Percutaneous needle biopsy in diagnosis and identification of causative organisms in cases of suspected vertebral osteomyelitis

Diagnostic efficacy and clinical impact of image-guided core needle biopsy of suspected vertebral osteomyelitis

OBJECTIVES

The diagnostic yield and clinical impact of image-guided core needle biopsy (ICNB) of suspected vertebral osteomyelitis in adults is heterogenous in published studies owing to small sample sizes, indicating the need for large cohort studies.

METHODS

A retrospective analysis of ICNBs was performed from 2010 to 2021 for patients with imaging findings consistent with vertebral osteomyelitis. For each biopsy, a series of factors were analyzed, as well as if histopathology was diagnostic of osteomyelitis and if microbiological cultures were positive. In addition, it was recorded in what way biopsy influenced clinical management regarding antimicrobial treatment. A multivariate statistical analysis was performed to evaluate the factors associated with yield.

RESULTS

A total of 570 biopsies performed on 527 patients were included. A histopathologic diagnosis of osteomyelitis was made in 68.4% (359 of 525) of biopsies, and microbiological cultures were positive in 29.6% (169 of 570). Elevated erythrocyte sedimentation rate was positively associated with a histopathologic diagnosis of osteomyelitis (odds ratio [OR] =1.96, P = 0.007) and positive cultures from bone cores (OR = 1.02, P ≤0.001) and aspirate (OR = 1.02, P ≤0.001). Increased total core length was positively associated with a histopathologic diagnosis of osteomyelitis (OR = 1.81, P = 0.013) and positive cultures from bone cores (OR = 1.65, P = 0.049). Clinical management was affected by ICNB in 37.5% (214 of 570) of cases.

CONCLUSIONS

In this large cohort, ICNB yielded approximately 30% positive cultures and changed clinical management in over one-third of the patients.

Laboratory diagnostics for primary spinal infections in pediatric and adult populations: a narrative review

Primary spinal infection (PSI) is a generic term covering a heterogeneous group of infections that can affect the vertebral body, intervertebral disks, the content of the medullary cavity, and adjacent paraspinal tissues. Patients' characteristics can vary significantly, notably according to their age, and some of these characteristics undoubtedly play a primordial role in the occurrence of a PSI and in the type of offending pathogen. Before approaching the subject of laboratory diagnostics, it is essential to define the characteristics of the patient and their infection, which can then guide the physician toward specific diagnostic approaches. This review critically examined the roles and usefulness of traditional and modern laboratory diagnostics in supporting clinicians' decision-making in cases of pediatric and adult primary spinal infection (PSI). It appears impossible to compare PSIs in children and adults, whether from an epidemiological, clinical, bacteriological, or biological perspective. The recipients are really too different, and the responsible germs are closely correlated to their age. Secondly, the interpretation of traditional laboratory blood tests appears to contribute little guidance for clinicians attempting to diagnose a PSI. Biopsy or needle aspiration for bacterial identification remains a controversial subject, as the success rates of these procedures for identifying causative organisms are relatively uncertain in pediatric populations.Using nucleic acid amplification assays (NAAAs) on biopsy samples has been demonstrated to be more sensitive than conventional cultures for diagnosing PSI. Recent advances in next-generation sequencing (NGS) are particularly interesting for establishing a microbiological diagnosis of a PSI when standard cultures and NAAAs have failed to detect the culprit. We can even imagine that plasma metagenomic NGS using plasma (known as "liquid biopsy") is a diagnostic approach that can detect not only pathogens circulating in the bloodstream but also those causing focal infections, and thus eliminate the need for source sample collection using costly invasive surgical procedures.

Evaluating the Performance of Pathogen-Targeted Positron Emission Tomography Radiotracers in a Rat Model of Vertebral Discitis-Osteomyelitis

BACKGROUND

Vertebral discitis-osteomyelitis (VDO) is a devastating infection of the spine that is challenging to distinguish from noninfectious mimics using computed tomography and magnetic resonance imaging. We and others have developed novel metabolism-targeted positron emission tomography (PET) radiotracers for detecting living Staphylococcus aureus and other bacteria in vivo, but their head-to-head performance in a well-validated VDO animal model has not been reported.

METHODS

We compared the performance of several PET radiotracers in a rat model of VDO. [11C]PABA and [18F]FDS were assessed for their ability to distinguish S aureus, the most common non-tuberculous pathogen VDO, from Escherichia coli.

RESULTS

In the rat S aureus VDO model, [11C]PABA could detect as few as 103 bacteria and exhibited the highest signal-to-background ratio, with a 20-fold increased signal in VDO compared to uninfected tissues. In a proof-of-concept experiment, detection of bacterial infection and discrimination between S aureus and E coli was possible using a combination of [11C]PABA and [18F]FDS.

CONCLUSIONS

Our work reveals that several bacteria-targeted PET radiotracers had sufficient signal to background in a rat model of S aureus VDO to be potentially clinically useful. [11C]PABA was the most promising tracer investigated and warrants further investigation in human VDO.

2022 SPILF - Clinical Practice guidelines for the diagnosis and treatment of disco-vertebral infection in adults

These guidelines are an update of those made in 2007 at the request of the French Society of Infectious Diseases (SPILF, Société de Pathologie Infectieuse de Langue Française). They are intended for use by all healthcare professionals caring for patients with disco-vertebral infection (DVI) on spine, whether native or instrumented. They include evidence and opinion-based recommendations for the diagnosis and management of patients with DVI. ESR, PCT and scintigraphy, antibiotic therapy without microorganism identification (except for emergency situations), therapy longer than 6 weeks if the DVI is not complicated, contraindication for spinal osteosynthesis in a septic context, and prolonged dorsal decubitus are no longer to be done in DVI management. MRI study must include exploration of the entire spine with at least 2 orthogonal planes for the affected level(s). Several disco-vertebral samples must be performed if blood cultures are negative. Short, adapted treatment and directly oral antibiotherapy or early switch from intravenous to oral antibiotherapy are recommended. Consultation of a spine specialist should be requested to evaluate spinal stability. Early lifting of patients is recommended.

Image-Guided Biopsy in Acute Diskitis-Osteomyelitis: A Systematic Review and Meta-Analysis

BACKGROUND. The reported sensitivity and yield of image-guided biopsies for diskitis-osteomyelitis vary widely. OBJECTIVE. The purpose of this study was to perform a systematic review of the literature and meta-analysis of pooled sensitivity data to elucidate strategies for optimal image-guided biopsies among patients suspected to have diskitis-osteomyelitis. EVIDENCE ACQUISITION. A comprehensive literature search was performed for studies of patient populations with proven or suspected diskitis-osteomyelitis that included percutaneous image-guided biopsy as part of the workup algorithm. Type of pathogens, imaging modality used for biopsy guidance, tissue targeted, antibiotic administration at the time of biopsy, true microbiology positives, true microbiology negatives, false microbiology positives, false microbiology negatives, disease (i.e., diskitis-osteomyelitis) positives as determined by reference standard, true infection positives (i.e., positive microbiology or pathology results), and total number of biopsies performed were extracted from the studies. Microbiology sensitivity, microbiology biopsy yield, and infection sensitivity were calculated from the pooled data. These terms and the data required to calculate them were also defined in detail. EVIDENCE SYNTHESIS. Thirty-six articles satisfied inclusion criteria and were used for analysis. The pooled microbiology sensitivity, infection sensitivity, and microbiology biopsy yields were 46.6%, 70.0%, and 26.7%, respectively. Mycobacterium tuberculosis-only microbiology sensitivity was significantly higher than both pyogenic bacteria and mixed-organism microbiology sensitivity (p < .001). Staphylococcus aureus was the most common causative organism (28.6%). Pooled microbiology sensitivity was not significantly different for CT guidance and fluoroscopy guidance (p = .16). There was a statistically significant difference between pooled microbiology sensitivity of bone/end plate (45.5%) and disk/paravertebral soft-tissue (64.8%) image-guided biopsies (p < .001). There was no statistically significant difference in pooled microbiology sensitivities for patients who received antibiotics before the procedure (46.2%) and those who did not (44.6%) (p = .70). CONCLUSION. Image guidance by CT or fluoroscopy does not affect microbiology yield, disk and paravertebral soft-tissue biopsies should be considered over bone and end plate biopsies, and preprocedural antibiotic administration does not appear to impact biopsy results. CLINICAL IMPACT. Understanding and correctly applying reported statistics contribute to appropriate interpretation of the abundant literature on this topic and optimization of care for patients with diskitis-osteomyelitis.

Site matters: Image-guided percutaneous sampling of intervertebral disc results in increased positive diagnostic yield in spondylodiscitis

Spondylodiscitis is a common referral to spinal on call services. Identification of the causative organism is vital in order to dictate the appropriate antibiotic treatment. In this context, the surgical and interventional radiology team is often asked to perform a diagnostic biopsy. The aim of the present study was to assess whether the sampling location affects the diagnostic yield. Our results suggest that the overall positive diagnostic yield was 35%. When disc material was included in the sample the diagnostic yield significantly improved to 47%. Bone sampling alone had a positive yield of 15%. Age, pre-biopsy CRP, pre-biopsy use of antibiotics did not seem to affect the likelihood of obtaining a positive yield. These results suggests that when performing image guided biopsies for suspected cases of spondylodiscitis the inclusion of disc material is important.

Lumbar Spondylodiscitis Mimicking Cholecystitis: A Case Report and Review of Literature

BACKGROUND

 Lower back pain is a frequent cause of emergency department visits and one of the leading causes of the disease burden worldwide. The purpose of this case report and literature review was to discuss atypical abdominal entities mimicking spinal diseases typically presenting with lower back pain.

METHODS

 A 79-year-old man presented with lower back pain and urinary incontinence after receiving a non-image-guided lumbar infiltration treatment 4 weeks prior to admission. The magnetic resonance imaging (MRI) highlighted multisegmental hyperintensities in the intervertebral disk spaces of the lumbar spine indicative for spondylodiscitis. Antibiotic treatment over a week did not lead to significant clinical improvement. Blood cultures, cardiologic, otorhinolaryngologic, and dental examinations turned out negative for a focus of infection. A computed tomography (CT) guided biopsy was indicated after discontinuation of antibiotic treatment for less than 24 hours. Rapid clinical deterioration with concomitant onset of abdominal pain resulted in the diagnosis of cholecystitis, which required cholecystectomy. We performed a systematic literature review using the Pubmed database for the keywords "spondylodiscitis," "spine," "abdominal," and "cholecystitis," to identify abdominal diseases that mimic spine pathologies and spinal diseases that mimic abdominal pathologies.

RESULTS

 No other report in English literature of cholecystitis associated with initial onset of lower back pain was identified. Eighteen reports referred to abdominal conditions that mimic spinal diseases, among them a patient with cyclic lumbar back pain who received a lumbar spinal fusion who, after persisting symptoms led to further diagnostic procedures, was ultimately diagnosed with endometriosis. Spinal symptoms included paraplegia and urinary incontinence as results of acute aortic pathologies. Eleven reports presented spinal pain mimicking abdominal conditions including abdominal pain and diarrhea as well as have had surgical procedures such as an appendectomy before the spinal condition was discovered.

CONCLUSION

 Clinical symptoms of the spine such as lower back pain can be unspecific and lead to false conclusions in the presence of concomitant pathologies in MRI. Only clinical deterioration in our case patient prompted correction of the diagnosis on day 7. Initial workup for alternative common infectious foci such as lung and urinary tract was performed, but further abdominal workup despite the absence of abdominal symptoms may have led to an earlier diagnosis. Our literature review found several cases of misdiagnosed spinal and abdominal conditions. Some had undergone unnecessary surgical procedures before the right diagnosis was made. Because of the high incidence of symptoms such as lumbar back pain and abdominal pain, considering optimal patient care as well as economic aspects, it would be essential to conduct an interdisciplinary clinical management to avoid errors in the early stage of diagnostics.

Diagnostic Yield of Computed Tomography-Guided Procedures for Spondylodiscitis

PURPOSE

To identify the diagnostic yield and predictive factors for microbiological diagnosis in patients with spondylodiscitis through computed tomography (CT)-guided biopsy or aspiration.

MATERIALS AND METHODS

A retrospective review of 102 patients with suspected spondylodiscitis who underwent CT-guided procedures in an 8-year period was conducted. Analyzed variables were demographic data, C-reactive protein, pre-biopsy MRI findings, prior antibiotic use, site of biopsy/aspiration, histopathological findings, culture results and radiation dose.

RESULTS

The culture yield among all sites was 56%, 85.6% for paravertebral/discal fluid aspiration, 66.7% for disk-only biopsy, 52.9% for paravertebral soft tissue biopsy, and 39.6% for endplate bone-disk unit. Patients with paravertebral/disk collection on MRI had better yields when submitted to fluid aspiration instead of biopsy of other sites (78.9% vs. 36.6%; p = 0,006). Pyogenic etiology corresponded to 68.3% of cases and Staphylococcus aureus was the most common agent. Prior antibiotics exposure was associated with a lower yield (66.2% vs. 40.9%, p = 0,016).

CONCLUSIONS

CT-guided procedures are safe and well-tolerated in patients with suspected spondylodiscitis, with good microbiologic yield particularly in the presence of paravertebral/discal abscess.

Culture Yield in the Diagnosis of Native Vertebral Osteomyelitis: A Single Tertiary Center Retrospective Case Series with Literature Review

Background

Vertebral osteomyelitis is a serious condition that requires prompt diagnosis to avoid delays in proper management. There is no well-defined gold standard for diagnosis. We describe the current diagnostic approach at our institution, with a focus on the yield of image-guided vertebral biopsy.

Methods

We performed a single-centre 10-year retrospective case series, including adults with imaging suggestive of vertebral osteomyelitis/discitis, with either positive blood cultures, and/or a vertebral biopsy. We defined positive histopathology as our gold standard for test characteristic evaluation of biopsy cultures.

Results

Out of 694 patients identified, 221 met our inclusion criteria, and 173/221 (78.2%) patients underwent a spinal biopsy. Of those patients with biopsies, 113 (65%) had received antibiotics within 2 weeks preceding their evaluation. Six of 43 (13.9%) bone specimens were positive by culture, while 66/152 (43.4%) of disc specimens were culture positive. Forty-seven of 84 (55.9%) histopathology (bone or disc) specimens were diagnostic for osteomyelitis/discitis. The sensitivity of bone and disk culture were 30.0% and 56.0%, respectively, with specificities of 92.8% and 75.0%, respectively. Twenty-three (13.4%) patients had repeat biopsies, including 10 bone specimens and 14 disc specimens, and 11 (47.8%) specimens had histopathology performed which diagnosed an additional 3/23 patients (13% additional diagnostic yield).

Conclusions

Culture of percutaneous biopsy of disc resulted in the highest diagnostic yield. Histopathology added to the diagnostic yield in culture-negative specimens. Histopathologic evaluation of bone had better yield than bone culture. A repeat biopsy can add to the diagnostic yield.

Non-specific spondylodiscitis: a new perspective for surgical treatment

PURPOSE

Pyogenic spondylodiscitis is a relatively rare spinal disease; non-specific spondylodiscitis (NSS) cases are increasing. This study aims to identify if changes of inflammatory markers under antibiotic therapy can be used to determine which NSS patients can benefit from surgical indication earlier than others.

METHODS

Two groups of patients with NSS were examined. Group A underwent surgery, while Group B was treated conservatively. Group B was also subdivided in patients undergoing antibiotic therapy for > 6 weeks (B1) and < 6 weeks (B2). Groups were compared for age, gender, BMI, blood levels of ESR and CRP and VAS scale.

RESULTS

There were no differences (P = 0.06) in reduction in ESR at 4 weeks between two main groups. A reduction in CRP, with < 2.7 mg/dl at 4 weeks, was observed in Group A (P = 0.01). Comparing Group B1 to B2, a reduction (P = 0.0001) in VAS, ESR and CRP at 4 weeks was observed in Group B2. It was possible to isolate the pathogen in 52.8% of Group B, without any differences on VAS, ESR and CRP values and on length of the antibiotic therapy.

CONCLUSIONS

The surgical treatment should be considered for patients who, after 4 weeks of conservative therapy, do not show a reduction in the ESR < 50 mm/h and of the CRP < 2.7 g/dl. The comparison between groups underwent surgically and those treated conservatively showed a reduction in the CRP at 4 weeks and better VAS for pain at 3 months in Group A.

Spinal endoscopy: evidence, techniques, global trends, and future projections

The utilization of indirect visualization during procedures has been increasingly replacing traditional forms of direct visualization across many different surgical specialties. The adoption of arthroscopy, using small cameras placed inside joints, has transformed musculoskeletal care over the last several decades, allowing surgeons to provide the same anatomic solutions with less tissue dissection, resulting in lower requirements for inpatient care, reduced costs, and expedited recovery.  For a variety of reasons, spine surgery has lagged behind other specialties in the adoption of indirect visualization.  Nonetheless, patient demand for less invasive spine procedures and surgeon drive to provide these solutions and improve care quality has driven global adoption of spinal endoscopy.  There are numerous endoscopic platforms and techniques currently utilized, and these systems are rapidly evolving.  Additionally, the variance in technology and health system incentives across the globe has generated tremendous regional heterogeneity in the utilization of spinal endoscopic procedures.  We present a consolidated review, including the background, evidence, techniques, and trends in spinal endoscopy, so that clinicians can gain a deeper understanding of this rapidly evolving domain of spinal healthcare.

Diagnostic yield of image-guided biopsy in patients with suspected infectious spondylodiscitis : a prospective study from a tuberculosis-endemic country

AIMS

The aims of this study were to determine the diagnostic yield of image-guided biopsy in providing a final diagnosis in patients with suspected infectious spondylodiscitis, to report the diagnostic accuracy of various microbiological tests and histological examinations in these patients, and to report the epidemiology of infectious spondylodiscitis from a country where tuberculosis (TB) is endemic, including the incidence of drug-resistant TB.

METHODS

A total of 284 patients with clinically and radiologically suspected infectious spondylodiscitis were prospectively recruited into the study. Image-guided biopsy of the vertebral lesion was performed and specimens were sent for various microbiological tests and histological examinations. The final diagnosis was determined using a composite reference standard based on clinical, radiological, serological, microbiological, and histological findings. The overall diagnostic yield of the biopsy, and that for each test, was calculated in light of the final diagnosis.

RESULTS

The final diagnosis was tuberculous spondylodiscitis in 250 patients (88%) and pyogenic spondylodiscitis in 22 (7.8%). Six (2.1%) had a noninfectious condition-mimicking infectious spondylodiscitis, and six (2.1%) had no definite diagnosis and improved without specific treatment. The diagnosis was made by image-guided biopsy in 152 patients (56%) with infectious spondylodiscitis. Biopsy was contributory in identifying 132/250 patients (53%) with tuberculous spondylodiscitis, and 20/22 patients (91%) with pyogenic spondylodiscitis. Histological examination was the most sensitive diagnostic modality, followed by Xpert MTB/RIF assay.

CONCLUSION

Image-guided biopsy has a reasonably high diagnostic yield in patients with suspected infectious spondylodiscitis. A combination of histological examination, Xpert MTB/RIF assay, bacterial culture, and sensitivity provides high diagnostic accuracy in a country in which TB is endemic. Cite this article: Bone Joint J 2022;104-B(1):120-126.

Presumptive bacteriological diagnosis of spondylodiscitis in infants less than 4 years by detecting K. kingae DNA in their oropharynx: Data from a preliminar two centers study

Background and Objectives

Most cases of spondylodiscitis in children aged between 6 and 48 months old could be caused primarily by K. kingae. The present prospective study aimed to determine whether an innovative and indirect diagnosis approach - based on detection of K. kingae DNA in the oropharynx of children with suspected spondylodiscitis - provides sufficient evidence that this microorganism is responsible for the infection.

Methods

We prospectively analysed infants admitted for spondylodiscitis, considering above all the results of PCR realized in oropharyngeal swabs and in blood samples.

Results

Four of the 29 performed K. kingae-specific real-time PCR assay in blood were positive (13.8%), whereas 28 of the 32 K. kingae-specific real-time PCR assay realized on throat swabs were positive (87.5%).

Conclusions

This study demonstrates that performing oropharyngeal swab PCR is able to detect K. kingae in almost 90% of the toddlers with confirmed spondylodiscitis. That provides strong arguments for the hypothesis that K. kingae should be considered as the main aetiological pathogen to suspect in children between 6 and 48 months old with spondylodiscitis. Finally, it seems to us reasonable that oropharyngeal swab may become an early decision-making tool for the indirect identification of K. kingae in spondylodiscitis.

The potential of metagenomic next-generation sequencing in diagnosis of spinal infection: a retrospective study

PURPOSE

Metagenomic next-generation sequencing (mNGS) is a new approach to identify the infecting organism in infectious diseases. Our aim was to evaluate the accuracy of mNGS in determining the etiology of spinal infection.

METHODS

In this retrospective study, patients who had a suspected spinal infection and underwent mNGS for diagnosis in our hospital were eligible for inclusion. Samples for mNGS, culture, and histopathological tests were collected surgically or with a CT-guided needle biopsy. Sensitivity and specificity were calculated for mNGS and culture test, using histopathological results as reference.

RESULTS

A total of 31 mNGS tests in 30 cases were included. Twenty-six cases were classified as infected, and four cases were considered aseptic. mNGS achieved a specificity of 75.0% [95% confidence interval (CI), 21.9% to 98.7%], sensitivity was 70.3% (95% CI, 49.7% to 85.5%). mNGS was more sensitive than culture at 14.8% (95% CI, 4.9% to 34.6%, P < 0.0001). However, the specificities of mNGS and culture were statistically similar.

CONCLUSION

We described here the power of mNGS in the etiological diagnosing of spinal infection. Our study opens the possibility for more extensive use of mNGS techniques in the identification of pathogens in patients with suspected spinal infection.

Clinicoradiographic predictors of percutaneous bone biopsy results among patients with suspected thoracolumbar spine infection

BACKGROUND

Image-guided percutaneous thoracolumbar spine biopsy is frequently performed in the setting of suspected septic facet arthritis or discitis osteomyelitis (DOM). There are limited data regarding factors associated with a positive biopsy result among these patients.

MATERIALS AND METHODS

Patients with suspected DOM who underwent spine biopsy were identified. Samples yielding a positive culture and/or histopathology suggestive of acute osteomyelitis were considered positive. The associations between selected medical comorbidities, laboratory values, pre-biopsy antibiotic administration, imaging findings and biopsy results were investigated.

RESULTS

121 patients underwent percutaneous biopsy with 35.5% yielding positive results. Biopsy results showed no correlation with comorbidities. The only laboratory value that correlated with a positive biopsy yield was blood culture positivity (p = 0.03). The imaging findings that correlated with a positive biopsy yield were the presence of a paraspinal fluid collection or epidural abscess (p = 0.003 and 0.018, respectively). Sampling paraspinal fluid collections, when present, resulted in a higher rate of a positive biopsy yield compared to sampling of bone or disc (p = 0.006). Patients who received antibiotics had a higher rate of a positive biopsy yield (p = 0.014). In those with positive blood cultures, biopsy yielded the same antimicrobial susceptibility profile in 13/14 cases.

CONCLUSION

The presence of a paraspinal fluid collection or epidural abscess is correlated with positive biopsy yield, and paraspinal fluid collections should be targeted for biopsy. Other imaging findings did not correlate with biopsy yield. Biopsy may not offer additional information for patients with positive blood cultures.

Optimal microbiological sampling for the diagnosis of osteoarticular infection

Infection is a dire complication afflicting every field of orthopaedics and traumatology. If specific clinical, laboratory and imaging parameters are present, infection is often assumed even in the absence of microbiological confirmation. However, apart from confirming infection, knowing the exact infecting pathogen(s) and their antimicrobial susceptibility patterns is paramount to help guide treatment. Every effort should therefore be undertaken with that goal in mind.Not all microbiological findings carry the same relevance, and knowing exactly how and where a sample was collected is key. Several different sampling techniques are available, and one must be aware of both advantages and limitations. Microbiological sampling alternatives in some of the most common clinical scenarios such as native and prosthetic joint infections, osteomyelitis and fracture-related infections, spinal and diabetic foot infections will be discussed.Orthopaedic surgeons should also be aware of basic laboratory sample processing techniques as they have a direct impact on the way specimens should be dealt with and transported to the laboratory. Only by knowing these basic principles will surgeons be able to participate in the multidisciplinary discussion and decision making around how to interpret microbiological findings in each specific patient. Cite this article: EFORT Open Rev 2021;6:390-398. DOI: 10.1302/2058-5241.6.210011.

Review article: the current status of CT-guided needle biopsy of the spine

CT-guided percutaneous needle biopsy of the spine is a well-described technique for determining the nature of indeterminate vertebral lesions or establishing a diagnosis of spinal infection, the high diagnostic accuracy and the safety of the procedure having been extensively documented. The purpose of the current article is to review the literature to date on CT-guided spinal biopsy. Specifically, indications for spinal biopsy, techniques for optimising yield, detail of the approaches for various spinal levels which is dependent upon both the region within the spinal column and lesion location within the vertebra (body vs. neural arch), determinants of biopsy outcome and complications are covered. It is hoped that the review will be of particular benefit to junior radiologists who are required to perform this procedure.

Early surgical debridement and fixation for pyogenic lumbar spondylodiscitis

Background

Management of pyogenic lumbar spondylodiscitis still represent a major conflict and challenge in neurosurgery due to different pathogens and the different methods available for management.

Objective

The aim of this study was to evaluate the outcome of posterior lumbar spinal fixation with debridement as a treatment modality in the management of pyogenic lumbar spondylodiscitis.

Patients and method

This is a prospective study conducted on patients presenting to the Neurosurgery Department of Cairo University hospitals diagnosed to have either spontaneous or iatrogenic pyogenic lumbar spondylodiscitis. All cases were operated upon by surgical debridement, drainage, and posterior lumbar fixation in the same setting. Antibiotics were prescribed according to the obtained culture and sensitivity. Laboratory follow-up was done to all patients. Clinical outcome was evaluated in terms of the Denis Functional Pain Scale. Follow-up period ranged from 5 to 14 months.

Results

A total of 25 patients comprised of 15 males and 9 females with a mean age of 45.7 years (range 32–63 years) were included in this study. Nine cases had a previous lumbar discectomy surgery, and 15 cases presented with spontaneous spondylodiscitis. L4–5 level was the most frequent site of pyogenic discitis. Excellent outcome and good outcomes (score 1–3 in Denis Functional Pain Scale) were reported in 84% of the patients and poor outcomes (score 4–5) in 16%.

Conclusion

Surgical fixation and debridement can be considered as an effective modality in the management of pyogenic lumbar spondylodiscitis with early ambulation, good control of pain, and early hospital discharge.

Defining Disc Biopsy Timing in Relation to Blood Culture Results for Inpatients with Suspected Discitis-Osteomyelitis

PURPOSE

To determine optimal timing of biopsy for suspected discitis-osteomyelitis (DOM) with respect to preliminary blood culture results and the effect of biopsy timing on hospital length of stay (LOS).

MATERIALS AND METHODS

This retrospective study reviewed disc/vertebral biopsies for suspected DOM performed between 2010 and 2018. A total of 107 disc/vertebral biopsies were performed on 96 inpatients (mean ± SD age 57.9 ± 14.5 years, 68 men/28 women) for suspected DOM, and 100 cases of DOM were clinically confirmed and treated. Descriptive and regression statistics were performed with LOS as the primary outcome.

RESULTS

Of disc biopsies in clinically confirmed cases, 68% were positive; 20% of all biopsies had preliminary positive blood cultures after 2 hospital days. There was no difference in LOS between cases with biopsy performed ≤ 2 days after blood culture and cases with biopsy performed > 2 days after blood culture (P = .40). Regression analysis showed no association between positive biopsy results and sepsis, white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), or C-reactive protein (CRP). Biopsy yield was not significantly decreased in patients previously taking antibiotics (P = .09).

CONCLUSIONS

Waiting 2 days for preliminary blood culture results could avoid disc/vertebral biopsy in 20% of patients and does not significantly impact hospital LOS. Additionally, clinical factors (sepsis, WBC count, CRP, and ESR) do not have predictive value for positive disc biopsy results.

The impact of antibiotic pre-treatment on diagnostic yield of CT-guided biopsy for spondylodiscitis: A multi-centre retrospective study and meta-analysis

INTRODUCTION

Patients with suspected spondylodiscitis often undergo CT-guided biopsy to identify a causative microbiological organism. Antibiotic pre-treatment has been postulated as a cause for a negative biopsy, although previous clinical studies have been heterogenous with a meta-analysis suggesting no effect. The aim of this study was to assess the impact of antibiotic pre-treatment on microbiological yield.

METHODS

Retrospective review of consecutive adult patients undergoing CT-guided biopsy for suspected spondylodiscitis in two tertiary centres between 2010 and 2016. Demographic, procedural and clinical data were collected. Antibiotic pre-treatment was ascertained from patient drug charts.

RESULTS

Over the 6-year period, 104 biopsies in 104 patients were included. 51% had a positive microbiological yield at CT-guided biopsy, with the most common isolated organism being Staphylococcus aureus (10.6%). Over two thirds of patients (69.3%) were off antibiotics at time of biopsy. There was no significant difference in microbiological yield in those patients on versus off antibiotics (48.2% vs 54.2%, P = 0.55). 10.6% patients had a final diagnosis of Mycobacterium tuberculosis spondylodiscitis, and this organism was significantly associated with a positive microbiological yield (90.9% vs 46.2%, P = 0.01). There was an inverse association between the presence of fever and sepsis with positive microbiological yield.

CONCLUSIONS

CT-guided biopsy in suspected spondylodiscitis obtains a positive microbiological yield in about half of patients. This was significantly higher in patients diagnosed with tuberculosis spondylodiscitis, but there was no significant difference with antibiotic pre-treatment. Therefore, antibiotic pre-treatment should not preclude clinicians from pursuing a microbiological sample through CT-guided biopsy.

Listeria spondylodiscitis: an uncommon etiology of a common condition; a case report

Background

Listeriosis is a severe food-borne infection caused by the Gram-positive rod, Listeria monocytogenes. Despite the low incidence (3–8 cases per million), Listeriosis has a case fatality rate of 20–30% as it occurs predominantly in immunocompromised individuals at extremes of age, diabetics and pregnant women. Listeriosis classically presents as a febrile gastroenteritis, isolated bacteremia, meningitis, or maternal-fetal infections. Focal bone and joint infection are rare and primarily involve orthopedic implant devices. Here, we present the first case of Listeria-associated spondylodiscitis.

Case presentation

A 79-year-old male presents with acute-on-chronic back pain in the absence of risk factors or exposures, aside from age. On radiological imaging, spondylodiscitis of L3-L4 was diagnosed. Subsequently, a CT-guided biopsy was performed to aid in confirming microbiological aetiology. Listeria monocytogenes was grown in culture and patient received appropriate antibacterial therapy.

Conclusion

The case highlights the utility of image-guided tissue sampling in aiding diagnosis and management in patients with vertebral osteomyelitis. It also encourages consideration of uncommon organisms such as Listeria as an etiology of vertebral osteomyelitis, even in the absence of prosthetic implants.

Predictive factors for positive disco-vertebral biopsy culture in pyogenic vertebral osteomyelitis, and impact of fluoroscopic versus scanographic guidance

Background

The aims of this study were to identify the predictive factors for microbiological diagnosis through disco-vertebral biopsy (DVB) in patients with pyogenic vertebral osteomyelitis (PVO) and negative blood cultures, and compare the performance of DVB under fluoroscopic versus scanographic guidance.

Methods

We performed a cohort study comparing positive and negative DVB among patients with PVO. All cases of PVO undergoing a DVB for microbiological diagnosis in our center were retrospectively reviewed. Infections due to Mycobacterium tuberculosis, infections on foreign device, and non-septic diseases were excluded. Anamnestic, clinical, biological, microbiological, as well as radiological data were collected from medical charts thanks to a standardized data set.

Results

A total of 111 patients were screened; 88 patients were included. Microbiological cultures were positive in 53/88 (60.2%) patients. A thickening of the paravertebral tissue ≥10 mm on magnetic resonance imaging (MRI) in axial MR scans was a predictive factor of DVB microbiological positivity (52.4% vs. 13.3%; p = 0.006; OR = 5.4). Overall, 51 DVB were performed under fluoroscopic guidance and 37 under scanographic guidance. Considering lumbar DVB, 25/36 (69.4%) of cases yielded positive results under fluoroscopic guidance versus 5/15 (33.3%) under scanographic guidance (p = 0.02; OR = 4.4). No adverse event linked to DVB was notified.

Conclusion

Every patient with PVO and negative blood cultures should undergo a DVB. A thickening of the paravertebral tissue ≥10 mm on MRI is associated with a higher rate of positive DVB culture. A lumbar DVB under fluoroscopic guidance is more sensitive than under scanographic guidance to identify the micro-organism involved.

[Pyogenic spondylodiscitis: symptoms, diagnostics and therapeutic strategies]

BACKGROUND

Pyogenic spondylodiscitis is a rare disease that is being diagnosed with increasing frequency in recent years. It is associated with a high morbidity and mortality.

DIAGNOSIS

Often, because of its nonspecific symptoms, pyogenic spondylodiscitis is diagnose with some delay. In addition to pathogen detection, MRI is the gold standard to diagnose pyogenic spondylodiscitis. Also, x-ray imaging and CT can be carried out for surgical planning and for subsequent follow-up imaging. If blood or tissue cultures are negative, open surgical biopsies should be preferred over CT-guided biopsies.

THERAPY

The therapy can be conservative, such as immobilization, as well as antibiotics and analgesics, or surgical. If, for example, neurological deficits, spinale instabilities or deformities, septic disease progression or extensive abscess formations are present, surgical therapy is indicated. The surgical treatment strategies depend on the severity of the disease.

OUTLOOK

The prognosis is dependent on a rapid diagnosis and a swift start to therapy. There is no clear evidence with regard to treatment options (conservative vs. surgical therapy).

The clinical utility of fluoroscopic versus CT guided percutaneous transpedicular core needle biopsy for spinal infections and tumours: a randomized trial

BACKGROUND CONTEXT

Biopsy is important to obtain microbiological and histopathological diagnosis in spine infections and tumors. To date, there have been no prospective randomized trials comparing fluoroscopic guided and computed tomography (CT) transpedicular biopsy techniques. The goal of this study was to evaluate the accuracy, safety, and diagnostic outcome of these two diagnostic techniques.

PURPOSE

To evaluate the accuracy, safety, and diagnostic outcome of fluoroscopic guided and CT transpedicular biopsy techniques.

STUDY DESIGN

Prospective randomized trial.

PATIENT SAMPLE

Sixty consecutive patients with clinical symptoms and radiological features suggestive of spinal infection or malignancy were recruited and randomized into fluoroscopic or CT guided spinal biopsy groups. Both groups were similar in terms of patient demographics, distribution of spinal infections and malignancy cases, and the level of biopsies.

OUTCOME MEASURES

The primary outcome measure was diagnostic accuracy of both methods, determined based on true positive, true negative, false positive, and false negative biopsy findings. Secondary outcome measures included radiation exposure to patients and doctors, complications, and postbiopsy pain score.

METHODS

A transpedicular approach was performed with an 8G core biopsy needle. Specimens were sent for histopathological and microbiological examinations. Diagnosis was made based on biopsy results, clinical criteria and monitoring of disease progression during a 6-month follow up duration. Clinical criteria included presence of risk factors, level of inflammatory markers and magnetic resonance imaging findings. Radiation exposure to patients and doctors was measured with dosimeters.

RESULTS

There was no significant difference between the diagnostic accuracy of fluoroscopic and CT guided spinal biopsy (p=0.67) or between the diagnostic accuracy of spinal infection and spinal tumor in both groups (p=0.402 for fluoroscopy group and p=0.223 for CT group). Radiation exposure to patients was approximately 26 times higher in the CT group. Radiation exposure to doctors in the CT group was approximately 2 times higher compared to the fluoroscopic group if a lead shield was not used. Lead shields significantly reduced radiation exposure to doctors anywhere from 2 to 8 times. No complications were observed for either group and the differences in postbiopsy pain scores were not significant.

CONCLUSIONS

The accuracy, procedure time, complication rate and pain score for both groups were similar. However, radiation exposure to patients and doctors were significantly higher in the CT group without lead protection. With lead protection, radiation to doctors reduced significantly.

Combination of Imaging Features and Clinical Biomarkers Predicts Positive Pathology and Microbiology Findings Suggestive of Spondylodiscitis in Patients Undergoing Image-Guided Percutaneous Biopsy

BACKGROUND AND PURPOSE

Pathology and microbiology results for suspected spondylodiscitis on MR imaging are often negative in up to 70% of cases. We aimed to predict whether MR imaging features will add diagnostic value when combined with clinical biomarkers to predict positive findings of spondylodiscitis on pathology and/or microbiology from percutaneous biopsy.

MATERIALS AND METHODS

In this retrospective single-center institutional review board-approved study, patients with radiologically suspected spondylodiscitis and having undergone percutaneous biopsies were assessed. Demographic characteristics, laboratory values, and tissue and blood cultures were collected. Pathology and microbiology results were used as end points. Three independent observers provided MR imaging-based scoring for typical MR imaging features for spondylodiscitis. Multivariate logistic regression and receiver operating characteristic analysis were performed to determine an optimal combination of imaging and clinical biomarkers in predicting positive findings on pathology and/or microbiology from percutaneous biopsy suggestive of spondylodiscitis.

RESULTS

Our patient cohort consisted of 72 patients, of whom 33.3% (24/72) had spondylodiscitis. The mean age was 63 ± 16 years with a male/female ratio of 41:31. Logistic regression revealed a combination with an area under the curve of 0.72 for pathology and 0.68 for pathology and/or microbiology. Epidural enhancement on MR imaging improved predictive performance to 0.87 for pathology and 0.78 for pathology and/or microbiology.

CONCLUSIONS

Our findings demonstrate that epidural enhancement on MR imaging added diagnostic value when combined with clinical biomarkers to help predict which patients undergoing percutaneous biopsy will have positive findings for spondylodiscitis on pathology and/or microbiology.

Consensus on the Role of Antibiotic Use in SSI Following Spinal Surgery

In July of 2018, the Second International Consensus Meeting (ICM) on Musculoskeletal Infection convened in Philadelphia, PA was held to discuss issues regarding infection in orthopedic patients and to provide consensus recommendations on these issues to practicing orthopedic surgeons. During this meeting, attending delegates divided into subspecialty groups to discuss topics specifics to their respective fields, which included the spine. At the spine subspecialty group meeting, delegates discussed and voted upon the recommendations for 63 questions regarding the prevention, diagnosis, and treatment of infection in spinal surgery. Of the 63 questions, 17 focused on the use of antibiotics in spine surgery, for which this article provides the recommendations, voting results, and rationales.

CT-guided discitis-osteomyelitis biopsies with negative microbiology: how many days should we wait before repeating the biopsy?

PURPOSE

To determine the number of days to positive CT-guided biopsy sample culture in patients with discitis-osteomyelitis.

METHODS

Our study was IRB approved and HIPAA compliant. All CT-guided biopsies performed for acute discitis-osteomyelitis with positive microbiology between 2002 and 2018 were reviewed. Microbiological organism and days to positive biopsy were documented. Mean, median, skew, and standard deviation were calculated. The proportion of positive cultures that become positive after each day has elapsed was also calculated.

RESULTS

There were 96 true positive cultures, with 64 (67%) male and 32 (33%) female, ages 57 ± 18 (range 19-87) years. Overall, including all culture results, the mean number of days to positive culture was 2.9 ± 3.5 days. The median number of days was 2, with a positive skew of 2.9. At days 1, 2, 3, 4, and 5, 48%, 68%, 78%, 85%, and 89%, respectively, of biopsy samples had a positive microbiology culture.

CONCLUSION

Approximately three-quarters of discitis-osteomyelitis pathogens will be identified by biopsy sample culture by 3 days after CT-guided biopsy. This finding should be considered if planning for a repeat biopsy in the setting of a negative microbiology culture.

Diagnostic Performance of CT-Guided Bone Biopsies in Patients with Suspected Osteomyelitis of the Appendicular and Axial Skeleton with a Focus on Clinical and Technical Factors Associated with Positive Microbiology Culture Results

PURPOSE

To assess diagnostic performance of CT-guided percutaneous needle bone biopsy (CTNBB) in patients with suspected osteomyelitis and analyze whether certain clinical or technical factors were associated with positive microbiology results.

MATERIALS AND METHODS

All CTNBBs performed in a single center for suspected osteomyelitis of the appendicular and axial skeleton during 2003-2018 were retrospectively reviewed. Specific inclusion criteria were clinical and radiologic suspicion of osteomyelitis. Standard of reference was defined using outcome of surgical histopathology and microbiology culture and clinical and imaging follow-up. Technical and clinical data (needle size, comorbidities, clinical factors, laboratory values, blood cultures) were collected. Logistic regression was performed to assess associations between technical and clinical data and microbiology biopsy outcome.

RESULTS

A total of 142 CTNBBs were included (46.5% female patients; age ± SD 46.10 y ± 22.8), 72 (50.7%) from the appendicular skeleton and 70 (49.3%) from the axial skeleton. CTNBB showed a sensitivity of 42.5% (95% confidence interval [CI], 32.0%-53.6%) in isolating the causative pathogen. A higher rate of positive microbiology results was found in patients with intravenous drug use (odds ratio [OR] = 5.15; 95% CI, 1.2-21.0; P = .022) and elevated white blood cell count ≥ 10 × 10⁹/L (OR = 3.9; 95% CI, 1.62-9.53; P = .002). Fever (≥ 38°C) was another clinical factor associated with positive microbiology results (OR = 3.6; 95% CI, 1.3-9.6; P = .011).

CONCLUSIONS

CTNBB had a low sensitivity of 42.5% for isolating the causative pathogen. Rate of positive microbiology samples was significantly higher in patients with IV drug use, elevated white blood cell count, and fever.

Minimally invasive spinal fusion and decompression for thoracolumbar spondylodiscitis

Objective:

The objective was to study the results of the treatment of thoracolumbar spondylodiscitis (SD) through minimally invasive fusion and decompression technique.

Materials and Methods:

All the patients were evaluated clinically and radiologically (X-ray, magnetic resonance imaging, and computed tomography scan) along with necessary laboratory investigations. They underwent the minimally invasive spinal (MIS) decompression and fusion procedure using tubular retractor system and percutaneous transpedicular fixation done under fluoroscopy guidance. They were assessed using pre- and postoperative Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and Kirkaldy-Willis functional outcome criteria. Postoperative radiological assessment of fusion was done. Operating time and fluoroscopy duration were also studied.

Results:

There were a total of 12 patients, with an equal sex ratio of 1:1 with 8 and 4 patients having the involvement of the lumbar and dorsal spine, respectively. The fixation was done in the involved vertebrae in 8 patients and adjacent normal vertebrae in 4 patients. There was an improvement in VAS score from 7.8 to 2.1 and ODI from 64.3 to 16.4. 4 patients had excellent, 7 had good, and 1 had fair outcome in Kirkaldy-Willis functional outcome criteria. There was Grade 2 and 3 fusion in 4 cases each, and 2 patients had Grade 4 fusion. The laboratory studies were found positive for tuberculosis in 3 cases with 7 having necrotizing granulomatous inflammation, and 2 patients had negative results.

Conclusion:

The MIS procedure is a safe and effective method of the management of SD in the thoracolumbar spine.

Management of vertebral osteomyelitis over an eight-year period: The UDIPROVE (UDIne PROtocol on VErtebral osteomyelitis)

OBJECTIVES

Vertebral osteomyelitis (VO) is a compelling clinical entity for clinicians because of its insidious and indolent course, which makes diagnosis difficult.

METHODS

All patients with a suspected diagnosis of VO were analyzed over an 8-year period (January 2009 to January 2017). The UDIPROVE protocol (UDIne PROtocol on VErtebral osteomyelitis) was applied in all cases. The primary endpoint was the performance of the UDIPROVE protocol to obtain the causal bacteria of infection.

RESULTS

During the study period, 133 episodes of confirmed VO were observed. The etiology of infection was obtained in 73.6% of cases: 70.5% were gram-positive, 16.3% were gram-negative, and 13.2% were mycobacteria. ¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) showed that for tubercular VO, the median standard uptake value (SUV) was higher when compared with VO caused by other bacteria. Clinical cure at the end of therapy was reported in 85.7% of patients. Previous antimicrobial therapy and a delay of more than 5 days in performing biopsy were associated with an undiagnosed etiology of VO. Targeted antibacterial therapy and follow-up with FDG-PET/CT were associated with clinical cure at the end of therapy, while the involvement of more than two vertebrae and inadequate drainage were associated with failure.

CONCLUSIONS

Rigorous application of the UDIPROVE protocol allowed the causative pathogens of VO to be obtained - at about twice the rate reported in the literature. The use of FDG-PET/CT for the follow-up of infection was more reliable when compared to magnetic resonance imaging (MRI).

Joint EANM/ESNR and ESCMID-endorsed consensus document for the diagnosis of spine infection (spondylodiscitis) in adults

PURPOSE

Diagnosis of spondylodiscitis (SD) may be challenging due to the nonspecific clinical and laboratory findings and the need to perform various diagnostic tests including serologic, imaging, and microbiological examinations. Homogeneous management of SD diagnosis through international, multidisciplinary guidance would improve the sensitivity of diagnosis and lead to better patient outcome.

METHODS

An expert specialist team, comprising nuclear medicine physicians appointed by the European Association of Nuclear Medicine (EANM), neuroradiologists appointed by the European Society of Neuroradiology (ESNR), and infectious diseases specialists appointed by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), reviewed the literature from January 2006 to December 2015 and proposed 20 consensus statements in answer to clinical questions regarding SD diagnosis. The statements were graded by level of evidence level according to the 2011 Oxford Centre for Evidence-based Medicine criteria and included in this consensus document for the diagnosis of SD in adults. The consensus statements are the result of literature review according to PICO (P:population/patients, I:intervention/indicator, C:comparator/control, O:outcome) criteria. Evidence-based recommendations on the management of adult patients with SD, with particular attention to radiologic and nuclear medicine diagnosis, were proposed after a systematic review of the literature in the areas of nuclear medicine, radiology, infectious diseases, and microbiology.

RESULTS

A diagnostic flow chart was developed based on the 20 consensus statements, scored by level of evidence according to the Oxford Centre for Evidence-based Medicine criteria.

CONCLUSIONS

This consensus document was developed with a final diagnostic flow chart for SD diagnosis as an aid for professionals in many fields, especially nuclear medicine physicians, radiologists, and orthopaedic and infectious diseases specialists.

Minimally invasive spine surgery in the treatment of pyogenic spondylodiscitis: an initial retrospective series study

Introduction

Pyogenic spondylodiscitis is a bacterial infection affecting the intervertebral disc and its adjacent vertebrae. Although relatively rare, it is a challenging medical disease with a poor prognosis that requires immediate diagnosis and treatment with suitable antibiotics.

Aim

To evaluate the clinical outcome of minimally invasive spine surgery (MIS) for pyogenic spondylodiscitis.

Material and methods

The retrospective study cohort consisted of 10 consecutive patients who had undergone MIS decompression and/or discectomy for thoracic or lumbar pyogenic spondylodiscitis in our hospital. Data including patient characteristics, symptoms, visual analog scale (VAS) score, surgical approach and postoperative outcomes were obtained for retrospective analysis.

Results

Between January 2005 and December 2013, 10 patients underwent MIS decompression in the Department of Orthopedics in our medical university. Seven of these patients had lumbar infections and 3 had thoracic infections. All 10 patients had improved VAS scores immediately after surgery and after discharge. The VAS score (respectively on postoperative day 1 and day 7) suggested that the patients in this study had significantly less pain than preoperatively (day 1: 5 vs. 9, p < 0.001; day 7: 2.9 vs. 9, p < 0.001). The organism was obtained in 10 (100%) patients by the operative cultures. All patients achieved an excellent clinical recovery without the need for further spine surgery. All patients underwent postoperative imaging during follow-up and showed complete resolution or dramatically improved magnetic resonance imaging changes.

Conclusions

Minimally invasive spine surgery is a safe and effective surgical approach for pyogenic spondylodiscitis.

Computed-tomography-guided biopsy in suspected spondylodiscitis: Single-center experience including 201 biopsy procedures

Our propose is to evaluate CT-guided biopsies in suspected spondylodiscitis with respect to puncture site, microbiology findings, histopathology findings and impact on antibiotic therapy. 86 CT-guided spine interventions in suspected spondylodiscitis comprising 201 biopsy procedures were analyzed. Medical records of all patients were screened for microbiology and histopathology reports as well as date, duration and kind of antibiotic therapy. Statistical analyses included calculation of Chi²-tests and logistic regression analyses. Locations of biopsies were intervertebral disc (48.3%), paravertebral soft-tissue (38.3%) and vertebral body (10.9%). Positive microbiological findings were found altogether in 33.8% of cases, positive histopathological findings in 53.6%. Significant associations between positive microbiological findings, positive histopathological findings and antibiotic therapy, respectively, were found. Location of biopsies did not significantly influence rate of positive findings. From the variables age, white blood cell count, serum creatinine and puncture site, none were found to be an independent predictor for a positive microbiological result. We concluded that CT-guided biopsy of intervertebral disc and paravertebral soft tissue yields positive microbiologic findings in a significant proportion of cases. Puncture site is not associated with positive results of microbiology or histopathology.

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.

Bone and Soft-Tissue Biopsies: What You Need to Know

Percutaneous, image-guided musculoskeletal biopsy, due to its minimal invasive nature, when compared with open surgical biopsy, is a safe and effective technique which is widely used in many institutions as the primary method to acquire tissue and bone samples. Indications include histopathologic and molecular assessment of a musculoskeletal lesion, exclusion of malignancy in a bone/vertebral fracture, examination of bone marrow, and infection investigation. Preprocedural workup should include both imaging (for lesion assessment and staging) and laboratory (including coagulation tests and platelet count) studies. In selected cases, antibiotic prophylaxis should be administered before the biopsy. Core needle biopsy of musculoskeletal lesions has a diagnostic accuracy that ranges from 66 to 98% with higher diagnostic yield for lytic, large-size, malignant lesions and when multiple and long specimens are obtained. Reported complication rates range between 0 and 10% and usually do not exceed 5%, with a suggested threshold of 2%. The purpose of this review article is to illustrate the technical aspects, the indications, and the methodology of percutaneous image-guided bone biopsy that will assist the interventional radiologist to perform these minimal invasive techniques.

Spinal infections in children: a multicentre retrospective study

Aims

This multicentre, retrospective study aimed to improve our knowledge of primary pyogenic spinal infections in children by analyzing a large consecutive case series.

Patients and Methods

The medical records of children with such an infection, treated at four tertiary institutions between 2004 and 2014, were analyzed retrospectively. Epidemiological, clinical, paraclinical, radiological, and microbiological data were evaluated. There were 103 children, of whom 79 (76.7%) were aged between six months and four years.

Results

We confirmed a significant male predominance in the incidence of primary pyogenic spinal infections in children (65%). The lumbar spine was the most commonly affected region, and 27 infections (26.2%) occurred at L4/5. The white blood cell count was normal in 61 children (59%), and the CRP level was normal in 43 (42%). Blood cultures were performed in 95 children, and were positive in eight (8%). A total of 20 children underwent culture of biopsy or aspiration material, which was positive in eight (40%). Methicillin-sensitive Staphylococcus aureus (MSSA) and Kingella ( K.) kingae were the most frequently isolated pathogens.

Conclusion

MSSA remains the most frequently isolated pathogen in children with primary pyogenic infection of the spine, but K. kingae should be considered as an important pathogen in children aged between six months and four years. Therefore, an empirical protocol for antibiotic treatment should be used, with consideration being made for the triphasic age distribution and specific bacteriological aetiology. In the near future, the results of polymerase chain reaction assay on throat swabs may allow the indirect identification of K. kingae spondylodiscitis in young children and thus aid early treatment. However, these preliminary results require validation by other prospective multicentre studies. Cite this article: Bone Joint J 2018;100-B:542-8.

Percutaneous CT-guided sacroiliac joint sampling for infection: aspiration, biopsy, and technique

OBJECTIVE

To evaluate methods of CT-guided sacroiliac joint sampling in patients with suspected infection.

MATERIALS AND METHODS

All CT-guided sacroiliac joint sampling procedures for suspected infection were reviewed for sampling type (aspiration, lavage aspiration, biopsy), microbiology results, and clinical and imaging follow-up. The primary gold standard was anatomic pathology. If pathology was not available, then positive blood culture with the same organism as SIJ sampling, imaging and clinical follow-up, or clinical follow-up only were used. Anterior and posterior joint distention was evaluated by MRI within 7 days of the procedure.

RESULTS

A total of 34 patients (age 39 ± 20 (range, 6-75) years; 21 F, 13 M) were included. Aspiration samples only were obtained in 13/34 (38%) cases, biopsy samples only in 9/34 (26%) cases, and both samples in 12/34 (35%) cases. There was an overall 54% sensitivity and 86% specificity. For the aspiration samples, sensitivity and specificity were 60 and 81%, respectively, compared to 45 and 90% for the biopsy samples. In cases with both samples, biopsy did not add additional microbial information. Seventeen (17/34, 50%) patients had an MRI. The anterior joint was more distended than the posterior joint in 15/17 (88%) of patients, and this difference was significant (P = 0.0003). All of these 17 patients had an attempted aspiration by a posterior approach; 6/17 (35%) resulted in a successful aspiration.

CONCLUSIONS

Aspiration of the sacroiliac joint has a higher sensitivity than biopsy and should always be attempted first. MRI may be helpful for procedure planning.

Lack of effect of antibiotics on biopsy culture results in vertebral osteomyelitis

We report a retrospective study of 173 patients with vertebral osteomyelitis evaluating the effect of antibiotics administered prior to percutaneous and open biopsy cultures. Antibiotics given prior to these biopsies did not have a significant effect on the yield of cultures.

CT-guided biopsy in suspected spondylodiscitis: microbiological yield, impact on antimicrobial treatment, and relationship with outcome

PURPOSE

To investigate the clinical impact of CT-guided biopsy, as performed in routine clinical practice, in patients with suspected spondylodiscitis on MRI in terms of culture yield, impact on antimicrobial treatment, and outcome.

METHODS

This study included 64 patients with MRI findings compatible with spondylodiscitis who underwent CT-guided biopsy.

RESULTS

Initial CT-guided biopsies were culture-positive in 20/64 (31.3%, 95% confidence interval [CI] 21.2-43.3%). Repeat CT-guided biopsies (after initial negative biopsy) were culture-positive in an additional 5/15 (33.3%, 95% CI 15.2-58.3%). Serum leukocytes, C-reactive protein, pre-biopsy use of antibiotics, neurological symptoms, MRI findings, vertebral height loss, and hyperkyphosis were not significantly different between culture-positive and culture-negative cases (P = 0.214-1.000); 75% (15/20) of initial CT-guided biopsies that were culture-positive provided additional information to clinicians for guiding antibiotic treatment. Sixty-two of 64 patients (96.9%, 95% CI 89.3-99.1%) would have been adequately treated if a strategy was followed that would subject all patients without clinical findings suspicious for "atypical" microorganisms and negative blood cultures to empirical antibiotics (i.e., clindamycin for coverage of Gram-positive bacteria) without using biopsy results to determine the optimal antibiotic regimen. Outcome within 6 months (development of neurologic or orthopedic complications, surgery, and death) was not significantly different (P = 0.751) between culture-positive and culture-negative patients.

CONCLUSIONS

Although CT-guided biopsies are culture-positive in a minority of cases, the majority of positive cultures are useful to tailor antibiotic treatment. Empirical treatment with clindamycin may cover almost all micro-organisms in positive biopsy specimens, provided patients are not immunocompromised. Outcome appears similar between culture-positive and culture-negative patients.

Spondylodiscitis: Diagnosis and Treatment Options

BACKGROUND

A recent population-based study from Denmark showed that the incidence of spondylodiscitis rose from 2.2 to 5.8 per 100 000 persons per year over the period 1995-2008; the age-standardized incidence in Germany has been estimated at 30 per 250 000 per year on the basis of data from the Federal Statistical Office (2015). The early diagnosis and treatment of this condition are essential to give the patient the best chance of a good outcome, but these are often delayed because it tends to present with nonspecific manifestations, and fever is often absent.

METHODS

This article is based on a systematic search of Medline and the Cochrane Library for the period January 2009 to March 2017. Of the 788 articles identified, 30 publications were considered.

RESULTS

The goals of treatment for spondylodiscitis are to eliminate infection, restore functionality of the spine, and relieve pain. Magnetic resonance imaging (MRI) remains the gold standard for the radiological demonstration of this condition, with 92% sensitivity and 96% specificity. It also enables visualization of the spatial extent of the infection and of abscess formation (if present). The most common bacterial cause of spondylodiscitis in Europe is Staphylococcus aureus, but tuberculous spondylodiscitis is the most common type worldwide. Antibiotic therapy is a pillar of treatment for spondylodiscitis and should be a part of the treatment in all cases. Neurologic deficits, sepsis, an intraspinal empyema, the failure of conservative treatment, and spinal instability are all indications for surgical treatment.

CONCLUSION

The quality of life of patients who have been appropriately treated for spondylodiscitis has been found to be highly satisfactory in general, although back pain often persists. The risk of recurrence increases in the presence of accompanying illnesses such as diabetes mellitus, renal failure, or undrained epidural abscesses.

Intensity of 18F-FDG PET Uptake in Culture-Negative and Culture-Positive Cases of Chronic Osteomyelitis

Microbiologic cultures are not infrequently negative in patients with a histopathologic diagnosis of chronic osteomyelitis. Culture-negative cases may represent low-grade infections with a lower metabolic activity than culture-positive cases. ¹⁸F-FDG PET could potentially detect such a difference. We determined whether the level of ¹⁸F-FDG PET uptake differs in patients with culture-negative and culture-positive osteomyelitis. We reviewed the clinical charts of 40 consecutive patients, who had diagnostic ¹⁸F-FDG PET for a suspected bone infection. Twenty-six patients were eligible with a confirmed diagnosis based on microbiologic cultures and/or histopathologic examination. Sixteen of 26 patients had chronic osteomyelitis. Eight of them had positive cultures, seven had negative cultures, and one patient had no cultures of the biopsy specimen. The patients with histologically and/or microbiologically proven osteomyelitis were correctly interpreted as true positive in the routine clinical reading of ¹⁸F-FDG PET images. There was no relationship between the level of ¹⁸F-FDG PET uptake and the presence of positive or negative bacterial cultures. The result favors the concept that that culture-negative cases of osteomyelitis are false-negative infections due to nonculturable microbes. ¹⁸F-FDG PET may help to confirm the presence of metabolically active infection in these patients and guide their appropriate treatment.

Yield of Image-Guided Needle Biopsy for Infectious Discitis: A Systematic Review and Meta-Analysis

BACKGROUND

Image-guided biopsy is routinely conducted in patients with suspected discitis, though the sensitivity reported in the literature ranges widely.

PURPOSE

We applied a systematic review and meta-analysis to estimate the yield of image-guided biopsy for infectious discitis.

DATA SOURCES

We performed a literature search of 4 data bases: PubMed, Cochrane CENTRAL Register of Controlled Trials, Embase.com, and Scopus from data base inception to March 2016.

STUDY SELECTION

A screen of 1814 articles identified 88 potentially relevant articles. Data were extracted for 33 articles, which were eligible if they were peer-reviewed publications of patients with clinical suspicion of discitis who underwent image-guided biopsy.

DATA ANALYSIS

Patients with positive cultures out of total image-guided biopsy procedures were pooled to estimate yield with 95% confidence intervals. Hypothesis testing was performed with an inverse variance method after logit transformation.

DATA SYNTHESIS

Image-guided biopsy has a yield of approximately 48% (793/1763), which is significantly lower than the open surgical biopsy yield of 76% (152/201; P < .01). Biopsy in patients with prior antibiotic exposure had a yield of 32% (106/346), which was not significantly different from the yield of 43% (336/813; P = .08) in patients without prior antibiotic exposure.

LIMITATIONS

The conclusions of this meta-analysis are primarily limited by the heterogeneity of the included studies.

CONCLUSIONS

Image-guided biopsy has a moderate yield for the diagnosis of infectious discitis, which is significantly lower than the yield of open surgical biopsy. This yield is not significantly affected by prior antibiotic use.