Robert H. Pudenz (1911-1998) and Ventriculoatrial Shunt: Historical Perspective

Ventriculoatrial Shunt Versus Ventriculoperitoneal Shunt: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

Ventriculoperitoneal shunt (VPS) is usually the primary choice for cerebrospinal fluid shunting for most neurosurgeons, while ventriculoatrial shunt (VAS) is a second-line procedure because of historical complications. Remarkably, there is no robust evidence claiming the superiority of VPS over VAS. Thus, we aimed to compare both procedures through a meta-analysis.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, the authors systematically searched the literature for articles comparing VAS with VPS. The included articles had to detail one of the following outcomes: revisions, infections, shunt-related mortality, or complications. In addition, the cohort for each shunt model had to encompass more than 4 patients.

RESULTS

Of 1872 articles, 16 met our criteria, involving 4304 patients, with 1619 undergoing VAS and 2685 receiving VPS placement. Analysis of revision surgeries showed no significant difference between VAS and VPS (risk ratio [RR] = 1.10, 95% CI: 0.9-1.34; I2 = 84%, random effects). Regarding infections, the analysis also found no significant difference between the groups (RR = 0.67, 95% CI: 0.36-1.25; I2 = 74%, random effects). There was no statistically significant disparity between both methods concerning shunt-related deaths (RR = 2.11, 95% CI: 0.68-6.60; I2 = 56%, random effects). Included studies after 2000 showed no VAS led to cardiopulmonary complications, and only 1 shunt-related death could be identified.

CONCLUSION

Both methods show no significant differences in procedure revisions, infections, and shunt-related mortality. The literature is outdated, research in adults is lacking, and future randomized studies are crucial to understand the profile of VAS when comparing it with VPS. The final decision on which distal site for cerebrospinal shunting to use should be based on the patient's characteristics and the surgeon's expertise.

Incidence and nature of complications associated with ventriculoatrial shunt placement: A systematic review and single-arm meta-analysis

BACKGROUND

Ventriculoatrial shunt (VAS) is considered the second option for treating hydrocephalus, but there remains a lack of robust evidence regarding its complications profile.

PURPOSE

Evaluate the complications associated with VAS.

METHODS

Adhering to PRISMA guidelines, the authors searched Embase, PubMed, and Web of Science databases to identify articles reporting on the complications of VAS. Eligible articles were required to report whether complications occurred in a cohort of at least four patients. The extraction process focused on various outcome measures, including overall complications, pulmonary complications, cardiac complications, mortality, shunt revisions, glomerulonephritis, intracranial hemorrhage, and hygroma. Complications were defined as any adverse events related to the procedure, including revisions.

RESULTS

After retrieving a total of 2828 articles, 53 studies met the predefined criteria, involving 2862 patients. The overall complication rate was estimated at 33 % (95 % CI: 25-42 %), while the long-term complications rate was found to be 49 % (95 % CI: 32-67 %). Among the pediatric population, the complication rate was calculated to be 53 % (95 % CI: 39-68 %). The overall revision rate was estimated at 32 % (95 % CI: 23-41 %), with an infection rate of 5 % (95 % CI: 3-7 %). Notably, in the pediatric group, the infection rate was 10 % (95 % CI: 6-13 %). The random analysis indicated an estimated risk of 0 % for glomerulonephritis, intracranial hemorrhage, hygroma, cardiac complications, pulmonary complications, and shunt-related mortality.

CONCLUSION

VAS is a safe alternative when ventriculoperitoneal shunting is not feasible. Risk of classic severe complications is minimal. Nevertheless, caution is required when shunting critical patients. Further randomized studies are warranted to establish the ideal shunt for different patients.

Shunt technology for infants and a lifetime

The use of cerebrospinal fluid (CSF) shunts remains a fundamental therapeutic modality in the management of hydrocephalus. Nowadays, neurosurgeons have an arsenal of different shunt technologies on their hands, with several companies producing many different configurations of them. The greatest difficulty of treating a child with hydrocephalus is to deal with a brain that will enormously change its size and hydrodynamic conditions and a body that will multiply its height and weight in a short time. Detailed knowledge of the hydrodynamic properties of shunts is mandatory for any neurosurgeon and much more for those taking care of pediatric patients. It is necessary to know that these properties of the valve may influence the evolution of the patient after shunting and it is recognized that a patient physiology-specific valve selection may yield better outcomes and decrease complications. This article provides a summary of the most common available CSF valves and overdrainage control devices, their technology, and possible combinations. The objective is to offer a quick overview of the armamentarium to facilitate the recognition of the implanted device and improve the selection of the most suitable valve for each patient.

Thrombosis associated with ventriculoatrial shunts

Ventriculoatrial shunts are the most common second-line procedure for cases in which ventriculoperitoneal shunts are unsuitable. Shunting-associated thrombosis is a potentially life-threatening complication after ventriculoatrial shunt insertion. The overall prevalence of this complication is still controversial because of substantial differences in the numbers found in studies using clinical data and in those analyzing postmortem findings. The etiology of thrombosis may be multifactorial, including shunt catheter itself, contents of cerebrospinal fluid, shunt infection, and genetic disorder. The clinical presentation can vary widely, ranging from asymptomatic to a life-threatening condition. Timely recognition of thromboembolic lesions is critical for treatment. However, early diagnosis and management is still challenging because of a relatively long asymptomatic latency and lack of clear guideline recommendations. The purpose of this review is to provide an overview of ventriculoatrial shunt thrombosis, especially to focus on its etiopathogenesis, diagnosis, treatment, and prevention.

Ventriculoatrial Shunting: An Escape Option in Patients with Idiopathic Normal Pressure Hydrocephalus Failing Ventriculoperitoneal Drainage

BACKGROUND

Ventriculoperitoneal (VP) shunting is widely accepted as the gold-standard treatment for idiopathic normal pressure hydrocephalus (iNPH). However, a restricted group of patients experience only minimal or no improvement after the operation. In such cases, the question whether the diagnosis was incorrect or the shunt is malfunctioning remains unanswered.

METHODS

We retrospectively collected data on a 10-year series of VP-shunted patients with iNPH showing transient or minimal improvement of symptoms within 3 weeks from surgery. A full workup (including noninvasive diagnostic, cognitive, and invasive tests) was performed. After ruling out mechanical malfunction, we performed a tap test followed by a Katzman test 2 weeks later. The confirmed persistence of disturbance of cerebrospinal fluid dynamics was treated by shunt revision and, if found working, by its replacement into the atrial cavity.

RESULTS

Twenty patients were diagnosed with shunt insufficiency. At surgery, the distal end of the shunt was easily extruded and found working in all cases. It was then repositioned into the right atrium (the first 8 patients of the series also underwent failed contralateral abdominal replacement). Early postoperative clinical improvement was always confirmed. In 1 case, shunt overdrainage was corrected by valve upregulation.

CONCLUSIONS

According to our experience, inadequate distal end placement of a shunt might be one of the reasons needing investigation in patients with iNPH failing improvement after surgery. In such situations, the conversion to a ventriculoatrial shunt proved to be a low-cost and successful treatment option.

Technical Nuances of Ventriculoatrial Shunt Using Seldinger Technique for Percutaneous Insertion of Distal Shunt Catheter

Introduction One of the most seen neurosurgical complications is the ventriculoperitoneal (VP) shunt failure. The cause can be often due to peritoneal malabsorption of cerebrospinal fluid. The next safer alternative is to place a ventriculoatrial (VA) shunt. Various methods of access to the right atrium had been described. The percutaneous method of insertion of distal catheter using Seldinger technique is a safer alternative to open method. We describe the percutaneous insertion of distal catheter using Seldinger technique, modifications in the method, and specific tools required for the insertion.

Clinical History The patient is a 22-year-old male who is a known case of tubercular meningitis with recurrent failure of VP shunt due to malabsorption at peritoneal end of catheter. During the last hospital visit, he presented with altered sensorium and computed tomography scan brain showed ventriculomegaly. He was planned for VA shunt placement.

Surgical Technique The insertion of ventricular end of the catheter is similar to any other shunt placement. The internal jugular vein (IJV) was punctured using introducer needle and guide wire was placed in the IJV at the level of T6-T7 and the serial dilators passed on the guide wire for creating a track for passage of shunt catheter. The shunt catheter was passed over the guide wire to the desired vertebral level and distal shunt catheter is connected proximally to the shunt catheter in the neck.

Conclusion The percutaneous insertion of distal catheter with serial dilators using Seldinger technique is a safe and effective method for VA shunt placement.

Inflammation and obstruction of distal catheter slits in ventriculoperitoneal shunts: likely role of graphite

OBJECTIVE

Tissue reactions that contribute to obstruction of peritoneal catheters in ventriculoperitoneal shunt systems are not well characterized. Several recent rapid obstructions in children prompted a retrospective quality assurance review.

METHODS

The authors conducted a detailed investigation of 22 surgically explanted peritoneal shunt catheters and 8 autopsy cases with documented distal shunt obstruction. Patients' medical histories were reviewed, and the catheters and/or tissues were subjected to conventional histological and immunohistochemical evaluations. In addition, 3 cases were subjected to electron microscopic examination including elemental analysis.

RESULTS

The majority of symptomatic obstructions were associated with distal slit catheters (17 slit, 3 open-end, and 2 unknown type). Among the autopsy cases, deaths were attributed to shunt failure in 2 cases of slit catheter obstruction, 1 case of open-end catheter obstruction, and 1 case of catheter withdrawal from the peritoneal cavity. The early tissue response consisted of a predominantly T lymphocyte accumulation with phagocytosis of graphite particles by macrophages. This is associated with proliferation of fibroblasts, mesothelial cells, and blood vessels, which can grow through the slits and occlude the catheter lumen. As the inflammation subsides after approximately 1 year, the tissue plug becomes collagenized and calcified.

CONCLUSIONS

This study, supported by experimental literature in other organ systems, indicates that graphite used to coat the slit openings of distal catheters from ventriculoperitoneal shunts likely predisposes to obstruction. Neurosurgeons and manufacturers should consider the potential negative consequences of this shunt design. The authors concur with previous recommendations that slit-valve distal catheters should not be used for ventriculoperitoneal shunting unless they can be proven safe and efficacious in a controlled trial.

Distal Ventriculoatrial Shunt Revision in Adult Myelomeningocele Patient Performed via Endovascular Transvenous Approach

BACKGROUND

Myelomeningocele patients with shunt-dependent hydrocephalus often require multiple shunt revisions, eventually exhausting first-line distal diversion sites. Ventriculoatrial (VA) shunts are used less commonly than ventriculoperitoneal shunts, but knowledge of their use and complications is important to the neurosurgeon's armamentarium. VA shunts differ from ventriculoperitoneal and ventriculopleural shunts in that the ideal distal catheter target is an anatomically small area in comparison with the peritoneal and pleural cavities.

CASE DESCRIPTION

Here we present a case of an adult myelomeningocele patient who experienced migration of a distal VA shunt catheter. A minimally invasive revision technique that does not require recannulation of the vessels or open manipulation of the shunt is presented.

CONCLUSIONS

This is the fourth reported instance of successful distal revision of a migrated VA shunt catheter via transfemoral endovascular snaring. Knowledge of the opportunities afforded by this technique and collaboration with thoracic surgery colleagues is of benefit to all neurosurgeons.