Julio Urrutia

Introduction: The prevalence of ossification of the posterior longitudinal ligament (OPLL) has been primarily studied in East Asian countries; its prevalence in Western populations remains to be elucidated. We aimed to determine the prevalence of OPLL in a Chilean population aged 60 years and older using fluorine-18 fluorodeoxyglucose positron emission tomography and CT (PET-CT) as screening tool. Methods: We evaluated patients between 60 and 73 years consecutively studied with PET-CT in a University Hospital. We assessed whole-body CT scans in both sagittal and axial views to detect the presence of OPLL. We used the Mann-Whitney test to analyze continuous variables, the Fisher test for categorical variables, and a logistic regression analysis to determine the independent effect of age and sex on the presence of OPLL. Results: We studied 1,009 patients (median age = 66 years); 597 were males (59.17%). Nineteen patients had OPLL, with a prevalence of 1.88% (1.04 to 2.72). OPLL was more prevalent in men (2.68%) than in women (0.73%; P = 0.02). All cases presented cervical involvement; only one had cervical and thoracic OPLL. The median age of patients with OPLL (64 years) and without OPLL (66 years) was not statistically different ( P = 0.09). Male sex independently influenced the presence of OPLL (odds ratio = 3.85 [1.11 to 13.33]), age did not (odds ratio = 0.89 [0.78 to 1.02]). Discussion: This is the first study evaluating the prevalence of OPLL in Latin America. It shows a prevalence alike that in non-Asian populations in the United States and lower than the prevalence described in Asian populations.

Purpose There is a growing interest in using computed tomography (CT) scans to opportunistically assess bone mineral density via Hounsfield units (HU). Previous studies have shown lower HU in patients with vertebral compression fractures (VCFs) and that HU can predict pre-existing VCFs. This study evaluated whether HU from CT scans can predict the number of prevalent VCFs. Methods We studied 353 patients (199 females) aged 58 and older who underwent thorax-abdomen-pelvis or thoracic-lumbar CT scans. HU were measured at T11 and L1. Inter- and intra-observer agreement measuring HU was assessed. We compared mean HU values using the T-test, performed Spearman’s correlation between HU and VCFs, and conducted logistic and linear regression analyses to determine the independent effect of sex, age, and HU on the presence and number of VCFs. Results The median age was 73 years. Ninety-eight patients had at least one VCF, with 46 having one and 52 having two or more VCFs. Inter- and intra-observer agreement assessing HU was excellent (ICC = 0.98 and 0.99 respectively). Mean HU were significantly lower in patients with VCFs (91.14 ± 39.33) than in patients without VCFs (145.03 ± 41.07, p < 0.01). HU negatively correlated with the number of VCFs (r = − 0.54, p < 0.01). Logistic regression showed that age (p < 0.01) and HU (p < 0.01) predicted the presence of VCFs. Linear regression found that HU independently predicted the number of VCFs (p < 0.01), while age (p = 0.67) and sex (p = 0.12) did not. Conclusion HU from CT scans can predict the presence and number of VCFs.

Purpose Pola et al. described a clinical-radiological classification of pyogenic spinal infections (PSI) based on magnetic resonance imaging (MRI) features including vertebral destruction, soft tissue involvement, and epidural abscess, along with the neurological status. We performed an inter- and intra-observer agreement evaluation of this classification. Methods Complete MRI studies of 80 patients with PSI were selected and classified using the scheme described by Pola et al. by seven evaluators. After a four-week interval, all cases were presented to the same assessors in a random sequence for repeat assessment. We used the weighted kappa statistics (wκ) to establish the inter- and intra-observer agreement. Results The inter-observer agreement was substantial considering the main categories (wκ = 0.77; 0.71–0.82), but moderate considering the subtypes (wκ = 0.51; 0.45–0.58). The intra-observer agreement was substantial considering the main types (wκ = 0.65; 0.59–0.71), and moderate considering the subtypes (wκ = 0.58; 0.54–0.63). Conclusion The agreement at the main type level indicates that this classification allows adequate communication and may be used in clinical practice; at the subtypes level, the agreement is only moderate.