MIETHKE SA 2.0 Shunt Assistant User Manual

: June 13, 2024
: MIETHKE

MIETHKE SA 2.0 Shunt Assistant

IMPORTANT INFORMATION

This Instructions for Use is NOT intended for United States users. Please discard.

The Instructions for Use for United States users can be obtained by visiting our website at www.aesculapusa.com
If you wish to obtain a paper copy of the Instructions for Use, you may request one by contacting your localAesculap representative or Aesculap’s customer service at 1-800-282-9000. A paper copy will be provided to you upon request at no additional cost.

PRODUCT DESCRIPTION

Titanium housing
Tantalum ball (weight ball)
Sapphire ball (Locking ball)
Ball seat
Inlet connector
Coding
Outlet connector

INDICATION

The SHUNTASSISTANT 2.0 (SA 2.0) is used for cerebrospinal fluid (CSF) drainage in the treatment of hydrocephalus.

TECHNICAL DESCRIPTION

The SA 2.0 is a valve made from titanium, which contains a so-called gravitational unit. The SA 2.0 was developed as an additional valve (gravitational unit) in order to provide the opportunity of controlling the siphon effect in combination with a conventional or adjustable valve. In doing so, particular attention was paid to avoiding negative influences, such as changes to the subcutaneous pressure (e.g. due to tissue capsules or adverse patient position). The SA 2.0 consists of a durable titanium housing, a heavy tantalum ball as well as a small sapphire ball, which is positioned on the ball seat. The fluid flows in through the inlet connector and out through the outlet connector.

FUNCTION OF THE VALVE

The SA 2.0 is a position-dependent valve.

Horizontal position

In the horizontal position, the gravitational unit is always open and does not present any resistance. The opening pressure is exclusively determined by an additional differential pressure valve in this body position.

Fig. 2: SA 2.0 in horizontal body position

Vertical position

When the patient moves into an upright position, the gravitational unit is activated. In an upright position, the SA 2.0 and another differential pressure valve operate together. If the sum of the intraventricular pressure and hydrostatic pressure exceeds the valve opening pressure of both the differential pressure valve as well as the SA 2.0, the locking and the tantalum ball are raised to enable the discharge of fluid from the outlet connector. In order to ensure the optimal individual adjustment to the patient, the SA 2.0 is offered in six pressure levels.

Fig. 3 : SA 2.0 in vertical body position
a) closed
b) open

SELECTION OF THE APPROPRIATE PRESSURE LEVEL

Patient size, activity level and potentially increased abdominal pressure (obesity) should be taken into account in selecting the opening pressure for this position (see pressure level recommendations at https://www.miethke.com/downloads).

PRESSURE LEVELS RECOGNITION IN X-RAY IMAGES

The selected pressure levels can be detected radiographically after implantation.

Fig. 4: SA 2.0 pressure levels encodings on X-ray

Opening Pressure	Coding
10 cmH2O SA 2.0
15 cmH2O SA 2.0
20 cmH2O SA 2.0
25 cmH2O SA 2.0
30 cmH2O SA 2.0
35 cmH2O SA 2.0

TUBE SYSTEMS

The SA 2.0 is designed so that it ensures the optimal ventricular pressure in combination with an additional conventional or adjustable differential pressure valve. We advise using a catheter with an inner diameter of 1.2 mm and an outer diameter of approx. 2.5 mm for connection. In any case, catheters have to be carefully fixed with a ligature to the valve’s titanium connectors. The catheters must not contain any kinks. The supplied catheters do not fundamentally change the pressure-flow characteristics.

IMPLANTATION

Positioning the ventricular catheter

Several surgical techniques are available for positioning the ventricular catheter. The required skin incision should be made in form of a lobule pedicled towards the draining catheter. If a burrhole deflector is used, the skin incision should not be located right above the reservoir. To avoid CSF leakage, care should be taken that the dura opening is kept as small as possible after applying the burrhole. The SA 2.0 is available in a range of different configurations: If a burrhole reservoir is used, the ventricular catheter is implanted first. Once the introducing stylet has been removed, the patency of the ventricular catheter can be tested by checking if cerebrospinal fluid is dripping out. The catheter is shortened and connected the burrhole reservoir connected, with the connection secured with a ligature. A shunt system with prechamber comes with a burrhole deflector. The deflector is used for adjusting the length of catheter to be implanted and for its positioning inside the ventricle. The ventricular catheter is deflected, connected to the prechamber, and the prechamber is put into place. The position of the ventricular catheter should be inspected after the procedure by imaging (such as CT or MRI).

Positioning the valve

Operation of the SA 2.0 is posture-dependent. For that reason, care must be taken to implant the valve parallel to the body axis. Depending on the anatomical relationships, for a VP shunt system, we advise implanting the SA 2.0 in the area of the thorax for adults and, due to growth problems, subcutaneously behind the ear for children. For LP drainage, the valve in place in a subcutaneous skin pocket in the abdominal or back region. If an SA 2.0 is used without integrated catheters, the catheters (proximal and distal) must be fastened by a ligature. The valve should not be located directly under the skin incision. The implant may be pulled forward to the desired implant height using the peritoneal catheter. Make sure that the catheter is not bent excessively. Also make sure that components (e.g. tissue material) is prevented from entering the SA 2.0 during implantation. The valve is marked with an arrow indicating the distal direction of flow.

CAUTION

The catheters should only be blocked with a sheathed clamp and not directly behind the valve as they might be damaged otherwise

Positioning the peritoneal catheter

The access site for the peritoneal catheter is left to the surgeon’s discretion. For example, it can be applied paraumbically in a horizontal direction or at the height of the epigastrium. Likewise, various surgical techniques are available for positioning the peritoneal catheter. The recommendation is to pull the peritoneal catheter using a subcutaneous tunnelling tools from the valve to the intended position, if necessary with the aid of an auxiliary incision. The peritoneal catheter which is usually securely attached to the valve has an open distal end and no wall slits. Following the exposure of the peritoneum or with the aid of a trocar, the peritoneal catheter (shortened if necessary) is pushed forward into the open space of the abdominal cavity

Reimplantation

Products that have previously implanted must not subsequently be reimplanted into the same or another patient.

VALVE TEST

Preoperative valve test

The most careful way of filling the valve is by aspiration through a sterile single-use syringe attached to the distal end of the catheter. The distal end of the valve is connected and immersed in a sterile physiological salt solution. The valve is patent if saline solution can be extracted (Fig. 5)

** WARNING**

Contamination in the solution used for testing can impair the product‘s performance.

Fig. 5 : Patency test

WARNING

Pressurisation by the single-use syringe should be avoided both at the proximal and the distal end (fig. 6).

Fig. 6: Avoidance of pressurisation

Postoperative valve test

The SA 2.0 has been constructed as a reliably functioning unit without pump or test function. The valve test can be performed by flushing, pressure measurement or pumping.

PRESSURE-FLOW CHARACTERISTICS

The following diagrams show the pressure-flow characteristics for the available pressure settings of the SA 2.0 (Fig. 7). The total opening pressure refers to a reference flow of 5 ml/h. For flow rates of 20 ml/h, stated pressures are approx. 1-2 cmH2 O higher

Fig. 7: Pressure-flow characteristics for the available pressure

settings of the SA 2.0

PRECAUTIONS AND CONTRAINDICATIONS

Patients must be carefully monitored after implantation. Reddening of skin or tightness in the area of the drained tissue may be indications of infections at the shunt system. Symptoms such as headache, dizziness, confusion or vomiting often occur in conjunction with shunt dysfunction. These symptoms and a leakage within the shunt system require the immediate replacement of the affected shunt component or the entire shunt system.

The implantation of medical devices is contraindicated if the patient has an infection or suspected infection (e.g. meningitis, ventriculitis, peritonitis, bacteriaemia, septicaemia) in the region affected by the implantation.

FUNCTIONAL SAFETY AND COMPATIBILITY WITH DIAGNOSTIC PROCEDURES

These medical devices are constructed in such a way as to ensure their precise and reliable operation over long periods of time. However, we cannot guarantee that these medical devices will require replacement for medical or
technical reasons. These medical devices are able to resist positive and negative pressures up to 100 cmH2 O during and after implantation. These medical devices have to be stored in a clean and dry environment at all times.

Nuclear magnetic resonance examinations up to a field strength of 3 Tesla or computed tomography examinations can be performed without risk or impairment to the valve function. The valve is MR Conditional. Supplied catheters are MR Safe. Reservoirs, deflectors and connectors are MR Conditional. The conditions for MR compatibility of the products can be found on our website:https://www.miethke.com/downloads

ADVERSE REACTIONS AND INTERACTION

In the treatment of hydrocephalus with shunts, the following complications may arise (as described in the literature): infections, blockages caused by protein and/or blood in the cerebrospinal fluid, over/under drainage or in very rare cases noise development. Violent shocks for the outside (accident, fall) may put the integrity of the shunt system at risk.

The SA 2.0 must not be used in conjunction with hydrostatic valves as this may result in increased ventricular pressure outside of the physiological range. In case of doubt, please contact the medical device consultants at Christoph Miethke GmbH & Co. KG.

STERILISATION

The products are sterilised with steam under strictly controlled conditions. The double wrapping in sterile bags ensures sterility for a fiveyear period. The expiry date is printed on the wrapping of each individual product. If the packaging is damaged, the product must not be used in any circumstances. No guarantee can be given for the functional safety and reliability of resterilised products.

REQUIREMENTS OF THE MDD (DIRECTIVE 93/42/EEC)

The Medical Device Directive requires the comprehensive documentation of the whereabouts of medical devices used in humans. The individual identification number of the implanted valveshould therefore be recorded in the patient’ medical records and patient data card to ensure complete traceability.

Translations of these instructions for use into additional languages can be found on our website: https://www.miethke.com/downloads

MEDICAL PRODUCTS CONSULTANTS

In compliance with European directive on medical devices (directive 93/42/EEC), Christoph Miethke GmbH & Co. KG has nominated medical products consultants as contacts for all product-related questions:

You can contact our medical devices consultants via:

Tel. +49 331 62083-0
info@miethke.com