Diagnostic yield of fluoroscopy-guided biopsy for infectious spondylitis

Comparative analysis of different treatment strategies for septic spondylitis: a retrospective study of one hundred and twelve patients

PURPOSE

To compare the clinical efficacy and prognosis differences between conservative treatment and surgical treatment in patients with non-serious neurologically intact pyogenic spondylitis (Nsi-Nsni-PS), and to provide theoretical reference for the clinical treatment of Nsi-Nsni-PS patients.

METHODS

A retrospective analysis was conducted on 112 cases of Nsi-Nsni-PS patients treated in our hospital from June 2016 to June 2021. According to different treatment methods, they were divided into conservative treatment group (53 cases) and surgical treatment group (59 cases). The general data, laboratory tests, imaging examinations, length of hospital stay, duration of antibiotic use, VAS for pain before and after treatment, ODI, local kyphotic angle correction of diseased vertebrae, and recurrence rate were collected and analyzed in both groups. SPSS 26.0 statistical software was used for analysis. Measurement data were expressed as mean ± standard deviation, and independent sample t-test or rank sum test was used for comparison between groups, while variance analysis was used for intra-group comparison. Count data were expressed as number (%) and compared between groups using chi-square test or Fisher's exact test. Mann-Whitney U test was used to evaluate the changes in local kyphotic angle between the two groups. A p value < 0.05 was considered statistically significant.

RESULTS

There were no significant differences in general data and imaging characteristics between the two groups (P > 0.05); there were no statistically significant differences in the positive culture rate of pathogens, length of hospital stay, duration of antibiotic use, treatment complications, WBC, CRP, ESR levels at admission and discharge, VAS and ODI at admission and last follow-up between the two groups (P > 0.05). The WBC and CRP levels of patients in the conservative group at discharge were lower than those in the surgical group (P < 0.05), and there was no significant difference in the decrease in inflammatory indicators (WBC, CRP, ESR) between the two groups (P > 0.05). By the last follow-up, the neurological function of patients in both groups had significantly improved compared to admission (P < 0.05), with 12 out of 15 ASIA grade D patients in the conservative group recovering to grade E, and 21 out of 25 grade D patients in the surgical group recovering to grade E, with no worsening of neurological function in either group. The differences in VAS and ODI scores at the last follow-up compared to before treatment were statistically significant in both groups (P < 0.05), and all patients regained normal activity. Compared with before treatment, the correction degree of local kyphotic angle in the surgical group at the last follow-up was 0.93 ± 4.94°, slightly higher than that in the conservative group (-0.83 ± 3.37°), and the difference was statistically significant(P < 0.05).

CONCLUSIONS

During our follow-up, we found that both conservative and surgical treatments achieved satisfactory clinical outcomes in patients with Nsi-Nsni-PS. Compared to conservative treatment, surgical intervention did not demonstrate significant advantages in reducing hospitalization time and antibiotic usage duration, increasing pathogen culture positivity rate, lowering treatment complications, or controlling recurrence. However, surgical intervention showed superiority in correcting the local kyphotic angle of spinal lesions, albeit with relatively increased surgical trauma, risks, and treatment costs. At the last follow-up, the surgical group did not exhibit better long-term efficacy. Therefore, when formulating clinical treatment strategies for patients with Nsi-Nsni-PS, it may be preferable to prioritize conservative treatment, supplemented by the use of sensitive or empiric antibiotics for infection management, to improve patient prognosis.

Diagnostic performance of metagenomic next-generation sequencing and conventional microbial culture for spinal infection: a retrospective comparative study

PURPOSE

The study evaluated the diagnostic performance of metagenomic next-generation sequencing (mNGS) as a diagnostic test for biopsy samples from patients with suspected spinal infection (SI) and compared the diagnostic performance of mNGS with that of microbial culture.

METHODS

All patients diagnosed with clinical suspicion of SI were enrolled, and data were collected through a retrospective chart review of patient records. Biopsy specimens obtained from each patient were tested via mNGS and microbial culture. Samples were enriched for microbial DNA using the universal DNA extraction kit, whole-genome amplified, and sequenced using MGISEQ-200 instrument. After Low-quality reads removed, the remaining sequences for microbial content were analyzed and aligned using SNAP and kraken2 tools.

RESULTS

A total of 39 patients (19 men and 20 women) were deemed suitable for enrollment. The detection rate for pathogens of mNGS was 71.8% (28/39), which was significantly higher than that of microbial culture (23.1%, p = 0.016). Mycobacterium tuberculosis complex was the most frequently isolated. Using pathologic test as the standard reference for SI, thirty-one cases were classified as infected, and eight cases were considered aseptic. The sensitivity and specificity values for detecting pathogens with mNGS were 87.1% and 87.5%, while these rates were 25.8% and 87.5% with conventional culture. mNGS was able to detect 88.9% (8/9) of pathogens identified by conventional culture, with a genus-level sensitivity of 100% (8/8) and a species-level sensitivity of 87.5% (7/8).

CONCLUSION

The present work suggests that mNGS might be superior to microbial culture for detecting SI pathogens.

Pathogen detection in suspected spinal infection: metagenomic next-generation sequencing versus culture

PURPOSE

The aim is to compare the pathogen detection performance of metagenomic next-generation sequencing (mNGS) and the culturing of percutaneous needle biopsy samples obtained from an individual with a suspected spinal infection.

METHODS

A retrospective study of 141 individuals with a suspected spinal infection was conducted, and mNGS was performed. The microbial spectra and detection performance between mNGS and the culturing-based method were compared, and the effects of antibiotic intervention and biopsy on the detection performance were assessed.

RESULTS

The microorganisms isolated most commonly via the culturing-based method were Mycobacterium tuberculosis (n = 21), followed by Staphylococcus epidermidis (n = 13). The most common microorganisms detected via mNGS were Mycobacterium tuberculosis complex (MTBC) (n = 39), followed by Staphylococcus aureus (n = 15). The difference in the type of detected microorganisms between culturing and mNGS was observed only in Mycobacterium (P = 0.001). mNGS helped identify potential pathogens in 80.9% of cases, which was significantly higher than the positivity rate of 59.6% observed for the culturing-based method (P < 0.001). Moreover, mNGS had a sensitivity of 85.7% (95% CI, 78.4% to 91.3%), a specificity of 86.7% (95% CI, 59.5% to 98.3%), and sensitivity gains of 35% (85.7% vs. 50.8%; P < 0.001) during culturing, while no differences were observed in the specificity (86.7% vs. 93.3%; P = 0.543). In addition, antibiotic interventions significantly lowered the positivity rate of the culturing-based method (66.0% vs. 45.5%, P = 0.021) but had no effects on the results of mNGS (82.5% vs. 77.3%, P = 0.467).

CONCLUSION

The use of mNGS could result in a higher detection rate compared to that observed with the culturing-based method in an individual with spinal infection and is particularly valuable for evaluating the effects of a mycobacterial infection or previous antibiotic intervention.

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.

Fluoroscopy-Guided Percutaneous Transpedicular Biopsy Versus Posterolateral Endoscopy for Infective Spondylodiskitis Diagnosis: A Comparative Study

OBJECTIVE

We sought to determine the concordance in frequency of microbiologic isolation and species identification in specimens obtained by 2 methods.

METHODS

Intervertebral disk specimens were taken simultaneously from each patient using percutaneous needle and posterolateral endoscopic biopsies. The isolates were reported in frequencies and concordance using the chi square and Cohen kappa tests.

RESULTS

Thirty patients were recruited. The average age was 58.1 years, and 15 patients were women. The clinical evolution time was 7 ± 4 months. The causative organism was identified in 12 (40%) specimens obtained by fluoroscopy-guided percutaneous transpedicular biopsy and in 14 (46.6%) obtained by posterolateral endoscopy. The most common organism isolated was Staphylococcus aureus in 3 patients with the percutaneous technique and in 5 with the endoscopic one; Escherichia coli was isolated in 3 patients with each method. The kappa test showed a high degree of agreement between both methods (kappa = 0.86); the agreement in bacterial species identification was 100%.

CONCLUSIONS

Fluoroscopy-guided percutaneous biopsy and endoscopic sampling have a good degree of concordance for both, frequency of organism isolation and identification in patients with infectious spondylodiskitis.

Factors Impacting the Yield of Image-Guided Biopsy in Native Vertebral Osteomyelitis: A 10-Year Retrospective Study

Background

Image-guided biopsies in patients with suspected native vertebral osteomyelitis (NVO) are recommended to establish the microbiological diagnosis and guide antibiotic therapy. Despite recent advances, the microbiological yield of this procedure remains between 48% and 52%. A better understanding of factors associated with this low yield may lead to improved microbiological diagnosis.

Methods

We retrospectively identified patients with suspected NVO undergoing image-guided biopsies from January 2011 to June 2021 at our institution. Two hundred nine patients undergoing 248 percutaneous biopsies were included. Demographic data, biopsy and microbiologic techniques, clinical characteristics, and antibiotic use were collected. Multivariable logistic regression analysis was conducted to determine factors associated with microbiological yield.

Results

A total of 110 of 209 (52.6%) initial image-guided biopsies revealed positive microbiological results. This number increased to 121 of 209 (57.9%) when repeat image-guided biopsies were included. In multivariable analysis, aspiration of fluid was associated with a 3-fold increased odds of yielding a positive result (odds ratio [OR], 3.13; 95% confidence interval [CI], 1.39-7.04; P = .006), whereas prior antibiotic use was associated with a 3-fold decreased yield (OR, 0.32; 95% CI, .16-.65; P = .002). A univariate subgroup analysis revealed a significant association between the length of the antibiotic-free period and microbiological yield, with the lowest rates of pathogen detection at 0-3 days and higher rates as duration increased (P = .017).

Conclusions

Prior antibiotic use in patients with suspected NVO was associated with a decrease in the microbiological yield of image-guided biopsies. An antibiotic-free period of at least 4 days is suggested to maximize yield. Successful fluid aspiration during the procedure also increases microbiological yield.

Percutaneous Transforaminal Endoscopic Debridement and Drainage with Accurate Pathogen Detection for Infectious Spondylitis of the Thoracolumbar and Lumbar Spine

OBJECTIVE

In this study, we aimed to analyze the clinical outcomes of percutaneous transforaminal endoscopic debridement and drainage (PTEDD) with accurate pathogen detection for patients with infectious spondylitis of the thoracolumbar and lumbar spines.

METHODS

From January 2017 to February 2019, a consecutive series of 43 patients with infectious spondylitis of the thoracolumbar and lumbar spine were surgically treated with PTEDD. Organism culture, next-generation DNA sequencing, and pathological examination of the sample extracted from the infectious site were performed for accurate microbiological diagnosis. All patients were followed up for 24-36 months. Clinical and radiological outcomes were analyzed preoperatively and postoperatively.

RESULTS

Surgeries were completed successfully on all 43 patients under local infiltration anesthesia. Positive culture of the responsible organism was obtained in 33 cases (76.7%). Among the 43 patients who underwent next-generation DNA sequencing, 42 (97.7%) had positive results. Corresponding antibiotic medication was given based on the pathogen detection. The modified Macnab criteria were found to be excellent in 32 patients (74.4%) and good in 11 (25.6%). Postoperative magnetic resonance imaging showed that the abscess and infectious area were reduced significantly at 3 months and had disappeared or almost disappeared at the final follow-up. Spontaneous fusion was obtained in 30 patients (69.8%). No patients required revision or conversion to open debridement and reconstruction.

CONCLUSIONS

For patients with infectious spondylitis of the thoracolumbar and lumbar spine, PTEDD is an effective and safe treatment. Next-generation DNA sequencing is a much more sensitive method for detecting the responsible organisms.

Diagnosis of vertebral osteomyelitis

Native vertebral osteomyelitis (NVO) is a potentially fatal infection which has seen a gradual increase in its incidence over the past decades. The infection is insidious, presenting with symptoms of back pain. Fever is present in about 60 % of patients. Prompt diagnosis of NVO is important to prevent the development of complications. Numerous laboratory and imaging tools can be deployed to accurately establish the diagnosis. Imaging techniques such as magnetic resonance, nuclear imaging, and computed tomography are essential in diagnosing NVO but can also be useful in image-guided biopsies. Laboratory tools include routine blood tests, inflammatory markers, and routine culture techniques of aspirated specimens. Recent advances in molecular techniques can assist in identifying offending pathogen(s). In this review, we detail the arsenal of techniques that can be utilized to reach a diagnosis of NVO.

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.

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.

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).

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.

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.

[Analysis of influencing factors for pathogen culture result in patients with pyogenic spondylitis]

OBJECTIVE

To investigate the effect of clinical factors on the pathogen culture results in the patients with pyogenic spondylitis, and to find out clinical controllable factors which could increase the positive rate of the pathogen culture.

METHODS

A retrospective study reviewed 40 patients who were diagnosed with pyogenic spondylitis in Peking University First Hospital from January 2011 to July 2017. The patients were divided into two groups depending on the culture results, culture negative or culture positive. The influence of clinical uncontrollable factors [the patient's age, gender, predisposing factors, infection site except spine, visual analogue score (VAS), course of disease, spinal segment, white blood cell (WBC), (neutrophilic granulocyte)% (NE%), the incidence of systemic inflammatory response syndrome (SIRS), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), the incidence of paravertebral abscess] and controllable factors (prior antibiotics exposure within 2 weeks, tissue homogenate, surgical approach) on pathogen culture results were analyzed.

RESULTS

Of the 40 patients, 18 patients were female and 22 patients were male. Causative germ was identified in 24/40 patients (60.00%) and dominant by gram positive cocci (68.00%). For clinical uncontrollable factors, there was no significant difference between the two groups in the patient's age, gender, predisposing factors, infection site except spine, VAS, course of disease, spinal segment, WBC, NE% and the incidence of SIRS. ESR [(94.38±6.91) mm/h, P=0.023)], CRP [(64.74±13.51) mg/L, P=0.040], and the incidence of paravertebral abscess (75%, P=0.018) in culture negative group were lower in contrast to culture positive group. For clinical controllable factors, prior antibiotics exposure within 2 weeks (P=0.058, OR=4.030, 95%CI: 0.956-16.993) and tissue homogenate (P=0.014, OR=0.171, 95%CI: 0.042-0.695) were significantly associated with the pathogen culture result. Surgical approach was not significantly associated with pathogen culture result.

CONCLUSION

Patients with high level of ESR, CRP, and paravertebral abscess, would have high positive rate of pathogenic culture. Prior antibiotics exposure was associated with lower positive pathogen culture rate. Culture with tissue homogenate was more likely to find the causative germ, especially for patients without paravertebral abscess who had low level of ESR, CRP and prior antibiotics exposure.

Full Endoscopic Discectomy, Debridement, and Drainage for High-Risk Patients with Spondylodiscitis

OBJECTIVE

To evaluate the efficacy and clinical results of full endoscopic debridement and drainage (FEDD) for high-risk patients with spondylodiscitis.

METHODS

Fourteen patients who underwent FEDD at our institution between November 2015 and September 2017 were retrospectively reviewed. All patients had single-level infectious spondylodiscitis and were high-risk candidates for surgery. Their general condition was evaluated according to the American Society of Anesthesiologists grading system. The Charlson Comorbidity Index was used for comprehensive assessment of comorbidity status. Outcomes were evaluated by numeric rating scale (NRS) pain score, Oswestry Disability Index, modified Macnab criteria, and radiographic images at follow-up.

RESULTS

All 14 patients experienced immediate relief of back pain after FEDD, with no procedure-related complications. The causative bacteria were identified in 10 of the 14 patients (71.5%). Half of the 14 patients had an American Society of Anesthesiologists score of ≥3. The average Charlson Comorbidity Index was 5.1 ± 1.6 points. Compared with the preoperative NRS score of 8.2 ± 0.9, the NRS scores at 1 week and 12 months after surgery were 3.4 ± 1.1 and 1.4 ± 1.2, respectively. A significant improvement in Oswestry Disability Index was observed after surgery (preoperative, 30.1 ± 3.9; 12 months postoperatively, 17.6 ± 6.2; P < 0.05). Satisfaction rate was 85.7% based on the Macnab criteria (excellent or good outcome). None of the patients developed any significant kyphotic deformity after FEDD.

CONCLUSIONS

FEDD may be an effective alternative to extensive open surgery in patients with infectious spondylodiscitis, especially those who are high-risk candidates for surgery (elderly patients with multiple comorbidities and patients in poor general condition).

Diagnostic yield of repeat CT-guided biopsy for suspected infectious spondylodiscitis

OBJECTIVE

The purpose of this study was to examine the yield of repeat CT-guided biopsy in patients with suspected infectious spondylodiscitis following an initial biopsy with negative microbiology, and to identify factors associated with successful pathogen isolation.

MATERIALS AND METHODS

In this retrospective study, 21 patients (12 men, 9 women; mean age, 52, range, 12-84) were identified with clinically and radiologically suspected infectious spondylodiscitis who underwent repeat biopsy following negative cultures from an initial biopsy. The microbe yield as well as demographic, clinical, and laboratory findings were reviewed and statistical analysis was performed.

RESULTS

Repeat CT-guided biopsy isolated a causative microbe in 3/21 patients (14.3%). Younger age (p = 0.021) was significantly associated with successful microbe isolation. All three cases of successful microbe isolation occurred in patients not exposed to antibiotics (3/9 patients) whereas no successful microbe isolation occurred in patients who received antibiotics (0/12 patients); however, this difference did not reach statistical significance (p = 0.062). Gender, duration of symptoms, white blood cell count, biopsy interval, and biopsy site were not significantly associated with microbe isolation.

CONCLUSIONS

Overall microbiologic yield of repeat CT-guided biopsy for patients with suspected infectious spondylodiscitis was low at 14.3%; however, a higher yield was identified in patients who were younger in age and not exposed to pre-biopsy antibiotics.

Culture yield of repeat percutaneous image-guided biopsy after a negative initial biopsy in suspected spondylodiscitis: a systematic review

OBJECTIVE

To systematically review the published data on the culture yield of a repeat (second) percutaneous image-guided biopsy after negative initial biopsy in suspected spondylodiscitis.

MATERIALS AND METHODS

A systematic search was performed of the PubMed/Medline and Embase databases. The methodological quality of the studies included was assessed. The proportions of positive cultures among all initial biopsies and second biopsies (after a negative initial biopsy) were calculated for each study and assessed for heterogeneity (defined as I² > 50%).

RESULTS

Eight studies, comprising a total of 107 patients who underwent a second percutaneous image-guided biopsy after a culture-negative initial biopsy in suspected spondylodiscitis, were included. All eight studies were at risk of bias and were concerning with regard to applicability, particularly patient selection, flow of patients through the study, and timing of the biopsy. The proportions of positive cultures among all initial biopsies ranged from 10.3 to 52.5%, and were subject to heterogeneity (I² = 73.7%). The proportions of positive cultures among all second biopsies after negative initial biopsy ranged from 0 to 60.0%, and were not subject to heterogeneity (I² = 38.7%).

CONCLUSION

Although a second percutaneous image-guided biopsy may have some value in patients with suspected spondylodiscitis, its exact value remains unclear, given the available poor-quality evidence. Future well-designed studies are needed to determine the role of a second percutaneous image-guided biopsy in this setting. Such studies should clearly describe the spectrum of patients that was selected for a second percutaneous image-guided biopsy, the method of biopsy, and differences compared with the first biopsy, if any.

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.

Pyogenic Vertebral Osteomyelitis: Clinical Features, Diagnosis, and Treatment

Pyogenic vertebral osteomyelitis (PVO) may result in neurological deficits and sequelae, so early diagnosis and appropriate treatment are critical. Many previous studies on PVO exist, but our paper has aimed to comprehensively summarize the clinical aspects of PVO. Through review of the vast literature on the clinical research of PVO an overview of the clinical characteristics, diagnostic methods, treatment and prognosis is provided.

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.

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.

Pathologic approach to spinal cord infections

The pathologic evaluation of spinal cord infections requires comprehensive clinical, radiological, and laboratory correlation, because the histologic findings in acute, chronic, or granulomatous infections rarely provide clues for the specific cause. This brief review focuses on the pathologic mechanisms as well as practical issues in the diagnosis and reporting of infections of the spinal cord. Examples are provided of the common infectious agents and methods for their diagnosis. By necessity, discussion is restricted to the infections of the medulla spinalis proper and its meninges, and not bone or soft tissue infections.

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.

Torsional dynamics of steerable needles: modeling and fluoroscopic guidance

Needle insertions underlie a diversity of medical interventions. Steerable needles provide a means by which to enhance existing needle-based interventions and facilitate new ones. Tip-steerable needles follow a curved path and can be steered by twisting the needle base during insertion, but this twisting excites torsional dynamics that introduce a discrepancy between the base and tip twist angles. Here, we model the torsional dynamics of a flexible rod-such as a tip-steerable needle-during subsurface insertion and develop a new controller based on the model. The torsional model incorporates time-varying mode shapes to capture the changing boundary conditions inherent during insertion. Numerical simulations and physical experiments using two distinct setups-stereo camera feedback in semitransparent artificial tissue and feedback control with real-time X-ray imaging in optically opaque artificial tissue-demonstrate the need to account for torsional dynamics in control of the needle tip.