Treatment of recurrent ventriculoperitoneal shunt failure associated with persistent cerebrospinal fluid eosinophilia and latex allergy by use of an "extracted" shunt

Repeated shunt dysfunction due to Barium allergy that was difficult to differentiate from shunt infection

We encountered a case of repeated shunt dysfunction caused by barium allergy. The patient was a 60-year-old male who underwent ventricular peritoneal shunting for hydrocephalus following subarachnoid hemorrhage due to a ruptured aneurysm;however, it malfunctioned many times. A patch test performed after the third reconstruction was positive for barium. To the best of our knowledge, this is the first case report of shunt malfunction due to barium allergy. The patch test is useful in cases of suspected allergy-related dysfunction. We recommend the introduction of barium into antigen testing using the patch test. J. Med. Invest. 70 : 521-523, August, 2023.

A case series of hypersensitivity reactions to ventriculoperitoneal shunt material

Hypersensitivity reactions to ventriculoperitoneal (VP) or lumboperitoneal (LP) shunts are rare. Symptoms often resolve following shunt replacement with a silicone-free hypoallergenic shunt. We describe novel cases of allergies to both standard and hypoallergenic shunts and highlight the utility of patch testing. Patient 1, a 24-year-old female with Chiari I malformation, developed diarrhea, abdominal pain, and rash along the LP shunt tract. Patch testing was positive. The shunt was replaced with a hypoallergenic VP shunt with symptom improvement. Five weeks later, she developed a new rash. Subsequent patch testing to the hypoallergenic shunt was positive. Patient 2, a 37-year-old female with Chiari I malformation, developed pruritus along the VP shunt tract. Patch testing to the standard shunt was positive. The shunt was replaced with a hypoallergenic shunt, with symptomatic improvement. One month later, she developed neck pain, headache, and pruritis. Patch testing to the hypoallergenic shunt was positive. The development of a pruritic rash along the shunt tract with or without gastrointestinal symptoms should prompt shunt allergy evaluation and consideration of patch testing to the shunt material.

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.

Cerebrospinal Fluid Shunting Complications in Children

Although cerebrospinal fluid (CSF) shunt placement is the most common procedure performed by pediatric neurosurgeons, shunts remain among the most failure-prone life-sustaining medical devices implanted in modern medical practice. This article provides an overview of the mechanisms of CSF shunt failure for the 3 most commonly employed definitive CSF shunts in the practice of pediatric neurosurgery: ventriculoperitoneal, ventriculopleural, and ventriculoatrial. The text has been partitioned into the broad modes of shunt failure: obstruction, infection, mechanical shunt failure, overdrainage, and distal catheter site-specific failures. Clinical management strategies for the various modes of shunt failure are discussed as are research efforts directed towards reducing shunt complication rates. As it is unlikely that CSF shunting will become an obsolete procedure in the foreseeable future, it is incumbent on the pediatric neurosurgery community to maintain focused efforts to improve our understanding of and management strategies for shunt failure and shunt-related morbidity.

Ventricular catheter development: past, present, and future

Cerebrospinal fluid diversion via ventricular shunting is the prevailing contemporary treatment for hydrocephalus. The CSF shunt appeared in its current form in the 1950s, and modern CSF shunts are the result of 6 decades of significant progress in neurosurgery and biomedical engineering. However, despite revolutionary advances in material science, computational design optimization, manufacturing, and sensors, the ventricular catheter (VC) component of CSF shunts today remains largely unchanged in its functionality and capabilities from its original design, even though VC obstruction remains a primary cause of shunt failure. The objective of this paper is to investigate the history of VCs, including successful and failed alterations in mechanical design and material composition, to better understand the challenges that hinder development of a more effective design.

Influence of congenital central nervous system malformations on postoperative complications following placement of cerebrospinal fluid shunts in pediatric and adolescent patients

BACKGROUND

This retrospective study was designed to evaluate whether patients with hydrocephalus associated with central nervous system (CNS) anomalies, compared with patients with hydrocephalus and absent CNS anomalies, present with significantly higher rate of postoperative complications, including more serious clinical presentation, increased life threat, and higher postoperative or late mortality rate.

METHODS

We performed a retrospective study using medical records of 100 patients of pediatric and adolescent age (0-18 years) between 2004 and 2010 treated with operative cerebrospinal fluid (CSF) shunt placement.

RESULTS

In both groups of patients, there were 43 postoperative complications, including 12 mechanical obstructions of the CSF drainage systems, 13 disconnections, 11 dislocations of proximal catheter, 6 inflammatory complications (meningitis), and 1 latex allergy. Patients with hydrocephalus associated with CNS anomalies were presented with statistically higher rate of postoperative complications (U = 303.5, z = -3.27, p = 0.001), higher number of operations, at least one complication more per patient, more complicated clinical course, higher life threat, and higher late mortality rate.

CONCLUSIONS

After installing the CSF drain system, children and adolescents with hydrocephalus associated with anomalies of the CNS require regular and careful follow-up.

Pathophysiology of shunt dysfunction in shunt treated hydrocephalus

BACKGROUND

We hypothesized that shunt dysfunction in the ventricular catheter and the shunt valve is caused by different cellular responses. We also hypothesized that the cellular responses depend on different pathophysiological mechanisms.

METHODS

Removed shunt material was collected. Macroscopic tissue in the catheters was paraffin-embedded and HE-stained. Valves were incubated with trypsin-EDTA in order to detach macroscopically invisible biomaterial, which was then cytospinned and HE-stained. Associated aetiological and surgical data were collected by reviewing patient files, and ventricular catheter position was examined using preoperative radiology (CT scans).

RESULTS

We examined eleven ventricular catheters and ten shunt valves. Catheters: 6/11 catheters contained intraluminal tissue consisting of vascularised glial tissue and inflammatory cells (macrophages/giant cells and a few eosinophils). Catheter adherence correlated with the presence of intraluminal tissue, and all tissue containing catheters had some degree of ventricle wall contact. All obstructed catheters contained intraluminal tissue, except one catheter that was dysfunctional because of lost ventricular contact. Valves: Regardless of intraoperative confirmation of valve obstruction, all ten valves contained an almost uniform cellular response of glial cells (most likely ependymal cells), macrophages/giant cells, and lymphomonocytic cells. Some degree of ventricle wall catheter contact was present in all examined valves with available radiology (9/10).

CONCLUSIONS

The same cellular responses (i.e., glial cells and inflammatory cells) cause both catheter obstruction and valve obstruction. We propose two synergistic pathophysiological mechanisms. (1) Ventricle wall/parenchymal contact by the catheter causes mechanical irritation of the parenchyma including ependymal exfoliation. (2) The shunt material provokes an inflammatory reaction, either nonspecific or specific. In combination, these mechanisms cause obstructive tissue ingrowth (glial and inflammatory) in the catheter and clogging of the valve by exfoliated glial cells and reactive inflammatory cells.

Foreign body granuloma secondary to ventriculo-peritoneal shunt: a rare scenario with a new insight

Ventriculo-peritoneal shunts are used extensively for the management of hydrocephalus and frequently present with complications such as shunt blockage and infection. Cerebrospinal fluid (CSF) eosinophilia and allergic responses to the shunt itself are rare, poorly understood but increasingly recognised complications. Here, the authors describe a child who required multiple shunt revision surgeries due to extensive scalp tenderness overlying the shunt tubing and persistent severe headaches despite having a normal working shunt and no CSF infection or eosinophilia. Histological investigation of excised tissue during the last shunt revision demonstrated fibrosis with scar tissue and chronic inflammatory infiltrate with foreign body giant cells and few abortive granulomata. This was felt to represent a foreign body reaction to the shunt. A hypoallergenic 'extracted' shunt was trialled (extracted Delta® valve and extracted ventricular and peritoneal catheters; Medtronic) and the child has had no further shunt revisions and is currently asymptomatic 1 year after the insertion.

What We Should Know About the Cellular and Tissue Response Causing Catheter Obstruction in the Treatment of Hydrocephalus

The treatment of hydrocephalus by cerebrospinal fluid shunting is plagued by ventricular catheter obstruction. Shunts can become obstructed by cells originating from tissue normal to the brain or by pathological cells in the cerebrospinal fluid for a variety of reasons. In this review, the authors examine ventricular catheter obstruction and identify some of the modifications to the ventricular catheter that may alter the mechanical and chemical cues involved in obstruction, including alterations to the surgical strategy, modifications to the chemical surface of the catheter, and changes to the catheter architecture. It is likely a combination of catheter modifications that will improve the treatment of hydrocephalus by prolonging the life of ventricular catheters to improve patient outcome.

Cerebrospinal fluid eosinophilia associated with intraventricular shunts

CSF eosinophilia (CSF-eo) is uncommon and is usually caused by helminthic infections. However, it has also been found in ∼30% of patients experiencing intraventricular shunt malfunctions. We present a case report and review the conditions associated with CSF-eo and their prophylaxis. An 8 year-old boy with tetraventricular hydrocephalus has had several shunt malfunctions over the last three years. During hospitalization in January 2009 for shunt revision, a transient 30% eosinophilia was detected in his cerebral spinal fluid (CSF) concomitant with Staphylococcus epidermidis infection and long term vancomycin administration. After several shunt replacements and antibiotic treatment, CSF-eo eventually disappeared with good overall clinical response. CSF-eo is a transient and focal event mainly associated with infection, reactions to foreign substances, particles or blood, or obstruction of tubing by normal or fibro-granulomatous tissues. Infection associated with CSF-eo is usually caused by S. epidermidis and Propioniumbacterium acnes. In addition to infection, allergy to silicone and other foreign materials may also be a cause of CSF-eo. We review the diversity of conditions and proposed mechanisms associated with CSF-eo, as well as recommendations for the care of patients with shunts. Detection of CSF-eo has been shown to be a useful indicator of shunt malfunction. As such, it provides physicians with an indicator of a hypersensitivity reaction that is underway or the need to identify bacterial infection. We also highlight the need for improved biocompatibility of shunt hardware and describe strategies to avoid conditions leading to shunt malfunction.

Reducing surface area while maintaining implant penetrating profile lowers the brain foreign body response to chronically implanted planar silicon microelectrode arrays

A consistent feature of the foreign body response (FBR), irrespective of the type of implant, is persistent inflammation at the biotic-abiotic interface signaled by biomarkers of macrophage/microglial activation. Since macrophage-secreted factors shape the foreign body reaction, implant designs that reduce macrophage activation should improve biocompatibility and, with regard to recording devices, should improve reliability and longevity. At present, it is unclear whether the goal of seamless integration is possible or whether electrode developers can modulate specific aspects of the FBR by intentionally manipulating the constitutive properties of the implant. To explore this area, we studied the chronic brain FBR to planar solid silicon microelectrode arrays and planar lattice arrays with identical penetrating profiles but with reduced surface area in rats after an 8-week indwelling period. Using quantitative immunohistochemistry, we found that presenting less surface area after equivalent iatrogenic injury is accompanied by significantly less persistent macrophage activation, decreased blood brain barrier leakiness, and reduced neuronal cell loss. Our findings show that it is possible for implant developers to modulate specific aspects of the FBR by intentionally manipulating the constitutive properties of the implant. Our results also support the theory that the FBR to implanted electrode arrays, and likely other implants, can be explained by the presence of macrophages at the biotic-abiotic interface, which act as a sustained delivery source of bioactive agents that diffuse into the adjacent tissue and shape various features of the brain FBR. Further, our findings suggest that one method to improve the recording consistency and lifetime of implanted microelectrode arrays is to design implants that reduce the amount of macrophage activation at the biotic-abiotic interface and/or enhance the clearance or impact of their released factors.