Added value of [18F]fluorodeoxyglucose positron emission tomography/computed tomography for the diagnosis of post-operative instrumented spine infection.

PURPOSE: Post-operative instrumented spine infection (PISI) is an infrequent complication. Diagnosis of spinal implant infection can be difficult, especially in case of chronic infection. METHODS: This retrospective study attempts to evaluate the diagnostic performance of [18F]fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in PISI. Imagings were performed between April 2010 and June 2018 among patients referred for suspected chronic spinal implant infection. PET/CT were performed more than 12 weeks after surgery. PET/CT images were re-interpreted independently by two nuclear medicine physicians without knowledge of the patient's conditions. PET/CT data were analyzed both visually and semi-quantitatively (SUVmax). MRI results were collected from medical records. The final diagnosis of infection was based on bacteriological cultures or a twelve-month follow-up. RESULTS: Forty-nine PET/CT were performed in 44 patients (22 women, median age 65.0 years). Twenty-two patients had a diagnosis of infection during follow-up. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for PET/CT were 86.4%, 81.5%, 79.2%, and 88.0%. Sensitivity, specificity, PPV and NPV were 66.7%, 75.0%, 66.0%, 75.0% respectively for MRI and 50.0%, 92.6%, 84.6% and 69.4% for serum C-reactive protein (CRP). Although these values were higher for PET/CT than for MRI or CRP, the differences were not statistically significant. In this setting, false positives with PET/CT can be observed in case of previous spine infection or adjacent segments disc disease. False negatives can result of extensive instrumented arthrodesis or infection with low virulence bacteria. CONCLUSION: PET/CT is useful for the diagnosis of PISI. These results should be evaluated in further prospective study.

Antibiotic-loaded Porous Alumina Ceramic for One-stage Surgery for Chronic Osteomyelitis.

The classic treatment of chronic osteomyelitis is usually a two-stage surgery combined with systemic antibiotic therapy for several months. We report the case of a patient presenting a chronic osteomyelitis caused by methicillin-resistant Staphylococcus aureus who was treated with a one-stage surgery using an antibiotic-loaded ceramic. We used a porous alumina ceramic loaded with gentamicin to reconstruct the bone removed during débridement and to avoid its colonization. All bacteriological samples performed before and during the surgery revealed the presence of a methicillin-resistant S aureus. Because of the local release of the antibiotic, very high concentrations (more than 50 times the concentration needed) were administered in the surgical wound, thus helping to cure the infection. Owing to the strength of the ceramic, the patient was allowed to walk 10 days after the surgery. After a follow-up at 14 months, the patient is well-being, without any relapse of the infection. The CT-scan follow-up shows an osseointegration of the ceramic. Even, if it is too early to tell that infection is completely cured, these first results are encouraging for the use, in the future, of this antibiotic-loaded ceramic for complex bone infection.

Intrathecal synthesis of specific antibodies as a marker of herpes simplex encephalitis in patients with negative PCR.

BACKGROUND: PCR in the cerebrospinal fluid (CSF) has become the sole method used for the diagnosis of herpes simplex encephalitis (HSE). Nevertheless, PCR results may sometimes be false negative, and in this situation other techniques may be useful. METHODS: 3 patients hospitalised for meningoencephalitis with fever showed a negative result for herpes simplex virus (HSV) PCR in their CSF. We then performed a detection of intrathecal anti-HSV immunoglobulins (IgGs) in the CSF and analysed their level in relation to those in the serum, compared to albumin. RESULTS: We confirmed that IgG synthesis was the direct consequence of an immune system reaction in the 3 patients' CSF. These results were consistent with clinical signs and neurodiagnostic procedures. They prompted us to continue the treatment, which would have been stopped following the negative PCR results. The clinical progression was favourable for all patients. CONCLUSIONS: PCR, which many physicians now consider the gold standard for the detection of HSV, may sometimes yield false negative results, i.e. when performed too early after the disease onset or when the viral load is too low. The method described here, although positive a few days after PCR, may prove helpful in the diagnosis of HSE for patients with negative HSV PCR in the CSF.

Blue light is phototoxic for B16F10 murine melanoma and bovine endothelial cell lines by direct cytocidal effect.

UNLABELLED: The large number of studies devoted to the effect of ultraviolet light on biological systems, contrasts with the lack of experimental data concerning the direct effects of visible light. It has been shown that blue light inhibited the growth of B16F10 melanoma cell lines and reduced the percentage of S phase cells. Yet these effects are poorly understood. MATERIALS AND METHODS: Two cell lines and irradiation with blue light were used. Cell mortality and a possible mechanism of action were investigated. RESULTS: Exposure of B16F10 melanoma and bovine endothelial cells to blue light (wavelength 450 nm, 10 J/cm(2) from a Waldman lamp) induced a rapid and large reduction in viability followed by the death of virtually all the irradiated cells within 24 h. These results led us to expose a patient with haemorrhagic cutaneous melanoma metastasis to blue light. Irradiation led to an immediate arrest of haemorrhage, an inhibition of tumour growth and extensive tumour necrosis 24h after irradiation. CONCLUSION: Exposure to blue light may offer new approaches to the treatment of superficial skin carcinomas in humans.