Patterns of lumbar disc degeneration are different in degenerative disc disease and disc prolapse magnetic resonance imaging analysis of 224 patients.
BACKGROUND
Existing research on lumbar disc degeneration has remained inconclusive regarding its etiology, pathogenesis, symptomatology, prevention, and management. Degenerative disc disease (DDD) and disc prolapse (DP) are common diseases affecting the lumbar discs. Although they manifest clinically differently, existing studies on disc degeneration have included patients with both these features, leading to wide variations in observations. The possible relationship or disaffect between DDD and DP is not fully evaluated.


OBJECTIVE
To analyze the patterns of lumbar disc degeneration in patients with chronic back pain and DDD and those with acute DP.


METHODS
Prospective, magnetic resonance imaging-based radiological study.


METHODS
Two groups of patients (aged 20-50 years) were prospectively studied. Group 1 included patients requiring a single level microdiscectomy for acute DP. Group 2 included patients with chronic low back pain and DDD. Discs were assessed by magnetic resonance imaging through Pfirmann grading, Schmorl nodes, Modic changes, and the total end-plate damage score for all the five lumbar discs.


RESULTS
Group 1 (DP) had 91 patients and group 2 (DDD) had 133 patients. DP and DDD patients differed significantly in the number, extent, and severity of degeneration. DDD patients had a significantly higher number of degenerated discs than DP patients (p<.000). The incidence of multilevel and pan-lumbar degeneration was also significantly higher in DDD group. The pattern of degeneration also differed in both the groups. DDD patients had predominant upper lumbar involvement, whereas DP patients had mainly lower lumbar degeneration. Modic changes were more common in DP patients, especially at the prolapsed level. Modic changes were present in 37% of prolapsed levels compared with 9.9% of normal discs (p<.00). The total end-plate damage score had a positive correlation with disc degeneration in both the groups. Further the mean total end-plate damage score at prolapsed level was also significantly higher.


CONCLUSIONS
The results suggest that patients with disc prolapse, and those with back pain with DDD are clinically and radiologically different groups of patients with varying patterns, severity, and extent of disc degeneration. This is the first study in literature to compare and identify significant differences in these two commonly encountered patient groups. In patients with single-level DP, the majority of the other discs are nondegenerate, the lower lumbar spine is predominantly involved and the end-plate damage is higher. Patients with back pain and DDD have larger number of degenerate discs, early multilevel degeneration, and predominant upper lumbar degeneration. The knowledge that these two groups of patients are different clinically and radiologically is critical for our improved understanding of the disease and for future studies on disc degeneration and disc prolapse.
Department of Orthopaedics and Spine Surgery, Ganga Hospital, 313, Mettupalayam Rd, Coimbatore 641 011, Tamil Nadu, India.
Rishi M
RM
Kanna
Department of Orthopaedics and Spine Surgery, Ganga Hospital, 313, Mettupalayam Rd, Coimbatore 641 011, Tamil Nadu, India.
Ajoy Prasad
AP
Shetty
Department of Orthopaedics and Spine Surgery, Ganga Hospital, 313, Mettupalayam Rd, Coimbatore 641 011, Tamil Nadu, India. Electronic address: sr@gangahospital.com.
S
S
Rajasekaran
D000208:Acute Disease; D000328:Adult; D059350:Chronic Pain / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D003937:Diagnosis, Differential; D017586:Diskectomy; D005260:Female; D006801:Humans; D015994:Incidence; D055959:Intervertebral Disc Degeneration / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D007405:Intervertebral Disc Displacement / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D017116:Low Back Pain / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D008159:Lumbar Vertebrae / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012585:Sciatica / Q000453:epidemiology / Q000473:pathology / Q000601:surgery; D012720:Severity of Illness Index; D055815:Young Adult
Disc degeneration; Disc prolapse; Magnetic resonance imaging; Patterns