The Role of Gut and Oral Microbiota in the Formation and Rupture of Intracranial Aneurysms: A Literature Review

In recent years, there has been a growing interest in the role of the microbiome in cardiovascular and cerebrovascular diseases. Emerging research highlights the potential role of the microbiome in intracranial aneurysm (IA) formation and rupture, particularly in relation to inflammation. In this review, we aim to explore the existing literature regarding the influence of the gut and oral microbiome on IA formation and rupture. In the first section, we provide background information, elucidating the connection between inflammation and aneurysm formation and presenting potential mechanisms of gut-brain interaction. Additionally, we explain the methods for microbiome analysis. The second section reviews existing studies that investigate the relationship between the gut and oral microbiome and IAs. We conclude with a prospective overview, highlighting the extent to which the microbiome is already therapeutically utilized in other fields. Furthermore, we address the challenges associated with the context of IAs that still need to be overcome.

The impact of intraoperative MRI on cranial surgical site infections-a single-center analysis

PURPOSE

The use of intraoperative MRI (ioMRI) contributes to an improved extent of resection. Hybrid operating room MRI suites have been established, with the patient being transferred to the MRI scanner. In the present descriptive analysis, we compared the rate of surgical site infections (SSI) after intracranial tumor surgery with and without the use of ioMRI.

METHODS

In this retrospective study, we included 446 patients with open craniotomy performed for brain tumor surgery. One hundred fourteen patients were operated on with the use of ioMRI between June 1, 2018, and June 30, 2019 (group 1). During the same period, 126 patients were operated on without ioMRI (group 2). As an additional control group, we analyzed 206 patients operated on from February 1, 2017, to February 28, 2018 when ioMRI had not yet been implemented (group 3).

RESULTS

The rate of SSI in group 1 (11.4%), group 2 (9.5%), and group 3 (6.8%) did not differ significantly (p = 0.352). Additional resection after ioMRI did not result in a significantly elevated number of SSI. No significant influence of re-resection, prior radio-/chemotherapy, blood loss or duration of surgery was found on the incidence of SSI.

CONCLUSION

Despite the transfer to a non-sterile MRI scanner, leading to a prolonged operation time, SSI rates with and without the use of ioMRI did not differ significantly. Hence, advantages of ioMRI outweigh potential disadvantages as confirmed by this real-life single-center study.

Surgery in Acute Metastatic Spinal Cord Compression: Timing and Functional Outcome

Simple Summary

Spinal metastases affect an exceptionally high number of cancer patients and thereby represent a common challenge for healthcare providers. Patients may suffer from debilitating symptoms, including excruciating back pain, immobility and even neurological dysfunction. An exceptionally acute clinical presentation is caused by the compression of the spinal cord through growth of a spinal metastasis within the spinal canal, which may leave the patient with acute spinal cord injury in need of rapid surgical treatment. In clinical practice and science, no true timeframe has yet been defined within which these patients need to undergo surgery, although it is generally understood that their recovery and functional rehabilitation correlate with the time to surgery after symptom onset. In our study, we analyzed a surgically treated cohort of patients with acute spinal cord injury by metastatic compression to investigate the correlation of the timing of surgery with neurological recovery. We were able to identify a subgroup of patients with significantly improved recovery, in whom surgery was initiated within 16 h after admission. Complication rates were not significantly more frequent in this subgroup compared to patients operated on after 16 h. Based on these findings, we conclude that striving for surgery as early as feasible is a warranted strategy in patients with acute neurological deterioration due to metastatic spinal cord compression.

Abstract

Background: Patients with metastatic spinal cord compression (MSCC) may experience long-term functional impairment. It has been established that surgical decompression improves neurological outcomes, but the effect of early surgery remains uncertain. Our objective was to evaluate the impact of early versus late surgery for acute MSCC due to spinal metastases (SM). Methods: We retrospectively reviewed a consecutive cohort of all patients undergoing surgery for SMs at our institution. We determined the prevalence of acute MSCC; the time between acute neurological deterioration as well as between admission and surgery (standard procedure: decompression and instrumentation); and neurological impairment graded by the ASIA scale upon presentation and discharge. Results: We screened 693 patients with surgery for spinal metastasis; 140 patients (21.7%) had acute MSCC, defined as neurological impairment corresponding to ASIA grade D or lower, acquired within 72 h before admission. Non-MSCC patients had surgery for SM-related cauda equina syndrome, radiculopathy and/or spinal instability. Most common locations of the SM in acute MSCC were the thoracic (77.9%) and cervical (10.7%) spine. Per standard of care, acute MSCC patients underwent surgery including decompression and instrumentation, and the median time from admission to surgery was 16 h (interquartile range 10–22 h). Within the group of patients with acute MSCC, those who underwent early surgery (i.e., before the median 16 h) had a significantly higher rate of ASIA improvement by at least one grade at discharge (26.5%) compared to those who had late surgery after 16 h (10.1%; p = 0.024). Except for a significantly higher sepsis rate in the late surgery group, complication rates did not differ between the late and early surgery subgroups. Conclusions: We report data on the largest cohort of patients with MSCC to date. Early surgery is pivotal in acute MSCC, substantially increasing the chance for neurological improvement without increasing complication rates. We found no significant impact when surgery was performed later than 24 h after admission. These findings will provide the framework for a much-needed prospective study. Until then, the treatment strategy should entail the earliest possible surgical intervention.

Cement-Augmented Carbon Fiber-Reinforced Pedicle Screw Instrumentation for Spinal Metastases: Safety and Efficacy

OBJECTIVE

To investigate the complication rates and long-term implant failure rates in a monocentric study of a consecutive cohort of patients with thoracolumbar spinal metastases after posterior instrumentation with a fenestrated carbon fiber-reinforced poly-ether-ether-ketone (CFRP) pedicle screw system.

METHODS

We retrospectively reviewed demographics, Karnofsky Performance Status Scale scores, complications, and implant failure rates.

RESULTS

Between June 2016 and November 2019, 51 consecutive patients underwent cement-augmented CFRP pedicle screw instrumentation at our institution. Mean age was 68 years (standard deviation 10.5), the median preoperative Karnofsky Performance Status Scale of 80 increased to 90 postoperatively (P = 0.471). Most common primary entities were breast (25.5%), lung (15.7%), and prostate (13.7%) cancers. Of 428 placed screws, 293 (68.5%) were augmented with polymethylmethacrylate, a mean 6 per patient (standard deviation ±2). Screws were inserted via a minimally invasive system technique in 54.9% of cases. In total, 11.8% of patients had immediate postoperative sequelae related to the cement. Pulmonary cement embolisms were noted in 3 patients, 2 had paravertebral extravasation, and 1 had an embolism into a segmental artery. Of these 6, 2 patients with pulmonary embolisms reported related symptoms. Follow-up was available for 80.4%. After a mean 9.8 months, screw loosening was noted in 11.8% of cases on computed tomography, although it was asymptomatic in all but 1 patient. Screw pull-out did not occur. Neither cement-related (P = 0.353) nor general complication rates (P = 0.507) differed significantly between open and minimally invasive system techniques.

CONCLUSIONS

Percutaneous cement-augmented CFRP pedicle screw instrumentation facilitates artifact-reduced postoperative imaging, while maintaining a risk profile and implant failure rates comparable to conventional metallic instrumentation.

Comprehensive surgical treatment strategy for spinal metastases

The management of patients with spinal metastases (SM) requires a multidisciplinary team of specialists involved in oncological care. Surgical management has evolved significantly over the recent years, which warrants reevaluation of its role in the oncological treatment concept. Any patient with a SM was screened for study inclusion. We report baseline characteristics, surgical procedures, complication rates, functional status and outcome of a large consecutive cohort undergoing surgical treatment according to an algorithm. 667 patients underwent 989 surgeries with a mean age of 65 years (min/max 20–94) between 2007 and 2018. The primary cancers mostly originated from the prostate (21.7%), breast (15.9%) and lung (10.0%). Surgical treatment consisted of dorsoventral stabilization in 69.5%, decompression without instrumentation in 12.5% and kyphoplasty in 18.0%. Overall survival reached 18.4 months (95% CI 9.8–26.9) and the median KPS increased by 10 within hospital stay. Surgical management of SMs should generally represent the first step of a conclusive treatment algorithm. The need to preserve long-term symptom control and biomechanical stability requires a surgical strategy currently not supported by level I evidence.

Low-Grade Infection and Implant Failure Following Spinal Instrumentation: A Prospective Comparative Study

BACKGROUND

Spinal instrumentation can be associated with complications, including implant loosening. Hitherto, implant loosening has mainly been attributed to mechanical overload.

OBJECTIVE

To examine the role of low-grade infections as the cause of implant failure in suspected aseptic implant loosening following spinal instrumentation.

METHODS

A prospective single center observational study was performed. All patients who had revision surgery following spinal instrumentation between August 2015 and February 2018 were screened. Patients with revision surgery due to screw loosening on the computed tomograhy scan constituted the study group. Patients in which the screws where not loosened but removal was performed for other reasons formed the comparison group. Intraoperative swabs were taken and sonication was performed with the explanted material. Results of microbiological cultivation were analyzed.

RESULTS

A total of 59 patients were included in the study group and 34 in the comparison group. In the study group in 42.4% of the cultures a bacterium was detected, while in the comparison group only in 17.6%. 84%, and 83.3% of these germs were detected by sonication in the study and comparison group, respectively. The rate of positive cultures was significantly higher in the study group compared to the comparison group (P = .001). The most frequent bacterium cultivated in both groups was Propionibacterium acnes, followed by Staphylococcus species.

CONCLUSION

For patients with screw loosening a high level of suspicion for a low-grade infection should be raised. Cultures should be performed from the sonication fluid of the explanted devices in all patients with symptomatic screw loosening.

Psychological predictors of quality of life after anterior cervical discectomy and fusion for degenerative cervical spine disease

We aimed to identify independent psychological predictors of quality of life (QOL) and functional outcome after anterior cervical discectomy and fusion (ACDF) for degenerative cervical spine disease. We prospectively included patients undergoing ACDF for degenerative cervical disc herniation and stenosis. Patients completed a structured psychological assessment including the Center for Epidemiological Studies Depression Scale (ADS-K), Post-Traumatic Stress Scale-10 (PTSS-10), State Trait Anxiety Inventory-State Anxiety and - Trait Anxiety (STAI-S and STAI-T) and Anxiety Sensitivity Index-3 (ASI-3) before surgery, after 3 and 12 months. Outcome measures included EuroQol-5D (EQ), Short Form-36 (SF-36) and Oswestry Disability Index (ODI) scores. Of 104 included patients who underwent ACDF between March 2013 and November 2017, 92 completed follow-up after 3 and 12 months. The mean Visual Analogue Scale (VAS) scores for neck pain (− 1.4; p < .001) and arm pain (− 1.8; p = .031) significantly decreased by 12 months. QOL scores significantly increased by 3 months (EQ: + 0.2; p < .001; SF-36 PCS: + 6.2; p < .001; SF-36 MCS: + 2.5; p = .044), a benefit which was retained at 12 months. Linear regression analyses identified statistically significant predictors in preoperative ASI-3, SF-36 MCS and STAI-S for postoperative QOL and ODI scores. There is a benefit for patients in terms of quality of life and function after undergoing surgery for degenerative cervical spine disease. With the ASI-3, SF-36 MCS and STAI-S there exist some predictors for postoperative QOL and ODI scores.

Radiographic measurements of cervical alignment, fusion and subsidence after ACDF surgery and their impact on clinical outcome

BACKGROUND

Some recent studies indicate correlations between cervical alignment and clinical outcome after anterior cervical discectomy and fusion (ACDF) surgery. However, there still are no established criteria for the interpretation of alignment, fusion and subsidence in relation to clinical outcome.

METHODS

A retrospective analysis of 208 radiographs of patients following ACDF with stand-alone PEEK cage implantation was performed. The measurements were obtained on plain radiographs in lateral and anteroposterior projections as well as flexion/extension radiographs. Cervical alignment was measured using the Gore, Laing and Cobb methods; fusion was evaluated by an assortment of radiographic hallmarks: the presence of bridging bone, the Cobb angle and the distances between the tips and bases of the spinous processes of the operated segments, respectively. For assessment of subsidence, we used the Mochida method in addition to ventral and dorsal segmental height reduction. Correlation analysis between the different radiological characteristics and clinical outcome at a minimum follow-up of 12 months was conducted.

RESULTS

Two hundred and eight patients were evaluated for alignment, fusion and subsidence. Cervical alignment using the Gore and Cobb methods correlated among each other, but failed to exhibit significant correlation with clinical outcome. Interpretation of fusion rates varied greatly (43.9 to 89.4%) depending on the criteria used. Pearson coefficients between radiographic presence of pseudarthrosis and the measurements of the spinous process distances (0.595; p < 0.001), the Cobb angles (0.187; p = 0.007) and the presence of bridging bone (0.224; p < 0.001) each exhibited statistical significance. None of the methods employed significantly correlated with clinical outcome. Regarding subsidence, we found rates of 62%, 48% and 27% using the Mochida, ventral and dorsal segmental height reduction assessment methods, respectively. Pearson correlations between pairs of Mochida/ventral (r = 0.39; p = 0.66) and Mochida/dorsal (r = 0.007; p = 0.921) height reduction assessment methods were weak and no significant correlation between subsidence rates and clinical outcome was shown.

CONCLUSION

All measured parameters varied depending in the measurement method used. This was most pronounced for fusion. There was a moderate positive correlation between neck pain and subsidence as measured by the Mochida method.

The relevant psychological burden of having a benign brain tumor: a prospective study of patients undergoing surgical treatment of cranial meningiomas

OBJECTIVE

Meningiomas are the most common intracranial neoplasm. Evidence concerning surgical management and outcome is abundant, while the implications for the quality of life (QOL) of a patient confronted with the diagnosis and undergoing surgery are unclear. The authors conducted a prospective study to evaluate QOL in relation to psychological comorbidities comorbidities.

METHODS

A prospective study of patients undergoing elective surgery for the removal of an intracranial meningioma was performed. The authors evaluated depression (Allgemeine Depressionsskala K score) and anxiety (Post-Traumatic Stress Scale–10 [PTSS-10]; State Trait Anxiety Inventory–State Anxiety and –Trait Anxiety [STAI-S and STAI-T]; and Anxiety Sensitivity Index–3 [ASI-3]) scores before surgery and at 3 and 12 months after surgery. The correlation between preoperative psychological burden and postoperative QOL as measured by the 36-Item Short Form Health Survey and EQ-5L questionnaires was analyzed. Incidence and influence of these psychiatric comorbidities on clinical outcome were examined.

RESULTS

A total of 78 patients undergoing resection of a meningioma between January 2013 and September 2017 participated in the preoperative psychological screening and 71 patients fully completed postoperative follow-up examination after 1 year of follow-up. At presentation, 48 patients (67.7%) had abnormal anxiety scores, which decreased to 29.6% (p = 0.003). On follow-up at 12 months, mean EQ-5L visual analog scale scores were significantly lower in patients with pathological scores on the PTSS-10 (0.84 vs 0.69; p = 0.004), STAI-S (0.86 vs 0.68; p = 0.001), and STAI-T (0.85 vs 0.71; p = 0.011). Neurological status (modified Rankin Scale) improved slightly and showed some correlation with psychological comorbidities QOL scores (p = 0.167). There was a nonsignificant increase of EQ-5L scores over the period of follow-up (p = 0.174) in the repeated-measures analysis. In the regression analysis, impaired QOL and physical disability on follow-up correlated with elevated preoperative anxiety and depression levels.

CONCLUSIONS

The QOL and physical disability of patients undergoing resection of an intracranial meningioma highly depend on preoperative anxiety and depression levels. Stress and anxiety scores generally decrease after the resection, which leads us to conclude that there is a tremendous emotional burden caused by an upcoming surgery, necessitating close psychooncological support in order to uphold functional outcome and health-related QOL in the postoperative course.