Hydrocephalus Shunt Type: A Comparative Meta-Analysis Of Safety And Efficacy
Since the inaugural hydrocephalus shunt in 1956, the ventriculoperitoneal shunt (VPS) has emerged as the primary surgical intervention for cerebrospinal fluid (CSF) diversion in North America and Europe. Despite its effectiveness, VPS entails risks such as brain hemorrhages, damage, infections, and high revision rates. In contrast, the lumbar-peritoneal shunt (LPS) has gained traction as an alternative for idiopathic normal pressure hydrocephalus (iNPH), particularly in Japan. This study conducts a systematic review and meta-analysis to compare the safety, adverse effects, and outcomes of LPS and VPS in communicating hydrocephalus patients, addressing a shortage of comparative data.
THE BACKGROUND OF THE STUDY
Hydrocephalus, a condition characterized by an abnormal accumulation of cerebrospinal fluid (CSF) within the brain, has been the subject of significant medical advancements since the introduction of the first hydrocephalus shunt in 1956 [1]. The ventriculoperitoneal shunt (VPS) has since become the standard surgical treatment for CSF diversion, particularly in North America and Europe, due to its effectiveness in providing immediate symptomatic relief [1][2]. However, the use of VPS is associated with notable complications, including intracranial placement-related issues such as brain hemorrhages, damage, infections, and a high risk of revision [3].
In contrast, the lumbar-peritoneal shunt (LPS) has emerged as an alternative for patients with communicating hydrocephalus, offering a potential solution to mitigate risks such as brain damage and the need for extracranial access [5]. LPS has gained prominence as the preferred treatment for idiopathic normal pressure hydrocephalus (iNPH) in Japan, showcasing its growing importance in hydrocephalus management [6][7]. Despite its availability for over six decades, LPS has not achieved the same status as VPS in other regions.
Given the limited comparative studies on the safety, adverse effects, and outcomes of LPS and VPS, this research conducts a systematic review and meta-analysis to address this knowledge gap. The study aims to provide valuable insights into these two surgical interventions’ relative merits and risks for communicating hydrocephalus, offering a comprehensive understanding of their clinical and radiological implications [8].
THE STUDY METHOD
The meta-analysis adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. The study included a diverse range of study designs, encompassing randomized controlled trials (RCTs), non-RCTs, and retrospective studies due to the scarcity of available RCTs. A comprehensive search strategy was implemented across multiple databases, including the Cochrane Library, PubMed, Embase, ClinicalTrials.gov, Cochrane Central Register of Controlled Trials, WanFang database, and the China National Knowledge Infrastructure database. Two independent reviewers searched and identified additional potential studies through reference lists and gray literature sources.
Inclusion criteria encompassed studies directly comparing ventriculoperitoneal shunt (VPS) and lumbar-peritoneal shunt (LPS), focusing on communicating hydrocephalus. Primary outcomes included treatment failure and adverse events, while secondary outcomes involved neurological disability improvement and radiological assessments. Two reviewers performed Data extraction and management independently, utilizing data collection forms tailored to the study.
ANALYSIS
The research employed Trial Sequential Analysis (TSA) to assess the statistical reliability of accumulated data through iterative testing. The analysis was conducted using TSA software and utilized a model with Type I and Type II errors set at 5% and 20%, respectively. O’Brien-Fleming monitoring boundaries were applied for hypothesis testing. In this approach, the cumulative effect was deemed positive if the Z-curve crossed the monitoring boundaries and negative if it entered the futility area. Notably, the underpowered total sample size fell short of the required information size. The incidences of the intervention and control arms were determined from all enrolled studies. Additionally, the certainty of evidence in the randomized controlled trial subgroups was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. This evaluation considered five downgrading and three upgrading domains, ultimately classifying the overall certainty of evidence as high, moderate, low, or very low.
RESULTS
Study Selection:
– 25 studies were included from an initial pool of 531 articles.
Included Studies:
– A mix of 3 RCTs, one prospective, and 20 retrospective studies on communicating hydrocephalus.
Key Findings:
– Lumbar-peritoneal shunt (LPS) had fewer complications than ventriculoperitoneal shunt (VPS).
– Odds ratio for complications: 0.29 (LPS better, p < 0.0001).
RCT Subgroup:
– LPS showed lower complication rates (14.81%) than VPS (39.81%).
– The odds ratio for RCT complications is 0.23 (LPS better, p < 0.0001).
Outcomes:
– LPS had fewer issues like shunt problems, infections, seizures, and hemorrhages.
Bias and Publication:
– Some concerns in RCTs, varied risk in non-randomized studies.
– Possible publication bias in certain outcomes.
Trial Sequential Analysis (TSA):
– Suggests LPS is better for complications but inconclusive due to the small sample size.
– Some analyses did not meet conventional boundaries.
In conclusion, a Lumbar-peritoneal shunt (LPS) may be preferable for treating communicating hydrocephalus, showing fewer complications compared to a Ventriculoperitoneal shunt (VPS).
DISCUSSION
The meta-analysis comparing lumbar-peritoneal shunt (LPS) and ventriculoperitoneal shunt (VPS) in communicating hydrocephalus patients reveals that LPS implantation is associated with lower adverse effects without compromising efficacy [1,8-15].
Contrary to the initial hypothesis, LPS and VPS exhibit similar safety and effectiveness overall. However, LPS demonstrates superiority in complications, including infections, seizures, shunt obstructions, and hemorrhages. The RCT subgroup analysis corroborates these findings, favoring LPS with lower total complication rates. Notably, this study marks the first to demonstrate decreased complications in LPS-treated patients, reporting total complication rates of 12.98% for LPS and 23.80% for VPS, aligning with previous VPS complication rates [1,8-15].
Specifically, LPS presents lower infection rates (1.53%) and shunt obstruction/malfunction rates (3.99%) than VPS. The absence of intracranial access during LPS implantation may contribute to a reduced risk of intraparenchymal hemorrhage, evidenced by a significantly lower hemorrhage rate (2.40%) than VPS (5.03%). Seizure rates are also higher in VPS, potentially related to complications during subcutaneous tunneling [1,8-15].
The lumbar exit and peritoneal entry at the same level during upright positioning in LPS minimize the siphoning effect, offering an advantage over VPS. Radiological improvements, reported inconsistently across studies, show a significantly better outcome for LPS, suggesting increased compatibility with cerebrospinal fluid dynamics. Despite these positive outcomes, the discussion acknowledges methodological limitations, emphasizing further research to validate the results, particularly in idiopathic normal pressure hydrocephalus (iNPH) [1,8-15].
Studies supporting the safety and efficacy of LPS in iNPH reinforce its viability as a treatment option. The meta-analysis provides valuable insights that challenge existing notions and advocate for reconsidering treatment approaches, especially in light of the observed benefits of LPS implantation [1,8-15].
LIMITATIONS OF THE STUDY
The study acknowledges several limitations that may impact the robustness of its findings. These limitations include:
- Study Design Heterogeneity: Most studies included in the meta-analysis were retrospective, non-randomized trials, potentially introducing bias. Despite three randomized controlled trials (RCTs), the small participant numbers and low event rates in these trials limit the study’s strength.
- Idiopathic and Secondary Hydrocephalus: The analysis did not differentiate between idiopathic and secondary communicating hydrocephalus, potentially leading to varied outcomes that were not separately addressed.
- Valve Type Variation: The study did not conduct a detailed analysis of different valve types, including programmable and more flexible systems. This lack of distinction could have implications for understanding complications associated with specific valve characteristics.
- Geographic and Ethnic Bias: Most studies, including all RCTs, were conducted in Asia, with a predominantly Asian participant population. This lack of ethnic diversity may limit the generalizability of the findings to a broader demographic.
- Hospital Protocol Differences: Including studies from different hospitals introduces potential bias, as varied protocols for VPS and LPS surgeries may influence outcomes.
- Overdrainage Not Adequately Addressed: The study should have thoroughly discussed overdrainage, a crucial complication. Only a few studies mentioned overdrainage and their ambiguous definitions and categorizations precluded meaningful pooling of this data.
- GRADE Evaluation: The study results received low and very low Certainty of Evidence (CoE) ratings according to the GRADE methodology, emphasizing the need for more high-quality studies to enhance confidence in the findings.
In conclusion, while the meta-analysis provides valuable insights, these limitations underscore caution in interpreting the results, emphasizing the need for more diverse, well-designed studies to strengthen the evidence base.
CONCLUSION
The meta-analysis findings suggest that the Lumboperitoneal Shunt (LPS) is a safe and equally effective treatment option for hydrocephalus compared to the Ventriculoperitoneal Shunt (VPS). LPS exhibited a lower overall complication rate, encompassing reduced infection, seizures, shunt obstruction/malfunction, and bleeding when contrasted with VPS. Pending further confirmation from additional high-quality studies, these results propose the potential of LPS to serve as a viable alternative or even a primary treatment choice for individuals with communicating hydrocephalus, particularly those not suitable for VPS. It highlights the clinical promise of LPS in advancing hydrocephalus management.
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