RESUMO
BACKGROUND: Several papers have studied the degenerative changes of endplates, but there are no publications referring to the Mexican population. OBJECTIVE: The purpose of the study is to report the incidence of Modic degenerative changes in the patients seen at the Spine Service, Monterrey Regional ISSSTE Hospital. Specific objectives are: to describe the type of Modic change and the most frequent location, to describe the degeneration patterns and to report the incidence of the various diagnoses made during 2009. METHODS: Incidence study using the MRI records at the Radiology Department, Monterrey Regional ISSSTE Hospital, interpreted blindly and independently by two observers. RESULTS: A total of 240 lumbar spine MRIs were reviewed, for a total of 1,200 intervertebral spaces. They were divided by age groups. Group I included 16 patients, Group II 32, Group III 80, and Group IV 112. No patients in Group I had Modic changes. Four patients (12.5%) in Group II had type II Modic changes with < 25% of endplate involvement. Eight patients in Group III had Modic changes with > 25% involvement of L4-L5 (10%); 32% of Group IV patients had changes, with L5-S1 as the most affected level. Most Modic changes (85%) were located in L4-L5 and L5-S1, with the latter as the most frequently affected level. Type I represented 5%, Type II 30%, and Type III 65%. The percentage of patients with Modic changes increased with age, which confirms that degenerative changes are age related. Morphologic disc changes are expressed as the percentage of affected patients in each group. Besides the severity of degeneration, the number of affected levels also increases with age. Thirty percent of patients ages 30-39 years have one or two degenerated levels, while 50% of those over age 50 have 3 or more degenerated levels. The most frequently degenerated level was L5-S1, followed by L4-L5 and L3-L4. The most frequent degeneration pattern was lower segment degeneration (L4-L5, L5-S1). A small proportion of patients over age 50 (4%) did not have disc degeneration, suggesting that age is not the only factor that determines their occurrence. CONCLUSIONS: The prevalence of Modic changes was 22% (52 patients). Eight patients had Type II Modic changes at two levels. The most affected levels were L4-L5 and L5-S1, in 85% of cases. Patients over 50 years of age were the most affected age group; frequency increased with age. The most frequent disc degeneration pattern was degeneration of the lower lumbar levels. Risk factors need to be further studied and the correlation with the degree of pain needs to be determined to obtain more information.