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

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.

Microbial spectrum, patient-specific factors, and diagnostics in implant-related postoperative spondylodiscitis

Aims

Implant-related postoperative spondylodiscitis (IPOS) is a severe complication in spine surgery and is associated with high morbidity and mortality. With growing knowledge in the field of periprosthetic joint infection (PJI), equivalent investigations towards the management of implant-related infections of the spine are indispensable. To our knowledge, this study provides the largest description of cases of IPOS to date.

Methods

Patients treated for IPOS from January 2006 to December 2020 were included. Patient demographics, parameters upon admission and discharge, radiological imaging, and microbiological results were retrieved from medical records. CT and MRI were analyzed for epidural, paravertebral, and intervertebral abscess formation, vertebral destruction, and endplate involvement. Pathogens were identified by CT-guided or intraoperative biopsy, intraoperative tissue sampling, or implant sonication.

Results

A total of 32 cases of IPOS with a mean patient age of 68.7 years (37.6 to 84.1) were included. Diabetes, age > 60 years, and history of infection were identified as risk factors. Patient presentation upon admission included a mean body temperature of 36.7°C (36.1 to 38.0), back pain at rest (mean visual analogue scale (VAS) mean 5/10) and when mobile (mean VAS 6/10), as well as elevated levels of CRP (mean 76.8 mg/l (0.4 to 202.9)) and white blood cell count (mean 9.2 units/nl (2.6 to 32.8)). Pathogens were identified by CT-guided or conventional biopsy, intraoperative tissue sampling, or sonication, and Gram-positive cocci presented as the most common among them. Antibiotic therapy was established in all cases with pathogen-specific treatment in 23 (71.9%) subjects. Overall 27 (84.4%) patients received treatment by debridement, decompression, and fusion of the affected segment.

Conclusion

Cases of IPOS are rare and share similarities with spontaneous spondylodiscitis. While procedures such as CT-guided biopsy and sonication are valuable tools in the diagnosis of IPOS, MRI and intraoperative tissue sampling remain the gold standard. Research on known principles of PJI such as implant retention versus implant exchange need to be expanded to the field of spine surgery.

Conservative treatment may be still considered a viable therapeutic option for patients with spontaneous non-specific pyogenic spondylodiscitis. A retrospective audit study of 47 patients

Background

Spontaneous non-specific pyogenic spondylodiscitis (SNPS) is a rare medical condition, whose optimal treatment remains controversial. We evaluated the multidisciplinary protocol implemented at our department for the conservative treatment of patients with SNPS.

Methods

Patients with lumbar or thoracic SNPS, whose treatment was initiated conservatively and had at least six months of follow-up, were enrolled in this retrospective audit study. Patients with specific, postoperative, or iatrogenic spondylodiscitis or necessitating immediate operative treatment were excluded. The location of the infection, initial symptoms, co-morbidities, pathogens, duration of antibiotic treatment, hospitalization and follow-up, and outcome were retrieved. The visual analogue scale (VAS) score was used to register pain improvement after treatment.

Results

Between January 2011 and December 2021, forty-seven patients (male: 26, mean age: 68.5 years) with SNPS (lumbar: 29, thoracic: 18) were hospitalized. The main co-morbidity was diabetes mellitus (23 patients). Pain was the predominant (46 patients), and fever was the second most common (19 patients) symptom. The most frequent causative microorganism was staphylococcus aureus (29 patients); no pathogen was identified in ten patients. The mean hospitalization duration for patients completing their conservative treatment (43/47) was 27 (range: 22-41) days. They received antibiotics for a mean period of 23 days intravenously (range: 21-29), 23.8 days per os (range: 21-35), and 46.8 days in total (range: 42-63). Conservative treatment was discontinued in two females. Two male patients died due to septic shock. The mean follow-up was 11.5 months (range: 6-15). During follow-up, no one developed any neurologic deficit and/or recurrence. There was a significant improvement in the mean VAS, from 8.3 ± 0.8 pre-treatment to 1.6 ± 0.5 at the latest follow-up (p <0.001).

Conclusions

Although treatment is gradually shifting towards surgical intervention, conservative therapeutic management of SNPS patients with antibiotic administration, bed rest, and careful mobilization remains a viable and efficacious option. HIPPOKRATIA 2023, 27 (2):106-111.

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.

Distribution of Underlying Causative Organisms, Patient Age, and Survival in Spontaneous spondylodiscitis with Special Focus on Elderly Patients

BACKGROUND AND OBJECTIVE

 spondylodiscitis is becoming a more frequently encountered diagnosis in our clinical practice. Multimorbid and especially older patients build up a relevant portion of cases. The goal of our study was to evaluate our clinical data and to reveal specifics concerning elderly patients with spontaneous spondylodiscitis.

PATIENTS AND METHODS

 We retrospectively analyzed clinical data for the years from 2012 to 2014. The search was conducted on the basis of the International Classification of Diseases, 10th Revision (ICD-10) diagnoses for spondylodiscitis. Postoperative infections were not included in this study. All cases were evaluated in terms of infectious agents (in blood culture and/or computerized tomography [CT]-guided or surgical biopsy), age, and overall survival.

RESULTS

 Fifty-one patients with spontaneous spondylodiscitis were identified. The most frequent pathogen was methicillin-sensitive Staphylococcus aureus (MSSA; n = 21; 41.17%). Escherichia coli and S. epidermidis were each found in four patients each (7.84%). Methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa, and S. hominis were found in three cases (5.88%). Other bacteria were found in one case (each 1.96 %). In 12 cases, there was no bacteria growth (23.53%). One of these patients revealed to have a tuberculosis infection, diagnosed after the study period (in 2015). Two-thirds of the patients were ≥65 years old (n = 34). All three patients with MRSA were >65 years old. Three of seven patients <50 years had IV drug abuse (42.86%). In these patients, rather rare infectious agents for spondylodiscitis were found (P. aeruginosa, S. hominis, Citrobacter). Mortality was 7.84% (n = 4). All of these patients were ≥67 years old, three of four (75%) were ≥75 years old.

CONCLUSION

 Our study of spontaneous spondylodiscitis showed a stronger representation of older patients (>65 years). Lethal outcome exclusively concerned the older age group. S. aureus was the most frequent pathogen as shown previously. MRSA infections might be more common in the older age group. Rare causative organisms mainly occurred in patients with iv drug abuse. Further evaluation through randomized multicenter studies focusing on the different subgroups and comorbidities in larger populations and correlation with appropriate treatment options is necessary.

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.

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.

Diagnostic Accuracy and Adequacy of Computed Tomography Versus Fluoroscopy-Guided Percutaneous Transpedicular Biopsy of Spinal Lesions

Background

Transpedicular biopsy of spinal lesions is imperative for the generation of a definite diagnosis. Thus far, literature comparing the accuracy and adequacy between fluoroscopy-guided and computed tomography (CT)-guided transpedicular biopsy of spinal lesions is scarce. We aim to compare the accuracy and adequacy of samples collected with the two techniques at the largest tertiary hospital in Malaysia.

Materials and methods

A total of 60 patients (37 patients with spinal infection and 23 patients with spinal tumour) underwent percutaneous transpedicular biopsy of spinal lesions from January 2013 to December 2017 at a tertiary centre. Demographic data, biopsy method (fluoroscopy-guided and CT-guided), diagnosis, adequacy, and accuracy of samples obtained were assessed.

Results

Among the 60 samples obtained, only two samples (3.3%) were deemed inadequate. There were 10 biopsy samples (16.7%) that were inaccurate. There was no statistical difference between fluoroscopy-guided and CT-guided transpedicular biopsy in terms of accuracy (p = 0.731) and adequacy (p = 0.492).

Conclusions

Fluoroscopy-guided and CT-guided transpedicular biopsy of spinal lesions offer similar accuracy and adequacy. Fluoroscopy-guided biopsy of the spinal lesion will be an option for spine surgeons when CT-guided biopsy is not available.

Percutaneous spine biopsy under cone beam computed tomography guidance for spondylodiscitis: Time is diagnosis

BACKGROUND AND PURPOSE

Percutaneous spine biopsies for spondylodiscitis have been long discussed due to the low microbiologic yield. This retrospective study evaluated factors of cone beam computed tomography-guided spine biopsies that may affect microbiologic yield.

METHODS

We retrospectively reviewed percutaneous spine biopsies under cone beam computed tomography for spondylodiscitis performed from January 2015-December 2020. Clinical and technical features such as the time from initial symptoms to biopsy, level biopsied, biopsy needle type/gauge, technical approach, radiation dose, technical success and microbiologic yield were recorded. Pre-procedure magnetic resonance imaging findings were also recorded such as the number of vertebral bodies involved, and disc morphology. Univariate logistic regression analysis and Receiver operating characteristic analysis were performed to assess any relationship between relevant factors and positive cultures.

RESULTS

A total of 50 patients underwent cone beam computed tomography-guided biopsies for spondylodiscitis, with resulted positive cultures in 18 patients (36%). The mean time from the initial referral of spinal symptoms to procedure in the positive culture group was the most influential finding for positive cultures (odds ratio 56.3, p < 0.001). Among magnetic resonance imaging findings, thin or degenerated intervertebral disc was a negative factor for positive cultures (odds ratio 0.09, p = 0.006). Univariate analysis showed that percutaneous approach (transpedicular vs posterolateral/interlaminar) needle size (11-13 g vs 16-18G, odds ratio 1.2, p = 0.7) and site of biopsy (disc vs bone vs disc plus endplate) did not significantly affect the microbiologic yield of spine biopsy.

CONCLUSION

Percutaneous cone beam computed tomography-guided biopsy for spondylodiscitis is a reliable and safe technique and its microbiologic yield may increase if biopsy is performed within the acute phase of infection.

Best Practices: CT-Guided Percutaneous Sampling of Vertebral Discitis-Osteomyelitis and Technical Factors Maximizing Biopsy Yield

Vertebral discitis-osteomyelitis is an infection of the intervertebral disk and vertebral bodies that may extend to adjacent paraspinal and epidural soft tissues. Its incidence is increasing, likely because of improved treatments and increased life expectancy for patients with predisposing chronic disease and increased rates of IV drug use and intravascular intervention. Because blood cultures are frequently negative in patients with vertebral discitis-osteomyelitis, biopsy is often indicated to identify a causative microorganism for targeted antimicrobial therapy. The reported yield of CT-guided percutaneous sampling is 31-91%, which is lower than the reported yield of open biopsy of 76-91%. However, the less invasive approach may be favored given its relative safety and low cost. If paravertebral fluid collections are present, CT-guided aspiration should be performed. If aspiration is unsuccessful or no paravertebral fluid collections are present, CT-guided percutaneous biopsy should be performed, considering technical factors (e.g., anatomic approach, needle selection, and needle angulation) that may improve microbiologic yield. Although antimicrobial therapy should be withheld for 1-2 weeks before biopsy if clinically feasible, biopsy may still be performed without stopping antimicrobial therapy if needed. Because of the importance of targeted antimicrobial therapy, repeat biopsy should be considered after 72 hours if initial biopsy does not identify a pathogen.

The Diagnosis and Management of Pediatric Spine Infections

The management of pediatric spine infections requires a multidisciplinary approach that includes orthopedic surgeons, infectious disease specialists, interventional radiologists, and others. The prevalence of the disease has increased in frequency, virulence, and degree of soft tissue involvement over the past several years; there has also been a resurgence of some types of infections, such as tuberculosis, fungal, and viral pathogens. The diagnosis can often be reached with a detailed history, physical examination, laboratory tests, and imaging studies. Pathologies mimicking infection require a more invasive approach for diagnosis, including core or open biopsy. The treatment of discitis, spondylodiscitis, vertebral osteomyelitis, spinal epidural, and intramedullary abscesses in children is at times complex, and although many infections can be treated non-surgically with antibiotic therapy, some more extensive infections require surgical management. A timely diagnosis is important as it allows the initiation of the appropriate antimicrobial therapy and would decrease the complexity of the subsequent surgical intervention.

Does image-guided biopsy of discitis-osteomyelitis provide meaningful information to impact clinical management?

OBJECTIVE

The aims of this study are to assess the diagnostic yield of image-guided biopsy for discitis-osteomyelitis (DO), identify factors associated with biopsy yield (laboratory, pre-defined MRI findings, and biopsy technique), and impact of biopsy on management of patients appropriately selected according to the Infectious Disease Society of America guidelines (IDSA).

MATERIALS AND METHODS

This is a retrospective review of patients who underwent biopsy for suspected DO from 2011 to 2019. Reference standards to establish diagnosis of DO in order were histopathology/microbiology from biopsy or subsequent surgical sampling, positive blood culture or serology, and imaging/clinical follow-up. Laboratory markers, pre-biopsy antibiotics and MRI features, procedural-related variables, and impact of biopsy on management were assessed. Multivariable logistic regression was also performed.

RESULTS

Out of 97 included patients, 78 were diagnosed with DO. Overall sensitivity of biopsy for detecting DO was 41.0% (32/78), including 10 patients with positive histopathology only, 14 with positive biopsy culture only, and 8 with both. Elevated ESR (p < 0.001) and epidural collection on MRI (p = 0.008) were associated with higher biopsy yield (63.6% and 68.6%, respectively) in a multivariable model. Procedural variables were not associated with yield. Biopsy results impacted the management in 19/77 (24.7%) patients, of whom 15/19 (78.9%) had treatment de-escalation and 4/19 (21.0%) had treatment escalation including starting new anti-tuberculous and anti-fungal regimens.

CONCLUSION

Sensitivity of biopsy for detecting DO was 41.0%. When IDSA guidelines are followed, biopsy provided impactful information that changed the management in 24.7% of patients. Evaluation for elevated ESR and epidural collection can help improve yield and patient selection for biopsy.

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.

Time to Reconsider Routine Percutaneous Biopsy in Spondylodiscitis?

Percutaneous image-guided biopsy currently has a central role in the diagnostic work-up of patients with suspected spondylodiscitis. However, on the basis of recent evidence, the value of routine image-guided biopsy in this disease can be challenged. In this article, we discuss this recent evidence and also share a new diagnostic algorithm for spondylodiscitis that was recently introduced at our institution. Thus, we may move from a rather dogmatic approach in which routine image-guided biopsy is performed in any case to a more individualized use of this procedure.

Approach-based techniques of CT-guided percutaneous vertebral biopsy

Magnetic resonance imaging (MRI) plays an important role in the characterization of vertebral lesions. Even if latest improvements in MRI permit to understand and suspect the nature of vertebral lesions and positron emission tomography computed tomography (PET-CT) gives information about lesion metabolism, biopsy is still needed in most cases. CT-guided percutaneous vertebral biopsy is a minimally invasive, safe and accurate procedure for definitive tissue diagnosis of a vertebral lesion. CT-guided vertebral biopsy is often the best alternative to a surgical biopsy. The purpose of this technical note is to discuss the approach-based techniques for CT-guided percutaneous vertebral biopsy.

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.

Microbiological diagnosis of suspected vertebral osteomyelitis with a focus on the yield of percutaneous needle biopsy: a 10-year cohort study

This study aims to evaluate in patients hospitalized for vertebral osteomyelitis (VO) the effectiveness of bacteriological diagnosis and the yield of percutaneous needle biopsy (PNB) and to identify factors associated with the result of PNB. This retrospective, two-centre study was conducted between 2000 and 2009. Data on patients with VO were retrieved from the diagnosis database and confirmed by checking medical records. A total of 300 patients with VO were identified; 31 received antibiotics without bacteriological diagnosis, and 269 patients with spondylodiscitis imaging were included. Eighty-three (30.9%) and 18 (6.7%) infections were documented by blood cultures and by bacteriological samples other than PNB, respectively; 168 patients with no bacteriological diagnosis had PNB. Of these, 92 (54.8%) were positive and identified the pathogen and 76 (45.2%) were negative. The most common bacteria were Staphylococcus aureus (34.3%), Streptococcus spp. (20.6%) and coagulase-negative staphylococcus (14.8%). After multivariate analysis, the only factor associated with negative PNB was previous antibiotic intake (OR: 2.31 [1.07-5.00]). When VO was suspected on imaging, bacteriological investigation identified the microorganism in 209/300 (70%) of the cases. The yield of PNB was 54.8%. The only predictor of PNB negativity was previous antibiotic intake. Therefore, we believe that a second PNB should be done after a sufficient delay withdrawal of antibiotics if the first sample was negative. The study was retrospectively registered by the local ethics committee (N°E2019-61).

Complete spinal cord injury following computed tomography-guided biopsy of the thoracic spine: A case report

Computed tomography–guided spine biopsy is a routine procedure in diagnosing vertebral infection or tumor. Following a thoracic intervertebral disc biopsy for presumed osteodiscitis, a patient immediately presented with flaccid paralysis and loss of temperature and pinprick sensation below biopsy level, followed rapidly by complete sensation loss. There was no evidence of direct injury during the biopsy, and emergent post-biopsy magnetic resonance imaging revealed no cord signal abnormality or compression. Later magnetic resonance imaging demonstrated corresponding-level cord edema, presumed secondary to transient cord ischemia during the procedures. Despite frequent utility, authors recommend caution in utilization of computed tomography–guided spine biopsy.

Paediatric spondylodiscitis: a 10-year single institution experience in management and clinical outcomes

PURPOSE

Discitis in the paediatric population poses diagnostic challenges due to non-specific presenting symptoms and difficulty with expressing pain in non-communicating children. Discitis remains a relatively rare condition in the paediatric population and previous reports are limited to small cohorts. In this article, we report our experience in management of discitis over a 10-year period and review the literature on this topic.

METHODS

We retrospectively reviewed cases of paediatric discitis/spondylodiscitis over a 10-year period between 2008 and 2018 managed in our regional paediatric neurosurgery unit. Relevant demographic information, microbiological data, blood investigation profile, antibiotic treatment duration and clinical outcomes were interrogated from clinical notes and electronic databases and further analysed.

RESULTS

Overall, 21 cases of paediatric discitis were identified from year 2008 to 2018 with a female to male ratio of 1.3:1. The mean age at presentation was 4.3 years (range 1 to 15 years). Overall, there were 19 cases of lumbosacral/lumbar, 1 thoracic and 1 cervical discitis. The mean duration of follow-up was 20 months (range 6 to 69 months). The most common presenting features were back pain and refusal to walk/sit or weight bear. Erythrocyte sedimentation rate (ESR) was found to be more sensitive than C-reactive protein (CRP) (sensitivity 78% versus 38%) in our cohort. Computer tomography (CT)-guided biopsy was performed in five cases and only one of these was positive (20%). All patients were treated with intravenous antibiotics with resolution of discitis.

CONCLUSIONS

Presentation of discitis in children can be non-specific and requires high index of suspicion. CT-guided biopsy in our cohort revealed a low rate of positive cultures. Despite negative blood cultures and CT-guided biopsy results, empirical intravenous antibiotics were effective in treating discitis successfully. In our cohort, low yield of CT-guided biopsy does not support its use on each case and this may be reserved for cases resistant to antimicrobial therapy or concerns regarding other pathology mimicking infection. Better understanding and awareness of this condition and its pathophysiology can lead to timely imaging, diagnosis and treatment.

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.

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

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

Intra-discal drain insertion for culture and drainage of pyogenic spondylodiscitis: A one-step diagnostic and therapeutic procedure

BACKGROUND

Pyogenic spondylodiscitis is diagnosed in recent years at higher rates due to the aging population, increased survival of chronic and immune suppressed patients, and the higher rate of invasive procedures leading to bacterial seeding or direct contamination of the disc space. Treatment guidelines encourage bacterial sampling before initiation of antibiotic therapy, and drainage of pus collections. We present our experience with percutaneous CT-guided drain insertion into the disc space itself as a one-step procedure for both culturing and subsequent continuous drainage of the infected disc space.

MATERIALS AND METHODS

We retrospectively reviewed all cases of pyogenic spondylodiscitis admitted to our spine surgery unit during the past five years and treated with CT-guided percutaneous drain insertion into the infected disc space. All patients were followed until complete resolution of the infection.

RESULTS

We retrieved electronic records of 12 patients, none presenting with neurological compression symptoms. Cultures taken at the time of drain insertion were positive in 10 patients (83.3%), much higher than the reported yield for needle aspiration (14-48%) and comparable to the yield of open biopsy. In all patients complete resolution of the infection was reached, determined by clinical, laboratory, and imaging parameters.

CONCLUSIONS

Our retrospective case series demonstrates the feasibility and effectiveness of intra-discal CT-guided drainage of an infected disc space. The procedure does not add much burden to current practice as disc-space sampling for culture is commonly performed anyway, and adds the benefit of direct drainage of the pus at its source.

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.