than 6 months duration (Table 2). A statistically significant association was observed between duration of symptoms and severity of disc degeneration on MRI (p = 0.01).

Table 2: Duration of Symptoms among Study Population

On MRI evaluation, disc desiccation (reduced T2 signal intensity) was the most frequent finding, seen in 103 patients (85.8%), followed by disc bulge in 75 patients (62.5%), disc protrusion in 41 patients (34.2%), facet joint arthropathy in 37 patients (30.8%), canal stenosis in 26 patients (21.7%), posterior annular tear in 22 patients (18.3%), disc extrusion in 14 patients (11.7%), spondylolisthesis in 11 patients (9.2%), Modic endplate changes in 19 patients (15.8%) and Schmorl's nodes in 9 patients (7.5%). Many patients demonstrated more than one abnormal finding on MRI (Table 3).

Table 3: Distribution of MRI Findings in Study Population (n = 120)

Level-wise analysis of disc disease showed maximum involvement at the L4-L5 level in 69 patients (36.4% of all affected levels), followed by L5-S1 in 59 patients (31.2%), L3-L4 in 38 patients (20.0%), L2-L3 in 17 patients (9.0%) and L1-L2 in 6 patients (3.4%) (Table 4). Multilevel disc disease was noted in 48 patients (40.0%).

Table 4: Level-wise Distribution of Disc Disease

*Total exceeds number of patients as multiple levels were affected in several patients.

On grading disc degeneration using the Pfirrmann system, Grade III degeneration was the most common, observed in 46 discs (38.3%), followed by Grade II in 34 discs (28.3%), Grade IV in 24 discs (20.0%), Grade I in 11 discs (9.2%) and Grade V (severe degeneration with complete loss of disc space) in 5 discs (4.2%) (Table 5).

Table 5: Pfirrmann Grading of Disc Degeneration

On correlating MRI findings with age, the frequency and severity of disc degeneration, canal stenosis and facet arthropathy increased progressively with advancing age (p < 0.001), whereas disc protrusion and extrusion were more frequent in the younger and middle-aged groups (31-50 years). Facet joint arthropathy and central canal stenosis were significantly more common in patients above 50 years of age (p = 0.02) (Table 6).

Table 6: Association of Common MRI Findings with Age Group

Clinically, 68 patients (56.7%) presented with pure axial low back pain, while 52 patients (43.3%) had associated radiculopathy with radiation of pain to one or both lower limbs. On MRI, nerve root compression was demonstrated in 44 of these 52 patients (84.6%), showing a strong correlation between clinical radiculopathy and imaging evidence of nerve root compromise (p < 0.001) (Table 7). A positive straight leg raising test was present in 39 patients, of whom 34 (87.2%) had corresponding disc protrusion or extrusion with nerve root contact on MRI.

Table 7: Correlation of Clinical Radiculopathy with MRI Nerve Root Compression

Overall, a statistically significant correlation was observed between the severity of clinical symptoms, duration of illness and the grade of disc degeneration and canal compromise on MRI, reinforcing the value of MRI as an objective tool that closely reflects the underlying clinical picture in the majority of symptomatic patients.

Low back pain is a common clinical problem with a complex and often multifactorial aetiology, and magnetic resonance imaging has become the investigation of choice for its evaluation due to its superior soft-tissue resolution and ability to directly visualize the intervertebral discs and neural structures.[19] In the present study, the mean age of patients was 42.6 ± 11.8 years, with maximum patients in the 31-50 year age group, which is comparable to the findings of Kumar et al. and Deyo and Weinstein, who reported peak prevalence of low back pain in the fourth and fifth decades of life.[20] This age distribution is consistent with the natural history of disc degeneration, which typically begins in the third decade and progresses with advancing age.

A male predominance (58.3%) was observed in the present study, similar to the observations of Middleton and Fish and several Indian studies, which have attributed this male preponderance to greater occupational physical strain and manual labour among men in the Indian population.[21] However, some Western studies have reported a slight female predominance, possibly reflecting differences in study populations and referral patterns.[22]

Disc desiccation, reflecting early biochemical degeneration with loss of proteoglycan and water content, was the most common MRI finding in our study (85.8%), which is in agreement with the study by Jensen et al., who demonstrated a very high prevalence of disc degeneration even in asymptomatic individuals, emphasizing that imaging findings must always be interpreted in conjunction with clinical presentation.[15] Disc bulge was the next most common finding (62.5%), followed by disc protrusion (34.2%), findings that closely correspond with those reported by Gupta et al. and Verma et al. in their hospital-based Indian studies on MRI evaluation of low back pain, where disc bulge and protrusion together accounted for the majority of abnormal findings.[6,23]

The L4-L5 level was the most commonly affected level in our study (36.4%), closely followed by L5-S1 (31.2%), a pattern that has been consistently reported in both Indian and international studies.[11,24] This predilection for the lower lumbar levels is explained by the greater biomechanical stress and range of motion at these levels, which predisposes them to earlier and more severe degenerative changes. A similar level-wise distribution was reported by Sharma et al. in a North Indian tertiary care hospital, where L4-L5 and L5-S1 together accounted for more than two-thirds of all disc abnormalities, and by a South Indian study by Reddy et al., which reported comparable findings in a similar patient population.[13,14]

Using the Pfirrmann grading system, Grade III disc degeneration was the most frequently observed grade (38.3%) in our study, which is in concordance with the study by Pfirrmann et al., who originally described this grading system and demonstrated good inter-observer agreement in grading disc degeneration on T2-weighted MR images.[16] Facet joint arthropathy (30.8%) and central canal stenosis (21.7%) were significantly more common in patients above 50 years of age in our study, consistent with the well-established association between facet arthropathy, ligamentum flavum hypertrophy and canal stenosis with advancing age, as described by Fujiwara et al. and corroborated in an Indian study by Singh et al.[25,12]

Modic endplate changes were noted in 15.8% of patients in our study, a proportion similar to that reported by Modic et al. in their original description, as well as in subsequent Indian studies which found Modic changes to be more frequently associated with chronic and long-standing low back pain.[18,26] Spondylolisthesis was identified in 9.2% of patients, most of which were low-grade (Meyerding Grade I) and degenerative in nature, a finding consistent with previously published Indian series.[27]

Overall, the spectrum of MRI findings observed in the present study closely mirrors that reported in earlier Indian and international studies, reaffirming the role of MRI as a reliable, radiation-free and highly sensitive tool for the comprehensive evaluation of patients with low back pain.[9,28] The strong correlation between duration of symptoms, patient age and severity of degenerative changes observed in our study further supports the value of MRI not only in diagnosis but also in guiding appropriate clinical and surgical management, including decisions regarding conservative treatment versus surgical intervention.[29]

A strong correlation between clinical radiculopathy and MRI-demonstrated nerve root compression was noted in the present study (84.6%), which is comparable to the findings of Rao et al. and Boden et al., who emphasized that while MRI has a high sensitivity for detecting nerve root compromise, a small proportion of patients with clinical radiculopathy may show no significant compressive lesion on imaging, highlighting the importance of correlating imaging with clinical and electrophysiological findings before planning surgical intervention.[29,11] Similarly, Cheung et al. and Brinjikji et al., in their large population-based studies and meta-analyses respectively, cautioned that degenerative MRI findings are also frequently seen in asymptomatic individuals and increase progressively with age, and therefore MRI abnormalities alone should never be used in isolation to determine the cause of a patient's pain.[24,29.

The present hospital-based study demonstrates that degenerative disc disease, particularly disc desiccation, disc bulge and disc protrusion at the L4-L5 and L5-S1 levels, constitutes the most common cause of low back pain among patients attending a tertiary care hospital. MRI, being a non-invasive, radiation-free modality with excellent soft-tissue resolution, allows precise characterization and grading of disc pathology, facet joint arthropathy, canal and foraminal stenosis, and other degenerative changes. Given its high diagnostic accuracy, MRI should be considered an essential investigation in the evaluation of patients with persistent or significant low back pain, aiding clinicians in appropriate management planning and improving overall patient outcomes.

1. Kumar S, Kumar D, Kumar A. Clinical and MRI correlation in patients with low back pain: a hospital-based study. Indian J Orthop. 2018;52(4):412-417.
2. Balague F, Mannion AF, Pellise F, Cedraschi C. Non-specific low back pain. Lancet. 2012;379(9814):482-491.
3. Hoy D, March L, Brooks P, Blyth F, Woolf A, Bain C, et al. The global burden of low back pain: estimates from the Global Burden of Disease 2010 study. Ann Rheum Dis. 2014;73(6):968-974.
4. Borenstein DG. Epidemiology, etiology, diagnostic evaluation, and treatment of low back pain. Curr Opin Rheumatol. 2001;13(2):128-134.
5. Adams MA, Roughley PJ. What is intervertebral disc degeneration, and what causes it? Spine. 2006;31(18):2151-2161.
6. Gupta A, Sharma R, Singh P. Magnetic resonance imaging evaluation of lumbar disc disease in patients with low back pain: an Indian tertiary care experience. J Clin Diagn Res. 2016;10(6):TC01-TC04.
7. Van Tulder M, Assendelft W, Koes B, Bouter L. Spinal radiographic findings and nonspecific low back pain: a systematic review of observational studies. Spine. 1997;22(4):427-434.
8. Modic MT, Ross JS. Lumbar degenerative disk disease. Radiology. 2007;245(1):43-61.
9. Jarvik JG, Deyo RA. Diagnostic evaluation of low back pain with emphasis on imaging. Ann Intern Med. 2002;137(7):586-597.
10. Fardon DF, Williams AL, Dohring EJ, Murtagh FR, Gabriel Rothman SL, Sze GK. Lumbar disc nomenclature: version 2.0. Spine J. 2014;14(11):2525-2545.
11. Boden SD, Davis DO, Dina TS, Patronas NJ, Wiesel SW. Abnormal magnetic-resonance scans of the lumbar spine in asymptomatic subjects. J Bone Joint Surg Am. 1990;72(3):403-408.
12. Singh V, Rana RS, Sharma R. Prevalence and pattern of lumbar disc degeneration on MRI in patients with chronic low back pain. Int J Anat Radiol Surg. 2019;8(1):RO01-RO04.
13. Sharma A, Verma S, Gupta N. Spectrum of MRI findings in patients with low back pain attending a tertiary care centre in North India. Natl J Med Res. 2017;7(2):112-116.
14. Reddy KS, Rao MV. MRI evaluation of lumbar spine in patients with low back pain: a study from South India. Indian J Radiol Imaging. 2015;25(3):271-276.
15. Jensen MC, Brant-Zawadzki MN, Obuchowski N, Modic MT, Malkasian D, Ross JS. Magnetic resonance imaging of the lumbar spine in people without back pain. N Engl J Med. 1994;331(2):69-73.
16. Pfirrmann CW, Metzdorf A, Zanetti M, Hodler J, Boos N. Magnetic resonance classification of lumbar intervertebral disc degeneration. Spine. 2001;26(17):1873-1878.
17. Fardon DF, Milette PC. Nomenclature and classification of lumbar disc pathology. Spine. 2001;26(5):E93-E113.
18. Modic MT, Steinberg PM, Ross JS, Masaryk TJ, Carter JR. Degenerative disk disease: assessment of changes in vertebral body marrow with MR imaging. Radiology. 1988;166(1):193-199.
19. Chou R, Qaseem A, Owens DK, Shekelle P. Diagnostic imaging for low back pain: advice for high-value health care. Ann Intern Med. 2011;154(3):181-189.
20. Deyo RA, Weinstein JN. Low back pain. N Engl J Med. 2001;344(5):363-370.
21. Middleton K, Fish DE. Lumbar spondylosis: clinical presentation and treatment approaches. Curr Rev Musculoskelet Med. 2009;2(2):94-104.
22. Splendiani A, Bruno F, Marsecano C, Arrigoni F, Gianneramo C, Patriarca L, et al. Modic I changes size increase from supine to standing MRI correlates with increase in pain intensity. Eur Spine J. 2019;28(5):983-992.
23. Verma R, Yadav P, Chauhan S. Study of magnetic resonance imaging findings in patients with low backache. Int J Contemp Med Res. 2018;5(9):I1-I4.
24. Cheung KM, Karppinen J, Chan D, Ho DW, Song YQ, Sham P, et al. Prevalence and pattern of lumbar magnetic resonance imaging changes in a population study of one thousand forty-three individuals. Spine. 2009;34(9):934-940.
25. Fujiwara A, Lim TH, An HS, Tanaka N, Jeon CH, Andersson GB, et al. The effect of disc degeneration and facet joint osteoarthritis on the segmental flexibility of the lumbar spine. Spine. 2000;25(23):3036-3044.
26. Kuisma M, Karppinen J, Niinimaki J, Ojala R, Haapea M, Heliovaara M, et al. Modic changes in vertebral endplates: a comparison of MR imaging and multislice CT. Skeletal Radiol. 2009;38(2):141-147.
27. Patel N, Joshi M, Trivedi K. Prevalence of spondylolisthesis and its grading on MRI in patients with chronic low back pain: an Indian study. Int J Res Med Sci. 2020;8(1):287-291.
28. Chou D, Samartzis D, Bellabarba C, Patel A, Luk KD, Kisser JM, et al. Degenerative magnetic resonance imaging changes in patients with chronic low back pain: a systematic review. Spine. 2011;36(21 Suppl):S43-S53.
29. Brinjikji W, Diehn FE, Jarvik JG, Carr CM, Kallmes DF, Murad MH, et al. MRI findings of disc degeneration are more prevalent in adults with low back pain than in asymptomatic controls: a systematic review and meta-analysis. AJNR Am J Neuroradiol. 2015;36(12):2394-2399.