Diagnosis of Enterococcus faecalis meningitis associated with long-term cerebrospinal fluid rhinorrhoea using metagenomics next-generation sequencing: a case report

Background Enterococcus faecalis (E. faecalis) meningitis is a rare disease, and most of its occurrences are of post-operative origin. Its rapid diagnosis is critical for effective clinical management. Currently, the diagnosis is focused on cerebrospinal fluid (CSF) culture, but this is quite limited. By comparison, metagenomic next-generation sequencing (mNGS) can overcome the deficiencies of conventional diagnostic approaches. To our knowledge, mNGS analysis of the CSF in the diagnosis of E. faecalis meningitis has been not reported. Case presentation We report the case of E. faecalis meningitis in a 70-year-old female patient without a preceding history of head injury or surgery, but with an occult sphenoid sinus bone defect. Enterococcus faecalis meningitis was diagnosed using mNGS of CSF, and she recovered satisfactorily following treatment with appropriate antibiotics and surgical repair of the skull bone defect. Conclusions Non-post-traumatic or post-surgical E. faecalis meningitis can occur in the presence of occult defects in the cranium, and mNGS technology could be helpful in diagnosis in the absence of a positive CSF culture.

Cranioplasty: Surgical Research

Background: Cranioplasty involves the repair of a cranial defect or deformation for cosmetic reasons, as well as long-term protection of the brain from the external environment. This work aims to evaluate and compare the efficacy, advantages and limitations of different materials used in cranioplasty. Methods: Prospective study of twenty-five patients who underwent cranioplasty for a skull bone defect by using different materials from March 2018 to March 2020. Results: The study included 13 males and 12 females. The defect was post-traumatic in 11 patient neoplastic in 13 patients and 1 patient was after decompressive craniectomy for malignant ischemia .When the defect was less than 80 cm² bone cement was used in 54.5%. When the defect was ≥ 80 cm² titanium mesh was used in 71.4 % of those cases. 72.0% of the patients (18 of 25) reported excellent cosmetic results, 24% (6 of 25) good, 4.0% (1 of 25) poor results. Conclusion: When the original bone flap is not available for cranioplasty titanium mesh is suitable for the large calverial bone defects. it is strong but hard to shape while bone cement is more suitable for small defects near the skull base as it is easy to shape but weak. Medpore and hydroxyapetite powder are better for pediatric defects as they don't hinder bone growth. Prefabricated bone flaps are effective but expensive and can't be used if cranioplasty is planned in the same operation.

Clinical Efficacy and Safety of Silicone Elastomer Sheet during Decompressive Craniectomy: Anti-Adhesive Role in Cranioplasty

(1) Background: Cranioplasty is a surgery to repair a skull bone defect after decompressive craniectomy (DC). If the process of dissection of the epidural adhesion tissue is not performed properly, it can cause many complications. We reviewed the effect of a silicone elastomer sheet designed to prevent adhesion. (2) Methods: We retrospectively reviewed 81 consecutive patients who underwent DC and subsequent cranioplasty at our institution between January 2015 and December 2019. We then divided the patients into two groups, one not using the silicone elastomer sheet (n = 50) and the other using the silicone elastomer sheet (n = 31), and compared the surgical outcomes. (3) Results: We found that the use of the sheet shortened the operation time by 24% and reduced the estimated blood loss (EBL) by 43% compared to the control group. Moreover, the complication rate of epidural fluid collection (EFC) in the group using the sheet was 16.7%, which was lower than that in the control group (41.7%, p < 0.023). Multivariate logistic regression analysis showed the sheet (OR 0.294, 95% CI 0.093–0.934, p = 0.039) to be significantly related to EFC. (4) Conclusions: The technique using the silicone elastomer sheet allows surgeons to easily dissect the surgical plane during cranioplasty, which shortens the operation time, reduces EBL, and minimizes complications of EFC.

Effect of Honeycomb β-TCP Geometrical Structure on Bone Tissue Regeneration in Skull Defect

The effect of the geometric structure of artificial biomaterials on skull regeneration remains unclear. In a previous study, we succeeded in developing honeycomb β-tricalcium phosphate (β-TCP), which has through-and-through holes and is able to provide the optimum bone microenvironment for bone tissue regeneration. We demonstrated that β-TCP with 300-μm hole diameters induced vigorous bone formation. In the present study, we investigated how differences in hole directions of honeycomb β-TCP (horizontal or vertical holes) influence bone tissue regeneration in skull defects. Honeycomb β-TCP with vertical and horizontal holes was loaded with BMP-2 using Matrigel and Collagen gel as carriers, and transplanted into skull bone defect model rats. The results showed that in each four groups (Collagen alone group, Matrigel alone group, Collagen + BMP group and Matrigel + BMP-2), vigorous bone formation was observed on the vertical β-TCP compared with horizontal β-TCP. The osteogenic area was larger in the Matrigel groups (with and without BMP-2) than in the Collagen group (with and without BMP-2) in both vertical β-TCP and horizontal β-TCP. However, when BMP-2 was added, the bone formation area was not significantly different between the Collagen group and the Matrigel group in the vertical β-TCP. Histological finding showed that, in vertical honeycomb β-TCP, new bone formation extended to the upper part of the holes and was observed from the dura side to the periosteum side as added to the inner walls of the holes. Therefore, we can control efficient bone formation by creating a bone microenvironment provided by vertical honeycomb β-TCP. Vertical honeycomb β-TCP has the potential to be an excellent biomaterial for bone tissue regeneration in skull defects and is expected to have clinical applications.