Imaging does not predict the clinical outcome of bacterial vertebral osteomyelitis

Pyogenic vertebral osteomyelitis: identification of microorganism and laboratory markers used to predict clinical outcome

The aim of this study is to determine the predictive values of laboratory indicators of pyogenic vertebral osteomyelitis (PVO) and a potential cure if the microorganism cannot be identified. Forty-five consecutive patients with PVO were enrolled. Antibiotic therapy with or without surgery was performed according to microorganism. In the negative-culture (NC) group, cefazolin was administered in cases of hematogenous PVO, and vancomycin was administered in cases of postoperative or procedure-related PVO. The clinical, laboratory, and radiological findings were followed up with regard to an appropriate response to antimicrobial therapy. Nine patients were treated with antibiotics alone. We were able to identify the microorganism in 34 cases (75.6%). Ten cases in NC group were cured without recurrence, but one was not. Identification of the microorganisms did not have any significant influence on the treatment outcome, duration of antibiotic administration or normalization of laboratory profiles. For erythrocyte sedimentation rate (ESR) values over 55 mm/h and C-reactive protein (CRP) values of 2.75 mg/dL at fourth week after antibiotic administration by means of ROC curve analysis, we expect significantly high rates of treatment failure by Pearson chi(2) test (chi(2) = 4.344, Odds ratio = 5.15, p = 0.037, 95% CI 1.004-26.597). Even in patients with negative culture findings, it is expected that a good outcome will be achieved by the administration of cefazolin or vancomycin for about 6 weeks. It is concluded that antibiotics selected according to the etiological setting can be initiated without the need to start empirical antibiotics. In every instance at fourth week after the initiation of antibiotic therapy, the values of CRP and ESR can provide meaningful information regarding whether clinicians need to reevaluate the effectiveness of antibiotics by performing follow-up imaging studies and monitoring the patient's clinical manifestations.

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

BACKGROUND

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Prediction of residual disease of spine infection using F-18 FDG PET/CT

STUDY DESIGN

Prospective study.

OBJECTIVE

To determine whether F-18 fluoro-deoxy-glucose positron emission tomography/computed tomography (F-18 FDG PET/CT) follow-up imaging after treatment in patients with spinal infection (SI) could provide useful prognostic information and determine the residual SI.

SUMMARY OF BACKGROUND DATA

There are seldom data on the capability of follow-up imaging methods to predict residual disease and treatment efficacy in patients with SI.

METHODS

Thirty patients with SI underwent F-18 FDG PET/CT at initial and during follow-up. From F-18 FDG PET/CT, quantitative indexes were obtained. The residual SI was determined by the presence of preoperative symptoms, hematological infection marker, and radiologic findings.

RESULTS

The SUVmax were significantly declined after treatment in both of residual (2.85 +/- 1.17 vs. 2.06 +/- 1.03; P < 0.0001) and nonresidual SI (4.31 +/- 2.07 vs. 1.44 +/- 0.46; P < 0.0001). The SUVmean were also decreased after treatment in both of residual (1.45 +/- 0.45 vs. 1.04 +/- 0.29; P = 0.0014) and nonresidual SI (2.09 +/- 1.03 vs. 0.81 +/- 0.25; P < 0.0001). By lesion-based analysis, when < or =43.01% of %deltaSUVmax was used as threshold value, the area under curve (AUC) was 0.879 (P = 0.0001). The sensitivity and specificity were 85.7% and 82.6%, respectively. When < or =44.12% of %deltaSUVmean was used as threshold value, AUC was 0.828 (P = 0.0001). The sensitivity and specificity were 85.7% and 68%, respectively. In patient-based analysis, when < or =46.14% of %deltaSUVmax was used as threshold value, AUC was 0.904 (P = 0.0001). The sensitivity and specificity were 100% and 76.9%, respectively. When < or =41.78% of %deltaSUVmean was used as threshold value, AUC was 0.923 (P = 0.0001). The sensitivity and specificity were 100%, 76.9%, respectively.

CONCLUSION

F-18 FDG PET/CT is useful for discrimination of residual and nonresidual SI after treatment. Among the various quantitative indexes, %deltaSUVmax is a potent predictor of residual SI in the current study.

Hematogenous spinal infection in central Greece

STUDY DESIGN

We retrospectively analyzed spinal infection (SpI), in a teaching Hospital, in Central Greece.

OBJECTIVE

To study presentation, etiology, and outcome of SpI in Central Greece.

SUMMARY OF BACKGROUND DATA

SpI most frequently involves the intervertebral disc and adjacent vertebral bodies and can cause neurologic impairment.

METHODS

Thirty three patients (23 men; age [mean +/- standard deviation], 60.6 +/- 11.3 years; disease duration, 44.5 [+/-54.7] days) hospitalized with SpI between January 2000 and December 2007 were included in the study. All patients had magnetic resonance imaging of the spine.

RESULTS

Nineteen patients had pyogenic SpI (57.6%) and 14 patients had granulomatous SpI, 11 due to Brucella spp (34.4%), 3 due to Mycobacterium tuberculosis (9.4%). Staphylococcus aureus was the most frequent cause of pyogenic SpI, and spondylodiscitis (SpD) was the most frequent localization. Epidural entension was found in 8 of 17 pyogenic SpD and in 2 of 11 brucellar SpD patients. Subdural extension was detected in 3 patients with pyogenic SpD. Blood cultures were positive in 17 of 19 patients with pyogenic SpI. Two patients had concomitant endocarditis (staphylococcal 1, enterococcal 1). The most common associated disease was diabetes mellitus. All but 2 patients received medical treatment alone. Two patients died of uncontrollable sepsis.

CONCLUSION

Back pain in presence of fever, constitutional symptoms, and/or high inflammation markers should alert physicians for spinal infection. In endemic areas, Brucella is a frequent cause of SpI.

[Operative therapy of bacterial spondylodiscitis: a retrospective study]

OBJECTIVE

Bacterial spondylodiscitis is a rare entity in spinal surgery. This study analyses the postoperative results of 53 patients, focusing on the history, the treatment, and the course of the disease.

MATERIAL AND METHODS

This retrospective study is based on the patients' medical charts, including the laboratory and microbiological data.

RESULTS

Twenty-nine patients suffered from different neurological deficits ranging from isolated mild hypaesthesia (n=1) to complete paraplegia (n=6). Depending on the affected area and the extension of the infection, surgery was done either as simple decompression in 16 cases or as decompression combined with a ventral or dorsoventral stabilization in 37 patients. Staphylococcus aureus was the most important triggering organism (n=23). After a median follow-up of 11.25 months, three patients had died, and 22 patients were still disabled because of persisting pain or neurological disturbances.

CONCLUSION

Because of persistent neurological deficits and possible lethal complications, spondylodiscitis remains a severe problem. Management comprises targeted antibiotic therapy and surgery in selected cases.

Pyogenic vertebral osteomyelitis: a systematic review of clinical characteristics

OBJECTIVES

Vertebral osteomyelitis is a cause of back pain that can lead to neurologic deficits if not diagnosed in time and effectively treated. The objective of this study was to systematically review the clinical characteristics of pyogenic vertebral osteomyelitis (PVO).

METHODS

The authors conducted a systematic review of the English literature. The inclusion criteria included studies with 10 or more subjects diagnosed with PVO based on the combination of clinical presentation with either a definitive bacteriologic diagnosis or pathological and/or imaging studies.

RESULTS

The 14 studies that met selection criteria included 1008 patients with PVO. Of them, the majority (62%) were men, with back pain and fever as the most common presenting symptoms. Diabetes mellitus was the most common underlying medical illness, while the urinary tract was the commonest source of infection. Staphylococcus aureus was the most commonly isolated organism. Computed tomographic guided or open biopsy yielded the causative organism more often than blood cultures (77% versus 58%). Plain radiography showed abnormalities in 89% of the cases, while bone scanning and computed tomography or magnetic resonance imaging were positive in 94% of the cases, revealing lumbar as the most commonly affected area. The attributable mortality was 6%, while relapses and neurological deficits were described in the 32% and 32% of the cases, respectively.

CONCLUSION

PVO is an illness of middle-aged individuals with underlying medical illnesses. Although the mortality rate is low, relapses and neurological deficits are common, making early diagnosis a major challenge for the physician.

Extensive spondylodiscitis with epidural abscess causing fever and lower limbs pain in a child with sickle cell disease

Spondylodiscitis is an unusual diagnosis among children and consequent abscess formation is even rarer. A 6-year-old girl with fever, hip pain, and refusal to walk was evaluated. The neurologic examination was normal. Recurrent joint pain with cold weather, iron for anemia without improvement, and decreased intervertebral spaces raised the use of ceftriaxone, oxacillin, and external immobilization. Hemoglobin sickle cell disease, spondylodiscitis with paravertebral collections, and epidural abscess were documented. She was fully recovered. The treatment was conservative because there was no neurologic deficit. We add to the literature 1 case of spondylodiscitis with epidural abscess that was successfully treated with antibiotics alone.

Long-term clinical and radiological magnetic resonance imaging outcome of abscess-associated spontaneous pyogenic vertebral osteomyelitis under conservative management

OBJECTIVES

Management of abscess-associated spontaneous pyogenic vertebral osteomyelitis (PVO) is controversial. The role of magnetic resonance imaging (MRI) in follow-up and its relation with clinical outcome is often unclear. This study evaluates the clinical and MRI outcome of abscess-associated PVO under conservative treatment.

METHODS

Prospective study and retrospective review of patients with spontaneous PVO in whom the initial MRI showed soft-tissue involvement (STI). Treatment according to a medical protocol, clinical and MRI follow-up at diagnosis, and at 2 later time points: early response (ER, at the end of antibiotic therapy) and late response (LR, >or=6 months after therapy). MRI classified STI as soft-tissue edema (STE) or abscess.

RESULTS

Of the 27 patients (20 men, 74%, age 65+/-14), all had pain, 17 (63%) had fever, and 6 (22%) had mild neurological impairment. The main etiology was Staphylococcus sp (11, 41%). Twenty-one (81%) had bacteremia and 18 (67%) had epidural/paraspinal abscess. Patients received antibiotics for 9 weeks, administered orally for 6 weeks. ER: Three cases failed and general improvement was seen in the remainder. MRI showed persistent STI, which diminished in all cases except 1, whereas bone/disc findings remained. LR: All patients were cured; 8 reported mild sequelae (30%). MRI still revealed bone/disc abnormalities, but residual STE was infrequent. Median follow-up was 29 months.

CONCLUSION

Most patients with abscess-associated spontaneous PVO are cured with a conservative approach. MRI shows STI reduction at ER evaluation. Repeat MRI is probably unnecessary if clinical and laboratory outcomes are satisfactory. The persistence of bone/disc MRI findings alone does not represent therapeutic failure.