Bone flap infections after craniotomy. A review of 63 cases and the implications for definitions, classification and surveillance methodologies

BACKGROUND

Bone flap infections (BFI) occur following neurosurgical procedures such as craniotomies. However, they are poorly defined and often not clearly differentiated from other surgical site infection neurosurgery.

AIM

To review data from a national adult neurosurgical centre to explore some clinical aspects to better inform definitions, classification and surveillance methodologies.

METHODS

We retrospectively reviewed data on clinical samples sent for culture from patients with suspected BFI. We also accessed information recorded prospectively from national and local databases for evidence of BFI or related conditions based upon terms used in surgical operative notes or discharge summaries and documented monomicrobial and polymicrobial infections related to craniotomy sites.

FINDINGS

Between January 2016 and December 2020, we documented 63 patients with a mean age of 45 years (16-80). Craniectomy for infection of the skull was the most common terminology used to describe BFI in the coding used in a national database, 40/63 (63%), but other terms were used. A malignant neoplasm was the most common underlying condition necessitating craniectomy in 28/63 (44%) cases. Specimens submitted for microbiological investigation included 48/63 (76%) bone flaps, 38/63 (60%) fluid/pus, and 29/63 (46%) tissue. Fifty-eight (92%) patients had at least one culture positive specimen; 32 (55%) were monomicrobial and 26 (45%) were polymicrobial. Gram-positive bacteria predominated and Staphylococcus aureus was the most common.

CONCLUSION

Greater clarity on how to define BFI is required to enable better classification and the carrying out of appropriate surveillance. This will inform preventative strategies and more effective patient management.

Multidisciplinary neurosurgical rounds incorporating antimicrobial stewardship. Are they of benefit?

Background

In an era of increasing antimicrobial resistance, appropriate antimicrobials are essential to optimise patient outcomes. In 2017, antimicrobial use prevalence (AMU) on the two neurosurgical wards in our tertiary teaching hospital varied from 23% on ward A to 33% on ward B with 67% and 100% ‘appropriate’ prescriptions, respectively. In July 2018, a weekly antimicrobial stewardship multidisciplinary round led by a senior neurosurgery registrar commenced, attended by the antimicrobial stewardship team (AST).

Research question

This report evaluates whether a multi-disciplinary approach on neurosurgical prescribing was beneficial, specifically in reducing AMU.

Materials and methods

The following data was collected on AST rounds for 30 weeks in total from August 2018 to July 2019: number of patients on antimicrobials, appropriateness and stewardship actions. A questionnaire was distributed to neurosurgical doctors on two occasions to canvass opinions and attitudes on antimicrobial prescribing.

Results

1716 prescriptions were reviewed (mean 57.2 per week). Of these 321 (18.7%) included antimicrobial prescriptions; 200 on ward A (19.8%), and 121 on ward B (17%), representing a decrease in AMU from 2017. The majority of antimicrobial prescriptions, 271 (84.4%) were deemed appropriate. Stewardship actions were taken in 215 (67%) prescriptions.

Fifteen questionnaires were completed by neurosurgical doctors. The majority, 87%, stated the AST round was helpful overall. 93% indicated that informal training on the AST round was a source of education in antibiotic prescribing.

Discussion and conclusion

The weekly AST round provided a timely opportunity for multidisciplinary discussion, implementation of antimicrobial stewardship actions and opportunistic antimicrobial stewardship education.

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Surgeons need to be directly involved in antimicrobial stewardship to optimise patient outcomes and reduce antimicrobial resistance.

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A multidisciplinary antimicrobial stewardship (AST) ward round led by neurosurgery commenced in our hospital in 2018.

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Antimicrobial stewardship actions were taken in 67% of prescriptions, and antimicrobial use prevalence reduced in 2018 compared to 2017.

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A questionnaire distributed to neurosurgical doctors on the value of the AST round indicated that 87% of neurosurgical doctors found it helpful.

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We ​believe leadership and accountability were crucial to the success of the ward round, as neurosurgeons contributed directly to decision making.

Spontaneous Escherichia coli Meningitis and Pyogenic Ventriculitis in an Adult Receiving Anti-Tumour Necrosis Factor Alpha Therapy

Presentation A 60-year-old male taking etanercept for ankylosing spondylitis was admitted to hospital with confusion and reduced level of consciousness over the preceding 24 hours. Diagnosis Magnetic Resonance Imaging (MRI) of his brain revealed pyogenic ventriculitis, and Escherichia coli was cultured from CSF. Treatment He required placement of an external ventricular drain and was treated with a prolonged course of intravenous ceftriaxone. Conclusion To our knowledge, this is the first reported case of spontaneous Gram-negative bacillary meningitis in a patient on anti-tumour necrosis factor (TNF)-alpha therapy, highlighting the risk of rare but serious infections associated with this class of medication.