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

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.

[Spondylodiscitis : Current strategies for diagnosis and treatment]

Spondylodiscitis is a severe infectious disease of the intervertebral discs and of the adjacent parts of the vertebral bodies, culminating in destruction of the mobile segment. It is accompanied by a mortality rate of approximately 15%. Severe courses of the disease can also lead to abscess formation and dispersal of sepsis. Malpositioning of the axis organ and deficits in neurological function up to paraplegia are also possible complications. Timely diagnostics and targeted therapy contribute to minimizing the risk of significant health disorders. This review article gives a summary of important algorithms in the diagnostics and treatment and discusses them against the background of currently available literature. According to the current state of knowledge the surgical treatment of spondylodiscitis provides many advantages and is therefore the method choice, even if a conservative approach can be successful in selected cases. The endpoints of treatment are cleansing of the infection with normalization of laboratory parameters of inflammation and the osseous fusion of the mobile segment.

Magnetic resonance imaging of bacterial and tuberculous spondylodiscitis with associated complications and non-infectious spinal pathology mimicking infections: a pictorial review

Magnetic resonance (MR) imaging plays an important role in the evaluation of bacterial and tuberculous spondylodiscitis and associated complications. Owing to its high sensitivity and specificity, it is a powerful diagnostic tool in the early diagnosis of ongoing infections, and thus provides help in prompt initiation of appropriate, therapy which may be medical or surgical, by defining the extent of involvement and detection of complications such as epidural and paraspinal abscesses. More specifically, MR imaging helps in differentiating bacterial from tuberculous infections and enables follow up of progression or resolution after appropriate treatment. However, other non-infectious pathology can demonstrate similar MR imaging appearances and one should be aware of these potential mimickers when interpreting MR images. Radiologists and other clinicians need to be aware of these potential mimics, which include such pathologies as Modic type I degenerative changes, trauma, metastatic disease and amyloidosis. In this pictorial review, we will describe and illustrate imaging findings of bacterial and tuberculous spondylodiscitis, their complications and non-infectious pathologies that mimic these spinal infections.

The role of minimally invasive spine surgery in the management of pyogenic spinal discitis

Background:

Diagnostic yields for spondylodiscitis from CT guided biopsy is low. In the recent years, minimally invasive surgery (MIS) has shown to have a low morbidity and faster recovery. For spinal infections, MIS surgery may offer an opportunity for early pain control while obtaining a higher diagnostic yield than CT-guided biopsies. The aim of this study was to review our patients who underwent MIS surgery for spinal infection and report outcomes.

Methods:

A retrospective review of seven patients who underwent MIS decompression and/or discectomy in the setting of discitis, osteomyelitis, spondylodiscitis, and/or an epidural abscess was identified. Patient data including symptoms, visual analog score (VAS), surgical approach, antibiotic regimen, and postoperative outcomes were obtained.

Results:

Of the 7 patients, 5 patients had lumbar infections and two had thoracic infections. All seven patients improved in VAS immediately after surgery and at discharge. The average VAS improved by 4.4 ± 1.9 points. An organism was obtained in 6 of the 7 (85%) patients by the operative cultures. All patients made an excellent clinical recovery without the need for further spine surgery. All patients who received postoperative imaging on follow-up showed complete resolution or dramatically improved magnetic resonance imaging changes. The follow-up ranged from 2 to 9 months.

Conclusions:

MIS surgery provides an opportunity for early pain relief in patients with discitis, osteomyelitis, spondylodiscitis, and/or epidural abscess by directly addressing the primary cause of pain. MIS surgery for discitis provides a higher diagnostic yield to direct antibiotic treatment. MIS surgery results in good long-term recovery.

Computed tomography–guided percutaneous biopsy for vertebral neoplasms: a department's experience and hybrid biopsy technique to improve yield

OBJECTIVE

Recent articles have identified the poor diagnostic yield of percutaneous needle biopsy for vertebral osteomyelitis. The current study aimed to confirm the higher accuracy of CT-guided spinal biopsy for vertebral neoplasms and to identify which biopsy technique provides the highest yield.

METHODS

Over a 9-year period, the radiology department at University Hospitals Case Medical Center performed 222 CT-guided biopsies of vertebral lesions, of which clinicians indicated a concern for vertebral neoplasms in 122 patients. A retrospective chart review was performed to confirm the higher sensitivity of the percutaneous intervention for vertebral neoplasms.

RESULTS

A core sample was obtained for all 122 biopsies of concern (100.0%). Only 6 cases (4.9%) were reported as nondiagnostic per histological sampling, and 12 cases (9.8%) were negative for disease. The question of vertebral neoplastic involvement warrants follow-up, and the current study was able to determine the subsequent diagnosis of each lesion. Of the 122 total, 94 (77.0%) core samples provided true-positive results, and the sensitivity of core biopsy measured 87.9%. The technical approach did not demonstrate any significant difference in diagnostic yield. However, when the vertebral cortex was initially pierced with a coaxial bone biopsy system and subsequently a 14-gauge spring-loaded cutting biopsy needle was coaxially advanced into lytic lesions, 14 true positives were obtained with a corresponding sensitivity of 100.0%.

CONCLUSIONS

This study confirms the higher sensitivity of image-guided percutaneous needle biopsy for vertebral neoplasms. In addition, it demonstrates how the use of a novel cutting needle biopsy approach, performed coaxially through a core biopsy track, provides the highest yield.

Role of Operative or Interventional Radiology-Guided Cultures for Osteomyelitis

BACKGROUND AND OBJECTIVE

Acute hematogenous osteomyelitis (AHO) is a severe infection in children. Drainage of purulent collections in bones provides specimens for culture as well as therapeutic benefit. Interventional radiology (IR)-guided procedures may serve as a less invasive means of culture in select patients. We examined the impact of IR and surgically obtained cultures in the diagnosis and management of AHO.

METHODS

A retrospective review of cases of AHO was performed from 2011 to 2014. Patients with chronic disease, orthopedic hardware, puncture wounds, or an infected contiguous focus were excluded.

RESULTS

A total of 250 cases met inclusion criteria. Blood cultures were positive in 107 of 231 cases (46.3%), and 123 of 150 patients had positive cultures (82%) obtained by orthopedic surgery. Of these 123 patients, 62 (50.4%) had organisms identified only through operating room (OR) cultures. Of the 66 patients who had cultures obtained by IR, 34 (51.5%) had positive IR cultures. For those with positive IR cultures, 18 (52.9%) had negative blood cultures. Among the 80 patients with negative blood culture and positive OR/IR culture, the results changed antibiotic therapy in 68 (85%) patients.

CONCLUSIONS

IR or OR culture was the only means of identifying a pathogen in 80 of 216 cases (37%), and in >80% changed medical management. IR can be used effectively to obtain bone cultures in children with AHO not requiring open surgical drainage. Further research is needed to better understand the optimal utilization of IR and OR culture in pediatric AHO.

Diagnostic contribution of a second percutaneous needle biopsy in patients with spontaneous diskitis and negative blood cultures and first biopsy

OBJECTIVES

The primary objective was to assess the diagnostic contribution of a second percutaneous needle biopsy in patients with spontaneous diskitis and negative findings from blood cultures and the first biopsy. We also assessed the sensitivity of the first biopsy and the diagnostic contribution of post-biopsy blood cultures.

METHODS

Multicenter retrospective study of patients managed between 2004 and 2014. We excluded patients with postoperative diskitis.

RESULTS

We identified 63 patients with spontaneous diskitis, negative blood cultures, and at least one percutaneous needle biopsy during the study period. The first biopsy established the diagnosis in 33 (52%) patients. Of the 30 remaining patients, 10 (33%) had a second biopsy, which was positive in 6 (60%), and 20 (67%) received probabilistic antibiotic therapy. There were 8 positive blood cultures after the first biopsy but, among them, 7 occurred in biopsy-positive patients. Biopsy yield varied with the guidance method (needle guidance software or imaging by computed tomography and/or fluoroscopy) and operators. Antibiotic therapy within the 6months preceding the first biopsy was significantly associated with having a negative first biopsy (15/30 versus 7/33; odds ratio, 3.13; 95% confidence interval, 1.07-9.13; P<0.05).

CONCLUSION

In our study, a second needle biopsy was useful, providing the bacteriological diagnosis in 60% of cases of spontaneous diskitis with negative findings from blood cultures and the first biopsy.

Imaging Psoas Sign in Lumbar Spinal Infections: Evaluation of Diagnostic Accuracy and Comparison with Established Imaging Characteristics

BACKGROUND AND PURPOSE

Lumbar discitis-osteomyelitis has imaging characteristics than can overlap with noninfectious causes of back pain. Our aim was to determine the added accuracy of psoas musculature T2 hyperintensity (imaging psoas sign) in the MR imaging diagnosis of lumbar discitis-osteomyelitis.

MATERIALS AND METHODS

This retrospective case-control study evaluated lumbar spine MR imaging examinations, during a 30-month period, that were requested for the evaluation of discitis-osteomyelitis. Of this pool, 50 age-matched control patients were compared with 51 biopsy-proved or clinically diagnosed patients with discitis-osteomyelitis. Two reviewers, blinded to the clinical information, assessed the randomly organized MR imaging examinations for abnormalities of the psoas musculature, vertebral bodies, discs, and epidural space.

RESULTS

Psoas T2 hyperintensity demonstrated a high sensitivity (92.1%; 95% CI, 80%-97.4%) and specificity (92%; 95% CI, 80%-97.4%), high positive likelihood ratio (11.5; 95% CI, 4.5-29.6), low negative likelihood ratio (0.09; 95% CI, 0.03-0.20), and individual area under the receiver operating characteristic curve of 0.92; 95% CI, 0.87-0.97. Identification of psoas T2 abnormality significantly improved (P = .02) the diagnostic accuracy of discitis-osteomyelitis in noncontrast examinations from an area under the receiver operator characteristic curve of the established variables (vertebral body T2 and T1 signal, endplate integrity, disc T2 signal, and disc height) from 0.93 (95% CI, 0.88-0.98) to 0.98 (95% CI, 0.96-1.0). Psoas T2 abnormalities also had the highest interobserver reliability with a κ coefficient of 0.78 (substantial agreement).

CONCLUSIONS

Psoas T2 hyperintensity, the imaging psoas sign, is highly correlated with discitis-osteomyelitis. T2 hyperintensity in the psoas musculature, particularly when there is clinical suspicion of spinal infection, improves the diagnostic accuracy of discitis-osteomyelitis compared with routine noncontrast variables alone.

Vertebral osteomyelitis in adults: an update

INTRODUCTION

The incidence of vertebral osteomyelitis is increasing, attributed to an ageing population with inherent co-morbidities and improved case ascertainment.

SOURCES OF DATA

References were retrieved from the PubMed database using the terms 'vertebral osteomyelitis' and 'spondylodiscitis' between January 1, 2009 and April 30, 2014 published in English as checked in May 2014 (>1000 abstracts checked).

AREAS OF AGREEMENT

Blood cultures and whole spine imaging with magnetic resonance imaging are essential investigations. Thorough debridement is the mainstay of surgical management, although placing metalwork in active infection is becoming increasingly common.

AREAS OF CONTROVERSY

The extent of pursuing spinal biopsies to determine aetiology, antimicrobial choices and duration, monitoring the response to treatment, and surgical techniques and timing all vary widely in clinical practice with heterogeneous studies limiting comparisons. Surgery, rather than conservative approaches, is being proposed as the default management choice, because it can, in carefully selected patients, offer faster reduction in pain scores and improved quality of life.

AREAS TIMELY FOR DEVELOPING RESEARCH

Further studies are needed to define the most effective technique for spinal biopsies to maximize determining aetiology. High-quality trials are required to provide an evidence base for both the medical and surgical management of vertebral osteomyelitis, including challenging medical management as the default option.

Does Pathogen Identification Influence the Clinical Outcomes in Patients With Pyogenic Spinal Infections?

STUDY DESIGN

Retrospective study.

OBJECTIVE

To study the clinical outcomes of patients suffering from pyogenic spinal infections (PSI), by comparing the outcomes of patients with an identified microbiological agent with those of patients without an identified pathogen.

SUMMARY OF BACKGROUND DATA

PSI is associated with significant risks for morbidity and mortality. Specific antibiotic treatment has been considered a key to successful medical treatment; however, clinicians frequently treat patients with PSI without an identified agent. A paucity of data is available comparing the clinical outcomes of patients with or without an identified pathogen.

MATERIALS AND METHODS

The records of 97 consecutive patients discharged from a University Hospital with the diagnosis of PSI during a 14-year period were retrospectively reviewed. Patients' demographics, etiological agent, comorbidities, site of infection, white blood cell count, erythrocyte sedimentation rate, C-reactive protein at the time of presentation, neurological impairment, length of hospital stay, and mortality were registered to compare the clinical outcomes of patients with an identified pathogen with those of patients without an identified agent.

RESULTS

The causative organism was identified in 74 patients (76.3%). Patients with microbiological diagnosis were younger, and a larger percentage of them exhibited elevated C-reactive protein value; however, they were not different from those without an identified agent in terms of sex, site of infection, comorbidities, and the presence of a concomitant infection. Our study could not demonstrate different neurological outcomes, length of stay, or mortality rates among the 2 groups.

CONCLUSIONS

In a large series of patients with PSI, we did not demonstrate differences in clinical outcomes using empirical antibiotics in patients without an identified pathogen compared with patients with an identified microbiological agent receiving specific antibiotics. Future prospective multicenter studies should be conducted to obtain an answer to this important clinical question.

Image guided interventions in spinal infections

Spinal infections are challenging to diagnose and represent a life-threatening medical condition. Diagnosis is often delayed because of nonspecific accompanying symptoms. The role of interventional neuroradiology in spinal infection is double: diagnostic and therapeutic, consisting substantially of 2 main procedures, represented by spine biopsies and positioning of percutaneous drainage, which represent a minimally invasive, faster and more cost-effective alternative to open surgery procedures. This article will focus on the available state-of-the-art techniques to perform discovertebral image-guided biopsies in case of suspected infections and on image-guided placement of percutaneous drainage to treat infectious collections of the spine and paravertebral structures.

Interest of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography for the diagnosis of relapse in patients with spinal infection: a prospective study

Relapse after treatment of a spinal infection is infrequent and difficult to diagnose. The aim of this study was to assess the diagnostic performance of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in this setting. Thirty patients (21 men, nine women; median age 61.2 years) with a suspected spinal infection relapse were prospectively included between March 2010 and June 2013. The initial diagnosis of spinal infection was confirmed by positive bacterial cultures. The patients underwent [(18)F]FDG PET/CT and magnetic resonance imaging (MRI) 1 month after antibiotic treatment interruption. PET/CT data were interpreted both visually and semi-quantitatively (SUVmax). The patients were followed for ≥12 months and the final diagnosis of relapse was based on new microbiological cultures. Seven patients relapsed during follow up. Sensitivity, specificity, positive predictive value and negative predictive value were 66.6%, 61.9%, 33.3% and 86.6%, respectively for MRI and 85.7, 82.6, 60.0 and 95.0 for PET/CT. Although these values were higher for PET/CT than for MRI, the difference was not statistically significant (p=0.3). [(18)F]FDG PET/CT may be useful for diagnosing a relapse of spinal infections, in particular if metallic implants limit the performance of MRI.

Staphylococcus aureus-Associated Musculoskeletal Infections

Musculoskeletal infections caused by Staphylococcus aureus are among the most difficult-to-treat infections. S. aureus osteomyelitis is associated with a tremendous disease burden through potential for long-term relapses and functional deficits. Although considerable advances have been achieved in diagnosis and treatment of osteomyelitis, the management remains challenging and impact on quality of life is still enormous. S. aureus acute arthritis is relatively seldom in general population, but the incidence is considerably higher in patients with predisposing conditions, particularly those with rheumatoid arthritis. Rapidly destructive course with high mortality and disability rates makes urgent diagnosis and treatment of acute arthritis essential. S. aureus pyomyositis is a common disease in tropical countries, but it is very seldom in temperate regions. Nevertheless, the cases have been increasingly reported also in non-tropical countries, and the physicians should be able to timely recognize this uncommon condition and initiate appropriate treatment. The optimal management of S. aureus-associated musculoskeletal infections requires a strong interdisciplinary collaboration between all involved specialists.

Is Biopsying the Paravertebral Soft Tissue as Effective as Biopsying the Disk or Vertebral Endplate? 10-Year Retrospective Review of CT-Guided Biopsy of Diskitis-Osteomyelitis

OBJECTIVE

The purpose of this study was to determine whether there is a difference in biopsying bone (endplate), disk, or paravertebral soft tissue to culture the pathogenic organism causing diskitis-osteomyelitis.

MATERIALS AND METHODS

A retrospective review was conducted of 111 spinal biopsies performed between 2002 and 2011. Pathologic examination was used as the reference standard for detecting diskitis-osteomyelitis. Microbiologic yield, sensitivity, and specificity were calculated. The yields for different groups were compared by use of Fisher exact test. The analysis was repeated with biopsy samples from patients not being treated with antibiotics at the time of biopsy.

RESULTS

A total of 122 biopsy specimens were obtained from 111 spinal biopsy procedures on 102 patients. Overall, 27 (22%) biopsies were performed on the endplate-disk, 61 (50%) on the disk only, and 34 (28%) on paravertebral soft tissue only. The microbiologic yield was 36% for all biopsies, 19% for endplate-disk biopsies, 39% for disk-only biopsies, and 44% for soft-tissue biopsies. The sensitivity and specificity of the microbiologic results for all specimens were 57% and 89%; endplate-disk, 38% and 86%; disk only, 57% and 89%; and paravertebral soft tissue, 68% and 92%. There was no statistically significant difference between the yields of the endplate-disk, disk-only, and paravertebral soft-tissue biopsies.

CONCLUSION

Paravertebral soft-tissue changes, when present, may be considered a viable target for biopsy in cases of diskitis-osteomyelitis, even in the absence of a paravertebral abscess.

2015 Infectious Diseases Society of America (IDSA) Clinical Practice Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adultsa

These guidelines are intended for use by infectious disease specialists, orthopedic surgeons, neurosurgeons, radiologists, and other healthcare professionals who care for patients with native vertebral osteomyelitis (NVO). They include evidence and opinion-based recommendations for the diagnosis and management of patients with NVO treated with antimicrobial therapy, with or without surgical intervention.

Which tissues are best for microbiological diagnosis in patients with pyogenic vertebral osteomyelitis undergoing needle biopsy?

Identification of the causative microorganism is important in the management of pyogenic vertebral osteomyelitis (PVO). The aim of this study was to investigate whether culture positive rates differ between needle biopsy sites in patients with PVO, and which tissues are best for microbiological diagnosis. Between January 2005 and December 2013, we conducted a retrospective cohort study of PVO patients who had soft-tissue abscesses (paraspinal or psoas abscesses) and who received needle biopsy for microbiological diagnosis. Needle biopsy sites were classified into two anatomical categories: vertebral bodies, or soft tissues (intervertebral discs, paraspinal abscesses, or psoas abscesses). A generalized estimating equation model was developed to identify factors associated with tissue-culture positivity. During the study period a total of 136 tissues were obtained by needle biopsy from 128 PVO patients with soft-tissue abscesses. The culture positive rates of vertebral bodies and soft tissues were 39.7% (29/73), and 63.5% (40/63), respectively (p < 0.05). In a multivariate analysis, male gender (adjusted odds ratio (aOR) 2.24, 95% CI 1.00-5.02), higher C-reactive protein (aOR 1.07, 95% CI 1.01-1.15), positive blood culture (aOR 2.57, 95% CI 1.01-6.59), and soft tissues as biopsy site compared with vertebral bodies (aOR 2.28, 95% CI 1.08-4.78) were independent factors associated with tissue culture positivity. Soft tissues were the best sites for microbiological diagnosis in PVO patients undergoing needle biopsy.

Computed tomography-guided percutaneous biopsy for vertebral osteomyelitis: a department's experience

OBJECT

Vertebral osteomyelitis has been reported to occur in approximately 0.2-2 cases per 100,000 annually. Elevated laboratory values such as erythrocyte sedimentation rate and C-reactive protein suggest inflammatory etiologies. Different imaging modalities, from radiography and CT scanning to nuclear medicine imaging and contrastenhanced MRI, can be employed to evaluate for osteomyelitis. Although MRI has a strong sensitivity and specificity for vertebral osteomyelitis, obtaining histological and microbiological samples remains the gold standard in diagnosis. Therapy can be geared toward the specific pathogen cultured, thereby preventing the need surgical intervention in the majority of cases. However, recent reports have questioned the percentage yield of image-guided percutaneous biopsy even when there is a high clinical suspicion for vertebral osteomyelitis.

METHODS

After obtaining institutional review board approval, the authors performed a chart review of patients who had undergone image-guided percutaneous bone biopsies at University Hospitals Case Medical Center in Cleveland, Ohio. Data were filtered for patients in whom a biopsy sample of a vertebral body/disc was obtained. A total of 213 procedures were performed, of which clinicians indicated a concern for infection in 84, infection or neoplasm in 13, and a noninfectious etiology (the majority being neoplasms) in the remaining 116.

RESULTS

Histological examination provided positive results in 25 (41.0%) of the 61 samples collected for suspected cases of osteomyelitis. Microbiology samples were less predictive, with only 16 of the 84 samples collected, or 19.0%, yielding a positive result. In 10 patients there were positive blood and/or urine cultures. Of these, 8 samples (80%) demonstrated the same pathogen identified by biopsy (for the remaining 2 positive systemic cultures, no pathogen was identified by the percutaneous intervention). In other words, half of the 16 cases that provided microbiological results from biopsy demonstrated the same results by systemic cultures. However, 89 (76.7%) of the 116 samples collected with the primary concern of neoplasm yielded results.

CONCLUSIONS

Image-guided percutaneous biopsy for vertebral osteomyelitis demonstrates an extremely low probability of identifying specific microbes. Blood or urine cultures concurrently identified culprit pathogens in 50% of positive biopsy cultures. Therefore, in only 8 (9.5%) of 84 biopsies did the biopsy results provide additional information to clinicians as to the pathological microorganism present and how treatment might need to be adjusted.

The utility of image-guided percutaneous needle aspiration biopsy for the diagnosis of spontaneous vertebral osteomyelitis: a systematic review and meta-analysis

BACKGROUND CONTEXT

Spontaneous vertebral osteomyelitis (SVOM) is mostly acquired via hematogenous seeding. Diagnosis of SVOM is often delayed because of the insidious nature and rarity of this disease. The microbiological yield of image-guided needle biopsy varies between 36% and 91%. The utility and accuracy of this procedure have not been systematically reviewed.

PURPOSE

To systematically review and assess the diagnostic accuracy of image-guided spinal biopsy for SVOM in adults when compared with combined reference standards.

STUDY DESIGN

A systematic review and meta-analysis.

SAMPLE

Seven retrospective studies involving 482 patients with clinical and/or radiologic suspicion of SVOM who underwent image-guided spinal biopsy were included.

OUTCOME MEASURES

The primary outcome measure was diagnostic odds ratio (DOR). Other outcomes included likelihood ratio of a positive test (LRP), likelihood ratio of a negative test (LRN), sensitivity, and specificity.

METHODS

We searched in six medical databases through September 1, 2013 for studies evaluating the performance of image-guided spinal biopsy for SVOM with no limits on language or publication date. Combined reference standards, which included histopathologic findings consistent with vertebral osteomyelitis, identifications of pathogens from open surgery and/or blood cultures, and/or evidence of clinical and radiologic improvement after empiric antimicrobial therapy, were used for comparison. The random-effect model was used for meta-analysis. Two reviewers independently selected the studies.

RESULTS

Three hundred fifty-eight potentially relevant studies were identified. Seven studies were included in our analysis. Two studies that used only single reference standard were excluded in the sensitivity analysis, and five studies involving 352 patients were pooled. Image-guided spinal biopsy had a DOR of 45.50 (95% confidence interval [CI], 13.66-151.56), an LRP of 16.76 (95% CI, 5.51-50.95), an LRN of 0.39 (95% CI, 0.24-0.64), a sensitivity of 52.2% (95% CI, 45.8-58.5), and a specificity of 99.9% (95% CI, 94.5-100). This is based on the assumption that combined reference standards are a valid standard for comparison.

CONCLUSIONS

Image-guided spinal biopsy is highly specific and performs well in predicting SVOM, but has a moderate accuracy for ruling out this diagnosis. This procedure should be considered in the diagnostic work-up of adults suspected with SVOM.

Therapeutic impact of organism isolation in management of patients with pyogenic vertebral osteomyelitis

In management of patients with pyogenic vertebral osteomyelitis, organism isolation by biopsy is generally considered to be of primary importance when constructing a treatment plan. In our clinical practice, however, patients can be successfully treated even without identifying the organisms. The objective of this study is to review our clinical experiences and clarify the therapeutic impact of organism isolation. Forty patients who were conservatively managed in our institution constituted the base of this study. The average follow-up period was 16.7 months. Among the study subjects, 13 patients underwent percutaneous needle biopsy and the organism was identified in 6 patients. Additionally, the organism was isolated from the sample obtained from blood and possible foci in 10 patients. In total, the causative organism was identified in 15 of the 40 patients (37.5%). Patients were divided into two groups based on whether the organism was identified by culture (Groups A and B, with and without organism isolation respectively). The duration of antibiotic therapy was not significantly different between the groups (Group A: 4.8 ± 1.6 months, Group B: 4.3 ± 2.1 months), while subsequent mortalities in Group A and B were 13.3% and 8% without significant intergroup difference. Organism isolation did not productively help select the effective antibiotics and reduce the treatment period or mortality rate in treatment of patients with pyogenic vertebral osteomyelitis. Therefore, current strategic antibiotic therapy may be effective in eradicating infection even without identification of the causative organism in treatment of patients with pyogenic vertebral osteomyelitis.

Diagnostic yield of CT-guided sampling in suspected sternoclavicular joint infection

OBJECTIVE

To determine the prevalence of infection diagnosed by percutaneous computed tomography (CT)-guided sternoclavicular (SC) sampling in cases of suspected joint infection.

MATERIALS AND METHODS

A retrospective search was performed in reports of SC joint CT-guided biopsies in adults from July 1992 to July 2012. We reviewed medical records, radiology, microbiology, laboratory, and surgical reports. A positive result was defined as demonstration of a pathogenic organism, either by microscopy or growth in culture, confirming the diagnosis of SC joint infection. A negative result was defined as the absence of such findings. Patients in whom sampling was unsuccessful or not subjected to microbiology were excluded. In addition, CT images were reviewed by the consensus of two musculoskeletal radiologists.

RESULTS

A total of 41 patients (mean age 57.1 years) underwent CT-guided SC joint sampling, 27 of whom underwent microbiology studies. Sampling was performed using core biopsy alone in 19%, fine needle aspiration alone in 44%, and aspiration combined with core biopsy in 37%. Positive results were found in 52% (14/27) of patients. Related diseases and predisposing conditions for infection were found in 79% of positive patients. Negative results were found in 48% (13/27) of patients. There were no procedure-related complications. The dominant CT findings were soft tissue swelling (negative group), and effusion and/or capsular hypertrophy/distension (positive group).

CONCLUSIONS

CT-guided sampling is a safe procedure with positive microbiological cultures in slightly more than half of cases.

Evaluacion de la biopsia transpedicular guiada por TAC

OBJETIVO: Valorar la utilidad de la biopsia transpedicular percutánea guiada por Tomografía Axial Computarizada en conjunto con la sistematización de estudios como pruebas diagnósticas de la etiología de la destrucción vertebral. MÉTODOS: Estudio de serie de casos prospectivo transversal de 21 pacientes a los que se les realizó biopsia transpedicular percutánea guiada por Tomografía Axial Computarizada y estudios de laboratorio y gabinete de marzo a julio del 2011, para evaluar su utilidad en el diagnóstico de destrucción vertebral. RESULTADOS: Fueron 21 pacientes, 14 hombres y 7 mujeres, con edad media de 59,2 años, cuyos niveles más afectados estuvieron en L1, L2 y L3. El reporte de la biopsia tuvo una precisión diagnóstica del 90,4%. En 2 casos se realizó correlación clínica entre biopsia y sistematización de estudios para obtener el diagnóstico. CONCLUSIÓN: La biopsia guiada por Tomografía Axial Computarizada es una técnica sencilla, útil, de bajo costo y eficaz en el estudio de la destrucción vertebral; la sistematización de estudios permite corroborar el diagnóstico de la biopsia.

Imaging of spine infection

This article reviews the imaging and relevant clinical details of infection of the extradural spine. Spine infections are increasing in incidence and in frequency of diagnosis. They are clinically important despite their relative rarity, because they may be life-threatening, and because early diagnosis leads to improved outcomes. The focus is on pyogenic spondylodiscitis. The also typically pyogenic conditions of epidural and subdural abscess, facet joint infection, and pyomyositis are discussed. Nonpyogenic, granulomatous infections are also addressed. Magnetic resonance imaging is emphasized. The radiologist's role in performing minimally invasive sampling procedures is highlighted.

[Spondylodiscitis]

Despite highly sensitive imaging techniques, the diagnosis and treatment of spondylodiscitis are often delayed due to a lack of specific symptoms with back pain as the presenting complaint. Late diagnosis and neurological involvement at the time of diagnosis are risk factors for long-term neurological deficits. Unremitting back pain with signs of inflammation should give reason to suspect spondylodiscitis and to rule it out by imaging, especially if risk factors such as diabetes mellitus, malignant neoplasms or immunosuppression are present. Magnetic resonance imaging (MRI) is the imaging procedure of choice with high sensitivity and specificity and typically shows hypointense adjacent vertebrae on T1-weighted images with hyperintense signal on short tau inversion recovery (STIR) sequences and hyperintense disc spaces on T2-weighted images.

Distribution of HIV-1 in the genomes of AIDS patients

The localization of HIV-1 proviruses in compositional DNA fractions from 27 AIDS patients during the chronic phase of the disease with depletion of CD4+ and different levels of viremia showed the following. (1) At low viremia, proviruses are predominantly localized in the GC-richest isochores, which are characterized by an open chromatin structure; this result mimics findings on HIV-1 integration in early infected cells in culture. (2) At higher viremia, an increased distribution of proviruses in GC-poor isochores (which match the GC poorness of HIV-1) was found; this suggests a selection of cells in which the 'isopycnic' localization leads to a higher expression of proviruses and, in turn, to higher viremia. (3) At the highest viremia, integrations in GC-rich isochores are often predominant again, but generally not at the same level as in (1); this may be the consequence of new integrations from the extremely abundant RNA copies.