Spinal infections: evolving concepts:

MRI findings and classification of brucella spondylitis: a China multicenter study

OBJECTIVES

To propose a magnetic resonance imaging (MRI) classification of brucellosis spondylitis (BS) to determine a standard treatment method and a standard of post-treatment MRI follow-up.

METHODS

This is a multicenter retrospective cohort study. All patients diagnosed with BS at six hospitals for 12 years, were included in the study. Data were collected retrospectively from the medical records of the patients. The classification of the cases was based on MRI. We analyzed MRI features of BS was categorized them into three types.

RESULTS

Six hundred fifteen patients were included in the study, 78.9% of whom were males. The mean age was 53.05 ± 11.06 years. Involvement of single vertebrae occurred in 6.2% of patients, while 72.7% involved two vertebrae and 21.1% involvement of more than two vertebrae. The most common of the lumbar spine was 64.6%. The main findings of MRI were affected vertebral endplate 2/3 above (60.7%), intervertebral space narrow (77.9%), intervertebral disc involvement (83.6%), paravertebral abscess (50.9%), disc abscess (49.6%), epidural abscess (43.3%), vertebra height change (22.1%), psoas abscess (22.0%), and abnormal vertebral accessory (10.2%). MR imaging of BS was categorized into three types. Type I: 57 (9.3%) patients; Type II: 526 (85.5%) patients, including IIa (26.5%), IIb (36.9%), and IIc (22.1%); Type IV: vertebral appendage type, 63 (10.2%) cases; Type III: 32 (5.2%) patients.

CONCLUSIONS

MRI features of multicenter data can provide theoretical support for diagnosing BS. MRI classification of BS can afford better help for clinical treatment and follow-up after clinical treatment.

A Comparative Factor Analysis and New Magnetic Resonance Imaging Scoring System for Differentiating Pyogenic Versus Tuberculous Spondylodiscitis

OBJECTIVE

This study aimed to compare and analyze differences in clinical and magnetic resonance imaging (MRI) findings between tuberculous spondylodiscitis (TbS) and pyogenic spondylodiscitis (PyS), and to develop and validate a simplified multiparameter MRIbased scoring system for differentiating TbS from PyS.

METHODS

We compared predisposing factors in 190 patients: 123 with TbS and 67 with PyS, confirmed by laboratory tests, culture, or pathology. Data encompassing patient demographics, clinical characteristics, laboratory results, and MRI findings were collected between 2015 and 2020. Data were analyzed using logistic regression methods, and selected coefficients were transformed into an MRI-based scoring system. Internal validation was performed using bootstrapping method.

RESULTS

Univariate analysis revealed that the significant risk factors associated with TbS included thoracic lesions, vertebral destruction > 50%, intraosseous abscess, thin-walled abscess, well-defined paravertebral abscess, subligamentous spreading, and epidural abscess. Multivariate analysis revealed that only thoracic lesions, absence of epidural phlegmon, subligamentous spreading, intraosseous abscesses, well-defined paravertebral abscesses, epidural abscesses, and absence of facet joint arthritis were independent predictive factors for TbS (all p < 0.05). These potential predictors were used to derive an MRI scoring system. Total scores ≥ 14/29 points significantly predicted the probability of TbS, with a sensitivity of 97.58%, specificity of 92.54%, and an area under the curve of 0.96 (95% confidence interval, 125.40-3,257.95).

CONCLUSION

This simplified MRI-based scoring system for differentiating TbS from PyS helps guide appropriate treatment when the causative organism is not identified.

The Potential of a CT-Based Machine Learning Radiomics Analysis to Differentiate Brucella and Pyogenic Spondylitis

Background

Pyogenic spondylitis (PS) and Brucella spondylitis (BS) are common spinal infections with similar manifestations, making their differentiation challenging. This study aimed to explore the potential of CT-based radiomics features combined with machine learning algorithms to differentiate PS from BS.

Methods

This retrospective study involved the collection of clinical and radiological information from 138 patients diagnosed with either PS or BS in our hospital between January 2017 and December 2022, based on histopathology examination and/or germ isolations. The region of interest (ROI) was defined by two radiologists using a 3D Slicer open-source platform, utilizing blind analysis of sagittal CT images against histopathological examination results. PyRadiomics, a Python package, was utilized to extract ROI features. Several methods were performed to reduce the dimensionality of the extracted features. Machine learning algorithms were trained and evaluated using techniques like the area under the receiver operating characteristic curve (AUC; confusion matrix-related metrics, calibration plot, and decision curve analysis to assess their ability to differentiate PS from BS. Additionally, permutation feature importance (PFI; local interpretable model-agnostic explanations (LIME; and Shapley additive explanation (SHAP) techniques were utilized to gain insights into the interpretabilities of the models that are otherwise considered opaque black-boxes.

Results

A total of 15 radiomics features were screened during the analysis. The AUC value and Brier score of best the model were 0.88 and 0.13, respectively. The calibration plot and decision curve analysis displayed higher clinical efficiency in the differential diagnosis. According to the interpretation results, the most impactful features on the model output were wavelet LHL small dependence low gray-level emphasis (GLDN).

Conclusion

The CT-based radiomics models that we developed have proven to be useful in reliably differentiating between PS and BS at an early stage and can provide a reliable explanation for the classification results.

Vertebral Osteomyelitis Secondary to a Retroperitoneal Abscess in an Adolescent Male: A Case Report

Pyogenic vertebral osteomyelitis (PVO) is included in a spectrum of spine infections called spondylodiscitis. It is commonly caused by hematogenous seeding. The annual incidence of spondylodiscitis is 2.4 per 100,000 person-years and the incidence triples for people over seventy.

We report a case of a previously healthy 14-year-old male with a rare presentation of vertebral osteomyelitis associated with a large retroperitoneal abscess of unknown origin, manifested with flank pain, back pain, and fever, and treated with antibiotics with good short-term outcomes.

We concluded that vertebral osteomyelitis in adolescent patients could manifest with back or flank pain. Moreover, it can occur as an extraperitoneal manifestation of a retroperitoneal abscess.

Minimally Invasive Spine Stabilization for Pyogenic Spondylodiscitis: A 23-Case Series and Review of Literature

Background and Objectives: The incidence of pyogenic spondylodiscitis has been increasing due to the aging of the population. Although surgical treatment is performed for refractory pyogenic spondylodiscitis, surgical invasiveness should be considered. Recent minimally invasive spine stabilization (MISt) using percutaneous pedicle screw (PPS) can be a less invasive approach. The purpose of this study was to evaluate surgical results and clinical outcomes after MISt with PPS for pyogenic spondylodiscitis. Materials and Methods: Clinical data of patients who underwent MISt with PPS for pyogenic spondylitis were analyzed. Results: Twenty-three patients (18 male, 5 female, mean age 67.0 years) were retrospectively enrolled. The mean follow-up period was 15.9 months after surgery. The causative organism was identified in 16 cases (69.6%). A mean number of fixed vertebrae was 4.1, and the estimated blood loss was 145.0 mL. MISt with PPS was successfully performed in 19 of 23 patients (82.6%). Four cases (17.4%) required additional anterior debridement and autologous iliac bone graft placement. CRP levels had become negative at an average of 28.4 days after surgery. There was no major perioperative complication and no screw or rod breakages during follow-up. Conclusions: MISt with PPS would be a less invasive approach for pyogenic spondylodiscitis in elderly or immunocompromised patients.

Outcome of one-stage percutaneous endoscopic debridement and lavage combined with percutaneous pedicle screw fixation for lumbar pyogenic spondylodiscitis

BACKGROUND

This study assessed the therapeutic effect of one-stage percutaneous endoscopic debridement and lavage (PEDL) combined with percutaneous pedicle screw fixation (PPSF) in the treatment of lumbar pyogenic spondylodiscitis.

METHODS

From March 2017 to October 2019, 51 patients diagnosed with pyogenic spondylodiscitis underwent PPSF followed by PEDL in our department. Biopsy specimens were examined for microorganisms and evaluated histopathologically. Clinical outcomes were assessed by physical examination, routine serological testing, visual analogue scale (VAS), Oswestry Disability Index (ODI) and imaging studies.

RESULTS

Of the enrolled patients, the operation time ranged from 90 min to 114 min every level with an average of 102 min, and the average drainage time ranged from 6 days to 10 days with an average of 7.4 days. All patients who complained of lower back pain symptoms were more relieved than before surgery. Causative pathogens were identified in 20 of 51 biopsy specimens; Staphylococcus aureus was the most prevalent. However, there were eight patients with postoperative complications. The mean follow-up was 25.0 ± 3.8 (range: 20-32) months. Inflammatory markers showed that infection was controlled. The VAS and ODI improved significantly. At the last follow-up, magnetic resonance imaging showed that the infected lesions had disappeared.

CONCLUSION

PEDL supplementing PPSF may be useful for patients with single-level lumbar pyogenic spondylodiscitis, as it is minimally invasive, especially for patients who cannot undergo conventional open surgery due to poor health or advanced age.

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.

Single-stage debridement via autogenous iliac bone graft through the OLIF corridor and lateral fixation in treating spontaneous single-level lumbar pyogenic spondylodiscitis

BACKGROUND

The aim of the present study was to investigate the efficacy and safety of mini-open oblique debridement and lumbar interbody fusion combined with lateral screw fixation for treating single-level pyogenic spondylodiscitis.

METHODS

Twelve patients with single-level lumbar pyogenic spondylodiscitis underwent OLIF combined with lateral screw fixation were analyzed. Patients underwent follow-up for 12 to 24 months. The clinical characteristics, etiological examinations, operative time, intraoperative blood loss, Oswestry Disability Index (ODI), visual analog scale score (VAS), postoperative complications, and the bony fusion rate were recorded.

RESULTS

The mean follow-up period of time was 14.8 months. The average operative time and intra-operative blood loss were 129.0 ± 19.76 min and 309.2 ± 92.96 mL, respectively. No severe intra-operative complications were observed during surgery, except in 1 case that develops abdominal pain and distension after surgery, 2 cases that develop left-sided transient thigh pain/numbness and 8 cases that complains of donor site (iliac crest) pain. All of these symptoms disappeared 8 weeks after surgery. Tissue sample cultures were obtained from all patients intraoperatively and four (33.3%) were positive, including 2 with Staphylococcus aureus, 1 with Staphylococcus epidermidis, and 1 with Escherichia coli. During an average of 22.5 ± 2.1 days (range, 14-29 days) after surgery, WBC, CPR, and ESR levels in all patients had returned to normal. All patients were pain free with no recurring infection. Solid bony fusions were observed in all cases within 6 months, including 10 with I grade fusion, 2 with II grade fusion according to the classification suggested by Burkus et al. No fixation failure was observed during follow up and solid bony fusions were observed in all 12 patients at finally follow-up. A significant postoperative increase was also observed in the mean segmental height and lordosis (P < 0.05), followed by a slight decrease of segmental height and lordosis at final follow-up. At the final follow up, the mean VAS (1.5 ± 0.6) and ODI (18.9 ± 7.6) were significantly lower than VAS (8.4 ± 2.7) and ODI (71.2 ± 16.5) before surgery (P < 0.01).

CONCLUSION

Single-stage debridement with autogenous iliac bone graft through the OLIF corridor and lateral fixation was a feasible surgical approach in our consecutive 12 cases of pyogenic spondylitis.

A diagnostic model for differentiating tuberculous spondylitis from pyogenic spondylitis on computed tomography images

OBJECTIVES

To develop and evaluate a logistics regression diagnostic model based on computer tomography (CT) features to differentiate tuberculous spondylitis (TS) from pyogenic spondylitis (PS).

METHODS

Demographic and clinical features were collected from the Electronic Medical Record System. Data of bony changes seen on CT images were compared between the PS (n = 61) and TS (n = 51) groups using the chi-squared test or t test. Based on features that were identified to be significant, a diagnostic model was developed from a derivation set (two thirds) and evaluated in a validation set (one third). The sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were calculated.

RESULTS

The width of bone formation around the vertebra and sequestrum was greater in the TS group. There were significant differences between the two groups in the horizontal and longitudinal location of erosion and the morphology of axial bone destruction and sagittal residual vertebra. Kyphotic deformity and overlapping vertebrae were more common in the TS group. A diagnostic model that included eight predictors was developed and simplified to include the following six predictors: width of the bone formation surrounding the vertebra, longitudinal location, axial-specific erosive morphology, specific morphology of the residual vertebra, kyphotic deformity, and overlapping vertebrae. The simplified model showed good sensitivity, specificity, and total accuracy (85.59%, 87.80%, and 86.50%, respectively); the AUC was 0.95, indicating good clinical predictive ability.

CONCLUSIONS

A diagnostic model based on bone destruction and formation seen on CT images can facilitate clinical differentiation of TS from PS.

KEY POINTS

• We have developed and validated a simple diagnostic model based on bone destruction and formation observed on CT images that can differentiate tuberculous spondylitis from pyogenic spondylitis. • The model includes six predictors: width of the bone formation surrounding the vertebra, longitudinal location, axial-specific erosive morphology, specific morphology of the residual vertebra, kyphotic deformity, and overlapping vertebrae. • The simplified model has good sensitivity, specificity, and total accuracy with a high AUC, indicating excellent predictive ability.

18F-FDG PET/CT contribution to tuberculous vertebral osteomyelitis diagnosis: a case report

Tuberculous vertebral osteomyelitis (TVO) is an extrapulmonary tuberculosis form characterized by difficulty and delay in diagnosis. PET/CT is a valuable, well-established tool in the diagnostic workup of cancer and fever of unknown origin, which is increasingly appreciated in the management of infectious diseases. We report a TVO case where PET/CT had a valuable contribution towards diagnosis and monitoring of treatment response, highlighting its advantages and future perspectives when dealing with infectious diseases.

The Value of MR Imaging in Comparative Analysis of Spinal Infection in Adults: Pyogenic Versus Tuberculous

OBJECTIVE

Differentiating pyogenic spondylitis (PS) and tuberculous spondylitis (TS) is challenging but critical in clinical practice. Accurate diagnosis and early treatment are crucial to preventing further progression of disease. Magnetic resonance imaging (MRI) is considered the best method for the diagnosis of spinal infection, but results remain imprecise; therefore, by comparing and analyzing the MRI findings of spinal infections, we intend to identify key distinguishing features between PS and TS, and with that establish a systematic scoring method to help clinicians.

METHODS

The MRI features of 70 cases of spinal infection (32 cases of PS, 38 cases of TS), confirmed by pathology or clinical diagnosis, were retrospectively analyzed. The receiver operating characteristic curve was used to analyze the diagnostic efficacy of the MRI parameter scores in PS and TS.

RESULTS

Among the 70 cases, the average age was 54.5 years, and 43 were male. Sixteen parameters were significantly different between the PS and TS groups. We hypothesized that a diagnosis of PS could be made when the number of parameters characteristic of PS exceeded the number of parameters characteristic of TS, and vice versa. We randomly selected 70% (49 patients) of the 70 patients for analysis, and then validated in the remaining 30% (21 patients) of cases. Using 0.5 as the cutoff value, of the remaining 21 patients, the correct coincidence rate was 95.23%, sensitivity was 91.67%, specificity was 100%, false-positive rate was 0%, and false-negative rate was 8.3%. The MRI parameter scores of PS and TS were analyzed with the receiver operating characteristic; area under the curve was 1.00.

CONCLUSIONS

Our systematic scoring system of MRI parameters is helpful in differentiating PS and TS.

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

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

Magnetic Resonance Imaging in Differentatial Diagnosis of Pyogenic Spondylodiscitis and Tuberculous Spondylodiscitis

BACKGROUND

Infectious spondylodiscitis is characterized by the involvement of two adjacent vertebrae and the intervening disc. Incidence rate of the disease is estimated at 0.4-2 cases per 100000 per year. Staphylococcus aureus is the most common infectious agent causing pyogenic spondylodiscitis. Non-pyogenic infections of the spine are most frequently caused by Mycobacterium tuberculosis, and fungi. Clinical symptoms are nonspecific. Early diagnosis and appropriate treatment can prevent unfavorable irreversible sequela for the patient. Significant developments in techniques of imaging of pathological tissues raised expectations among the clinicians regarding possibility to distinguish between tuberculous spondylodiscitis and pyogenic spondylodiscitis on MR images. The aim of this study was to identify and differentiate between features of tuberculous and pyogenic spondylodiscitis on MR images.

MATERIAL/METHODS

We performed retrospective analysis of MR images obtained from 34 patients with confirmed spondylodiscitis (18 with pyogenic spondylodiscitis, and 16 with tuberculous spondylodiscitis). Data acquisition was performed using 1.5 T MRI scanners where images were obtained using similar protocols. T2 TIRM and T1-weighted images with and without contrast enhancement were subject to assessment in coronal, axial and sagittal planes.

RESULTS

Characteristic features of pyogenic spondylodiscitis include: involvement of the lumbar spine, ill-defined paraspinal abnormal contrast enhancement, diffuse/homogeneous contrast enhancement of vertebral bodies, low-grade destruction of vertebral bodies, hyperintense/homogeneous signal from the vertebral bodies on T2 TIRM images. Prevailing features of tuberculous spondylodiscitis included: involvement of the thoracic spine, involvement of 2 or more adjacent vertebral bodies, severe destruction of the vertebral body, focal/heterogeneous contrast enhancement of vertebral bodies, heterogeneous signal from the vertebral bodies on T2 TIRM images, well-defined paraspinal abnormal contrast enhancement, paraspinal and epidural abscesses, meningeal enhancement at the affected spine level.

CONCLUSIONS

Comparison of MR images of patients diagnosed with pyogenic spondylodiscitis and tuberculous spondylodiscitis allowed identification of individual characteristics for preliminary differentiation between TB and infectious spondylodiscitis and thereby enabling proper treatment.

Health care associated hematogenous pyogenic vertebral osteomyelitis: a severe and potentially preventable infectious disease

Although hematogenous pyogenic spinal infections have been related to hemodialysis (HD), catheter-related sepsis, and sporadically, to other nosocomial infections or procedures, in most recent studies and reviews the impact of nosocomial infection as a risk factor for vertebral osteomyelitis (VO) is not well established. The aim of our study was to describe the risk factors, infectious source, etiology, clinical features, therapy, and outcome of health care associated VO (HCAVO), and compare them with community-acquired VO (CAVO) cases.A retrospective cohort study of consecutive patients with hematogenous VO was conducted in our third-level hospital between 1987 and 2011. HCAVO was defined as onset of symptoms after 1 month of hospitalization or within 6 months after hospital discharge, or ambulatory manipulations in the 6 months before the diagnosis.Over the 25-year study period, among 163 hematogenous pyogenic VO, 41 (25%) were health care associated, a percentage that increased from 15% (9/61) in the 1987-1999 period to 31% (32/102) in the 2000-2011 period (P < 0.01). The presumed source of infection was an intravenous catheter in 14 (34%), cutaneous foci in 8 (20%), urinary tract in 7 (17%), gastrointestinal in 3 (7%), other foci in 3 (7%), and unknown in 6 (15%). Staphylococcus aureus was the most frequently isolated microorganism (14 cases, 34%), followed by coagulase-negative Staphylococci (CoNS) in 6 (15%), and Enterobacteriaceae in 6 (15%) cases.Compared with CAVO cases, patients with HCAVO were older (mean 66.0 SD 13.0 years vs 60.5 SD 15.5 years), had more underlying conditions (73% vs 50%, P < 0.05), neoplasm/immunosuppression (39% vs 7%, P < 0.005), chronic renal failure (19% vs 4%, P < 0.001), a known source of infection (85% vs 54% P < 0.05), Candida spp (7% vs 0%, P < 0.01) or CoNS infections (15% vs 2%, P < 0.05), higher mortality (15% vs 6%, P = 0.069), and a higher relapse rate in survivors (9% vs 1%, P < 0.05).Presently, in our setting, one-third of hematogenous pyogenic VO infections are health care associated, and a third of these are potentially preventable catheter-related infections. Compared with CAVO, in health care associated hematogenous VO, mortality and relapse rates are higher; hence, further prevention measures should be assessed.

Pyogenic and non-pyogenic spinal infections: emphasis on diffusion-weighted imaging for the detection of abscesses and pus collections

The incidence of spinal infections has increased in the past two decades, owing to the increasing number of elderly patients, immunocompromised conditions, spinal surgery and instrumentation, vascular access and intravenous drug use. Conventional MRI is the gold standard for diagnostic imaging; however, there are still a significant number of misdiagnosed cases. Diffusion-weighted imaging (DWI) with a b-value of 1000 and apparent diffusion coefficient (ADC) maps provide early and accurate detection of abscess and pus collection. Pyogenic infections are classified into four types of extension based on MRI and DWI findings: (1) epidural/paraspinal abscess with spondylodiscitis, (2) epidural/paraspinal abscess with facet joint infection, (3) epidural/paraspinal abscess without concomitant spondylodiscitis or facet joint infection and (4) intradural abscess (subdural abscess, purulent meningitis and spinal cord abscess). DWI easily detects abscesses and demonstrates the extension, multiplicity and remote disseminated infection. DWI is often a key image in the differential diagnosis. Important differential diagnoses include epidural, subdural or subarachnoid haemorrhage, cerebrospinal fluid leak, disc herniation, synovial cyst, granulation tissue, intra- or extradural tumour and post-surgical fluid collections. DWI and the ADC values are affected by susceptibility artefacts, incomplete fat suppression and volume-averaging artefacts. Recognition of artefacts is essential when interpreting DWI of spinal and paraspinal infections. DWI is not only useful for the diagnosis but also for the treatment planning of pyogenic and non-pyogenic spinal infections.

Tuberculosis the great mimicker: 18F-fludeoxyglucose positron emission tomography/computed tomography in a case of atypical spinal tuberculosis

Tuberculosis (TB) has aptly been called the great mimicker. A 14-year-old boy, who had been treated for Hodgkin's Lymphoma 2 years back and had been in remission, underwent a whole body 18F-fludeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan, owing to a recent onset of backache and difficulty in walking. The study showed an FDG avid destructive lesion of the posterior elements of the sixth, seventh and eighth dorsal vertebrae along with a hypermetabolic collection in the adjacent paraspinal muscles with extension into the spinal canal, causing encasement of the thecal sac as well. Based on this constellation of findings, a diagnosis of atypical spinal TB was made, which was subsequently proven on histopathology. The present case illustrates that spinal TB, including the atypical form can be diagnosed on PET/CT even in clinically unsuspected cases.

Propionibacterium acnes: an underestimated pathogen in implant-associated infections

The role of Propionibacterium acnes in acne and in a wide range of inflammatory diseases is well established. However, P. acnes is also responsible for infections involving implants. Prolonged aerobic and anaerobic agar cultures for 14 days and broth cultures increase the detection rate. In this paper, we review the pathogenic role of P. acnes in implant-associated infections such as prosthetic joints, cardiac devices, breast implants, intraocular lenses, neurosurgical devices, and spine implants. The management of severe infections caused by P. acnes involves a combination of antimicrobial and surgical treatment (often removal of the device). Intravenous penicillin G and ceftriaxone are the first choice for serious infections, with vancomycin and daptomycin as alternatives, and amoxicillin, rifampicin, clindamycin, tetracycline, and levofloxacin for oral treatment. Sonication of explanted prosthetic material improves the diagnosis of implant-associated infections. Molecular methods may further increase the sensitivity of P. acnes detection. Coating of implants with antimicrobial substances could avoid or limit colonization of the surface and thereby reduce the risk of biofilm formation during severe infections. Our understanding of the role of P. acnes in human diseases will likely continue to increase as new associations and pathogenic mechanisms are discovered.

Propionibacterium acnes delayed infection following spinal surgery with instrumentation

Propionibacterium acnes detection in culture media was previously considered a contamination but recently its infectious role was discovered in post-spinal surgery infections. P. acnes might be introduced during surgery. Its diagnosis is based on non-specific clinical signs, image indications of infection, and the conclusive microbiological sign. Furthermore, its diagnosis is difficult because of slow growth rate and low virulence, delaying its presentation. Usually, the infection is manifested after a couple of months or years. Here, a 65-year-old man presented with drainage at the site of instrumented spinal surgery performed 13 years ago. P. acnes infection was confirmed by culture with extended incubation. Our review of the literature revealed only two other reported cases of delayed P. acnes infection presenting a decade following a spinal surgery with instrumentation. This article sheds light on such delayed infections and discusses their presentation and management.

Diabetes mellitus and spinal epidural abscess: clinical or surgical treatment?

Spinal epidural abscess (SEA) is an uncommon condition and its most important predisposing factor is diabetes mellitus. Although the treatment of choice is prompt surgical abscess evacuation, followed by antibiotic therapy, successful conservative treatment of SEA has been reported in some cases. We describe a SEA case in a 23-year old white woman with diabetes for 14 years, who was successfully treated only with antibiotics, and achieved full recovery at the fourth month of follow-up.

Spinal tuberculosis: a review

Spinal tuberculosis is a destructive form of tuberculosis. It accounts for approximately half of all cases of musculoskeletal tuberculosis. Spinal tuberculosis is more common in children and young adults. The incidence of spinal tuberculosis is increasing in developed nations. Genetic susceptibility to spinal tuberculosis has recently been demonstrated. Characteristically, there is destruction of the intervertebral disk space and the adjacent vertebral bodies, collapse of the spinal elements, and anterior wedging leading to kyphosis and gibbus formation. The thoracic region of vertebral column is most frequently affected. Formation of a 'cold' abscess around the lesion is another characteristic feature. The incidence of multi-level noncontiguous vertebral tuberculosis occurs more frequently than previously recognized. Common clinical manifestations include constitutional symptoms, back pain, spinal tenderness, paraplegia, and spinal deformities. For the diagnosis of spinal tuberculosis magnetic resonance imaging is more sensitive imaging technique than x-ray and more specific than computed tomography. Magnetic resonance imaging frequently demonstrates involvement of the vertebral bodies on either side of the disk, disk destruction, cold abscess, vertebral collapse, and presence of vertebral column deformities. Neuroimaging-guided needle biopsy from the affected site in the center of the vertebral body is the gold standard technique for early histopathological diagnosis. Antituberculous treatment remains the cornerstone of treatment. Surgery may be required in selected cases, e.g. large abscess formation, severe kyphosis, an evolving neurological deficit, or lack of response to medical treatment. With early diagnosis and early treatment, prognosis is generally good.

False positive seroreactivity to brucellosis in tuberculosis patients: a prevalence study

Background:

The rising worldwide incidence of tuberculosis (TB) increases the demand for knowledge about its potential seroreactivity with other microbial agents. A few reports and the authors’ experiences indicate that tuberculosis may result in a false-positive brucellosis serology. This may cause a diagnostic challenge because of the close clinical resemblance of these two infections.

Objective:

The aim of the present prevalence study was to elucidate brucellosis seroreactivity in patients with active TB.

Methods:

Ninety-eight patients with newly diagnosed and active TB were studied using an enzyme-linked immunosorbent assay (ELISA) and Wright’s and Coombs–Wright’s tests. Seventy-five healthy individuals were used as controls. The patients showed signs of recovery after starting a standard anti-TB regimen and had no clinical evidence of brucellosis at a subsequent 6-month follow-up. The data were analyzed statistically by Fisher’s exact test using SPSS 11.0.

Results:

We found that 9.2% of TB patients versus 1.3% of healthy controls had positive results on the anti-Brucella IgG ELISA (P = 0.04). Five TB patients were found to have agglutination on Wright’s tests, while none of the controls showed agglutination.

Conclusion:

Active TB patients may have some seroreactivity with Brucella antigens, and Brucella IgG ELISA may give a false positive in these patients. Clinicians should consider false positive brucellosis seroreactivity in patients with active TB.

Treatment of infections of the spine

Spinal infection may involve the vertebrae, the intervertebral discs, and the adjacent intraspinal and paraspinal soft tissues. It often starts with subtle and insidious clinical signs and symptoms and may development to a debilitating and even life threatening disease. Spinal infections occur with increasing incidence and are nowadays a disease of everyday's practice for physicians treating spinal disorders. Traditionally, conservative treatment consisting of antibiosis and immobilisation is considered the first tier therapy. However, due to a considerably high rate of vertebral column instability or neurological impairment caused by the infected tissue, comprehensive experience with surgical measures have been acquired over the last decades. Thanks to tremendous improvements of surgical implants and techniques, surgical treatment has already begun to challenge conservative treatment to eventually become the first tier therapy for spinal infections in the future. This review seeks to give an overview of epidemiology, pathogenesis, diagnostic evaluation, and current nonsurgical and surgical therapy of spinal infections on the basis of the existing literature, which consists largely of retrospectively acquired data of single-centre experience with sample sizes of less than 100 patients treated with individually defined indications and treatment algorithms, and followed with various outcome parameters.

Pyogenic spondylitis in the elderly: a report from Japan with the most aging society

Pyogenic spondylitis can be life-threatening for elderly patients. To discuss the characteristics of the disease in the elderly, medical records of 103 consecutive cases of pyogenic spondylitis were reviewed. Of these, 45 cases were 65 years of age or older, and these 45 cases were enrolled into further study. In this study, the proportion of elderly patients among the total number with pyogenic spondylitis was 43.7%, and this figure has increased with the passing of time as follows: 37.5% (1988-1993), 44.4% (1994-1999), and 55.5% (2000-2005). The microorganisms were isolated in 16 cases: Staphylococcus aureus in 13 cases (including methicillin-resistant Staphylococcus aureus in nine) and others in three. Twenty-five patients had associated diseases: diabetes in 18 patients and malignant tumors in seven. Thirty patients were treated conservatively, and 15 patients underwent surgery. Twenty-six patients had paralysis. All 15 patients treated surgically, and eight of the 11 patients treated conservatively showed improvement in paralysis. Bone union was achieved in all cases except one. Our results indicate that a good outcome can be expected from conservative treatment in elderly patients as well as the young.

Nontumor lesions of spinal cord and spine

Nontumor lesions of the spinal cord and spine include developmental disorders, cystic tumor-like lesions, vascular disorders, infective diseases, demyelinating diseases, degenerative diseases, metabolic and toxic disorders, and spinal cord injury. In addition, diseases of the spine and extradural spaces secondarily cause spinal cord injury. Aside from tumors, these include developmental abnormalities, inflammatory diseases, nontumor space-occupying lesions, and tumor-like lesions such as lipomas, vascular malformations, and cysts. Awareness is required of hemostatic agents used during surgery and subsequently presenting as space-occupying lesions, which have to be differentiated from recurrent lesions. On the therapeutic front, stem cell transplantation into spinal cord for treatment of neurodegenerative disorders, spinal cord injury, and multiple sclerosis is a challenging prospect.

Posterior listhesis of a lumbar vertebra in spinal tuberculosis

The management of spinal tuberculosis, especially in children, is controversial. In children, vertebral destruction is more severe than adults because of the cartilaginous nature of their bone. Modern chemotherapy has significantly decreased mortality in spinal tuberculosis, but morbidity remains high. Without early surgery, patients can develop severe kyphosis leading to respiratory insufficiency, painful costopelvic impingement and paraplegia. Lumbar kyphosis results in early degenerative lumbar canal stenosis and is cosmetically unacceptable. We report a paediatric case of atypical spinal tuberculosis demonstrating the need for early surgical intervention to prevent significant spinal instability and neurologic deficit. A 12-year-old girl presented with increasing ambulatory difficulty and double incontinence 4 months after initiating treatment for pulmonary tuberculosis. There was no history of traumatic injury. Examination revealed severe lower limb neurologic deficit, with hypotonia, areflexia, marked sensory loss, and grade 0/5 power in both lower limbs. Plain radiographs and magnetic resonance imaging (MRI) demonstrated grade IV posterior listhesis of the L2 vertebral body over L3, cauda equina compression and bilateral psoas abscesses. Erosion of both the body and pedicle of L2 was observed. Both serology and pus drained from the psoas abscesses were negative for microorganisms. The patient underwent an L2 vertebrectomy via a left retroperitoneal approach. A titanium cage packed with autologous bone graft was inserted, and the spine was stabilized by fixation with screw and rods. Histopathology confirmed a diagnosis of tuberculosis. Eighteen months following the procedure, the patient has regained some power in her right leg and has completed her course of anti-tuberculous chemotherapy, but remains wheelchair-bound. To our knowledge, this is the first reported case of posterior listhesis secondary to spinal tuberculosis. Here, we discuss the possible management options in such a case, and the indications for surgery. As the global HIV/AIDS epidemic causes a resurgence in tuberculosis, increased awareness among the medical community regarding the atypical presentations of spinal tuberculosis is necessitated; both in the developing world where advanced clinical presentations are common, and in the developed world where spinal tuberculosis is an often-neglected diagnosis.

Utility of MRI in the follow-up of pyogenic spinal infection in children

BACKGROUND

MRI is used at an increasing rate in evaluation of pediatric spinal infections both at the time of diagnosis and in follow-up. However, the impact of MRI in follow-up has been rarely evaluated to date.

OBJECTIVE

To evaluate serial follow-up spinal MRI changes compared to clinical outcome and assess their impact on clinical management.

MATERIALS AND METHODS

All pediatric (<18 years) patients with pyogenic spinal infection over a 9-year period with at least one follow-up after treatment were included. Atypical infections were excluded.

RESULTS

We examined 35 whole-spine and 16 localized spinal scans from 17 patients (2 months to 16 years, 9F:8 M) who had 51 follow-ups done 2 weeks to 4.75 years after baseline. Seven children (41%) younger than 3 years underwent 33 follow-ups (65%); most required GA or sedation. Short-term follow-up scans demonstrated epidural and/or paraspinal soft-tissue changes correlating with clinical status and laboratory findings in all cases. However, MRI showed that bone and/or disc abnormalities continued and progressed in some cases despite clinical improvement. Long-term follow-up scans showed bone, disc and soft-tissue changes 1-3 years after baseline, despite children being symptom free. Extension of antibiotics occurred in 47% of children partly based on follow-up MRI.

CONCLUSION

Epidural and paraspinal soft-tissue changes correlated with children's clinical symptoms. Progression of bone and disc changes can manifest despite adequate clinical response. Long-term or serial routine follow-ups were not necessary. Management should be made based on clinical response.