Extravertebral low back pain: a scoping review

BACKGROUND

Low back pain (LBP) is one of the most common reasons for consultation in general practice. Currently, LBP is categorised into specific and non-specific causes. However, extravertebral causes, such as abdominal aortic aneurysm or pancreatitis, are not being considered.

METHODS

A systematic literature search was performed across MEDLINE, Embase, and the Cochrane library, complemented by a handsearch. Studies conducted between 1 January 2001 and 31 December 2020, where LBP was the main symptom, were included.

RESULTS

The literature search identified 6040 studies, from which duplicates were removed, leaving 4105 studies for title and abstract screening. Subsequently, 265 publications were selected for inclusion, with an additional 197 publications identified through the handsearch. The majority of the studies were case reports and case series, predominantly originating from specialised care settings. A clear distinction between vertebral or rare causes of LBP was not always possible. A range of diseases were identified as potential extravertebral causes of LBP, encompassing gynaecological, urological, vascular, systemic, and gastrointestinal diseases. Notably, guidelines exhibited inconsistencies in addressing extravertebral causes.

DISCUSSION

Prior to this review, there has been no systematic investigation into extravertebral causes of LBP. Although these causes are rare, the absence of robust and reliable epidemiological data hinders a comprehensive understanding, as well as the lack of standardised protocols, which contributes to a lack of accurate description of indicative symptoms. While there are certain disease-specific characteristics, such as non-mechanical or cyclical LBP, and atypical accompanying symptoms like fever, abdominal pain, or leg swelling, that may suggest extravertebral causes, it is important to recognise that these features are not universally present in every patient.

CONCLUSION

The differential diagnosis of extravertebral LBP is extensive with relatively low prevalence rates dependent on the clinical setting. Clinicians should maintain a high index of suspicion for extravertebral aetiologies, especially in patients presenting with atypical accompanying symptoms.

Heterogeneous Characteristics of Patients with Inflammatory Abdominal Aortic Aneurysm. Systematic Review of Therapeutic Solutions

BACKGROUND

Endovascular repair of inflammatory abdominal aortic aneurysms (IAAAs) has emerged as an alternative to open surgery, but direct comparisons are limited. The aim of the study was to compare clinical outcomes of endovascular and open repair for IAAA according with specific clinical characteristics.

METHODS

We performed a literature review of reports describing patients who had open or endovascular repair for IAAA. A literature search was performed in June 2022 by 2 investigators who conducted a review of papers reported in PubMed, Embase, MEDLINE, and Cochrane Database. The strings "Inflammatory aneurysm" and "Abdominal Aortic Aneurysms" were used. There was no language restriction and screened reports were published from March 1972 to December 2021. We identified 2,062 patients who had open (1,586) or endovascular repair (476) for IAAA. Primary outcomes were operative mortality and morbidity. Secondary outcomes were complications during follow-up (mean follow-up: 48 months). Propensity score matching was performed between patients who had open or endovascular surgery.

RESULTS

In Western countries, propensity-weighted postoperative mortality (in-hospital) (1.5% endovascular vs. 6% open) and morbidity rates (6% vs. 18%) were significantly lower in patients who had endovascular repair (P < 0.0001); patients with larger aneurysm (more than 7 cm diameter), signs of active inflammation, and retroperitoneal rupture of the aneurysm had better outcomes after endovascular repair than after open surgery. Hydronephrosis was present in 20% of the patients. Hydronephrosis regressed in most patients when signs of active inflammation were present suggesting an acute onset of the hydronephrosis itself (fever, elevated serum C Reactive Protein) either after endovascular or open surgery. Long-standing hydronephrosis as suggested by the absence of signs of active inflammation rarely regressed after endovascular surgery despite associated steroid therapy. During a mean follow-up of 48 months, propensity-weighted graft-related complications were more common in patients who had endovascular repair (20% vs. 8%). For patients from Asia, short-term and medium-term results were similar after open and endovascular repair. IAAAs related with aortitis were more common in Asia. In Western countries, IAAAs were commonly associated with atherosclerosis.

CONCLUSIONS

Patients with IAAA represent a heterogeneous population, suggesting biological differences from continent to continent; conservative therapy and endovascular or open surgery should be chosen according to the patient clinical condition. Endovascular repair presents advantages in patients with signs of active inflammation and contained rupture of the IAAA and larger aneurysms. Hydronephrosis, without signs of active inflammation, rarely regresses after endovascular repair associated with steroid therapy. Further studies are needed to establish the long-term results of endovascular repair.

Exploring the Effect and Mechanism of Si-Miao-Yong-An Decoction on Abdominal Aortic Aneurysm Based on Mice Experiment and Bioinformatics Analysis

Background

Abdominal aortic aneurysm (AAA) is a fatal disease characterized by high morbidity and mortality in old population. Globally, effective drugs for AAA are still limited. Si-Miao-Yong-An decoction (SMYAD), a traditional Chinese medicine (TCM) formula with a high medical value, was reported to be successfully used in an old AAA patient. Thus, we reason that SMYAD may serve as a potential anti-AAA regime.

Objective

The exact effects and detailed mechanisms of SMYAD on AAA were explored by using the experimental study and bioinformatics analysis.

Methods

Firstly, C57BL/6N mice induced by Bap and Ang II were utilized to reproduce the AAA model, and the effects of SMYAD were systematically assessed according to histology, immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA). Then, network pharmacology was applied to identify the biological processes, pathways, and hub targets of SMYAD against AAA; moreover, molecular docking was utilized to identify the binding ability and action targets.

Results

In an animal experiment, SMYAD was found to effectively alleviate the degree of pathological expansion of abdominal aorta and reduce the incidence of Bap/Ang II-induced AAA, along with reducing the damage to elastic lamella, attenuating infiltration of macrophage, and lowering the circulating IL-6 level corresponding to the animal study, and network pharmacology revealed the detailed mechanisms of SMYAD on AAA that were related to pathways of inflammatory response, defense response, apoptotic, cell migration and adhesion, and reactive oxygen species metabolic process. Then, seven targets, IL-6, TNF, HSP90AA1, RELA, PTGS2, ESR1, and MMP9, were identified as hub targets of SMYAD against AAA. Furthermore, molecular docking verification revealed that the active compounds of SMYAD had good binding ability and clear binding site with core targets related to AAA formation.

Conclusion

SMYAD can suppress AAA development through multicompound, multitarget, and multipathway, which provides a research direction for further study.

Open Versus Endovascular Repair of Inflammatory Abdominal Aortic Aneurysms

Objectives:

Open surgical repair (OSR) of inflammatory abdominal aortic aneurysms (IAAAs) can have significant morbidity. The aim of the present investigation was to compare IAAA outcome after OSR and endovascular aneurysm repair (EVAR) and perform a meta-analysis of the literature.

Methods:

Twenty-seven patients with an intact IAAA operated on during a 21-year period were included.

Results:

Nine patients were managed with EVAR and 18 with OSR. In the EVAR group, the number of transfused red blood cell units ( P = .001), procedure duration ( P < .001), and postoperative hospitalization ( P = .004) were significantly reduced compared to OSR. A trend for decreased morbidity with EVAR (11% vs 33% for OSR, P = .36) was observed. On literature review and meta-analysis, morbidity after EVAR was 8.3%, significantly lower compared to OSR (27.4%, P = .047). Mortality for nonruptured IAAAs was 0% after EVAR and 3.6% after OSR ( P = 1.00).

Conclusions:

Endovascular aneurysm repair of IAAAs is associated with decreased procedure duration, transfusion needs, hospitalization, and morbidity compared to OSR.

Exploration of the mechanisms by which 3,4-benzopyrene promotes angiotensin II-induced abdominal aortic aneurysm formation in mice

OBJECTIVE

This study examined the influence of 3,4-benzopyrene (BaP), a compound found in cigarette smoke, on the formation of angiotensin II (Ang II)-induced abdominal aortic aneurysm (AAA) formation in mice and the underlying mechanisms.

METHODS

C57/B6n mice were divided into four groups. The control group received a weekly intraperitoneal injection of medium-chain triglycerides. The Ang II group received a daily Ang II infusion (0.72 mg/kg) and a weekly intraperitoneal injection of medium-chain triglycerides. The Ang II/BaP group received a daily Ang II infusion (0.72 mg/kg) and a weekly intraperitoneal BaP injection (10 mg/kg, dissolved in medium-chain triglycerides). The BaP group received a weekly intraperitoneal BaP injection (10 mg/kg). After 5 weeks, abdominal aortic diameter was determined. Aortic tissues underwent hematoxylin and eosin, Masson, and immunochemistry staining for evaluation of vascular wall structure, collagen, macrophage infiltration, matrix metalloproteinases (MMPs), and apoptosis.

RESULTS

The Ang II infusion and BaP injection induced AAAs in 41.67% of mice vs 25% in the Ang II group (P < .05). The average aortic diameter increased in the Ang II/BaP group compared with the Ang II group (1.40 ± 0.25 vs 1.2 ± 0.23 mm; P < .05). Average aortic muscular cell apoptosis was higher in the Ang II/BaP group (31% ± 12%) than in the Ang II (19% ± 5%; P < .05) or BaP groups (23% ± 4%; P < .05). Aortic macrophage infiltration and expression of MMP-2, MMP-9, MMP-12, and nuclear factor-κB increased (0.56 ± 0.12, 0.47 ± 0.13, 0.49 ± 0.14, 0.49 ± 0.11, and 0.42 ± 0.12, respectively) in the Ang II/BaP group compared with the Ang II group (0.27 ± 0.08, 0.25 ± 0.06, 0.24 ± 0.09, 0.24 ± 0.09, and 0.23 ± 0.06, respectively; P < .05 for all).

CONCLUSIONS

BaP promotes Ang II-induced AAA formation in mice via elevating infiltration of macrophages, activating nuclear factor-κB, upregulating the expression of MMP-2, MMP-9, and MMP-12, and increasing the apoptosis of vascular muscle cells in its synergistic effect with Ang II in aortic wall.

Smooth muscle cells isolated from thoracic aortic aneurysms exhibit increased genomic damage, but similar tendency for apoptosis

Aortic aneurysms (AA) are characterized by structural deterioration leading to progressive dilation. During the development of AA, two key structural changes are pronounced, one being degradation of extracellular matrix and the other loss of smooth muscle cells (SMCs) through apoptosis. Reactive oxygen species (ROS) are produced above physiological levels in dilated (aneurismal) part of the aorta compared to the nondilated part and they are known to be associated with both the extracellular matrix degradation and the loss of SMCs. In this study, we hypothesized that aneurismal SMCs are more prone to apoptosis and that at least some cells undergo apoptosis due to elevated ROS in the aortic wall. To test this hypothesis, we first isolated SMCs from thoracic aneurismal tissue and compared their apoptotic tendency with normal SMCs in response to H(2)O(2), oxidized sterol, or UV treatment. Exposed cells exhibited morphological changes characteristic of apoptosis, such as cell shrinkage, membrane blebbing, chromatin condensation, and DNA fragmentation. Terminal deoxynucleotidyl transferased UTP nick end labeling (TUNEL) further confirmed the fragmentation of nuclear DNA in these cells. Vascular SMCs were analyzed for their micronuclei (MN) and binucleate (BN) frequency as indicators of genomic abnormality. These data were then compared to patient parameters, including age, gender, hypertension, or aortic diameter for existing correlations. While the tendency for apoptosis was not significantly different compared to normal cells, both the %MN and %BN were higher in aneurismal SMCs. The data suggest that there is increased DNA damage in TAA samples, which might play a pivotal role in disease development.

IgG4-related inflammatory abdominal aortic aneurysm

PURPOSE OF REVIEW

IgG4-related systemic disease is a recently proposed entity characterized by high serum IgG4 concentrations, sclerosing inflammation containing numerous IgG4-positive plasmacytes, dramatic responsiveness to steroid therapy, and occurrence of multiple organs. This review described that some cases of inflammatory abdominal aortic aneurysm (IAAA) have similar clinicopathological features that are now considered to represent aortic lesions of IgG4-related systemic disease under the concept of IgG4-related IAAA.

RECENT FINDINGS

IgG4-related IAAA is characterized by high serum IgG4 and immunoglobulin E levels, high titers of antinuclear antibodies, and high prevalence of allergic disorders such as bronchial asthma. The patients show a risk of developing IgG4-related systemic diseases in other organs during their life. Histologically, sclerosing inflammation containing numerous IgG4-positive plasmacytes is observed predominantly in the adventitia. Similar lesions have also been reported in the thoracic aorta and large arteries.

SUMMARY

Recognition of the fact that IgG4-related systemic disease could involve the vascular lesions offers potential new management of those. However, only 3 years have passed since the first report of IgG4-related IAAA. Further studies are necessary to elucidate other vascular lesions associated with IgG4-related systemic disease, the usefulness of steroid therapy for the management of IgG4-IAAA, and underlying pathological and immunological characteristics.