Pyogenic Spine Infection Research Articles

The routine clinical use of fluorodeoxyglucose PET/CT to confirm treatment response in pyogenic spine infection.

Response of pyogenic spine infection to antibiotic therapy is usually based on nonspecific symptoms and inflammation markers. Abnormalities on MRI persist too long to influence therapy. Is FDG-PET/CT a timely and robust predictor of successful therapy? Retrospective study. Sequential FDG-PET/CTs done to assess treatment response over a 4-year period. Recurrence of infection after stopping treatment was the endpoint. One hundred seven patients enrolled. First treatment response scan showed no signs of infection in 69 patients (low risk). Twenty-four additional patients underwent additional treatment after an initial positive scan with low-risk pattern on follow-up imaging. After stopping antibiotics, none had clinical recurrence of infection. One had positive cultures at surgery for negative predictive value of 0.99. Thirty-eight patients had evidence of residual infection. Abnormalities in 28 were comparable to what is seen with untreated infection (high-risk). Twenty-seven received additional treatment until resolution. Antibiotics were stopped in 1 who suffered recurrence. Ten had low-grade/localized abnormalities consistent with infection (intermediate-risk). Signs of infection resolved in 3 after additional treatment. Of the remaining 7 patients who had minor residual abnormalities when antibiotics were stopped, 1 had recurrent infection for a positive predictive value of 0.14. Risk stratification proposed: A low-risk scan with only inflammation at a destroyed joint indicates negligible risk of recurrence. Unexplained activity in bone, soft tissue or spinal canal indicates high risk with further antibiotics recommended. Most patients with subtle or localized findings (intermediate risk) did not experience recurrence. Stopping therapy could be considered under careful observation.

The epidemiology of concurrent infection in patients with pyogenic spine infection and its association with early mortality: A nationwide cohort study based on 10,695 patients

BackgroundGenerally, a sufficient duration of relevant antibiotics based on an appropriate culture combined with proper surgical treatment guarantees a favorable clinical outcome in patients with pyogenic spine infections. However, a patient’s condition often deteriorates as concurrent infections occur in other organs, leading to mortality. Therefore, this study aimed to investigate the epidemiology of concurrent infections in patients with a pyogenic spine infection and estimate the rates and risks of early mortality. MethodsPatients with a pyogenic spine infection were identified using a national claims database that includes the entire population. The epidemiology of the six types of concurrent infections was investigated, and the corresponding early mortality rates and risks were estimated. The results were validated internally by bootstrapping and externally by defining two additional cohorts for sensitivity analysis. ResultsAmong 10,695 patients with a pyogenic spine infection, the prevalence of the six types of concurrent infections was 11.3 % for urinary tract infections, 9.4 % for intra-abdominal infections, 8.5 % for pneumonia, 4.6 % for septic arthritis or osteomyelitis of the extremities, 0.7 % for central nervous system infections, and 0.5 % for cardiac infections. Patients with a concurrent infection had approximately 4-fold greater mortality than those without (3.3 % vs. 0.8 %). The early mortality rates were particularly higher in patients with multiple or specific types of concurrent infections, including central nervous system infections, cardiac infections, and pneumonia. In addition, the mortality trends differed significantly according to the number and type of concurrent infections. ConclusionsThese data on six types of concurrent infection among patients with pyogenic spinal infection can be used as a source of reference by clinicians.

Analysis of Clinical Factors Associated with Medical Burden and Functional Status in Pyogenic Spine Infection

Pyogenic spinal infection (PSI) has recently been on the rise due to aging and increasing degenerative spinal disease related procedures. PSI requires long-term antibiotic treatment and is followed by sustained functional disability even after successful treatment. This study aimed to analyze the clinical factors associated with medical burden and functional status of PSI. This retrospective study involved patients with non-postoperative PSI of thoraco-lumbo-sacral area in a single tertiary hospital. The length/cost of hospitalization with an antibiotic therapy and severity of back pain using the short form 36 (SF-36) were defined as the medical burden and functional status, respectively. We analyzed the clinical factors associated with medical burden and functional status. We enrolled 142 patients (91 males and 51 females). The length and cost of hospitalization were 55.56 ± 27.09 (7-172) days and $14,070.17 ± 9289.39 (1611.87-48,722.35), respectively. A recurrence rate of 7.7% (11/142) and significant improvement of SF-36 at six months after completion of antibiotic treatment were noted (p < 0.05). Procedure-related (OR 2.702), C-reactive protein (CRP; OR 1.062), bacteremia (OR 4.966), additional surgical treatment (OR 6.524), recurrence (OR 12.453), and paraspinal abscess (OR 5.965) for above-average length of hospitalization were observed; female (OR 4.438), CRP (OR 1.071), bacteremia (OR 4.647), additional surgical treatment (OR 6.737), recurrence (OR 22.543), and extent of lesion (OR 1.431) for above-average cost of hospitalization; leg weakness (OR 15.966), white blood cell (WBC; OR 1.116), Charlson's comorbidity index (CCI, OR 1.485), and identification of causative bacteria (OR 2.913) for below-average initial SF-36 were observed; leg weakness (OR 7.975) and WBC (OR 1.094) for below-average 6-month SF-36 were the statistically significant clinical factors in the multivariable logistic regression analysis (p < 0.05). Recurrence and leg weakness were identified as the most important clinical factors for medical burden and functional status in PSI, respectively. We think that it is necessary to actively suppress recurrence and manage neurological deficits for decreasing medical burden and achieving favorable functional outcome in the treatment of PSI.

Trends and characteristics of primary pyogenic spine infections among people who do and do not inject drugs: Northeast New York State, 2007 to 2018

Background: Pyogenic spine infections (PSIs) are challenging to diagnose and treat. People who inject drugs (PWID) are at increased risk and contribute to rising PSI incidence. Objective: To analyze trends and characterize PSI in persons who do and do not inject drugs in northeast New York State (NYS), a predominantly rural region. Methods: A retrospective study of PSI patients at a regional tertiary care hospital from 2007 to 2018 was conducted. PSI incidence, population demographics, microbiology, surgical interventions, length of stay (LOS), and costs were compared between injection substance use disorder (ISUD) and non-ISUD cohorts. Results: Two hundred and seventy patients (59 ISUD and 211 non-ISUD) were included in this study. PSI incidence due to ISUD increased 1175% during the study time periods. The median age of the ISUD and non-ISUD cohorts was 39 and 65, respectively. Staphylococcus aureus was the most common causative organism, although a variety of bacterial and fungal pathogens were identified. Nearly half of the patients in each cohort required surgical intervention. Median acute care LOS was 12 days and comparable between cohorts. However, the ISUD cohort was frequently discharged against medical advice, or transferred back to acute care hospitals to complete antibiotic courses. Median inpatient hospital costs were approximately $25,000 and were comparable between cohorts. These costs do not reflect inpatient costs once the patient was transferred back to the referring hospital, nor costs for outpatient care. Medicaid and Medicare were the most common primary insurance payers for the ISUD and non-ISUD cohorts, respectively. Conclusions: Incidence of PSI has increased significantly coincident with the opioid epidemic and has had significant impact on a large, rural region of NYS. PSIs consume large amounts of healthcare resources. This study can inform hospitals and public health agencies regarding the need for substance abuse harm reduction strategies.

Diagnostic challenges in pyogenic spinal infection: an expanded role for FDG-PET/CT.

In a preliminary investigation of FDG-PET/CT for assessment of therapy response of pyogenic spine infection, it was concluded that activity confined to the margins of a destroyed or degenerated joint with bone-on-bone contact represents nonseptic inflammation, regardless of the intensity of uptake. Only activity in bone, soft tissue, or within the epidural space represents active infection. The purpose of this investigation was to assess the performance of these pattern-based interpretation criteria in a series of problem cases of proven or suspected spine infection. Eighty-two FDG-PET/CTs were done for initial diagnosis because other imaging failed to provide a definitive diagnosis and 147 FDG-PET/CTs were done to assess treatment responses. Pattern-based interpretations were compared with the clinical diagnosis based on bacterial cultures and outcomes after cessation or withholding of antibiotic therapy. Pattern-based interpretation criteria achieved a sensitivity and specificity of 98 and 100%, respectively, for initial diagnosis and a specificity of 100% for assessment of treatment response. The same data was analyzed using intensity of activity as the primary factor. Sensitivity and specificity using the intensity-based criteria were 93 and 68%, respectively, for initial diagnosis, and the specificity of a negative interpretation for therapy response was 55%. Differences from pattern-based criteria are highly significant. Pattern-based criteria perform well in problem cases with equivocal MR and for treatment response because they correctly eliminate activity from nonspecific inflammation associated with destroyed joints with bone-on-bone contact. Response occurs within a timeframe that is useful for managing antibiotic therapy.

Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Interpretation Criteria for Assessment of Antibiotic Treatment Response in Pyogenic Spine Infection

PurposeThe objective of the study was to determine if fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) can assess the response of patients with pyogenic spine infection to antibiotic treatment in a clinically useful time frame. MethodsTwenty-eight patients with suspected pyogenic spine infection had baseline 18F-FDG PET/CT. Patients with proven or probable infection were divided into good and poor responders to antibiotic therapy based on clinical criteria. These patients had a follow-up 18F-FDG PET/CT 6-8 weeks later. ResultsSix of 28 patients were deemed negative for infection based on 18F-FDG PET/CT. Two patients were excluded because of discrepancies in interpretation. Of the 20 patients deemed positive for infection, 13 had a pathogen isolated and all showed 18F-FDG uptake in bone and/or soft tissue at baseline. Patients with a poor clinical response to treatment had persistent 18F-FDG uptake in bone and/or soft tissue on follow-up. Patients with good clinical response had uptake confined to the margins of the destroyed disc. None of these patients had recurrent infection, even if antibiotics had already been discontinued at the time of the follow-up scan. Conclusions18F-FDG uptake confined to the margins of a destroyed disc after antibiotic therapy of pyogenic spine infection must not be considered indicative of persistent infection and likely represents mechanically induced inflammation. 18F-FDG uptake in bone or soft tissue does indicate active infection. Quantification of activity could not reliably differentiate patients with active infection from those without active infection and those who had had a successful response to therapy. The pattern of activity is critical to accurate interpretation.

Diagnosis and management of primary pyogenic spinal infections in intravenous recreational drug users.

Primary spine infection secondary to intravenous drug abuse (IVDA) is a difficult clinical entity encountered by spine surgeons and infectious disease specialists. Patients tend to be noncompliant with the treatment and follow-up, and some continue to use IV recreational drugs even after the diagnosis of spine infection. The authors undertook this study to analyze the presentation, etiology, demographic characteristics, treatment, and outcome of primary pyogenic spinal infection in patients with IVDA as the major risk factor. The medical records, radiology imaging, and laboratory results (white blood cell count, inflammatory markers, bacteriology cultures) of all patients with pyogenic spine infection and history of IVDA presenting to a tertiary care center from August 2005 through December 2013 were retrospectively reviewed. The department of neurosurgery database and the hospital electronic medical records of University Hospital in San Antonio were used to identify the cohort for our study. A total of 164 patients with spinal infection were evaluated during the study period; 102 of these patients had a history of IVDA. Their average age was 45.4 years, and only 14 (13.7%) were women. The mean laboratory values at presentation included a white blood cell count of 11.1 × 10(3) cells/μl (range 0.5-32 × 10(3) cells/μl), erythrocyte sedimentation rate (ESR) of 74 mm/hr (range 9.9-140 mm/hr), and C-reactive protein (CRP) level of 67 mg/L (range 0.1-327 mg/L). Twenty-six patients (25.4%) had an associated epidural abscess. The most common organism isolated from cultures of the bone and/or blood was methicillin-sensitive Staphylococcus aureus (MSSA), which was found in 37 cases. A close second was methicillin-resistant S. aureus (MRSA), found in 23 cases. The most commonly involved region was the lumbar spine (24 cases [57.8%]), and most patients (69.6%) had involvement of only a single level. Eighty patients were initially treated with long-term IV antibiotic therapy, and only 22 underwent surgical intervention (24 procedures). Of the latter group, 8 patients underwent laminectomy alone while 16 required some type of instrumented stabilization. Of the patients requiring stabilization procedures, 2 (12.5%) required reoperation with extension of their surgical constructs to other levels. The average follow-up was 29.7 weeks (range 6 weeks to 3 years). Diagnosis and management of spinal infection in patients with a history of IVDA is challenging. The data from this study show that initial laboratory values are difficult to interpret given that only a minority of these patients present with leukocytosis. Back pain was the only reliable predictor of spine infection. The authors' experience indicates that the majority of patients with spine infection and a history of IVDA can be successfully treated with IV antibiotic therapy alone.

Disseminated Septic Emboli, Septic Thrombosis of the Vena Cava and the Common Iliac and Renal Veins, and Retroperitoneal Abscess Secondary to Pyogenic Spondylitis of the Lumbar Spine

Pyogenic spondylitis is an infection of the spine that can include the disc, bone, the epidural space, and adjacent structures1,2. With adequate clinical suspicion and appropriate diagnostic evaluation, most pyogenic spine infections can be managed with culture-specific antibiotics2,3. However, in certain cases, surgery may be necessary to perform an open biopsy or treat a clinically relevant abscess, spinal instability, a severe deformity, or a neurologic deficit; surgery may also be necessary because of the failure of nonoperative treatment1-3. Septic thrombosis of the vena cava is a rare disease entity that causes substantial morbidity and mortality from septicemia and septic emboli4. Most commonly, septic thrombosis of the vena cava occurs as a complication of prolonged central venous catheterization4,5. Other, uncommon causes include inflammatory processes that extend to the wall of the vena cava6-9. We present here a case of pyogenic spondylitis and disseminated septicemia with septic thrombosis of the vena cava, the common iliac vein, and the renal vein. The patient was informed that the data concerning this case would be submitted for publication. A fifty-six-year-old woman was transferred to our emergency department with a sudden onset of sepsis, with dyspnea, a stuporous mentality, and weakness of both lower extremities. She had been generally in a good state of health until two weeks previously, when she developed lower back pain. She underwent nonoperative treatment for lower back pain during those previous two weeks, and she was given antibiotic treatment (ceftriaxone) for a fever that suddenly developed two days before arrival in our emergency room. She had had diabetes mellitus and high blood pressure for many years. She had no history of intravenous drug or alcohol abuse. There was no …

Pyogenic spinal infections and outcome according to the 36-Item Short Form Health Survey

Pyogenic vertebral infections are rare. In most papers investigators have focused on risk factors, clinical characteristics, and diagnostic findings, and discussed different management strategies. The optimal strategy for dealing with spinal infections, however, remains controversial. Additionally, outcome data regarding quality of life (QOL) after pyogenic spinal infections are sparse. The aim of this study was to provide further data in this field. The authors retrospectively investigated 62 patients suffering from pyogenic spinal infections. In 37 patients (59%), lumbar lesions were observed; thoracic and thoracolumbar infections were documented in 19 (31%) and a cervical infection was demonstrated in six patients (10%). Overall 28 patients (45%) underwent conservative treatment, and 34 (55%) underwent surgery with or without the placement of instrumentation. At follow-up examination the authors recorded each patient's satisfaction as well as QOL according to the 36-Item Short Form Health Survey. Quality of life after treatment of pyogenic spine infections did not reach the level of the normative sample. Most patients continued to suffer some sort of pain. Despite different indications, the surgically treated patients experienced a slightly better QOL and self-reported satisfaction levels, as well as a statistically significant better outcome, than patients treated conservatively. The results obtained in the present study suggest that surgery, especially in conjunction with the placement of instrumentation, may be more beneficial than conservative treatment in patients with a spinal infection.

Concomitant Spine Infection With Mycobacterium Tuberculosis and Pyogenic Bacteria

A case report of an extremely rare condition describing lumbar spine tuberculosis associated with concurrent pyogenic infection is presented. To establish that isolation of pyogenic bacteria from an infected spine does not exclude the possibility of spine tuberculosis. During a MEDLINE data search from January 1960 through October 2001, no cases of combined spine tuberculosis and pyogenic infection were found. A 52-year-old man reported left-side gluteal swelling, backache, and fever of 20 days duration. A similar swelling in the same location had occurred 12 years previously, and an operation was performed at that time. Preoperative syringe-aspirated material from a gluteal abscess was sent for ordinary bacteriologic culture (for only aerobic pyogenic bacteria). During the operation, a needle-aspirated specimen of evacuated pus was subjected to direct microscopy and culture. Direct Gram stain for pyogenic bacteria and direct Ziehl-Neelsen stain for mycobacteria were performed. Cultures for aerobes, anaerobes, mycobacteria, and fungi were made. The preoperative specimen culture showed growth of Nocardia asteroids and Moraxella catarrhalis, whereas the operative specimen showed Gram-positive cocci and acid-fast bacilli on direct smears. The operative cultures yielded growth of Nocardia asteroids, Moraxella catarrhalis, and Mycobacterium tuberculosis. Plain lumbar spine radiograph showed psoas muscle calcification. It is concluded from this case that recovery of pyogenic bacteria from an infected spine does not exclude spine tuberculosis. It is recommended, therefore, that mycobacterial investigations be performed for cases that have evidence of tuberculosis, even when pyogenic microorganisms already have been isolated. The clues that raise suspicion of tuberculosis in patients with pyogenic spine infection include chronic infection that does not respond to ordinary antibiotics, isolated pyogenic bacteria of low virulence, psoas muscle calcification, and immunosuppression.

Pyogenic spine infections: variables affecting the treatment and prognosis

Nitin Tandon, MD, Kelly Frasier, MD, Dennis G. Vollmer, MD, San Antonio, TX, USAIntroduction: The incidence of primary pyogenic infections of the spine has been steadily increasing over the past decade. However, the characterization and management of these infections remains challenging and is often a subject of debate. In this analysis we seek to determine if characterizing these infections based on their anatomic locus assists or obscures the selection of optimal management strategy; evaluate the relationship of the vertebral level of infection to the likelihood of neurological deficits at presentation; ascertain the safety of the implantation of spinal instrumentation and/or devitalized bone (allograft or autograft) in the presence of infection; evaluate the impact of surgical decompression on neurological outcome and create an algorithm, which would provide an objective means of identifying patients who should be managed with surgical debridement up front rather than a trial of medical management.Methods: One hundred and one sequential admissions for noniatrogenic bacterial infections of the spine in 82 patients, managed between May 1996 and December 2000, were reviewed. Data collected include level of spinal involvement, the locus of the infection (intervertebral disc, vertebral body or epidural space), number of segments involved and their imaging characteristics on magnetic resonance imaging (MRI) and computed tomography, the presence of neurological deficits, kyphotic deformity, relapse of infection (in 18 admissions) and outcomes after surgical management. Infections that occurred in a postoperative setting and infections caused by either mycobacteria or fungi were eliminated from this review. Patient data were analyzed for correlations between spinal level of involvement and the presence of neurological deficit, relapses after instrumentation or decompressive surgery and their neurological condition at 6 months after surgery compared with before surgery (graded using the Frankel score). All patients who presented with new deficits underwent surgical decompression unless this was contraindicated by their medical comorbidities or if they refused operative intervention. Surgery for patients without deficits was reserved to those who failed adequate medical therapy and those with significant or progressive kyphosis on plain films.Results: Thirty admissions were managed surgically, 17 of which involved placement of instrumentation and allograft/autograft after debridement of the nidus of the infection. Eleven cases were managed with decompression alone, and one patient underwent grafting and fusion without instrumentation. No patient who underwent placement of bone grafts and/or hardware experienced a relapse of infection nor needed any longer duration of antibiotic therapy. Of the 27 admissions where patients presented with neurological deficits, the average level of the infection was at T3, whereas a similar average for all admissions was at T10. Patients who underwent decompression experienced an average of 1.5 grade improvement in their Frankel score (p<.001), whereas patients with deficits who were managed medically had no significant improvement. The correlation between the locus of infection (eg, epidural space) and the presence of deficits was poor. Surgery directed at draining epidural collections was unrewarding unless there was a clear loculation of purulent material. This could be detected on the preoperative MRI scan as a nonenhancing component in the epidural space with fluid-like intensity signals on the T2-weighted sequences. Relapse rates correlated with shorter duration of antibiotic therapy and multisegmental osseous involvement.Discussion: Instrumentation and bone grafting in the presence of infection may be safely used if indicated for spinal stabilization. Patients presenting with deficits may experience substantial improvement with surgical decompression. Imaging and intraoperative findings suggest that infections of the spine rapidly traverse anatomic boundaries. The broader term “pyogenic spine infection” with or without neurological deficits is preferable to diagnoses that focus on the locus of the infection. This terminology along with an analysis of number and extent of bony segments involved facilitates the decision to manage a patient medically or surgically. An algorithm that takes these multiple factors into account is under development and will assist in a more objective analysis of these patients.

CT of pyogenic spine infection.

A retrospective review of 19 patients with a diagnosis of pyogenic spine infection evaluated with spine CT was performed. In addition to displaying bone involvement, CT routinely depicted paraspinous and epidural involvement often not apparent on conventional radiographs or nuclear medicine studies. CT proved particularly useful in workup of patients with clinical evidence of infection associated with back pain and neurologic symptoms, evaluation of patients with fever and recurrent back pain following recent spine surgery, guiding diagnostic aspiration of suspected spinal regions for culture and sensitivity, pre-operative planning of debridement surgery.