Pyogenic spondylodiskitis: a radiologic/pathologic and culture correlation study

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.

Predictive factors for positive disco-vertebral biopsy culture in pyogenic vertebral osteomyelitis, and impact of fluoroscopic versus scanographic guidance

Background

The aims of this study were to identify the predictive factors for microbiological diagnosis through disco-vertebral biopsy (DVB) in patients with pyogenic vertebral osteomyelitis (PVO) and negative blood cultures, and compare the performance of DVB under fluoroscopic versus scanographic guidance.

Methods

We performed a cohort study comparing positive and negative DVB among patients with PVO. All cases of PVO undergoing a DVB for microbiological diagnosis in our center were retrospectively reviewed. Infections due to Mycobacterium tuberculosis, infections on foreign device, and non-septic diseases were excluded. Anamnestic, clinical, biological, microbiological, as well as radiological data were collected from medical charts thanks to a standardized data set.

Results

A total of 111 patients were screened; 88 patients were included. Microbiological cultures were positive in 53/88 (60.2%) patients. A thickening of the paravertebral tissue ≥10 mm on magnetic resonance imaging (MRI) in axial MR scans was a predictive factor of DVB microbiological positivity (52.4% vs. 13.3%; p = 0.006; OR = 5.4). Overall, 51 DVB were performed under fluoroscopic guidance and 37 under scanographic guidance. Considering lumbar DVB, 25/36 (69.4%) of cases yielded positive results under fluoroscopic guidance versus 5/15 (33.3%) under scanographic guidance (p = 0.02; OR = 4.4). No adverse event linked to DVB was notified.

Conclusion

Every patient with PVO and negative blood cultures should undergo a DVB. A thickening of the paravertebral tissue ≥10 mm on MRI is associated with a higher rate of positive DVB culture. A lumbar DVB under fluoroscopic guidance is more sensitive than under scanographic guidance to identify the micro-organism involved.

Spondylodiscitis: experience of surgical management of complicated cases after failed antibiotic treatment

INTRODUCTION

The term Spondylodiscitis (SD) involves infection of the vertebra (Spondylitis), infection of the intervertebral disc (Discitis), or both (Spondylodiscitis). SD represents a diagnostic and therapeutic challenge to any spine surgeon. Any delay in its diagnosis or management may cause serious long-term morbidity or even lead to mortality. In this study, we report the experience of our Institution in the management of severe and complicated cases of SD.

METHODS

Over a period of 1 year, 39 patients with the diagnosis of SD were surgically treated in Assiut University Hospital, Assiut, Egypt. The management processes were tailored according to the clinical condition, radiological and lab studies of each case; and patients were then prospectively followed-up until they were cured (for a minimum of 6 months). The outcomes were analyzed, to be able to give recommendations while aiming to improve the overall outcome of such dangerous health issue.

RESULTS

In this series, patients were managed surgically by drainage and debridement of the infection site with/without instrumented fusion. Results included: satisfactory fusion was achieved in 97.3% of patients (confidence interval [CI] = 0.6856-1.3421). Neurological Improvement Rate (NIR) was 71.5% (Statistically significant improvement P-value = 0.014) and reoperation rate was 5% (CI = 0.00621-0.18525). Mortality rate was 7.7% (CI = 0.016-0.209). Several aspects were analyzed in each case.

CONCLUSION

Surgical management of severe and complicated cases of SD allows for effective debridement and rapid cure of inflammation, earlier patient mobilization and significantly shorter duration of antibiotic usage.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Spontaneous corynebacterium spondylodiskitis in an immunocompetent patient: A case report and literature review

BACKGROUND

Spontaneous Corynebacterium spondylodiskitis is an unusual diagnosis of spondylodiskitis, especially in healthy patients without any significant past medical history.

MATERIALS AND METHODS

We describe the case of a 78-year-old man with progressive low back pain for 3 months, irradiating down the lower limbs through L5 and S1 root pathways, associated with distal muscle weakness in both lower limbs. He had no history of trauma or medical problems. Laboratory investigation revealed elevated serum C-reactive protein (CRP) and erythrocyte sedimentation rate, without leukocytosis. The magnetic resonance findings demonstrated an extensive L5-S1 spondylodiskitis and L4-L5 anterolisthesis. Prior to spinopelvic fixation and posterolateral fusion, a substantial debridement was performed. The obtained tissue samples were submitted to pathological and microbiological studies, which identified Corynebacterium infection.

RESULTS

One month after surgery, the pain diminished dramatically and the CRP titer diminished significantly.

CONCLUSION

Although cases are very rare, spontaneous Corynebacterium spondylodiskitis, with substantial invasion of the spine, may develop in patients lacking any history of medical or surgical problems.

Bacterial Diskospondylitis Associated with Posterior Paresis/Paralysis in North American Farmed Mink (Mustela vison)

Posterior paresis/paralysis in farmed mink is responsible for significant morbidity and mortality, with individual farms reporting the loss of as many as 700 animals each year. Although this disease has been recognized by North American mink farmers for approximately 40 years, there are few published reports focusing on this entity. The objective of this study was to investigate the etiology and pathogenesis of the disease. Complete necropsy examinations were done on 40 clinically affected mink, ranging from 7 to 10 weeks of age, and on three normal animals in the same age range from two mink farms. Thirty-two of the 40 clinically affected animals had an isolated vertebral lesion characterized by bone lysis and proliferation that usually was centered on an intervertebral disk space in the midthoracic area. An inflammatory reaction, composed primarily of neutrophils, was present within the vertebral sections in 25 of the 40 affected animals (62.5%), and the presence of gram-positive cocci was confirmed in 8 of 10 animals (80%) in which bacterial organisms were observed histologically. Bacterial cultures from 15 affected animals yielded Streptococcus sp. from the intervertebral disk space in 13 of 15 (86.7%) animals and from heart blood in 6 of 8 (75%). A farm visit revealed no history or evidence of traumatic wounds as a source of infection in these animals, and the diet appeared to be adequate for skeletal development. We conclude that posterior paresis/paralysis in farmed mink is associated with bacterial diskospondylitis, likely occurring secondary to bacteremia/septicemia.

Pedicle screw-rod fixation: a feasible treatment for dogs with severe degenerative lumbosacral stenosis

Background

Degenerative lumbosacral stenosis is a common problem in large breed dogs. For severe degenerative lumbosacral stenosis, conservative treatment is often not effective and surgical intervention remains as the last treatment option. The objective of this retrospective study was to assess the middle to long term outcome of treatment of severe degenerative lumbosacral stenosis with pedicle screw-rod fixation with or without evidence of radiological discospondylitis.

Results

Twelve client-owned dogs with severe degenerative lumbosacral stenosis underwent pedicle screw-rod fixation of the lumbosacral junction. During long term follow-up, dogs were monitored by clinical evaluation, diagnostic imaging, force plate analysis, and by using questionnaires to owners.

Clinical evaluation, force plate data, and responses to questionnaires completed by the owners showed resolution (n = 8) or improvement (n = 4) of clinical signs after pedicle screw-rod fixation in 12 dogs. There were no implant failures, however, no interbody vertebral bone fusion of the lumbosacral junction was observed in the follow-up period. Four dogs developed mild recurrent low back pain that could easily be controlled by pain medication and an altered exercise regime.

Conclusions

Pedicle screw-rod fixation offers a surgical treatment option for large breed dogs with severe degenerative lumbosacral stenosis with or without evidence of radiological discospondylitis in which no other treatment is available. Pedicle screw-rod fixation alone does not result in interbody vertebral bone fusion between L7 and S1.

Surgical site infections following spine surgery: eliminating the controversies in the diagnosis

Surgical site infection (SSI) following spine surgery is a dreaded complication with significant morbidity and economic burden. SSIs following spine surgery can be superficial, characterized by obvious wound drainage or deep-seated with a healed wound. Staphylococcus aureus remains the principal causal agent. There are certain pre-operative risk factors that increase the risk of SSI, mainly diabetes, smoking, steroids, and peri-operative transfusions. Additionally, intra-operative risk factors include surgical invasiveness, type of fusion, implant use, and traditional instead of minimally invasive approach. A high level of suspicion is crucial to attaining an early definitive diagnosis and initiating appropriate management. The most common presenting symptom is back pain, usually manifesting 2–4 weeks and up to 3 months after a spinal procedure. Scheduling a follow-up visit between weeks 2 and 4 after surgery is therefore necessary for early detection. Inflammatory markers are important diagnostic tools, and comparing pre-operative with post-operative levels should be done when suspecting SSIs following spine surgery. Particularly, serum amyloid A is a novel inflammatory marker that can expedite the diagnosis of SSIs. Magnetic resonance imaging remains the diagnostic modality of choice when suspecting a SSI following spine surgery. While 18F-fluorodeoxyglucose-positron emission tomography is not widely used, it may be useful in challenging cases. Despite their low yield, blood cultures should be collected before initiating antibiotic therapy. Samples from wound drainage should be sent for Gram stain and cultures. When there is a high clinical suspicion of SSI and in the absence of superficial wound drainage, computed tomography-guided aspiration of paraspinal collections is warranted. Unless the patient is hemodynamically compromised, antibiotics should be deferred until proper specimens for culture are secured.

Therapeutic impact of organism isolation in management of patients with pyogenic vertebral osteomyelitis

In management of patients with pyogenic vertebral osteomyelitis, organism isolation by biopsy is generally considered to be of primary importance when constructing a treatment plan. In our clinical practice, however, patients can be successfully treated even without identifying the organisms. The objective of this study is to review our clinical experiences and clarify the therapeutic impact of organism isolation. Forty patients who were conservatively managed in our institution constituted the base of this study. The average follow-up period was 16.7 months. Among the study subjects, 13 patients underwent percutaneous needle biopsy and the organism was identified in 6 patients. Additionally, the organism was isolated from the sample obtained from blood and possible foci in 10 patients. In total, the causative organism was identified in 15 of the 40 patients (37.5%). Patients were divided into two groups based on whether the organism was identified by culture (Groups A and B, with and without organism isolation respectively). The duration of antibiotic therapy was not significantly different between the groups (Group A: 4.8 ± 1.6 months, Group B: 4.3 ± 2.1 months), while subsequent mortalities in Group A and B were 13.3% and 8% without significant intergroup difference. Organism isolation did not productively help select the effective antibiotics and reduce the treatment period or mortality rate in treatment of patients with pyogenic vertebral osteomyelitis. Therefore, current strategic antibiotic therapy may be effective in eradicating infection even without identification of the causative organism in treatment of patients with pyogenic vertebral osteomyelitis.

Invasive Staphylococcus aureus infections in diabetes mellitus

Staphylococcus aureus, the most virulent of the many staphylococcal species, has remained a major cause of morbidity and mortality despite the availability of numerous effective anti-staphylococcal antibiotics. S. aureus causes disease through both toxin-mediated and non-toxin-mediated mechanisms. This organism is responsible for both healthcare associated and community-based infections ranging from relatively minor skin and soft tissue infections to severe life threatening systemic infections. Patients with diabetes mellitus are at increased risk of invasive S. aureus infections. This article focuses on the spectrum of invasive S. aureus infections and discusses the clinical features, investigations and management of these infections in patients with diabetes mellitus.

Spondylodiscitis occurring after diagnostic lumbar puncture: a case report

Spondylodiscitis is a rare disease which is generally seen after long-term epidural catheterization. However, spondylidiscitis developing after diagnostic lumbar puncture is very rare. Early diagnosis has a crucial role in the management of the disease and inclines the morbidity rates. However, the diagnosis is often delayed due to the rarity and insidious onset of the disease usually presenting with low back pain which has a high frequency in the society. If it is diagnosed early before development of an abscess requiring surgery or neurological deficit, it responds to antimicrobial therapy quite well. We report 66-year-old male case of spondylodiscitis developing after diagnostic lumbar puncture. The patient was treated with antimicrobial therapy. After antimicrobial therapy, findings of spondylodiscitis were completely resolved and no recurrence was seen in the period of 9-month followup.

Vertebral osteomyelitis and epidural abscess due to Aspergillus nidulans resulting in spinal cord compression: case report and literature review

Vertebral osteomyelitis caused by Aspergillus nidulans is rare and usually affects immunocompromised patients. This report presents a case of thoracic vertebral osteomyelitis with epidural abscesses due to A. nidulans in a 40-year-old immunocompetent female who presented with back pain, numbness and weakness of both lower limbs. Magnetic resonance imaging demonstrated osteomyelitis involving the thoracic (T)1-T3 vertebral bodies with epidural abscesses, resulting in spinal compression. The patient underwent a decompression laminectomy of T1-T3 and debridement of the thoracic epidural inflammatory granuloma. Histopathology revealed fungal granulomatous inflammation. The patient received 6 mg/kg voriconazole every 12 h (loading dose on day 1) followed by 4 mg/kg voriconazole twice daily for 1 month, administered intravenously. The patient returned with recurrent back pain 16 months after initial presentation. A. nidulans was identified by fungal culture and polymerase chain reaction. The patient showed no evidence of recurrence 1 year after a 6-month course of oral voriconazole. The key to the effective treatment of Aspergillus osteomyelitis is not to excise the abscess, but to administer systemic antifungal drug therapy.

Imaging of spine infection

This article reviews the imaging and relevant clinical details of infection of the extradural spine. Spine infections are increasing in incidence and in frequency of diagnosis. They are clinically important despite their relative rarity, because they may be life-threatening, and because early diagnosis leads to improved outcomes. The focus is on pyogenic spondylodiscitis. The also typically pyogenic conditions of epidural and subdural abscess, facet joint infection, and pyomyositis are discussed. Nonpyogenic, granulomatous infections are also addressed. Magnetic resonance imaging is emphasized. The radiologist's role in performing minimally invasive sampling procedures is highlighted.

Vertebral osteomyelitis: eight years' experience of 100 cases

To evaluate the etiology and characteristics of vertebral osteomyelitis cases in our country, patients with vertebral osteomyelitis between January 2000 and December 2007 were included in this study. Clinical and laboratory data of the patients were collected from the medical records retrospectively. Of these 100 patients, 44 had pyogenic, 24 had brucellar, and 32 had tuberculous spondylodiscitis. The age of the patients ranged from 13 to 82 years, with a mean of (SD±) 55 ± 15.6 years. Within the pyogenic group, 10 (22.7%) patients had a spinal surgery history, and in 18 patients of the pyogenic group, an etiological agent was isolated. Ten (56%) of these 18 were methicillin-sensitive Staphylococcus aureus. While all of the patients included in this study suffered from pain, 49 of these had fever. Sixty-nine percent of the patients had lumbar involvement. The etiological distribution may differ according to geographical areas. Although brucella and tuberculosis (TB) are endemic in our country, pyogenic vertebral osteomyelitis was more frequent. The most common involved area in our patients was the lumbar vertebrae. Although thoracic involvement may be more predominant in tuberculous vertebral osteomyelitis, it does not strongly suggest TB. Magnetic resonance imaging may exclude some disorders mimicking vertebral osteomyelitis and may delineate the degree of the involvement. Microbiological and/or histopathological examination of computerized tomography-guided fine-needle aspiration biopsies are the mainstays for the diagnosis. Suspicion and early diagnosis seem critical for preventing sequelae development.

Spondylodiscitis: update on diagnosis and management

Spondylodiscitis, a term encompassing vertebral osteomyelitis, spondylitis and discitis, is the main manifestation of haematogenous osteomyelitis in patients aged over 50 years. Staphylococcus aureus is the predominant pathogen, accounting for about half of non-tuberculous cases. Diagnosis is difficult and often delayed or missed due to the rarity of the disease and the high frequency of low back pain in the general population. In this review of the published literature, we found no randomized trials on treatment and studies were too heterogeneous to allow comparison. Improvements in surgical and radiological techniques and the discovery of antimicrobial therapy have transformed the outlook for patients with this condition, but morbidity remains significant. Randomized trials are needed to assess optimal treatment duration, route of administration, and the role of combination therapy and newer agents.

New needle biopsy technique for lumbar pyogenic spondylodiscitis

STUDY DESIGN

Case series.

OBJECTIVE

To improve the isolation rate for pyogenic spondylodiscitis, we developed a new needle biopsy technique.

SUMMARY OF BACKGROUND DATA

The biggest problem in treating lumbar pyogenic spondylodiscitis is a low success rate in isolating a causative microorganism. The rates have been reported 42% to 64%.

METHODS

There are 3 steps: (A) Insert a 21-G needle as for discography, aspirate pus or fluid as specimen. (B) If step A fails, inject saline and collect fluid as reflux. (C) If step B fails, insert another needle into the disc, inject saline and collect reflux from the other needle. We applied this approach to 12 patients with a mean age of 64.3 years.

RESULTS

We were able to collect fluid samples in all cases and the culture was positive in 11 cases (91.6%). Staphylococcus aureus was the most frequently identified organism (41.7%).

CONCLUSION

This simple method improved the isolation rate and should improve the treatment of lumbar pyogenic spondylodiscitis.

Spondylodiscitis associated with multiple level involvement and negative microbiological tests: an unusual case

STUDY DESIGN

A case report.

OBJECTIVE

To report an unusual case of spondylodiscitis with multiple level involvement.

SUMMARY OF BACKGROUND DATA

Spondylodiscitis, an infection of the intervertebral disc space, vertebral bodies, or the paraspinal epidural space can be a serious disease because of diagnostic delay and inadequate treatment.

METHODS

A previously healthy, 52-year-old man was presented to our outpatient clinic with a complaint of acute, atraumatic onset of severe back pain for more than 1 month. Initially, he was misdiagnosed at another clinic as myofascial pain and treated with nonsteroidal anti-inflammatories and physical therapy, which he did not benefit from. He never complained of fever; however, laboratory tests revealed raised erythrocyte sedimentation values, increased C-reactive protein values but normal leukocyte count. Thoracal and lumbal plain radiographs were nonspecific. Magnetic resonance imaging demonstrated increased signal intensity in vertebral bodies and intervertebral disc space through T12-L4 and in the paravertebral musculature at L2-L3 with contrast enhancement. Blood cultures and computed tomography-guided needle biopsy and cultures were negative.

RESULTS

The patient was treated with oral amoxicillin and clavulanate and responded very well clinically; however, imaging examinations were repeated up to 6 months because of multilevel involvement. Follow-up magnetic resonance imaging findings at 3 months and 6 months showed decreased signal intensity, and luckily, there was no evidence of vertebral destruction.

CONCLUSION

Diagnosis of spondylodiscitis could be challenging and commonly missed; however, it should always be included in the differential diagnoses of back pain in the middle aged and healthy population.

Unusual manifestations of vertebral osteomyelitis: intraosseous lesions mimicking metastases

BACKGROUND AND PURPOSE

Vertebral osteomyelitis can have different imaging manifestations. The purpose of this study was to demonstrate the unusual MR imaging patterns of vertebral osteomyelitis with intraosseous lesions mimicking metastases.

MATERIALS AND METHODS

From September 2000 to August 2007, 7 patients were selected from our data base of 214 patients with confirmed vertebral osteomyelitis and MR images. All of those having misinterpreted MR imaging reports and unusual imaging patterns were analyzed. The presence of a peripheral curvilinear area of low signal intensity in an osseous lesion (the rim sign) and a peripheral rim of high signal intensity on T2-weighted images around an osseous lesion (the halo sign) was evaluated. Follow-up MR imaging studies were performed in all patients.

RESULTS

The patients were 5 men and 2 women, with an age range of 42-80 years. MR imaging findings of those with vertebral osteomyelitis showed a solitary lesion in 2 and multiple lesions in 5 patients. The intraosseous lesions revealed low signal intensity on T1-weighted images, mixed or high signal intensity on T2-weighted images, high signal intensity on short tau inversion recovery images, and global or marginal enhancement. The rim sign was found in 6 (86%) patients; halo sign, in 7 (100%); preserved intervertebral disks, in 7 (100%); and limited paraspinal or epidural inflammation, in 6 (86%). Images of all patients demonstrated healing or almost healed changes on the follow-up MR imaging studies.

CONCLUSION

Vertebral osteomyelitis can have MR imaging patterns mimicking osseous metastases. Recognition of these unusual imaging manifestations, together with clinical and histopathologic analysis, may aid in reaching the correct diagnosis.

Spinal arthropathy associated with Ochrobactrum anthropi in free-ranging cane toads (Chaunus [Bufo] marinus) in Australia

Inflammatory or degenerative pathology involving the vertebral bodies and/or ventral intervertebral joints has been described in numerous species, both captive and free ranging, including mammals, birds, and snakes, although never in amphibians. We described 15 cases of a newly recognized spinal arthropathy in adult cane toads (Chaunus [Bufo] marinus), an invasive species in Australia. Grossly appreciable lesions consisted primarily of ventral proliferation of bone and cartilage that resulted in ankylosis. Histologic examination of the entire vertebral columns of the 15 affected toads revealed 13 toads to have lesions at multiple intervertebral sites, totalling 41 intervertebral joints with lesions. Most lesions involved bone and cartilage proliferation that resulted in fusion of the joint, with (n = 15) or without (n = 9) associated pyogranulomatous inflammation. In the remaining 17 affected joints, histologic lesions were characterized by degeneration of articular cartilage without joint fusion. In addition, in one of these joints, there was also hemorrhage and pyogranulomatous inflammation. Bacterial culture of affected joints in 9 toads and grossly normal joints in 4 control toads resulted in isolation of Ochrobactrum anthropi in 7 affected toads but in none of the controls (P < .01). We proposed an interaction between degenerative and bacterial etiologies in the pathogenesis of this condition. Invasive toads may be predisposed to this condition because of their large size; increased rates of movement; and, possibly, immunosuppression resulting from inhabiting a novel environment.

Invasion, stress, and spinal arthritis in cane toads

The impact of invasive species on biodiversity has attracted considerable study, but impacts of the invasion process on the invaders themselves remain less clear. Invading species encounter conditions different from those in their ancestral habitats and are subject to intense selection for rapid dispersal. The end result may be significant stress on individual organisms, with consequent health problems. Our studies on invasive cane toads in Australia reveal severe spinal arthritis in approximately 10% of large adult toads, associated with the same factors (large body size, frequent movement, and relatively long legs) that have enabled toads to invade so rapidly across the Australian tropics.

[Surgical management of spondylodiscitis. An analysis of 78 cases]

Spondylodiscitis is a rare bacterial infection of the spine with an inflammatory, destructive course. To obtain further information on the therapeutic management and clinical course of spondylodiscitis, we retrospectively investigated 78 patients after surgical intervention. Mean age was 64 years (+/-4.6 years; range 21-80 years), the mean length of stay 49 days (+/-8.2 days; 3-121 days) including 24 days (+/-4.7 days; 0-112 days) in ICU. In hospital mortality was 9%. The cervical spine was affected in 10%, the thoracic spine in 35% and the lumbar/sacral spine in 55% of patients. Abscess formation occurred in 65% and destruction of the vertebral body in 74%. A total of 75% of patients presented with neurological deficits which could be improved by surgical intervention in 82% of cases. 24 patients were treated by ventral debridement and stabilization alone, 20 patients with a combined dorsoventral method. Most patients (n=34) were stabilized via dorsal bridging instrumentation without ventral debridement of the focus. Of this group, 23 patients were initially scheduled for secondary ventral debridement but complete healing was achieved prior to this, so further surgical therapy was unnecessary. Successful cure was obtained in 92% of cases. Based on our findings, we favor a split surgical approach: initially with dorsal internal fixation only. Abscesses can be drained percutaneously. Ventral debridement and stabilization is only recommended if insufficient stability can be obtained by dorsal fixation alone, as shown by the persistence of infection or pain.

Signalment and clinical features of diskospondylitis in dogs: 513 cases (1980-2001)

OBJECTIVE

To determine signalment, clinical features of the disease, and treatment in dogs with diskospondylitis.

DESIGN

Case-control study.

ANIMALS

513 dogs with diskospondylitis (cases) and 236,109 canine hospital accessions (controls) from 12 veterinary teaching hospitals.

PROCEDURE

Information retrieved from the medical records of 123 dogs with diskospondylitis at the Louisiana State University veterinary teaching hospital between 1980 and 2001 included sex, age, breed, primary complaint, neurologic status, location of lesions, causative organism, treatment, and outcome. The signalment of 390 additional cases from 11 other veterinary teaching hospitals was accessed from the Veterinary Medical Database. Comparisons were made with controls from the same time periods.

RESULTS

Male dogs were twice as likely as female dogs to be affected (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.7 to 2.4). Dogs were significantly more likely to be affected as age increased. Purebred dogs, especially Great Danes, were more likely than mixed-breed dogs to be affected (OR, 73; CI, 4.3 to 12.6). For dogs from Louisiana State University, Staphylococcus spp, Brucella spp, Streptococcus spp, and Escherichia coli were isolated most often; multiple organisms were detected via microbial culture in 11 dogs. The mean duration of treatment was 53.7 weeks.

CONCLUSIONS AND CLINICAL RELEVANCE

Male dogs, older dogs, and Great Danes appeared more likely to be affected with diskospondylitis than female dogs, dogs < 1 year of age, and mixed-breed dogs, respectively. Long-term administration of antimicrobial drugs for treatment of diskospondylitis may be expected. Identification of the causative organism and early treatment are recommended.

Suspected disk space infection with negative microbiological tests—report of eight cases and comparison with documented pyogenic discitis

Few data are available on patients with suspected noniatrogenic pyogenic discitis but negative microbiological tests.

OBJECTIVES

To compare the features, treatment, and outcomes in patients with suspected versus microbiologically documented noniatrogenic pyogenic discitis.

PATIENTS

A retrospective chart review identified eight patients with suspected noniatrogenic pyogenic discitis managed at our institution over a 15-year period. Eighteen age- and sex-matched patients with microbiologically documented noniatrogenic pyogenic discitis managed at our institution during the same period served as controls.

RESULTS

The eight cases had a longer time to diagnosis, a greater risk of abscess formation or epidural infection, and a smaller number of cutaneous portals of entry, as compared to the controls. None of the cases had evidence of endocarditis or diabetes mellitus. Infection at another site preceded the discitis in half the cases. Empirical treatment with two antimicrobials (usually a fluoroquinolone with a beta-lactam or fosfomycin) ensured a full recovery in all eight cases, with no relapses or long-term recurrences, whereas relapses occurred in three of the 18 controls treated with antibiotics selected by antibiotic susceptibility testing.

CONCLUSION

Noniatrogenic pyogenic discitis with negative microbiological studies is associated with distinctive clinical features consistent with smoldering infection. The outcome is favorable under empirical two-drug antimicrobial therapy, usually including a fluoroquinolone given by the intravenous route.

Percutaneous transpedicular discectomy and drainage in pyogenic spondylodiscitis

The natural history of uncomplicated hematogenous pyogenic spondylodiscitis is self-limiting healing. However, a variable degree of bone destruction frequently occurs, predisposing the spine to painful kyphosis. Delayed treatment may result in serious neurologic complications. Early debridement of these infections by percutaneous transpedicular discectomy can accelerate the natural process of healing and prevent progression to bone destruction and epidural abscess. The purpose of this manuscript is to present our technique of percutaneous transpedicular discectomy (PTD), to revisit this minimally invasive surgical technique with stricter patient selection, and to exclude cases of extensive vertebral body destruction with kyphosis and neurocompression by epidural abscess, infected disc herniation, and foraminal stenosis. In a previously published report of 28 unselected patients with primary hematogenous pyogenic spondylodiscitis, the immediate relief of pain after PTD was 75%, and in the long-term follow-up, the success rate was 68%. Applying stricter patient selection criteria in a second series of six patients (five with primary hematogenous spondylodiscitis and one with secondary postlaminectomy-discectomy spondylodiscitis), all patients with primary hematogenous spondylodiskitis (5/5) experienced immediate relief of pain that remained sustained at 12-18 months follow-up. This procedure was not very effective, however, in the patient who suffered from postlaminectomy infection. This lack of response was attributed to postlaminectomy-discitis instability. The immediate success rate after surgery for unselected patients in this combined series of 34 patients was 76%. This technique can be impressively effective and the results sustained when applied in the early stages of uncomplicated spondylodiscitis and contraindicated in the presence of instability, kyphosis from bone destruction, and neurological deficit. The special point of this procedure is a minimally invasive technique with high diagnostic and therapeutic effectiveness.

[Osteomyelitis of the spine]

Spinal infections are rare, occurring most often in elderly patients with urinary tract infections or diabetes. With the increasing number of patients with immune suppression, and also the increasing number of immigrants in the population, spinal infections are seen more frequently, especially in young adults. Typically spinal infections are monomicrobial, Staphylococcus aureus being the most common organism. Hematogenous spread of bacteria through the arterial paravertebral collateral vessels into the subchondral bone marrow of the vertebral bodies is the most common source of infection. Clinical presentation is often nonspecific. Important diagnostic measurements are laboratory studies, radiological evaluation including MR image scans, and CT-guided percutaneous biopsy of the lesion for microbiological studies. The management of spinal infections consists of antimicrobial therapy over 6-8 weeks. Surgical intervention is indicated in neurologically compromised patients for spinal instability and abscesses.

Iatrogenic spondylodiscitis

Iatrogenic intervertebral disc space infection is encountered following microsurgical discectomy, percutaneous laser disc decompression, automated percutaneous lumbar nucleotomy operations, and discography. The purpose of this paper is to present a case report and review the literature on the uncommon origins of pyogenic spondylodiscitis and to emphasize the significance of prophylactic antibiotic therapy following transrectal ultrasonography-guided needle biopsy of the prostate (TUGNBP). According to the authors, this is the first reported case of pyogenic spondylodiscitis as a complication of TUGNBP in the English language literature.

Surgical treatment of spondylodiscitis

BACKGROUND

Spondylodiscitis is a rare bacterial infection of the vertebra and intervertebral discs with an inflammatory, destructive course.

METHODS

To gain further information about the management and clinical course of spondylodiscitis, we retrospectively reviewed 32 patients in 2002 who had surgical interventions between 1992 and 2001.

RESULTS

The mean age of patients was 61 years (29-78 years). The mean hospital stay was 47 days (+/- 5.6 days; 3-121 days), including 28 days (+/- 8.1 days; 2-112 days) in the ICU. In-hospital mortality was 6%. The cervical spine was affected in 20% of patients (6/32), the thoracic spine in 25% (8/32), and the lumbosacral spine in 55% (18/32). Abscesses occurred in 63% of patients (20/32) and destruction of the vertebral body in 71% (23/32). Neurological deficits were present in 17 patients, which improved by surgical intervention in 82% of those affected. Thirty-one patients underwent ventral resection of the focus, spondylodesis with a bone graft or titanium cage, and ventral stabilization with a plate. In 19% of patients (6/32), additional dorsal bridging instrumentation was performed. Complete healing was obtained in 94% (30/32) patients. At follow-up, 50% of patients (16/32) had no complaints.

CONCLUSIONS

Spondylodiscitis requires immediate debridement of the focus, with decompression and stabilization through a ventral approach, when conservative management fails. Otherwise, severe complications occur, such as sepsis, vertebral body destruction, abscess, or neurological deficits.

The etiologic diagnosis of infectious discitis is improved by amplification-based DNA analysis

OBJECTIVE

Blood cultures and cultures of disc material are required to identify and treat bacterial agents responsible for septic spondylodiscitis, but these methods have limited sensitivities. We undertook this study to compare nonculture amplification-based DNA analysis with conventional culture of disc aspirate.

METHODS

Nineteen patients with spondylodiscitis, including 11 with a history of spinal surgery, presented with negative blood cultures and underwent percutaneous disc or epidural abscess puncture for bacterial diagnosis. Amplification by polymerase chain reaction was performed on 16S ribosomal DNA universal target genes and femA staphylococci-specific target genes in all patients, and on the upstream p34 mycobacterial gene in 1 patient. Species identification relied on amplicon sequencing and comparison with templates from GenBank. Amplification of the femA gene led to subsequent testing for methicillin resistance by amplification of the mecA gene. Further assessment using a staphylococci- and methicillin resistance-specific DNA array was performed on 3 samples.

RESULTS

Microbiologic and molecular assays identified the causative organism in 14 of 19 patients (74%) and 19 of 19 patients (100%), respectively. In culture-positive patients, DNA-based and microbiologic results were highly correlated. Five agents (Staphylococcus simulans, Staphylococcus sciuri, Brucella species, Actinomyces israelii, and Mycobacterium tuberculosis complex) were identified only by DNA-based methods. In 1 sample, Corynebacterium jeikeium and coagulase-negative Staphylococcus were both cultured, whereas DNA analysis identified only Staphylococcus hominis.

CONCLUSION

DNA-based methods are highly sensitive and specific. They can usefully complement standard microbiologic methods for identifying the cause of infectious spondylodiscitis and contribute to species-specific therapeutic orientation in patients with negative blood and disc aspirate cultures.