This study was designed as a two-part investigation, comprising both retrospective and prospective components. The research was approved by the Ethics Committee of Ludwig-Maximilian University Munich.
We used the STROBE statement as a reporting guideline. 3
Study Design and Patient Selection
This study was designed as a combined retrospective and prospective analysis focusing on patients who underwent neurosurgical procedures involving semi-synthetic dural replacements. It was conducted in two distinct phases:
1. Retrospective Analysis (December 2022 - March 2023): This phase involved analyzing data from the last 30 patients who received semi-synthetic dural replacements during the specified period. Inclusion criteria were patients aged 18 and above who had undergone allogeneic dural replacement, with the primary exclusion criterion being a history of prior craniotomy.
2. Prospective Analysis (March 2023 - September 2023): The prospective phase involved the active enrollment and monitoring of 30 new patients undergoing similar procedures. The inclusion and exclusion criteria were consistent with those of the retrospective phase. This phase aimed to collect real-time data for a more current understanding of the outcomes.
Follow-Up Period
In both retrospective and prospective phases, patients were followed for a duration of 30 days post-surgery. This follow-up period was chosen to effectively monitor immediate and short-term postoperative outcomes, such as complications, recovery progress, and early signs of infection or inflammation.
Data Collection and Management
Data were comprehensively collected from patient medical records, surgical reports, and follow-up notes. Key information included:
- Demographic details of the patients
- Specifics of the neurosurgical procedures
- Immediate and short-term postoperative outcomes
- Follow-up data within the 30-day postoperative window
Surgical Approach and Procedure
The surgical approach in this study was meticulously designed to prioritize the integrity and functionality of the dural replacement. A key objective in each procedure was to achieve a watertight suture, critical for preventing cerebrospinal fluid (CSF) leakage and ensuring optimal patient outcomes.
Dural Suturing Technique:
- Each neurosurgical procedure involved careful handling of the semi-synthetic dural replacements.
- The primary aim during suturing was to establish a watertight seal. This was considered a critical step in the procedure, as a watertight suture significantly reduces the risk of CSF leakage and related complications.
- Surgeons were given the discretion to decide on the suturing technique. They could opt for a pure suture approach or enhance the suture line using additional materials like adhesive patches or fibrin glue. This flexibility allowed surgeons to tailor the procedure based on the specific surgical scenario and patient's condition.
Use of Adhesive Enhancements:
- In situations where additional security was deemed necessary, surgeons could employ adhesive patches or fibrin glue.
- The use of these materials was at the surgeon’s discretion and was based on factors like the size of the dural opening, the patient’s medical history, and intraoperative findings.
- These adhesive enhancements were applied to reinforce the suture line, ensuring a more robust and reliable seal.
Final Water Test:
- The culmination of the dural suturing process involved a critical water test.
- This test was conducted to ensure the suture's integrity and confirm its watertight nature.
- During the test, the surgical area was irrigated with sterile water, and the suture line was closely inspected for any sign of leakage.
- This step was mandatory for all procedures, serving as a quality control measure to verify the success of the suturing technique.
Endpoints
Primary Endpoint:
- Incidence of CSF leakage within the 30-day follow-up period.
Secondary Endpoints:
- Clinical assessments for signs of infection or inflammation during the follow-up.
- Radiographic evaluations within the follow-up period.
- Recovery and quality of life metrics assessed at the end of the 30-day follow-up.
Ethical Considerations:
The study was conducted in compliance with ethical standards, with approval from the relevant ethics committee. Patient confidentiality and data privacy were a top priority.
The study protocol was approved by the ethic committee of the Ludwig-Maximilian-University Munich (Bavaria / Germany) at 12.03.2023 with the ID: 22-1112.
Study Limitations:
Recognized limitations included potential selection bias, limited follow-up duration impacting the assessment of long-term outcomes, and non-randomized patient selection influencing results.
Study Design:
This research utilized a single-center study design to investigate the phenomenon under investigation. The decision to conduct a single-center study was based on logistical and resource constraints. While this design offers specific advantages, such as control over experimental conditions and consistent data collection protocols, it may limit the generalizability of the findings to a broader population.
Blinded Evaluation:
The evaluation of study outcomes was not conducted in a blinded manner. Due to practical considerations, the evaluators were aware of the treatment allocation for each participant during the data analysis phase. This lack of blinding introduces the potential for bias in the interpretation of the results. To minimize potential bias, we employed absolute analysis criteria (such as assessing whether the patient was alive or required re-operation). While blinding was not feasible in this study, efforts were made to minimize bias through rigorous data collection and analysis.
Non-simultaneous Treatment Allocation:
The treatment allocation for the study groups did not occur simultaneously. This may introduce confounding variables associated with temporal changes or external factors that could impact the outcomes of the study. While efforts were made to minimize these potential confounders through rigorous participant selection criteria and data analysis techniques, it is important to acknowledge the possibility of temporal influences on the observed results.
Statistical Analysis:
Comprehensive statistical methods were employed. Techniques included descriptive and inferential statistics to analyze patient outcomes during the 30-day follow-up period. Significance was set at p < 0.05.
The collected data were subjected to rigorous statistical analysis to examine the research hypotheses. Descriptive statistics, inferential tests (e.g., t-tests, chi-square tests), and regression analyses were conducted as appropriate based on the nature of the variables and research questions.
Statistical software (GraphPad PRISM 9; GraphPad Software Boston (MA) USA) was employed for data analysis, and the significance level was set at p < 0.05.
Values were reported using median and one standard deviation (+/- 1SD). We checked Gaussians distribution using the Shapiro-Wilk test. Statistical differences of metric variables (blood loss, duration of surgery, length of hospital stay) were calculated using either the Student´s t-test or the Wilcoxon test for paired samples and the Mann-Whitney-U test for unpaired samples.
Data Quality and Integrity:
Data quality and integrity were ensured through rigorous training of data collectors, double-data entry, and validation checks.