Ares

Indications, Safety, and Warnings

Indications

For use in the treatment of hydrocephalus as a component of a shunt system when draining or shunting of cerebrospinal fluid (CSF) is indicated.

Contraindications

Shunting of CSF into the peritoneal cavity, right atrium, or other areas of the body should not be carried out if there is infection in any area of the body. Additionally, shunting in the atrium of patients with congenital heart disease, or other serious cardiopulmonary abnormalities, is contraindicated.

Do not implant this device in patients with known hypersensitivity to rifampin or clindamycin hydrochloride.

Use of this device is contraindicated in patients receiving anticoagulants or known to have a bleeding diathesis.

Warnings and Precautions

• Do not immerse the ARES catheter in antibiotic solutions. When immersing the catheter in sterile water or saline, keep the time the catheter is immersed to a minimum. A pale orange color may be imparted to the immersion solution.
• Avoid contacting implantable products with lint, glove talc, oily residue from skin, oil based soaps, or other surface contaminants. Introduction of contaminants could result in improper performance of components, foreign body reactions, or allergic reactions.
• Improper use of instruments in handling or implanting shunt products may result in the cutting, slitting or crushing of components. Such damage may lead to loss of shunt integrity, and necessitate premature surgical revision of the shunt system.
• Care must be taken to ensure that particulate contaminants are not introduced into shunt components during implantation, testing, or handling. Introduction of contaminants could result in improper performance (over- or under-drainage) of the shunt system. Particulate matter which enters the shunt system may result in shunt occlusion, or may hold pressure/flow controlling mechanisms open, resulting in overdrainage.
• The encircling ligatures used to fasten catheters to connectors should securely fasten the catheters to the connectors. However, over-tightening the ligatures could eventually result in cutting through the silicone tubing.
• Care must be taken in the routing of catheters to prevent kinking and needless abrasion along their course. Abrasion can result in premature catheter failure (fracture). The rim of the twist drill or burr hole may be trimmed to provide a beveled notch where the ventricular catheter emerges and is curved to lie adjacent to the skull.
• Patients with hydrocephalus shunt systems must be kept under close observation in the postoperative period for signs and symptoms that suggest shunt malfunction. Clinical findings may indicate infection, shunt obstruction, and/or overdrainage of CSF.
• Shunt obstruction may occur in any component of the shunt system. The ventricular catheter may become occluded by particulate matter (e.g. blood clots, brain fragments, and bacterial colonization), by investment of the catheter tip in choroid plexus, by embedding of the catheter in brain tissue, or by coaptation of the ventricular walls in the presence of overdrainage (“slit ventricles”). Shunt obstruction may occur due to growth of the child, or physical activities which result in the disconnection of the shunt components or withdrawal of a distal catheter from its intended drainage site.
• Separation of the components of a shunt system due to disconnection or catheter fracture has been reported. In some cases, the separated shunt components have migrated into the cerebral ventricles, the heart, or the peritoneal cavity. Shunt systems may fail due to mechanical malfunction, leading to under- or over-drainage.
• Malfunction or obstruction of the shunt system may lead to signs and symptoms of increased intracranial pressure if the hydrocephalus is not compensated. In the infant, common symptoms may include increased tension of the anterior fontanel, congestion of scalp veins, listlessness, drowsiness and irritability, vomiting and nuchal rigidity. In older children and adults, common symptoms may include headaches, vomiting, blurring of vision, nuchal rigidity, deterioration of consciousness, and various abnormal neurological findings.
• Overdrainage of CSF may predispose development of a subdural hematoma or hydroma or collapse of the lateral ventricular walls leading to obstruction of the ventricular catheter.
• If the ventricular catheter becomes bound to the choroid plexus or adjacent brain tissue by fibrous adhesions, it is suggested that the catheter should not be removed forcibly. Gentle rotation of the catheter may help to free it and allow for non-forcible removal. It is advised that the catheter be left in place rather than risk intraventricular hemorrhage which may be caused by forcible removal.

Storage

• Store this product below 27 °C (80 °F), away from direct light. Do not remove the product from the packaging until it will be used.

Complications

• Complications associated with ventriculoatrial and ventriculoperitoneal CSF shunting systems may be similar to those experienced in any surgical procedure carried out under local and/or general anesthesia. These include reactions to drugs and anesthetic agents, electrolyte imbalance, and excessive blood loss, particularly in infants. On rare occasions, the patient may exhibit a reaction due to sensitivity to the implant. Use of sharp instruments while handling these devices can nick or cut the silicone elastomer, resulting in leakage and necessitating valve revision. Care must also be taken when closing incisions to ensure that the valves are not cut or nicked by suture needles.
• In all CSF shunting procedures, the most common complications are due to obstruction of the system as described under “Warnings and Precautions.” Obstruction may occur in any component of the system, due to plugging by brain fragments, blood clots, and tumor cell aggregates. Obstructions may also occur because of the separation of shunt components, or kinking and/or coiling of the catheter. This may predispose migration of the ventricular catheter into the lateral ventricle and the distal catheter into the peritoneum, the heart and pulmonary arterial tree, or any other structure in which the catheter is implanted.
• Growth of the child may cause the distal catheter to be withdrawn from the peritoneum into tissue planes where the fluid cannot be absorbed, or from the atrium into the internal jugular vein. In addition to the types of shunt obstructions described above, there are other potentially serious complications. Local and systemic infections are not uncommon with shunting procedures. Usually, they are due to organisms inhabiting the skin, particularly Staphylococcus epidermidis. Other pathogens circulating in the bloodstream may colonize the shunt and, in the majority of patients, require its removal.
• In 1973, Robertson et al. summarized the incidence of infection in ventriculoatrial and ventriculoperitoneal shunts reported up to that time. The incidence of infection in ventriculoatrial shunting varied from 7 to 31%. Infection in ventriculoperitoneal shunting occurred in 5 to 10% of the patients in most of the reports. Because ventriculoatrial shunting predisposes the spread of bacteria into other organs of the body, ventriculoperitoneal shunting is considered less devastating.
• In 1993, Kestle et al. reported significant reductions in infection (less than 4%) with the use of antibiotics, short duration of surgery (surgical experience) and control of the operating room environment (e.g. designated operating room, limited personnel and traffic, covered skin surfaces) The article states that results can also be obtained without the use of antibiotics, but with rigorous perioperative control of the environment.
• The use of prophylactic antibiotics in shunted patients is somewhat controversial because their use may predispose infection by more resistant organisms. The decision to use antibiotics prophylactically rests with the attending physician and/or surgeon.
• Shunting into the peritoneum may fail because of investments of the catheter in loops of bowel or in the greater omentum. Perforation of the bowel by the peritoneal catheter with subsequent development of peritonitis has been described.
• Overdrainage of CSF may result in excessive reduction of CSF pressure and predispose the development of a subdural hematoma or hydroma, and excessive reduction of ventricular size, leading to obstruction because of impingement of the ventricular walls on the inlet holes in the catheter. In the infant, this excessive reduction of pressure will cause marked depression of the anterior fontanel, overriding of cranial bones, and may convert communicating hydrocephalus into obstructive hydrocephalus.
• The incidence of epilepsy after ventricular shunting procedures has been reported. The study also indicated that the incidence of seizures increased with multiple catheter revisions.

Important Safety Information

The most common complications associated with this product are due to obstruction of the system, infection, and mechanical malfunction. Catheters may become kinked, disconnected, or blocked. It is important to review the product labeling for complete safety information, potential complications, contraindications, and a complete explanation of warnings and precautions.

Shunt obstruction may occur in any of the components of the shunt system. The ventricular catheter may become occluded by particulate matter such as blood clots or brain fragments, by investment of the catheter tip in choroid plexus, by embedding of the catheter in brain tissue, or by coaptation of the ventricular walls in the presence of overdrainage (“slit ventricles”). It is important to review the product labeling for complete safety information, potential complications, contraindications, and a complete explanation of warnings and precautions.

Research shows that there is an increased risk of shunt valve infection in younger patients, especially premature infants, patients who have had a previous shunt infection, and patients who have been on an external drainage system. Shunt infections are associated with much greater morbidity for patients, as well as increased costs to healthcare providers and society. Complications include additional surgeries and lengthened hospital stays, developmental disabilities and loss of IQ, and death.

Caution: Federal (USA) law restricts this device to sale by or on the order of a physician. Refer to product package insert for instructions, warnings, precautions and complications