Ventriculoperitoneal Shunt

Article Author:
James Fowler
Article Editor:
Fassil Mesfin
Updated:
1/28/2019 8:52:37 AM
PubMed Link:
Ventriculoperitoneal Shunt

Introduction

A ventriculoperitoneal shunt (VPS) also known as cerebral shunt is one the high impact advances made in neurosurgical patient care.  Cerebral shunts are used to treat hydrocephalus. If left unchecked, excess cerebrospinal fluid (CSF) can increase intracranial pressure (ICP) resulting in herniation, intracranial hematoma, cerebral edema, or crushed brain tissue. In pediatric patients, untreated hydrocephalus can lead to many adverse effects including increase irritabilities, chronic headaches, learning difficulties, visual disturbances, and in more advanced cases severe mental retardation.  [1][2][3]

Shunts consist of a valve housing connected to a catheter, the distal end of which is placed in the peritoneal cavity. The main differences between shunts are the materials used to construct them, the types of valve, and whether the valve is programmable or not. Advances in the biotechnologies are leading to progressive changes in shunt components.  These advanced components are expected to reduce shunt malfunctions and optimize neurosurgical patient care.

Anatomy

Placement of cerebral shunt and its location is determined based on the type and location of the blockage causing hydrocephalus. All brain ventricles are candidates for shunting. These include the lateral ventricles, the third ventricle, and the fourth ventricle. The catheter placed in the cerebral ventricle is called the proximal portion of the shunt implying proximity to the brain. The most common proximal shunt location is the right lateral ventricle. The distal (post valve) catheter can be placed in the cardiac atrium via venous, to the chest cavity, bladder, and most commonly placed in the abdomen in peritoneal space. Overall, other locations include the heart and lungs found to be more morbid compared to the abdomen. In all cases, however, the distal end of the catheter can be located in any tissue with epithelial cells capable of absorbing the incoming cerebrospinal fluid (CSF).

A subgaleal shunt is a temporary measure used in infants who are too small or premature to tolerate other shunts. The surgeon forms a pocket beneath the subgaleal space and allows the CSF to drain from the ventricles, creating a fluid-filled swelling on the infant's scalp. As the child grows, these shunts are later converted to a ventriculoperitoneal (VP) or another shunt types.[4][5][6]

Indications

Conditions that typically requiring shunting include the following:

  • Congenital hydrocephalus
  • Tumors leading to CSF blockage of the lateral or third ventricles, the posterior fossa, and intraspinal tumors.
  • Post-hemorrhagic hydrocephalus
  • Spina bifida causes the development of hydrocephalus because the cerebellum blocks the flow of CSF in a development of Chiari Malformation II
  • Congenital aqueductal stenosis is a genetic disorder which can cause deformations of the nervous system and is associated with mental retardation, abducted thumbs, and spastic paraplegia
  • Craniosynostosis occurs when the sutures of the skull close too early with sutures fusing before the brain stops growing causing an increase in ICP leading to hydrocephalus
  • Post-meningitic hydrocephalus caused by meningitis can inhibit CSF absorption
  • Dandy-Walker syndrome presents with a cystic deformity of the fourth ventricle, hypoplasia of the cerebellar vermis, and an enlarged posterior fossa
  • Arachnoid cysts are a defect caused when CSF forms a collection that is trapped in the arachnoid membranes resulting in a block of the normal flow of CSF from the brain resulting in hydrocephalus. Common locations of arachnoid cysts are the middle fossa and the posterior fossa. The most common symptoms are nausea and vertigo
  • Idiopathic intracranial hypertension is a rare neurological disorder affecting approximately 1 in 100,000 people, usually women of childbearing age. It can raise intracranial pressure and result in permanent loss of vision.

Contraindications

Absolute contraindications include infection over the entry site. Relative contraindications include coagulopathy and lack of shunt imaging.

Equipment

A VPS is placed in the operating room by practicing neurological surgeons.

Equipment needed to perform the procedure includes:

  • Sterile gloves
  • Povidone-iodine or chlorhexidine solution
  • Sterile fenestrated drape
  • Butterfly needles, 23 or 25 gauge
  • Syringe, 3 mL to 5 mL
  • Three-way stopcock
  • Gauze swabs
  • Wound dressing
  • Numbered specimen tubes for CSF
  • Cerebrospinal fluid manometer

Personnel

Clinician and surgical assistant.

Preparation

All patients need appropriate preoperative workup and informed consent for surgery and general anesthesia. The patient should be placed supine with the head oriented so that the shunt reservoir lies uppermost. The reservoir is normally located on the right side of the head and feels like a smooth dome under the skin.

Technique

See the list below:

  • Explain the procedure, risks, and benefits
  • Obtain informed consent
  • Review the shunt series imaging
  • Parting, gel, or shave the hair away from the shunt
  • Clean the skin with an antiseptic
  • Apply a sterile fenestrated drape over the reservoir site
  • Fenestrated drape the patient
  • Insert a small (23 ga) butterfly needle perpendicular to the skin into the reservoir. Once entered, once resistance is felt, advance slowly until the bevel of the needle is inside the reservoir holding the needle securely as the cerebrospinal fluid enters the tubing
  • Shunt tap with syringe
  • Measure the opening pressure using a manometer
  • Collect five mL of cerebral spinal into sterile specimen containers
  • Withdraw the needle from the reservoir and apply gentle pressure over the entry site for 2 to 3 minutes
  • Gauze applied to site
  • Send the cerebrospinal fluid sample for cell count, glucose, protein, gram stain, and culture
  • A blood glucose level sample should also be taken.

Complications

Complications include the following:

  • Infection due to skin flora entering the shunt, usually Staphylococcus epidermidis
  • Bleeding from subcutaneous vessels during the tap
  • Cerebrospinal fluid leak from puncture site
  • Ventricular collapse due to rapid aspiration of CSF from a shunt can result in collapse of the ventricles, especially in slit ventricles
  • The misplaced tap can result in the wrong section of tubing is punctured or that components adjacent to the reservoir.

Clinical Significance

Ventriculoperitoneal shunts are used to treat hydrocephalus and shunt cerebrospinal fluid from the lateral ventricles into the peritoneum. Tapping a shunt is performed for both diagnostic and therapeutic reasons (e.g., evaluate for infection and relieve blockage).

The ventricles of the brain are a communicating network of cavities located within the brain parenchyma. The ventricular system is composed of two lateral ventricles, the cerebral aqueduct, and the third and fourth ventricle. The choroid plexuses in the ventricles produce CSF, which fills the subarachnoid space and ventricles in a constant cycle of production and reabsorption.[2][7][8]

Enhancing Healthcare Team Outcomes

There is no question that VP shunts have saved many lives, but these devices are not without complications. Ultimately, it is the nurse who monitors the patient and has to be aware of the potential complications that can occur. Besides monitoring the patient, the shunt sites have to be monitored for infection, obstruction, and kinks. In addition, the abdomen has to be monitored for peritonitis. Anything unusual has to be reported back to the neurosurgeon immediately. Finally, before the patient is discharged, the family has to be educated on the early identification of shunt failure and how to monitor the child's improvement. In some cases, a home care nurse may be required to pay regular visits to ensure that the VP shunt is functioning without problems.[9][10] (Level V)

Outcomes

VP shunts can be lifesaving, but the eventual outcome depends on the reason why the shunt was inserted. For benign disorders, most patients have a good outcome. However, for malignant tumors, the outcomes are usually poor; often these patients die from other causes unrelated to the shunt. The complication rates of VP shunts range from 2-20%. In addition, shunt revision is required in about 5-10% of neonates and young children. [11][12](Level V)


References

[1] Hanna RS,Essa AA,Makhlouf GA,Helmy AA, Comparative Study Between Laparoscopic and Open Techniques for Insertion of Ventriculperitoneal Shunt for Treatment of Congenital Hydrocephalus. Journal of laparoendoscopic     [PubMed PMID: 30307809]
[2] Erps A,Roth J,Constantini S,Lerner-Geva L,Grisaru-Soen G, Risk factors and epidemiology of pediatric ventriculoperitoneal shunt infections. Pediatrics international : official journal of the Japan Pediatric Society. 2018 Oct 5     [PubMed PMID: 30290047]
[3] Kutty RK,Sreemathyamma SB,Korde P,Prabhakar RB,Peethambaran A,Libu GK, Outcome of Ventriculosubgaleal Shunt in the Management of Infectious and Non-infectious Hydrocephalus in Pre-term Infants. Journal of pediatric neurosciences. 2018 Jul-Sep     [PubMed PMID: 30271465]
[4] Hong B,Polemikos M,Heissler HE,Hartmann C,Nakamura M,Krauss JK, Challenges in cerebrospinal fluid shunting in patients with glioblastoma. Fluids and barriers of the CNS. 2018 Jun 4     [PubMed PMID: 29860942]
[5] Spirig JM,Frank MN,Regli L,Stieglitz LH, Shunt age-related complications in adult patients with suspected shunt dysfunction. A recommended diagnostic workup. Acta neurochirurgica. 2017 Aug     [PubMed PMID: 28616668]
[6] Rinaldo L,Lanzino G,Elder BD, Predictors of distal malfunction after ventriculoperitoneal shunting for idiopathic normal pressure hydrocephalus and effect of general surgery involvement. Clinical neurology and neurosurgery. 2018 Sep 5     [PubMed PMID: 30218879]
[7] Pan P, Outcome Analysis of Ventriculoperitoneal Shunt Surgery in Pediatric Hydrocephalus. Journal of pediatric neurosciences. 2018 Apr-Jun     [PubMed PMID: 30090131]
[8] Burhan B,Serdar KB,Abdurrahman A,Edip AM,Ebuzer D, Abdominal Complications of Ventriculoperitoneal Shunt in Pediatric Patients: Experiences of a Pediatric Surgery Clinic. World neurosurgery. 2018 Oct     [PubMed PMID: 29959071]
[9] Tavares PAJ,Hamamoto Filho PT,Ferreira ASSBS,Avila MAG, Construction and Validation of Educational Material for Children with Hydrocephalus and Their Informal Caregivers. World neurosurgery. 2018 Jun     [PubMed PMID: 29567289]
[10] Joseph RA,Killian MR,Brady EE, Nursing Care of Infants With a Ventriculoperitoneal Shunt. Advances in neonatal care : official journal of the National Association of Neonatal Nurses. 2017 Dec     [PubMed PMID: 29166295]
[11] Junaid M,Ahmed M,Rashid MU, An experience with ventriculoperitoneal shunting at keen's point for hydrocephalus. Pakistan journal of medical sciences. 2018 May-Jun     [PubMed PMID: 30034441]
[12] Nakajima M,Miyajima M,Ogino I,Akiba C,Kawamura K,Kurosawa M,Kuriyama N,Watanabe Y,Fukushima W,Mori E,Kato T,Sugano H,Karagiozov K,Arai H, Shunt Intervention for Possible Idiopathic Normal Pressure Hydrocephalus Improves Patient Outcomes: A Nationwide Hospital-Based Survey in Japan. Frontiers in neurology. 2018     [PubMed PMID: 29942280]