Imaging of Spondylodiscitis: A Comprehensive Updated Review-Multimodality Imaging Findings, Differential Diagnosis, and Specific Microorganisms Detection

Spondylodiscitis is defined by infectious conditions involving the vertebral column. The incidence of the disease has constantly increased over the last decades. Imaging plays a key role in each phase of the disease. Indeed, radiological tools are fundamental in (i) the initial diagnostic recognition of spondylodiscitis, (ii) the differentiation against inflammatory, degenerative, or calcific etiologies, (iii) the disease staging, as well as (iv) to provide clues to orient towards the microorganisms involved. This latter aim can be achieved with a mini-invasive procedure (e.g., CT-guided biopsy) or can be non-invasively supposed by the analysis of the CT, positron emission tomography (PET) CT, or MRI features displayed. Hence, this comprehensive review aims to summarize all the multimodality imaging features of spondylodiscitis. This, with the goal of serving as a reference for Physicians (infectious disease specialists, spine surgeons, radiologists) involved in the care of these patients. Nonetheless, this review article may offer starting points for future research articles.

Spondylodiscitis: A Diagnostic and Management Dilemma

Aims Spondylodiscitis (SpD), a debilitating infective condition of the spine, mandates early diagnosis and institution of appropriate therapy, for which accurate microbiology and histological evaluation of the affected tissue is vital. The objectives of the study were to assess the correlation between clinical and magnetic resonance imaging (MRI) findings with histopathology (HPE) and microbiology (MB) in clinically diagnosed spondylodiscitis. Settings and design This was a prospective study of 34 consecutive patients reporting at the outpatient department of a tertiary hospital with clinical and imaging features of SpD, who underwent image-guided/surgical biopsy of lesions. Methods and material The provisional diagnosis of SpD in all patients was made on the combined basis of clinical profile and MRI Spine findings. Tissue samples in all patients, obtained by either open surgery or CT-guided biopsy, were subjected to HPE and MB analysis.  Results SpD has a bimodal age distribution with the majority of patients being males in the fourth to fifth decades. Only raised erythrocyte sedimentation rate (ESR) was consistently seen amongst laboratory parameters, with leucocytosis being added pointer towards pyogenic etiology. MRI remained the imaging modality of choice for SpD but was not dependable for etiologic differentiation. On HPE and MB evaluations, 24 patients (71%) had findings consistent with infective SpD, while combined results augmented etiologic confirmation for 28 patients (82.4%). HPE was more sensitive than traditional MB methods to determine etiology in SpD, but the addition of the GeneXpert (Cepheid, Sunnyvale, California, United States) technique improved the MB positivity rate, especially in patients with tubercular SpD. Six patients (17.6%) with both negative HPE and MB results were categorized as 'Non-specific' SpD. Conclusions SpD poses a challenge to determine the etiology for the administration of specific antimicrobial therapy. A stratified standard institutional approach needs adoption to systematically evaluate SpD patients by having a high index of clinical suspicion, early imaging, followed by tissue biopsy for HPE and MB. Despite efforts to reach a diagnosis, a subset of patients without conclusive etiologic agent identification would remain as 'Non-specific', needing empiric antibiotic treatment based on clinico-radiologic profile.

Understanding the management of pediatric spondylodiscitis based on existing literature; a systematic review

BACKGROUND

Spondylodiscitis (SD), a rare disease in children, poses diagnostic challenges due to non-specific presenting symptoms, scarcity in incidence, and difficulty expressing pain in non-verbal children.

METHOD

A comprehensive search was conducted on three databases, including PubMed/Medline, Web of Science, and Scopus until March 2023. The inclusion criteria were studies that investigated the clinical characteristics, treatment, and complications of children's spondylodiscitis. Full text of cross-sectional and cohort studies were added. The quality assessment of cohort studies was conducted using the Newcastle-Ottawa Quality Assessment Scale. The search, screening, and data extraction were performed by two researchers independently.

RESULT

Clinical manifestations of discitis in children are nonspecific, such as back pain, fever, reduced ability or inability to walk or sit, limping, and reduced range of movements. The mean delay in the time of diagnosis was 4.8 weeks. The most affected site of all the studies was the lumbar spine. 94% of studies reported increased inflammatory markers such as white blood cell count, C-reactive protein, and erythrocyte sedimentation rate. Less than 30% of patients had positive blood cultures and biopsy findings. The most common microbiological results (64%) were Staphylococcus Aureus and Kingella kingae. In radiographic evaluation, intervertebral disk narrowing, lumbar lordosis reduction, loss of disk height, and destruction of the vertebral body have been reported. In all studies, antibiotic therapy was initiated; in 52% immobilization was employed, and 29% of studies reported surgery was performed, and the follow-up period differed from 1.5 months to 156 months. 94% of studies reported complications such as vertebral body destruction, back pain, kyphosis, reduced range of movement, scoliosis, and neurological complications.

CONCLUSION

Spondylodiscitis is an uncommon, heterogeneous, multifactorial disease with resulting difficult and delayed diagnosis. Due to its morbidity, it is essential to investigate children with refusal to walk, gait disturbances, or back pain, particularly when associated with elevated inflammatory markers.

Full Endoscopic Treatment for a Fibrosis Complication after Psoas Abscess

BACKGROUND

Psoas abscess is a challenging disease that may sometimes lead to a devastating prognosis. Early diagnosis and treatment are mandatory for better results in their treatments and to avoid complications.

PURPOSE

There is no article regarding a fibrosis treatment of the psoas muscle with a psoas abscess that is treated with full endoscopic debridement (FED).

STUDY DESIGN

a case report and literature review.

RESULT

we successfully treated this case, who suffered from psoas fibrosis with a clinical and MRI diagnosis, with full endoscopic debridement.

CONCLUSIONS

FED is a viable alternative to open debridement for this rare complication of a psoas muscle abscess.

The Epidemiology of Spondylodiscitis in Germany: A Descriptive Report of Incidence Rates, Pathogens, In-Hospital Mortality, and Hospital Stays between 2010 and 2020

BACKGROUND

Spondylodiscitis can lead to significant morbidity and mortality. Understanding its up-to-date epidemiological characteristics and trends is important to improve patient care.

METHODS

This study analyzed trends in the incidence rate of spondylodiscitis cases in Germany between 2010 and 2020, as well as the pathogens, in-hospital mortality rate, and length of hospital stay. Data were obtained from the Federal Statistical Office and the Institute for the Hospital Remuneration System database. The ICD-10 codes "M46.2-", "M46.3-" and "M46.4-" were evaluated.

RESULTS

The incidence rate of spondylodiscitis increased to 14.4/100,000 inhabitants, with 59.6% cases occurring in patients 70 years or older and affecting mainly the lumbar spine (56.2%). Absolute case numbers increased from 6886 by 41.6% to 9753 in 2020 (IIR = 1.39, 95% CI 0.62-3.08). Staphylococci and Escherichia coli were the most coded pathogens. The proportion of resistant pathogens was 12.9%. In-hospital mortality rates increased to a maximum of 64.7/1000 patients in 2020, intensive care unit treatment was documented in 2697 (27.7%) cases, and the length of stay per case was 22.3 days.

CONCLUSION

The sharply increasing incidence and in-hospital mortality rate of spondylodiscitis highlights the need for patient-centered therapy to improve patient outcomes, especially in the geriatric, frail population, which is prone to infectious diseases.

Polysegmental and multilevel lesions in hematogenous vertebral osteomyelitis: assessment of immediate and long-term results

Objective. To analyze the results of treatment of disseminated (polysegmental and multilevel) forms of hematogenous vertebral osteomyelitis (HVO) as compared with those of monosegmental and monovertebral lesions.

Material and Methods. A retrospective analysis of a monocenter cohort of 266 patients with hematogenous osteomyelitis of the spine for 2006 to 2019 was carried out. Patients were divided into two groups: Group A (polysegmental and multilevel lesions) included 33 (12.4 %) patients and Group B (monosegmental and monovertebral lesions) – 233 (87.6 %) patients. The main examination methods were: clinical, radiological (standardized roentgenography, CT), MRI, microbiological, histological and statistical ones.

Results. Comparison revealed that involvement of the cervical (p < 0.001) and thoracic (p = 0.014) spine was more typical for polysegmental and multilevel lesions. There was a tendency to the predominance of type A lesions according to the Pola classification in patients with local forms (p = 0.078) and to the increase in type C lesions in polysegmental and multilevel processes (p = 0.035). The number of neurological complications was higher in polysegmental and multilevel lesions (p = 0.003). There were no significant differences in the treatment results, the number of relapses and mortality rate between the compared groups.

Conclusion. Lesions of the cervical and thoracic spine and the presence of a neurological deterioration are typical for multilevel and polysegmental HVO. The formation of a multilevel lesion in different regions of the spine with a gap of 2–4 weeks or more requires a separate implementation of the diagnostic algorithm, defining of classification criteria and differentiated treatment tactics for each focus.

Post-COVID-19 Spondylodiscitis: A Case Study and Review of the Literature

COVID-19 is currently a major health problem, leading to respiratory, cardiovascular and neurological complications, with additional morbidity and mortality. Spinal infections are rare, representing around 1% of all bone infections and comprising less than 2 per 10,000 of all hospitalizations in tertiary care centers. Spondylodiscitis is a complex disease, with challenging diagnosis and management. We report the case of a 45-year-old man, non-smoker hospitalized for severe COVID-19 disease with respiratory failure. Post-COVID-19, in the 8th week after discharge, he was diagnosed by magnetic resonance imaging with spondylodiscitis, but etiology was not confirmed by microbiological investigations. Antibiotics were used, considering the identification of MRSA from cultures of pleural fluid and nasal swab, but surgical intervention was not provided. Clinic, biologic and imagistic were improved, but rehabilitation and long term follow up are necessary. We concluded that spondylodiscitis with spinal abscess is a rare but severe complication post-COVID-19 disease, due to dysbalanced immune response related to the respiratory viral infection, endothelial lesions, hypercoagulation and bacterial superinfection.

Noncontiguous Multifocal Spondylodiscitis in 3 Regions of the Spine

Spondylodiscitis is an uncommon infectious disease of the spine, usually presenting in 1 or 2 contiguous levels, associated with risk factors such as diabetes, intravenous drugs, corticosteroids, and invasive procedures. The most common presentation is pain with nonspecific systemic manifestations. Diagnosis relies on clinical suspicion, laboratories, and imaging studies. Urgent treatment is important due to the high morbid mortality associated with sepsis or a fulminant disease course. We report the case of a 39-year-old female diagnosed with noncontiguous multifocal spondylodiscitis, in the cervical, thoracic, and lumbar spine. The patient initially presented with back pain, inability to walk and severe neurological deficit in the upper and lower extremities, upon diagnosis broad-spectrum antibiotics were initiated. A staged surgical approach was performed in the 3 spine segments. During the 6 month follow-up, the patient presented walking with assistance, with the recovery of strength in the upper and lower extremities.

Surgical Management of Lumbar Hardware Failure Due to Recurrent Postoperative Spondylodiscitis: Case Report

Spondylodiscitis is a rare bacterial infection of the vertebrae and intervertebral discs that causes inflammation and follows a destructive course. When conservative management fails, surgical management requires immediate debridement of the infective focus, with decompression and stabilization through a ventral approach. The most frequently involved locations are the lumbar spine (58%), thoracic (30%), and cervical (11%) regions. Gram-positive organisms such as Staphylococcus aureus and Streptococcus species are the most commonly isolated organisms (67% and 24%, respectively). Pathophysiologically, infectious spondylodiscitis begins in the anterior portion of the vertebral body, due to its rich vascular supply, and then spreads to the rest of the vertebral body and along the medullary spaces. In this study, we report the management of recurrent lumbar postoperative spondylodiscitis with transforaminal lumbar interbody fusion (TLIF) hardware failure in a 62-year-old female.

Cases report: spondylodiscitis and epiduritis after suffering COVID - 19

Background. The review analyzes a possible rare complication of COVID-19 in the form of spondylodiscitis, including with developed epiduritis, in patients who have undergone COVID-19 with severe pneumonia, respiratory failure and systemic inflammatory response syndrome (SIRS). Clinical Case Description. Based on our own clinical observations, an approach to the diagnosis and treatment of three patients is described, each of whom had SIRS, severe fever, a significant increase in laboratory markers of inflammation (C - reactive protein (CRP), leukocytosis, erythrocyte sedimentation rate (ESR), fibrinogen, procalcitonin , ferretin), the addition of bacterial pneumonia, pronounced disorders of coagulation hemostasis, the development of spondylodiscitis, despite the wide range of previous antibiotic therapy, acute pain in the lumbar spine (LSP) with features of "red flags". In the first patient, against the background of massive antibiotic therapy, revisions of purulent foci, glucocorticosteroid (GCS) therapy, and surgical treatment, there was a significant positive trend in the form of pain relief. The second patient showed positive dynamics against the background of conservative antibiotic therapy. The third patient, with a paravertebral abscess at the level of developed spondylodiscitis, received massive antibiotic therapy in combination with GCS, and was operated on to decompress the spinal cord. Conclusion. The authors note that spondylodiscitis and epiduritis may be some of the possible complications of COVID-19 and / or the result of the unwanted action of drugs used to treat this disease. In this regard, timely diagnosis and treatment of this pathology in COVID - 19 seems to be very relevant

The Induced Immune Response in Patients With Infectious Spondylodiscitis: A Prospective Observational Cohort Study

Introduction

Infectious spondylodiscitis is a rare infection of the intervertebral disc and the adjacent vertebral bodies that often disseminates and requires long-term antibiotic therapy. Immunologic profiling of patients with infectious spondylodiscitis could allow for a personalized medicine strategy. We aimed to examine the induced immune response in patients with infectious spondylodiscitis during and after antibiotic therapy. Furthermore, we explored potential differences in the induced immune response depending on the causative pathogen and the dissemination of the disease.

Methods

This was a prospective observational cohort study that enrolled patients with infectious spondylodiscitis between February 2018 and August 2020. A blood sample was collected at baseline, after four to six weeks of antibiotic therapy (during antibiotic therapy), and three to seven months after end of antibiotic therapy (post-infection). The induced immune response was assessed using the standardized functional immune assay TruCulture^®. We used a panel of three immune cell stimuli (lipopolysaccharide, Resiquimod and polyinosinic:polycytodylic acid) and an unstimulated control. For each stimulus, the induced immune response was assessed by measuring the released concentration of Interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12p40, IL-17A, Interferon-γ (IFN-γ) and Tumor necrosis factor-α (TNF-α) in pg/mL.

Results

In total, 49 patients with infectious spondylodiscitis were included. The induced immune responses were generally lower than references at baseline, but the cytokine release increased in patients after treatment with antibiotic therapy. Post-infection, most of the released cytokine concentrations were within the reference range. No significant differences in the induced immune responses based on stratification according to the causative pathogen or dissemination of disease were found.

Conclusion

We found lower induced immune responses in patients with infectious spondylodiscitis at baseline. However, post-infection, the immune function normalized, indicating that an underlying immune deficiency is not a prominent factor for spondylodiscitis. We did not find evidence to support the use of induced immune responses as a tool for prediction of the causative pathogen or disease dissemination, and other methods should be explored to guide optimal treatment of patients with infectious spondylodiscitis.

Severity and Outcome of Neurologic Deficits in Patients with Pyogenic Spondylodiscitis: A Systematic Review

Patients with advanced pyogenic spondylodiscitis can present with neurologic deficits. However, the prevalence, severity, and outcome of the neurologic deficits are not well known. A systematic review was performed to improve the knowledge of this commonly encountered clinical scenario. The considerable number of severe neurologic deficits in addition to their poor recovery, even after surgical intervention, demonstrates that the early diagnosis of pyogenic spondylodiscitis is crucial. Prompt surgical intervention is likely associated with a greater chance of improvement of neurologic status than nonsurgical treatment.

MORPHOLOGICAL ASPECT OF PYOGENIC SPINAL EPIDURAL ABSCESSES. PART I

ABSTRACT Background: Pyogenic Spinal Epidural Abscess (PSEA) is difficult to diagnose and can have devastating consequences. Magnetic Resonance Imaging (MRI) has high sensitivity and specificity, which are further increased with the use of contrast. There are several classifications of vertebral infectious processes, with emphasis on spondylodiscitis. Objective: To analyze the morphological parameters and their reproducibility; and to analyze different resonance imaging sequences. Methods: Using an image database, a morphological classification of PSEA was planned, with five parameters: Region (R), indicating the upper and lower limits of the abscess; Location (U), indicating whether the abscess is anterior or posterior within the canal; Compromise (C), meningeal or content of the structures; Association (A), discitis, osteomyelitis or both; and Perivertebral (P), anterior, lateral or posterior extravertebral abscess. The first three parameters give an idea of the volume of the PSEA, while the last two give the related infectious foci. Thirty-five cases were analyzed using Kappa’s coefficient. Results: The global intra- and interobserver reproducibility was Kappa 0.81. The results for each parameter were as follows: R=0.95, U=0.92, C=0.66, A=0.70 and P=0.80. The first three give a notion of volume and the last two relate to the presence of vertebral infectious foci outside the canal. T2 weighted MRI with contrast was found to be the most effective imaging sequence. Conclusion: The morphological classification is simple to use, with excellent reproducibility. The parameters with the highest reproducibility were region and location, with values >0.92. The addition of gadolinium contrast increased the sensitivity of the diagnosis; the use of sagittal and axial images in T2-MRI was the most sensitive imaging sequence. Evidence Level III; Original.

Spinal disorders mimicking infection

Spinal infections are very commonly encountered by radiologists in their routine clinical practice. In case of typical MRI features, the diagnosis is relatively easy to interpret, all the more so if the clinical and laboratory findings are in agreement with the radiological findings. In many cases, the radiologist is able to make the right diagnosis, thereby avoiding a disco-vertebral biopsy, which is technically challenging and associated with a risk of negative results. However, several diseases mimic similar patterns, such as degenerative changes (Modic) and crystal-induced discopathy. Differentiation between these diagnoses relies on imaging changes in endplate contours as well as in disc signal. This review sought to illustrate the imaging pattern of spinal diseases mimicking an infection and to define characteristic MRI and CT patterns allowing to distinguish between these different disco-vertebral disorders. The contribution of advanced techniques, such as DWI and dual-energy CT (DECT) is also discussed.

Pyogenic and Non-Pyogenic Spinal Infections: Diagnosis and Treatment

Spinal infection (SI) is an infection of vertebral bodies, intervening disc, and/or adjoining para-spinal tissue. It represents less than 10 % of all skeletal infections. There are numerous factors that predispose to developing a SI. Due to the low specificity of signs, delayed diagnosis is common. Hence, SI may be associated with poor outcomes. Diagnosis of SI must be supported by clinicopathological and radiological findings. MRI is a reliable modality of choice. Treatment options vary according to the site of the infection, disease progression, neurology, presence of instability, and general condition of the subject. Conservative treatment (orthosis/ bed-rest + antibiotics) is recommended during the early course with no/ lesser degree of neurological involvement and to medically unfit patients. Nevertheless, when conservative measures alone fail, surgical interventions must be considered. The use of concomitant antimicrobial drugs intravenously during initial duration followed by oral administration is a necessity. Controversies exist regarding the optimal duration of antimicrobial therapy, yet never given less than six weeks. Heterogeneity in clinical picture and associated co-morbidities with a range of treatment modalities are available; however, a common applicable guideline for SI does not exist. Managing SI must be tailored on a case-to-case basis.

[Coexistent septic arthritis and spondylodiscitis as important differential diagnosis in immunosuppressed patients]

Die septische Arthritis und Spondylodiszitis stellen bei immunsupprimierten Patienten eine wichtige Differenzialdiagnose des Gelenk- oder Wirbelsäulenschmerzes dar. Hierbei kommt es zu einem Erregerbefall eines Gelenks bzw. einer Bandscheibe und angrenzender Wirbelkörper. Es zeigen sich meist unspezifische Symptome wie lokaler Gelenk- oder Rückenschmerz, Fieber und verringerter Allgemeinzustand. Diagnostisch kann bei klinischem Verdacht die bakterielle Besiedelung durch eine Gelenkpunktion und Blutkulturen nachgewiesen werden. Zur Diagnosefindung einer Spondylodiszitis sollte eine bildmorphologische Darstellung mittels Magnetresonanztomographie erfolgen. Neben einer adäquaten Schmerztherapie und empirischer antibiotischer Therapie sollte bei einer septischen Arthritis die chirurgische Entfernung des infektiösen Materials aus dem Gelenk angestrebt werden. Eine chirurgische Versorgung der Spondylodiszitis sollte bei auftretenden Komplikationen erfolgen. Die folgende Kasuistik stellt den gleichzeitigen Befund einer septischen Polyarthritis und Spondylodiszitis bei einem immunsupprimierten Patienten mit HIV-Infektion vor und zeigt eindrücklich das Auftreten von Komplikationen bei Verzögerung einer adäquaten Therapie.

Tuberculous and Brucellar Spondylodiscitis: Comparative Analysis of Clinical, Laboratory, and Radiological Features

Study Design

This was a retrospective study.

Purpose

The aim was to compare the clinical, laboratory, radiological, and evolutionary features of tuberculous spondylodiscitis (TS) and brucellar spondylodiscitis (BS).

Overview of Literature

Clinical presentation of spondylodiscitis varies according to the underlying etiology, among which brucellosis and tuberculosis represent the primary cause, in endemic countries. Only a few studies have compared the characteristics between TS and BS.

Methods

A retrospective study was conducted using the data of all patients hospitalized for TS and BS in the infectious diseases department between 1991 and 2018.

Results

Among a total of 117 patients, 73 had TS (62.4%) and 44 had BS (37.6%). Females were significantly more affected with TS than males (56.2% vs. 22.7%, p<0.001). Fever (72.7% vs. 45.2%, p=0.004) and sweating (72.7% vs. 47.9%, p=0.009) were significantly more frequent among patients with BS. The median erythrocyte sedimentation rate was significantly higher in the TS group (median, 70 mm/hr; interquartile range [IQR], 45–103 mm/hr) than in the BS group (median, 50 mm/hr; IQR, 16–75 mm/hr) (p=0.003). Thoracic involvement was significantly more frequent in the TS group (53.4% vs. 34.1%, p=0.04), whereas lumbar involvement was significantly more frequent in the BS group (72.7% vs. 49.3%, p=0.01). Initial imaging findings revealed significantly higher frequencies of posterior vertebral arch involvement, vertebral compaction, and spinal cord compression in the TS group. Percutaneous abscess drainage (20.5% vs. 2.3%, p=0.005) and surgical treatment (17.8% vs. 2.3%, p=0.01) were more frequently indicated in the TS group, with a significant difference.

Conclusions

A combination of clinical, laboratory, and radiological features can be used to distinguish between TS and BS while these patients await diagnosis confirmation.

Full-endoscopic debridement and drainage treating spine infection and psoas muscle abscess

Background

In recent years, full-endoscopic debridement and drainage (FEDD) is gaining popularity treating spondylodiscitis. Comparing to tradition open surgery, FEDD possess many advantages including lower anesthesia risk and minimally invasiveness. In this study, we report our surgical technique of FEDD and preliminary clinical outcome in 34 consecutive patients with minimum 12 months follow-up.

Methods

In our institute, "early intervention and minimally invasive surgery" is our primary strategy to treat spine infection. Surgical approaches of FEDD include transforaminal and interlaminar technique. Selection of surgical approach depends on the location of spine infection. "Trocar-rotating technique" is a novel method to treat psoas muscle abscess. Additional instrumentation is suggested in complicated patients with unstable spinal segment.

Results

Since June 2016 to June 2018, 34 patients including 22 males and 12 females with average aged 62.3 years (21 to 82 years old) sustained spine infection were treated by FEDD. Twenty-eight patients belong to primary spondylodiscitis and 15 patients among them sustained concomitant psoas abscess. Five patients was post-operative infection and one patient was mixed infection including lumbar spondylodiscitis, psoas abscess and multi-level posterior epidural abscess. Positive culture was obtained in 27 patients (27/34=79%) while gram-positive cocci (Staphyloccocci and Streptoccoi) are the most frequent pathogen (67%). Infection was controlled in 28 patients (28/34=82%). Six patients were defined as treatment failure with infection recurrence, they underwent repeat FEDD surgery or open revision surgeries. There was no major intra-operative complications expect two patients sustained transient paresthesia and one instrument broken. Superficial wound infection was encountered in 2 patients and healed after local debridement.

Conclusions

FEDD is a safe and effective procedure. We hope that, FEDD surgery will be the first-line surgery method to treat lumbar spine infection globally in the near future.

[Which factors influence the inpatient course for patients with spondylodiscitis?]

BACKGROUND

Spondylodiscitis is a rare disease with an increasing incidence.

METHODS

In this retrospective study 112 patients with spondylodiscitis surgically treated from 1 January 2005 to 31 December 2012 in a level I spine center were investigated with respect to potential prognostic criteria. The time period covered by the investigation was the duration of hospitalization. The parameters analyzed were mortality, age, localization of the spondylodiscitis, detection of abscesses and pathogens, neurological status and body mass index (BMI).

RESULTS

The average age of the patients was 68.3 years (±12.9 years). The mortality rate during hospitalization was 10.7% (N = 12). Older patients had a significantly higher in-hospital mortality rate (p = 0.008). Abscess formation was found in 49.1% of the patients and was associated with a significantly longer hospital stay (p = 0.001) and in the intensive care unit (ICU, p = 0.001) as well as a higher risk of revision surgery (p = 0.018). In addition, obese patients had a significantly higher occurrence of abscesses (p = 0.034). Pathogen detection was successful in 60.7 % of the cases with Staphylococcus aureus as the most frequent pathogen. Detection of pathogens was associated with a longer hospital stay (p = 0.006) and a greater need of intensive care monitoring (p = 0.017). Patients with a nephropathy had a significantly increased mortality, longer duration of hospitalization and a more frequent occurrence of multilevel afflictions.

CONCLUSION

Old age, abscess formation, positive detection of pathogens and renal failure can be used as prognostic criteria. Risk factors for formation of abscesses include a lumbar localization of spondylodiscitis, nephropathy as well as detection of a pathogen and obesity.

Impact of MRI, CT, and Clinical Characteristics on Microbial Pathogen Detection Using CT-Guided Biopsy for Suspected Spondylodiscitis

Spondylodiscitis accounts for 2–7% of osteomyelitis cases and is characterized by pain, systemic inflammation, and permanent neurological deficits. We aimed to identify imaging characteristics and clinical parameters to successfully predict microbiological pathogens by computed tomography (CT)-guided biopsy in suspected spondylodiscitis cases. Forty consecutive patients (mean age 65.1 years) with suspected spondylodiscitis underwent CT-guided biopsy. CT features (non-sclerotic endplate erosions (NSEs)), magnetic resonance criteria (paravertebral/epidural abscess (PA/EA) formation), and clinical data (C-reactive protein (CRP) > 50 mg/L) were assessed for their predictive potential. NSEs were detected in 6/11 (54.5%) and 1/29(3.4%) patients with positive and negative microbiology, respectively. PA and EA, respectively, were present in 7/11(63.6%) and 3/11 patients with positive microbiology and 7/29 (24.1%) and 2/29 patients with negative microbiology. CRP > 50 was observed in 7/11 (63.6%) and in 7/29 (24.1%) patients with positive and negative microbiology, respectively. Three double combinations possessed near-perfect specificity (PA + NSE, 100%; PA + CRP > 50, 96.6%; NSE + CRP > 50, 96.6%). The top three Youden indices included combinations with NSE. Since CT/magnetic resonance (MR) imaging and CRP are routinely used to evaluate spondylodiscitis, the presented diagnostic criteria and combinations can aid decision-making for biopsy.

The role of histology in the diagnosis of spondylodiscitis

Aims

The aim of this study was to determine the diagnostic utility of histological analysis in spinal biopsies for spondylodiscitis (SD).

Patients and Methods

Clinical features, radiology, results of microbiology, histology, and laboratory investigations in 50 suspected SD patients were evaluated. In 29 patients, the final (i.e. treatment-based) diagnosis was pyogenic SD; in seven patients, the final diagnosis was mycobacterial SD. In pyogenic SD, the neutrophil polymorph (NP) infiltrate was scored semi-quantitatively by determining the mean number of NPs per (×400) high-power field (HPF).

Results

Of the 29 pyogenic SD patients, 17 had positive microbiology and 21 positive histology (i.e. one or more NPs per HPF on average). All non-SD patients showed less than one NP per HPF. The presence of one or more NPs per HPF had a diagnostic sensitivity of 72.4%, specificity 100%, accuracy 100%, positive predictive value (PPV) 81.0%, and negative predictive value (NPV) 61.9%. Sensitivity, specificity, and accuracy were greater using the criterion of positive histology and/or microbiology than positive histology or microbiology alone. Granulomas were identified histologically in seven mycobacterial SD patients, and positive microbiology was detected in four.

Conclusion

The diagnosis of pyogenic SD was more often confirmed by positive histology (one or more NPs per HPF on average) than by microbiology, although diagnostic sensitivity was greater when both histology and microbiology were positive. Cite this article: Bone Joint J 2019;101-B:246–252.

Utility of the claw sign in spine magnetic nuclear resonance with diffusion to differentiate Modic type I changes for degenerative disease versus infection

BACKGROUND

In 1988, Modic and his colleagues described changes in the subchondral bone marrow of the vertebral plates in patients with degenerative disease or other pathologies, which were observed in the nuclear magnetic resonance (NMR) of the spine and were subdivided into three patterns of signal changes, called Modic type I, Modic type II and Modic type III. The main differential diagnosis of the Modic I changes of the vertebral plates due to degenerative disease in spine NMR, is infection in its early stages. In their study in 2014, Patel and collaborators, using a protocol and the concept of diffusion in spine MRI, were able to demonstrate that by means of the "claw sing", a degenerative disease with Modic type I changes, can be differentiated from an infection in early stages. In this series of cases, the algorithm used by Patel et al. was implemented.

METHODS

The clinical records of patients who consulted the emergency department for lumbar pain without clear etiology, between January 1, 2017 and December 31, 2017, were analyzed. Due to axial lumbar pain, subjects were hospitalized and studies were ordered, including contrasted MRI of the lumbosacral spine. Then, with laboratory tests and MRI findings of Modic type I changes, it was not possible to differentiate between degenerative disease vs. spondylodiscitis. Therefore, the algorithm used in the study by Patel and collaborators was applied.

RESULTS

There were 13 patients identified with lumbar or dorsal pain over 3 months of evolution, with nonspecific symptoms; 5 patients (38.46%) reported arterial hypertension, 4 patients (30.77%) diabetes mellitus, and 4 patients (30.77%) chronic kidney disease stage V in management with hemodialysis, 3 patients (23.08%) presented immunosuppressive conditions and 3 patients (23.08%) had a history of spinal surgery with instrumentation. All the patients were hospitalized and a lumbosacral and thoracic spine simple MRI was performed with Modic type I changes to perform contrast-enhanced MRI with diffusion and ADC. From the 13 cases studied for low back pain, there were 7 patients (53.85%) with confirmed findings of Modic type I changes due to degenerative disease for presenting claw sign in spinal MRI diffusion and 6 patients (46.15%) Modic type changes I due to infection in the absence of a claw sign in the column MRI diffusion.

CONCLUSIONS

Spinal column MRI with diffusion is useful to differentiate patients with type I changes due to degenerative disease with positive claw sign; of patients with type I changes due to infection with absent claw sign. In addition, in patients with compromised renal function, column MRI with diffusion without contrast could be a diagnostic alternative, since it does not require contrast media to confirm infection.