Outcome of culture-negative pyogenic vertebral osteomyelitis: Comparison with microbiologically confirmed pyogenic vertebral osteomyelitis

Plasma Microbial Cell-free DNA Next-generation Sequencing Can Be a Useful Diagnostic Tool in Patients With Osteoarticular Infections

Background

Recent advances in shotgun metagenomic sequencing (sMGS) for detecting microbial cell-free DNA (mcfDNA) in peripheral blood have shown promise across various patient populations. This study evaluates the application of sMGS for diagnosing osteoarticular infections (OAIs), a condition with significant diagnostic challenges.

Methods

We conducted a retrospective analysis on 73 patients suspected of OAIs at the Mayo Clinic from 2019 to 2023, incorporating mcfDNA sMGS (Karius test [KT]) into their diagnostic evaluation. We categorized the clinical impact of KT on OAI diagnoses and management into 4 distinct outcomes. (1) KT was able to confirm an established diagnosis, (2) KT supported noninfectious diseases diagnosis, (3) KT established an unsuspected diagnosis, (4) KT did not add relevant information.

Results

In our cohort, KT was performed in 73 patients. Among the infected individuals, KT yielded positive results in 22 of 43 (51.2%) cases. Of these 22 cases, 11 (50%) showed agreement with conventional diagnostic workup, whereas in 5 (22.7%) cases, the KT established an unsuspected diagnosis. Native vertebral osteomyelitis diagnosis (P < .001) or OAIs with concomitant presence of endocarditis or endovascular infection (P = .005) were statistically associated with a definite, probable, or possible diagnostic certainty of KT result.

Conclusions

In complex OAIs, KT enhanced diagnostic accuracy by 11.6%, proving especially beneficial in diagnosing native vertebral osteomyelitis and infections with concurrent endocarditis or endovascular complications. Our findings underscore the utility of KT in the diagnostic workflow for challenging OAI cases, potentially altering clinical management for a significant subset of patients.

Culture-negative versus culture-positive in pyogenic spondylitis and analysis of risk factors for relapse

OBJECTIVES

This study aims to compare and analyze the clinical features, diagnosis, treatment and prognosis of culture-negative and culture-positive primary pyogenic spondylitis.

METHODS

In a retrospective analysis, 202 cases of adult primary pyogenic spondylitis with complete clinical data in our hospital from January 2013 to January 2020 were divided into two groups according to bacterial culture results: culture negative (n = 126) and culture positive (n = 76). We compare the clinical characteristics, diagnosis, treatment and prognosis of patients with different culture results.

RESULTS

The culture positive rate was 37.62% (76/202). There were no significant differences in age, gender, affected segment, spinal abscess, diabetes mellitus, course of disease, surgery, recurrence, and follow-up time between the two groups (p>.05). There were statistically significant differences in hospital admission erythrocyte sedimentation rate (ESR), admission C-reactive protein (CRP), admission white blood cell (WBC) count, discharge ESR, discharge CRP, ESR decline rate, CRP (p<.05). There were statistically significant differences in the rate of decline, hospitalization days, and body temperature ≥38 °C (p<.05). Higher CRP levels on admission, antibiotic treatment time <6 weeks, and body temperature ≥ 38 °C are independent risk factors for infection recurrence.

CONCLUSIONS

The culture-negative group's admission WBC, admission ESR, admission CRP, discharge ESR, discharge CRP, ESR decline rate, CRP decline rate, and hospital stay were lower than the culture positive group, the difference was statistically significant (p<.05). The independent risk factors for infection recurrence are higher CRP levels in hospital admission, antibiotic treatment time <6 weeks, and body temperature ≥ 38 °C.

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

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

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

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

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

Assessment of Therapeutic Responses Using a Deep Neural Network Based on 18F-FDG PET and Blood Inflammatory Markers in Pyogenic Vertebral Osteomyelitis

Background and Objectives: This study investigated the usefulness of deep neural network (DNN) models based on ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) and blood inflammatory markers to assess the therapeutic response in pyogenic vertebral osteomyelitis (PVO). Materials and Methods: This was a retrospective study with prospectively collected data. Seventy-four patients diagnosed with PVO underwent clinical assessment for therapeutic responses based on clinical features during antibiotic therapy. The decisions of the clinical assessment were confirmed as ‘Cured’ or ‘Non-cured’. FDG-PETs were conducted concomitantly regardless of the decision at each clinical assessment. We developed DNN models depending on the use of attributes, including C-reactive protein (CRP), erythrocyte sedimentation ratio (ESR), and maximum standardized FDG uptake values of PVO lesions (SUV_max), and we compared their performances to predict PVO remission. Results: The 126 decisions (80 ‘Cured’ and 46 ‘Non-cured’ patients) were randomly assigned with training and test sets (7:3). We trained DNN models using a training set and evaluated their performances for a test set. DNN model 1 had an accuracy of 76.3% and an area under the receiver operating characteristic curve (AUC) of 0.768 [95% confidence interval, 0.625–0.910] using CRP and ESR, and these values were 79% and 0.804 [0.674–0.933] for DNN model 2 using ESR and SUV_max, 86.8% and 0.851 [0.726–0.976] for DNN model 3 using CRP and SUV_max, and 89.5% and 0.902 [0.804–0.999] for DNN model 4 using ESR, CRP, and SUV_max, respectively. Conclusions: The DNN models using SUV_max showed better performances when predicting the remission of PVO compared to CRP and ESR. The best performance was obtained in the DNN model using all attributes, including CRP, ESR, and SUV_max, which may be helpful for predicting the accurate remission of PVO.

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.

Treatment Guideline for Patients with Native Culture-negative Pyogenic Vertebral Osteomyelitis

BACKGROUND

With the development of evidence-based guidelines for the diagnosis and antibiotic treatment of patients with pyogenic vertebral osteomyelitis, various nonsurgical and surgical treatment strategies have achieved favorable results. However, sufficient administration of appropriate antibiotics is a prerequisite for treatment success, which cannot be guaranteed in patients with culture-negative pyogenic vertebral osteomyelitis. Unfortunately, previous studies on culture-negative pyogenic vertebral osteomyelitis were limited by small patient groups, short follow-up periods, varied treatment protocols, and inconsistently defined clinical endpoints.

QUESTIONS/PURPOSES

Among patients treated according to our center's treatment protocol for culture-negative pyogenic vertebral osteomyelitis, which included patients treated without surgery, with surgery but without spinal instrumentation, as well as patients treated with instrumented surgery, (1) what proportion of patients in each treatment group experienced recurrence (or persistence) of infection, complications of treatment, and death; and (2) what factors were independently associated with recurrent or persistent infection after treatment under this algorithm?

METHODS

This was a retrospective evaluation of a treatment protocol in use at one center from 2008 to 2020. During that time, we treated 183 patients for culture-negative pyogenic vertebral osteomyelitis. The diagnosis was based on clinical, laboratory, and radiological features excluding disease that presents similar features to pyogenic vertebral osteomyelitis. For those patients, our protocol included three possible approaches: nonsurgical treatment, including the use of empirical antibiotics (nonoperative group, n = 82); spinal decompression without instrumentation (noninstrumented group, n = 41); and spinal decompression with instrumentation (instrumented group, n = 60). The indications for each treatment during the period remained relatively consistent. Nonsurgical treatment including empirical antibiotics was applied to all patients according to the specified antibiotic protocol. Spinal decompression without instrumentation was employed when a patient presented substantial or aggravating neurologic deficits or intractable pain from an abscess. Instrumentation was added in patients with mechanical instability before or after spinal decompression. Minimum follow-up to be included in this study was 1 year, and 91% (252 of 277) of patients were accounted for at that time, with no differential loss to follow-up among the study groups (12, five, and four patients missing from the three groups, respectively, at 1 year). Chart review was performed to ascertain the proportion of patients in each group who experienced recurrence, complications, and death. Factors associated with recurrence were assessed across the entire cohort using a multivariable logistic model. We analyzed 1-year recurrence and mortality rates using the Kaplan-Meier method, and their 95% confidence intervals were calculated using the method by Hosmer and Lemeshow.

RESULTS

At 1 year, the recurrence-free survival rate was 87% (95% confidence interval 78% to 93%) in the nonoperative group, 87% (95% CI 72% to 94%) in the noninstrumented group, and 91% (95% CI 80% to 96%) in the instrumented group. The proportion of patients who experienced a major medical complication in each group was 12% (10 of 82), 10% (4 of 41), and 8% (5 of 60), respectively. At 1 year, the survival rate with patient death as the endpoint was 95% (95% CI 88% to 98%) in the nonoperative group, 95% (95% CI 82% to 99%) in the noninstrumented group, and 97% (95% CI 87% to 99%) in the instrumented group. After controlling for potentially confounding variables including age, medical comorbidities, and anatomical involvement of infection, the following factors were independently associated with increased odds of infection recurrence or persistence: higher Charlson Comorbidity Index (CCI) score (odds ratio 1.6 per point on the CCI [95% CI 1.2 to 2.1]; p = 0.004) and the presence of a psoas abscess (OR 4.7 [95% CI 1.6 to 13.9]; p = 0.005).

CONCLUSION

Among patients with negative initial nonoperative culture results, spinal decompression and abscess drainage can be used in those with substantial or aggravating neurological deficits or intractable pain caused by an abscess, while additional early spinal instrumentation can be applied upon consideration of their medical comorbidities and the presence of a psoas abscess when mechanical instability is present before or after the spinal decompression. Reasonable clinical results can be expected, regardless of the results from subsequent operative cultures. However, our study results should be replicated by other centers, and further studies that consider individual differences such as bone mineral density and include patients with previous spinal instrumentation or recurrent infection should be performed to establish a more comprehensive treatment protocol.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Risk factors of multidrug-resistant pyogenic spondylitis in thoraco-lumbar spine: A retrospective study of 122 cases

BACKGROUND

The number of spinal infections has been increasing in developed countries due to the increase of aged or immunosuppressed patients. Spondylitis caused by multidrug-resistant (MDR) bacterial infection often become intractable and require long-term antibiotic therapy and multiple surgeries. Therefore, it is of great importance to understand risk factors for MDR spinal infections. The aim of this study was to elucidate the risk factors for MDR bacterial spondylitis.

METHODS

A total of 122 patients (82 men, 40 women; average age: 63.8 y) with thoracic/lumbar spondylitis who underwent posterolateral full-endoscopic debridement and irrigation were included. The organisms detected by this endoscopic procedure were investigated, and the incidence and risk factors for MDR bacterial infection were retrospectively analyzed.

RESULTS

Cultures of specimens obtained by endoscopic procedures were positive in 78 patients (63.9%). Among 68 isolated bacteria, MDR bacteria accounted for 47.1%. Multivariate analysis showed that significant risk factors for MDR bacterial infection included autoimmune connective tissue disease (P = 0.03) and central venous catheter (P = 0.02). The incidence of MDR bacteria in patients who were administered a broad-spectrum antibiotic for more than 1 month preoperatively was 64.0%, which was significantly higher than in patients who were administered a broad-spectrum antibiotic for less than 1 month and patients who were administered a narrow-spectrum antibiotic (P < 0.01, P < 0.01, respectively).

CONCLUSIONS

The significant risk factors for MDR bacterial spondylitis included immunosuppressed conditions, such as autoimmune connective tissue disease, presence of central venous catheter, and longer administration periods of a broad-spectrum antibiotic. In patients with pyogenic spondylitis who could not be controlled with previous antibiotics and whose result of culture was negative, administration of anti-MRSA antibiotics would be considered when they have the risk factors identified in this study.

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.

Validity of Clinical Assessment Using Clinical Symptoms and C-Reactive Protein for Therapeutic Response in Pyogenic Vertebral Osteomyelitis: Analysis Based on 18F-FDG-PET

Backgroundand objectives: The clinical assessment of therapeutic response in pyogenic vertebral osteomyelitis (PVO) has been usually performed based on the changes of clinical symptoms and blood inflammatory markers. Recently, ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET) has emerged as an alternative independent method. We analyzed the validity of the clinical assessment for detecting residual PVO based on ¹⁸F-FDG-PET. Materials and Methods: This study was conducted with 53 patients confirmed as lumbar PVO under retrospective design. All patients underwent clinical assessment using clinical symptoms and C-reactive protein (CRP) for therapeutic response after parenteral antibiotic therapy, which led to the decision of placement in the uncontrolled (group UC) or controlled (group C) group. The validity of clinical assessment was analyzed based on the cut-off values of FDG uptake for detecting residual PVO as references, which are already established in the previous literature. Results: The mean duration of parenteral antibiotic therapy and recurrence rate were 42.19 ± 15.84 (21-89) days and 9.4% (5/53), respectively. ¹⁸F-FDG-PETs were performed at 80 rounds of clinical assessment on 37.40 ± 13.15 (21-83) days of parenteral antibiotic therapy and divided: 31 into group UC and 49 into group C, according to the decisions of clinical assessment. Based on the cut-off values of FDG uptake, clinical assessment showed 48.4-58.1% of false positive for residual PVO in group UC. However, ¹⁸F-FDG-PET showed 8.2% (4/49) of false negative for residual PVO in group C, which led to recurrences. Conclusions: Clinical assessment using clinical symptoms and CRP for evaluating therapeutic response in PVO is still a useful method in terms of similar recurrence rate compared to ¹⁸F-FDG-PET. However, the high rate of false positive for residual PVO can prolong the use of unnecessary antibiotics and overall treatment period.

Neurosurgical Management and Outcome Parameters in 237 Patients with Spondylodiscitis

Surgical treatment of spondylodiscitis allows for rapid mobilization and shortens hospital stays, which makes surgical treatment the first-line therapy. We aim to describe our experiences with operative treatment on spondylodiscitis and to determine the parameters that are important in the prediction of outcomes. A retrospective review identified 237 patients who were operatively treated for spondylodiscitis in our institution between January 2010 and December 2018. Clinical data were collected through review of electronic records and relevant imaging. In all cases, contrast-enhancing MRI from the infected region of the spine was obtained. Leukocyte count and C-reactive protein concentrations (CRP) were determined in all the patients. We included 237 patients in the study, 87 female (36.7%) and 150 male (63.3%), with a mean age of 71.4 years. Mean follow-up was 31.6 months. Forty-five patients had spondylodiscitis of the cervical, 73 of the thoracic, and 119 of the lumbosacral spine. All the patients with spondylodiscitis of the cervical spine received instrumentation. In thoracic and lumbar spine decompression, surgery without instrumentation was performed in 26 patients as immediate surgery and in a further 28 patients in the early stages following admission, while 138 patients received instrumentation. Eighty-nine patients (37.6%) had concomitant infections. Infection healing occurred in 89% of patients. Favorable outcomes were noted in patients without concomitant infections, with a normalized CRP value and in patients who received antibiotic therapy for more than six weeks (p < 0.05). Unfavorable outcomes were noted in patients with high CRP, postoperative spondylodiscitis, and recurrent spondylodiscitis (p < 0.05). Application of antibiotic therapy for more than six weeks and normalized CRP showed a correlation with favorable outcomes, whereas concomitant infections showed a correlation with unfavorable outcomes. A detailed screening for concomitant infectious diseases is recommended.

Clinical and Radiological Features Predicting Intervertebral Autofusion after Successful Antibiotic Therapy in Pyogenic Vertebral Osteomyelitis

Background: Pyogenic vertebral osteomyelitis (PVO) is a bacterial infection involving the intervertebral disc, vertebral body, and paravertebral soft tissues. Damaged intervertebral structure is a major cause of persistent back pain even after successful antibiotic therapy, which can be improved by achieving autofusion or via additional surgical fixation. In this study, we analyzed the clinical and radiological features predicting intervertebral autofusion after successful antibiotic therapy in lumbar PVO. Methods: This study was retrospectively conducted with 32 patients (20 men and 12 women) diagnosed with lumbar PVO that was completely cured with no recurrences after antibiotic therapy. They were divided into two groups with (group A, n = 18) and without (group B, n = 14) intervertebral autofusion at six-month follow-up. Differences in back pain, blood inflammatory markers, and radiological features of PVO on simultaneous ¹⁸F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (¹⁸F-FDG-PET/MRI) of the intervertebral structure between the two groups were analyzed. Results: The mean duration of antibiotic therapy was 41.44 ± 14.21 (21–89) days. Group A showed a statistically higher erythrocyte sedimentation ratio (ESR; 59.28 ± 32.33 vs. 33.93 ± 18.76 mm/h, p = 0.014; normal range of ESR < 25), maximum standardized ¹⁸F-FDG uptake (SUV_max; 5.56 ± 1.86 vs. 3.98 ± 1.40, p = 0.013), and sustained extensive edematous changes on T2-weighted fat saturation (T2FS) MRI (p = 0.015) immediately after successful antibiotic therapy. However, no significant differences were observed in back pain, C-reactive protein, or the distribution of ¹⁸F-FDG uptake/contrast enhancement on ¹⁸F-FDG-PET/MRI (p > 0.05). Conclusions: Higher ESR and SUV_max of the intervertebral structure and sustained extensive edematous change on T2FS MRI immediately after successful antibiotic therapy are related with subsequent intervertebral autofusion, which should be carefully considered when assessing therapeutic response in PVO.

Clinical characteristics of pyogenic vertebral osteomyelitis, and factors associated with inadequate treatment response

OBJECTIVES

Pyogenic vertebral osteomyelitis (PVO) is associated with a high burden of disease. Our study aimed to describe characteristics at presentation of PVO, the risk of inadequate treatment response (ITR), relapse, and death, and to determine risk factors for ITR.

METHODS

Patients with an ICD-10 discharge code for PVO and admission to a major Danish university hospital between November 2016 and April 2019 were included. ITR was defined as clinical, microbiological, and/or radiological progression during treatment. Data were collected through review of medical records, and logistic regression was used to determine adjusted odds ratios (aOR).

RESULTS

Of 106 patients included, 87% presented with pain in the spine, 97% elevated CRP, 14% severe sepsis, and 13% with a history of previous spinal surgery. 39% were infected with Staphylococcus aureus and 9% with Escherichia coli. 31% responded inadequately to treatment, and risk factors for ITR were previous spinal surgery (aOR 19.29; 95% confidence interval (CI) 2.20-169.08), severe sepsis (aOR 4.59; 95% CI 1.28-15.41), and infection with Escherichia coli (aOR 8.10; 95% CI 1.71-38.45). 13% experienced relapse within the first 2 years, while the 1-year crude mortality was 12%.

CONCLUSION

Staphylococcus aureus is still the main pathogen in PVO patients, and the risks of relapse and mortality remain high. Factors found to be associated with ITR were previous spinal surgery, severe sepsis, and infection with Escherichia coli.

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.

Antimicrobial therapy and assessing therapeutic response in culture-negative pyogenic vertebral osteomyelitis: a retrospective comparative study with culture-positive pyogenic vertebral osteomyelitis

Background

There are still controversies regarding the treatment and outcomes in culture-negative pyogenic vertebral osteomyelitis (PVO). The purpose of this study is to investigate the antimicrobial therapy, assessment of therapeutic response, and outcome of culture-negative PVO compared to culture-positive PVO.

Methods

A retrospective study was performed with non-surgical lumbar PVO patients. The patients were divided into two groups based on the causative bacterial identification (CN group with culture-negative PVO and CP group with culture-positive PVO). The clinical features, use of antibiotics, laboratory data, and outcomes were compared between the two groups.

Results

Seventy-three patients with 41 (56.2%) of the CN group and 32 (43.8%) of the CP group were enrolled. The CN group showed a shorter duration of parenteral antibiotics (45.88 ± 16.14 vs. 57.31 ± 24.39, p = 0.019) but a tendency of prolonged duration of total (parenteral + oral) antibiotics (101.17 ± 52.84 vs. 84.19 ± 50.29 days, p = 0.168). When parenteral antibiotics were discontinued or switched to oral antibiotics, the mean erythrocyte segmentation rate (ESR, normal range: < 25 mm/h), C-reactive protein (CRP, normal range: < 0.5 mg/dL) level, and visual analog scale (VAS) score of back pain were 42.86 ± 24.05 mm/h, 0.91 ± 1.18 mg/dL, and 4.05 ± 1.07, respectively, with no significant differences between the two groups. The recurrence rates of CN and CP groups were 7.3% (3/41) and 6.3% (2/32), respectively (p = 1.000). The presence of epidural abscess was the most significant factor for the identification of causative bacteria (p = 0.002), and there was no significant relationship between the use of empirical antibiotics before tissue culture and the causative bacterial identification (p = 0.194).

Conclusions

The CN group required a shorter duration of parenteral antibiotics than the CP group. Discontinuation of parenteral antibiotics or changing the administration route can be considered based on the values of ESR, CRP, and VAS score of back pain. The presence of epidural abscess was the most significant factor for the identification of causative bacteria.

Assessment of Therapeutic Response in Pyogenic Vertebral Osteomyelitis Using 18F-FDG-PET/MRI

Purpose: There is still no definite method to determine therapeutic response in pyogenic vertebral osteomyelitis (PVO). We analyzed the value of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) for assessing therapeutic response in PVO. Methods: This retrospective study included 53 patients (32 men and 21 women) with lumbar PVO. The results of clinical assessments for therapeutic response were divided into “Cured” (group C) and “Non-cured” (group NC). The differences in clinical and radiological features of PVO lesions between the two groups were analyzed using clinical data and simultaneous FDG-PET/magnetic resonance imaging (MRI) obtained at each clinical assessment. Results: Clinical assessments and FDG-PET/MRIs were performed at 41.89 ± 16.08 (21–91) days of parenteral antibiotic therapy. There were 39 patients in group C and 14 in group NC. Diagnostic accuracies (DAs) of FDG uptake intensity-based interpretation and C-reactive protein (CRP) for residual PVO were as follows (p < 0.01): 84.9% of the maximum standardized uptake value of PVO lesion (PvoSUV_max), 86.8% of ΔPvoSUV_max−NmlSUV_max (SUV_max of normal vertebra), 86.8% of ΔPvoSUV_max−NmlSUV_mean (SUV_mean of normal vertebra), and 71.7% of CRP. DAs were better (92.5–94.3%) when applying FDG uptake intensity-based interpretation and CRP together. Under the FDG uptake distribution-based interpretation, FDG uptake was significantly limited to intervertebral structures in group C (p = 0.026). Conclusion: The interpretations of intensity and distribution of FDG uptake on FDG-PET are useful for detecting residual PVO in the assessment of therapeutic response of PVO. The combination of FDG-PET and CRP is expected to increase DA for detecting residual PVO.

Clinical and Radiological Analysis of Pyogenic Vertebral Osteomyelitis Immediately after Successful Antimicrobial Therapy: Considerations for Assessing Therapeutic Response

Purpose: The clinical and radiological abnormal findings continue even after successful treatment in pyogenic vertebral osteomyelitis (PVO). We analyzed the clinical and radiological features of cured PVO based on ¹⁸F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (FDG-PET/MRI) and compared the radiological differences between FDG-PET and MRI for assessing therapeutic response in PVO. Methods: This study included 43 patients (28 men and 15 women) with lumbar PVO who had no recurrence after successful antimicrobial therapy. They were divided into two groups based on the location of maximum standardized FDG uptake value (SUV_max) of PVO lesion on FDG-PET/MRI when parenteral antibiotics were discontinued (31 in group A: Intervertebral structure; 12 in group B: Vertebral body and paravertebral muscle). The differences of clinical symptoms, hematological inflammatory indices, and radiological features were retrospectively analyzed. Results: The patients were treated with 42.28 ± 14.58 (21–89) days of parenteral antibiotics. There were significant differences in C-reactive protein (0.97 ± 1.10 vs. 0.51 ± 0.31 mg/dL, p = 0.041; normal range of CRP < 0.5), back pain (4.29 ± 1.13 vs. 3.50 ± 1.00, p = 0.040; visual analog scale), and SUV_max (4.34 ± 1.24 vs. 5.89 ± 1.57, p < 0.001) between the two groups. In the distribution pattern of PVO lesions, FDG-PET overall showed recovery pattern earlier than MRI did (p < 0.001). Conclusions: In cured PVO, the clinical features vary depending on the location of major structural damage of PVO lesion. The involvement of intervertebral structure is related with sustained back pain and elevation of CRP, and vertebral body/paravertebral muscle shows favorable clinical features despite advanced structural damages.

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.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Conservative Treatment of Spondylodiscitis: Possible Therapeutic Solution in Case of Failure of Standard Therapy

Introduction:

Spondylodiscitis (SD) is an uncommon disease but not rare, because it represents around 3–5% of all cases of osteomyelitis. Late diagnosis and/or inadequate treatment often cause irreversible damage to cause neurological deficit. Most require only conservative treatment, sometimes a surgical approach is required.

Aim:

The purpose of this study is to propose a conservative protocol to treat spondylodiscitis when the standard conservative treatment has failed. This alternative treatment has been for a long time at the Codivilla-Putti Institute.

Methods:

We performed a prospective cohort study of 192 consecutive patients who underwent paravertebral intramuscular injections of antibiotic associated with standard treatment at our Center from January 2010 to December 2015 with SD. Of this 192 patients we selected 98 who had already undergone standard antibiotic therapy at another hospital without resolution of the disease. All patients have performed our protocol that provides a total of 3 cycles, each of 3 weeks, repeated at approximately 5 weeks apart. For each patient we evaluated Erythrocyte Sedimentation Rate (ESR), C-Reactive Protein (CRP), White Blood Cells (WBC) indexes, SF36 and VAS Score at the beginning and at the end of the treatment.

Results:

At a mean follow up of 22 months (range 60-12), clinical healing was achieved in 87 patients (88,9%) of cases with significant reduction in back pain and functional limitation. The VAS Score and the SF36 were better at the end of treatment compared to previous “GOLD STANDARD” treatments in the previous hospitalization in another hospital. In most cases there were slightly reduced in inflammatory indexes.

Conclusion:

There are no studies in the literature demonstrating the effective efficacy of local infiltrative treatment with antibiotics, associated with standard treatment protocol. We believe that our protocol in treating SD, favors an early functional recovery, and be able to offer more chance of success than the standard treatment.

Selection of an appropriate empiric antibiotic regimen in hematogenous vertebral osteomyelitis

Background

Empiric antibiotic therapy for suspected hematogenous vertebral osteomyelitis (HVO) should be initiated immediately in seriously ill patients and may be required in those with negative microbiological results. The aim of this study was to inform the appropriate selection of empiric antibiotic regimens for the treatment of suspected HVO by analyzing antimicrobial susceptibility of isolated bacteria from microbiologically proven HVO.

Method

We conducted a retrospective chart review of adult patients with microbiologically proven HVO in five tertiary-care hospitals over a 7-year period. The appropriateness of empiric antibiotic regimens was assessed based on the antibiotic susceptibility profiles of isolated bacteria.

Results

In total, 358 cases of microbiologically proven HVO were identified. The main causative pathogens identified were methicillin-susceptible Staphylococcus aureus (33.5%), followed by methicillin-resistant S. aureus (MRSA) (24.9%), Enterobacteriaceae (19.3%), and Streptococcus species (11.7%). Extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and anaerobes accounted for only 1.7% and 1.4%, respectively, of the causative pathogens. Overall, 73.5% of isolated pathogens were susceptible to levofloxacin plus rifampicin, 71.2% to levofloxacin plus clindamycin, and 64.5% to amoxicillin-clavulanate plus ciprofloxacin. The susceptibility to these oral combinations was lower in cases of healthcare-associated HVO (52.6%, 49.6%, and 37.6%, respectively) than in cases of community-acquired HVO (85.8%, 84.0%, and 80.4%, respectively). Vancomycin combined with ciprofloxacin, ceftriaxone, ceftazidime, or cefepime was similarly appropriate (susceptibility rates of 93.0%, 94.1%, 95.8%, and 95.8%, respectively).

Conclusions

Based on our susceptibility data, vancomycin combined with a broad-spectrum cephalosporin or fluoroquinolone may be appropriate for empiric treatment of HVO. Fluoroquinolone-based oral combinations may be not appropriate due to frequent resistance to these agents, especially in cases of healthcare-associated HVO.

Insights into complication rates, reoperation rates, and healthcare utilization associated with use of recombinant human bone morphogenetic protein–2 in patients with spine infections

OBJECTIVE

Use of recombinant human bone morphogenetic protein–2 (rhBMP-2) in patients with spine infections is controversial. The purpose of this study was to identify long-term complications, reoperations, and healthcare utilization associated with rhBMP-2 use in patients with spine infections.

METHODS

This retrospective study extracted data using ICD-9/10 and CPT codes from MarketScan (2000–2016). Patients were dichotomized into 2 groups (rhBMP-2, no rhBMP-2) based on whether rhBMP-2 was used during fusion surgery for spinal infections. Outcomes of interest were reoperation rates (index level, other levels), readmission rates, discharge disposition, length of stay, complications, and healthcare resource utilization at the index hospitalization and 1, 3, 6, 12, and 24 months following discharge. Outcomes were compared using nonparametric 2-group tests and generalized linear regression models.

RESULTS

The database search identified 2762 patients with > 24 months’ follow-up; rhBMP-2 was used in 8.4% of their cases. The patients’ median age was 53 years, 52.43% were female, and 15.11% had an Elixhauser Comorbidity Index ≥ 3. Patients in the rhBMP-2 group had higher comorbidity indices, incurred higher costs at index hospitalization, were discharged home in most cases, and had lower complication rates than those in the no–rhBMP-2 group. There was no statistically significant between-groups difference in complication rates 1 month following discharge or in reoperation rates at 3, 6, 12, and 24 months following the procedure. Patients in the no–rhBMP-2 group incurred higher utilization of outpatient services and medication refill costs at 1, 3, 6, 12, and 24 months following surgery.

CONCLUSIONS

In patients undergoing surgery for spine infection, rhBMP-2 use was associated with lower complication rates and higher median payments during index hospitalization compared to cases in which rhBMP-2 was not used. There was no significant between-groups difference in reoperation rates (index and other levels) at 3, 6, 12, and 24 months after the index operation. Patients treated with rhBMP-2 incurred lower utilization of outpatient services and overall payments. These results indicate that rhBMP-2 can be used safely in patients with spine infections with cost-effective utilization of healthcare resources and without an increase in complications or reoperation rates.

Clinical Characteristics and Outcomes of Patients with Culture-Negative Pyogenic Spondylitis according to Empiric Glycopeptide Use

Background

The optimal choice of antibiotics is challenging in culture-negative pyogenic spondylitis (PS). The empiric use of glycopeptides is suggested depending on various risk factors, although clinical data are sparse. This study aimed to analyze the clinical characteristics and outcomes of patients with culture-negative PS and evaluate the effect of empiric glycopeptide use on clinical outcomes in these patients.

Materials and Methods

Data on the characteristics, treatment, and outcomes of 175 patients diagnosed with PS were retrospectively obtained from the electronic database of a tertiary referral hospital from 2009 to 2016. Patients with negative culture results were grouped by the duration of glycopeptide treatment: glycopeptide therapy <28 days (Group A) and glycopeptide therapy ≥28 days (Group B).

Results

Of 89 patients with negative culture results, 78 were included in the analysis (Group A, n = 66; Group B, n = 12). The mean age of patients with negative culture results was 65.5 years, and 52.6% were male. The median follow-up duration was 573 (interquartile range [IQR], 83 – 1,037) days. The duration of intravenous glycopeptide therapy was 0.0 (IQR, 0.0 – 0.0) days and 55.5 (IQR, 37.0 – 75.7) days for Groups A and B, respectively. Patients who used glycopeptide longer empirically (Group B) had more commonly undergone a previous spinal procedure, including surgery (P = 0.024). The length of hospitalization, erythrocyte sedimentation rate, and C-reactive protein level were significantly higher in Group B compared with those in Group A (P <0.001, P <0.001, and P = 0.006, respectively). Regarding treatment modalities, patients in Group B underwent surgery more frequently (P = 0.017). The duration of parenteral antibiotic treatment was longer in Group B (P <0.001). Recurrence was noted in 7 patients (9.0%), and the recurrence rate was not significantly different between the 2 groups (Group A, 5/66 [7.6%]; Group B, 2/12 [16.7%]; P = 0.293).

Conclusion

The recurrence rate among patients with culture-negative PS was not different based on the duration of empiric glycopeptide use. However, considering the small sample size and heterogeneity of our study population, we suggest that it is reasonable to administer glycopeptide antibiotics in these patients depending on clinical risk factors. Further large-scale prospective studies are needed to obtain more evidence for appropriate antibiotic treatment.

Treatment Strategy and Outcomes in Patients with Hematogenous Culture-Negative Pyogenic Vertebral Osteomyelitis

Study Design

Retrospective case series.

Purpose

The aim of this study was to analyze functional and radiological outcomes in patients with culture-negative pyogenic vertebral osteomyelitis (PVO).

Overview of Literature

There were only few literature available for these group of patients.

Methods

Patients with biopsy-positive but culture-negative PVO were included. We analyzed records for data on demography, comorbidities, coexisting infections, neurological status, prior antibiotic therapy, pre- and postoperative erythrocyte sedimentation rate, C-reactive protein levels, and Oswestry Disability Index, and Japanese Orthopedics Association scores.

Results

Sixty-one patients were included, of which data of 45 patients were available for follow-up. The patients were predominantly males (71%), with a mean age of 53.2 years. Seventy-seven percent patients had comorbidities. Echocardiography, blood culture, and urine culture were performed on 8%, 24%, and 18% of patients, respectively. Thirty-one percent patients had neurological deficits. Computed tomography-guided biopsy was performed on 67% patients. Fifty-two percent patients were treated surgically, and 48% were treated non-surgically. Nineteen percent patients were treated according to the results of cultures from other foci, and the rest were treated empirically. For the initial 2 weeks, all patients were treated with intravenous antibiotics empirically or based on culture from other foci. This treatment was followed by 10 weeks of oral cloxacillin/cephalexin for gram-positive organisms or ciprofloxacin for gram-negative organisms. The mean follow-up time was 18 months (range, 12–120 months). All patients had improvement in Japanese Orthopedics Association, Oswestry Disability Index, and Visual Analog Scale scores (p<0.001).

Conclusions

Treatment with empirical antibiotics for 12 weeks with watchful clinical and radiological follow-up yields good resolution of the disease. Further multicenter clinical research needs to be performed for obtaining an algorithmic treatment plan for these patients.

Cervical Spine Osteomyelitis: A Systematic Review of Instrumented Fusion in the Modern Era

OBJECTIVE

For cases of cervical osteomyelitis that require surgery, concern has continued regarding instrumentation owing to the potential for bacterial seeding of the hardware. We performed a systematic review of the current data.

METHODS

A search was performed using Medline, Embase, and Ovid for articles using the keywords "cervical osteomyelitis/spondylodiscitis" and "fusion" or "instrumentation" reported from 1980 to 2017. Prospective or retrospective studies describing ≥2 patients with cervical osteomyelitis were included in the analysis; non-English reports were excluded. Individual patients were excluded from the final analysis if they had previously undergone spinal instrumentation.

RESULTS

A total of 239 patients from 24 studies met our criteria. Surgical approaches were classified as anterior-only, combined anteroposterior, and posterior-only for 64.8%, 31.9%, and 3.3% of the patients respectively. Of the patients treated using an anterior-only approach, 76.5% had received anterior plating and 85.3%, a cage or spacer implants. Of the patients who had undergone combined approaches, 85.1% underwent circumferential fixation and 14.9%, anterior debridement with posterior instrumentation. The follow-up period ranged from 6 weeks to 11 years (mean, 31.0 months). All the studies reporting the fusion rates, except for 1, reported a 100% fusion rate. The reported rates of pain improvement and neurologic recovery were favorable. The incidence of hardware failure and wound complications was 4.6% and 4.0%, respectively.

CONCLUSIONS

Despite placing instrumentation during active infection, the rates of hardware failure and wound complications were comparable to those of elective cervical spine procedures. These results suggest that surgical intervention with instrumentation is a safe treatment option for patients with cervical spine osteomyelitis.

Epidemiology, Microbiological Diagnosis, and Clinical Outcomes in Pyogenic Vertebral Osteomyelitis: A 10-year Retrospective Cohort Study

Background

Pyogenic vertebral osteomyelitis (PVO) is rising in incidence, but optimal methods of investigation and duration of antibiotic therapy remain controversial.

Methods

We conducted a single-center retrospective cohort study of PVO at an Australian teaching hospital. We included all adults with a first episode of PVO between 2006 and 2015. PVO was defined based on the presence of prespecified clinical and radiological criteria. The main exposures of interest were investigation strategy and antibiotic treatment. The main outcome measures were duration of hospital admission, mortality during index admission, symptom resolution during index admission, and attributable readmission within 2 years.

Results

Of 129 included patients, 101 (78%) had a causative organism identified. Patients with an identified pathogen were more likely to be febrile (75% compared with 29%, P < .001) and had a higher mean admission C-reactive protein (207 vs 54, P < .001) compared with patients without an identified pathogen. However, they were less likely to experience an adverse outcome (death or attributable readmission within 2 years; adjusted odds ratio, 0.36; 95% confidence interval, 0.13–0.99; P = .04). Open biopsy of vertebral tissue had a higher diagnostic yield (70%) than fine needle aspirate (41%) or core biopsy (30%). Despite receiving a median of 6 weeks of intravenous antibiotics, only 15% of patients had a full recovery on discharge from index admission.

Conclusions

Clinical outcomes for patients with PVO were poor. Obtaining a microbiological diagnosis is associated with a better outcome. However, prospective and randomized studies are essential to establishing optimal investigation and treatment pathways.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Clinical characteristics, treatments, and outcomes of hematogenous pyogenic vertebral osteomyelitis, 12-year experience from a tertiary hospital in central Taiwan

BACKGROUND

In Taiwan, studies about hematogenous pyogenic vertebral osteomyelitis (HPVO) are limited. We conducted a retrospective study to evaluate the clinical presentations, treatment, and outcomes of patients with the diagnosis of HPVO.

METHOD

This 12.5-year retrospective study included patients with a diagnosis of HPVO. Medical records of all HPVO patients were thoroughly reviewed and their clinical data were analyzed by the SPSS software.

RESULT

414 HPVO cases were included and the mean age was 61.6 ± 13.4 years. The mean duration of symptoms was 29 ± 35.3 days and pain over the affected site was reported by most patients (86.0%). Gram-positive bacteria, especially Staphylococcus aureus (162/399 = 40.6%), were the main HPVO pathogens. Escherichia coli (42/399 = 10.5%) was the most common gram-negative isolate. Surgery was performed in 68.8% of cases and the mean duration of total antibiotic treatment was 104.7 ± 77.7 days. All-cause mortality and recurrence rates were 6.3% and 18.8%, respectively. In multivariate analysis, polymicrobial infection (OR: 4.154, 95% CI: 1.039-16.604, p = 0.044), multiple vertebral body involvement (OR: 2.202, 95% CI: 1.088-4.457, p = 0.028), abscess formation treated with antibiotics alone (OR: 2.912, 95% CI: 1.064-7.966, p = 0.037), and the duration of antimicrobial treatment less than 4 weeks (OR: 3.737, 95% CI: 1.195-11.683, p = 0.023) were associated with HPVO recurrence.

CONCLUSION

In Taiwan, HPVO mainly affected the elderly and S. aureus remained the most common HPVO pathogen. In patients with risk factors associated with HPVO recurrence, a longer duration (≥6 weeks) of antimicrobial therapy is suggested.

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.

Comparison of characteristics of culture-negative pyogenic spondylitis and tuberculous spondylitis: a retrospective study

Background

Differences between the characteristics of culture positive pyogenic spondylitis (CPPS) and tuberculous spondylitis (TS) are well known. However, differences between the characteristics of culture negative pyogenic spondylitis (CNPS) and TS have not been reported; these would be more helpful in clinical practice especially when initial microbiologic examination of blood and/or biopsy tissue did not reveal the causative bacteria in patients with infectious spondylitis.

Methods

We performed a retrospective review of the medical records of patients with CNPS and TS. We compared the characteristics of 71 patients with CNPS with those of 94 patients with TS.

Results

Patients with TS had more previous histories of tuberculosis (9.9 vs 22.3 %, p = 0.034), simultaneous tuberculosis other than of the spine (0 vs 47.9 %, p < 0.001), and positive results in the interferon-gamma release assay (27.6 vs 79.2 %, p < 0.001). Fever (15.5 vs. 31.8 %, p = 0.018), psoas abscesses (15.5 vs 33.0 %, p = 0.011), and paravertebral abscesses (49.3 vs. 74.5 %, p = 0.011) were also more prevalent in TS than CNPS.

Conclusions

Different from or contrary to the previous comparisons between CPPS and TS, fever, psoas abscesses, and paravertebral abscesses are more common in patients with TS than in those with CNPS.

Outcome of conservative and surgical treatment of pyogenic spondylodiscitis: a systematic literature review

BACKGROUND

Spondylodiscitis is a spinal infection affecting primarily the intervertebral disk and the adjacent vertebral bodies. Currently many aspects of the treatment of pyogenic spondylodiscitis are still a matter of debate.

PURPOSE

The aim of this study was to review the currently available literature systematically to determine the outcome of patients with pyogenic spondylodiscitis for conservative and surgical treatment strategies.

METHODS

A systematic electronic search of MEDLINE, EMBASE, Cochrane Collaboration, and Web of Science regarding the treatment of pyogenic spondylodiscitis was performed. Included articles were assessed on risk of bias according the Cochrane Handbook for Systematic Reviews of Interventions, and the quality of evidence and strength of recommendation was evaluated according the GRADE approach.

RESULTS

25 studies were included. Five studies had a high or moderate quality of evidence. One RCT suggest that 6 weeks of antibiotic treatment of pyogenic spondylodiscitis results in a similar outcome when compared to longer treatment duration. However, microorganism-specific studies suggest that at least 8 weeks of treatment is required for S. aureus and 8 weeks of Daptomycin for MRSA. The articles that described the outcome of surgical treatment strategies show that a large variety of surgical techniques can successfully treat spondylodiscitis. No additional long-term beneficial effect of surgical treatment could be shown in the studies comparing surgical versus antibiotic only treatment.

CONCLUSION

There is a strong level of recommendation for 6 weeks of antibiotic treatment in pyogenic spondylodiscitis although this has only been shown by one recent RCT. If surgical treatment is indicated, it has been suggested by two prospective studies with strong level of recommendation that an isolated anterior approach could result in a better clinical outcome.

Long-term prognosis and causes of death after spondylodiscitis: A Danish nationwide cohort study

BACKGROUND

Data on long-term prognosis after spondylodiscitis are scarce. The purpose of this study was to determine long-term mortality and the causes of death after spondylodiscitis.

METHODS

A nationwide, population-based cohort study using national registries of patients diagnosed with non-post-operative pyogenic spondylodiscitis from 1994-2009, alive 1 year after diagnosis (n = 1505). A comparison cohort from the background population individually matched for sex and age was identified (n = 7525). Kaplan-Meier survival curves were constructed and Poisson regression analyses used to estimate mortality rate ratios (MRR).

RESULTS

Three hundred and sixty-five patients (24%) and 1115 individuals from the comparison cohort (15%) died. Unadjusted MRR for spondylodiscitis patients was 1.76 (95% CI = 1.57-1.98) and 1.47 (95% CI = 1.30-1.66) after adjustment for comorbidity. No deaths were observed in 128 patients under the age of 16 years. Siblings of patients did not have increased long-term mortality compared with siblings of the individuals from the comparison cohort. This study observed increased mortality due to infections (MRR = 2.57), neoplasms (MRR = 1.40), endocrine (MRR = 3.72), cardiovascular (MRR = 1.62), respiratory (MRR = 1.71), gastrointestinal (MRR = 3.35), musculoskeletal (MRR = 5.39) and genitourinary diseases (MRR = 3.37), but also due to trauma, poisoning and external causes (MRR = 2.78), alcohol abuse-related diseases (MRR = 5.59) and drug abuse-related diseases (6 vs 0 deaths, MRR not calculable).

CONCLUSIONS

Patients diagnosed with spondylodiscitis have increased long-term mortality, mainly due to comorbidities, particularly substance abuse.

Differential diagnosis between tuberculous spondylodiscitis and pyogenic spontaneous spondylodiscitis: a multicenter descriptive and comparative study

BACKGROUND CONTEXT

Although tuberculous and pyogenic spondylodiscitis are common causes of spinal infections, their protean manifestation complicates differential diagnosis.

PURPOSE

The clinical, laboratory, and radiologic characteristics of tuberculous and pyogenic spontaneous spondylodiscitis were compared in this study.

STUDY DESIGN

This multicenter retrospective study was conducted in 11 teaching hospitals in the Republic of Korea from January 2011 to December 2013.

PATIENT SAMPLE

Study subjects included adult patients (≥18 years) diagnosed with tuberculous (n=60) or pyogenic (n=117) spontaneous spondylodiscitis.

OUTCOME MEASURES

Risk factors for tuberculous spondylodiscitis were determined, and their predictive performance was evaluated.

METHODS

Multivariate logistic regression analysis was performed to determine predictors independently associated with tuberculous spondylodiscitis. Receiver-operating characteristic curve analysis using the presence or absence of risk factors was used to generate a risk index to identify patients with increased probability of tuberculous spondylodiscitis.

RESULTS

Of 177 patients, multivariate logistic regression analysis showed that patients with tuberculous spondylodiscitis (n=60) were more frequently women, with increased nonlumbar spinal involvement and associated non-spinal lesions, delayed diagnosis, higher serum albumin levels, reduced white blood cell counts, and lower C-reactive protein and procalcitonin levels. Among 117 patients with pyogenic spondylodiscitis, the most frequent causative microorganism was Staphylococcus aureus (64.1%). The mean diagnostic delay was significantly shorter, which may reflect higher clinical expression leading to earlier diagnosis. A combination of clinical data and biomarkers had better predictive value for differential diagnosis compared with biomarkers alone, with an area under the curve of 0.93, and sensitivity, specificity, and positive and negative predictive values of 95.0%, 79.5%, 70.4%, and 96.9%, respectively.

CONCLUSIONS

This study provides guidance for clinicians to predict the causative organisms of spondylodiscitis in uncertain situations and before culture or pathologic examinations. Clinical data and single biomarkers combined can be useful for differential diagnoses between tuberculous and pyogenic spondylodiscitis.

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.

Successful use of tigecycline for treatment of culture-negative pyogenic vertebral osteomyelitis

BACKGROUND

Pyogenic vertebral osteomyelitis (PVO) is a severe infection that requires prolonged antimicrobial therapy and/or surgical interventions. Limited data are available on the safety and clinical efficacy of tigecycline in PVO. The objective of this study was to describe the clinical outcomes of patients treated with tigecycline for culture-negative PVO that was unresponsive to empirical antibiotic therapy including intravenous ampicillin-sulbactam plus ciprofloxacin or ampicillin-sulbactam alone.

METHODS

We retrospectively reviewed 15 patients with culture-negative PVO from 2009 through 2014. The patients received tigecycline as secondary empirical therapy, after not responding to the first empirical therapy. Clinical success was defined as recovery from symptoms and normalization of laboratory parameters at the end of therapy. Continued clinical success at 24 weeks after the end of the therapy was defined as sustained clinical success.

RESULTS

Tigecycline treatment was completed in 14 patients and discontinued in 1 due to severe nausea and vomiting. The mean age of the patients was 67.7 years (range 58-77 years), and 57.1% (8/14) were women. In all, 78.6% (11/14) of patients had risk factors for probable resistant staphylococcal and gram-negative infections such as diabetes mellitus, presence of hemodialysis catheters, and prior antibiotic usage. The average duration of tigecycline treatment was 8.3 weeks (range 6-11 weeks). Sustained clinical success was obtained in all patients.

CONCLUSIONS

Tigecycline should be considered as an alternative agent for the treatment of PVO in selected patients due to microbiological activity against resistant gram-positive and gram-negative bacteria.

Therapeutic outcomes of hematogenous vertebral osteomyelitis with instrumented surgery

BACKGROUND

Patients with hematogenous vertebral osteomyelitis (HVO) occasionally require instrumentation for spinal stabilization. However, placing instrumentation in the setting of spinal infection raises concerns about recurrent infection due to bacteria adhering to the foreign material. In this study, we evaluated the therapeutic outcomes of patients with HVO who underwent instrumented surgery.

METHODS

We conducted a retrospective chart review of adult patients with microbiologically diagnosed HVO who underwent surgical intervention in 5 tertiary care hospitals over an 8-year period.

RESULTS

A total of 153 patients with HVO underwent surgical management for their infections. Of these 153 patients, 94 (61.4%) underwent surgical debridement alone (noninstrumented surgery) and 59 (38.6%) underwent surgical debridement and instrumentation (instrumented surgery). The median durations of antibiotic therapy were 66 and 80 days for the noninstrumentation and instrumentation groups, respectively (P = .22). Clinical outcomes were similar between the groups, including rates of infection-related death (2.1% vs 0%; P = .52), primary failure (1.1% vs 5.1%; P = .30), and recurrence (4.8% vs 6.8%; P = .72). Among the instrumentation group, there was a significant decreasing trend for recurrence according to total duration of antibiotic therapy: 22.2% (4-6 weeks), 9.1% (6-8 weeks), and 2.6% (≥ 8 weeks; P = .04). Duration of pre-instrumentation antibiotic therapy and single-stage operation (vs 2-stage operation) were not risk factors for recurrence.

CONCLUSIONS

Spinal instrumentation in patients with HVO may be safe with pathogen-directed prolonged antibiotic therapy and should not be abandoned or delayed solely because of the risk of recurrence.