Influence factors of metagenomic next-generation sequencing negative results in diagnosed patients with spinal infection

The aim of this study was to evaluate the influence factors of metagenomic next-generation sequencing (mNGS) negative results in the diagnosed patients with spinal infection. mNGS test was applied in a cohort of 114 patients with suspected spinal infection, among which 56 patients had a final diagnosis of spinal infection. mNGS achieved a sensitivity of 75.0% (95% CI, 61.6% to 85.6%) and a specificity of 84.5% (95% CI, 72.6% to 92.7%), using histopathology and culture results as reference. Diagnosed patients with a negative culture result had lower white blood cell account, percentage of neutrophilic granulocyte, C-reactive protein (all P<0.05) and relatively higher rate of prior antimicrobial treatment history (P=0.059). However, diagnosed patients with a negative mNGS result did not have such difference with mNGS-positive patients, suggesting that mNGS was not strictly limited by the above indicators, which presented the advantages of this technique from another point of view.

Application of Metagenomic Next-Generation Sequencing in Suspected Spinal Infectious Diseases

OBJECTIVE

This study aimed to explore the clinical efficacy of metagenomic next-generation sequencing (mNGS) in diagnosing and treating suspected spinal infectious diseases.

METHODS

Between October 2022 to December 2023, a retrospective analysis was performed on patient records within the Department of Spinal Surgery at Guilin People's Hospital. The analysis included comprehensive data on patients with presumed spinal infectious diseases, incorporating results from mNGS tests conducted externally, conventional pathogen detection results, laboratory examination results, and imaging findings. The study aimed to assess the applicability of mNGS in the context of suspected spinal infectious lesions.

RESULTS

Twenty-seven patients were included in the final analysis. Pathogenic microorganisms were identified in 23 cases. The included cases encompassed 1 case of tuberculous spondylitis, 1 case of fungal infection, 3 cases of Brucella spondylitis, 3 cases of viral infection, 9 cases of bacterial infection, and 6 cases of mixed infections. Pathogenic microorganisms remained elusive in 4 cases. The application of the mNGS method demonstrated a significantly elevated positive detection rate compared to conventional methods (85.19% vs. 48.15%, P < 0.05). Moreover, the mNGS method detected a greater variety of pathogen species than traditional methods (Z = 10.69, P < 0.05). Additionally, the mNGS method exhibited a shorter detection time.

CONCLUSIONS

mNGS demonstrated significantly higher detection rates for bacterial, fungal, viral, and mixed infections in cases of suspected spinal infectious diseases. The clinical implementation of mNGS could further enhance the efficiency of diagnosing and treating suspected spinal infectious diseases.

Trends in infectious spondylitis from 2000 to 2020

PURPOSE

This study aimed to investigate the trends in infectious spondylitis over the past two decades.

METHODS

We included 157 cases, from 2000 to 2020, of infectious spondylitis. The cases were divided into two groups: 00 (cases during 2000-2009; 82 cases:) and 10 (cases during 2010-2020; 75 cases) groups. Patients' age, sex, causative organism, and localization were examined and compared between the two groups.

RESULTS

The proportions of women in the 00 and 10 groups were 30.5% and 38.7%, respectively, with no significant difference (P = 0.28). The average age was significantly higher in the 10 group (72.6 years) than in the 00 group (68.8 years; P < 0.01). A compromised host was the cause of infection in 52.4% and 36.0% of the patients in the 00 and 10 groups, respectively, showing a significant difference. The bacterial identification rates were 70.1% and 77.3% in the 00 and 10 groups, respectively (P < 0.01), and the genus Staphylococcus was the most common bacteria. The proportions of resistant bacteria such as methicillin-resistant Staphylococcus aureus in the 00 and 10 groups were 27.3% and 6.7%, respectively (P < 0.01). Conversely, infectious diseases caused by indigenous bacteria in the oral cavity and intestines were more common in the 10group (37.8%) than in the 00 group (13.0%), showing a significant difference (P < 0.01).

CONCLUSION

Recently, infections caused by indigenous bacteria in the oral cavity and intestines have increased more than those caused by resistant bacteria over the past two decade.

Thoracic spine infection caused by Pseudomonas fluorescens: A case report and review of literature

BACKGROUND

The clinical incidence of spinal infection is gradually increasing, and its onset is insidious, easily leading to missed diagnosis and misdiagnosis, which may lead to serious complications such as nervous system dysfunction, spinal instability and/or deformity, and cause a huge burden on society and families. Early identification of the causative agent and precision medicine will greatly reduce the suffering of patients. At present, the main pathogenic bacteria that cause spinal infection are Staphylococcus aureus, Streptococcus, Pneumococcus, Escherichia coli, and Klebsiella. There are no reports of spinal infection caused by Pseudomonas fluorescens.

CASE SUMMARY

We report a 32-year-old female patient with spinal infection. She presented with flank pain, initially thought to be bone metastases or bone tuberculosis, and had a family background of tumors. Her clinical features and changes in imaging and laboratory tests led to the suspicion of thoracic spine infection. Histopathology of the lesion showed inflammation, tissue culture of the lesion was negative several times, and the possible pathogen - Pseudomonas fluorescens was found after gene sequencing of the lesion. The patient recovered completely after a full course of antibiotic treatment.

CONCLUSION

This report increases the range of pathogens involved in spinal infections, highlights the unique advantages of gene sequencing technology in difficult-to-diagnose diseases, and validates conservative treatment with a full course of antibiotics for spinal infections without complications.

Spinal infection after vertebral augmentation: a covert complication with serious havoc

INTRODUCTION

Vertebral augmentation, including percutaneous vertebroplasty (PVP) or kyphoplasty (PKP), is the current least invasive surgical option and has been widely used to treat the painful osteoporotic vertebral compression fractures (OVCF). However, the postoperative infections could be life-threatening, even though they rarely occur. Our studies aim to clarify the causation and outcomes of spinal infections following augmentation and meanwhile to identify the risk factors.

METHODS

A retrospective study was conducted on patients with OVCF who underwent PVP or PKP, and were subsequently admitted to our institution with postoperative spinal infection between January 2010 and December 2022. A total of 33 patients were finally included.

RESULTS

The rate of spinal infection after augmentation in our single institute was 0.05% (2/3893). In addition to these 2 patients, the remaining 31 were referred from other hospitals. All 33 patients exhibited elevated inflammatory parameters, 14 patients presented with fever, and 9 patients experienced neurological deficits. Additionally, 29 patients had comorbidity and risk factors. Pathogens were identified in 26 patients, while only 7 patients were examined as culture negative. 27 patients underwent revision surgery and 6 patients only received conservative therapy. Anterior surgery was performed in 2 patients, while posterior surgery was performed in 20 patients. A combined anterior-posterior surgery was performed in 5 patients. At the final follow-up, 18 patients had unrestricted mobility, 10 patients required assistance from crutches or a walker for ambulation, 4 patients needed a wheelchair, and 1 patients died after revision surgery.

CONCLUSIONS

Spinal infection after vertebral augmentation is rare, but it cannot be ignored. Surgeons should make every effort to detect the potential preoperative spondylitis or discitis. Once postoperative spinal infection is confirmed, a prompt intravenous antibiotic therapy is warranted. If medication therapy fails, revision surgery involving debridement and spinal reconstruction should be considered.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Surgical strategies for spinal infections: A narrative review

The successful operative management of spinal infections necessitates a thoughtful approach. Ideal treatment combines the universal goals of any spine operation, which are decompression of the neural elements and stabilization of instability, with source control and eradication of infection. Techniques to treat infection have evolved independently and alongside advances in implant technology and surgical techniques. This review will seek to outline current thinking on approaches to both primary and secondary spinal infections.

Single- and Multilevel Corpectomy and Vertebral body replacement for treatment of spinal infections. A retrospective single-center study of 100 cases

Background

The optimal operative approach for treating spinal infections remains a subject of debate. Corpectomy and Vertebral Body Replacement (VBR) have emerged as common modalities, yet data on their feasibility and complication profiles are limited.

Methods

This retrospective single-center study examined 100 consecutive cases (2015-2022) that underwent VBR for spinal infection treatment. A comparison between Single-level-VBR and Multi-level-VBR was performed, evaluating patient profiles, revision rates, and outcomes.

Results

Among 360 cases treated for spinal infections, 100 underwent VBR, located in all spinal regions. Average clinical and radiologic follow-up spanned 1.5 years. Single-level-VBR was performed in 60 cases, Two-level-VBR in 37, Three-level-VBR in 2, and Four-level-VBR in one case.Mean overall sagittal correction reached 10° (range 0-54°), varying by region. Revision surgery was required in 31 cases. Aseptic mechanical complications (8% pedicle screw loosening, 3% cage subsidence, 6% aseptic adjacent disc disease) were prominent reasons for revision. Longer posterior constructs (>4 levels) had significantly higher revision rates (p < 0.01). General complications (wound healing, hematoma) followed, along with infection relapse and adjacent disc infection (9%) and neurologic impairment (1%).Multilevel-VBR (≥2 levels) displayed no elevated cage subsidence rate compared to Single-level-VBR. Three deaths occurred (43-86 days post-op), all in the Multi-level-VBR group.

Conclusion

This study, reporting the largest number of VBR cases for spinal infection treatment, affirmed VBR's effectiveness in sagittal imbalance correction. The overall survival was high, while reinfection rates matched other surgical studies. Anterior procedures have minimal implant related risks, but extended dorsal instrumentation elevates revision surgery likelihood.

Predictors of conversion surgery after conservative treatment for pyogenic spondylitis

BACKGROUND

Patient demographic and clinical characteristics may be factors associated with the success of conservative treatment for pyogenic spondylitis. The ability of imaging findings at initial diagnosis to predict patient outcomes remains unclear. The aim of this study was to investigate the risk factors associated with conversion surgery after conservative treatment for pyogenic spondylitis, with a special focus on the initial computed tomography (CT) findings.

METHODS

This study enrolled 35 patients with pyogenic spondylitis who underwent CT and magnetic resonance imaging (MRI) at diagnosis and were followed-up for more than 6 months. Patients were diagnosed by MRI, and the degree of bone destruction was assessed on CT cross-sectional images. Vertebral body destruction was classified as grades 0 (almost normal), 1 (endplate irregularity), 2 (vertebral body destruction not involving the posterior wall), and 3 (destruction involving the posterior wall). Patients were divided into four groups based on grade of bone destruction and their clinical characteristics were compared.

RESULTS

1, 11, 11, and 12 patients were classified as grades 0, 1, 2, and 3, respectively. Univariate analysis showed no significant differences in the demographic and clinical characteristics of the four groups. Eighteen (51.4 %) patients had been treated surgically, with the rate of surgical treatment being significantly higher in patients with grade 3 (83.3 %) than in those with grades 0 + 1 (25 %) and grade 2 (45.5 %) (P < 0.05). Multivariate analysis showed that epidural abscess on MRI (odds ratio [OR] 10.8, 95 % confidence interval [CI] 1.68-69.7), grade 3 bone destruction on CT (OR 3.97, 95 % CI 1.21-13.0), and C-reactive protein (CRP) improvement rate after 1 week of treatment (OR 0.95, 95 % CI 0.91-0.99) were risk factors for surgery.

CONCLUSIONS

Early surgical treatment should be considered for patients with pyogenic spondylitis who present with an epidural abscess on MRI and bone destruction extending to the posterior wall on CT at the time of diagnosis.

Mixed pyogenic and tuberculous spinal epidural abscesses perforating the dura and extending into the subdural space: A case report and review of the literature

Background

Spinal infections are associated with a wide variety of clinical conditions, including osteomyelitis, spondylitis, diskitis, septic facet joints, and abscesses. Based on its anatomical relationship with the dura mater, the abscess can be epidural (extradural) or subdural (intrathecal). Subdural intramedullary abscesses of the lumbar spinal canal are more common than subdural extramedullary abscesses. Here, we present a rare case of a patient with a mixed pyogenic and tuberculous epidural abscess in the lumbar spine, which perforated the dura and extended to the subdural space.

Case Description

A 29-year-old male presented with progressively worsening back pain and lower-limb weakness over a period of 3 months, with an associated inability to walk, intermittent radicular pain primarily on the left side, intermittent incontinence, and a history of low-grade fever and night sweats. The patient had a history of intravenous (IV) drug abuse and reported practicing unprotected sexual intercourse. Furthermore, the patient had recently came into contact with a person diagnosed with tuberculosis (TB). The patient was administered empirical broad-spectrum antibiotics and underwent emergent L4-L5 laminectomy and spinal abscess decompression. IV antibiotics were selected based on culture results, and anti-TB medications were started. Postoperatively, the patient demonstrated a remarkable lower-limb power improvement and radicular pain alleviation.

Conclusion

Spinal epidural abscess perforation of the dura and extension into the subdural space is extremely rare. Distinguishing between epidural and subdural abscesses radiologically is challenging. Multiple risk factors, such as unprotected sexual contact and IV drug misuse, may be associated with the development of polymicrobial abscesses in the lumbar spine. Careful anticipation, identification, and isolation of the causative micro-organisms can ensure effective antibacterial treatment. Early diagnosis, expeditious surgical decompression, and antibiotic treatment are associated with promising outcomes.

Epidural abscess secondary to Streptococcus pneumoniae. A case report and review of the literature

While spinal epidural abscess is a well described disease process, this condition is rarely caused by Streptococcus pneumoniae. This case describes a case of spinal epidural abscess secondary to S. pneumoniae in an otherwise healthy, immunocompetent 61-year-old female without a history of spinal procedures, obvious source of hematogenous seeding, or clear risk factors for invasive pneumococcal infection. She was treated with IV and oral antibiotic therapy and made a full recovery.

Surgical site infection in spinal surgery: a bibliometric analysis

BACKGROUND

Surgical site infection (SSI) is a common complication in spinal surgery that can significantly affect the patient's prognosis. Despite advances in surgical techniques and infection control measures, SSI remains a considerable concern for healthcare providers and patients alike. In recent years, there has been a steady increase in studies related to SSI in spine surgery, leading to the publication of numerous informative articles. However, the current state and trends of research in the field of spinal SSI remain unclear. This study aims to conduct a bibliometric analysis of SSI-related articles in spine surgery to identify research status and trends. Meanwhile, we identify the top 100 most cited articles for further analysis.

METHODS

We searched for all articles related to spinal SSI in the Web of Science Core Collection, recording the publication year, country, journal, institution, keywords, and citation frequency for further analysis. In addition, we identified and analyzed the top 100 most cited articles.

RESULTS

A total of 307 articles related to spinal SSI were identified. All of these articles were published between 2008 and 2022, with the number of publications showing an increasing trend over the years. The related articles originated from 37 countries, with the USA contributing the most (n = 138). The institution with the highest number of publications and citations was Johns Hopkins University (14 articles; 835 citations). Among the journals, Spine had the highest number of articles (n = 47). The prevention of spinal SSI has been a research hotspot in recent years. Among the top 100 most cited articles, the most common research theme was the risk factors associated with spinal SSI.

CONCLUSIONS

In recent years, research related to spinal SSI has attracted the attention of numerous clinicians and scholars. As the first bibliometric analysis of spinal SSI, our study aims to provide pragmatic guidance for clinicians to learn the research status and trends in this field and improve their vigilance toward SSI.

Hydatid disease of the brain and spine

Hydatid disease of the central nervous system is relatively rare and comprises about 2-3% of all the hydatid cyst cases reported in the world. Spinal hydatid disease is an even rarer entity. It is endemic in sheep and cattle-raising regions, seen mainly in Mediterranean countries including Turkey and Syria. Pediatric neurosurgeons in non-endemic countries face a challenge when they encounter children with hydatid cysts of the central nervous system, mostly due to lack of awareness and the ensuing diagnostic dilemmas. It is also a significant socioeconomic problem in developing countries, due to improper hygiene and lack of dedicated veterinary practice. The clinical features are largely nonspecific and very according to location and severity of disease. However, with the advent of advances in MR imaging, the diagnostic accuracy of hydatic disease involving the brain and spine has increased. Intact removal of the cyst/s, without causing any spillage, and appropriate antihelminthic therapy is the goal and key to cure and prevention of recurrence. In this manuscript, the current literature on hydatid cyst of the brain and spine is reviewed to better understand the epidemiology, pathophysiology, diagnostic accuracy, and advances in therapeutic options. A heightened clinical suspicion, awareness of MR imaging features, improved surgical strategies, and options for prevention are discussed.

Neisseria gonorrhoeae cervical spine epidural abscess requiring spinal decompression and instrumented fusion

Disseminated gonococcal infection (DGI) is an uncommon complication of Neisseria gonorrhoeae infection, and typically presents with either a triad of tenosynovitis, dermatitis and polyarthralgia, or with extra-axial large joint septic arthritis. Spinal epidural abscess is a rare manifestation of DGI, with only a few previously reported cases, none of which required placement of metalware into the infected space. Here we report a severe case of isolated N. gonorrhoeae cervical spine epidural abscess necessitating surgical source control (C7/T1 laminectomy and debridement) and metalware placement (C6-T2 posterior instrumented fusion). The case was successfully managed by a combination of surgical intervention followed by six weeks of predominantly oral, targeted antimicrobial therapy.

Spinal infection caused by Coxiella burnetii

BACKGROUND

Spinal infection caused by Coxiella burnetii is rare and difficult to diagnose. Here we reported a case of spinal infection from Coxiella burnetii detected by the metagenomic next-generation sequencing (mNGS).

CASE PRESENTATION

A 66-year-old male farmer with no medical history reported severe sharp low back pain, numbness and lower limb weakness for three years. Magnetic resonance imaging (MRI) revealed bone destruction and spinal cord compression within L1 and L2. mNGS testing showed that the inspected specimen collected from spinal lesion was detected positively for Coxiella burnetii. After receiving the combined treatment of antibiotic therapy and surgical intervention, the patient recovered well, and the sagittal MRI showed that vertebral edema signals disappeared and the graft of bone fused 16 months after surgery.

CONCLUSION

The mNGS may be benefit for early diagnosis and intervention of non-specific spinal infection, and future studies should validate its effectiveness for clinical use in spinal infections. Additionally, antibiotic therapy combined with surgical intervention plays an important role on the treatment of spinal infection caused by Coxiella burnetii.

Vertebral Candidiasis, the State of the Art: A Systematic Literature Review

OBJECTIVE

In recent years, Candida spondylodiscitis has represented an increasingly emerging disease in clinical practice. This condition requires long-term antibiotic therapy and sometimes surgical treatments. The main purpose of this study is to investigate the epidemiology, clinical and radiological aspects, treatment protocols, and outcomes of Candida-mediated vertebral osteomyelitis.

METHODS

A systematic review of the English literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.The research was conducted on Medline, Cochrane library, PubMed, and Scopus using as search terms "vertebral"; "spinal"; "infection"; "spondylodiscitis"; "discitis"; "osteomyelitis"; "Candida"; and "Candidosis." A case of vertebral candidiasis that was surgically managed was also reported.

RESULTS

In total, 88 articles were included in our systematic review. Including the reported case, our analysis covered 113 cases of vertebral candidiasis. Candida albicans was isolated in 64 cases (56.1%), Candida tropicalis in 21 (18.4%), Candida glabrata in 14 (12.3%), and Candida parapsilosis in five (4.4%). The mean duration of the follow-up was 395 days. Finally, 87 (82%) patients completely recovered, ten (9.4%) died, and nine (8.5%) reported sequelae.

CONCLUSION

This systematic review summarized the state of the art on vertebral candidiasis, describing data on its clinical features, diagnostic criteria and current limitations, and treatment alternatives and their outcomes.

Citrobacter koseri: A rare cause of an epidural spinal abscess

Background

Citrobacter koseri, a Gram-negative organism, rarely causes an epidural spinal abscess.

Case Description

A 50-year-old male presented with mild paraparesis attributed to an magnetic resonance (MR)-documented spinal epidural abscess (SEA) at the T10-level. Following surgical debridement, cultures grew C. koseri, a rare Gram-negative organism. The abscess was subsequently managed with a prolonged course of antibiotics resulting in complete symptom and MR-documented radiological resolution.

Conclusion

A 50-year-old male presented with a T10 SEA attributed to a rare Gram-negative organism, C. koseri. The abscess was appropriately managed with surgical decompression/debridement, followed by prolonged antibiotic therapy.

Management of deep surgical site infections of the spine: a Canadian nationwide survey

Background

Deep surgical site infections after spinal instrumentation represent a significant source of patient morbidity and poorer outcomes. Given lack of evidence or guidelines on the variety of procedural options in the management of deep spine surgical site infections, the purpose of this survey was to document and investigate the use of these techniques across Canada.

Methods

A 34-question survey evaluating surgical techniques for irrigation and debridement in postoperative thoracolumbar infection was distributed to Canadian adult spine surgeons. Results were analyzed qualitatively, and comparisons by specialty, years of training, and number of cases were completed using Fischer's exact tests. We defined consensus as >70% agreement.

Results

We received 53 responses (62% response rate) from a comprehensive sample of Canadian adult spine surgeons. There was a consensus to retain hardware (80%) and interbody implants (93%) in acute infection, to retain interbody implants in chronic/recurrent infection (71%), and application of topical antibiotics in recurrent infection (85%). There was consensus on the use of absorbable suture to close fascia in acute (83%) and chronic (87%) infection. Eighty-five percent of surgeons used nonabsorbable materials such as Nylon or staples for skin closure in chronic infection, however, there was no consensus in acute infection. Surgeons varied significantly in type, volume and pressure of fluids, adjuvant solvents, graft management, use of topical antibiotics acutely, and the use of negative pressure wound therapy. Partial hardware exchange was controversial. Additionally, specialty or surgeon experience had no impact on management strategy.

Conclusions

This survey demonstrates significant heterogeneity amongst Canadian adult spine surgeons regarding key steps in the surgical management of deep instrumented spine infection, concordant with scarce literature addressing these steps.

Red flags for spinal pain in patients diagnosed with spinal infection in Nigeria: A 10-year medical records review

BACKGROUND

Spinal infection is a diagnostic challenge, the personal and economic consequences of misdiagnosis can be significant resulting in paralysis and instability of the spine and can ultimately be fatal. To aid identification of those at risk of spinal infection, a better understanding of the red flags for spinal infection is needed.

OBJECTIVE

To better understand which red flags may help to identify spinal infection.

DESIGN

and Methods: A 10-year medical records review of red flags for spinal infection in Nigeria, using a bespoke data extraction tool. Univariable and multivariable logistic regression was used to identify the main independent predictors of spinal pain.

RESULTS

124,913 records were reviewed, 1,645 patients were diagnosed with spinal infection. 79% of patients presented with spinal pain Univariable analysis revealed nine factors (some centres, all age groups above 16 years, co-morbidities, environmental factors, history of TB, radicular pain, pins and needles, numbness and spine tenderness.) were associated with greater odds (OR = 1.77-21.7, p < 0.001), whilst four (some centres, fatigue, fever and myotomal weakness) were associated with lower odds (OR = 0.51-0.59) of spine pain. Six factors were included in the final multivariable model associated with higher odds of spine pain: age groups above 16 years (OR 2.57 to 5.33, p < 0.05), co-morbidity (OR = 1.68, p < 0.05), history of TB (OR = 3.02, p < 0.05), weight loss (OR = 1.75, p < 0.01), radicular pain (OR = 19.88, p < 0.001); spine tenderness (OR = 6.54, p < 0.001). Myotomal weakness (OR = 0.66, p < 0.05) and fatigue (OR = 0.50, p < 0.01) were associated with lower odds of spinal pain in the final model.

CONCLUSION

Using data from ten hospitals in Nigeria within a ten-year period, we have produced a shortlist of red flags that can inform clinical decision making about potential spinal infection.

A case report of Klebsiella aerogenes-caused lumbar spine infection identified by metagenome next-generation sequencing

BACKGROUND

The early clinical diagnosis of spinal infections in elderly patients with recessive or atypical symptoms is difficult. Klebsiella aerogenes is a common opportunistic bacterium that can infect the respiratory tract, urinary tract, and even the central nervous system. However, whether it can infect the lumbar spine has not been previously described.

CASE PRESENTATION

In this paper, we report the case of a 69-year-old female patient with osteoporosis who was initially diagnosed with hemolytic anemia. Later, she was diagnosed with K. aerogenes infection of the lumbar spine based on imaging combined with blood culture and metagenome next-generation sequencing (mNGS) detection. After precise medication, the lumbar degeneration was improved.

CONCLUSIONS

Bacterial infection should therefore be considered in cases of lumbar degenerative disease in middle-aged and elderly patients.

Association between interhospital transfer and increased in-hospital mortality in patients with spinal epidural abscesses

BACKGROUND CONTEXT

Spinal epidural abscess (SEA) is an uncommon yet serious infection, associated with significant morbidity and mortality. Patients diagnosed with SEA often require surgical interventions or critical care services that are not available at community hospitals and are therefore transferred to tertiary care centers. Little is known about the effects of interhospital transfer on acute outcomes for patients with SEA.

PURPOSE

To study the effects of interhospital transfer on acute outcomes for patients with SEA.

STUDY DESIGN

Cross sectional analysis using the 2009 to 2017 National Inpatient Sample (NIS).

PATIENT SAMPLE

Using the 2009 to 2017 NIS, we identified cases of SEA using ICD, Ninth, or Tenth Revision diagnosis codes 324.1 & G06.1.

OUTCOME MEASURES

Our primary endpoint was in hospital mortality.

METHODS

The association between interhospital transfer and inpatient mortality was assessed using multivariable logistic regression to adjust for potential covariates. Patient and hospital factors associated with interhospital transfer were assessed in a secondary analysis.

RESULTS

A total of 21.5% of patient with SEA were treated after transfer from another hospital. After adjusting for covariates, those who presented after transfer had higher odds of death during hospitalization (OR: 1.51, 95% CI 1.27-1.78, p<.001). Transferred patients were significantly more likely to live in rural communities (11.4 % vs. 5.3 % for nontransferred patients).

CONCLUSIONS

Interhospital transfer, which occurred more frequently in patients from rural hospitals, was associated with death even after controlling for disease severity. Addressing healthcare delivery disparities across the US, including across the rural-urban spectrum, will require better understanding of the observed increased mortality of interhospital transfer as a preventable source of in-hospital mortality for SEA.

Diagnostic yield of image-guided biopsy in patients with suspected infectious spondylodiscitis : a prospective study from a tuberculosis-endemic country

AIMS

The aims of this study were to determine the diagnostic yield of image-guided biopsy in providing a final diagnosis in patients with suspected infectious spondylodiscitis, to report the diagnostic accuracy of various microbiological tests and histological examinations in these patients, and to report the epidemiology of infectious spondylodiscitis from a country where tuberculosis (TB) is endemic, including the incidence of drug-resistant TB.

METHODS

A total of 284 patients with clinically and radiologically suspected infectious spondylodiscitis were prospectively recruited into the study. Image-guided biopsy of the vertebral lesion was performed and specimens were sent for various microbiological tests and histological examinations. The final diagnosis was determined using a composite reference standard based on clinical, radiological, serological, microbiological, and histological findings. The overall diagnostic yield of the biopsy, and that for each test, was calculated in light of the final diagnosis.

RESULTS

The final diagnosis was tuberculous spondylodiscitis in 250 patients (88%) and pyogenic spondylodiscitis in 22 (7.8%). Six (2.1%) had a noninfectious condition-mimicking infectious spondylodiscitis, and six (2.1%) had no definite diagnosis and improved without specific treatment. The diagnosis was made by image-guided biopsy in 152 patients (56%) with infectious spondylodiscitis. Biopsy was contributory in identifying 132/250 patients (53%) with tuberculous spondylodiscitis, and 20/22 patients (91%) with pyogenic spondylodiscitis. Histological examination was the most sensitive diagnostic modality, followed by Xpert MTB/RIF assay.

CONCLUSION

Image-guided biopsy has a reasonably high diagnostic yield in patients with suspected infectious spondylodiscitis. A combination of histological examination, Xpert MTB/RIF assay, bacterial culture, and sensitivity provides high diagnostic accuracy in a country in which TB is endemic. Cite this article: Bone Joint J 2022;104-B(1):120-126.

Pyogenic and Non-Pyogenic Spinal Infections: Diagnosis and Treatment

Spinal infection (SI) is an infection of vertebral bodies, intervening disc, and/or adjoining para-spinal tissue. It represents less than 10 % of all skeletal infections. There are numerous factors that predispose to developing a SI. Due to the low specificity of signs, delayed diagnosis is common. Hence, SI may be associated with poor outcomes. Diagnosis of SI must be supported by clinicopathological and radiological findings. MRI is a reliable modality of choice. Treatment options vary according to the site of the infection, disease progression, neurology, presence of instability, and general condition of the subject. Conservative treatment (orthosis/ bed-rest + antibiotics) is recommended during the early course with no/ lesser degree of neurological involvement and to medically unfit patients. Nevertheless, when conservative measures alone fail, surgical interventions must be considered. The use of concomitant antimicrobial drugs intravenously during initial duration followed by oral administration is a necessity. Controversies exist regarding the optimal duration of antimicrobial therapy, yet never given less than six weeks. Heterogeneity in clinical picture and associated co-morbidities with a range of treatment modalities are available; however, a common applicable guideline for SI does not exist. Managing SI must be tailored on a case-to-case basis.

The potential of metagenomic next-generation sequencing in diagnosis of spinal infection: a retrospective study

PURPOSE

Metagenomic next-generation sequencing (mNGS) is a new approach to identify the infecting organism in infectious diseases. Our aim was to evaluate the accuracy of mNGS in determining the etiology of spinal infection.

METHODS

In this retrospective study, patients who had a suspected spinal infection and underwent mNGS for diagnosis in our hospital were eligible for inclusion. Samples for mNGS, culture, and histopathological tests were collected surgically or with a CT-guided needle biopsy. Sensitivity and specificity were calculated for mNGS and culture test, using histopathological results as reference.

RESULTS

A total of 31 mNGS tests in 30 cases were included. Twenty-six cases were classified as infected, and four cases were considered aseptic. mNGS achieved a specificity of 75.0% [95% confidence interval (CI), 21.9% to 98.7%], sensitivity was 70.3% (95% CI, 49.7% to 85.5%). mNGS was more sensitive than culture at 14.8% (95% CI, 4.9% to 34.6%, P < 0.0001). However, the specificities of mNGS and culture were statistically similar.

CONCLUSION

We described here the power of mNGS in the etiological diagnosing of spinal infection. Our study opens the possibility for more extensive use of mNGS techniques in the identification of pathogens in patients with suspected spinal infection.

Lumbar infection caused by Mycobacterium paragordonae: A case report

BACKGROUND

Mycobacterium paragordonae (M. paragordonae), a slow-growing, acid-resistant mycobacterial species, was first isolated from the sputum of a lung infection patient in South Korea in 2014. Infections caused by M. paragordonae are rare.

CASE SUMMARY

Herein, we report the case of a 53-year-old patient who presented with fever and low back pain. Lumbar nuclear magnetic resonance imaging revealed the destruction of the lumbar vertebra with peripheral abscess formation. After anti-infective and diagnostic anti-tuberculosis treatment, the patient had no further fever, but the back pain was not relieved. Postoperatively, the necrotic material was sent for pathological examination, and all tests related to tuberculosis were negative, but pus culture suggested nontuberculous mycobacteria. The necrotic tissue specimens were subjected to metagenomic next-generation sequencing, which indicated the presence of M. paragordonae. Finally, the infecting pathogen was identified, and the treatment plan was adjusted. The patient was in good condition during the follow-up period.

CONCLUSION

M. paragordonae, a rare nontuberculous mycobacterium, can also cause spinal infections. In the clinic, it is necessary to identify nontuberculous mycobacteria for spinal infections similar to Mycobacterium tuberculosis.

Spontaneous spondylodiscitis and endocarditis: interdisciplinary experience from a tertiary institutional case series and proposal of a treatment algorithm

Previously, the simultaneous presence of endocarditis (IE) has been reported in 3–30% of spondylodiscitis cases. The specific implications on therapy and outcome of a simultaneous presence of both diseases are not yet fully evaluated. Therefore, the aim of this study was to investigate the influence of a simultaneously present endocarditis on the course of therapy and outcome of spondylodiscitis. A prospective database analysis of 328 patients diagnosed with spontaneous spondylodiscitis (S) using statistical analysis with propensity score matching was conducted. Thirty-six patients (11.0%) were diagnosed with concurrent endocarditis (SIE) by means of transoesophageal echocardiography. In our cohort, the average age was 65.82 ± 4.12 years and 64.9% of patients were male. The incidence of prior cardiac or renal disease was significantly higher in the SIE group (coronary heart disease SIE n = 13/36 vs. S n = 57/292, p < 0.05 and chronic heart failure n = 11/36 vs. S n = 41/292, p < 0.05, chronic renal failure SIE n = 14/36 vs. S n = 55/292, p < 0.05). Complex interdisciplinary coordination and diagnostics lead to a significant delay in surgical intervention (S = 4.5 ± 4.5 days vs. SIE = 8.9 ± 9.5 days, p < 0.05). Mortality did not show statistically significant differences: S (13.4%) and SIE (19.1%). Time to diagnosis and treatment is a key to efficient treatment and patient safety. In order to counteract delayed therapy, we developed a novel therapy algorithm based on the analysis of treatment processes of the SIE group. We propose a clear therapy pathway to avoid frequently observed pitfalls and delays in diagnosis to improve patient care and outcome.

Clinicoradiographic predictors of percutaneous bone biopsy results among patients with suspected thoracolumbar spine infection

BACKGROUND

Image-guided percutaneous thoracolumbar spine biopsy is frequently performed in the setting of suspected septic facet arthritis or discitis osteomyelitis (DOM). There are limited data regarding factors associated with a positive biopsy result among these patients.

MATERIALS AND METHODS

Patients with suspected DOM who underwent spine biopsy were identified. Samples yielding a positive culture and/or histopathology suggestive of acute osteomyelitis were considered positive. The associations between selected medical comorbidities, laboratory values, pre-biopsy antibiotic administration, imaging findings and biopsy results were investigated.

RESULTS

121 patients underwent percutaneous biopsy with 35.5% yielding positive results. Biopsy results showed no correlation with comorbidities. The only laboratory value that correlated with a positive biopsy yield was blood culture positivity (p = 0.03). The imaging findings that correlated with a positive biopsy yield were the presence of a paraspinal fluid collection or epidural abscess (p = 0.003 and 0.018, respectively). Sampling paraspinal fluid collections, when present, resulted in a higher rate of a positive biopsy yield compared to sampling of bone or disc (p = 0.006). Patients who received antibiotics had a higher rate of a positive biopsy yield (p = 0.014). In those with positive blood cultures, biopsy yielded the same antimicrobial susceptibility profile in 13/14 cases.

CONCLUSION

The presence of a paraspinal fluid collection or epidural abscess is correlated with positive biopsy yield, and paraspinal fluid collections should be targeted for biopsy. Other imaging findings did not correlate with biopsy yield. Biopsy may not offer additional information for patients with positive blood cultures.

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.

Bacterial adhesion characteristics on implant materials for intervertebral cages: titanium or PEEK for spinal infections?

PURPOSE

Surgical intervention with intercorporal stabilisation in spinal infections is increasingly needed. Our aim was to compare titanium and polyetheretherketon (PEEK) cages according to their adhesion characteristics of different bacteria species in vitro.

METHODS

Plates made from PEEK, polished titanium (Ti), two-surface-titanium (TiMe) (n = 2-3) and original PEEK and porous trabecular structured titanium (TiLi) interbody cages (n = 4) were inoculated in different bacterial solutions, S.aureus (MSSA, MRSA), S.epidermidis and E.coli. Growth characteristics were analysed. Biofilms and bacteria were visualised using confocal- and electron microscopy.

RESULTS

Quantitative adherence of MSSA, MRSA, S.epidermidis and E.coli to Ti, TiMe and PEEK plates were different, with polished titanium being mainly advantageous over PEEK and TiMe with significantly less counts of colony forming units (CFU) for MRSA after 56 h compared to TiMe and at 72 h compared to PEEK (p = 0.04 and p = 0.005). For MSSA, more adherent bacteria were detected on PEEK than on TiMe at 32 h (p = 0.02). For PEEK and TiLi cages, significant differences were found after 8 and 72 h for S.epidermidis (p = 0.02 and p = 0.008) and after 72 h for MSSA (p = 0.002) with higher bacterial counts on PEEK, whereas E.coli showed more CFU on TiLi than PEEK (p = 0.05). Electron microscopy demonstrated enhanced adhesion in transition areas.

CONCLUSION

For S.epidermidis, MSSA and MRSA PEEK cages showed a higher adherence in terms of CFU count, whereas for E.coli PEEK seemed to be advantageous. Electron microscopic visualisation shows that bacteria did not adhere at the titanium mesh structure, but at the border zones of polished material to rougher parts.

Posterior stabilisation without formal debridement for the treatment of non-tuberculous pyogenic spinal infection in frail and debilitated population - A systematic review and meta-analysis

Non-tuberculous pyogenic spinal infection (PSI) incorporates a variety of different clinical conditions. Surgical interventions may be necessary for severe cases where there is evidence of spinal instability or neurological compromise. The primary surgical procedure, for late-stage PSI, focuses on the anterior approach with aggressive debridement of the infected tissue regions. An alternative treatment method that employs a posterior approach without any formal debridement, is seen as controversial. To the best of our knowledge, few case series and no systematic reviews are assessing the value of this posterior technique. We aim to evaluate the effectiveness of the posterior approach without formal debridement and the associated clinical outcomes, for PSI cases requiring surgical intervention. Several databases including MEDLINE, NHS Evidence, and the Cochrane database were searched from the date of creation of each database to December 16, 2019. A selection of the keywords used includes: "posterior approach", "debridement" and "discitis". Studies were excluded if they involved the anterior approach, carried out formal debridement, or were tuberculous spinal infection cases. We accepted any study type which included adult patients, with spinal infection at any level of the vertebral column. The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were used to follow standard systematic review structure. The main clinical outcomes evaluated include pain, neurological recovery (Frankel Grading System, FGS) post-operative complications, and functional outcomes (Kirkaldy-Willis Criteria and Spine Tango Combined Outcome Measure Index, COMI). Post-surgical neurological improvement was demonstrated with a mean FGS improvement of 1.12 in 102 patients over the included four articles. Post-operative neurological function was found to be improved at a statistically significant level when a random-effects model was applied, with the effect size found to be at 0.68 (p < 0.001). Pain level was improved significantly postoperatively. There were also enhanced functional outcomes post-intervention when the Kirkaldy-Willis criteria and COMI scores were assessed in certain studies. Within the limit of the available literature, our results showed that the posterior approach with posterior stabilisation without formal debridement can result in successful infection resolution, improved pain scores and neurological outcomes. However, Larger series with longer follow-up duration is strongly recommended.

Early surgery may lower mortality in patients suffering from severe spinal infection

PURPOSE

Spinal infection (SI) is a life-threatening condition and treatment remains challenging. Numerous factors influence the outcome of SI and both conservative and operative care can be applied. As SI is associated with mortality rates between 2 and 20% even in developed countries, the purpose of the present study was to investigate the occurrence and causes of death in patients suffering from SI.

METHODS

A retrospective analysis was performed on 197 patients, categorized into two groups according to their outcome: D (death) and S (survival). The diagnosis was based on clinical and imaging (MRI) findings. Data collected included demographics, clinical characteristics, comorbidities, infection parameters, treatment details, outcomes, and causes of death.

RESULTS

The number of deaths was significantly higher in the conservative group (n = 9/51, 18%) compared with the operative counterpart (n = 8/146, 6%; p = 0.017). Death caused by septic multiorgan failure was the major cause of fatalities (n = 10/17, 59%) followed by death due to cardiopulmonary reasons (n = 4/17, 24%). The most frequent indication for conservative treatment in patients of group D included "highest perioperative risk" (n = 5/17, 29%).

CONCLUSION

We could demonstrate a significantly higher mortality rate in patients solely receiving conservative treatment. Mortality is associated with number and type of comorbidities, but also tends to be correlated with primarily acquired infection. As causes of death are predominantly associated with a septic patient state or progression of disease, our data may call for an earlier and more aggressive treatment. Nevertheless, prospective clinical trials will be mandatory to better understand the pathogenesis and course of spinal infection, and to develop high quality, evidence-based treatment recommendations.

Diagnosing and treating native spinal and pelvic osteomyelitis in adolescents

STUDY DESIGN

Retrospective case series.

OBJECTIVES

To describe how pediatric patients with spinal and pelvic osteomyelitis are diagnosed and treated and assess the diagnostic value of magnetic resonance imaging (MRI), needle aspiration biopsy (NAB), and blood cultures in this population. Spinal and pelvic osteomyelitis de novo are uncommon in children and minimal literature exists on the subject. Research has shown that NAB and blood cultures have variable diagnostic yield in adult native osteomyelitis. At our institution, there is no standard protocol for diagnosing and treating pediatric spinal and pelvic osteomyelitis de novo.

METHODS

All diagnoses of spinal and pelvic osteomyelitis at a pediatric tertiary care center from 2003 to 2017 were reviewed. Patients aged 0-21 at diagnosis were included. Patients with osteomyelitis resulting from prior spinal operations, wounds, or infections and those with chronic recurrent multifocal osteomyelitis were eliminated. All eligible patients' diagnoses were confirmed by MRI.

RESULTS

29 patients (18 men, 11 women) met the inclusion criteria. The median age at diagnosis was 11 years old (range 1-18). More than half of all cases (17/29, 59%) affected the lumbar spine. The most common symptoms were back pain (20/29, 69%), fever (18/29, 62%), hip pain (11/29, 38%), and leg pain (8/29, 28%). The majority of NABs and blood cultures performed were negative, but of the positive tests Staphylococcus aureus was the most prevalent bacteria. 86% (25/29) had an MRI before a diagnosis was made and 72% (13/18) had an NAB performed post-diagnosis.

CONCLUSIONS

MRI is a popular and helpful tool in diagnosing spinal osteomyelitis de novo. NAB cultures are often negative but can be useful in determining antibiotic treatment.

LEVEL OF EVIDENCE

Level IV.

Spinal epidural abscess in COVID-19 patients

Objective

To report the peculiarity of spinal epidural abscess in COVID-19 patients, as we have observed an unusually high number of these patients following the outbreak of SARS-Corona Virus-2.

Methods

We reviewed the clinical documentation of six consecutive COVID-19 patients with primary spinal epidural abscess that we surgically managed over a 2-month period. These cases were analyzed for what concerns both the viral infection and the spinal abscess.

Results

The abscesses were primary in all cases indicating that no evident infective source was found. A primary abscess represents the rarest form of spinal epidural abscess, which is usually secondary to invasive procedures or spread from adjacent infective sites, such as spondylodiscitis, generally occurring in patients with diabetes, obesity, cancer, or other chronic diseases.

In all cases, there was mild lymphopenia but the spinal abscess occurred regardless of the severity of the viral disease, immunologic state, or presence of bacteremia. Obesity was the only risk factor and was reported in two patients. All patients but one were hypertensive. The preferred localizations were cervical and thoracic, whereas classic abscess generally occur at the lumbar level. No patient had a history of pyogenic infection, even though previous asymptomatic bacterial contaminations were reported in three cases.

Conclusion

We wonder about the concentration of this uncommon disease in such a short period. To our knowledge, cases of spinal epidural abscess in COVID-19 patients have not been reported to date. We hypothesize that, in our patients, the spinal infection could have depended on the coexistence of an initially asymptomatic bacterial contamination. The well-known COVID-19-related endotheliitis might have created the conditions for retrograde bacterial invasion to the correspondent spinal epidural space.

Furthermore, spinal epidural abscess carries a significantly high morbidity and mortality. It is difficult to diagnose, especially in compromised COVID-19 patients but should be kept in mind as early diagnosis and treatment are crucial.

All that glitters is not gold: A spinal epidural empyema following epidural steroid injection

Background:

Therapeutic epidural spinal injections (ESIs) of steroids are one of the most common nonsurgical management modalities employed for alleviating pain due to chronic persistent lumbar spinal disease. However, it is well documented that they have significant risks and complications without any long-term efficacy. ESI may result in epidural empyema which may be difficult to diagnose with delays resulting in significant permanent neurological sequelae.

Case Description:

A 45-year-old female presented with a lumbar spinal epidural empyema after receiving ESI for low back and right leg pain due to a lumbar disc herniation. Laboratory studies showed elevations of multiple inflammatory markers, and the MR documented a significant lumbar epidural empyema contributing to significant thecal sac compression. Clinically, the patient had an acute cauda equina syndrome warranting emergency surgery consisting of a laminectomy for debridement/decompression followed by long-term antibiotic treatment.

Conclusion:

Epidural empyema is a major potential complication of lumbar ESI. Multiple markedly elevated inflammatory markers (WBC, ESR, CRP, and procalcitonin) and MRI evidence of an epidural empyema necessitates emergent surgical intervention to limit morbidity, neurological sequelae, and mortality.

De novo methicillin-resistant Staphylococcus aureus vs. methicillin-sensitive Staphylococcus aureus infections of the spine, similar clinical outcome, despite more severe presentation in surgical patients

Vertebral osteomyelitis (VO) is a severe infection of the vertebral body and the adjacent disc space, where Staphylococcus aureus is most commonly isolated. The objective of this retrospective study was to determine risk factors for and compare outcome differences between de novo methicillin-resistant Staphylococcus aureus (MRSA) VO and methicillin-sensitive Staphylococcus aureus (MSSA) VO. A retrospective cohort study was performed by review of the electronic medical records of 4541 consecutive spine surgery patients. Among these 37 underwent surgical treatment of de novo MRSA and MSSA spinal infections. Patient demographics, pre- and postoperative neurological status (ASIA impairment score), surgical treatment, inflammatory laboratory values, nutritional status, comorbidities, antibiotics, hospital stay, ICU stay, reoperation, readmission, and complications were collected. A minimum follow-up (FU) of 12 months was required. Among the 37 patients with de novo VO, 19 were MRSA and 18 were MSSA. Mean age was 52.4 and 52.9 years in the MRSA and MSSA groups, respectively. Neurological deficits were found in 53% of patients with MRSA infection and in 17% of the patients with MSSA infection, which was statistically significant (p < 0.05). Chronic renal insufficiency and malnutrition were found to be significant risk factors for MRSA VO. Preoperative albumin was significantly lower in the MRSA group (p < 0.05). Patients suffering from spinal infection with chronic renal insufficiency and malnutrition should be watched more carefully for MRSA. The MRSA group did not show a significant difference with regard to final clinical outcome despite more severe presentation.

Topical vancomycin for treatment of methicillin-resistant Staphylococcus epidermidis infection in a rat spinal implant model

STUDY DESIGN

Basic science.

OBJECTIVE

Investigate the ability of local applicaiton of vancomycin, either in powder form or suspended within poly(lactic-co-glycolic acid) microspheres (MS), to treat infection using a rat spinal model. Surgical site infections (SSIs) are a serious complication after spine surgery and are associated with high morbidity and mortality and often caused my coagulase negative staphylococci. A comprehensive approach to reduce SSIs has been recommended including the use of topical vancomycin. Animal and human studies have shown improved control of infection with local compared to systemic antibiotics.

METHODS

K-wires seeded with methicillin-resistant Staphylococcus epidermidis RP62A (MRSE) were treated with vancomycin powder, carboxymethylcellulose sodium salt (CMC) (microsphere carrier), vancomycin powder, blank MS or vancomycin-loaded MS for 24 or 48 h in vitro after which bacteria were enumerated. In addition, a spinal instrumentation model was developed in rats with a bacterial seeded K-wire implanted into the right side of L4 and L5. Rats underwent no treatment or were treated locally with either vancomycin powder, blank MS or vancomycin-loaded MS. After 8 weeks, the K-wire, bone, soft tissue and wire fastener were cultured and results analyzed.

RESULTS

Vancomycin powder and vancomycin-loaded MS resulted in significantly fewer bacteria remaining in vitro than did CMC. Vancomycin powder- treated animals' cultures were significantly lower than all other groups (P < 0.0001) with negative culture results, except for one animal. The vancomycin-loaded MS-treated animals had lower bone bacterial counts than the controls (P < 0.0279); blank MS-treated animals had no differences in bacterial densities when compared to non-treated animals.

CONCLUSION

Vancomycin powder and vancomycin-loaded MS were active against MRSE in vitro, in a rat MRSE implant model; however, vancomycin MS were inferior to the topical vancomycin powder. Vancomycin powder prevented MRSE infection in a rat spinal implant infection model.

Rabbit model of Staphylococcus aureus implant-associated spinal infection

Post-surgical implant-associated spinal infection is a devastating complication commonly caused by Staphylococcus aureus. Biofilm formation is thought to reduce penetration of antibiotics and immune cells, contributing to chronic and difficult-to-treat infections. A rabbit model of a posterior-approach spinal surgery was created, in which bilateral titanium pedicle screws were interconnected by a plate at the level of lumbar vertebra L6 and inoculated with a methicillin-resistant S.aureus (MRSA) bioluminescent strain. In vivo whole-animal bioluminescence imaging (BLI) and ex vivo bacterial cultures demonstrated a peak in bacterial burden by day 14, when wound dehiscence occurred. Structures suggestive of biofilm, visualized by scanning electron microscopy, were evident up to 56 days following infection. Infection-induced inflammation and bone remodeling were also monitored using ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) and computed tomography (CT). PET imaging signals were noted in the soft tissue and bone surrounding the implanted materials. CT imaging demonstrated marked bone remodeling and a decrease in dense bone at the infection sites. This rabbit model of implant-associated spinal infection provides a valuable preclinical in vivo approach to investigate the pathogenesis of implant-associated spinal infections and to evaluate novel therapeutics.

Summary: A model of post-surgical methicillin-resistant Staphylococcus aureus implant-associated spinal infection was created in rabbits, recapitulating acute infection as well as chronic low-burden infection, with structures suggestive of biofilm formation and bone remodeling.

Implant-Associated Infection of Long-Segment Spinal Instrumentation: A Retrospective Analysis of 46 Consecutive Patients

Study Design

This single-center retrospective study analyzed patients with an implant-associated infection of spinal instrumentation (four or more segments) treated between 2010 and 2018.

Purpose

This study aimed to investigate the treatment of implant-associated infections of long-segment spinal instrumentation and to define risk factors for implant removal.

Overview of Literature

Implant-associated infection occurs in 0.7%–20% of spinal instrumentation. Significant blood loss, delayed reoperation, and use of effective antibiotics are reported risk factors for implant removal.

Methods

Patients with superficial infections not involving the implant were excluded. All patients received surgical and antibiotic treatments according to our interdisciplinary osteomyelitis board protocol. An infection was considered healed if a patient showed no signs of infection 1 year after termination of treatment. The patients were divided into an implant retention group and implant removal group, and their clinical and microbiological data were compared.

Results

Forty-six patients (27 women, 19 men) with an implant-associated infection of long-segment spinal instrumentation and mean age of 65.3±14.3 years (range, 22–89 years) were included. The mean length of the infected instrumentation was 6.5±2.4 segments (range, 4–13 segments). Implant retention was possible in 21 patients (45.7%); in the other 25 patients (54.3%), a part of or the entire implant required removal. Late infections were associated with implant removal, which correlated with longer hospitalization. Both groups showed high postoperative complication rates (50%) and high mortality rates (8.7%). In 39 patients (84.8%), infection was eradicated at a mean follow-up of 18.9±11.1 months (range, 12–60 months). Three patients (6.5%) were lost to follow-up.

Conclusions

Implant-associated infections of long-segment spinal instrumentations are associated with high complication and mortality rates. Late infections are associated with implant removal. Treatment should be interdisciplinary including orthopedic surgeons and clinical infectiologists.

Spinal epidural abscesses - The role for non-operative management: A systematic review

BACKGROUND

Spinal Epidural Abscesses (SEAs) are traditionally seen as a surgical emergency. However, SEAs can be discovered in entirely asymptomatic patients. This presents a dilemma for the attending clinician as to whether to subject these patients to significant surgery. This systematic review updates the evidence surrounding the efficacy of non-operative SEA management by means of intravenous antibiotics ± radiologically-guided aspiration.

AIMS

1. To assess failure rates of medical therapy for SEA. The absolute definition of 'failure' used by the study was recorded, and comparisons made. 2. To review of risk factors for success/failure of medical treatment for SEA.

METHODS

A database search with the MESH term 'epidural abscess' and keywords ['treatment' OR 'management'] were used.

RESULTS

14 studies were included. The number of SEA patients managed non-operatively ranged from 19 to 142. There was significant heterogeneity across the studies. Pooled Failure of Medical Therapy (FMT) (defined as any poor outcome) was 29.40%. When FMT = mortality the pooled rate was 11.49%. Commonly cited risk factors for FMT included acute neurological compromise, diabetes mellitus, increasing age and Staphylococcus aureus.

CONCLUSION

SEA will always be a condition mostly managed surgically. Despite this, there is growing evidence that non-operative management can be possible in the correct patients. The key is in patient selection - patients with any of the above-mentioned risk factors have the potential to deteriorate further on medical treatment and have a worse outcome than if they had undergone emergency surgery straight away. Ongoing research will hopefully further investigate this crucial step.

[Pyogenic spondylodiscitis: symptoms, diagnostics and therapeutic strategies]

BACKGROUND

Pyogenic spondylodiscitis is a rare disease that is being diagnosed with increasing frequency in recent years. It is associated with a high morbidity and mortality.

DIAGNOSIS

Often, because of its nonspecific symptoms, pyogenic spondylodiscitis is diagnose with some delay. In addition to pathogen detection, MRI is the gold standard to diagnose pyogenic spondylodiscitis. Also, x-ray imaging and CT can be carried out for surgical planning and for subsequent follow-up imaging. If blood or tissue cultures are negative, open surgical biopsies should be preferred over CT-guided biopsies.

THERAPY

The therapy can be conservative, such as immobilization, as well as antibiotics and analgesics, or surgical. If, for example, neurological deficits, spinale instabilities or deformities, septic disease progression or extensive abscess formations are present, surgical therapy is indicated. The surgical treatment strategies depend on the severity of the disease.

OUTLOOK

The prognosis is dependent on a rapid diagnosis and a swift start to therapy. There is no clear evidence with regard to treatment options (conservative vs. surgical therapy).

The clinical utility of fluoroscopic versus CT guided percutaneous transpedicular core needle biopsy for spinal infections and tumours: a randomized trial

BACKGROUND CONTEXT

Biopsy is important to obtain microbiological and histopathological diagnosis in spine infections and tumors. To date, there have been no prospective randomized trials comparing fluoroscopic guided and computed tomography (CT) transpedicular biopsy techniques. The goal of this study was to evaluate the accuracy, safety, and diagnostic outcome of these two diagnostic techniques.

PURPOSE

To evaluate the accuracy, safety, and diagnostic outcome of fluoroscopic guided and CT transpedicular biopsy techniques.

STUDY DESIGN

Prospective randomized trial.

PATIENT SAMPLE

Sixty consecutive patients with clinical symptoms and radiological features suggestive of spinal infection or malignancy were recruited and randomized into fluoroscopic or CT guided spinal biopsy groups. Both groups were similar in terms of patient demographics, distribution of spinal infections and malignancy cases, and the level of biopsies.

OUTCOME MEASURES

The primary outcome measure was diagnostic accuracy of both methods, determined based on true positive, true negative, false positive, and false negative biopsy findings. Secondary outcome measures included radiation exposure to patients and doctors, complications, and postbiopsy pain score.

METHODS

A transpedicular approach was performed with an 8G core biopsy needle. Specimens were sent for histopathological and microbiological examinations. Diagnosis was made based on biopsy results, clinical criteria and monitoring of disease progression during a 6-month follow up duration. Clinical criteria included presence of risk factors, level of inflammatory markers and magnetic resonance imaging findings. Radiation exposure to patients and doctors was measured with dosimeters.

RESULTS

There was no significant difference between the diagnostic accuracy of fluoroscopic and CT guided spinal biopsy (p=0.67) or between the diagnostic accuracy of spinal infection and spinal tumor in both groups (p=0.402 for fluoroscopy group and p=0.223 for CT group). Radiation exposure to patients was approximately 26 times higher in the CT group. Radiation exposure to doctors in the CT group was approximately 2 times higher compared to the fluoroscopic group if a lead shield was not used. Lead shields significantly reduced radiation exposure to doctors anywhere from 2 to 8 times. No complications were observed for either group and the differences in postbiopsy pain scores were not significant.

CONCLUSIONS

The accuracy, procedure time, complication rate and pain score for both groups were similar. However, radiation exposure to patients and doctors were significantly higher in the CT group without lead protection. With lead protection, radiation to doctors reduced significantly.

Comparative outcomes of operative relative to medical management of spondylodiscitis accounting for frailty status at presentation

PURPOSE

Investigate outcomes in a spondylodiscitis (SD) patient cohort undergoing operative and medical treatment or medical treatment alone, accounting for frailty status at presentation.

METHODS

Patients >18 years old undergoing treatment for SD were retrospectively analyzed. The diagnosis of SD was made through a combination of clinical findings, MRI/CT findings, and blood/tissue cultures. Those who failed to respond to antibiotics, had deteriorating markers, or developed neurologic compromise were considered operative candidates. Patients were stratified based on operative (Op, operative plus medical management) or conservative (Cons, medical only) treatment. Univariate analyses identified differences in outcome measures across treatment groups. Conditional forward regression equations, controlling for patient age, identified predictors of increased mortality and inferior outcomes.

RESULTS

116 patients with SD were included. 73 underwent Cons treatment and 43 were Op. Op patients were significantly younger (62.9vs70.7yrs; p < 0.001) and less frail (1.09vs1.85; p < 0.006) than Cons patients, with significantly higher WCC and ESR. Cons pts had higher rates of isolated SD, but Op pts had higher rates of SD with associated SEA, VOM, psoas abscess, and para-vertebral abscess (all p < 0.05). Op pts had significantly lower 30-day mortality than Cons pts (2.3%vs17.8%, p = 0.016), and trended lower 1Y mortality (11.6%vs20.5%, p = 0.310) with similar SD recurrence rates (11.6%vs16.4%, p = 0.592). Patients with an mFI > 3 had significantly higher 30-day mortality (30.4% vs 7.5%, p = 0.003) and trended higher 1-year mortality regardless of intervention.

CONCLUSIONS

Operative intervention was associated with lower 30-day mortality significantly and 1-year mortality compared to conservative treatment, while an increased mFI was associated with higher short-term mortality.

Percutaneous endoscopic debridement with percutaneous pedicle screw fixation for lumbar pyogenic spondylodiscitis: a preliminary study

PURPOSE

To access the feasibility and efficacy of percutaneous endoscopic debridement (PED) combined with percutaneous pedicle screw fixation (PPSF) in the treatment of lumbar pyogenic spondylodiscitis.

METHODS

Forty-five patients diagnosed as pyogenic spondylodiscitis underwent PPSF followed by PED. A drainage catheter was left in place for negative pressure drainage. Adequate systematic antibiotics were administered empirically or based on bacterial culture results. Clinical outcomes were assessed by physical examination, regular serologic testing, visual analog scale (VAS), Oswestry Disability Index (ODI), and imaging studies.

RESULTS

The mean operative time was 110.1 ± 21.2 minutes (range 80-165 minutes), with intra-operative blood loss 47.8 ± 21.0 ml (range 20-120 ml). All patients reported relief of back pain, able to sit up, and partially ambulate the next day. Causative pathogens were identified in 32 of 45 biopsy specimens, staphylococcal bacteria being the most prevalent strain. However, there were 13 patients with post-operative complications. During 6-12 months' follow-up, inflammatory markers showed infection controlled. VAS and ODI values were significantly improved.

DISCUSSION

Satisfactory clinical and functional outcomes were achieved in our patients post-operatively. It is recommended that PED plus PPSF can be another alternative for spondylodiscitis.

CONCLUSION

PED supplementing PPSF offers a valid option in treating spondylodiscitis, as it is minimally invasive, shortens hospital stay, and avoids prolonged bed rest with an optimistic outcome.

[Which factors influence the inpatient course for patients with spondylodiscitis?]

BACKGROUND

Spondylodiscitis is a rare disease with an increasing incidence.

METHODS

In this retrospective study 112 patients with spondylodiscitis surgically treated from 1 January 2005 to 31 December 2012 in a level I spine center were investigated with respect to potential prognostic criteria. The time period covered by the investigation was the duration of hospitalization. The parameters analyzed were mortality, age, localization of the spondylodiscitis, detection of abscesses and pathogens, neurological status and body mass index (BMI).

RESULTS

The average age of the patients was 68.3 years (±12.9 years). The mortality rate during hospitalization was 10.7% (N = 12). Older patients had a significantly higher in-hospital mortality rate (p = 0.008). Abscess formation was found in 49.1% of the patients and was associated with a significantly longer hospital stay (p = 0.001) and in the intensive care unit (ICU, p = 0.001) as well as a higher risk of revision surgery (p = 0.018). In addition, obese patients had a significantly higher occurrence of abscesses (p = 0.034). Pathogen detection was successful in 60.7 % of the cases with Staphylococcus aureus as the most frequent pathogen. Detection of pathogens was associated with a longer hospital stay (p = 0.006) and a greater need of intensive care monitoring (p = 0.017). Patients with a nephropathy had a significantly increased mortality, longer duration of hospitalization and a more frequent occurrence of multilevel afflictions.

CONCLUSION

Old age, abscess formation, positive detection of pathogens and renal failure can be used as prognostic criteria. Risk factors for formation of abscesses include a lumbar localization of spondylodiscitis, nephropathy as well as detection of a pathogen and obesity.

Short postsurgical antibiotic therapy for spinal infections: protocol of prospective, randomized, unblinded, noninferiority trials (SASI trials)

BACKGROUND

There are several open scientific questions regarding the optimal antibiotic treatment of spinal infections (SIs) with or without an implant. The duration of postsurgical antibiotic therapy is debated.

METHODS

We will perform two unblinded randomized controlled trials (RCTs). We hypothesize that shorter durations of systemic antibiotic therapy after surgery for SI are noninferior (10% margin, 80% power, α = 5%) to existing (long) treatment durations. The RCTs allocate the participants to two arms of 2 × 59 episodes each: 3 vs. 6 weeks of targeted postsurgical systemic antibiotic therapy for implant-free SIs or 6 vs. 12 weeks for implant-related SIs. This equals a total of 236 adult SI episodes (randomization scheme 1:1) with a minimal follow-up of 12 months. All participants receive concomitant multidisciplinary surgical, re-educational, internist, and infectious disease care. We will perform three interim analyses that are evaluated, in a blinded analysis, by an independent study data monitoring committee. Besides the primary outcome of remission, we will also assess adverse events of antibiotic therapy, changes of the patient's nutritional status, the influence of immune suppression, total costs, functional scores, and the timely evolution of the (surgical) wounds. We define infection as the presence of local signs of inflammation (pus, wound discharge, calor, and rubor) together with microbiological evidence of the same pathogen(s) in at least two intraoperative samples, and we define remission as the absence of clinical, laboratory, and/or radiological evidence of (former or new) infection.

DISCUSSION

Provided that there is adequate surgical debridement, both RCTs will potentially enable prescription of less antibiotics during the therapy of SI, with potentially less adverse events and reduced overall costs.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04048304. Registered on 5 August 2019.

PROTOCOL VERSION

2, 5 July 2019.

Clinical prevalence and population incidence of serious pathologies among patients undergoing magnetic resonance imaging for low back pain

BACKGROUND

In rare cases low back pain may be caused by underlying serious pathology such as fracture, malignancy, cauda equina syndrome, or spinal infection. The lack of evidence regarding either the clinical prevalence or population incidence of serious pathologies in the lumbar spine makes it difficult for clinicians to adequately assess a patient's risk of serious pathology.

PURPOSE

To determine the prevalence of serious pathologies in patients with low back pain who have been referred for a lumbar magnetic resonance imaging (MRI) by a specialist in a private secondary care or public tertiary care setting. The incidence of these serious pathologies in the geographic region of South Auckland, New Zealand was also investigated.

STUDY DESIGN

Retrospective, observational cohort study.

PATIENT SAMPLE

Consecutive patients referred for lumbar MRI over a 10-month period (1st of October 2013-31st of July 2014).

METHOD

Data from all eligible MRI reports was analyzed and any serious pathologies were identified and recorded. Prevalence (along with 95% confidence intervals) was calculated as a percentage of the study population. Prevalence specific to private secondary care and public tertiary care settings was also calculated and prevalence rate ratios were determined to allow comparison between settings. Incidence in the geographic region of South Auckland, New Zealand, was determined using data collected from participants recruited from the regional public hospital. Population incidence with respect to age, gender, and ethnicity for each target condition was calculated and incidence rate ratios were computed to compare groups.

RESULTS

A total of 2,383 participants referred for lumbar MRI scans were included in this study. Prevalence was significantly higher in the public tertiary care setting than in the private secondary care setting for all pathologies investigated in this study. Pathology specific prevalence in secondary care vs tertiary care settings was: malignancy, 0.3%, 4.4% (p<.001); fracture 2.2%, 6.7% (p<.001); cauda equina compression 0.6%, 2.3% (p=.001); infection 0.1%, 3.4% (p<.001). The combined prevalence in secondary care was 3.2% and in tertiary care 14.8% (p<.001). Pathology specific total incidence was: fracture, 13 per 100,000 person-years (p-y); malignancy 8.5 per 100,000 p-y; cauda equina compression 4.4 per 100,000 p-y; spinal infection 6.6 per 100,000 p-y.

CONCLUSIONS

The prevalence of serious pathologies was significantly higher in tertiary care (public health) than in private secondary care settings. One in every 6.5 patients referred for MRI in tertiary care demonstrated structural abnormalities associated with serious pathology, which raises the question of whether access to MRI should be re-evaluated.

Red flags for the early detection of spinal infection in back pain patients

BACKGROUND

Red flags are signs and symptoms that are possible indicators of serious spinal pathology. There is limited evidence or guidance on how red flags should be used in practice. Due to the lack of robust evidence for many red flags their use has been questioned. The aim was to conduct a systematic review specifically reporting on studies that evaluated the diagnostic accuracy of red flags for Spinal Infection in patients with low back pain.

METHODS

Searches were carried out to identify the literature from inception to March 2019. The databases searched were Medline, CINHAL Plus, Web of Science, Embase, Cochrane, Pedro, OpenGrey and Grey Literature Report. Two reviewers screened article texts, one reviewer extracted data and details of each study, a second reviewer independently checked a random sample of the data extracted.

RESULTS

Forty papers met the eligibility criteria. A total of 2224 cases of spinal infection were identified, of which 1385 (62%) were men and 773 (38%) were women mean age of 55 (± 8) years. In total there were 46 items, 23 determinants and 23 clinical features. Spinal pain (72%) and fever (55%) were the most common clinical features, Diabetes (18%) and IV drug use (9%) were the most occurring determinants. MRI was the most used radiological test and Staphylococcus aureus (27%), Mycobacterium tuberculosis (12%) were the most common microorganisms detected in cases.

CONCLUSION

The current evidence surrounding red flags for spinal infection remains small, it was not possible to assess the diagnostic accuracy of red flags for spinal infection, as such, a descriptive review reporting the characteristics of those presenting with spinal infection was carried out. In our review, spinal infection was common in those who had conditions associated with immunosuppression. Additionally, the most frequently reported clinical feature was the classic triad of spinal pain, fever and neurological dysfunction. This is an Open Access article distributed in accordance with the Creative Commons Attribution Non-Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

Spinal epidural abscess caused by Streptococcus agalactiae in an immunocompetent patient

BACKGROUND

Streptococcus agalactiae is an uncommon microorganism that causes spinal epidural abscess (SEA) and usually affects individuals with a predisposing condition or potential source of infection.

CASE DESCRIPTION

We present the case of an immunocompetent 53-year-old patient with an unremarkable past medical history who developed progressive low extremity weakness, bowel and bladder dysfunction and genital sensory impairment. A neurological exam on admission revealed flaccid proximal paraparesis, T10 sensory level, atonic anal sphincter and normal myotatic reflexes. Urgent neuroimaging showed a large thoracic epidural spinal abscess. Laminectomy and abscess drainage were immediately performed and systemic antibiotic treatment was initiated. Abscess cultures revealed Streptococcus agalactiae. After an exhaustive workup no predisposing factors or local or systemic source for the infection were found.

CONCLUSIONS

We report a singular case of spinal epidural abscess caused by Streptococcus agalactiae in a healthy patient with no predisposing factors. This case also highlights the importance of an early diagnosis and treatment to obtain a better neurological outcome.