MRI classification of interspinous ligament degeneration of the lumbar spine: intraobserver and interobserver reliability and the frequency of disagreement

Establishment of a risk prediction model for residual low back pain in thoracolumbar osteoporotic vertebral compression fractures after percutaneous kyphoplasty

OBJECTIVE

This study aims to identify potential independent risk factors for residual low back pain (LBP) in patients with thoracolumbar osteoporotic vertebral compression fractures (OVCFs) following percutaneous kyphoplasty (PKP) treatment. Additionally, we aim to develop a nomogram that can accurately predict the occurrence of residual LBP.

METHODS

We conducted a retrospective review of the medical records of thoracolumbar OVCFs patients who underwent PKP treatment at our hospital between July 2021 and December 2022. Residual LBP was defined as the presence of moderate or greater pain (VAS score ≥ 4) in the low back one day after surgery, and patients were divided into two groups: the LBP group and the non-LBP group. These patients were then randomly allocated to either a training or a validation set in the ratio of 7:3. To identify potential risk factors for residual LBP, we employed lasso regression for multivariate analysis, and from this, we constructed a nomogram. Subsequently, the predictive accuracy and practical clinical application of the nomogram were evaluated through a receiver operating characteristic (ROC) curve, a calibration curve, and a decision curve analysis (DCA).

RESULTS

Our predictive model revealed that five variables-posterior fascial oedema, intravertebral vacuum cleft, time from fracture to surgery, sarcopenia, and interspinous ligament degeneration-were correlated with the presence of residual LBP. In the training set, the area under the ROC was 0.844 (95% CI 0.772-0.917), and in the validation set, it was 0.842 (95% CI 0.744-0.940), indicating that the model demonstrated strong discriminative performance. Furthermore, the predictions closely matched actual observations in both the training and validation sets. The decision curve analysis (DCA) curve suggested that the model provides a substantial net clinical benefit.

CONCLUSIONS

We have created a novel numerical model capable of accurately predicting the potential risk factors associated with the occurrence of residual LBP following PKP in thoracolumbar OVCFs patients. This model serves as a valuable tool for guiding specific clinical decisions for patients with OVCFs.

Anatomy of the lumbar interspinous ligament: findings relevant to epidural insertion using loss of resistance

BACKGROUND AND OBJECTIVES

The 'loss of resistance' technique is used to determine entry into the epidural space, often by a midline needle in the interspinous ligament before the ligamentum flavum. Anatomical explanations for loss of resistance without entry into the epidural space are lacking. This investigation aimed to improve morphometric characterization of the lumbar interspinous ligament by observation and measurement at dissection and from MRI.

METHODS

Measurements were made on 14 embalmed donor lumbar spines (T12 to S1) imaged with MRI and then dissected along a tilted axial plane aligned with the lumbar interspace.

RESULTS

In 73 interspaces, median (IQR) lumbar interspinous plus supraspinous ligament length was 29.7 mm (25.5-33.4). Posterior width was 9.2 mm (7.7, 11.9), with narrowing in the middle (4.5 mm (3.0, 6.8)) and an anterior width of 7.3 mm (5.7, 9.8).Fat-filled gaps were present within 55 (75%). Of 51 anterior gaps, 49 (67%) were related to the ligamenta flava junction. Median (IQR) gap length and width were 3.5 mm (2.5, 5.1) and 1.1 mm (0.9, 1.7).Detection of gaps with MRI had 100% sensitivity (95% CI 93.5 to 100), 94.4% specificity (72.7, 99.9), 98.2% (90.4, 100) positive predictive value and 100% (80.5, 100) negative predictive value against dissection as the gold standard.

CONCLUSIONS

The lumbar interspinous ligament plus supraspinous ligament are biconcave axially. It commonly has fat-filled gaps, particularly anteriorly. These anatomical features may form the anatomical basis for false or equivocal loss of resistance.

Anatomical and Biomechanical Study of the Lumbar Interspinous Ligament

Objective

The lumbar interspinous ligaments (ISLs) are thin and short fibers connecting adjacent spinous processes. However, their morphology is variably described and their biomechanics are not well understood. Therefore, the purpose of this study was to assess the anatomy and biomechanics of the lumbar ISL.

Materials and Methods

Five fresh frozen cadaveric specimens were dissected posteriorly to reveal and study the lumbar ISL. Measurements of the ligaments included the anterior vertical height (length A), the posterior vertical height (length P), and the length (length H) at each lumbar level. Next, 17 lumbar vertebral levels from 6 cadaveric specimens were used for tensile strength testing. The ISLs were subjected to vertically controlled increasing manual tension. The force necessary to disrupt the ISL was recorded.

Results

All the ISLs ran horizontally in an anterior-posterior direction with a slight curve. The average of length A, length P, and length H on the right sides was 9.82, 9.57, and 20.12 mm, respectively. The average of length A, length P, and length H on the left sides was 11.56, 12.01, and 21.42 mm, respectively. The mean tensile strength of the ISL was 162.33 (N) at L1/2, 85.67 (N) at L2/3, and 79 (N) at L3/4. There was a significant difference in the tensile force between L1/2 and L2/3 and L1/2 and L3/4 (P < 0.05). The ligaments became weaker with a descent along the lumbar levels.

Conclusion

The results of this study might help surgeons understand pathology/trauma of the lumbar vertebral region.

Lumbar Ligament Sprain-degeneration and Prolapsed Lumbar Intervertebral Disc: A Frequent Missed Combination

Low back pain (LBP) is a frequent complaint in the working milieu of pain physicians. Common LBP generators are the lumbar spine, soft tissues around the spine, and intra-abdominal viscera; however, in recent times, lumbar spine ligament (LL) degeneration is increasingly getting more coverage as an important LBP source. Among various LLs, interspinous and supraspinatus ligaments' sprain-degeneration can perpetuate localized central LBP as described in the present case study. Localized LL sprain-degeneration in association with radiating LBP from prolapsed lumbar intervertebral disc (PLID) compressing adjacent nerve roots might further impair a patient's quality of life. In the present report, we describe both LL sprain-degeneration and PLID (a dual source of LBP) in a 26-year-old Bangladeshi woman; physicians often fail to notice this combination in their regular clinical practice.

FDG uptake observed around the lumbar spinous process: relevance to Baastrup disease

OBJECTIVE

In positron emission tomography (PET) with F-18-fluorodeoxyglucose (FDG), non-tumorous focal uptake is often observed around the lumbar spinous processes (LSPs). Close approximation of LSPs with sclerosis is often seen, which is called Baastrup disease. The aim of this study was to characterize this finding in terms of location and subjects' age and investigate the relation between PET and CT findings.

METHODS

The PET/CT scans of 40 patients each in the fifth, sixth, seventh, eighth, and ninth decades were screened for FDG uptake around the LSPs from L1-2 through L5-S1. Patients with metastasis to the lumbar spine or recent chemotherapy or rheumatoid arthritis-related disease were excluded. Focal uptake greater than blood pool activity was considered positive. Positive uptake was compared among the ages and locations. We also evaluated the relationship between FDG uptake and CT morphology.

RESULTS

Overall, focal uptake was observed in 122 LSPs in 71 patients. At least one positive uptake was seen in 9, 21, 15, 12, and 14 of 40 patients (16, 30, 30, 20, and 26 of 200 regions) in each age group of 40s through 80s, respectively (p = 0.12). As for the location, uptake around L1-2, L2-3, L3-4, L4-5, and L5-S1 was observed in 19, 22, 39, 35, and 7 regions, respectively (p < 0.01). There was no statistically significant difference in PET positivity among the five age groups, but positive uptake was predominantly seen in L3-4. Degeneration on CT was apparent in 58, 74, 108, 123, and 144 regions in each age group, respectively (p < 0.01), and in 38, 79, 131, 151, and 108 regions in each location, respectively (p < 0.01). The PET positive ratio was higher in CT positive group than in CT negative group (14 vs. 10 %, p < 0.05), but there was no significant difference of quantitative values (p = 0.10). Of 42 regions in 27 patients who had serial PET/CT scans that were initially PET-positive, 35 regions (83 %) turned negative on a later PET-scan.

CONCLUSIONS

Focal uptake around the LSPs was commonly seen in the mid-lumbar vertebrae, independent of age, and was not always correlated with morphological changes. This uptake should not be assumed to represent osseous metastasis.

Changes in pressure pain threshold in patients with chronic nonspecific low back pain

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

The purpose of this study is to compare pressure pain threshold (PPT) values between patients with chronic nonspecific low back pain (CLBP) and healthy individuals and correlate PPT values of the structures investigated with demographic and clinical data from patients with CLBP.

SUMMARY OF BACKGROUND DATA

Chronic pain may decrease pain tolerance of almost the entire spinal cord segment; however, previous studies on PPT in patients with low back pain have limited their focus to evaluating only patient complaints.

METHODS

Forty subjects participated in the study: 20 with a clinical diagnosis of CLBP and 20 healthy individuals. Outcome measures were PPT values of myotomes, sclerotomes, and dermatomes corresponding to segments L1 to S3; demographic, clinic, and social data; visual analogue scale, and Roland and Morris Questionnaire.

RESULTS

Most analyzed structures had lower PPT values in patients with CLBP than in healthy individuals on both sides (bilaterally). PPT correlated positively with height and pain duration (P < 0.05) and negatively with body mass index in the suprainterspinous ligament between L2 and L3 and dermatomes L5 to S2 (P < 0.05).

CONCLUSION

Our results showed that individuals with CLBP have lower PPT values than healthy individuals in almost all assessed structures. We propose a simple approach that can differentiate patients with CLBP whose hyperalgesia in the painful area may be the result of several mechanisms that should be further investigated, such as sensitization of the central nervous system.

LEVEL OF EVIDENCE

N/A.

Reprodutibilidade intra e interobservadores da classificação de Fujiwara para degeneração do ligamento interespinhoso por meio de ressonância magnética e relação entre as lesões degenerativas do disco intervertebral e do ligamento interespinhoso

OBJETIVO: avaliar a aplicabilidade da classificação de Fujiwara em uma análise intra e interobservadores e compará-la com a classificação de Pfirrmann. MÉTODOS: foram avaliados 87 ligamentos interespinhosos e discos intervertebrais de 29 pacientes (16 mulheres e 13 homens), com média de idade de 49 anos (24 a 78 anos), por meio da ressonância magnética pela classificação de Fujiwara e de Pfirrmann. A avaliação de Fujiwara foi realizada por três observadores, em duas ocasiões, com intervalo mínimo de 15 dias. A avaliação de Pfirrman foi realizada pelos três observadores em um único tempo. Utilizamos o índice de Kappa para comparar a variação intra e interobservadores. RESULTADOS: a concordância intraobservadores foi considerada boa; no entanto, a concordância interobservadores foi pobre, com índices de Kappa menores que 0,2. CONCLUSÃO: a classificação de Fujiwara não se mostrou reprodutiva para avaliação do ligamento interspinhoso. No entanto, a maior divulgação e utilização dessa classificação podem torná-la um bom instrumento de comparação entre resultados de diferentes estudos.